Defining quality in colon cancer surgery.

Twenty years ago, there was a sudden burst of clarity regarding the treatment of rectal cancer. As stated by the 1990 National Cancer Institute–sponsored Consensus Development Conference, all stage II and III rectal cancers should be treated with postoperative chemoradiotherapy. The rationale for this consensus was strongly evidence based, with three separate studies (National Surgical Adjuvant Breast and Bowel Project [NSABP] trial R-01, North Central Cancer Treatment Group [NCCTG] trial 794751, and Gastrointestinal Tumor Study Group [GITSG] trial 7175) each showing an increase in diseasefree and overall survival after adjuvant chemoradiotherapy. Particularly striking was the effect of chemoradiotherapy on local recurrence, with combined-modality therapy halving the local recurrence rate in each of these trials. Yet almost as soon as these treatment recommendations were promulgated, they fell into disuse. What happened? The answer, in brief, was the recognition that careful anatomic surgery was the cornerstone of successful therapy. Just as the multimodality therapy studies were being published, Heald introduced the concept of total mesorectal excision (TME) and published data that demonstrated a 5% local recurrence rate with TME alone. These results compared favorably with the local recurrence rates seen after adjuvant chemoradiotherapy: 11% in the GITSG study, 13.5% in the NCCTG trial, and 8% in the NSABP study. Local recurrence was even higher in the surgery-alone arms of each of these studies: 24% in GITSG, 25% in NCCTG, and 13% in NSABP. Clearly, standard surgery was inadequate for rectal cancer. The TME concept is to completely and anatomically remove the entire lymphovascular pedicle of the rectum. This requires two components: central ligation of the blood supply and removal of an intact mesenteric package along the anatomic fascia-lined planes that have their basis in embryologic development. The major rationale for TME is to avoid pathologic involvement of the circumferential resection margin (CRM), a key risk factor for local recurrence. CRM positivity rates vary between surgeons, and surgeons with the lowest rates of CRM positivity have the lowest local recurrence rates. National programs to train and implement TME surgery have led to decreased local recurrence rates and improved rectal cancer survival. Local recurrence rates for rectal cancer vary with the plane of surgery achieved; the lowest rates occur when the correct mesorectal margin is followed. There is no disagreement about the concept of central vascular ligation (CVL), although the oncologic benefit of a high (origin of the inferior mesenteric artery) versus a low (superior rectal artery just below the take-off of the left colic) tie has not been conclusively demonstrated. In contrast to rectal cancer, the technical parameters of optimal colon cancer surgery have been little debated until recently. Likewise, there has been much discussion of centralizing rectal cancer referrals to expert surgeons in expert centers, but far less about similar centralization for colon cancer. Indeed, the tacit assumption has been that any reasonably trained surgeon should be able to properly remove a colon cancer. Unfortunately, emerging data have begun to belie this assumption. There has been broad acceptance of the concept that a minimum of 12 lymph nodes should be evaluated as a quality measure, and recent Surveillance, Epidemiology, and End Results data show that, despite improvements during the last 20 years, more than one in four patients still have inadequate resections by this standard. In addition, radiologic data document surprisingly incomplete mesenteric resections after conventional resections. The case is clear for TME in rectal cancer. But what about complete mesocolic excision (CME) with CVL in colon cancer? The approach has gained momentum in the last few years, but the concept is not new. For example, Stearns and Schottenfeld emphasized the need for “wide removal of the mesentery . . . down to its base” in 1971, and Bokey et al showed improved colon cancer survival in their practice after they introduced standardized anatomic dissection with high vascular ligation. Many surgeons now believe that the key to the success of the no-touch operation proposed by Turnbull et al was the initial central vascular ligation that occurred as the first step of the resection rather than the delayed tumor mobilization that Turnbull himself thought was responsible for his excellent results. In the article that accompanies this editorial, West et al expand on the emerging concept that extends the rectal cancer argument to colon cancer. Previous work from these investigators showed substantial variability in the plane of colon cancer surgery, with only 32% of resections at the Leeds General Infirmary being accomplished in the optimal mesocolic plane. There was a 15% overall survival advantage for patients with the optimal plane of surgery compared with those who had worst-plane resections, although this relationship did not hold up on multivariate analysis. Subsequent work by these authors compared surgical specimens after CME/CVL from Erlangen to specimens from conventional resections from Leeds. There were longer vascular pedicles, more mesocolic plane resections (90% v 40%), and a higher lymph node yield (median, 30 v 18) in the CME/CVL specimens. In this article, the authors compare resected colon cancer specimens from three institutions, one European and two Japanese, that JOURNAL OF CLINICAL ONCOLOGY E D I T O R I A L VOLUME 30 NUMBER 15 MAY 2