Background/Objectives: This multicenter retrospective study aims to evaluate the role of Ablative Radiotherapy (RT) in patients with unresectable pleural mesothelioma (PM) who experienced radiological progression after at least one line of chemotherapy, with a maximum involvement of three pleural or extrapleural sites. Methods: Adult patients (≥18 years) with PM treated with stereotactic radiotherapy between 2011 and 2022, limited to a maximum of three pleural or extrapleural sites, were included in the analysis. Ablative RT was required to be administered with radical intent. Endpoints were time to further systemic therapy (TFST), local control (LC), progression-free survival (PFS), overall survival (OS), and acute and late radiotherapy-related toxicity. Results: A total of 56 patients were identified from six Italian and one Swiss radiotherapy center. Treatment was generally well tolerated. Ten patients experienced grade 1 or 2 acute toxicity, while four patients reported persistent chest pain, with one case reaching grade 3 as late toxicity. The median TFST was 18.6 months, with TFST rates of 61.7% and 46.4% at 12 and 24 months, respectively. The median OS was 37.63 months, with 1- and 2-year OS rates of 85.2% and 65.6%. Local control was favorable (79% at 1 year), but most patients experienced disease recurrence outside the SABR treatment volume. The median disease progression-free survival (DPFS) was 8.17 months, with 1- and 2-year DPFS rates of 36% and 19%, respectively. Smoking history correlated with OS and DPFS in univariate analysis, while statistical significance for OS was maintained in multivariate analysis. Additionally, nodal status and PTV volume were associated with OS. Conclusion: SABR is a safe and effective approach for the treatment of oligorecurrent/oligoprogressive PM. The time to further systemic therapy was extended up to 18 months. At two years, 10% of patients remained disease-free, and more than half were alive at three years, suggesting a potentially indolent biological behavior in oligometastatic PM.
背景/目的：本多中心回顾性研究旨在评估消融性放疗（RT）在不可切除胸膜间皮瘤（PM）患者中的作用，这些患者在至少接受一线化疗后出现影像学进展，且受累部位最多不超过三个胸膜或胸膜外病灶。方法：研究纳入2011年至2022年间接受立体定向放疗的成年PM患者（≥18岁），病灶数量限制在最多三个胸膜或胸膜外部位。消融性放疗需以根治性目的实施。研究终点包括至后续系统治疗时间（TFST）、局部控制率（LC）、无进展生存期（PFS）、总生存期（OS）以及放疗相关急性和晚期毒性。结果：从六家意大利和一家瑞士放疗中心共纳入56例患者。治疗总体耐受性良好。10例患者出现1级或2级急性毒性反应，4例患者报告持续性胸痛，其中1例晚期毒性达到3级。中位TFST为18.6个月，12个月和24个月TFST率分别为61.7%和46.4%。中位OS为37.63个月，1年和2年OS率分别为85.2%和65.6%。局部控制情况良好（1年局部控制率79%），但多数患者在SABR治疗范围外出现疾病复发。中位疾病无进展生存期（DPFS）为8.17个月，1年和2年DPFS率分别为36%和19%。单因素分析显示吸烟史与OS和DPFS相关，而多因素分析中OS的统计学显著性仍得以保持。此外，淋巴结状态和计划靶区体积与OS相关。结论：SABR是治疗寡复发/寡进展PM的安全有效方法，可将后续系统治疗时间延长至18个月。两年时10%的患者保持无病状态，超过半数患者在三年时仍存活，提示寡转移性PM可能具有惰性生物学行为特征。
Oligometastatic Mesothelioma Treated with Ablative Radiotherapy (OMAR): A Multicenter Study
肿瘤(癌症)患者之家