2024年6月24日 (一) 07:51的版本

阿霉素（多柔比星）化疗治疗狗的推定性心脏血管肉瘤

Doxorubicin chemotherapy for presumptive cardiac hemangiosarcoma in dogs

1 摘要

64 只狗接受单药多柔比星 （DOX） 治疗推定性心脏血管肉瘤 （cHSA）。客观缓解率（CR + PR）为41%，生物缓解率（CR + PR + SD）或临床获益为68%。接受治疗的狗的中位无进展生存期 （PFS） 为 66 天。该组的中位生存时间 （MST） 为 116 天，与未经治疗的对照犬的 12 天的 MST 相比显着改善 （P = 0.0001）。生物反应与PFS（P < 0.0001）和OS（P < 0.0001）的改善显著相关。单因素分析发现较大的肿瘤大小是与PFS呈负相关的变量。较高的临床获益率和改进的 MST 表明 DOX 在犬 cHSA 中具有活性。

Sixty-four dogs were treated with single-agent doxorubicin (DOX) for presumptive cardiac hemangiosarcoma (cHSA). The objective response rate (CR + PR) was 41%, and the biologic response rate (CR + PR + SD), or clinical benefit, was 68%. The median progression-free survival (PFS) for treated dogs was 66 days. The median survival time (MST) for this group was 116 days and was significantly improved compared to a MST of 12 days for untreated control dogs (P = 0.0001). Biologic response was significantly associated with improved PFS (P < 0.0001) and OS (P < 0.0001). Univariate analysis identified larger tumour size as a variable negatively associated with PFS. The high rate of clinical benefit and improved MST suggest that DOX has activity in canine cHSA.

2 介绍

血管肉瘤 （HSA） 是一种高度侵袭性的恶性内皮细胞及其前体肿瘤，是狗中最常见的心脏肿瘤，心脏是该肿瘤仅次于脾脏的第二大常见解剖位置。在一项针对犬类心脏肿瘤的大型回顾性研究中[1]，HSA 的报告频率是任何其他心脏肿瘤类型的 10 倍。心脏HSA（cHSA）最常位于右心房或耳廓，在心脏其他部位很少见[2]。与脾脏表现一样，金毛猎犬、拉布拉多猎犬和德国牧羊犬的 cHSA 报告常见[3-6]。

Hemangiosarcoma (HSA), a highly aggressive tumour of malignant endothelial cells and their precursors, is the most common cardiac tumour in the dog, and the heart represents the second most common anatomic location for this tumour after the spleen. In a large retrospective study of canine cardiac tumours,1 HSA was reported 10 times more frequently than any other cardiac tumour type. Cardiac HSA (cHSA) is most often located in the right atrium or auricle, although can be infrequently found in other cardiac locations.2 Like the splenic presentation, golden retrievers, Labrador retrievers and German shepherds are often over-represented in reports of cHSA.3-6

HSA 的生物学行为包括侵袭性原发性肿瘤生长和病程早期的广泛转移，肿瘤破裂和不受控制的出血是这些患者最常见的死亡原因[3-6]。患有 cHSA 的狗最常见的表现包括与急性出血相关的临床体征，导致心包积液和随后的心包填塞。最近的一项研究[2] 记录了 75% 的犬 cHSA 患者存在远处转移。不常见的是，狗同时出现脾脏和心脏受累[7]。在这些病例中，很难确定这些发现是否代表同步独立的原发性肿瘤或从一个部位转移到另一个部位。

The biologic behaviour of HSA consists of invasive primary tumour growth and widespread metastasis early in the course of disease, with tumour rupture and uncontrolled haemorrhage being the most common cause of death in these patients.3-6 The most frequent presentation for dogs with cHSA consists of clinical signs related to acute haemorrhage resulting in pericardial effusion and subsequent cardiac tamponade. A recent study2 documented the presence of distant metastasis in 75% of canine patients with cHSA. Uncommonly, dogs present with concurrent involvement of both the spleen and heart;7 in these cases, it is difficult to determine whether these findings represent synchronous independent primary tumours or metastasis from one site to the other.

很少有大规模研究批判性地评估患有 cHSA 的狗的手术和药物治疗。相反，对于更常见的脾脏表现，脾切除术后辅助多柔比星 （DOX） 化疗是迄今为止最有效的方法，一致证明为没有可测量转移性疾病的狗提供 5 至 8 个月的生存获益[8-15]。 患有 cHSA 的狗的中位生存时间 （MST） 仍然明显低于脾表现， 可能是由于与脾脏或肝脏肿块相比，难以获得心脏肿瘤的局部控制。cHSA 原发性肿瘤切除术的可行性取决于许多因素，包括肿瘤体积小、肿瘤局限于右心耳/耳廓或心房游离壁、冠状动脉和心脏瓣膜不受累，以及如果进行心房游离壁切除术，能否构建心包补片移植物以替换切除的组织[16-18] 直观地说， 这些规范将手术切除肿瘤的适用性限制在有限的狗群中。一些病例报告连续记录了通过不同方法接受手术切除肿瘤的个别患者的令人鼓舞的结果[16-22]。然而，尚未进行大规模研究评估手术治疗对该肿瘤的益处。因此，cHSA的手术干预通常包括包括心包切除术的姑息性方法。尽管该手术可以为患有非血管性心底肿瘤的狗提供长期生存，但对于那些患有 cHSA 仅接受心包切除术的狗来说[23]， 的生存时间历来不足[24]。

Few large-scale studies exist which critically evaluate the surgical and medical treatment of dogs with cHSA. Conversely, for the more common splenic presentation, splenectomy followed by adjuvant doxorubicin (DOX)-based chemotherapy has been the most efficacious approach to date, consistently documented to provide a survival benefit in the 5- to 8-month range for dogs presenting without measureable metastatic disease.8-15 The median survival times (MSTs) for dogs with cHSA remain notably lower than those achieved for the splenic presentation, likely due to the difficultly in obtaining local control for a cardiac tumour as compared with a splenic or hepatic mass. The feasibility of primary tumour resection for cHSA depends on numerous factors, including small tumour size, restriction of the tumour to the right atrial appendage/auricle or atrial free wall, lack of involvement of coronary arteries and heart valves, and the ability to construct a pericardial patch graft to replace resected tissue if atrial free wall resection is performed.16-18 Intuitively, these specifications restrict the applicability of surgical tumour removal to a limited group of dogs. A few case reports and series document encouraging results of individual patients undergoing surgical tumour removal through varying methods;16-22 however, no large-scale studies evaluating the benefit of surgical therapy for this tumour have been conducted. Thus, surgical intervention for cHSA typically encompasses a palliative approach involving pericardiectomy. Although this procedure can provide long-term survival for dogs with non-vascular heart-base tumours,23 survival times have historically fallen short for those dogs with cHSA undergoing pericardiectomy alone.24

