Prognostic Significance of Circumferential Resection Margin following a Total Mesorectal Excision in Rectal Cancer

Baik, Seung Hyuk; Kim, Nam Kyu; Lee, Kang Young; Sohn, Seung Kook; Cho, Chang Hwan; Kim, Ho guen; Rha, Sun Young; Chung, Hyun Cheol

Abstract

PURPOSE: Studies of the circumferential resection margin (CRM) in rectal cancer surgery have revealed that inadequate surgical excision correlates with a high risk of recurrence. This study was designed to evaluate the prognostic value of the CRM in rectal cancer.
METHODS
All 504 patients who underwent a total mesorectal excision for rectal cancer between 1997 and 2001 were studied. The distance between the CRM and the tumor on pathology slides (HE stain, x 20 times) was measured. The CRM was stained by using the Davidson marking system(R) (Bradley Product, Inc. USA), and a micrometer was used for the measurement. We divided the patients into a negative CRM group (CRM >3 mm), an abutting CRM group (CRM < or =3 mm without involvement), and a positive CRM group (CRM was in the tumor), and compared the oncologic results among the groups.
RESULTS
The numbers of patients in the negative CRM, the abutting CRM, and the positive CRM groups were 452, 18, and 34 respectively. The mean follow- up durations were 45.1 months (range, 1.1~88.7), 41.9 months (range, 10.7~75.2), and 33.0 months (range, 4.8~83.4), respectively. The Aslter-Coller stages of all patients were from B2 to C3. The local recurrence rate, the systemic recurrence rate, and the combined recurrence rate were, respectively, 5.5%, 17.3%, and 3.8% in the negative CRM group (>3 mm), 5.6%, 38.9%, and 5.6% in the abutting CRM group, and 8.8%, 44.1%, and 8.8% in the positive CRM group. The five-year survival rates for the negative CRM, the abutted CRM and the positive CRM groups were 73.3%, 48.4%, and 25.5% (P<0.001), respectively, and the disease-free 5-year survival rates were 63.1%, 30.6%, 24.0% (P<0.001). The CRM was shown to be an independent prognostic factor by multivariate analyses adjusted for known predictors of outcome (P<0.001).
CONCLUSIONS
The prognosis for a member of the abutting or the positive CRM group was more unfavorable than it was for a member of the negative CRM group; therefore, measurement of the CRM should be reported in the pathologic report. For patients with an abutting or a positive CRM, neoadjuvant or adjuvant chemoradiotherapy should be considered for better oncologic outcomes.