While the effect of chemotherapy dose on tumor response in small cell lung cancer has been fairly well established, the effect on survival has been retrospectively analyzed only in some series. This particular point was studied in a series of 52 consecutive patients with limited small cell lung cancer treated by an alternating radiotherapy-chemotherapy schedule. The induction treatment consisted of 6 chemotherapy cycles (the planned doses were: doxorubicin 40 mg/m2 day 1, VP16213 75 mg/m2 days 1-3, cyclophosphamide 300 mg/m2 days 3-6, and cisplatinum 100 mg/m2 day 2) alternated after the first 2 cycles with 3 courses of thoracic radiotherapy delivering a total dose of 55 Gy. Eighty-one percent of patients went into complete remission and the 3-year relapse-free survival was 24%. A multivariate analysis of prognostic factors took into account age, sex, T stage, performance status, delayed hematological toxicity to the first course of chemotherapy, actual dose/m2 of each drug during the first course and mean dose/course delivered during the induction treatment after the first cycle of chemotherapy. It was possible to identify 3 independent factors influencing overall survival and relapse-free survival: actual initial dose of cisplatinum, actual initial dose of cyclophosphamide and the T stage. The effect of the initial dose of cisplatinum and cyclophosphamide proved to be linear on relapse-free survival. The results of this analysis show a possible effect of initial doses of chemotherapy in the management of limited small cell lung cancer in terms of both distant metastasis and overall survival rates.