即使手术切除肿瘤是可行的，如果不与辅助全身治疗联合使用，从历史上看也只能带来短期益处，因为患者总是会死于转移性疾病。脾切除术后接受辅助化疗的脾 HSA 狗的 MST 是单独脾切除术的两倍多[3]。这支持了对这种肿瘤的其他表现（包括心脏表现）采用类似方法的基本原理。最近，一项针对 51 只犬 cHSA 的流行病学研究[2] 报告称，与未接受 DOX 辅助化疗的 5 只狗相比，5 只在肿瘤切除后接受 DOX 辅助化疗的狗的 MST 明显更长（189 天）。同样，一项评估 23 只患有孤立性右心房 HSA 的狗的回顾性研究表明，与未接受化疗的狗相比，接受心包切除术、肿瘤切除术和 DOX 化疗的 8 只狗的生存时间明显更长（中位数，175 天）[22]。另外两份接受右心房肿块切除术然后化疗的狗的病例报告与这些发现一致， 报告的生存时间为 260 天和 177 天[19][21]。 尽管病例数量历来有限，但上述研究的结果令人鼓舞。

Even if surgical tumour removal is feasible, it is historically of only short-term benefit if not combined with adjuvant systemic therapy, as patients invariably succumb to metastatic disease. Dogs with splenic HSA undergoing adjuvant chemotherapy after splenectomy enjoy MSTs more than double of those achieved with splenectomy alone.3 This supports the rationale for a similar approach for other presentations of this tumour, including the cardiac manifestation. Recently, an epidemiological study2 of 51 canine cHSA reported a significantly longer MST (189 days) for 5 dogs that received adjuvant chemotherapy with DOX after tumour resection compared with 12 dogs that did not. Similarly, a retrospective study evaluating 23 dogs with solitary right atrial HSA showed that the subset of 8 dogs undergoing a combination of pericardiectomy, tumour resection and DOX chemotherapy experienced significantly longer survival times (median, 175 days) compared with those dogs that did not receive chemotherapy (median, 42 days).22 Two other case reports of dogs undergoing right atrial mass resection followed by chemotherapy concurred with these findings, with reported survival times of 260 and 177 days.19, 21 Although the number of cases has been historically limited, the results of the aforementioned studies are encouraging.

将原发肿瘤手术切除和辅助化疗相结合的积极和多模式治疗方法明确适用于犬心脏 HSA。然而，对于无法手术的心脏肿瘤，或手术是不利选择的患者，有必要考虑单独将全身治疗作为合理的第二选择。两项研究评估了基于 DOX 的化疗方案对患有宏观非心脏 HSA 的狗的效用，报告了 38 和 47% 的令人鼓舞的反应率[25][26]。最近，据报道，用各种基于 DOX 的方案治疗可测量右心房肿瘤的狗的 MST 为 140 天[27]。然而，本研究中的数量有限 （n = 16），并且治疗和反应评估没有标准化。最后，最近的一项研究评估了 VAC（长春新碱/DOX/环磷酰胺）化疗对患有 I 期（孤立性原发性肿瘤）、II 期（孤立性原发性肿瘤，>5 厘米；破裂的孤立性原发性肿瘤；或具有区域淋巴结转移的孤立性原发性肿瘤）和 III 期（具有转移性或多中心疾病的原发性肿瘤）HSA 的效用，来自不同解剖位置的 HSA 报告了 86% 的反应率患有可测量疾病的狗。 只有不到 50% 的狗接受了正式的反应评估，只有 5 只狗有心脏表现。

An aggressive and multimodal therapeutic approach combining surgical removal of the primary tumour and adjuvant chemotherapy is clearly indicated for canine cardiac HSA. However, in the cases of inoperable cardiac tumours, or those patients for which surgery is an unfavourable option, the consideration of systemic therapy alone as a reasonable secondary option is warranted. Two studies evaluating the utility of DOX-based chemotherapy protocols for dogs with macroscopic non-cardiac HSA reported encouraging response rates of 38 and 47%.25, 26 More recently, an MST of 140 days was reported for dogs treated with various DOX-based protocols for measureable right atrial tumours.27 However, numbers in this study were limited (n = 16), and treatment and response assessments were not standardized. Finally, a recent study evaluating the utility of VAC (vincristine/DOX/cyclophosphamide) chemotherapy for dogs with stage I (solitary primary tumour), stage II (solitary primary tumour, >5 cm; ruptured solitary primary tumour; or solitary primary tumour with regional lymph node metastasis), and stage III (primary tumour with metastasis or multicentric disease) HSA arising from various anatomic locations reported an 86% response rate for dogs with measureable disease.28 However, fewer than 50% of dogs underwent formal response assessment and only five dogs had a cardiac presentation.

由于肿瘤的位置和性质，手术活检通常是这些患者的不利选择，临床医生必须整合对患者信号和品种风险、临床表现和超声心动图结果的了解，以推断心脏 HSA 的“推定诊断”，而不是组织病理学。显然，本研究中涉及的场景代表了临床兽医肿瘤学中常见的诊断和治疗困境，尽管没有纳入组织病理学诊断的黄金标准，但必须进行评估，以便为临床医生提供合理的治疗选择这种具有挑战性的癌症。本研究的目的是描述接受 DOX 化疗的狗对可测量的推定心脏 HSA 的反应率和无进展生存期 （PFS），确定影响结果的预后因素，并将接受治疗的狗的结果与大量未经治疗的当代对照 （CTL） 的结果进行比较。假设是接受化疗的狗比不接受治疗的狗经历了更长的生存时间。

Since surgical biopsy is usually an unfavourable option in these patients owing to location and nature of the tumour, clinicians must integrate knowledge of the patient's signalment and breed risk, clinical presentation and echocardiographic findings to deduce a ‘presumptive diagnosis’ of cardiac HSA in lieu of histopathology. Clearly, the scenario addressed in this study represents a common diagnostic and therapeutic dilemma in clinical veterinary oncology, and one that although not incorporating the gold standard of histopathologic diagnosis, must be evaluated in order to provide clinicians with reasonable therapeutic options for this challenging cancer. The purposes of this study were to describe the response rate and progression-free survival (PFS) of dogs receiving DOX chemotherapy for measureable presumptive cardiac HSA, identify prognostic factors influencing outcome and compare outcomes of treated dogs with those of a large cohort of untreated contemporary controls (CTLs). The hypothesis was that dogs receiving chemotherapy experienced longer survival times than dogs not receiving treatment.

