Result of hyperfractionation

Recent improvements in radiobiological data suggest that higher therapeutic gains may result from the hyperfractionation method rather than the conventional one. Using this data, a test was carried out using intermittent irradiation three times per day at four-hour intervals; 60-100 cGy was used for each fraction with high cumulative doses of 70-75 Gy over 6.5-7.5 weeks. This method was applied mainly to urologic and head and neck tumors, and tumors of limited cases such as T-1, 2, or N minus were well controlled. However, in extended cases with T-3, 4 or N plus, the results were almost the same as conventional ones; and the tumor control rate was not improved with increased total doses, but acute injuries showed a significant increase. (author)