Overall treatment time and the conventional arm of the CHART trial in the radiotherapy of head and neck cancer

Background and purpose. An analysis of the 366 patients treated with conven tional radiotherapy in the CHART randomized trial was performed to determin e whether prolongation of treatment time had any influence on tumour contro l or survival and to assess if this could have influenced the results of th e randomized comparison of CHART against conventional radiotherapy. Method: After a preliminary analysis the cases were divided into two groups according to duration of treatment. Results: Survival and primary tumour control showed small margins of deteri oration when the 232 patients who had been treated up to 48 days were compa red with 127 patients who had been treated in 49 or more days. These differ ences were not large with an estimated difference in 2-year survival of 8% and not conventionally statistically significant (P = 0.25); furthermore, t he survival difference was considerably reduced when the prognostic factors were taken into consideration in a Cox model. Conclusion: With a mean difference in treatment duration of 5.8 days, the m arginal differences observed between patients treated for longer and shorte r times are compatible with that which has been suggested in previous publi cations for the prolongation of treatment time in head and neck cancer. We conclude that the randomized comparison of CHART with conventional radiothe rapy is unlikely to be affected by conventionally treated patients who took longer than 48 days to complete their treatment. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.