Liu M T, Yeh C Y
Department of Radiation Oncology, Chang-Hua Christian Hospital, Taiwan.
Radiat Med. 1998 Mar-Apr;16(2):113-7.
Epstein-Barr virus (EBV) is a ubiquitous human herpes virus with worldwide infection. It is associated with Burkitt's lymphoma in Africa and nasopharyngeal cancer (NPC) in Asian countries. EBV-coded DNA was found to be present in epithelial elements of NPC, and is usually associated with non-keratinizing (WHO type II) or undifferentiated carcinoma (WHO type III). Transcriptional analyses of EBV genome expression in NPC demonstrate an activated viral state in some of these tumors, leading to elevated levels of serum anti-viral capsid antigen (VCA) antibody in NPC patients.
Eighty patients with histological diagnoses of NPC according to the 1978 WHO classification were referred to the Department of Radiation Oncology at Chang-Hua Christian Hospital for curative radiotherapy from 1985 to 1995. The patients were staged according to the AJCC staging system. A mean dose of 7,020 cGy in 39 fractions was delivered to the primary tumor using a telecobalt-60 unit or 6-10 MV X-ray linear accelerator. Pre- and postradiotherapy serum levels of anti-EBV/VCA IgG and IgA were determined for all patients using the indirect immunoperoxidase assay (IPA). Multivariate analysis was done to determine which factors affected the patients' treatment outcome and survival.
Five patients were excluded from this study due to incomplete radiotherapy, leaving 75 patients eligible for analysis. Overall local control was 77.3%, with a mean disease-free interval of 19.7 months. Factors affecting local control included radiation dose and pretreatment anti-EBV/VCA IgG titer. The overall 5-year actuarial survival for the 75 patients was 75%, with a median survival of 129.5 months. The 5-year actuarial survival rates for stage I + II, III, and IV patients were 90%, 40%, and 45%, respectively. Prognostic factors for survival included tumor histological type and pretreatment anti-EBV/VCA IgA titer, while prognostic factors for local control included total radiation dose received and pretreatment anti-EBV/VCA IgG titer.
We found that there was a significant difference in the geometric mean titer of anti-EBV/VCA IgA antibodies before and after radiotherapy. Prognostic factors affecting NPC patients' actuarial survival included tumor histology and pretreatment IgA titer, while prognostic factors for local control of NPC included total radiation dose received and pretreatment IgG titer.
爱泼斯坦-巴尔病毒（EBV）是一种广泛存在的人类疱疹病毒，全球均有感染。它与非洲的伯基特淋巴瘤以及亚洲国家的鼻咽癌（NPC）相关。已发现EBV编码的DNA存在于NPC的上皮成分中，通常与非角化型（WHO II型）或未分化癌（WHO III型）相关。对NPC中EBV基因组表达的转录分析表明，其中一些肿瘤处于病毒激活状态，导致NPC患者血清中抗病毒衣壳抗原（VCA）抗体水平升高。
1985年至1995年间，80例根据1978年WHO分类经组织学诊断为NPC的患者被转诊至彰化基督教医院放射肿瘤科接受根治性放疗。患者根据美国癌症联合委员会（AJCC）分期系统进行分期。使用远距离钴-60装置或6-10MV X射线直线加速器对原发肿瘤给予平均剂量7020cGy，分39次照射。使用间接免疫过氧化物酶测定法（IPA）测定所有患者放疗前后血清中抗EBV/VCA IgG和IgA水平。进行多因素分析以确定哪些因素影响患者的治疗结果和生存。
5例患者因放疗不完整被排除在本研究之外，其余75例患者符合分析条件。总体局部控制率为77.3%，平均无病生存期为19.7个月。影响局部控制的因素包括放射剂量和治疗前抗EBV/VCA IgG滴度。75例患者的总体5年精算生存率为75%，中位生存期为129.5个月。I + II期、III期和IV期患者的5年精算生存率分别为90%、40%和45%。生存的预后因素包括肿瘤组织学类型和治疗前抗EBV/VCA IgA滴度，而局部控制的预后因素包括接受的总放射剂量和治疗前抗EBV/VCA IgG滴度。
我们发现放疗前后抗EBV/VCA IgA抗体的几何平均滴度存在显著差异。影响NPC患者精算生存的预后因素包括肿瘤组织学和治疗前IgA滴度，而NPC局部控制的预后因素包括接受的总放射剂量和治疗前IgG滴度。
