Evaluation of gefitinib efficacy according to body surface area in patients with non-small cell lung cancer harboring an EGFR mutation

Exon 19 deletions and L858R point mutation are the most commonly encountered active epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC), and they predict greater efficacy of gefitinib therapy. The objective of this study was to evaluate whether body surface area (BSA) affects the efficacy of gefitinib in patients with NSCLC harboring an active EGFR mutation. We reviewed the medical records of consecutive patients with advanced NSCLC harboring an active EGFR mutation who received gefitinib monotherapy. The median BSA value was used as the cutoff value to evaluate the impact of BSA on the efficacy of gefitinib. The median BSA of the 103 NSCLC patients harboring an active EGFR mutation was 1.45 m(2). The overall response rate, progression-free survival (PFS), and median survival time (MST) were 65.0 %, 11.3 months, and 26.2 months, respectively. There were no significant differences in clinical outcomes between the high-BSA group (BSA a parts per thousand yen 1.45 m(2)) and low-BSA group (BSA < 1.45 m(2)), i.e., the response rates was 60.0 % and 69.8 %, respectively (P = 0.20), and their MST was 24.7 and 26.2 months, respectively (P = 0.78). Although BSA was predictive of PFS between high-BSA group and low-BSA group in the univariate analysis (9.0 and 12.2 months, P = 0.04), the multivariate analysis identified only performance status and smoking status as independent predictors of PFS. The efficacy of gefitinib in patients with NSCLC harboring an EGFR mutation does not differ according to their BSA.