Discovery sharpens ovarian cancer diagnosis

Paul Mayne//Western NewsAnatomy & Cell Biology PhD student Dylan Dieters-Castator said newly discovered protein biomarkers could soon help oncologists more accurately differentiate between two types of ovarian cancers, allowing for more precise treatment options.

Newly discovered protein biomarkers could soon help oncologists differentiate with near certainty between two types of ovarian cancers, thus allowing for more precise treatment options.

While current ovarian cancer tests have an accuracy rate of 90 per cent, they can always be better. More accurate classification means better treatments, explained Anatomy & Cell Biology PhD student Dylan Dieters-Castator.

“What we trying to do is bring that accuracy up,” he said.

Toward that end, researchers in a recent national study were able to compare protein expression in the various types of ovarian cancer and differentiate between them through a technique known as proteomics.

“While the pathologists can get it right most of the time, sometimes it’s hard to differentiate because the diseases share somewhat similar features,” Dieters-Castator said. “By using the eight protein bio-markers we have identified through our approach, we can actually pump that 90 per cent number up to more than 99 per cent.

“That means for those patients who have the most aggressive form, we are less likely to miss them. They will be able to be treated appropriately.”

Co-led by Western and the University of Alberta, the study included Dieters-Castator, Biochemistry professor Gilles Lajoie and Anatomy & Cell Biology adjunct professor Lynne-Marie Postovit, co-director of the Cancer Research Institute of Northern Alberta.

The two most common ovarian cancers are high-grade serous (70 per cent of cases) and endometrioid carcinoma (10 per cent of cases). While the latter has a relatively good prognosis and overall survival rate around 80 per cent after five years, the high-grade serous diagnosis, depending on the stage of the disease, has a survival rate of around 25 per cent in the same timeframe.

So while women with endometrioid-type usually have a better prognosis for beating the disease, and need a less aggressive treatment, the diagnosis can still be wrong 10 per cent of the time.

While it doesn’t sound like a big deal, it makes a huge difference when it comes to treatment, said Dieters-Castator. Not knowing with complete certainty which form of cancer the patient has means oncologists have to go with the harshest treatment regardless – a “one-size sits all” approach.

“With the most aggressive form, it would be treated as aggressively as possible, with surgery and chemotherapy,” he said. “Others can go through surgery but may not require chemo. There may be other approaches that can be taken into consideration.”

Dieters-Castator added these cancers tend to have other mutations. If researchers can better identify which type of tumour the patient has, they can apply the right genetic test to find out what mutation a particular patient might have.

“This might allow us to apply more precise treatment options, to see which is more susceptible to specific drugs,” he said. “Hopefully, future patients will benefit from something like this.”

The next steps will be to validate the results on a larger patient cohort and then suggest implementation, which could be within a few years.

The study, Proteomics derived biomarker panel improves diagnostic precision to classify endometrioid and high-grade serous ovarian carcinoma, was published in a recent edition of the journal Clinical Cancer Research.