9-year experience: Prophylactic cranial irradiation in extensive disease small-cell lung cancer

Abstract Objectives In 2007, the European Organization for Research and Treatment of Cancer (EORTC) study published by Slotman et al. ( ClinicalTrials.gov number, NCT00016211) demonstrated a beneficial impact on overall survival (OS) with the use of prophylactic cranial irradiation (PCI) in extensive disease (ED) small cell lung cancer (SCLC). Nevertheless, there is ongoing debate over the role of PCI as patients in this trial did not undergo magnetic resonance imaging (MRI) of the brain prior to treatment, and a recent Japanese randomized trial presented by Seto et al. showed a detrimental effect of PCI on OS in patients with a negative pre-treatment brain MRI. Methods We examined the medical records of 136 patients with ED SCLC who initially responded to chemotherapy and received PCI between 2007 and 2015. The outcomes, radiation toxicity, neurologic progression-free survival (nPFS), and overall survival (OS) following PCI were analyzed. Survival and correlations were calculated using log-rank and univariate Cox proportional hazards-ratio analyses. Results Median OS after PCI was 12 months and the median nPFS after PCI was 19 months. There was no significant survival difference in patients who received an MRI prior to PCI compared to patients who received a contrast enhanced computer tomography (CT) (p=0.20). Univariate analysis for overall survival did not show a statistically significant effect for known cofactors. Conclusions In this cohort, PCI was associated with improved survival compared to the PCI arm of the EORTC trial, with a nearly doubled median OS time. The median OS was prolonged by two months compared to the irradiation arm of the Japanese trial.