Ottawa researchers find diabetes drug has potential to prevent ovarian cancer

It's early days, but Dr. Barbara Vanderhyden is hopeful a discovery by her team at the Ottawa Hospital Research Institute could eventually be used to fend off ovarian cancer. 

Common Type 2 diabetes medication metformin halts scarring in ovaries, Ottawa Hospital team discovers

Dr. Barbara Vanderhyden led the laboratory team at the Ottawa Hospital Research Institute that discovered the common diabetes medication metformin could help prevent the development of ovarian cancer. (Francis Ferland/CBC)

It's early days, but Dr. Barbara Vanderhyden is hopeful a discovery by her team at the Ottawa Hospital Research Institute could eventually be used to fend off ovarian cancer. 

In a laboratory study published in the medical journal Clinical Cancer Research, the team found metformin, a common medication to treat Type 2 diabetes, may be able to halt and possibly reverse scarring of the ovaries that occurs with age — one of the primary risk factors for ovarian cancer.

"There is a lot yet to be proven, but if it is successful, then we could see metformin used as a preventive measure in about five years," Vanderhyden said.

Metformin is a widely used drug prescribed to regulate blood glucose levels in diabetics. But doctors gradually noticed the drug also appears to reduce the rate of ovarian cancer among those patients.

There are no effective tests for early ovarian cancer, and symptoms are subtle. (World Ovarian Cancer Day)

Grim diagnosis

Vanderhyden's research team proposes that beyond treatment for those diagnosed with ovarian cancer, metformin could possibly stop the disease from occurring in the first place.

Ovarian cancer is the fifth-most common cancer in women. It's also the deadliest, with a mortality rate of 65 per cent among women who develop the disease. Ovarian Cancer Canada estimates 2,800 Canadian women will face those grim odds in 2019 alone. 

Currently, the only method of prevention for young women with a genetic predisposition to the disease is to remove their uterus, ovaries and fallopian tubes, "which is a rather harsh method of prevention," Vanderhyden said. 

Dr. Curtis McCloskey, the lead author of the study, was a PhD student at the University of Ottawa Research Institute at the time of the discovery. He's now a postdoctoral fellow at Toronto's Princess Margaret Cancer Centre. (Curtis McCloskey)

The research

The laboratory team examined 27 ovaries taken from women ages 21 to 87.

Fibrosis was apparent in the ovaries of postmenopausal women, leading the researchers to conclude that fibrosis of the ovaries is an inevitable and natural part of aging. 

Older women with ovarian fibrosis, or a stiffening of the ovaries, have a higher risk of developing ovarian cancer. 

"Cancer cells tend to like growing in these fibrotic tissues," said Dr. Curtis McCloskey, the lead author of the study. 

The researchers found fibrosis develops with age in the ovaries (middle panel), which may be linked to an increase in ovarian cancer risk. The team found ovaries from post-menopausal women taking metformin did not have fibrosis (third panel). (Ottawa Hospital)

The exception

But there was one notable exception that caused the researchers to take a second look.

"There was one 69-year-old ovary that had no evidence of fibrosis, which didn't make sense," Vanderhyden said.

"So we went back and looked at her file and found that she was actually taking a drug called metformin." 

Vanderhyden's team collected more ovaries from other women taking metformin and found that none had any evidence of fibrosis, even if they were postmenopausal. The antidiabetic drug appeared to prevent the normal aging of the ovary.

Vanderhyden is hoping in the future metformin, which is relatively inexpensive drug, will prove to be an effective treatment for younger woman who have a high risk of ovarian cancer, but don't want to remove their ovaries because they still want to have children. 

Elaine Taggart, pictured with her husband, Keith, underwent chemotherapy for ovarian cancer four years ago. (Elaine Taggart)

Hope for a breakthrough

Since Elaine Taggart was diagnosed with ovarian cancer four years ago, she has endured chemotherapy and a hysterectomy, and continues treatment as an outpatient at the Ottawa Hospital. Taggart is hoping the research can help prevent other women from going through the same thing.

"I'm going to go tell my daughters about it and make sure they can they can get on a drug like that," Taggart said.

Dr. Lucy Gilbert, director of the Women's Health Research Unit at McGill University Health Centre, welcomes the study and calls the research important. 

According to Gilbert, clinical trials on metformin are rare because the inexpensive drug provides little profit for pharmaceutical companies.

Dr. David Morris, associate professor in the departments of medicine and gynecology at McGill University, said he's pleased to see research that backs up what many doctors are already observing.

"It's a good study that has been done in an important medical area which is going to confirm the use of a very simple medication to prevent disease." Morris said.

Morris says he's observed health improvements in his patients with polycystic ovary syndrome who were treated with metformin.

With file from The Canadian Press.