Chemotherapy versus chemotherapy plus irradiation in limited small cell lung cancer. Results of a controlled trial with 5 years follow-up

Abstract

One hundred and forty-five patients with limited stage small cell lung cancer were included in a randomized trial to evaluate the effect of chemotherapy with or without chest irradiation. Seventy-six patients were allotted chemotherapy alone while 69 patients received the same chemotherapy plus radiotherapy, 40 Gy in split-course, administered in weeks 6 and 10 after the initiation of chemotherapy. The chemotherapy consisted of lomustine, cyclophosphamide, vincristine and methotrexate. Patients treated with chemotherapy alone survived for a median of 52 weeks compared to 44 weeks in patients receiving the combined regimen (P = 0.055). After exclusion of five early deaths and one patient refusing the irradiation plus 14 completely resected patients, the remaining 65 patients receiving chemotherapy alone and the 60 patients treated with chemotherapy plus radiotherapy were included in a new analysis. The difference in survival duration which could be ascribed to treatment with or without chest irradiation thereby diminished (P = 0.24). Eighteen months' disease-free survival was obtained in 9.2% of the 65 patients and in 9.8% of the 60 patients. The complete remission rates were 37% and 46%, respectively, (P = 0.33) and the median durations of complete remission were 40 weeks and 52 weeks (P = 0.67). Treatment failure of the primary tumour occurred in 85% of patients treated with chemotherapy alone in contrast to 61% of patients receiving the combined regimen (P = 0.005). Seventy-nine of these patients underwent autopsy at which no residual chest disease was observed in 17% and 37%, respectively (P = 0.045). The combined regimen was more toxic than chemotherapy alone resulting in significantly greater dose reductions and more pronounced thrombocytopenia. Lung and pericardial fibrosis was responsible for four deaths among the complete responders in the radiotherapy group. The combined regimen thus tended to be more efficacious with respect to tumour control at the expense, however, of increased toxicity which per se, eliminated a potential improvement of the overall therapeutical results.