Obesity and FAP requiring proctocolectomy in elective situations – surgical considerations

Obesity is the fastest growing disease worldwide in the last few decades. Among its effects, it increases the risk and mortality of cancer in several organs. 

In fact, nowadays it is thought that around 20% of all cancers can be attributed to obesity. Several obesity-associated conditions have been positively associated with cancer in the gastrointestinal tract.

The adenomatous polyposis coli (APC) gene is a key tumor suppressor gene. Mutations in APC have been found in ∼60% of sporadic carcinomas and adenomas, while germ-line mutations in the APC gene result in familial adenomatous polyposis (FAP). Recent studies published in the literature have examined the promotion of carcinogenesis in the gastrointestinal tract in relation to obesity: hypermethylation of APC promoter 1A, genetic and epigenetic events in APC, hyperinsulinemia and high IGF-1 concentrations in blood due to the increase in visceral fat are key factors in the relation between obesity and carcinogenesis.

In this surgical open classroom, we will consider two scenarios regarding surgical considerations. The first one is the diagnosis of FAP in an obese patient in need of elective proctocolectomy, while the second one is when a patient with previous bariatric surgery is diagnosed of FAP or an attenuated form of FAP.

In the first case, technical considerations will be analyzed, taking into account the increase in complexity and surgical complications that obese patients who need to undergo a restorative proctocolectomy with ileal pouch-anal anastomosis will be exposed to.

Secondly, an analysis of the possible complications that patients with previous bariatric surgeries who have to undergo proctocolectomies due to FAP will be performed, with special focus on patients with previous mixed or malabsorptive techniques with duodenal exclusion.