Journal of Surgical Oncology 2008;98:611–615 Resection Margins in Modern Rectal Cancer Surgery NIR WASSERBERG, MD AND HAIM GUTMAN, MD* Department of Surgery B, Rabin Medical Center, Beilinson Campus, Petah Tiqwa and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel At present, the preferred treatment for rectal cancer is low anterior resection with total mesorectal excision and sphincter preservation. Complete removal of the tumor’s lymphatic and vascular pad with free resection margins has led to a reduction in rates of local recurrence and improved disease-specific survival. In addition to the distal and proximal margins from the tumor edge, for an optimal outcome, it is essential to consider distal mesorectal spread and the circumferential mesorectal margin. J. Surg. Oncol. 2008;98:611–615. ß 2008 Wiley-Liss, Inc. KEY WORDS: rectal cancer; resection margin; circumferential margin INTRODUCTION Adenocarcinoma of the rectum accounts for approximately 30% of all colorectal malignancies [1]. Stage- and location-dependent surgical excision with neoadjuvant chemoradiation is currently the best treatment option in most cases. For technical and disease-related reasons, abdominoperineal resection served as the standard procedure for low rectal cancer for many years [2]. The contemporary technique of total mesorectal excision (TME) with transanal anastomosis was introduced to improve local control and overall survival while preserving the anal sphincters and restoring bowel continuity in order to maintain the patient’s quality of life [3]. Recent studies report up to 70% sphincter preservation rates in patients treated with preoperative chemoradiation and TME-based resection [4]. Furthermore, compari- sons of patients after TME with historical controls treated with blunt rectal dissection have consistently shown lower local recurrence rates in the study group [5,6]. The earlier studies reported in a local failure rate of 35–45% [7], which has since been reduced to as low as 3%, with overall 80% 5-year survival [8–10]. The status of the resection margins is one of the most important factors determining disease recurrence after surgery [11,12]. The optimal distal margins required to achieve an adequate oncological outcome remain controversial. Moreover, while attention was traditionally addressed solely to the distal mucosal margins, not only have these margins been challenged and reduced significantly in recent years, but also circumferential margins and mesorectal margins have been attributed greater importance in achieving R0 resection. SURGICAL TECHNIQUE Rectal cancer must be completely removed with sufficient disease- free margins, including local vascular and lymphatic drainage vessels. The origin of the primary feeding vessel should serve as the level of proximal lymphatic ligation, that is, the superior rectal artery, which branches immediately at the bifurcation of the left colic artery. There is little evidence supporting ligation of the inferior mesenteric artery at its origin, although some studies reported a minor benefit in terms of local recurrence in a subset of patients [13–15]. The proximal and distal resection margins from the tumor are primarily derived from the level of vascular ligation. In 1954, Grinnell [16] found intramural extension in 12% of rectal and rectosigmoid cancer cases and recommended a minimum of 5 cm for the proximal and distal margins. However, although a 5-cm margin is feasible for proximal margins and for high rectal resections, it is more challenging if not impossible to achieve with sphincter preservation for lower rectal cancers. The mesorectum is defined as the lymphovascular, fatty, neural tissue circumferentially adherent to the rectum, starting from the level of the promontory, tapering down along the rectum, and ending at the level of the pelvic floor. Heald et al. [17] recommended the removal of the entire mesorectum. In a series of 100 patients with rectal cancer treated with TME he found tumor deposits in the mesorectum, 4 cm distal to the tumor edge. Current guidelines suggest the use of a sharp partial mesorectal excision (PME) to at least 4 cm distal to the tumor in patients with upper rectal cancer [15] and TME for patients with tumors in the middle and lower third of the rectum (0–10 cm from the anal verge; Fig. 1) [18]. TME should be performed along the embryologic avascular areolar plane, between the mesorectal fascia propria and the fascia of the pelvic sidewall [15]. This potential space between the fasciae has been termed the ‘‘holy plane.’’ Rectal mobilization is carried out by sharp dissection under direct vision. This technique is advantageous as not only does it include removal of the mesorectum containing the rectal draining lymph nodes, it also facilitates autonomic nerve preservation. By achieving the proper distal margin, and in addition, the proper circumferential margins (CRM)—which have gained increased atten- tion in recent years—TME optimizes the oncologic outcome and reduces the local recurrence rate [6,8]. The importance of macroscopic examination of a fresh rectal TME specimen cannot be overemphasized. Findings of a smooth surface, without incisions, tearing, or coning (consequent to the surgeon’s cutting towards the tubular rectum during distal dissection, rather than staying outside of the visceral mesorectal fascia [19]) in the distal *Correspondence to: Haim Gutman, MD, Department of Surgery B, Rabin Medical Center, Beilinson Campus, Petah Tiqwa 49 100, Israel. Fax: 972-3- 932-2118. E-mail: hgutman@clalit.org.il Received 20 February 2008; Accepted 27 February 2008 DOI 10.1002/jso.21036 Published online in Wiley InterScience (www.interscience.wiley.com). ß 2008 Wiley-Liss, Inc.