Obesity and Biliopancreatic Cancers: Exploring Current Evidence

Abstract

Background: Pancreatic cancer (PC) is among foremost causes of cancer related deaths worldwide due to generic symptoms and lack of screening. The risk of developing pancreatic cancer in obese or overweight individuals is 1.5 times higher than individuals with a normal BMI. Bariatric Surgery has been associated with a reduction of obesity- related cancer, however, the number of cases that developed pancreatic cancer post Bariatric surgery is not known. Aim: Examine the relationship between Bariatric Surgery and Pancreatic cancer and identify reported cases of pancreatic cancer after bariatric surgery. Materials and Methods: A narrative review of the literature was conducted. A MEDLINE database search was performed using the following Medical Subject Headings (MeSH) terms: pancreatic cancer, bariatric surgery, weight reduction surgery, pancreatic adenocarcinoma. These were combined with the following: postoperative, after surgery, and during surgery. A WebScience search was then performed using similar terms. Additional references were then identified by manual search of the articles obtained from the MEDLINE and Web of Science. Cancer cases that were identified at the pre-operative period or intra-operatively were excluded. The searches covered the period from January 2000 to November 2020. Results/Review: Epidemiological evidence has shown that obesity as a risk factor for the development of PC is a dose dependent risk. The review found that the risk of developing pancreatic cancer in obese or overweight individuals is 1.5 times higher than individuals with a normal BMI. At the same time, evidence from literature demonstrated that weight reduction by dietary restriction, physical activities, pharmacotherapy or weight reduction surgery reduces risk of PDAC. A total of 24 cases of pancreatic cancer were identified and reported post Bariatric Surgery in the literature. The average age at diagnosis was 57.2 years and onset from surgery to diagnosis ranged from 2 months to 25 years. Of the identified cases, 23 cases were post Roux-en-Y Gastric Bypass and one case post Duodenal Switch. The review found that PDAC was the commonest reported pancreatic cancer post bariatric surgery accounting for 58.3%, followed by Neuroendocrine Tumours (NET) 16.7%. Conclusions: Along with weight reduction and improving comorbidities, Bariatric surgery reduces risk of obesity-related carcinogenesis. Given the variation in onset of diagnosis, bariatric surgery did not increase cancer risk but rather accelerated the diagnosis of pancreatic cancer.