Dr Lockie's Blog

Bariatric Surgery Helps To Lower Risks For GI And Other Cancers

6th November 2023

Many people know that being overweight increases the risk of health conditions like type 2 diabetes or heart disease.

But cancer? Cancer’s mostly linked to smoking or family history, isn’t it? Well, it turns out your weight significantly increases your risk of 13 different types of cancer. In fact, excess weight lies behind over 5,000 cancer cases each year.

New evidence suggests that bariatric surgery may help to lower the risk for many of those cancers.

What Cancers Are Associated With Obesity?

Many different cancers are associated with obesity, including cancers of the:

  • Breast (after menopause)
  • Bowel
  • Kidney
  • Liver
  • Endometrium
  • Ovaries
  • Stomach
  • Thyroid
  • Oesophagus
  • Gallbladder
  • Pancreas
  • Prostate
  • White blood cells (multiple myeloma).

How Does Excess Weight Increase Cancer Risk?

Excess weight affects far more than your clothing size. It leads to deposits of fat around your vital organs (known as visceral fat).

When your organs are surrounded by numerous, large visceral fat cells there’s little room for oxygen. That low-oxygen environment triggers long-term inflammation, which can disrupt your hormones – and that can increase your cancer risk.

How Excess Body Weight Increases Cancer Risk

  1. Too much body fat can trigger inflammation
  2. In response, the pancreas makes more insulin leading to elevated levels of insulin-like growth factor 1
  3. Extra fat cells also make more oestrogen
  4. Higher levels of insulin and oestrogen make cells divide more than usual
  5. Sometimes, those cells form cancerous tumours.

How Does Losing Weight Reduce Cancer Risk?

Researchers are still exploring that question but it seems that losing weight may, indeed, reduce cancer risk. One theory is that losing weight reduces inflammation and lowers levels of certain hormones that are linked to cancer risk – such as insulin and sex hormones like oestrogen.

Losing weight has other benefits too. Just a 5% reduction in your body weight can improve your health in numerous ways such as:

  • Reducing blood pressure and cholesterol
  • Improving sleep and relieving sleep apnoea
  • Improving type 2 diabetes
  • Easing pressure on your musculoskeletal system.

The trouble is that losing weight is hard. Keeping it off can be even harder.

Most people lose weight initially then plateau for a while before the weight piles back on. There are a few reasons for that. We live in an obesogenic environment that promotes large portions of unhealthy foods with sugary snacks tempting us everywhere.

Your body can also conspire against you. It likes to hold onto its weight. When you lose weight, your body may respond, most unhelpfully, by reducing your satiety signals and increasing your appetite!

It’s no wonder that an estimated 80-95% of dieters regain any weight they lose. And as your weight starts to increase again, so does your cancer risk.

Why Might Bariatric Surgery Help?

Bariatric surgery may help to power your weight loss by tilting the scales in your favour.

Weight loss surgery:

  • Changes your digestive system so that you feel full after smaller portions of food
  • Surrounds you with a skilled multidisciplinary support system, including doctors, dietitians, psychologists and exercise physiologists
  • Promotes fairly rapid weight loss initially – and that helps to sustain your motivation.

Bariatric surgery does carry some risks. During the operation, there are risks of bleeding, infection, blood clots or adverse reactions to the anaesthesia. And over the coming years, there are risks such as malnutrition, ulcers, gallstones and dumping syndrome (which leads to diarrhoea, nausea or vomiting).

Those risks, though, have to be weighed up against the risk of doing nothing. If the weight remains, you remain at high risk of serious (and deadly) health conditions such as cancer, heart disease and diabetes.

New Evidence About Bariatric Surgery And Cancer Risk

At Digestive Disease Week 2023, researchers presented the findings of a new study which showed that bariatric surgery could reduce the risk of developing obesity-related cancers.

This was a retrospective study where researchers used a large database of patients treated for various conditions at 47 American hospitals. They compared approximately 55,000 patients with obesity who had bariatric surgery against another 55,000 patients with obesity who did not have surgery. Then they tracked them through the system for 10 years to see which patients developed cancer. They also controlled for other risk factors that contribute to cancer formation, such as smoking history, alcohol use, heart disease, hormone therapies, and other comorbidities.

After 10 years of follow-up, 2,206 (4%) of the bariatric surgery patients had developed cancer, compared to 4,960 (8.9%) of the non-surgery patients with obesity.

Why did bariatric surgery make such a big difference? The study didn’t directly answer that question but we can speculate that perhaps bariatric surgery:

  • Made it easier to lose weight, which reduced inflammation and stabilised hormone levels
  • Enabled patients to keep the weight off over the next 10 years, which kept their cancer risk low.

A Lot Can Happen In 10 Years

One group of patients did not have surgery to address their weight. It’s possible they tried dieting but, as noted above, most dieters regain any weight they manage to lose. So, they probably remained overweight or obese and began to experience comorbidities such as diabetes, high blood pressure or heart disease in addition to their increased cancer risk.

The other group, however, had bariatric surgery and lost weight. If they followed the advice they were given, then they changed their diet and increased their activity levels. And they sustained those healthy lifestyle changes. That didn’t just reduce their cancer risk. It would have improved their overall health immensely and increased their quality of life.

How Can Dr Lockie Help?

Dr Lockie provides a multidisciplinary approach to weight loss surgery, ensuring you are supported by a skilled team of professionals as you seek to lose weight, improve your diet and develop a habit of regular exercise.

We know the first step is often the hardest one, so we’ve done our best to make it easier. We invite you to come and meet our wonderful staff for an informal orientation session where you can ask all your questions about bariatric surgery, finance options and ongoing support. You’ll come home with a free information pack to help you decide on your next steps.

Book your free session today.



All information is general and is not intended to be a substitute for professional medical advice. Dr Phil Lockie can consult with you to confirm if a particular treatment is right for you. Any surgical or invasive procedure carries risks.


AHPRA disclaimer

*All information is general in nature, patients should consider their own personal circumstances and seek a second opinion. Any surgical or invasive procedure carries risks

Note From Dr Lockie

Medications will be assessed pre-operatively and post-operatively. With weight-loss and particularly after surgery, comorbidities can change for the better, particularly e.g., hypertension or diabetes. It is essential for your health that medications are discussed with you, your GP and/or any other specialists such as Cardiologist or Endocrinologist etc.

In addition, use of multivitamins, and alternative supplements should be discussed with the practice to promote your better health.

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