Colonoscopies and BRCA gene mutations... What’s the connection?

20 Aug 2021

There are many procedures you may be asked to undergo as a breast or ovarian cancer patient, however, treatment for these cancers are rarely a ‘one-size-fits-all' approach.

One of the procedures you might be asked to undergo may be a colonoscopy.

Why?

Well, medical oncologist Dr Jeffrey Goh, from Brisbane’s Icon Cancer Centre says there is a very specific reason why a small percentage of ovarian cancer patients may need to have one.

"There is a subtype of ovarian cancer, which is a less common, called endometriod ovarian cancer,” Dr Goh explains. “With this subtype, the cells look a little bit like uterine cancer under the microscope, but it originates from the ovary.”

Dr Goh says that with this particular type of ovarian cancer there is a connection to bowel cancer.

“With endometriod ovarian cancer, which is probably only 10% of cases, there is a link with bowel cancer through a genetic condition called Lynch Syndrome,” he explains.

However, he goes on to say that even if you are diagnosed with endometriod ovarian cancer, you may only be asked to undergo a colonoscopy if you have been tested for this condition, have a strong family of bowel cancer or if your faecal occult (screening) test was positive.

“Once you're diagnosed with endometriod ovarian cancer, we would do a test on your tumour to see if you are at risk of carrying the gene for Lynch syndrome,” he explains. “Then only if that's positive, would we recommend regular colonoscopic surveillance via Gastroenterologists.”

Dr Goh points out it’s not a procedure that is on the front lines of treatment straight away.

“There are quite a few steps before you might be asked to do a colonoscopy,” he explains. “You need to be diagnosed with an uncommon form of ovarian cancer and then on diagnosis, have a genetic test and if it's positive, then we need to confirm you actually have Lynch syndrome before you would then undergo a colonoscopy.”

However, while Dr Goh says colonoscopies aren’t standard recommendations for ovarian cancer patients, he points out that there is a separate government-funded faecal occult blood screening test for people aged 50 and above that is recommended; a positive stool test would lead to colonoscopy next to rule out colorectal cancer.

“So, after 50 years of age, Australian citizens will be sent a faecal occult blood test in the mail and they would do screening that way,” he explains. “So, they will need to do a stool test for traces of blood and if there were traces of blood in the stools, then they would need a colonoscopy. That is standard screening for every person above 50 years old, irrespective of whether they had ovarian cancer or not.”