A "supralethal dose phenomenon" revealed by cancer of the maxillary sinus.

In this paper a so-called "supralethal dose phenomenon" is reported. Two groups of patients, all of whom were carrying proved squamous cell carcinoma of the same clinical stage in their maxillary sinuses, were compared after radiotherapy in our department. The radiotherapies applied to the two groups were very similar in terms of fraction number, treatment period, dose distribution and immobilization technique, but differed in dose, i.e., 5,500 cGy for one group of 9 patients and 5,750 cGy for the other group of 20 patients. The five-year survival rates of the two groups were 8/9 and 10/20, respectively, and the difference was statistically significant (p less than 0.05). All patients were observed for at least five years. Except for tumor stage, the status of the patients in the two groups, including primary site of the tumor in the sinus, patients' age and cause of death for the failed cases, are also discussed in detail.