3 材料与方法 (Materials and methods)

3.1 患者群体 (Patient population)

评估了 8 年（2005-2013 年）在单个兽医转诊中心（红岸兽医医院）就诊的推定心脏 HSA 的狗的医疗记录，以确定符合条件的患者。纳入本研究的标准如下：根据位置（右心房、右耳廓、房室沟、房室或三尖瓣、无心室壁）和/或异质性或空腔超声外观，强烈怀疑为 HSA 的原发性心脏肿瘤;至少进行一次完整的超声心动图检查;以及充分的随访信息，以便进行结果分析。排除显示回声特征或更提示化疗瘤或其他非血管性心脏肿瘤的解剖位置的肿瘤。如果狗因心脏肿瘤而接受手术干预（切除或心包切除术），则不包括在内。诊断时有转移的影像学或超声学证据的患者符合纳入条件。根据业主的意愿决定使用DOX进行全身治疗;然而，所有纳入的患者都接受了肿瘤科医生的会诊。

Medical records of dogs presenting for presumed cardiac HSA at a single veterinary referral centre (Red Bank Veterinary Hospital) over an 8-year period (2005–2013) were evaluated to identify eligible patients. Criteria for inclusion in this study were as follows: a primary cardiac tumour strongly suspected to be HSA based on the location (right atrium, right auricle, AV groove, AV or tricuspid valve, ventricular-free wall) and/or heterogeneous or cavitated ultrasonographic appearance; at least one full echocardiogram performed; and adequate follow-up information to allow for outcome analysis. Tumours displaying echogenic characteristics or an anatomic location more suggestive of a chemodectoma or other non-vascular cardiac tumour were excluded. Dogs were not included if they underwent surgical intervention (either resection or pericardiectomy) for their cardiac tumour. Patients with radiographic or ultrasonographic evidence of metastasis at diagnosis were eligible for inclusion. The decision to pursue systemic treatment with DOX was made according to owner preference; however, all included patients underwent consultation with an oncologist.

从病历中获得的信息包括品种;年龄;性;重量;初次就诊和诊断的日期;提出投诉;分期试验的结果;超声心动图结果包括肿瘤大小、是否存在心包填塞、进行的心包穿刺次数、是否进行治疗、化疗方案、治疗反应、治疗相关不良事件 （AE）、死亡日期和尸检结果（如果进行）。病历中没有的随访信息是通过与主人和/或转诊兽医的电话联系获得的。使用上述方法跟踪所有狗，直到死亡或失去联系。

Information obtained from the medical records included breed; age; sex; weight; date of initial presentation and diagnosis; presenting complaint; results of staging tests; echocardiogram findings including size of tumour, the presence of tamponade, the number of pericardiocenteses performed, whether treatment was pursued, chemotherapy protocol, treatment response, treatment-related adverse events (AEs), date of death and necropsy results if performed. Follow-up information not available in the medical record was obtained over telephone contact with owners and/or referring veterinarians. All dogs were followed until the time of death or loss of contact using the above methods.

3.2 诊断性检查 (Diagnostic workup)

记录诊断时进行的分期检查结果，包括自动全血细胞计数 （CBC）、血清生化特征、胸部 X 线摄影和腹部超声检查。仅接受腹部超声或胸部 X 光检查的狗被认为是部分分期的，而同时接受腹部超声和胸部 X 光检查的狗被认为是完全分期的。记录了提示转移性肿瘤（充满液体或空洞的结节/肿块）的影像学和超声变化。还记录了心电图和超声心动图的结果。使用超声心动图测量基线原发性肿瘤大小。所有超声心动图均使用单板认证的心脏病专家 （CDS） 进行评估。

Results of staging tests performed at diagnosis were recorded, including automated complete blood count (CBC), serum biochemical profile, thoracic radiography and abdominal ultrasonography. Dogs undergoing only an abdominal ultrasound or thoracic radiographs were considered partially staged, while dogs that had both an abdominal ultrasound and thoracic radiographs were considered fully staged. Radiographic and ultrasonographic changes suggestive of metastatic neoplasia (fluid-filled or cavitated nodules/masses) were documented. Findings from electrocardiography and echocardiography were also recorded. Baseline primary tumour size was measured using echocardiography. All echocardiograms were evaluated using a single board-certified cardiologist (CDS).

3.3 治疗剂量和时间表 (Treatment dosing and schedule)

接受治疗的狗接受单药化疗方案，包括 DOX（狗 1 mg/kg <10 kg，狗 30 mg/m^2 >10 kg），每 2-3 周静脉输注一次。狗继续接受治疗，直到检测到疾病进展或完成计划的方案，通常包括至少五次总治疗。如果主治临床医生认为合适，狗可以接受超出计划方案的额外剂量的 DOX。一组未接受化疗的当代狗（提交给同一机构）被用作 CTL 人群。接受DOX的狗的主人被提供口服抗恶心药物（maropitant，2mg/kg PO，每天一次），以备不时之需。

Dogs undergoing treatment received a single-agent chemotherapy protocol consisting of DOX (1 mg/kg for dogs <10 kg, 30 mg/m^2 for dogs >10 kg) given once every 2–3 weeks by intravenous infusion. Dogs continued to receive treatments until disease progression was detected or the planned protocol, typically consisting of a minimum of five total treatments, was completed. Dogs could receive additional doses of DOX beyond the planned protocol if deemed appropriate by the attending clinician. A contemporary group of dogs (presented to the same institution) not undergoing chemotherapy was used as a CTL population. Owners of dogs receiving DOX were provided oral anti-nausea medication (maropitant, 2 mg kg−1 PO once daily) for use as needed.

3.4 其他治疗 (Other treatments)

在计划的 DOX 方案完成后或在疾病进展的情况下，狗可以继续使用替代或抢救性化疗方案。一些狗接受了节律化疗的维持治疗，其中一部分在 DOX 方案期间启动了这种治疗。如果适用，记录了对非心脏疾病部位进行的治疗。

Following the completion of the planned DOX protocol or in the event of disease progression, dogs could continue with alternative or rescue chemotherapeutic protocols. Some dogs received maintenance therapy with metronomic chemotherapy, with a subset initiating this therapy during the DOX protocol. Treatments administered for non-cardiac sites of disease were recorded, if applicable.

