Success of elective irradiation of occult lymphatic metastases from cancers of the larynx and pyriform sinus.

We determined the success of elective neck irradiation for 104 patients with carcinomas of the larynx and pyriform sinus whose only surgery was resection of the primary cancer. Tumor regrew in the neck of 22 patients (21%) and was twice as likely to recur in the neck when there was simultaneous regrowth of tumor in the laryngeal remnant or pharynx. The observed rate of neck recurrence did not vary appreciably from the expected rate as determined by the incidence of occult lymphatic metastases in dissected neck specimens. The rate of neck recurrence was less after high doses (greater than 45 Gy) than low doses (less than or equal to 45 Gy) of irradiation, suggesting a benefit from higher doses of elective neck irradiation.