Cyclooxygenase-2 expression in rectal cancer predicts poor prognosis for patients receiving postoperative chemoradiation
Other Titles
수술 후 항암화학방사선 치료를 받은 직장암환자에서 Cyclooxygenase-2 발현의 임상적 유용성
Authors
김준원
Department
Dept. of Radiation Oncology (방사선종양학교실)
Issue Date
2011
Description
Dept. of Medicine/석사
Abstract
Purpose: The objective of this retrospective study was to determine the role of cyclooxygenase-2 (COX-2) expression in pre-irradiation rectal cancer specimens as an indicator of prognosis for patients undergoing postoperative chemoradiation.Patients and Methods: We performed immunohistochemical (IHC) study with COX-2 antibody on the pre-irradiation surgical specimen obtained from 72 patients who were treated with postoperative chemoradiation for locally advanced rectal cancer between 2000 and 2001. IHC scores were assigned based on both intensity and extent of staining, and patients were divided into two groups: a COX-2 positive group (IHC score ≥ 5, n = 27) and a COX-2 negative group (IHC score < 5, n = 45). Clinicopathologic parameters, patterns of failure and survival rates were compared between the two groups. Univariate and multivariate analyses were performed to determine the prognostic factors influencing patient survival.Results: Median follow-up was 65 months. COX-2 overexpression was observed in 37.5% of patients. Locoregional failure rates were higher in the COX-2 positive group (25.9% vs. 6.7%, p = 0.02) as well as distant metastasis (48.1% vs. 17.8%, p = 0.006) in comparison with the COX-2 negative group. The 5-year disease free survival (DFS) and overall survival (OS) rates were lower for the COX-2 positive group compared with the COX-2 negative group (DFS: 46.8% vs. 76.7%, p = 0.019 / OS: 54.1 % vs. 85.9%, p = 0.026). Univariate and multivariate analyses of DFS and OS showed that COX-2 overexpression was an independent prognostic factor that surpassed other well-known clinicopathologic parameters.Conclusions: COX-2 overexpression in pre-RT surgical specimen was strongly associated with a higher rate of treatment failure and can be used as a potent molecular risk factor predicting poor prognosis for locally advanced rectal cancer patients receiving postoperative chemoradiation.
[한글]
목적: 근치적 수술 시행 후 얻은 국소진행성 직장암 조직에서의
cyclooxygenase-2 (COX-2)의 발현 정도가 수술 후 항암화학방사선치료
시행 후 환자의 예후에 미치는 영향을 분석하고자 후향적 연구를
시행하였다.
재료 및 방법: 2000년부터 2001년까지 국소진행성 직장암으로 근치적
수술과 수술 후 항암화학방사선치료를 시행한 72명의 환자의 수술
조직을 대상으로 COX-2에 대한 면역조직화학 염색 (IHC stain)을
실시하였다. 염색의 강도 (intensity)와 범위 (extent)를 조합하여 IHC
score를 정의하였고 27명의 COX-2 양성군 (IHC score ≥5)과 45명의
COX-2 음성군 (IHC score <5)으로 구분하였다. 두 군에 속한
환자들간의 임상 및 조직학적 인자, 재발양상, 생존율을 비교하였고
환자의 생존에 영향을 미치는 예후인자를 일변량 및 다변량 분석을
통해 확인하였다.
결과: 추적관찰기간의 중앙값은 65개월이었다. COX-2 과발현은 37.5%의 환자에서 관찰되었다. 국소재발율 (25.9% 대 66.7%, p =
0.02)과 원격전이율 (48.1% 대 17.8%, p = 0.006)에서 모두 COX-2
양성군이 음성군보다 높은 것으로 확인되었다. 5년 무병생존율 (46.8%
대 76.7%, p = 0.019)과 전체 생존율 (54.1% 대 85.9%, p = 0.026)에