SPLIT-COURSE ACCELERATED THERAPY IN HEAD AND NECK-CANCER - AN ANALYSIS OF TOXICITY

Purpose: To retrospectively assess a protocol of split-course accelera ted radiation therapy (SCAT) for selected head and neck cancers. Metho ds and Materials: SCAT consisted of 1.8 Gy per fraction administered t wice daily with a minimum gap between fractions of 6 h. The treatment protocol prescribed an initial 16 fractions followed by a planned 5 to 12 day break, and then a further 20 to 22 fractions for a total dose ranging from 64.8 to 72 Gy delivered in 5 to 6 weeks. Results: Twenty- eight patients received SCAT for histologically confirmed head and nec k cancer between January 1987 and August 1991. All patients were follo wed up until December 1, 1993. The mean potential follow-up time was 4 .2 years (range: 2.9-6.2 years). All patients completed the treatment protocol. Thirteen tumors were laryngeal in origin, eight hypopharynge al, four paranasal sinus, and three oropharyngeal. There were no Stage I, three Stage II, nine Stage III, and 12 Stage IV tumors. Four tumor s were not staged (two paranasal sinus cancers and two surgical recurr ences). Early and late toxicities were moderate to severe. Confluent m ucositis was experienced by 27 of the 28 patients (96%). One patient r equired a prolonged midtreatment break of 24 days. Nine patients (32%) required narcotic analgesia for pain relief. Eleven patients (39%) re quired hospitalization for nasogastric feeding or pain control. The me dian length of hospital stay was 14 days (range 7-98 days). The actuar ial rate of severe late toxicity at 3 years was 47% (standard error (S E) = 13%). A complete tumor response was achieved in 86% of patients, The actuarial local control rate at 3 years was 43% (SE = 11%) and the actuarial survival rate at 3 years was 25% (SE = 8%). Conclusion: Giv en the encouraging complete response rate and local control for such a dvanced tumors, SCAT for locoregionally advanced tumors merits further investigation. However, because of the significant late toxicity obse rved, the total dose, interfraction interval, and fractionation techni que used should be reconsidered.