目的：本研究之目的在分析鼻咽癌病患接受體外放射線治療，但局部治療劑量在4500cGy下之情形。材料與方法：從1979年4月至1997年12月，共有138位鼻咽癌病患在林口長庚醫院接受體外放射治療劑量4500cGy以下，且之後並未於他院接受放射線治療或化學治療等。其中男性103人、女性35人，年齡分布放18歲至85歲之間，箅咽的治療劑量介於180cGy至4500cGy間；中位劑量(median dose)為2500cGy。使用Kaplan-Meier之方法來決家其生存期。結果：這138位病人的追蹤期間從3年至14.7年不等，其追蹤之中位數為7.1年。直至2001年12月底止，仍存活者共有7人，其中5人是無病存活；130人已死亡，而其中77人(56%)死於局部腫瘤，38人(27.5%)死於遠處轉移，14人(10%)死於惡病質，1(0.7%)人死於腦中風；1人失去聯絡一年及五年之整體存活率分別為52%及11%；中位存活期為1.06年，而大部分之病人都於中斷治療後2年內死亡。結論：研究結果顯示鼻咽癌病患接受局部放射治療劑量只有4500cGy以下者其預後是很差的，大部分病患於治療中斷後之2年內死亡，而造成病患治療中斷主要導因乃是病患無法忍受放射治療所引起急性副作用之故。

Purpose: To study the outcome of undertreated nasopharyngeal carcinomas (NPC) in patients who received external beam radiation doses of no more than 4500 cGy. Materials and Methods: Form April 1979 to December 1997, 138 NPC patients receiving radiotherapy with external beam radiation (EBRT) doses of no more than 4500 cGy at the Department of Radiation Oncology, Chang Gung Memorial Hospital, Linkou, were included in this study. Total doses ranged from 189 cGy to 4500 cGy with a median dose of 2520 cGy. The survivals were calculated by Kaplan-Miere method. The median follow-up time was7 years. Results: At the time of last follow-up, the 1– and 5-year survival rates for the 138 undertreated NPC patients, derived using the Kaplan-Miere method, were 52% and 11%, respectively. One hundred and twenty-nine patients had died of the disease. One patient had died of intercurrent disease. Five patients were alive without disease. Two patients were alive with disease. One patient was loss of follow-up. The median survival of these patients was 1.06 years (range from 0.03 ~ 19.7 year). At the end of study, local recurrent or persistent tumors were determined for 94 patients (68%). Forty-nine patients (35.5%)subsequently developed distant metastases. The causes of death were: locoregional disease: 56% (n=77),distant metastasis:27.5%(n=38), cachexia:11% (n=15), cerebrovascular accident:0.7% (n=1). Bone. Liver and lung were the most common metastatic sites. Most of the patients died within two years after interruption of treatment. Death was the only outcome evaluated. Less than 5% patients (n=5) were alive without disease till the time of analysis. Discussion: The prognosis has been dismal for undertreated NPC patients. Our study confirmed that long-term survival is rare in patients with NPC receiving EBRT doses not more than 4500 cGy. The majority of patients died within 2 years after interruption of radiotherapy (RT). The acute side effects and complications of RT were the primary factors influencing the patient’s decisions to drop out of the treatment.