Extent of surgery in cancer of the colon: Is more better?

Table 1 Variables confounding the association between nodal count and survival in colorectal cancer

Confounding variables		Effect on LNC
Patient characteristics	↑Age, ↓socioeconomic status, non-Caucasian race	↓
	gender, body mass index	?
Tumor characteristics	↑Tumor diameter, T stage, overall cancer stage, lymphocytic infiltration, MSI-H phenotype	↑
	↑Tumor grade	↓
	Mucinous differentiation, lymphovascular and perineural invasion	?
Surgical factors	Open vs minimally invasive resection	None
	Colorectal vs general surgeons, advanced fellowship training	↑
	Surgeon volume	?
Institutional factors	High-volume centers, teaching hospitals, significant CC surgical practice, academic pathology laboratories	↑
	Preoperative radiochemotherapy for rectal cancer	↓
Factors related to pathology examination	Xylene/alcohol fat clearance, embedding of the entire mesentery vs traditional dissection, ex vivo intra-arterial methylene blue injection, tattooing of neoplasms during colonoscopy, pathologists interested in CRC, use of a standardized protocol to evaluate CC specimens	↑

LNC: Lymph node count; CC: Colon cancer; CRC: Colorectal cancer; MSI: Microsatellite instability.

Table 2 Clinical studies comparing limited with extensive surgery for colon cancer

Ref.	Year	Country	Design	Location	Stage	n	Surgical technique	Node count	Node postivity rate	Survival
West et al[42]	2012	Japan/Germany	Retrospective multicenter study	Colon	I-IV	254	D3 resection vs CME	More nodes after CMEa	No difference	Not investigated
Hashiguchi et al[31]	2011	Japan	Retrospective single center study	Colon	I-IV	914	Left hemicolectomy with variable extent of lymph node dissection	More nodes after vertical dissection	No difference	Shorter if no vertical node dissection. No influence of main node removal or extent of horizontal node dissection
West et al[30]	2010	United Kingdom/Germany	Prospective and retrospective multicenter study	Colon	I-IV	89	Hemicolectomy vs CME	More nodes after CMEa	No difference	Not investigated
Tentes et al[29]	2007	Greece	Prospective single center study	Left colon	I: 10.5% II: 42.7% III: 40.3% IV: 6.5%	124	Left hemicolectomy vs left hemicolectomy + periaortic lymphadenectomy	More nodes after radical resection	No difference	No difference except longer survival after radical resection for stage III
Tagliacozzo et al[28]	1997	Italy	Retrospective single center study	Right Colon	I: 24.3% II: 35.4% III: 40.3%	144	Right hemicolectomy vs right hemicolectomy + retropancreatic lymphadenectomy	More nodes after radical resection	No difference	No difference
Rouffet et al[27]	1994	France	Prospective multicenter study	Left colon	I-IV	260	Left segmental colectomy vs left hemicolectomy	Not investigated	Not investigated	No difference

CME: Complete mesocolic excision.