What is the Significance of the Circumferential Margin in Locally Advanced Rectal Cancer After Neoadjuvant Chemoradiotherapy?

• Published in: Annals of surgical oncology Vol. 20; no. 4; pp. 1179 - 1184
• Main Authors: Trakarnsanga, Atthaphorn, Gonen, Mithat, Shia, Jinru, Goodman, Karyn A., Nash, Garrett M., Temple, Larissa K., Guillem, José G., Paty, Philip B., Garcia-Aguilar, Julio, Weiser, Martin R.
• Format: Journal Article
• Language: English
• Published: New York Springer-Verlag 01.04.2013; Springer Nature B.V
• Subjects: Adenocarcinoma - mortality; Adenocarcinoma - pathology; Adenocarcinoma - therapy; Adolescent; Adult; Aged; Chemoradiotherapy; Colorectal Cancer; Female; Follow-Up Studies; Humans; Male; Medicine; Medicine & Public Health; Middle Aged; Neoadjuvant Therapy; Neoplasm Metastasis; Neoplasm Recurrence, Local - diagnosis; Neoplasm Recurrence, Local - mortality; Neoplasm Staging; Oncology; Prognosis; Prospective Studies; Rectal Neoplasms - mortality; Rectal Neoplasms - pathology; Rectal Neoplasms - therapy; Risk Factors; Surgery; Surgical Oncology; Survival Rate; Young Adult; Local Recurrence; Total Mesorectal Excision; Distant Recurrence; Rectal Cancer; Circumferential Radial Margin
• ISSN: 1068-9265; 1534-4681
• DOI: 10.1245/s10434-012-2722-7

Background The circumferential resection margin (CRM) is highly prognostic for local recurrence in rectal cancer surgery without neoadjuvant treatment. However, its significance in the setting of long-course neoadjuvant chemoradiotherapy (nCRT) is not well defined. Methods Review of a single institution’s prospectively maintained database from 1998 to 2007 identified 563 patients with locally advanced rectal cancer (T3/T4 and/or N1) receiving nCRT, followed after 6 weeks by total mesorectal excision (TME). Kaplan-Meier, Cox regression, and competing risk analysis were performed. Results The authors noted that 75 % of all patients had stage III disease as determined by endorectal ultrasound (ERUS) and/or magnetic resonance imaging (MRI). With median follow-up of 39 months after resection, local and distant relapse were noted in 12 (2.1 %) and 98 (17.4 %) patients, respectively. On competing risk analysis, the optimal cutoff point of CRM was 1 mm for local recurrence and 2 mm for distant metastasis. Factors independently associated with local recurrence included CRM ≤1 mm, and high-grade tumor ( p  = 0.012 and 0.007, respectively). CRM ≤2 mm, as well as pathological, nodal, and overall tumor stage are also significant independent risk factors for distant metastasis ( p  = 0.025, 0.010, and <0.001, respectively). Conclusion In this dataset of locally advanced rectal cancer treated with nCRT followed by TME, CRM ≤1 mm is an independent risk factor for local recurrence and is considered a positive margin. CRM ≤2 mm was associated with distant recurrence, independent of pathological tumor and nodal stage.