VANCOUVER — A leading B.C. breast-cancer expert predicts an increase in cases and deaths if women and doctors pay too much heed to “alarming” recommendations from a Canadian task force.
Radiologist Dr. Paula Gordon doesn’t deny that screening can occasionally lead to false positives, overdiagnosis and overtreatment. But she said certain studies were ignored — including a B.C. one — that show a 25-per-cent reduction in mortality among women screened by mammograms.
The task force also put too much stock on research that was poorly designed or was done decades ago, she contends.
“False positives can indeed cause harm because they can be traumatizing, and I agree that women should consider the potential harm of screening. But it is absurd that the task force is recommending no self-examination by women [without risk or symptoms] and no clinical examination by family doctors,” said Gordon, who was reacting to the task force report as chairwoman of an early detection working group of the Canadian Breast Cancer Foundation (BC/Yukon). She is also medical director of the breast health program at B.C. Women’s Hospital.
“This puts us back to the 1960s because the task force relied on old trials using equipment that is now obsolete. So it’s advising women in their 40s to make decisions based on scientific evidence that is older than they are,” said Gordon, referring to the advice against regular screening for low-risk women aged 40 to 49.
Gordon said mammograms do turn up abnormalities that are not cancerous, but false positives are inevitable and occur in all screening tests, including pap smears for cervical cancer. However, she cited surveys that show even with the risks of false positives, women would still rather have tests or even biopsies done, rather than delay diagnosis and treatment.
As to the task force’s recommendation that women at average risk of breast cancer have no need to routinely examine themselves or seek the same from doctors, “women are effectively being told to wait till they see a lump in their breast in the mirror before they seek treatment.
“ By that time, even with excellent care, mortality rates will return to what they were in the 1970s.”
Task force members, including Simon Fraser University researcher Michel Joffres, said not all breast tumours require treatment because some small ones may spontaneously regress. But Gordon disputed that.
“Nobody has evidence of self-healing and regression,” she said. “When we see cancer, it is not possible to predict how long it will take to grow. Just because we need to get better at knowing these things doesn’t mean it’s okay to stop looking for cancer.”
Joffres said about 12 per cent of women who go for screening are told they have an abnormality, and of those, seven per cent will be told, after further testing, they have cancer. One study showed that five of every 1,000 women aged 39 and older screened through mammography may be overdiagnosed and have unnecessary surgery to remove breasts or portions of them “and that is not an insignificant proportion,” he said.
Joffres and Gordon did agree on one thing: more confusion for women and primary care doctors. Joffres said the task force guidelines are meant to provoke more informed discussion between women and their doctors.
“These are weak recommendations; we’re not saying don’t do it,” he said.
B.C. was the first province in Canada to establish a breast cancer screening program in 1988. Women aged 40 to 79 are offered an X-ray at least every two years. Twenty per cent of cancers occur in women in their 40s, 25 per cent in females in their 50s, 27 per cent in their 60s and 28 per cent of breast cancers occurs in women over 70, Gordon said.
Carol Thorbes, an SFU communications officer who had routine mammograms and was considered an average risk when she was diagnosed with breast cancer at 49, said she’s concerned doctors will be less vigilant as a result of the proposed guidelines.
Her sister in Ontario died of breast cancer at 46 and Thorbes says there are pronounced differences between the provinces, with B.C. doctors far more supportive of routine screening, even in low-risk patients.
Sun Health Issues Reporter