Prognosis of late-course unconventional fractionation radiotherapy for nasopharyngeal carcinoma

Objective To study retrospectively the outcome and failing factors of nasopharyngeal carcinoma(NPC) treated with late-course unconventional fractionation radiotherapy(LCUCFR). Methods From January 1996 to December 2000, 133 such patients were analyzed retrospectively. All had been confirmed by histopathology as poorly differentiated squamous cell carcinoma, including 101 males and 32 females. All were treated by LCUCFR. The nasopharyngeal lesion radiation schedule was as follows; 1.An initial conventional fractionation 34.5Gy/18f for face and neck port, with 1.92Gy per daily fractionation;2.The above regimen was followed by 1.25-1.50Gy per fraction twice daily in 6-8 days for pre-auricular port;3.The above regiment was then followed by conventional boosting dose 1.90Gy and 1.30Gy(morning 1.90Gy and afternoon 1.30Gy) twice daily(with interval of 6-8 hours) in 6-8 days. The whole course was 5 fractions per week with the median of 78Gy over a median of 47days. The positive and negative lymph node in the neck were treated by conventional radiotherapy with a median of 67Gy and a dose of 50-55Gy in median interval of 43 days. Results The 5-year nasopharyngeal lesion and neck metastasis lymph node control rate was 92.9% and 96.4%, respectively. T1,T2,T3 and T4 stage local control rate was 100%,96.6%,96.6% and 78.4%,respectively. The overall 5-year survival and disease-free survival rate was 73.3% and 70.8%,respectively. The 5-year distant-free metastasis rate was 80.2%. Fourteen varietes were used to analyze the prognosis. Both univariate and multivariate analyses revealed that the distant metastasis, lower neck and superclavicle area as well as both neck lymph node metastases and local recurrence were prognostic factors for 5-year survival rate(Logrank test all P0.01;Cox test P=0.000,0.016,0.044, 0.041). Conclusions The 5-year primary control rate and survival rate of nasopharyngeal patients can be improved with late-course unconventional fractionation radiotherapy. Distant metastasis is the main reason of failure and death.