Experience with a practical hyperfractionated accelerated radiotherapy regime

Abstract

n-field failure is still the most common problem for the radiation oncologist and there is significant room for improvement, even though newer techniques of tumor localization and sophisticated means of dose delivery could decrease marginal failures and improve tolerance. Models are evolving trying to understand the mechanisms of in-field failure. Accelerated tumor repopulation has been suggested as a cause of local failure. 1 Withers et al l suggest that the optimal treatment course should be approximately 4 weeks. We approximated that with 79.2 Gy in 4.5 weeks. Recently, experience originating in Mount Vernon Hospital 2'3 (described elsewhere in this issue) has apparently improved duration of survival and possibly local control in locally advanced bronchogenic carcinoma. That fractionation scheme uses three fractions per day separated by 6 hours, without the weekend breaks. The acute reactions are significant, and most of the treatments were given outside of the typical United States radiation oncology departmental hours of operation. Stimulated by this experience with continuous, hyperf rac t iona ted , accelerated radio therapy (CHART), 1'2 several investigators collaborated to develop a feasible program modifying CHART to practice in the United States. Our past experience using high doses of radiation, multiple treatment aids, and precision therapy in bronchogenic cancer have been disappointing. The local control rate at our institution has been 32% for patients with locally advanced bronchogenic cancer (AJC stages III and IV), with a 5-year, disease-free