Role of Adjuvant Therapy in a Population-Based Cohort of Patients With Early-Stage Small-Cell Lung Cancer.

PURPOSE: Data on optimal adjuvant therapy after complete resection of small-cell lung cancer (SCLC) are limited, and in particular, there have been no studies evaluating the role of adjuvant chemotherapy, with or without prophylactic cranial irradiation, relative to no adjuvant therapy for stage T1-2N0M0 SCLC. This National Cancer Data Base analysis was performed to determine the potential benefits of adjuvant chemotherapy with and without prophylactic cranial irradiation in patients who undergo complete resection for early-stage small-cell lung cancer. PATIENTS AND METHODS: Overall survival of patients with pathologic T1-2N0M0 SCLC who underwent complete resection in the National Cancer Data Base from 2003 to 2011, stratified by adjuvant therapy regimen, was evaluated using Kaplan-Meier and Cox proportional hazards analysis. Patients treated with induction therapy and those who died within 30 days of surgery were excluded from analysis. RESULTS: Of 1,574 patients who had pT1-2N0M0 SCLC during the study period, 954 patients (61%) underwent complete R0 resection with a 5-year survival of 47%. Adjuvant therapy was administered to 59% of patients (n = 566), including chemotherapy alone (n = 354), chemoradiation (n = 190, including 99 patients who underwent cranial irradiation), and radiation alone (n = 22). Compared with surgery alone, adjuvant chemotherapy with or without radiation was associated with significantly improved survival. In addition, multivariable Cox modeling demonstrated that treatment with adjuvant chemotherapy (hazard ratio [HR], 0.78; 95% CI, 0.63 to 0.95) or chemotherapy with radiation directed at the brain (HR, 0.52; 95% CI, 0.36 to 0.75) was associated with improved survival when compared with no adjuvant therapy. CONCLUSION: Patients with pT1-2N0M0 SCLC treated with surgical resection alone have worse outcomes than those who undergo resection with adjuvant chemotherapy alone or chemotherapy with cranial irradiation.