The design of phase III palliative chemotherapy trials in head and neck cancerThis paper describes a series of 2447 patients with squamous carcinoma of the head and neck treated personally over 22 years; 276 patients with advanced untreatable disease and 498 with recurrent untreatable disease are analysed. The median survival for the first group was 13 weeks and for the second 11 weeks. The data fitted an exponential curve. Prognostic factors included general condition and N status for the first group, and site of the primary tumour, site of the recurrence and length of time to recurrence for the second group. However, these factors only explained 5% of the variance; the remaining 95% was unexplained, emphasizing the futility of stratification for prognostic factors, and the necessity for large trials. Using the above facts the number of patients required for a trial, and the length of the trial, can be worked out, and tables of these are given.