Carcinoma of the larynx. V. Relationship between biologic effect and failure of irradiation

Among 147 patients with laryngeal carcinoma, treated with 60Co irradiation and followed for 5 to 10 years, there were 5 cases of recurrence due to incorrectly placed fields. The glottic cases consisted of one group below and one above a Partial Tolerance of 1 650 ret. In the latter group the recurrence rate was significantly lower than in the former. Higher ret levels did not lower the residual tumour or recurrence rate in the glottic group but seemed to lower the rate in the supraglottic group.