3.5 AE 的评估、反应和结果 (Evaluation of AEs, response and outcome)

业主在每次就诊时完成书面问卷（图1），以报告胃肠道和其他不良事件。所有接受治疗的狗在每次使用 DOX 治疗之前都进行了 CBC，偶尔在治疗后 7 天进行。根据 VCOG-CTCAE 1.1.29 对治疗相关的 AE 进行分级

Owners completed written questionnaires (Fig. 1) at each visit to report gastrointestinal and other AEs. All treated dogs had a CBC performed before each treatment with DOX and occasionally at the 7-day mark after treatment. Treatment-related AEs were graded according to the VCOG-CTCAE 1.1.29

在每个治疗日和随访中对狗进行体格检查。所有接受 DOX 治疗的狗在第二次预定剂量的 DOX 之前立即接受了超声心动图的初步反应评估。根据 RECIST 1.1 指南30 进行反应评估，其中完全反应 （CR） 包括肿瘤完全消失;部分缓解 （PR） 包括最长肿瘤直径至少减少 30%;进行性疾病 （PD） 包括最长肿瘤直径至少增加 20%、出现转移性病变或提示疾病进展的临床体征（心包积液、腹腔积血和相关后遗症）;稳定疾病 （SD） 既没有充分的消退来符合 PR 的条件，也没有足够的进展来符合 PD 的条件。 建议在初始反应评估后每隔一次治疗就诊时进行超声心动图检查，以确认持续的反应并检测肿瘤进展。在第一次反应评估（第二次 DOX 剂量之前）检测到的 SD 必须至少持续到第二次反应评估时（每 2 次接受 DOX 的狗从治疗开始之日起 6 周，每 3 周接受一次 DOX 的狗从治疗开始之日起 9 周）才能被认为是真正的 SD。

Dogs were assessed with physical examinations on every treatment day and follow-up visit. All dogs receiving treatment with DOX underwent an initial response assessment with echocardiogram immediately before their second scheduled dose of DOX. Response assessment was made based on RECIST 1.1 guidelines,30 where complete response (CR) consisted of complete disappearance of the tumour; partial response (PR) consisted of at least a 30% reduction in longest tumour diameter; progressive disease (PD) consisted of at least a 20% increase in longest tumour diameter, the appearance of metastatic lesions, or clinical signs suggestive of disease progression (pericardial effusion, hemoperitoneum and related sequelae); and stable disease (SD) consisted of neither sufficient regression to qualify for PR nor sufficient progression to qualify for PD. Echocardiograms were recommended to be performed at every other treatment visit after the initial response assessment to confirm ongoing response and to detect tumour progression. SD detected at the first response assessment (before the second dose of DOX) had to be sustained at least until the time of the second response assessment (6 weeks from the time of treatment initiation in dogs receiving DOX every 2 and 9 weeks from treatment initiation for dogs receiving DOX every 3 weeks) in order to be considered true SD.

主要结局终点是PFS和总生存期（OS）。对所有接受至少一次 DOX 治疗的狗进行 PFS 评估，并计算从治疗开始到疾病进展或任何原因死亡的时间。如果狗在随访中丢失或在数据收集时没有疾病进展仍然活着，则从PFS分析中删失。对两个人群的OS进行了评估，并计算为从诊断到疾病进展死亡的时间。如果狗在随访中丢失，死于与肿瘤无关的原因，或者在数据收集时还活着，则从OS分析中剔除。

The primary outcome endpoints were PFS and overall survival (OS). PFS was assessed for all dogs receiving at least one DOX treatment session and was calculated as the time from treatment initiation to disease progression or death from any cause. Dogs were censored from PFS analysis if they were lost to follow-up or still alive without disease progression at the time of data collection. OS was assessed for both populations and was calculated as the time from diagnosis to death from disease progression. Dogs were censored from OS analysis if they were lost to follow-up, died from causes unrelated to the tumour, or were still alive at the time of data collection.

3.6 统计分析 (Statistical analysis)

使用分类变量（例如品种、性别、转移的存在和分期程序）的 Fischer 精确检验和连续变量（例如体重、年龄）的不配对 t 检验进行组比较（DOX 治疗组与未治疗组）。

PFS 和 MST 使用 Kaplan-Meier 乘积极限法计算。在DOX治疗组中，检查与狗的PFS和OS预后因素相关的变量包括体重，诊断时是否存在转移，诊断时贫血，诊断时血小板减少症，诊断时心电图异常，诊断时填塞，肿瘤位置，肿瘤大小（平均值和中位数），进行心包穿刺术的次数，DOX剂量（30mg m-2 vs 1 mg kg-1）， DOX 时间表（每 2 周一次与每 3 周一次）、同时使用节律化疗、使用抢救疗法（仅适用于 OS）和对治疗的反应。使用两个数据集的对数秩 （Mantel-Cox） 检验和趋势的对数秩检验（当输入两个以上数据集时）比较生成的生存曲线，并报告双尾 P 值。P 值为 ≤0.05 被认为是显著的。所有统计分析均使用商业软件包（Prism v5.0，GraphPad Software，LaJolla，CA，USA）进行。

Group comparisons (DOX-treated versus untreated groups) were made using Fischer’s exact test for categorical variables (e.g. breed, sex, presence of metastasis and staging procedures) and the unpaired t-test for continuous variables (e.g. weight, age).

The PFS and MST were calculated using the Kaplan–Meier product-limit method. Variables examined for association as prognostic factors for PFS and OS for dogs in the DOX-treated group included body weight, presence of metastasis at diagnosis, anaemia at diagnosis, thrombocytopenia at diagnosis, ECG abnormalities at diagnosis, tamponade at diagnosis, tumour location, tumour size (mean and median), number of pericardiocenteses performed, DOX dose (30 mg m−2 versus 1 mg kg−1), DOX schedule (every 2 weeks versus every 3 weeks), concurrent use of metronomic chemotherapy, use of rescue therapy (for OS only) and response to treatment. Generated survival curves were compared using the log-rank (Mantel–Cox) test for two data sets and the log-rank test for trend (when more than two datasets were entered) with two-tailed P values reported. A P value of ≤0.05 was considered significant. All statistical analyses were performed using a commercial software package (Prism v5.0, GraphPad Software, LaJolla, CA, USA).

4 结论 (Results)

4.1 心电图学 (Electrocardiography)

DOX 治疗组中有 24 只 （38%） 在初次就诊时进行了心电图检查，18 只 （75%） 观察到异常，包括加速的脑室心律 （n = 8）、室性早产复合体 （n = 7）、窦性心动过速 （n = 3）、室性心动过速 （n = 2） 和房室传导阻滞 （n = 1）。CTL 组中有 39 只狗 （51%） 在就诊时进行了心电图检查，29 只狗 （74%） 注意到异常，包括加速的脑室节律 （n = 12）、室性早产复合体 （n = 11）、窦性心动过速 （n = 5）、室性心动过速 （n = 2）、电交替 （n = 3） 和窦性心律失常 （n = 2）。

Twenty-four dogs (38%) in the DOX-treated group had an ECG performed at initial presentation and 18 (75%) had abnormalities noted, including accelerated idioventricular rhythm (n = 8), ventricular premature complexes (n = 7), sinus tachycardia (n = 3), ventricular tachycardia (n = 2) and atrioventricular block (n = 1). Thirty-nine dogs (51%) in the CTL group had an ECG performed at presentation and 29 dogs (74%) had abnormalities noted, including accelerated idioventricular rhythm (n = 12), ventricular premature complexes (n = 11), sinus tachycardia (n = 5), ventricular tachycardia (n = 2), electrical alternans (n = 3) and sinus arrhythmia (n = 2).

