Abstract
PURPOSE: To investigate the effect of socioeconomic status, as measured by education, on the survival of 1,577 lung cancer patients treated on 11 studies conducted by the Cancer and Leukemia Group B. PATIENTS AND METHODS: Sociodemographic data, including education, was reported by the patient at the time of clinical trial accrual. Cox proportional hazards model stratified by treatment arm/study was used to examine the effect of education on survival after adjustment for known prognostic factors. RESULTS: The patient population included 1,177 patients diagnosed with non-small-cell lung cancer (NSCLC; stage III or IV) and 400 patients diagnosed with small-cell lung cancer (SCLC; extensive or limited). Patients with less than an eighth grade education (13% of patients) were significantly more likely to be male, nonwhite, and older; have a performance status (PS) of 1 or 2; and have chest pain. Significant predictors of poor survival in the final model included male sex, PS of 1 or 2, dyspnea, weight loss, liver or bone metastases, unmarried, presence of adrenal metastases and high alkaline phosphatase levels among patients with NSCLC, and high WBC levels among patients with advanced disease. Education was not predictive of survival. CONCLUSION: The physical condition of patients with low education who enroll onto clinical trials is worse than patients with higher education. Once enrolled onto a clinical trial, education does not affect the survival of patients with SCLC or stage III or IV NSCLC. The standardization of treatment and follow-up within a clinical trial, regardless of education, is one possible explanation for this lack of effect.