VANCOUVER -- Trish Keating's cancer was a particularly vicious breed of monster.

Her colorectal cancer diagnosis in 2010 was followed by a repeating cycle of surgeries, chemotherapy, radiation and, when she and her doctors thought they had finally slain the beast, relapses.

Keating, who worked as costume designer in the film industry, was told in late 2013 that the cancer had returned once again and this time it was terminal. She might have two or three years to live.

Last fall, Keating, 67, joined a clinical trial in Vancouver that sequenced the genome of her tumour to recommend treatment. She was put on a drug typically used to treat high blood pressure and within five weeks the cancer was barely detectable.

"When you've lived with cancer for five years and you're trying to beat the dragon that's breathing behind you, when finally someone says to you 'We can't see any (cancer)', first of all you're incredulous, kind of in a state of shock," Keating said in an interview.

"It takes a while. It took me and my husband a couple of days for that to set in."

Keating's doctor treated her as part of a B.C. Cancer Agency study into personalized onco-genomics, or POG -- an experimental method of examining tumours to identify potential treatment.

While the technique could be years away from widespread clinical use, the researchers hope it could one day allow doctors to customize treatments to each patients' individual tumours and improve their odds of survival.

Dr. Howard Lim said that in Keating's case, the genomic sequencing identified a specific protein as the driving force behind her cancer. His team identified an existing blood-pressure medication known to block pathways to that protein.

"I remember it was right after New Year's and I gave her a call," Lim said, recalling when he received the first test results after five weeks of treatment with the new drug.

"The results came to my desk and I couldn't believe it."

At the two-month mark, Keating's cancer was undetectable and she is considered in remission.

Lim said cancer is currently treated based on its type -- colon cancer is typically treated with colon cancer drugs, for example.

But he said that approach fails to recognize patients with the same type of cancer may have tumours that act very differently -- and respond to different treatment.

"Therefore, we can't treat all colon cancers the same," Lim said.

"What we're trying to do is tailor and personalize chemotherapy."

That also means the blood-pressure medication used to treat Keating's tumour -- which Lim described as unique -- won't necessarily help other colorectal cancer patients. Most of the time, the genomics testing recommends some form of traditional chemotherapy, he said.

Lim said researchers still need to determine whether using the POG technique to guide treatment improves survival rates when compared with standard chemotherapy. He said it's also not clear whether it will be equally effective for all types of cancers.

The study has so far included about 170 patients.

The first 100 people were in the late stages of their cancer when they enrolled, Lim said, and about half appeared to have benefited from the study.

The most recent group of 70 patients, who are all considered terminal but entered at earlier stages of their condition, are mostly still receiving treatment and it's too early to evaluate their progress.

"We really cannot guarantee that based on POG-directed therapy you're going to get a response," he said.

"We've also had some people who've had no response. That's the nature of cancers -- we don't know anything."

For now, Keating knows she's in uncharted territory.

Her health has improved in ways that no one had predicted, and not even her doctors are sure what her future holds.

"Cancer is a very tenacious organism and it finds ways to beat drugs," she said.

"I'm cautious. But as my dear son says, I don't know anything more than what we have right now, so that's what we have."