Background Radiation-induced sarcomas (RIS) tend to have aggressive behaviour and because of their rarity, the most appropriate management for these malignancies is uncertain. Objectives Using the Canadian Sarcoma Research and Clinical Collaboration (CanSaRCC) database, a national sarcoma registry, we aimed to investigate prognostic factors and outcomes for RIS. Design Retrospective study of RIS patients treated from 1996 to 2021 at three Canadian centres. Methods RIS was defined as a sarcoma arising in a previously irradiated field following a 3+ year latency period, whose histology was distinct from the initially irradiated tumour. Clinicopathologic and treatment-related information was extracted from the CanSaRCC database. Overall survival (OS) was defined as the time from RIS diagnosis to death from any cause. Response rate (RR) to neoadjuvant chemotherapy (NACT) was based on physician assessment. Time-to-event analyses were estimated using the Kaplan-Meier method, with Cox regression for multivariate analysis. We considered a two-tailed p-value of <0.05 as statistically significant. Results One hundred seven tumours met the criteria for RIS and were divided into three subgroups: breast angiosarcoma (BAS, n = 54), osteosarcoma (OST, n = 16), and other soft-tissue sarcomas (STS, n = 37). Patients were mostly female (n = 85, 79%), treated initially for breast carcinomas (n = 54, 50.5%), and diagnosed with high-grade tumours (n = 61/71, 86%). None had evidence of synchronous metastasis. Patients with OST were younger (median age: 48 years, p < 0.001), and BAS had the shortest latency interval (8 versus 18 years for OST/STS, p < 0.001). Most patients underwent surgery, 76% (n = 76/100) R0; 24% (n = 26) received radiation therapy, mostly (n = 15, 57.7%) neoadjuvant. Among those receiving chemotherapy, 30 (75%) underwent NACT; among patients with documented response assessment, the RR was 68% (n = 17/25), being even higher in the BAS population (89.5%, n = 13/17). Median OS was 53 months (95% CI 34-101), with a 5-year OS of 47.6%; larger tumour size, high histologic grade and older age were independent prognostic factors for worse OS. Conclusion Surgery is standard, and NACT might be useful to downsize large lesions, especially in BAS patients. Raising RIS awareness is fundamental to promoting appropriate management and fostering research through multi-institutional collaborations.

中文翻译：

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放射诱发肉瘤 (RIS) 的临床人口学特征和结果：CanSaRCC 研究。

背景 放射诱发的肉瘤 (RIS) 往往具有侵袭性行为，并且由于其罕见，这些恶性肿瘤的最合适的治疗方法尚不确定。目标 使用加拿大肉瘤研究和临床合作 (CanSaRCC) 数据库（国家肉瘤登记处），我们旨在调查 RIS 的预后因素和结果。设计对 1996 年至 2021 年在加拿大三个中心接受治疗的 RIS 患者进行回顾性研究。方法 RIS 被定义为在 3 年以上潜伏期后在先前照射过的区域出现的肉瘤，其组织学与最初照射的肿瘤不同。临床病理学和治疗相关信息是从 CanSaRCC 数据库中提取的。总生存期 (OS) 定义为从 RIS 诊断到全因死亡的时间。新辅助化疗 (NACT) 的缓解率 (RR) 基于医生评估。使用 Kaplan-Meier 方法估计事件发生时间分析，并使用 Cox 回归进行多变量分析。我们认为双尾 p 值 <0.05 具有统计显着性。结果 107 例肿瘤符合 RIS 标准，分为三个亚组：乳腺血管肉瘤（BAS，n = 54）、骨肉瘤（OST，n = 16）和其他软组织肉瘤（STS，n = 37）。患者大多为女性 (n = 85, 79%)，最初接受乳腺癌治疗 (n = 54, 50.5%)，并诊断为高级别肿瘤 (n = 61/71, 86%)。没有人有同步转移的证据。OST 患者较年轻（中位年龄：48 岁，p < 0.001），BAS 的潜伏期最短（OST/STS 为 8 年，p < 0.001）。大多数患者接受了手术，76% (n = 76/100) R0；24% (n = 26) 接受放射治疗，大部分 (n = 15, 57.7%) 新辅助治疗。在接受化疗的患者中，30 人（75%）接受了 NACT；在有记录的反应评估的患者中，RR 为 68% (n = 17/25)，在 BAS 人群中甚至更高 (89.5%，n = 13/17)。中位 OS 为 53 个月 (95% CI 34-101)，5 年 OS 为 47.6%；较大的肿瘤大小、高组织学分级和年龄较大是 OS 较差的独立预后因素。结论 手术是标准手术，NACT 可能有助于缩小大病变，尤其是 BAS 患者。提高 RIS 意识对于通过多机构合作促进适当的管理和促进研究至关重要。