Should Right-Sided Colon Cancer Be Treated with Complete Mesocolic Excision?

Extensive lymph node dissection with complete mesocolic excision resulted in significantly improved recurrence and survival outcomes in colon cancer, according to the results of a new study¹ conducted in Denmark. The study compared extensive lymph node dissection with conventional resection in patients with right-sided colon cancer. 

Complete mesocolic excision involves meticulous dissection in the mesocolic plane with bowel resection at a minimum of 10 cm proximally and distally of the tumor, and central vascular ligation to ensure lymph node dissection around the superior mesenteric vessels. 

“Complete mesocolic excision is more challenging than conventional resections because of the complex vascular anatomy of the right colon, and many surgeons have refrained from performing right-sided complete mesocolic excision, although it seems to be a safe procedure,” wrote study authors led by Claus A. Bertelsen, PhD, of Nordsjællands Hospital in Hillerød, Denmark.

Other studies of this procedure have not had an intent-to-treat design or were designed to show causal effects. Thus, the investigators conducted a population-based cohort study involving prospectively collected data from four hospitals in Denmark; they included a total of 1069 patients with stage I-III right-sided colon cancer who underwent either complete mesocolic excision (256 patients) or more conventional resection with unstandardized and limited lymph node dissection (813 patients).             

The mean time to last follow-up examination was 3.80 years, and no patients were lost to follow-up. The groups were well matched, with a median age of approximately 74 years in both groups, and a body mass index of 24.6. The surgery was conducted by a specialist in 100% of the complete mesocolic excision group and in 96% of the conventional resection group (P = 0.0003).            

A total of 145 patients in the conventional group (17.9%) had a recurrence, compared with 25 patients in the complete mesocolic excision group (9.7%). The absolute risk reduction with complete excision over the full 5.2-year study period was 8.2% (P = 0.00015). In the control group, 281 patients died during follow-up (35%), compared with 75 patients in the complete mesocolic excision group (29%).            

The rate of 60-day major postoperative complications was similar, at 17% in the conventional group and 18% in the complete mesocolic excision group (P = 0.85). Thirty-day and 90-day mortality were also similar between the 2 groups.

 “The findings of this study suggest a causal treatment effect of complete mesocolic excision can reduce the risk of recurrence after resection for right-sided UICC stages I–III colon adenocarcinoma,” the authors concluded. “On the basis of our findings, we advocate standardisation of surgery for right-sided colon cancer by performing complete mesocolic excision.”

In an accompanying editorial, Nicholas P. West, MB, CHB, of St James's University Hospital in Leeds, United Kingdom, wrote that the study did have some limitations. The researchers focused solely on right-sided colon cancers, with no long-term follow-up for distal transverse and left-sided tumors, and they did not include analysis of the key determinants of mesocolic excision quality, including mesocolic plane and vascular ligation height. Still, he wrote that the authors should be congratulated. 

“All medical teams treating colon cancer should be encouraged to refocus on their practice to ensure that long-term outcomes improve in line with those reported for rectal cancer,” West wrote. “Perhaps now might be the time for a change in practice.”

References:

Bertelsen, C., Neuenschwander, A., Jansen, J., Tenma, J., Wilhelmsen, M., Kirkegaard-Klitbo, A., Iversen, E., Bols, B., Ingeholm, P., Rasmussen, L., Jepsen, L., Born, P., Kristensen, B. and Kleif, J. (2019). 5-year outcome after complete mesocolic excision for right-sided colon cancer: a population-based cohort study. Lancet Oncology.