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 34.5 Gy/18f for face and neck port, with 1.92 Gy per daily fractionation; 2. The above regimen was followed by 1.25-1.50 Gy per fraction twice daily in 6-8 days for pre-auricular port; 3. The above regiment was then followed by conventional boosting dose 1.90 Gy and 1.30 Gy(morning 1.90 Gy and afternoon 1.30 Gy) twice daily(with inter- va[ of 6-8 hours) in 6-8 days. The whole course was 5 fractions per week with the median of 78 Gy over a median of 47 days. The positive and negative lymph node in the neck were treated by conventional radiotherapy with a me- dian of 67 Gy and a dose of 50-55 Gy 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 varieties 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 P<0.01; 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-come unconventional fractionation radiotherapy. Distant metastasis is the main reason of failure and death. (authors)