There are no widely accepted prognostic indices for extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT). This study aimed to develop and validate a specific prognostic tool to personalize and optimize treatment of patients with MALT lymphoma. A prognostic index was built by Cox regression (stepwise selection) using data from 401 patients enrolled in the international randomized International Extranodal Lymphoma Study Group 19 (IELSG-19) trial (NCT 00210353). A validation set, including 633 patients, was obtained by merging 3 independent cohorts of MALT lymphoma patients. The 3 individual features maintaining the greatest prognostic significance for event-free survival (EFS, the main endpoint of the IELSG-19 trial) were age ≥70 years (hazard ratio [HR], 1.72; 95% confidence interval [CI], 1.26-2.33), Ann Arbor stage III or IV (HR, 1.79; 95% CI ,1.35-2.38), and an elevated lactate dehydrogenase level (HR, 1.87; 95% CI, 1.27-2.77). The prognostic index (MALT-IPI) constructed using these 3 parameters identified 3 groups: low, intermediate, and high risk (corresponding to the presence of 0, 1, or ≥2 of these factors, respectively). The 5-year EFS rates in the low-, intermediate-, and high-risk groups were 70%, 56%, and 29%, respectively. The MALT-lymphoma International Prognostic Index (MALT-IPI) also significantly discriminated between patients with different progression-free, overall, and cause-specific survival. The prognostic utility was retained in gastric and nongastric lymphomas, in each treatment arm (chlorambucil, rituximab, and rituximab plus chlorambucil), and was confirmed in the validation set. The new index, MALT-IPI, is a simple, accessible, and effective tool to identify MALT lymphoma patients at risk of poor outcomes. It may help define appropriate treatment approaches for individual patients.

粘膜相关淋巴样组织（MALT）的结外边缘区淋巴瘤尚无广泛接受的预后指标。这项研究旨在开发和验证一种特定的预后工具，以个性化和优化MALT淋巴瘤患者的治疗。通过Cox回归（逐步选择），使用来自国际19次国际随机结外淋巴瘤研究组（IELSG-19）试验（NCT 00210353）的401名患者的数据，建立了预后指标。通过合并3个独立的MALT淋巴瘤患者队列，获得包括633名患者的验证集。维持无事件生存的最大预后意义的3个个体特征（EFS，IELSG-19试验的主要终点）是年龄≥70岁（危险比[HR]，1.72； 95％置信区间[CI]，1.26） -2.33），Ann Arbor III或IV期（HR，1.79； 95％CI，1.35-2.38），乳酸脱氢酶水平升高（HR，1.87； 95％CI，1.27-2.77）。使用这3个参数构建的预后指数（MALT-IPI）确定了3组：低，中和高风险（分别对应于这些因素的存在0、1或≥2）。低，中和高风险组的5年EFS率分别为70％，56％和29％。MALT-淋巴瘤国际预后指数（MALT-IPI）也可以明显区分具有不同无进展生存期，总体生存期和特定病因生存期的患者。在每个治疗组（苯丁酸氮芥，利妥昔单抗和利妥昔单抗加苯丁酸氮芥）的胃和非胃淋巴瘤中均保留了预后效用，并在验证集中进行了确认。新索引MALT-IPI很简单，一种易于使用且有效的工具，以识别具有不良结果风险的MALT淋巴瘤患者。它可能有助于为个别患者定义适当的治疗方法。