Detecting ovarian cancer before it spreads

The fight against ovarian cancer has not made much progress in recent decades. Researchers at McGill University believe they are on the verge of a big leap forward in this issue.

“Ovarian cancers are generally detected very late, at stage 3,” explains Lucy Gilbert, director of the department of oncology at McGill University. “Before there were no symptoms. »

Each year, the Canadian Cancer Society records 1,600 cases and 400 deaths of cervical cancer, compared to 3,000 cases and 2,000 deaths of ovarian cancer. The singer Mélanie Renaud, for example, died in May of ovarian cancer, at the age of 42.

“Before the Pap test, cervical cancer was the second deadliest for women in Canada,” says the gynecologist specializing in oncology. Today, more women die from ovarian cancer in Montreal than from cervical cancer in all of Canada. »

In 2012, the D^D Gilbert published in the Lancet Oncology a study that changed how she viewed the fight against ovarian cancer. Nearly 1,500 women had blood and transvaginal ultrasound screening for this cancer. “We were able to improve the results of surgery for cases of ovarian cancer, but the stage at which it was detected remained advanced. »

It was then that she realized that ovarian cancer migrates to other organs at an early stage. “In colon cancer, for example, the patient has bleeding and pain before the cancer emerges from the colon. Ovarian cancer travels from the uterus, through the fallopian tubes, to the abdomen before causing symptoms. The symptoms are linked to the presence of ovarian cancer metastases to the abdomen. »

Genetic analyzes

To detect ovarian cancer at an early stage, in order to reduce mortality, it is necessary to catch it when it consists of only a few cells, in the ovaries.

Just before the pandemic, the D^D Gilbert launched the DOvEEgene project for the early diagnosis of ovarian cancer. “Despite the interruption due to the pandemic, we recruited 4,600 participants while our objective was 3,600,” she says. About 90% of them had no family history of ovarian cancer. » Encouraging preliminary results are being presented this spring to granting agencies.

More than twenty mutations are detected by the analyses, following a vaginal sample. All ovarian cancers are caused by mutations, specifies the D^D Gilbert.

Since last fall, Quebec has been considering using a self-test for cervical cancer screening. Would this be possible for ovarian cancer? “No, because if the cancer cells have arrived in the vagina, where they can be collected by self-test, the cancer is already in an advanced stage. This is not the case for cervical cancer. »

On the other hand, she welcomes Quebec’s desire to set up the cervical cancer self-test program. “Ovarian cancer affects more wealthier socio-economic categories, who have fewer children, which is a protective factor. But cervical cancer affects more disadvantaged groups more. Often these are women who do not have a doctor, or time to see their doctor and have a Pap test. If we send them an easy-to-do self-test, with telephone follow-up, that should increase the screening rate. I believe that Quebec will be a leader on this point. »

Detecting cancer on a credit card?

On the other side of the Atlantic, a biologist from Imperial College London is trying another approach. Early 2023 in the magazine JMIR Public Health and Surveillance, he showed that it is possible to predict an ovarian cancer diagnosis from credit card purchase data. “Purchases of painkillers and antacids increase in the months or years preceding a diagnosis,” says James Flanagan, lead author of the study. We are now trying to see how to carry out a prospective study. There are obviously significant ethical issues. We would need access to purchasing data from thousands of women to prove that this is a valid approach. »

The D^D Gilbert isn’t convinced this approach will hold water. “When a woman has pain, the ovarian cancer has already migrated to other organs. So I don’t think it will detect cancers at an early stage. »