Known as "Iron Mike" for his tough coaching style, Mike Keenan isn't one to back down from a challenge. He won 672 games during his NHL career (placing him in the top 10 for career coaching wins of all time), and he led the New York Rangers to their first Stanley Cup in 1994.

Yet Iron Mike faced his most difficult challenge to date when he was diagnosed with prostate cancer in May 2018.

Despite consulting some of the top hospitals in the U.S., Mike chose to be treated at Sunnybrook. The Bowmanville, Ont. native was impressed by Sunnybrook's reputation as a leader in brachytherapy, a minimally invasive treatment with a high chance of cure and low risk of serious side effects.

"I had a choice, and that's the choice I made," Mike says. "Sunnybrook is the leading hospital and does the most brachytherapy procedures of anyone else."

Indeed, Sunnybrook's Odette Cancer Centre performs the largest volume of brachytherapy cases annually in North America, and the largest volume of prostate brachytherapy cases in the world.

Prostate brachytherapy involves inserting tiny radioactive seeds into the prostate. These seeds slowly give off radiation over two years. The radiation dose is deposited almost exclusively within the prostate, which can kill off cancer cells with little risk of damaging surrounding tissue.

Mike's brachytherapy treatment was performed by radiation oncologist Dr. Hans Chung in September 2018.

The one-day procedure was a success.

After taking it easy for several months to recover, Mike was given the go-ahead by his medical team to return to his normal activities, which include spending time with his grandchildren.

"Things are aces," he says. "The doctors said, 'You're good to go, do whatever you want,' so back on the horse and away we go."

In addition to feeling grateful for the excellent medical care he received, Mike's experience at Sunnybrook has given new significance to his long-time nickname. Since the radiation seeds stay implanted for life, "I am now the real Iron Mike."