No standard of care is currently recognized for treatment of canine prostatic carcinoma (PC). This retrospective study assesses outcome following definitive‐intent, intensity‐modulated radiation therapy (RT) in dogs with PC. Medical records review was performed, including 18 patients from four institutions undergoing definitive‐intent intensity‐modulated radiotherapy to treat PC. Diagnosis was incidental in 7/18 (39%) patients. Five dogs (28%) had evidence of metastasis to loco‐regional lymph nodes at diagnosis. Seventeen patients received concurrent non‐steroidal anti‐inflammatory drugs; 15/18 (83%) patients received maximally‐tolerated dose (MTD) chemotherapy, with variable drugs and protocols employed. Total prescribed radiation dose ranged from 48 to 54 Gy (median 50 Gy) delivered as daily doses of 2.5‐2.8 Gy. One patient was euthanized prior to completing radiotherapy. Acute toxicity was observed in nine patients; Grade 1‐2 diarrhoea was the most common toxicity observed. Suspected late toxicity (urethral stricture, ureteral stricture and hindlimb oedema) was observed in three patients. Median event‐free survival (EFS) following RT was 220 days, and median overall survival was 563 days. Local progression occurred in seven patients at a median of 241 days. Median overall survival was significantly longer in incidentally diagnosed dogs (581 vs 220 days in symptomatic dogs, P = .042). EFS was significantly longer in patients treated with MTD chemotherapy (241 vs 25 days, P < .001), and significantly shorter in patients presenting with evidence of metastatic disease (109 days) vs those without (388 days, P = .008). These findings suggest that definitive‐intent radiotherapy is a valuable treatment option for local control of canine PC with moderate risk of toxicity.

中文翻译：

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明确意图的强度调制放射治疗犬类前列腺癌：一项多机构回顾性研究。

目前尚无治疗犬前列腺癌（PC）的护理标准。这项回顾性研究评估了PC犬确定的强度调强放射治疗（RT）后的结局。进行了病历审查，包括来自四个机构的18名患者接受了明确意图的强度调制放射治疗以治疗PC。7/18（39％）患者是偶然诊断。诊断时有五只狗（28％）有转移至局部淋巴结的证据。17例患者同时接受非甾体类抗炎药；15/18（83％）患者接受了最大耐受剂量（MTD）化疗，并使用了不同的药物和方案。规定的总放射剂量范围为48至54 Gy（中值50 Gy），每日剂量为2.5-2.8 Gy。一名患者在完成放疗前被安乐死。9例患者观察到急性毒性。1-2级腹泻是观察到的最常见的毒性反应。在三名患者中发现了怀疑的晚期毒性（尿道狭窄，输尿管狭窄和后肢水肿）。放疗后的无事件生存中位数（EFS）为220天，中位总生存期为563天。7名患者发生局部进展，中位时间为241天。偶然诊断出的狗的中位总生存期明显更长（有症状的狗为581天，而有症状的狗为220天，放疗后的无事件生存中位数（EFS）为220天，中位总生存期为563天。7名患者发生局部进展，中位时间为241天。偶然诊断出的狗的中位总生存期明显更长（有症状的狗为581天，而有症状的狗为220天，放疗后的无事件生存中位数（EFS）为220天，中位总生存期为563天。7名患者发生局部进展，中位时间为241天。偶然诊断出的狗的中位总生存期明显更长（有症状的狗为581天，而有症状的狗为220天，P = .042）。MTD化疗患者的EFS明显更长（241 vs 25天，P <.001），而有转移性疾病证据的患者（109天）与未转移的患者（388天，P = .008）相比明显更短。这些发现表明，明确意图放疗是局部控制具有中等毒性风险的犬PC的宝贵治疗选择。