專題討論10:放射腫瘤的新進展與質子治療
      Advances in radiation oncology and proton therapy

程 序 表

S10-5
血漿EB病毒定量是鼻咽癌診療之理想生物標記
林進清
台中榮總放射腫瘤部

  鼻咽癌與一般頭頸鱗癌有許多不同,包括流行病學、病理組織學、臨床表徵、治療策略、和對治療之反應。鼻咽癌很早就被證明與EB病毒有密切關聯,例如EB病毒DNA幾乎100%存在所有鼻咽癌原發腫瘤與轉移病灶內。鼻咽癌沒有很好的腫瘤標記,過去許多文獻報告以血清抗EB病毒抗體做為診斷鼻咽癌的標幟,根據我們的經驗和一些文獻發現:鼻咽癌病人治療後,即使腫瘤獲得控制,但血清抗EB病毒抗體仍持續高於正常人,當鼻咽癌復發或轉移時,驗血結果抗EB病毒抗體並不會特別升高,因此血清抗EB病毒抗體無法有效監測鼻咽癌病情變化。最近十多年來,利用即時性定量聚合?連鎖反應檢測血漿EB病毒DNA含量,可做為鼻咽癌病人臨床診療之理想生物標記以及一般人篩檢標記,包括困難病例之鑑別診斷、導引適當的治療策略、治療後監測病情變化、及早預測治療療效…等。
  Nasopharyngeal carcinoma (NPC) is distinguished from other cancers of the head and neck with regard to epidemiology, histological features, clinical characteristics, treatment strategies, and response to therapy. NPC has been proven as an Epstein-Barr virus (EBV)-associated cancer. EBV genome is present in the cells from almost every primary and metastatic NPC, regardless of the degree of tumor differentiation or the geographic origin of the patients. The anti-viral capsid antigen or anti-early antigen IgA antibody (IgA-VCA or IgA-EA), measured by indirect immunofluorescence or ELISA is one of the most widely used markers in assisting the diagnosis and for screening of NPC. However, the sensitivity and specificity are not good. Most patients have persistent high titer of IgA-VCA or IgA-EA after treatment although clinical surveys show no evidence of recurrence. Recent development of the real-time quantitative polymerase chain reaction assay allows us to detect plasma EBV DNA fragments in most newly diagnosed NPC. In addition, the plasma EBV DNA is rarely detected in healthy people and long-term survivors of NPC without relapse. Recent studies support that the plasma EBV DNA really is an idea biomarker in the clinical management of NPC patients. It covers a broad spectrum of clinical use, including screening in health people, differential diagnosis for suspected new cases and post-treatment difficult cases, treatment strategy guidance, post-treatment monitoring, early prediction of tumor response and survival in recurrent/metastatic disease.