Analysis of Prognostic Factors according to WHO Classification for Thymic Epithelial Tumor

흉선종의 WHO 분류에 따른 예후인자의 임상적 고찰

  • 서영준 (계명대학교 의과대학 동산의료원 흉부외과) ;
  • 금동윤 (계명대학교 의과대학 동산의료원 흉부외) ;
  • 권건영 (계명대학교 의과대학 병리학교) ;
  • 박창권 (계명대학교 의과대학 동산의료원 흉부외과)
  • Published : 2004.08.01

Abstract

Background: Primary thymic epithelial neoplasm is a type of mediastinal tumors that have various biologic and morphologic features. In this study, we reclassified 59 cases of thymic epithelial tumors by the new WHO classification. We inquired whether the new WHO classification has independent prognostic relevance by analyzing clinical characteristics of thymic epithelial tumors including Masaoka's clinical stage. Material and Method: From December 1986 to August 2003, 59. patients who underwent surgery in the Keimyung University Dongsan Medical Center with definite diagnosis of thymic epithelial tumor were studied. We analyzed the histologic subtype (WHO classification). clinical stage (Masaoka's clinical stage) and patient's characteristics (sex, age, myasthenia gravis, tumor size, invasion. recurrence, metastasis) as prognostic factors. We analyzed the relationship between histologic subtype and clinical stage. Result: 32 patients were male and 27 were female. Mean age was 50.1$\pm$14.2. From WHO A to C, all thymic epithelial tumors were reclassified by the new WHO classification. Six patients (10.2%) had Type A, 7 (11.9%) had Type AB, 7 (11.9%) had Type B$_1$, 10 (16.9%) had Type B$_2$ and 7 (11.9%) had Type B$_3$, 22 (37.3%) had Type C. Two factors were shown by multivariate analysis to be associated with a favorable prognosis: completeness of resection (p=0.003) and non-invasiveness (p=0.001). The overall 5-year survival of the 59 patients was 53%, subtype A and AB were 92.3%, B$_1$ and B$_2$ were 70.2%, and B$_3$ and C were 26.1%. The association between histologic subtype and invasive behavior (stage) was statistically significant (p<0.001). Conclusion: The WHO classfication is not only a histologic classfication of the thymic epithelial tumors but also a significant prognostic factor that influence the survival of thymic epithelial tumors.

배경: 원발성 흉선상피세포종(primary thymic epithelial neoplasm)은 다양한 생물학적 및 형태학적인 특성을 가진 종격동 종양이다. 이 연구에서는 59예의 흉선종 환자를 새로운 WHO분류에 따라 재분류하고, Masaoka 임상적 병기를 비롯한 여러 가지 임상적인 특성을 분석함으로써 예후에 영향을 미치는 인자를 알아보고 WHO 분류가 독립적인 예후인자가 될 수 있는지를 알아보고자 했다. 대상 및 방법: 1986년 12월부터 2003년 8월까지 계명대학교 동산의료원에서 흉선종으로 진단 받은 후 수술적 치료를 받은 59예를 대상으로 생존율에 영향을 미치는 예후인자를 흉선종의 조직학적 분류(WHO classification)와 임상적 병기(Masaoka's clinical stage) 및 환자의 특성(성별, 나이, 중증근무력증 유무, 종괴의 크기, 종괴의 침습 유무, 재발, 전이)에 따라 분석하였다. 그리고 조직학적 분류와 임상적 병기사이의 연관성을 분석하였다. 결과: 남자는 32예, 여자는 27예였으며 평균연령은 50.1$\pm$14.2세였다. 모든 흉선종은 WHO 분류에 따라 A부터 C까지 재분류하였다. WHO 분류에 따라 Type A는 6명(10.2%)이었고 AB는 7명(11.9%), B$_1$은 7명(11.9%), B$_2$는 10명(16.9%), B$_3$는 7명(11.9%), C는 22명(37.3%)으로 나타났다. 여러 가지 임상적 특성 가운데 다변수 분석을 통해 완전절제(p=0.033)와 주변조직으로의 저침습성(p=0.001)이 좋은 예후와 연관이 있는 것으로 나타났다. 전체 흉선종의 5년 생존율은 53%였으며 WHO 분류에 따른 5년 생존율은 Type A+AB가 92.3%, B$_1$+B$_2$가 70.2%, B$_3$+C가 26.1%로 나타났다. WHO 조직학적 분류와 생존율 사이의 상관관계분석에서 WHO 조직학적 분류는 예후와 통제적으로 유의하게 연관성이 있는 것으로 나타났다(p<0.001). WHO 분류에 따른 Masaoka 임상병기 분석에서도 두 변수가 통계적으로 유의하게 연관성을 가지는 것으로 나타났다(p<0.001). 결론: WHO 분류는 단순한 조직학적인 분류일 뿐만 아니라 흉선종의 생존율에 중요한 영향을 미치며 종양의 침습성을 잘 반영하는 예후인자임을 알 수 있었다.

Keywords

References

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