The influence of the number of fractions and of overall treatment time on local control and late complication rate in squamous cell carcinoma of the larynx.

Three hundred and ten patients with T3/T4, N0, M0 squamous cell carcinoma were irradiated with 200 kV X rays with total doses ranging from 4,900 to 6,200 rad, given in 21 to 35 fractions in 32-63 days. After a minimum follow-up period of 3 years, the local control rate was 50%; 21 severe late complications were observed among the patients. The dependence of local control rate and of late complication rate on the dose per fraction and on overall treatment time was analyzed by various statistical methods. Whereas the late complication rate depended significantly on dose per fraction, local tumor control depended strongly on overall treatment time.