Long-term observation after radiotherapy for nasopharyngeal carcinoma (NPC).

One thousand one hundred twenty-seven cases of nasopharyngeal carcinoma were treated with routine radiotherapy from October 1969 to March 1976, of which 436 cases have survived for more than 5 years, 323 cases have survived for over 10 years. The follow-up rate was 98.4%. The present paper analyzes the factors involved in these 436 cases. All patients were treated with tele60Co unit, and in the neck some cases were treated with orthovoltage therapy. The total dose to the primary lesion was 60-75 Gy in 6-8 weeks and in a few cases over 80 Gy were needed, and 50 Gy were applied bilateral cervical lymphatic chain. In this series of cases the 10-year overall survival rate was 28.7%, with Stage I being 66.7%, Stage II 46.5%, Stage III 28.0%, and Stage IV 18.6%, respectively. Statistically, 68 cases died of cardiovascular and other diseases and should be eliminated for net survival calculations. Therefore, we could obtain an actual 10-year survival rate of 30.5%. However, it should be noted that most of these cases were advanced, with Stage III, IV accounting for 82.3%, thus at Stage I, II the 10-year survival rate was 48%, while at Stage III, IV rate was down to 24.5%, which was statistically significant (p less than 0.01). Local and cervical recurrence as well as distant spread of diseases, for these cases started from the fifth to the tenth year after radiotherapy, the mortality caused by the above-mentioned three sites together was 76.9%. According to these findings, we propose that follow-up after radiotherapy in NPC exceeds 10-years. Of the 323 NPC cases, 10 were nasopharyngeal local recurrence which were re-irradiated, accounting for 3.1%. This paper shows that the 3-year survival rate in the local recurrence which were re-irradiated was 34.5%, the 5-year survival rate was 14.8%, and the 10-year survival rate was 11.5%. The failure after re-irradiation was caused by local recurrence and metastasis with a mortality of 83.6%. These results emphasize that the success of initial irradiation is important.