Thousands of Canadian women have responded to the call to "get mad" over new guidelines on screening for breast cancer.

An on-line petition has garnered thousands of signatures in just a few days, calling on Canada's Health Minister to scrap the guidelines.

Breast imaging specialists across this country have urged women to get involved and push to see these guidelines scrapped.

But the task force responsible for the guidelines says the recommendations actually put women in the driver's seat, allowing them to choose whether to screen or not.

51-year-old Elizabeth Barnes has her support system in place as she heads in to the Ottawa Cancer Centre for yet another round of radiation. She was diagnosed with breast cancer last June.

“My cancer is a type that didn't show up at all,” she says, “it was an invisible cancer so I’m lucky it was caught on a mammogram.”

A routine screening caught the mass and she pushed for a biopsy to confirm the cancer.  She's worried women under 50, women with dense breast tissue like hers won't be so "lucky."

“All of this has happened in middle of these recommendations coming out,” she says, “so I do feel a personal connection to these recommendations.  I feel I have something to say about those.”

Those recommendations, released last month by the Canadian Task Force on Preventive Health Care don't recommend routine screening for women under 50, don't take into account dense breasts and don't recommend breast self-exams, prompting more than 150 breast imaging specialists to demand the federal government reject the guidelines.

“These guidelines, if adopted,” said Dr. Jean Seely, a breast imaging specialist at The Ottawa Hospital, “will result in 400 lives lost every year to breast cancer.”

“I'm not understanding where those numbers are coming from,” says Dr. Ainsley Moore, the co-chair of the Task Force on Preventive Health Care.

Dr. Moore says these guidelines actually put women in the driver's seat and let them decide whether to screen or not.

“It's personal choice,” she said in a telephone interview, “that should guide women whether to be screened or not. It's a personal call because the margins are so close.”

Then there's the issue of false positives and over-diagnosis.

“The numbers aren't small,” says Dr. Moore, “If you look at one thousand women screened, about 300 between ages of 40 to 59 will have a false positive rate. That’s 30% that will end up with requiring more testing or biopsies. I think the issue of harms is being lost in some of the discussions. They’re not intuitive concepts.  You're thinking that screening is a good thing but there are real harms associated with screening and they haven't been clarified I think.”

Rebecca Hollingsworth isn't buying that.  Both she and her sister were diagnosed with breast cancer in their early 40's.  She started a petition to get Canadians to demand the government drop these guidelines.  Nearly 5000 people have signed it in a matter of days.

“A lot of this doesn't make sense,” she says, “I think some of it is dangerous and I do believe they will cost women, and some men, their lives.”

The Task Force stresses that these guidelines are just that; women can choose to follow them or not.  But the doctors fighting this say that provincial screening programs use these guidelines as "default,” they'll be put into practice.