4.2 超声心动图 (Echocardiography)

所有 140 只狗都至少进行了一次超声心动图检查。DOX治疗组进行的超声心动图的中位数为4次（范围为1-10）。DOX 治疗组中有 58 只狗 （91%） 在就诊时有心包填塞的超声心动图证据。肿块位于32只狗的右耳/心耳（50%），28只狗的右心房（44%），2只狗的右心室流出道（3%）和2只狗的右房室沟（3%）。DOX治疗组的55只狗（86%）进行了肿瘤测量，平均最长直径为3.7厘米（中位数为3.25;范围为2-8厘米）。CTL组的超声心动图中位数为2（范围为1-7）。CTL 组中有 71 只狗 （93%） 在就诊时有心包填塞的超声心动图证据。肿块位于36只狗的右心房（47%），25只狗的右耳/心耳（31%），5只狗的右房室沟（6%），4只狗的主动脉和左心房之间（5%），3只狗的三尖瓣（4%），3只狗的右心房和主动脉之间（4%），1只狗的左心室无壁（1%）。CTL组中有59只狗（78%）的肿瘤测量值，平均最长直径为3.4厘米（中位数为3.5;范围为1-8厘米）。

All 140 dogs had at least one echocardiogram performed. The median number of echocardiograms performed in the DOX-treated group was four (range, 1–10). Fifty-eight dogs (91%) in the DOX-treated group had echocardiographic evidence of tamponade at presentation. The mass was located in the right auricle/atrial appendage in 32 dogs (50%), right atrium in 28 dogs (44%), right ventricular outflow tract in 2 dogs (3%) and right atrioventricular groove in 2 dogs (3%). Tumour measurements were available for 55 dogs (86%) in the DOX-treated group, and the mean longest diameter was 3.7 cm (median, 3.25; range, 2–8 cm). The median number of echocardiograms in the CTL group was 2 (range, 1–7). Seventy-one dogs (93%) in the CTL group had echocardiographic evidence of tamponade at presentation. The mass was located in the right atrium in 36 dogs (47%), right auricle/atrial appendage in 25 dogs (31%), right atrioventricular groove in 5 dogs (6%), between the aorta and left atrium in 4 dogs (5%), tricuspid valve in 3 dogs (4%), between the right atrium and aorta in 3 dogs (4%), and in the left ventricular-free wall in 1 dog (1%). Tumour measurements were available for 59 dogs (78%) in the CTL group, and the mean longest diameter was 3.4 cm (median, 3.5; range, 1–8 cm).

在DOX治疗组的58只狗（91%）中进行了心包穿刺术。该组的平均心包穿刺次数为 2 例（中位数为 1;范围为 0-8）。CTL组对69只狗（91%）进行了心包穿刺术。该组的平均心包穿刺次数为1例（中位数为1;范围为0-3）。

Pericardiocentesis was performed in 58 dogs (91%) in the DOX-treated group. Mean number of pericardiocenteses for this group was 2 (median, 1; range, 0–8). Pericardiocentesis was performed in 69 dogs (91%) in the CTL group. Mean number of pericardiocenteses for this group was 1 (median, 1; range, 0–3).

4.3 治疗 (Treatment)

DOX 方案 (DOX protocol)

在DOX治疗组中，总共对64只狗施用了232剂DOX。每只狗的平均DOX剂量为4（中位数为4;范围为1-9）。九只狗接受了超过 5 剂的 DOX，最大剂量为 9 剂。58 只 （91%） 狗以 30 mg/m^2 剂量治疗，6 只狗 （9%） 以 1 mg/kg 剂量治疗。56 只狗 （88%） 每 2 周接受治疗一次，6 只狗 （9%） 每 3 周接受治疗;没有 2 只狗的治疗时间表信息。

A total of 232 doses of DOX were administered to 64 dogs in the DOX-treated group. The mean number of DOX doses per dog was 4 (median, 4; range, 1–9). Nine dogs received more than 5 doses of DOX and the maximum number of doses administered was 9. Fifty-eight (91%) dogs were treated at the 30 mg m−2 dose and 6 dogs (9%) were treated at 1 mg kg−1. Fifty-six dogs (88%) received treatment every 2 weeks and six dogs (9%) were treated every 3 weeks; treatment schedule information was not available for 2 dogs.

响应者的并发和后续协议 (Concurrent and subsequent protocols for responders)

11 只狗 （17%） 开始同时进行节拍化疗，包括环磷酰胺（12.5-15 mg/m^2 PO q/24）和非甾体抗炎药在 DOX 方案的前三个周期的某个时间点。14 只狗 （22%） 在完成 DOX 方案或至少四个 DOX 周期后接受节拍化疗。一只狗在完成 DOX 治疗后每周接受长春新碱（0.5 mg/m^2 IV）和标准剂量环磷酰胺（250 mg/m^2 PO，分 3 天）维持治疗。

Eleven dogs (17%) began concurrent metronomic chemotherapy, consisting of cyclophosphamide (12.5–15 mg/m^2 PO q per 24) and a non-steroidal anti-inflammatory drug at some point during the first three cycles of DOX protocol. Fourteen dogs (22%) were treated with metronomic chemotherapy after the completion of their DOX protocols or following at least four cycles of DOX. One dog underwent maintenance treatment with vincristine (0.5 mg m−2 IV), and standard dose cyclophosphamide (250 mg m−2 PO divided over 3 days) given on a weekly basis upon completion of treatment with DOX.

救援协议 (Rescue protocols)

23 只狗 （36%） 在 DOX 化疗失败后接受了抢救方案治疗。使用的抢救方案包括长春新碱/环磷酰胺 （n=14）、节律化疗 （n=2）、长春碱/环磷酰胺 （n=3）、长春新碱 （n=2） 和卡铂 （n=1）。一只狗接受了另一种剂量的 DOX 治疗，因为在初始 DOX 方案完成 90 天后，狗在接受节拍化疗时发生了复发。

Twenty-three dogs (36%) were treated with a rescue protocol after failing DOX chemotherapy. Rescue protocols used included vincristine/ cyclophosphamide (n=14), metronomic chemotherapy (n=2), vinblastine/cyclophosphamide (n=3), vincristine (n=2) and carboplatin (n=1). One dog was treated with another dose of DOX, as relapse occurred while the dog was being treated with metronomic chemotherapy 90 days after the completion of the initial DOX protocol.

