B.C. doctors turning to DNA to develop personalized cancer treatments

Leslie LaForest has seen her cancerous tumours shrink after beginning a clinical trial of a new treatment called personalized onco-genomics.

Scientists in B.C. are helping to develop a new way of treating cancer by using a patient's DNA to come up with a customized treatment plan.

Fighting cancer has long been considered an educated guessing game, where physicians pick a therapy and hope that it helps eradicate a tumour. But doctors at the BC Cancer Agency are developing new techniques to treat cancer using DNA analysis to pick the best drugs for a patient.

It's called personalized onco-genomics (POG), and for some patients the results have been promising.

For four years, Leslie LaForest was being treated for her anal cancer using a traditional method. But in March, doctors found out that her cancer had spread; one tumour in her body was the size of a golf ball.

"It's desperate," LaForest told CTV News, describing her fears. "Obviously, you immediately go to a dark place and think that you're going to die."

With her life on the line, she joined a landmark clinical trial at the BC Cancer Agency.

Doctors at the agency took a biopsy, looking for any genetic mutations in her cancer cells that aren't in her normal cells. They soon discovered that her cancer had a weakness, and found a drug, still in development, that could interfere with her tumour's growth.

LaForest started taking the pills in early July, and nine weeks later, in September, she learned her tumours are shrinking.

"This lymph node -- which was about the size of a golf ball, or a little larger -- is all down to scar tissue," Dr. Janessa Laskin told her during a recent appointment.

LaForest was ecstatic. "I am grinning from ear to ear," she said. "It has profoundly changed my life."

Laskin said the hope for the patients enrolled in the BC Cancer Agency study is that each will have a personalized treatment plan with fewer side effects.

"All the people in the program do have metastatic or incurable disease. What we hope to do is find more treatments that are going to work better, work for longer, with fewer side effects," she said.

The same approach was used on patient Trish Keating.

Last year, doctors used DNA analysis to determine that her incurable colon cancer could potentially be treated with a common blood pressure drug.

Tests revealed a specific protein was acting as a driving force behind her cancer. She was subsequently put on a blood pressure medication that blocks the protein. Within a few weeks, tests found that her cancer was barely detectable.

Her cancer is still in remission.

"There is nothing detectable," Keating said of the personalized treatment. "It is definitely a miracle."

The scientists heading up the study in B.C. are hoping to share what they're learning with other doctors across the country.

With a report from CTV News' Medical Correspondent Avis Favaro