Warming up while stripped down, several runners in Ottawa got their below-the-waist cancers exposed to the public on Saturday by dashing around the federal capital in their underwear.

It was for the annual Underwear Affair, which is held in several cities worldwide. Some runners were in animal print, and others wore nothing but the bare essentials, like Sean Petrie.

He was running for his uncle and grandmother -- both have colon cancer.

"I don't know a better way than 500 people running around in their underwear that people notice them," Petrie said. 

Hitting below the belt

The message: be more aware of cancers that occur below the belt.

Prostate and colorectal cancer are two of the most common cancers in Ontario, affecting parts of the body many aren't comfortable talking about -- let alone checking.

"It's as important to check testicles as it is to check breasts," said Linda Eagen, of the Ottawa Regional Cancer Foundation.

"Even I'm having a hard time saying it: we're not comfortable talking about these things. Young people are especially uncomfortable."

The St. Louis Skivvies

Part of the proceeds from the Underwear Affair run are going to a new program call Check 'Em, that targets young men.

Kelly Patterson's brother Luke Rochefort has testicular cancer -- he is 29. "I know my brother, Luke, wanted to get the message to young guys who don't wanna go to the doctor: get checked."

Rochefort's team -- the St. Louis Skivvies -- has raised $40,000.

"It's good there is a way around it, and we can find a cure and have fun doing that," said Patterson.

Nearly 400 people bared it all, raising more than $200,000. Organizers say it will be back next year, giving these cancers the exposure they need.

With a report from CTV Ottawa's Alyshah Hasham