Retrospective analysis of outcomes and prognostic factors of chemotherapy for small-cell lung cancer

BACKGROUND Small-cell lung cancer (SCLC) is responsive to initial chemotherapy but becomes resistant to cytotoxic drugs. The aim of this study was to evaluate what proportion of patients with SCLC had received the first- and further-line chemotherapy and which patients had benefited from chemotherapy. METHODS We retrospectively reviewed medical records of patients with SCLC who had been treated with the best supportive care alone and the first-, second-, or third-line chemotherapy at the Osaka Police Hospital from June 2007 until March 2015. RESULTS Among 145 patients diagnosed with SCLC and eligible for analysis, 118 patients received chemotherapy. We added five patients who initiated the second-line chemotherapy during the study period at our institution. Sixty-five and 31 patients received the second- and third-line chemotherapies, respectively. Multivariate logistic regression analysis detected age ≥75 years (odds ratio, 2.80; 95% confidence interval, 1.01-7.75; P=0.047) and European Clinical Oncology Group Performance Status (ECOG PS) 3-4 (14.3; 4.86-41.9; P<0.01) as factors disturbing the introduction of chemotherapy. Multivariate Cox hazard analyses also detected ECOG PS 2-4 (3.34; 2.00-5.58; P<0.01) as a factor decreasing overall survival after the first-line chemotherapy, and C-reactive protein level ≥1.0 mg/dL (2.67; 1.30-5.47; P<0.01) and progression-free survival after the first-line chemotherapy ≥6 months (2.85; 1.50-5.43; P<0.01) as factors influencing overall survival after the second-line chemotherapy. CONCLUSION Approximately two-thirds and one-third of the patients who receive chemotherapy proceed to the second- and third-line chemotherapies, respectively. Several factors, such as age, ECOG PS, C-reactive protein level, and progression-free survival after previous treatment may be useful when considering the introduction of further-line chemotherapy.