Surgery Today | 2021
Complete mesocolic excision (CME) and D3-lymphadenectomy (D3) for right-sided colon cancers: a potentially prognostic surgical approach
Abstract
We were greatly impressed by the study of Sahara et al., which analyzed a population of 344 patients who underwent complete mesocolic excision (CME) and D3-lymphadenectomy (D3) for stage I-III right colon cancers [1]. In the patient subgroup affected by lymph node metastases (LNM; 150 = 43.6%), there was no significant variability in 5-year overall survival (OS) among the LNM group distribution (DLNM), being 71.1%, 78.7% and 50.4% for those with DLNM1 (pericolic nodes; 107 = 31.1%), those with DLNM2 (intermediate nodes; 30 = 28.7%), and those with DLNM3 (main nodes; 13 = 3.8%), respectively (p = 0.61) [1]. However, a significant variation in 5-year OS was recorded among the N-stage groups, being 86.6%, 76.2%, and 55.2% for N0, N1, and N2, respectively (p < 0.001) [1]. Among all the primary locations, the therapeutic indexes of lymphadenectomy were as follows: D1 = 22.1, D2 = 6.8 and D3 = 1.9 [1]. The study highlighted that N staging, based on the number of LNMs, prevails over DLNM for predicting the 5-year OS of patients undergoing CME + D3 for right colon cancers [1]. According to the authors’ findings, the benefit of survival from D3 was less than that from D1 and D2 lymphadenectomy, as far as the therapeutic index metric was concerned [1]. However, if compared with the therapeutic value, D3 may be more useful for predicting prognosis, based on the fact that it recovers a higher number of lymph nodes. In support of the prognostic and oncological prospective benefits of D3, Balciscueta et al. recently published the first meta-analysis aimed at assessing D3 shortand longterm outcomes of patients with right colon cancers [2]. They analyzed a population of 2592 patients, taking into consideration nine prospective and five retrospective studies comparing CME + D3 vs. classic right colectomy [2]. They highlighted that D3 leads to more complete surgical specimens, achieving a greater distance between tumor and vascular ligature (109.3 mm mean distance in the CME + D3 group vs. a 81.3 mm mean distance in the classic group; MD:26.7; p < 0.00001); a longer colonic resection (30.4 cm vs. 24.4 cm, respectively; MD:5.6; p = 0.002); a wider mesocolic resection (16.6 mm2 vs. 11.3 mm2, respectively; MD:52.31; p = 0.005), and a greater number of harvested lymph nodes (29.1 vs. 21 nodes, respectively; MD:7.67; p < 0.00001) [2]. The authors recorded prominent benefits in the long-term oncological outcomes of patients who underwent D3, including a reduced risk of local recurrence with 1.7% overall prevalence, in accordance with benefits described by the international guidelines, as well as a higher 5-year disease free-survival rate (HR:0.56, p = 0.03) [2]. Moreover, patients who underwent D3 had significantly better 3-year (HR:0.53, p = 0.004) and 5-year (HR:0.57, p = 0.003) OS rates, as well as significantly better 3-year and 5-year OS related to stage II (3-year HR:0.36, p = 0.03; 5-year HR:0.37, p = 0.04) and stage III (3-year HR:0.43, p = 0.008; 5-year HR:0.50, p = 0.01) disease. Nevertheless, lack of standardization, both in surgical approach and histopathological reporting, should be considered distinct methodological bias. In this direction, the standardization suggested by Garcia-Granero and collaborators is highly effective [3, 4]. Many other studies have * Maurizio Zizzo [email protected]