Dr Ganesh Ramalingam: Why do women with gynaecological cancers have a higher risk of colorectal cancer?

A recent report by the Singapore Cancer Registry1 found that colorectal cancer is one of the top three cancers diagnosed locally. In fact, the increasingly rampant cancer now accounts for 1 in 7 in Singaporean women (1 in 6 for men), with Chinese individuals being most at risk.

With similar research stating that women with gynaecological cancers have a higher risk of colorectal cancer, it is now more crucial than ever to arm ourselves with a good knowledge of colorectal cancer. What is it? Who does it affect? Why is it so common in Singapore, and why are women with gynaecological cancers at higher risk of developing colorectal cancer?

Firstly, what is colorectal cancer?

Colorectal cancer refers to the cancer of the colon (large intestine) and the rectum (the passageway that connects colon to anus). Colorectal cancer usually starts as a non-cancerous polyp (a small growth of tissue) on the inner lining of the colon or rectum. Such polyps may develop into cancer.

At an early stage, colorectal cancer often presents zero cancer symptoms. This is why it tends to be diagnosed only at a later stage – The Singapore Cancer Registry Annual Report 2015 states that roughly one-third of cases in Singapore are diagnosed at stage three, and a quarter at stage four.

Screenshot of Stage Distribution of Colorectal Cancel Patients

This is where colonoscopy screenings and other tests come in. Colonoscopies are crucial in detecting polyps and removing them before they become cancerous. 

Who does colorectal cancer affect?

The risk of developing colon cancer increases after the age of 50. So if you’re above the age of 50, you should most definitely be visiting your doctor for regular bowel screenings. 

If you say ‘yes’ to any of the statements below, I hope that you’re going for regular screenings:

  • I am above the age of 50
  • I have a family medical history of colorectal cancer
  • I have a medical history of bowel diseases
  • I have a genetic syndrome such as familial adenomatous polyposis, which causes small polyps to grow in my large intestine
  • I suffer from inflammatory bowel disease (eg. Crohn’s disease)
  • I have or have had a gynaecological cancer (eg. ovarian cancer)
  • I am overweight, smoke, or drink alcohol regularly
  • I consume a high-fat diet, or don’t exercise
  • I have Type 2 diabetes

If you’re a healthy young buck or mare, don’t get complacent either: The incidence of colorectal cancer in younger patients is ever-increasing, with roughly 1 in 10 Singaporeans who are diagnosed with the condition being below the ripe age of 50.

The moral here is: Don’t get lackadaisical about your health even if you’re young and seemingly healthy. Always, always, always see a doctor about any unusual symptoms. Early detection of cancer could save your life.

Read: Colonoscopy Screening in Singapore – Price, Procedure

Do women with gynaecological cancers really have a higher risk of colorectal cancer?

Studies2 have shown that women with gynaecological cancers are indeed at a higher risk of developing the condition. Unfortunately, both gynaecological and colorectal cancers share a few common risk factors, like lifestyle, obesity, and socioeconomic status. Thus, the risk of colorectal cancer should be of utmost concern to women who have gynaecological cancer.

It is also harder to detect colon cancer in women as their symptoms are often dismissed as gynaecological or menstrual issues. 

Research also states that:

  • CRC risks were higher for patients with ovarian cancer and endometrial cancer compared to for patients with cervical cancer.
  • Women with gynaecological cancers tended to have a higher incidence of colorectal cancer in the six months following their diagnosis.
  • The risk of colorectal cancer in women was the highest in the 12–24 months following the diagnosis of endometrial cancer3.

Why are they at higher risk of colorectal cancer?

While the exact mechanisms remain unclear, research has proven that gynaecological cancer and colorectal cancer share the same risk factors, including:

  • Obesity (estrogen levels are elevated in obese persons)
  • Hormone modulation, lifestyle, diet, and hereditary diseases
  • Not having given birth, and/or hormone replacement therapy
  • HNPCC (a condition in which the tendency to develop colorectal cancer is inherited)

Unsurprisingly, a decrease in exposure to estrogen may protect women from developing colorectal, endometrial, and ovarian cancer. 

Why colorectal cancer is so common in Singapore

There are several reasons why colorectal cancer is becoming increasingly prevalent, not just in Singapore, but the rest of the world. But let’s take a look at the factors that make this cancer a top killer here:

  • The average Singaporean in 2013 was 3kg heavier than someone from 1998.
  • Obesity rates are rising and have reached an all-time high since 2010.
  • Binge drinking has increased, especially in young adults and men.
  • 59% of Singaporeans eat more than their daily recommended calorie intake.
  • More than 400,0004 Singaporeans are diabetic.

The good news is that you have control of your lifestyle and habits, and can take many steps to help minimise your risk of developing colon cancer. While some of these changes might be hard initially, they will pay off endless dividends when it comes to your long-term health.

  • Quit smoking
  • Eat a balanced diet
  • Move and exercise
  • Cut down on alcohol

Regular colonoscopy screenings can help to prevent colorectal cancer

In a 2013 survey carried out by The Straits Times

  • Only 27% of Singaporeans are up to date with their screening, even know 90% know that a colonoscopy can save lives
  • 65% actually don’t believe they will get colorectal cancer
  • 45% feel like such things are best left up to fate
  • 83% thought that screening would be too expensive

The Singaporean layman cannot be blamed. After all, only 23% of Singaporeans surveyed had been advised by their doctors to go for a checkup. This is saddening, because in reality, men are 3.5 times more likely to get screened if advised by their doctor to do so. On the other hand, women are 2.5 times more likely to get a screening if someone in their family has colorectal cancer.

Colon cancer is actually one of the most preventable and treatable cancers if you are screened regularly and detect the condition early. In its initial stages, colon cancer cells are confined to the large intestine. And if these growths are detected and removed, they greatly lower your risk of colorectal cancer development.

As many of you already know, cancer treatment is most effective in the early stages. If cancer is detected at stage one, the survival rates are 84% for men and 86% for women. By stage four, this rate would have dropped steeply to just 10% for men and 11% for women.

I know a colonoscopy is never anyone’s idea of a fun time, but having one could save your life, and the lives of your loved ones.


  1. https://www.healthhub.sg/live-healthy/2056/9-Must-Know-Facts-About-Colorectal-Cancer 
  2. Srinivasan, R., Yang, Y. X., Rubin, S. C., Morgan, M. A., & Lewis, J. D. (2007). Risk of colorectal cancer in women with a prior diagnosis of gynecologic malignancy. Journal of clinical gastroenterology, 41(3), 291–296. https://doi.org/10.1097/01.mcg.0000225587.85953.06 
  3. Liao, S. C., Yeh, H. Z., Chang, C. S., Chen, W. C., Muo, C. H., & Sung, F. C. (2021). Colorectal Cancer Risk in Women with Gynecologic Cancers-A Population Retrospective Cohort Study. Journal of clinical medicine, 10(14), 3127. https://doi.org/10.3390/jcm10143127
  4. https://health-policy-systems.biomedcentral.com/articles/10.1186/s12961-021-00678-1#:~:text=In%20Singapore%2C%20over%20400%2C000%20Singaporeans,million%20by%202050%20%5B1%5D.

Dr Ganesh Ramalingam graduated from the National University of Singapore in 1997 and completed his post graduate training and Fellowship with the Royal College of Surgeons, Edinburgh. He is currently a Consultant General Surgeon with G&L Surgical Clinic, and specialises in General Surgery, Bariatric and Advanced Laparoscopic Surgery, Endoscopy, and Trauma.