[Postoperative radiotherapy in non-small cell lung cancer. Apropos of a series of 374 cases]

Abstract

Purpose: Several randomized trials have led us to address the usefulness of post-surgical external beam therapy (EBT) in non-oat cell bronchial carcinoma. Results that were obtained in a group of 374 patients submitted between 1977 and 1994 to identical therapy-the follow-up being done by the same team-and results of six randomized trials are analyzed.

Patients and methods: The tumor stages were the following: T1, 13%; T2, 56%; T3, 29%; and T4, 2%; N0, 31%; N1, 34%; and N2, 35%. There were 85% histologically complete resections. EBT was administered according to either the classical irradiation scheme (C) or as an 'equivalent hypofractionated dose' (H) in the case of complete resection. When resection was not complete, 60 to 65 Gy were administered according to a C or an H irradiation scheme. The irradiation scheme was C in 73% of the cases and H in 27%. The EBT technique has been chosen to ensure maximum lung sparing. Following a 45 Gy-irradiation with anteroposterior beams, orthogonal or, when necessary, oblique beams were used. Non homogeneity of the lungs was taken into account in establishing the treatment planning. The treatment file was collectively checked by the medical staff in 75% of the cases. EBT was indicated for N+(N1+N2), T3 and incomplete resections.

Results: The overall survival was 42% at 5 years and 27% at 10 years. The 5-year survival was 52% for stage I cancer (T1N0-T2N0), 60% for stage II cancer (T1N1-T2N1), 31% for stage IIIa cancer (T3N0, T1-3N2), 45% for complete resection and 30% when resection was not complete.

Conclusion: Regarding the benefits of post-surgical radiotherapy, the analysis of the six randomized trials does not allow any conclusion. This might be due to either the insufficient number of cases, a follow-up time not long enough, incorrect radiotherapy, or insufficient available data. Comparison of the results pertaining to the six trials with those of our series shows an advantage for the current series, indicating that survival is likely to be improved if EBT is correctly done with regard to the dose, volume and technique used.