Obesity and Cancer Risk – What are the Facts?

Obesity and Cancer Risk – What are the Facts?

The disease of obesity is an ever-increasing problem for the health of our population. The number of people struggling with obesity is set to rise exponentially in the coming years. Many people don’t realise that obesity is a health issue and treating it focuses on simply improving health and achieving a healthier weight for you.

Obesity is now outstripping smoking as a risk factor for many cancers. This is a startling statistic that highlights the health risks of living with obesity and the need for effective treatments. Nearly all of the evidence linking obesity to cancer risk comes from large cohort studies, a type of observational study.

An International Agency for Research on Cancer (IARC) Working Group concluded that the evidence is consistent that higher amounts of body fat are associated with an increased risk of a number of cancers.

This table summarises the risks for some common.

Cancer type (reference) Compared with people without obesity or overweight, this cancer is 
Endometrial 7 times as likely in people with severe obesity
2–4 times as likely in people with obesity or overweight
Esophageal adenocarcinoma 4.8 times as likely in people with severe obesity
2.4–2.7 times as likely in people with obesity
1.5 times as likely in people with overweight
Stomach cancer 2 times as likely in people with obesity
Liver 2 times as likely in people with obesity or overweight
Kidney 2 times as likely in people with obesity or overweight
Pancreatic 1.5 times as likely in people with obesity or overweight
Colon and Rectal cancer 1.3 times as likely in people with obesity
Breast Postmenopausal 1.2–1.4 times as likely in people with obesity or overweight
1.2 times as likely for every 5-unit increase in BMI

People who have a higher BMI at the time their cancer is diagnosed or who have survived cancer also have higher risks of developing a second, unrelated cancer.

How might obesity increase the risk of cancer?

Several mechanisms have been suggested to explain how obesity might increase the risks of some cancers

  • Fat tissue produces excess amounts of estrogen, high levels of which have been associated with increased risks of breast, endometrial, ovarian, and some other cancers.
  • People with obesity often have increased blood levels of insulin and insulin-like growth factor-1 (IGF-1). High levels of insulin and IGF-1 may promote the development of colon, kidney, prostate, and endometrial cancers.
  • Obesity can cause chronic inflammation and this can cause DNA damage and increases the risk of

There are other possible mechanisms by which obesity can increase cancer risk.

Are many cancers due to obesity?

The proportion of cancers due to excess body weight is approximately 7% or 8% of all cancers diagnosed in high-income Western countries. 

Does losing weight lower the risk of cancer?

To better understand the relationship between weight loss among people with obesity and cancer risk, research has looked at cancer risk in people with obesity who have undergone bariatric surgery.

Studies have found that bariatric surgery among people with obesity, particularly women, is associated with reduced risks of cancer overall; of hormone-related cancers, such as breast, endometrial, and prostate cancers; and of obesity-related cancers, such as postmenopausal breast cancer, endometrial cancer, and colon cancer.

The Benefits of Bariatric Surgery

So, it is clear that obesity increases cancer risk for a broad spectrum of cancers. Weight loss reduces this risk. It is just one further way in which weight loss surgery is beneficial for improved long-term health and improved life expectancy.

Weight loss surgery is not a decision to be taken lightly but has significant health benefits for patients struggling with the chronic condition of obesity. Surgery can be a life-changing decision. It can improve not only quality of life but long-term health.

Blackrock WeightCare offers surgical treatment of obesity. Contact us to discuss your options.

Your Health. We Care.