Radiotherapy for patients with brain metastases and leptomeningeal carcinomatosis: prognostic factors and clinical outcomes.

Brain metastases and leptomeningeal carcinomatosis (LC) are complications of advanced-stage malignancies, associated with a poor prognosis. This study aimed to evaluate the role of prognostic factors and radiotherapy (RT) treatment approaches while taking toxicity into account. We performed a retrospective study and compared clinical characteristics, prognostic factors, toxicities and outcomes in patients with (1) parenchymal brain metastases (PM) (n = 275) vs. LC (n = 35) and (2) in patients with whole brain radiotherapy (WBRT) (n = 52) vs. WBRT + boost (n = 201). We found poorer survival (OS) of the LC group compared to PM patients in univariable analysis (not in multivariable analysis). LC patients predominantly underwent WBRT only, received surgical resection before RT less frequently and had more RT discontinuations than PM patients. OS was better in the WBRT + boost group than in the WBRT only group. In patients who received WBRT + boost, the primary tumor was more often controlled, and the number of PM was lower compared to the WBRT only group. WBRT + boost was associated with higher rates of alopecia than WBRT only. Patients with LC had a worse prognosis compared to patients with PM. WBRT + boost resulted in higher toxicity than WBRT only but resulted in better OS in the presented study. WBRT + boost patients had more favorable prognostic factors prior to RT, so OS improvement is not likely due to boost. Treating brain metastases requires a careful assessment of benefits and risks. Optimal RT planning should consider prognostic factors and potential side effects individually.