Whether gastric mucosa-associated lymphoid tissue lymphoma (GML) is associated with a higher risk of second primary malignancy (SPM) remains controversial. This study aimed to evaluate the detailed risk of SPM and its prognosis in patients with GML based on a large population-based cohort. The Surveillance, Epidemiology, and End Results database was searched to identify patients who were diagnosed with GML during 2000–2014. The standardized incidence ratio was used to estimate the relative risk of developing SPM. Overall survival was evaluated using the Kaplan-Meier method with the log-rank test, as well as Cox regression analysis. Among 3,379 patients with GML, 416 patients (12.31%) developed SPMs. Compared to the general US population, GML patients had a significantly increased risk of developing SPM (standardized incidence ratio: 1.46, 95% CI: 1.33–1.61). The SPM sites were stomach, lung and bronchus, small intestine, thyroid, mouth, and non-Hodgkin's lymphoma. The risk of developing SPM in GML patients varied according to clinical and demographic characteristics. Patients with younger age (<50 year), chemotherapy use and radiotherapy use had the higher risk of developing SPMs. Relative to patients with only GML, GML patients who developed the SPMs had significantly poorer overall survival (P < 0.001). Among GML patients with SPMs, poor overall survival was independently associated with non-localized SPM disease, shorter latency period (<60 months), chemotherapy use and older age (≥70 year). Patients with GML had an elevated risk of developing SPM, which was associated with a poor prognosis. These findings may be useful for improving follow-up surveillance for patients with GML.

胃黏膜相关淋巴组织淋巴瘤（GML）是否与第二原发性恶性肿瘤（SPM）的高风险相关仍然存在争议。本研究旨在基于大型人群队列评估 GML 患者 SPM 的详细风险及其预后。搜索了监测、流行病学和最终结果数据库，以确定 2000 年至 2014 年期间被诊断为 GML 的患者。标准化发病率用于估计发生 SPM 的相对风险。使用 Kaplan-Meier 方法和对数秩检验以及 Cox 回归分析评估总生存期。在 3,379 名 GML 患者中，416 名患者 (12.31%) 发生了 SPM。与美国一般人群相比，GML 患者发生 SPM 的风险显着增加（标准化发病率：1.46，95% CI：1.33-1.61)。SPM 部位是胃、肺和支气管、小肠、甲状腺、口腔和非霍奇金淋巴瘤。GML 患者发生 SPM 的风险因临床和人口统计学特征而异。年龄较小（<50 岁）、使用化疗和放疗的患者发生 SPM 的风险较高。相对于仅患有 GML 的患者，发生 SPM 的 GML 患者的总生存期明显较差（P < 0.001）。在患有 SPM 的 GML 患者中，较差的总生存期与非局限性 SPM 疾病、较短的潜伏期（<60 个月）、化疗使用和年龄较大（≥70 岁）独立相关。GML 患者发生 SPM 的风险升高，这与预后不良有关。