Smoking and effect of chemotherapy in small cell lung cancer.

The relationship between smoking habits and outcome of treatment was studied in 154 patients with small cell lung cancer (SCLC) who received combination chemotherapy. Thirty-two patients had stopped smoking at least 6 months before the initiation of treatment or had never smoked (NS), 51 patients stopped smoking less than 6 months prior to the start of treatment (SS) and 71 patients continued to smoke during the treatment period (CS). Life table analysis of overall survival showed no significant heterogeneity among the groups (p greater than 0.7). Chi-square test for trend in survival yielded 0.23 (p greater than 0.6) with the longest survival in SS and CS patients, and the shortest survival in NS patients. Corresponding analysis of time to progression showed similar results, with a non-significant heterogeneity (p greater than 0.5) and trend (p greater than 0.4) among the three groups, with the CS patients doing best. In the whole series the disease-free two-year survival rate was higher in the CS patients than in the SS and NS patients (p = 0.04). The results do not imply that continued smoking during chemotherapy in SCLC has unfavourable effects on the outcome of treatment.