Mesenteric lymph node spread and optimal lymph node resection in colon cancer

Introduction Colon cancer is one of the most common forms of cancer world wide, with an incidence of almost 1 million cases anually. Surgery is a prerequisite for cure and the majority of patients are potentially curable at diagnosis. For a surgical resection to be curative the surgeon needs to remove the tumour together with all affected regional lymph nodes. How extensive the mesenteric resection has to be to ensure optimal survival and oncological results is under debate. International standardization of colon cancer surgery is warranted. The two contenders as future “gold standard” for colon cancer surgery are CME with CVL and Japanese D3 resection. Aim The aim of this thesis was to evaluate the impact of mesenteric resection and lymph node evaluation on survival in colon cancer. The aim of Paper I to IV was to: • Examine the impact of the introduction of a standardised pathological and anatomical (PAD) protocol on the quality of pathology and lymph node count. • Investigate if extended mesenteric resection in right-sided colon cancer improve long term survival and oncological results in a retrospective study. • Assess the impact of the extent of the mesenteric resection in right-sided colon cancer on long term survival, perioperative mortality and oncological outcome • Assess oncological outcome, survival and perioperative morbidity and mortality in sigmoid cancer depending on the height of the vessel ligation. Conclusions The quality of the PAD-report was improved by introduction of a standardised PAD protocol. Specimen dissection by a BMA increased the number of examined lymph nodes, improving the quality of pathology and possibly outcome. Extended mesenteric resection, in elective right hemicolectomy, did not improve survival or oncological outcome for cancer in the caecum or ascending colon. Instead extended mesenteric resection may increase 30 day postoperative mortality. For cancer in the sigmoid colon no survival benefit or decreased recurrence rate was found by more central ligation (HT) compared with ligation of the superior rectal (SRL) or sigmoid vessels (SR), in elective surgery. Our results question the routine use of extensive mesenteric resection in surgery of the right- and sigmoid colon and instead advocate a flexible surgical response guided by a deeper understanding of the tumor biology behind colon cancer