The management of small cell lung cancer (SCLC) has reached a plateau. Etoposide and platinum-based chemotherapy plus thoracic irradiation remain the standard treatment strategy for SCLC. Our study aims to assess the potential prognostic factors of patients treated with etoposide and platinum-based chemotherapy and explore which group of patients can benefit more from standard treatment strategies. On univariate analysis, age>65 years, male patients, KPS (Karnofsky Performance Status)≤80 points, positive smoking history, anemia, lymphocyte counts≤1.65×109/L, neutrophil to lymphocyte ratio (NLR)>3.18, lymphocyte to monocyte ratio (LMR)≤2.615, lactate dehydrogenase (LDH)>216.5 U/L, alkaline phosphatase (ALP)>119.5 U/L, absence of surgery, absence of thoracic irradiation, chemotherapy cycles<4, metastatic sites≥2 and extensive disease were correlated with a poor prognosis. Gender, KPS, chemotherapy cycles, thoracic irradiation, metastatic sites, LDH and tumor stage held statistical significance on multivariate analysis (p<0.05). High LDH was closely correlated with extensive disease, metastatic sites≥2, anemia, low LMR, high NLR and ALP levels. Subgroup analysis showed patients with male gender, KPS≤80 points, LDH≤216.5U/L, extensive disease and metastatic sites<2 could benefit more from ≥4 chemotherapy cycles. Patients with male gender, KPS>80 points, LDH≤216.5U/L, limited disease and metastatic sites<2 could benefit more from thoracic irradiation (p<0.05 on uni- and multivariate analysis). In conclusion, female patients, KPS>80 points, chemotherapy cycles≥4, thoracic irradiation, metastatic sites<2, LDH≤216.5U/L and limited disease were independent positive prognostic factors for SCLC patients treated with etoposide and platinum-based chemotherapy. Selected patients can benefit more from the management of ≥4 cycles of chemotherapy and thoracic irradiation.
Keywords: inflammation; prognostic factors; small cell lung cancer; subgroup analysis; survival.