Most healthy Canadian women under 50 don't need regular mammograms, and even those over 50 can safely go as long as every three years between scans, advise new breast cancer screening guidelines.

The guidelines come from the Canadian Task Force on Preventive Health Care (CTFPHC), a group of physicians who say they have combed the latest science before issuing these latest recommendations, which are sure to reignite the debate about the best way of spotting breast cancer early.

The new guidelines apply to healthy women who have never had breast cancer, don't have a first-degree relative (such as a mother or sister) with a history of the disease, and no known genetic risks. For these women:

• No routine mammograms are needed in women aged 40 to 49
• Wwomen aged 50 to 74 can cut back on the frequency of screening mammograms from every 2 years to "every 2 to 3 years"
• Women age 70 to 74 should also have mammograms every two to three years
• No recommendations for women aged 75 years and older, because of a lack of data on this age group
• There is no need for regular breast self-examination
• There is no need for routine clinical breast examinations, either alone or in conjunction with screening mammograms

The guidelines, which appear in the Canadian Medical Association Journal, are the first in Canada in 10 years and are aimed at doctors and the millions of women who have not had breast cancer and don't have a close family member with a history of the disease.

According to the guidelines' authors, the current recommendation that older women go for mammogram tests every two years and undergo regular breast exams is not leading to fewer breast cancer deaths.

What it is doing is spotting a lot of lumps that are not cancer, leading to needless anxiety for these women, as well as unnecessary and painful tests and surgery.

Dr. Marcello Tonelli, the chair of the task force, who's not an oncologist, says there is still a perception that regular and frequent cancer screening saves lives.

"It is only natural to think that detecting a cancer early is going to be beneficial but just like any medical test procedure, screening for breast cancer has potential harms," he told CTV News ahead of the report's release.

The authors note that false–positive results on breast cancer screens can have "a significant impact on the emotional well-being of patients and families."

"They can cause lifestyle disruptions and result in costs to both patients and the health care system," they note.

The guidelines are expected to be controversial. Two years ago, when the United States Preventative Task Force (USPTF) recommended that women at average risk for breast cancer could wait until 50 to start being screened for the disease, rather than 40, they were greeted with a huge backlash and accusations that the government didn't care about the health of women.

These Canadian guidelines are sure to raise eyebrows as well -- especially the recommendation that doctors don't need to perform routine clinical breast exams on their patients.

"I think that this is one recommendation that may in fact surprise people," task force member and family physician Dr. Elizabeth Shaw tells CTV.

"However, we have confidence that the guidelines are based on the latest and best scientific recommendation."

Shaw notes that before these guidelines, there was no recommendation either way on the need for clinical breast exam. When they looked at the evidence, including the report from the USPTF, they found there wasn't enough scientific evidence that the practice saves lives.

‘The current recommendation is based on the fact that the task force could not find any evidence that clinical breast examinations reduced deaths from breast cancer," Shaw said.

The Canadian Task Force on Preventive Health Care is an independent body of experts who are asked to develop clinical practice guidelines that support family doctors and other primary care providers in delivering preventive health care.

The authors of this report point out that their recommendations are meant to act as a guide only and that physicians and patients are free to choose other courses.

"Every woman is different and every woman will need to have a conversation with her primary care physician about the best way to screen for breast cancer," Dr. Shaw says.

"The real hope is that these allow primary care practitioners to have informed conversations with women about the potential harms and benefits of breast cancer screening to allow them to make the best choice for them based on their own personal values and preferences."

CTV medical expert Dr. Marla Shapiro, who was diagnosed with breast cancer in her 40s, points out that the guidelines are setting a bar for the minimum standard of screening; any patient can discuss with her doctor about doing screening more often, if they decide that the risk of getting a false-positive is tolerable.

"The bottom line is that it does not replace a conversation between a physician and a patient on how to assess risk, and also that tolerability between a false-positive and getting a clean bill of health or a mammogram result that suggests you need to do more (testing)," Shapiro told CTV News.

She adds that the guidelines are certainly not saying that women and doctors should never do a breast exam again.

"I don't think there's a physician I know who's going to stop doing breast examination in their office – I certainly won't, nor should we take away the idea that women should NOT do breast exam… What the guidelines are saying is we should not spend a lot of time and resources teaching all women how to do exams every single month," she explained.

She added that women are the ones who know their breasts well. So a woman can still do exams periodically and if she notices something different with her breasts -- a lump or something that's changing – she should go see her physician.

One in nine Canadian women is expected to develop breast cancer in her lifetime; one in 29 is expected to die from the disease.

With a report from CTV's medical specialist Avis Favaro and producer Elizabeth St. Philip