Clinicopathological Characteristics and Survival Outcomes of Male Breast Lymphoma

Background: Male breast lymphoma is rare, and most evidence on prognosis and treatment comes from female-predominant or mixed cohorts. We evaluated clinicopathological characteristics and cancer-specific survival (CSS) in men with lymphoma recorded as the primary breast site in SEER. Methods: Male patients diagnosed between 2000 and 2021 with lymphoma recorded as the primary breast site in SEER were identified. CSS was estimated using Kaplan-Meier methods and compared with the log-rank test. Cox proportional hazards models were used to explore factors associated with CSS. Results: A total of 138 male patients were included. Most patients were aged ≥65 years (62.3%). Diffuse large B-cell lymphoma was the most common histological subtype (39.1%), followed by mucosa-associated lymphoid tissue (MALT) lymphoma (23.9%) and follicular lymphoma (17.4%). Among patients with known Ann Arbor stage, stage I disease was the most frequent presentation (48.8%). Chemotherapy was recorded in 44.9% of patients and radiotherapy in 31.2%. In univariable analysis, age (p < 0.001), histological subtype (p < 0.001), stage (p = 0.040), radiotherapy (p = 0.038), and chemotherapy (p = 0.020) were associated with CSS. Primary breast surgery was not associated with CSS (p = 0.556). Conclusions: In this SEER-based study of 138 men with breast lymphoma, older age and aggressive histology were independently associated with poorer CSS. Stage and treatment variables showed associations mainly in univariable analysis. These findings should be interpreted cautiously because of missing data, treatment-selection bias, and the lack of detailed treatment information in SEER. This study provides one of the largest and most updated male-only SEER analyses of this rare disease. Larger collaborative datasets with clinical, pathological, molecular, and treatment details are needed to better define prognosis and support individualized treatment.