Consolidation reduced-dose whole-brain radiation therapy with response-adapted boost in older patients with newly...

Primary central nervous system lymphoma (PCNSL) is relatively common among elderly patients, for whom survival outcomes remain limited and treatment-related decline in functional status is a major concern. This study evaluated the efficacy and functional preservation of reduced-dose whole-brain radiotherapy (WBRT) followed by a response-adapted focal boost as consolidation therapy for PCNSL, with a focus on elderly patients.

We retrospectively reviewed patients with PCNSL who received consolidation WBRT at a dose of 23.4 Gy after remission-induction therapy with methotrexate, procarbazine, and vincristine at Miyagi Cancer Center between 2015 and 2022. Patients who did not achieve a complete response (CR) after induction therapy received an additional focal boost of 21.6 Gy. Consolidation high-dose cytarabine was generally administered irrespective of response. Median progression-free survival (PFS), median overall survival (OS), and the duration of preserved Karnofsky Performance Status (KPS) scores ≥ 70 were assessed.

Seventy-three patients were included, with a median age of 69 years. The median PFS and OS were 63 months and 90 months, respectively. Multivariate analyses showed that neither advanced age nor an Eastern Cooperative Oncology Group Performance Status (ECOG PS) score ≥ 2 significantly affected PFS or OS. At 4 years, the proportions of patients maintaining KPS scores ≥ 70 were 100%, 92%, and 80% in patients aged < 60, 60-69, and ≥ 70 years, respectively.

Reduced-dose WBRT (23.4 Gy) combined with a response-adapted focal boost was associated with favorable survival and sustained functional preservation, even in elderly or low-PS patients. This strategy may be an effective and feasible consolidation option for frail older patients with PCNSL.