Split-course versus continuous radiotherapy

A randomized clinical trial was performed from 1964 to 1967 to compare the therapeutic results of split-course external beam radiotherapy with those of continuously fractionated treatment. Altogether 439 consecutive patients with carcinoma of larynx, nasopharynx, hypopharynx, oropharynx, oral cavity, oesophagus and urinary bladder were included in the series. 227 patients received split-course treatment and 212 were treated by the continuous-course method. In the split-course treatment there was a 2-3 weeks' interruption after 25-30 Gy. This break was compensated by a 10% increase in the total dose. For each tumour site local control and failure rates for the 2 treatment techniques were similar. No significant differences in 5- and 10-year survival were noted. Acute side effects were milder in all patients treated with split-course. The occurrence of late reactions was similar in both treatment groups. However, severe late reactions in the urinary bladder were somewhat more in patients treated with split-course technique; the difference was not statistically significant. We conclude that there were no significant differences in local control, long-term survival and late normal tissue reactions between the treatment groups. The acute normal tissue reactions were milder in the split-course treated groups. We still regard split-course as a useful treatment modality provided the interruption is compensated with about 10% increase in total dose. However, more studies are needed to show which tumours proliferate during prolonged radiotherapy. (orig.)