수술전 화학방사선 요법을 시행 받은 직장암에서 혈중 암종배아항원과 조직학적 치료반응도와의 상관관계분석

Abstract

Purpose : This study was designed to assess whether serum CEA is associated with pathological tumor response in rectal cancer patients who underwent preoperative chemoradiation therapy (CRT) with total mesorectal excision (TME).

Methods : Eighty-five patients with rectal cancer who were treated by preoperative CRT followed by TME were enrolled between August 2005 and December 2007. 5-FU based chemotherapy and 5040 cGy of radiation were delivered. Serum CEA was measured pre-CRT, post-CRT, and post-TME period. Among 85 patients, 29 patients did not have post-CRT CEA level. Pathological tumor response (ypTNM stage) was categorized into two groups as follows; favorable response group (group A: n=28, pathological complete response and ypTNM I) vs unfavorable response group (group B: n=57, ypTNM II and III). Median follow-up period was 29.2 months (range 1.1-50.2 months).

Results : There were no differences between favorable and unfavorable response group with respect to age, gender, tumor location, lymphovascular invasion, and perineural invasion (Table 1). Anal sphincter preservation surgery was more commonly performed in the group A when compared with group B (26 (92.9%) vs. 41 (71.9%)) (p=0.026). Well and moderately differentiated histology were more commonly found in the group A (26(92.9%) vs. 40(70.2%) (p=0.018). Low level of pre-CRT CEA (<5ng/ml) was more commonly found in the group A (26(92.9%) vs. 30 (52.6%) (p=0.000). However, there was no difference between group A and B with regard to post-CRT CEA and post-TME CEA. Logistic regression analyses showed that pre-CRT CEA (<5ng/ml) and sphincter preservation surgery were associated with favorable pathological tumor response.

Conclusions : Low level of pre-CRT CEA (<5ng/ml) is predictive of favorable pathological tumor response but serum level of post-CRT and post-TME CEA did not have significant association with tumor response. This result should be validated in larger prospective randomized study near future.