其他治疗 (Other treatments)

DOX治疗组中的三只狗（5%）接受了其他病变的手术治疗，包括两只接受脾切除术的狗和一只接受肝叶切除术的狗。

Three dogs (5%) in the DOX-treated group underwent surgical treatment for additional lesions, including two dogs that underwent splenectomy and one dog that underwent a liver lobectomy.

4.4 不良事件 (Adverse events)

表 3 列出了与 DOX 相关的 AE。报告了 16 例血液学毒性和 56 例胃肠道毒性。报告了 5 例 IV 级中性粒细胞减少症发作，但均在临床上无症状。一只狗发烧，但这与中性粒细胞减少事件无关。胃肠道毒性通常为轻度至中度，仅报告IV级厌食和呕吐各一次。

AEs associated with DOX are listed in Table 3. Sixteen hematologic and fifty-six gastrointestinal toxicities were reported. Five episodes of Grade IV neutropenia were reported, but all were clinically silent. One dog experienced a fever, but this was not associated with a neutropenic event. Gastrointestinal toxicities were generally mild to moderate with only one episode each of Grade IV anorexia and vomiting reported.

4.5 治疗后的反应和结果 (Response and outcome following therapy)

接受DOX治疗的64只狗（100%）有可供分析的结果信息，这些数据总结在表4和表5中。一只狗没有接受预定的反应评估超声心动图，因此没有相关的反应信息;但是，提供了这只狗的生存数据。客观缓解率为41%，生物缓解率（CR+PR+SD）或临床获益为68%。20 只狗 （32%） 对 DOX 治疗没有反应。图 2 和 3 分别显示了 DOX 治疗犬的 PFS 和 DOX 和 CTL 组犬的 OS 的 Kaplan-Meier 生存概率曲线。在确定PFS之前，有三只狗失去了随访，因此从该分析中被删失。在确定 OS 之前，有 6 只狗丢失了随访，另外 4 只狗死于与 HSA 无关的原因;这 10 只狗从操作系统分析中被删失。DOX治疗组狗的PFS和MST分别为66天和116天。未经治疗的 CTL 犬的 MST 为 12 天。

Sixty-four dogs (100%) undergoing treatment with DOX had outcome information available for analysis, and these data are summarized in Tables 4 and 5. One dog did not undergo the scheduled response assessment echocardiogram and thus did not have associated response information available; however, survival data are provided for this dog. The objective response rate was 41%, and the biologic response rate (CR+PR+SD), or clinical benefit, was 68%. Twenty dogs (32%) failed to respond to treatment with DOX. Kaplan–Meier survival probability curves illustrating PFS for DOX-treated dogs and OS for dogs in both the DOX and CTL groups are presented in Figs 2 and 3, respectively. Three dogs were lost to follow-up before PFS could be determined and were thus censored from this analysis. Six dogs were lost to follow-up before OS could be determined and an additional four dogs died from causes unrelated to HSA; these 10 dogs were censored from OS analysis. The PFS and MST for dogs in the DOX-treated group were 66 and 116 days, respectively. The MST for untreated CTL dogs was 12 days.

4.6 变量作为预后因素 (Variables as prognostic factors)

分析的与PFS和OS相关的变量分别列于表6/表S1，支持信息和表7/表S2。通过单因素分析，诊断时存在血小板减少症 （P =0.022） 且肿瘤大小大于中位数 （P =0.013） 或平均 （P =0.001） 最长直径与 PFS 降低显著相关。诊断时存在血小板减少症也与OS降低显著相关（P=0.034）。对于DOX治疗组的狗，诊断时存在转移与PFS（P = 0.591）或OS（P = 0.56）的降低没有显着相关性，尽管没有转移的治疗狗有更长寿的趋势。全分期（MST=114 d）、部分分期（MST=94 d）或无分期（MST=139 d）治疗犬组的OS差异无统计学意义，P=0.10。在接受同步节拍治疗的狗和未同时接受节拍疗法的狗之间没有发现 PFS 或 MST 的统计学差异。DOX剂量（30mg m-2 vs 1 mg kg-1）和给药频率（每2周与每3周一次）与PFS或OS无关。

Variables analysed for association with PFS and OS are presented in Table 6/Table S1, Supporting Information, and Table 7/Table S2, respectively. By univariate analysis, the presence of thrombocytopenia (P =0.022) at diagnosis and tumour size greater than the median (P =0.013) or mean (P =0.001) longest diameter were significantly associated with decreased PFS. The presence of thrombocytopenia at diagnosis was also significantly associated with decreased OS (P =0.034). For dogs in the DOX-treated group, the presence of metastasis at diagnosis was not significantly associated with decreased PFS (P =0.591) or OS (P =0.56), although there was a trend for treated dogs without metastasis to live longer. There was no significant difference in OS between groups of treated dogs that underwent full staging (MST=114 days), partial staging (MST=94 days),or no staging (MST=139 days), P =0.10. No statistical difference in PFS or MST was found between dogs receiving and those not receiving concurrent metronomic therapy. DOX dosage (30 mg m−2 versus 1 mg kg−1) and administration frequency (every 2 weeks versus every 3 weeks) were not associated with PFS or OS.

4.7 尸检 (Necropsy)

DOX治疗组中的三只狗进行了尸检。组织病理学证实所有三只狗都存在右心房 HSA。脾脏HSA也在一只狗中得到证实。

Three dogs in the DOX-treated group had a necropsy performed. Histopathology confirmed the presence of right atrial HSA in all three dogs. Splenic HSA was also confirmed in one dog.

5 讨论 (Discussion)

本研究针对执业肿瘤学家经常遇到的临床情况，其中患者被推定为心脏 HSA。尽管通过手术干预获得组织学诊断被认为是大多数实体瘤的金标准方法，但对于这种肿瘤通常不可行，因此临床医生面临着在没有明确组织诊断的情况下治疗可测量肿瘤的挑战。本研究的设计纳入了一组同时未经治疗的 CTL，虽然不完美，但可以相对公平地评估 DOX 化疗为该患者群体提供的潜在生存益处。与未经治疗的 CTL 相比，接受 DOX 化疗治疗推定心脏 HSA 的狗的生存率显着提高。然而，中位PFS（66天）和MST（116天）仍然相对较短，只有14%的接受治疗的狗有可能存活超过6个月。

This study addresses a clinical situation commonly encountered by the practising oncologist, in which a patient presents with a presumptive diagnosis of cardiac HSA. Although obtaining a histologic diagnosis via surgical intervention is considered the gold standard approach for most solid tumours, it is often not feasible for this tumour, thus leaving the clinician with the challenge of treating a measureable tumour without a definitive tissue diagnosis. The design of this study, which incorporates a group of contemporaneous untreated CTLs, while imperfect, allows for a relatively evenhanded evaluation of the potential survival benefit offered by DOX chemotherapy for this patient population. Dogs undergoing DOX chemotherapy for presumptive cardiac HSA had significantly improved survival compared with untreated CTLs. However, the median PFS (66 days) and MST (116 days) still remain relatively short, with only 14% of treated dogs having a probability of surviving beyond 6 months.

