Bariatric Surgery and Obesity-Related Cancers

Introduction

Obesity is one of the significant risk factors for cancer development. Weight reduction can significantly reduce the incidence of cancer. Studies show that people who undergo bariatric surgery have a 32 percent lower risk than those who do not and a 48 percent lower risk of cancer death. Gallbladder, liver, ovarian, thyroid, and rectal cancers are found to be low in people who have undergone bariatric surgery.

What Is Bariatric Surgery?

Bariatric surgery includes gastric bypass and other surgeries for weight loss. The surgery changes how the digestive system functions, helping one lose weight. Some procedures limit food intake, while some reduce nutrient absorption. Some procedures include both of these. Bariatric surgery is performed when controlling diet and exercise under medical supervision has had no effect on weight loss or in cases of serious health issues.

What Are the Types of Bariatric Surgery?

There are mainly three types of bariatric surgery:

• Gastric Bypass: This is a commonly performed bariatric surgery when diet control and exercise have had no effect. In this surgery, a small pouch is created from the stomach connecting it directly to the small intestine. After the surgery, the swallowed food will go directly to the small intestine from this pouch without much absorption. It is an irreversible surgical procedure.

• Sleeve Gastrectomy: It is also called vertical sleeve gastrectomy. The procedure is laparoscopically performed in which multiple small instruments are inserted through the upper abdomen. During this procedure, 80 percent of the stomach is removed, and only a small tube (similar to the shape of a banana) of the stomach is left back. Removal of a major portion (80 percent) of the stomach will limit the amount of food one consumes and results in weight loss. It also helps in hormonal changes that help in weight loss.

• Biliopancreatic Diversion With Duodenal Switch: It is a less common surgery. It includes two steps. The first step is vertical sleeve gastrectomy, which removes 80 percent of the stomach and leaves only a banana-shaped tube behind. This pyloric valve (the valve that passes food to the small intestine) is left behind with the duodenum (the part that connects the stomach with the small intestine). In the second step of this surgery, a bypass is performed by connecting the final portion of the small intestine with the duodenum. This surgery can limit food consumption and decrease the absorption of nutrients, proteins, and fat. This procedure is very effective but poses risks like vitamin deficiency and malnutrition. It is mostly recommended for people with BMI (body mass index) above 50.

What Are the Indications for Bariatric Surgery?

• Bariatric surgery helps in weight loss and reduces weight-related health issues like increased blood pressure, heart disease, stroke, non-alcoholic fatty liver disease, sleep apnea, and type 2 diabetes mellitus.

• Bariatric surgery is indicated when a patient follows a healthy diet and exercise habits under medical supervision but is unable to lose weight.

• When the body mass index is greater than or equal to 40, it is called extreme obesity.

• If the body mass index is between 35 to 39.9, it is obesity and may give rise to weight-related health diseases like type 2 diabetes mellitus, increased blood pressure, or sleep apnea.

• People with a body mass index greater than 35 are qualified for bariatric surgery.

• In some cases, individuals with a body mass index between 30 to 34 accompanied by severe weight-related health problems are also qualified for the surgery.

What Are the Risks Associated With Bariatric Surgery?

• Excessive bleeding, infection, blood clots, and leakage in the gastrointestinal system during the surgical procedure can lead to fatality.

• The long-term complications and risks vary based on the weight loss surgery performed.

• There can be bowel obstruction, gallbladder stones, hernias, hypoglycemia (low blood sugar), malnutrition, gastric ulcers, nausea, vomiting, acid reflux, or diarrhea.

What Are the Post Bariatric Surgery Instructions?

After bariatric surgery, patients are instructed not to eat for one to two days to allow the digestive system and stomach to heal. After that, a proper diet should be followed for weeks, like drinking plentiful water to prevent dehydration, eating liquid meals every half hour, etc. Initially, the diet consists of only liquid food, progressing to soft foods, and then advancing to regular food after some weeks. The amount of food or drink intake is limited in portion, with frequent medical check-ups.

What Is the Association Between Bariatric Surgery and Obesity-Related Cancers?

• There is a significant association between bariatric surgery and obesity-related cancers. There is a lower risk of obesity-related cancer after bariatric surgery. And the death associated with cancer has also decreased.

• Obese patients can lose up to 20 to 30 percent of their body weight after bariatric surgery. Weight loss and cancer risk are indirectly proportional. If the weight loss is greater, there is a lower cancer risk.

• Excess weight is related to increased cancer rates. Obesity increases tumor growth by causing inflammation, altering the body's ability to use insulin to convert sugar from food into energy, and increasing sex hormone production that helps in the growth of cancers.

• Excess weight gain has a higher incidence and mortality in some cancers, but it is unknown whether intentional weight loss can reduce cancer risk.

• After bariatric surgery, either vertical sleeve surgery or gastric bypass, the rate of ovarian, uterine, or lung cancer has decreased compared to patients without surgery.

• Cancer development and growth increase with obesity. Several reasons were proposed and discussed for the development of cancer due to obesity, namely increased inflammation, increased adiposity, alterations in stable genes, and alterations in normal gut flora. Weight loss after bariatric surgery may influence these mechanisms.

• Obese people are more likely to get post-menopausal breast cancer as well as endometrial, liver, colorectal, pancreatic, and kidney cancer. Obese individuals need to be under a medically supervised diet and exercise schedule.

Conclusion

Bariatric surgery is not advisable for everyone. Several mandatory medical guidelines are required to be met. Several evaluative screening processes must be cleared before the confirmation for bariatric surgery can be obtained. One needs to incorporate a permanent diet and lifestyle modification. Repeat follow-up is required for people who undergo bariatric surgery. So these have to be taken into consideration before doing bariatric surgery.