Tritiated thymidine studies of radiated laryngeal cancer.

CLINICAL evaluation of the effectiveness of radiotherapy on advanced cancer of the larynx has proven precarious. 1 We are familiar with patients in whom sizeable tumors have disappeared clinically following radiotherapy, only to reappear and necessitate attempts at salvage. Similarly, microscopic nests of apparently viable cells often appear in the larynges of patients who have received tumoricidal range dosages of radiation followed by laryngectomy and neck dissection. 2 Since the effects of radiotherapy are determined primarily by ionizing events within cells, it is logical that this treatment be followed at cellular and radiobiologic as well as clinical and pathologic levels. To this end we are currently using tritiated thymidine autoradiography to monitor the effects of preoperative radiation on the death and recovery of cancer of the larynx. 3 Cell viability can be established unequivocally by the presence of intranuclear tritium, and more important, predictions of the behavior of radiated tumor