(ChemotherapyAdvisor) – Prophylactic cranial irradiation (PCI) decreased the 5-year rate of brain metastases in patients with locally advanced non- small cell lung cancer (NSCLC) but not overall survival (OS)—the primary end point—or disease-free survival (DFS), an updated 5-year analysis presented at the 2012 Chicago Multidisciplinary Symposium in Thoracic Oncology confirmed.

The Radiation Therapy Oncology Group 0214 study, initiated September 2002, had a target accrual of 1,058 participants; however, due to slow accrual, the study was closed after 356 patients were enrolled. These results focused on 340 patients evaluable for analysis, noted Elizabeth Gore, MD, lead study author and Professor of Radiation Oncology at the Medical College of Wisconsin, Milwaukee, WI.

Patients with stage III NSCLC without disease progression after treatment with surgery and/or radiation therapy with or without chemotherapy were randomly assigned to PCI (delivered to 30Gy in 15 fractions) or observation. Patients were stratified by stage, histology, and therapy.

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Median follow-up time was 24.2 months for all patients; 58.6 months for living patients. At 5 years, OS was 26.1% for the PCI arm vs 24.6% for the observation arm (P=0.57); 5-year DFS was 18.5% vs 14.9% (P=0.13), respectively. Patients in the PCI arm had a significantly decreased rate of brain metastases at 5-years, 17.3%, compared with 26.8% for the observation arm (P=0.009).

“Of the patients who failed, 10% of patients on the PCI arm and 23% of patients on the observation arm experienced failure in the brain initially,” Dr. Gore stated. “Brain metastases were the only component of first failure in 9.1% and 21.5% of patients with and without PCI.”

PCI was significantly associated with decreased brain metastases on multivariate analysis. While nonsquamous histology was associated with an increased risk, the rate of brain metastases overall was insufficient for reliable subset analyses by histology.

“Further information is needed to determine which patient subset could derive a survival benefit from PCI,” Dr. Gore concluded.

The symposium is sponsored by the American Society of Clinical Oncology, the American Society for Radiation Oncology, the International Association for the Study of Lung Cancer, and the University of Chicago.