Localized small-cell lung cancer: which type of thoracic radiotherapy and which time schedule

Abstract

The effect of scheduling combined radio-chemotherapy was studied in randomised trials for limited-disease small-cell lung cancer. The available trials with constant overall treatment time of combination therapy were separated into three classes: (1) same radiotherapy scheme, given early vs. late, (2) split-course radiotherapy, given alternately with chemotherapy, vs. continuous-course radiotherapy given concurrently, (3) radiotherapy, given with altered fractionation and the same concurrent chemotherapy. There was a trend towards a better survival in the group in which early radiotherapy was given concurrently with chemotherapy. A shorter treatment radiotherapy cycle, using hyperfractionated accelerated irradiation during concurrent radio-chemotherapy, was more effective than conventional fractionation, whereas alternating radio-chemotherapy schedules were as effective as concurrent schedules, leaving overall treatment time of radio chemotherapy constant. The data show that scheduling of radiotherapy and chemotherapy is important in the treatment of a fast proliferating tumour such as SCLC. Prolonged overall treatment with sequential radiotherapy and chemotherapy should be avoided. And there is every indication that an early onset of radiotherapy, concurrently applied to chemotherapy, is superior to a late onset [odds ratio of death within 2 years: odds ratio = 0.77 (0.60-0.99)]. There is a need to increase the effectiveness of radiotherapy over conventionally fractionated radiotherapy to 45 Gy, and this can be accomplished by using hyperfractionated accelerated radiotherapy.