在这项研究中，对治疗的反应对于确定生存时间很重要，与那些没有反应的狗相比，那些经历临床益处的狗享有显着更长的 PFS 和 MST。客观缓解率与先前报道的接受化疗的可测量非心脏 HSA 的缓解率相当.26， 27 生物反应率或临床获益为 68%，并且将 SD 作为阳性结果是评估具有挑战性的癌症（如心脏 HSA）治疗方案的重要考虑因素。对于这种肿瘤类型，一旦最初的紧急事件消退，大多数狗都会迅速恢复，无论是否进行心包穿刺术。因此，即使没有达到可测量的肿瘤反应，在没有进一步发生心包积液和心包填塞的情况下保持良好的生活质量，对于大多数患者群体来说仍然是一个积极的结果。重要的是，在这项研究中，所有被认为患有 SD 的狗都必须持续这种反应，直到第二次超声心动图反应评估（至少 6 周）时。七只狗持续超声检查确认的 SD >100 天。由于一些狗 （n = 6） 每 3 周而不是每 2 周进行一次 DOX，因此正在进行的反应评估超声心动图的时间并不完全标准化，并且代表了回顾性研究的固有缺陷。此外，在一剂化疗后进行初始反应评估的时间可能不是每个执业肿瘤学家的惯例，因为许多临床医生更喜欢在判断治疗效果之前进行两到三剂治疗。理想的反应评估方案可能包括在每次治疗就诊时进行超声心动图检查，以便对患者反应充满信心;然而，在临床实践中，这通常是一种成本过高的措施。此外，由于肿瘤测量可能存在一些差异，具体取决于存在的心包积液量，因此在未来的前瞻性研究中考虑将心脏门控 MRI 或 CT 扫描作为肿瘤测量工具可以提高反应评估的精确度，尽管这些方式所需的重复麻醉事件和增加的财务承诺在该患者群体中可能是不可取的。

In this study, response to therapy was important in determining the duration of survival, where those dogs that experienced clinical benefit enjoyed significantly longer PFS and MST compared with those dogs not experiencing a response. The objective response rate was comparable with those previously reported for measureable non-cardiac HSA treated with chemotherapy.26, 27 The biologic response rate, or clinical benefit, was 68%, and the inclusion of SD as a positive outcome is an important consideration in the evaluation of a treatment protocol for a challenging cancer such as cardiac HSA. With this tumour type, most dogs recover quickly once the initial emergent event subsides, with or without pericardiocentesis. Thus, maintenance of a good quality of life without further episodes of pericardial effusion and cardiac tamponade, even without achievement of a measureable tumour response, is still a positive outcome for the majority of this patient population. Importantly, all dogs deemed to have SD in this study must have sustained that response until the time of the second echocardiographic response assessment (minimum of 6 weeks). Seven dogs sustained ultrasonographically confirmed SD for >100 days. Because some dogs (n = 6) were administered DOX every 3 weeks instead of every 2 weeks, the timing of ongoing response assessment echocardiograms was not exactly standardized and represents an inherent shortcoming of a retrospective study. Furthermore, the timing of the initial response assessment just after one dose of chemotherapy may not be a convention for every practising oncologist, as many clinicians prefer to administer two or three doses of treatment before making a judgement on the efficacy of a therapy. An ideal response assessment protocol might include an echocardiogram at each treatment visit in order to be confident in patient response; however, this is typically a cost-prohibitive measure in clinical practice. Additionally, as there could be some variability in tumour measurement depending on how much pericardial fluid is present, the consideration of cardiac-gated MRI or CT scan as tumour measurement tools in a future prospective study could improve the precision of response assessments, although the repeated anaesthetic events and increased financial commitment required for these modalities may be undesirable in this patient population.

AE 通常为轻度，与先前报道的与 DOX 治疗相关的 AE 一致。没有狗经历过危及生命的AE。血小板减少症的存在与接受心脏 HSA DOX 化疗的狗的存活率降低有关。对这一发现的可能解释可能是，这些狗正在经历弥散性血管内凝血，这是 HSA31、32 的已知并发症，因此本质上处于更受损的临床位置。血小板减少症在直觉上也与肿瘤出血有关，可能代表更大、更脆弱的肿瘤;鉴于肿瘤大小较大也与生存率下降有关，这一推理似乎是合理的。然而，只有 67% 的狗进行了 CBC;因此，这些推论并非基于整个研究人群。此外，未进行手动血片评估以确认血小板减少症;因此，不能排除血小板聚集引起的人为血小板减少的可能性。因此，如果所有狗都接受全血细胞计数和手动血小板计数，血小板减少症是否仍将是阴性预后指标，可能存在一些问题。这项研究中的数字太小，无法使多变量分析具有统计学意义。

AEs were typically mild and consistent with previously reported AEs related to DOX therapy. There were no dogs that experienced life-threatening AEs. The presence of thrombocytopenia was associated with decreased survival for dogs undergoing DOX chemotherapy for cardiac HSA. A possible explanation for this finding may be that these dogs were experiencing disseminated intravascular coagulation, a known complication of HSA31, 32 and as such were inherently in a more compromised clinical position. Thrombocytopenia is also intuitively related to tumour haemorrhage and could possibly be representative of larger and more fragile tumours; in the light of the finding that larger tumour size was also associated with decreased survival, this reasoning seems plausible. However, only 67% of dogs had a CBC performed; thus, these inferences are not based on the entire study population. Furthermore, manual blood film evaluations were not performed to confirm thrombocytopenia; therefore, the possibility of artifactual thrombocytopenia due to platelet clumping cannot be ruled out. Therefore, there may be some question as to whether thrombocytopenia would remain a negative prognostic indicator had all dogs undergone a CBC with manual platelet count. Numbers in this study were too small to make multivariate analysis statistically meaningful.

