Survival in small cell lung cancer in India: Prognostic utility of clinical features, laboratory parameters and response to treatment

BACKGROUND: Predictors of survival and response to treatment in patients with small cell lung cancer (SCLC) are ill-defined and unclear. In an attempt to assess the impact of common presenting symptoms and laboratory values on survival, we undertook this retrospective review of patients with SCLC. To our knowledge, there is no study on survival in SCLC patients from the Indian subcontinent.
DESIGN: Retrospective Cohort study.
MATERIALS AND METHODS: All newly diagnosed small cell lung cancer cases from December 2001 through December 2004, were identified and clinical data on presenting symptoms and laboratory findings from their hospital records, noted. The influence of various pretreatment factors on survival was investigated using Kaplan-Meier plots and Cox multivariate regression model.
RESULTS: 76 subjects were included (84% males, 91% smokers). 57% patients had five or more symptoms at presentation. Cumulative symptom burden was strongly associated with survival ( P =0.02). Survival was also significantly related with Karnofsky performance status (KPS) ( P =0.04), disease extent (P =0.03) and symptomatic response to treatment ( P< 0.001). Patients with higher hemoglobin ( P =0.02), serum sodium ( P =0.04) and serum globulin ( P =0.02), survived significantly longer. By multivariate regression analysis, hemoglobin, KPS and brain metastases, were significant predictors of survival ( P =0.01, P =0.02, P< 0.01 respectively).
CONCLUSION: Cumulative symptom burden, KPS, disease extent and symptomatic assessment of improvement after treatment, are useful predictors of survival. This has important clinical implications, keeping in view, the infrastructure and cost involved in more objective tests like CT scan, for evaluation of disease extent and prognosis. These findings can provide a simple basis for predicting prognosis in small cell lung cancer, especially in developing countries like ours.

Keywords
Small cell lung cancer, survival, prognostic factors, performance status, symptom burden, symptomatic response to treatment.