Clinical characteristics and prognosis analysis of secondary intestinal diffuse large B-cell lymphoma: a multi-center retrospective study over a decade

Background and objective Secondary intestinal diffuse large B-cell lymphoma (SI-DLBCL) is a clinically rare hematological malignancy characterized by high invasiveness and heterogeneity. Due to its nonspecific clinical manifestations, it is often misdiagnosed or overlooked in clinical practice, leading to poor patient outcomes. This study aims to systematically explore and analyze the clinical characteristics and prognostic factors of SI-DLBCL, providing valuable insights for basic research and clinical management of secondary lymphomas at rare sites within the field of Hematology. Methods This multicenter retrospective study enrolled 483 patients diagnosed with SI-DLBCL between January 1, 2015, and December 31, 2025, spanning an 11-year period; clinical data were retrospectively collected from five tertiary medical centers across different regions of China: Fujian Medical University Union Hospital, Affiliated Hospital of Putian University, the First Affiliated Hospital of Gannan Medical University, Affiliated Hospital of Guangdong Medical University and the Affiliated Ganzhou Hospital of Nanchang University. The data included clinical and pathological features, treatment regimens, and prognosis. Univariate and multivariate Cox regression analyses were conducted to identify significant prognostic factors. Results Among the 483 patients with SI-DLBCL, 298 cases were male (61.70%) and 185 cases were female (38.30%), with a median age of onset of 60.5 years (range: 18–84 years). Clinical manifestations were predominantly nonspecific, and the first-line treatment primarily consisted of chemotherapy. The median follow-up duration was 70 months (range: 0.5–135 months). Specifically, 322 cases (66.67%) received chemotherapy alone, 146 cases (30.23%) received a combination of chemotherapy and surgical intervention, and 15 cases (3.10%) underwent surgery alone. The overall response rate (ORR), defined as the sum of CR and PR, shows significant differences between the three groups for patients with SI-DLBCL ( P = 0.002). Age, Lugano stage, IPI score, serum LDH, albumin (ALB), β2 microglobulin, first-line treatment showed statistically significant differences between the survival group and the death group ( P < 0.05). Univariate Cox regression analysis identified age, Lugano stage, IPI score, LDH, ALB, β2-microglobulin, and first-line treatment as significant predictors of OS and PFS. Multivariate analysis confirmed that age and Lugano stage were independent prognostic factors affecting both OS and PFS. The results of univariate logistic analysis showed that age, Lugano stage, IPI score, serum LDH, ALB, β2 microglobulin, first-line treatment were risk factors for mortality in SI-DLBCL patients (all P < 0.05). Multivariate logistic regression analysis confirmed that advanced age and advanced Lugano stage served as independent risk factors for all-cause mortality. In contrast, patients aged ≤60 years, with Lugano stage I–II disease, IPI scores of 0–2, normal serum LDH levels, serum albumin ≥35 g/L, β2-microglobulin ≤3 μg/ml, and those receiving combined chemotherapy plus surgical resection exhibited significantly more favorable long-term prognosis in univariate analysis. Conclusion SI-DLBCL predominantly affects middle-aged and elderly men, with nonspecific early clinical manifestations. Chemotherapy, particularly the R-CHOP regimen, remains the primary treatment modality. For patients with localized intestinal lesions or acute intestinal complications (perforation, massive bleeding, or obstruction), surgical intervention combined with rituximab-based systemic chemotherapy may be considered as a multidisciplinary treatment strategy; however, due to the retrospective study design and confounding by indication, this observation should be further validated in prospective studies. Age and Lugano stage are independent prognostic factors influencing OS and PFS in patients with SI-DLBCL.