这项研究的局限性源于其回顾性，它排除了分期的标准化和将狗随机分配到治疗组或非治疗组。具体来说，在进行的分期测试以及随后每组转移的狗的数量方面，各组之间存在显着差异。然而，DOX治疗组包含更多患有转移性疾病的狗，降低了治疗组中低阶段狗的选择偏倚机会，但并没有消除这种可能性，因为CTL组中完全分期的狗较少，而CTL狗明显更多根本没有分期。这种差异很可能反映了业主在已经有动力进行化疗时进行诊断的意愿，并说明了客户对治疗侵袭性癌症（如心脏HSA）的看法存在潜在偏差。具体来说，拒绝化疗的所有者，可能部分是因为整体预后，可能更倾向于更早地寻求安乐死，这种偏倚可能影响了OS中注意到的差异。 理想情况下，治疗组和CTL组都将接受类似的PFS随访和记录，以进一步消除这种偏倚。尽管一部分狗也同时或在 DOX 方案之后接受了节拍化疗，但这组狗的 PFS 或 OS 没有显着差异;因此，使用节拍化疗并没有给这组患者带来生存优势。此外，接受抢救治疗的狗（n = 23）的OS有缩短的趋势（74天 vs 139天），尽管这种差异并不显着（P = 0.1243），并且很可能代表DOX治疗的早期治疗失败和随后对救援治疗没有反应。

A limitation of this study stems from its retrospective nature, which precluded the standardization of staging and the randomization of dogs to treatment or non-treatment groups. Specifically, there was a significant difference between groups with respect to staging tests performed and subsequently the number of dogs with metastasis in each group. However, the DOX-treated group contained a larger number of dogs with metastatic disease, decreasing the chance of selection bias for lower stage dogs in the treated group but not eliminating this possibility, as fewer dogs in the CTL group were fully staged and significantly more CTL dogs underwent no staging at all. This difference most likely reflects a willingness of owners to perform diagnostics when already motivated to pursue chemotherapy and speaks to potential bias of client perspectives for treating an aggressive cancer such as cardiac HSA. Specifically, owners who declined chemotherapy, presumably in part because of overall prognosis, may be more inclined to seek euthanasia earlier, and this bias may have impacted differences noted in OS. Ideally, both treatment and CTL groups would have been subjected to similar follow-up and documentation of PFS in order to further eliminate such bias. Although a subset of dogs also received metronomic chemotherapy either concurrent or subsequent to the DOX protocol, there was no significant difference in PFS or OS for this group of dogs; thus, the use of metronomic chemotherapy did not confer a survival advantage to this group of patients. Additionally, dogs receiving rescue therapy (n = 23) had a trend towards shorter OS (74 versus 139 days), although this difference was not significant (P = 0.1243) and most likely represents an early treatment failure on DOX therapy and subsequent failure to respond to rescue therapy.

另一个局限性是本研究中缺乏对狗的组织学诊断，所有这些都是基于心脏 HSA 的推定诊断而包括的。患有其他肿瘤类型的狗，可能具有较少的攻击性生物学行为和优越的生存时间，可能已被纳入该患者群体。此外，根据影像学和超声学特征推测与转移一致的病变实际上可能代表良性变化。同样，一些推测的转移性病变可能是原发性肿瘤，并转移至心脏。无论如何，由于在该位置对肿瘤进行取样的固有困难，发现许多患者不适合进行全身麻醉和外科手术，以及与此类努力相关的费用，因此根据解剖位置、超声特征和临床病理特征确定心脏 HSA 的推定诊断应被视为接近这种常见的“现实生活”临床场景的合理方法。

Another limitation regards the lack of histologic diagnosis for dogs in this study, all of which were included based on a presumptive diagnosis of cardiac HSA. It is possible that dogs with other tumour types, potentially carrying less aggressive biologic behaviours and superior survival times, could have been included in this patient population. Furthermore, lesions that were presumed to be consistent with metastasis based on radiographic and ultrasonographic features could have actually represented benign changes. Similarly, some of the presumed metastatic lesions could have been primary tumours with metastasis to the heart. Regardless, because of the inherent difficultly in sampling tumours in this location, the finding that many patients are poor candidates for general anaesthetic and surgical procedures, and the expense associated with such endeavours, the determination of a presumptive diagnosis of cardiac HSA based on anatomic location, ultrasonographic characteristics and clinicopathologic features should be considered a reasonable method of approaching this common ‘real life’ clinical scenario.

在这项研究中，DOX 对 cHSA 的临床活性表现为客观和生物学反应率高、MST 具有统计学意义的延长以及与先前联合手术和化疗的报道相当的 OS。然而，这种疾病的生存期仍然很短，少数狗 （14%） 的生存期为 6 个月。因此，在本研究中观察到的单药 DOX 对宏观推测心脏 HSA 的任何活性都代表了结果的适度但渐进的改善。

In this study, clinical activity of DOX for cHSA is suggested by the high rate of objective and biological response, statistically significant prolongation of MST, and OS that is comparable with prior reports combining surgery and chemotherapy. However, the disease still carries a short temporal survival with a minority of dogs (14%) achieving 6-month survival. Therefore, any activity of single-agent DOX for macroscopic presumed cardiac HSA observed in this study represents a modest yet incremental improvement in outcome.

当然，手术切除肿瘤后进行辅助化疗，就像目前脾 HSA 的首选治疗方法一样，仍然是最有可能为这种肿瘤组织学的任何解剖学表现提供最长生存获益的方法。然而，可切除的心脏肿瘤的稀缺性、相关费用和尝试此类手术的固有困难可能会阻止手术切除肿瘤成为这种犬癌广泛适用的治疗方法。因此，使用基于 DOX 的方案进行全身治疗，并可能增加局部疗法，例如心包切除术甚至放射疗法，就像最近用于其他心脏基础肿瘤一样，33 可能仍然是治疗这种具有挑战性的癌症的最合理的治疗方法。一项随机前瞻性研究评估了 DOX 对心脏 HSA 联合和不联合心包切除术的施用可能是继续寻找针对这种具有挑战性的疾病表现的最佳治疗方法的一个有趣的未来方向。

Certainly, surgical tumour removal followed by adjuvant chemotherapy, as is the current treatment of choice for splenic HSA, remains the most likely approach to provide the longest survival benefit for any anatomic presentation of this tumour histology. However, the scarcity of resectable cardiac tumours, associated expense and inherent difficulty in attempting such a procedure will likely prevent surgical tumour removal from becoming a broadly applicable treatment approach for this canine cancer. Thus, systemic therapy with DOX-based protocols, with the possible addition of local therapies such as pericardiectomy or even radiation therapy, as has more recently been employed for other heart-base tumours,33 will likely remain the most rational treatment approach for this challenging cancer. A randomized prospective study evaluating the administration of DOX for cardiac HSA with and without pericardiectomy might be an interesting future direction in the continuing search for the best treatment for this challenging disease presentation.

6 确认 (Acknowledgements)

作者感谢红岸兽医医院肿瘤科的护士对本研究中评估的患者护理的贡献。

The authors acknowledge the nurses in department of oncology at Red Bank Veterinary Hospital for their contribution to the care of patients evaluated in this study.

7 Reference

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