Canine appendicular osteosarcoma is commonly treated with limb amputation; however, limb‐sparing options are frequently desired or necessary for a subset of patients. We evaluated 123 patients and 130 sites treated with stereotactic body radiation therapy (SBRT). Eighty‐two out of 98 dogs (84%) had maximum lameness improvement at a median of 3 weeks for a median of 6 months duration. Histopathologic evaluation of available samples from amputation or necropsy revealed >80% tumor necrosis in 50% of limbs consistent with local disease control. Of evaluable patients, 41% fractured and 21% pursued an amputation after treatment. Fine needle aspirate (n = 52) and needle core biopsy (n = 28) did not result in increased fracture risk compared to those without tumor sampling (n = 50). Median survival time (MST) was 233 days and time to first event was 143 days. Gross tumor volume and planned target volume were significantly inversely associated with survival and tumor location was significantly associated with survival. Dogs with salvage amputation had a significantly longer MST compared to those without (346 vs 202 days; P = .04). The presence of metastatic disease at the time of treatment in 15 dogs did not significantly impact survival time (200 vs 237 days without metastasis; P = .58). Skin side effects correlated significantly with dose with 33% of patients with acute grade 3 effects developing consequential late grade 3 effects. While SBRT improves lameness in most patients, further investigation is needed to identify candidates with minimal early fracture risk prior to initiating therapy.

中文翻译：

---

123 只犬用立体定向放射治疗犬阑尾骨肉瘤的结果和预后

犬附肢骨肉瘤通常采用截肢治疗；然而，对于一部分患者来说，保留肢体的选择经常是需要或必要的。我们评估了接受立体定向放射治疗 (SBRT) 治疗的 123 名患者和 130 个部位。98 只狗中有 82 只（84%）在中位时间为 3 周时跛行改善最大，中位时间为 6 个月。对来自截肢或尸检的可用样本的组织病理学评估显示，50% 的肢体中 > 80% 的肿瘤坏死与局部疾病控制一致。在可评估的患者中，41% 的患者骨折，21% 的患者在治疗后进行截肢。与未进行肿瘤取样的患者（n = 50）相比，细针穿刺（n = 52）和针芯活检（n = 28）并未导致骨折风险增加。中位生存时间 (MST) 为 233 天，首次事件发生时间为 143 天。总肿瘤体积和计划目标体积与生存率显着负相关，肿瘤位置与生存率显着相关。抢救性截肢的狗的 MST 明显长于未截肢的狗（346 天 vs 202 天；P  = .04)。15 只狗在治疗时存在转移性疾病并没有显着影响生存时间（200 天对 237 天无转移；P  = .58）。皮肤副作用与剂量显着相关，33% 的急性 3 级效应患者发展为相应的晚期 3 级效应。虽然 SBRT 改善了大多数患者的跛行，但需要进一步调查以确定在开始治疗之前早期骨折风险最小的候选者。