BACKGROUND: Primary lymphoma of the breast is rare, and primary diffuse large B cell lymphoma (DLBCL) of the breast is very rare. This study aimed to identify the clinicopathological characteristics and treatment associated with prognosis in patients with primary DLBCL of the breast.

MATERIAL AND METHODS: A retrospective study included the clinical and treatment data from 46 women with a histological diagnosis of primary DLBCL. Patients were staged using Ann Arbor staging criteria, overall survival (OS), progression-free survival (PFS), and the international prognostic index (IPI) scores were obtained. Laboratory finding included serum lactate dehydrogenase (LDH), and the immunohistochemistry findings were recorded.

RESULTS: Patients (n=46), included stage I (n=18), stage II (n=18), stage III (n=3), and stage IV DLBCL (n=9). Treatment included chemotherapy with rituximab (n=16), and radiotherapy (n=12). The median follow-up time was 40.5 months, the 5-year OS rate was 36.2%, and the 5-year PFS rate was 29.1%. Univariate analysis showed that clinical stage, serum LDH, the IPI score, chemotherapy cycles >3, and Bcl-2 and Bcl-6 expression were correlated with the 5-year OS and PFS. Multivariate risk regression analysis showed that the number of chemotherapy cycles (>3) and Bcl-6 expression were independent prognostic factors in primary DLBCL of the breast (P<0.05).

CONCLUSIONS: A retrospective study of 46 patients with primary DLBCL of the breast showed that >3 cycles of chemotherapy and expression of Bcl-6 resulted in improved OS and PFS. Radiotherapy controlled local tumor recurrence but did not improve the OS and PFS. Rituximab did not improve patient survival.

Keywords: Breast, Lymphoma, Large B-Cell, Diffuse, Disease-Free Survival, Immunohistochemistry, Multivariate Analysis, Progression-Free Survival, rituximab, Survival Rate