Primary brainstem lymphoma: clinical characteristics, treatment methods, and prognostic factors of 56 patients.

[BACKGROUND] Primary brainstem lymphoma (PBSL) is rare and generally has a poor prognosis. This study aimed to analyze the clinical, therapeutic, and prognostic factors in a single-center retrospective cohort.

[METHODS] Fifty-six patients diagnosed with PBSL from January 2018 to December 2022 were retrospectively enrolled. Data on the clinical course of disease, pathological parameters, neuroradiological imaging, laboratory results, and survival data were collected and analyzed.

[RESULTS] The median age at diagnosis was 56 years (range: 10-77), and 23 (41.1%) patients had a Karnofsky Performance Score ≤60. The mid-brain was the most commonly involved brainstem region (35.7%). The histological type of all patients was diffuse large B-cell lymphoma. The first-line treatment was high-dose methotrexate (HD-MTX)-based chemotherapy, with an overall response rate (ORR) of 70.5%, of which 62.1% achieved complete response. For relapsed or refractory disease, radiotherapy was the most common salvage therapy and significantly improved overall survival (OS). With a median follow-up of 56 months, the median OS for the entire cohort was 30 months (95% CI 18-42 months). In both univariate and multivariate analysis, an age of ≥60 years at diagnosis was a significant prognostic factor for poor OS (hazard ratio [HR] 3.086, P = .003, 95% CI 1.467-6.492) and progression-free survival (HR 2.309, P = .030, 95% CI 1.087-4.905).

[CONCLUSIONS] PBSL has worse survival outcomes compared to tumors in other sites. HD-MTX chemotherapy remains effective, achieving a high ORR. Radiotherapy is an important salvage alternative for rapidly reducing brainstem lesions.