Thyroid carcinoma develops spontaneously in dogs, with only 25% to 50% of cases amenable to surgery at diagnosis. Local control for unresectable tumours can be provided with external beam radiotherapy. The aim of this retrospective study is to describe the safety and efficacy of stereotactic body radiation therapy (SBRT) for treatment of canine thyroid carcinoma. Twenty‐three dogs met inclusion criteria; median tumour volume before SBRT was 129.9 cm³ (range, 2.7‐452.8 cm³). Sixteen patients (70%) had unresectable tumours. Pulmonary metastasis was present or suspected in 10 patients (44%) before SBRT. Patients were prescribed 15 to 40 Gy to targeted tumour volume in one to five fractions. Twenty patients evaluated had overall response rate of 70% (complete response, n = 4; partial response, n = 10). Thirteen out of sixteen (81%) symptomatic patients had clinical improvement within a median time of 16 days (range, 2‐79 days). Median progression free survival (MPFS) was 315 days. Median survival time (MST) was 362 days. Nine patients (39%) had grade 1 acute radiation toxicity. Three patients had grade 1 late radiation toxicity (two leukotrichia and one [4%] with intermittent cough). Responders had significantly longer MPFS (362 vs 90 days; HR 4.3; 95% CI 1.4‐13.5; P = .013) and MST (455 vs 90 days; HR 2.9; 95% CI 1‐8.4; P = .053). Presenting with metastasis was not a significant negative prognostic factor (MST 347 vs 348 days without metastasis; P = .352). SBRT is a safe and effective treatment modality for non‐resectable canine thyroid carcinoma.

中文翻译：

---

立体定向放疗 (SBRT) 治疗犬甲状腺癌的安全性和有效性。

甲状腺癌在狗中自发发展，只有 25% 到 50% 的病例在诊断时适合手术。外照射放疗可以对不可切除的肿瘤进行局部控制。这项回顾性研究的目的是描述立体定向放射治疗 (SBRT) 治疗犬甲状腺癌的安全性和有效性。23 只狗符合纳入标准；SBRT 前的中位肿瘤体积为 129.9 cm ³（范围，2.7-452.8 cm ³）。16 名患者 (70%) 患有不可切除的肿瘤。SBRT 前 10 名患者 (44%) 存在或怀疑存在肺转移。患者被规定为 15 到 40 Gy，以一到五个部分为目标肿瘤体积。接受评估的 20 名患者的总体反应率为 70%（完全反应，n = 4；部分反应，n = 10）。16 名（81%）有症状的患者中有 13 名（81%）在 16 天（范围，2-79 天）的中位时间内有临床改善。中位无进展生存期 (MPFS) 为 315 天。中位生存时间 (MST) 为 362 天。9 名患者 (39%) 有 1 级急性放射毒性。3 名患者出现 1 级晚期放射毒性（2 名白细胞增多症和 1 名 [4%] 间歇性咳嗽）。应答者的 MPFS 显着更长（362 天 vs 90 天；HR 4.3；95% CI 1.4-13.5；P= .013) 和 MST（455 天 vs 90 天；HR 2.9；95% CI 1-8.4；P = .053）。出现转移不是一个显着的负面预后因素（MST 347 天 vs 348 天无转移；P = .352）。SBRT 是治疗不可切除的犬甲状腺癌的一种安全有效的治疗方式。