Tumour regression during radiation treatment as a guide to prognosis.

The response to radiation treatment was studied in 110 patients with head and neck cancer with a minimum follow-up of two years. If the tumour had disappeared by the mid-point of treatment (3000 rad), a significantly more favourable prognosis was found in early (T1-2N0) tumours. On the other hand, whether these tumours had disappeared or were persisting at the end of treatment, there was no difference in the recurrence during the observation time of two years. In advanced tumours there was no significant relationship between disappearance by the mid-point of treatment and recurrence up to two years. But when an advanced tumour had disappeared at the end of treatment, the prognosis was significantly more favourable. The unpredictability and often impossibility of judging the prognosis in individual cases encourages the authors to stress the importance of executing the original individual surgical plan irrespective of radiation response.