Supplementary Material for: Prognostic Factors in Pleural Mesothelioma Patients Receiving First-Line Chemotherapy: Establishing the PLECH Baseline Risk Score

Introduction: Pleural Mesothelioma (PM) is a rare and aggressive cancer where prognostic assessment is crucial. Traditional prognostic scores such as the European Organisation for Research and Treatment of Cancer (EORTC) and the Cancer and Leukaemia Group B (CALGB) have limitations, particularly in reflecting contemporary treatments and demographic diversities, while more recent scores often include novel biomarkers, not widely available and validated. Our goal is to create an effective prognostic score for PM using readily available baseline data. Methods: A retrospective cohort study at two Mexican cancer centers included patients with unresectable PM treated with first-line chemotherapy from 2010 to 2023. Baseline variables' associations with overall survival (OS) and progression-free survival (PFS) were analyzed. Prognostic variables from univariate and multivariate analyses formed a baseline risk score. The score's OS prediction was compared to standard CALGB and EORTC scores using ROC curves and Kaplan-Meier analysis. Results: Among 262 patients (69.1% male, 80.5% epithelioid histology), we developed a 0-7 point PLECH score based on five variables: Platelet count (P: +2), high LDH (L: +1), ECOG ≥ 2 (E: +1), Chest pain at diagnosis (C: +2), and non-epithelioid Histology (H: +1). The score had an AUC of 0.70 for predicting 1-year OS, outperforming CALGB (0.60) and EORTC (0.57) scores, with an optimal cut-off of 2.5 (sensitivity 75%, specificity 55%). High scores (≥3) indicated worse OS (12.3 vs. 20.1 months; p<0.001) and PFS (6.4 vs. 11.3 months; p<0.001). Conclusion: The PLECH score, developed from a substantial Latin-American cohort, is a simple and effective prognostic tool for PM patients, outperforming traditional scores. It identifies a high-risk group potentially better suited to alternative treatments.引言：胸膜间皮瘤（Pleural Mesothelioma, PM）是一种罕见且侵袭性极强的癌症，预后评估对其临床管理至关重要。传统预后评分系统如欧洲癌症研究与治疗组织（European Organisation for Research and Treatment of Cancer, EORTC）评分、癌症与白血病研究组B（Cancer and Leukaemia Group B, CALGB）评分均存在一定局限性，尤其难以反映当代治疗方案与人群人口学特征的多样性；而近年新兴的预后评分多纳入新型生物标志物，但此类标志物尚未得到广泛应用与验证。本研究旨在基于易于获取的基线数据，构建一款实用有效的胸膜间皮瘤预后评分模型。方法：本研究为回顾性队列研究，纳入2010年至2023年间在墨西哥两家癌症中心接受一线化疗治疗的不可切除胸膜间皮瘤患者。分析基线变量与总生存期（Overall Survival, OS）、无进展生存期（Progression-Free Survival, PFS）的相关性。通过单因素与多因素分析筛选预后变量，构建基线风险评分模型。采用受试者工作特征曲线（ROC曲线）与Kaplan-Meier分析，将该评分对总生存期的预测效能与标准CALGB、EORTC评分进行对比。结果：本研究共纳入262例患者，其中男性占比69.1%，上皮样组织学类型占比80.5%。基于5项变量构建了0至7分的PLECH评分：血小板计数（P项：+2分）、乳酸脱氢酶水平升高（L项：+1分）、美国东部肿瘤协作组（ECOG）体能状态评分≥2分（E项：+1分）、确诊时存在胸痛（C项：+2分）以及非上皮样组织学类型（H项：+1分）。该评分预测1年总生存期的曲线下面积（AUC）为0.70，优于CALGB评分（0.60）与EORTC评分（0.57），最佳截断值为2.5，此时灵敏度为75%、特异度为55%。评分≥3分的高危组患者总生存期更差（中位总生存期12.3个月 vs 20.1个月；p<0.001），无进展生存期亦显著缩短（中位无进展生存期6.4个月 vs 11.3个月；p<0.001）。结论：基于大规模拉丁美洲人群队列构建的PLECH评分，是一款简便高效的胸膜间皮瘤患者预后评估工具，其预测效能优于传统预后评分系统。该评分可精准识别高危患者群体，这类患者或更适合采用替代治疗方案。