Comparison of long-term results of conventional fractionation radiotherapy and late course accelerated hyperfractionation radiotherapy for nasopharyngeal carcinoma of stage T_(3～4)N_(0～1)M_0

Objective To evaluate and compare the long-term therapeutic effects of conventional fractionation(CF) radiotherapy and late course accelerated hyperfractionation(LCAHF) radiotherapy in treatment for nasopharyngeal carcinoma(NPC) of stage T3～4N0～1M0. Methods Clinical data of 358 patients with NPC at T3～4N0～1M0 stage who underwent radiotherapy were retrospectively analyzed,with 172 in CF group and 186 in LCAHF group.Two large lateral opposing fields were first used to treat nasopharynx and upper neck at a fraction of 2 Gy daily,5 d per week.After 36～40 Gy,two small lateral opposing fields were used to boost the primary tumor with the spinal cord shielded.In CF group,the accumulated total dose of nasopharynx was 74～78 Gy.In LCAHF group,the radiation fraction of primary tumor was 1.5 Gy twice daily,with 6-8 h interval in the late course.The accumulated total dose was 72～78 Gy.Results The 3-,5-and 8-y primary site control rates were 78.5%,65.3% and 53.4% in LCAHF group;and 68.8%,51.7% and 41.4% in CF group(P 0.05).The 3-,5-and 8-y survival rates were 75.0%,56.9% and 45.4% in LCAHF group,and 70.4%,53.9% and 42.0% in CF group(P 0.05).Further analysis showed that LCAHF improved the primary site control rate of T 3 NPC(P 0.01),but not of T 4 NPC.No significant difference in the acute radiation toxicities and sequelae was observed between the two groups(P 0.05).Conclusion Compared with CF radiotherapy,LCAHF improves local control rate and is also more tolerable;however,the long-term survival is similar between two protocols.