Time From Treatment to Subsequent Diagnosis of Brain Metastases in Stage III Non–Small-Cell Lung Cancer: A Retrospective Review by the Southwest Oncology Group

Abstract

Purpose A retrospective review of the Southwest Oncology Group (SWOG) database was undertaken to review the incidence and timing of diagnosis of brain metastases in patients undergoing combined-modality therapy for stage III non–small-cell lung cancer (NSCLC). Patients and Methods Four hundred twenty-two eligible, assessable patients with stage IIIA/B NSCLC were treated on four SWOG protocols. Treatment varied with protocol but consisted of concurrent cisplatin-etoposide and radiation in all patients, with a surgery arm in two of the four protocols. Results Of the 422 total patients, 268 (64%) have experienced disease progression; 54 relapses (20%) were in brain only, 17 (6.5%) were in brain and other sites simultaneously, and 197 (63.5%) were in sites other than brain. Of the 268 patients with disease progression, progression in the brain only, in the brain and other sites, and not in the brain occurred in 20%, 6%, and 74% of patients, respectively. Time from treatment to diagnosis of disease progression in the brain in 71 patients was as follows: during treatment, 16 relapses (22.5%); 0 to 16 weeks after treatment, 17 relapses (24%); 16 weeks to 6 months after treatment, 10 relapses (14%); 6 to 12 months after treatment, 16 relapses (22.5%); and more than 12 months after treatment, 12 relapses (17%). Nonsquamous histology and young patient age were the only significant predictors for increased risk of early relapse with brain metastases. Conclusion Brain metastases often develop early in the course of treatment for stage IIIA/B NSCLC. The statistical designs of ongoing trials of prophylactic cranial irradiation in stage III NSCLC have taken this into account.