Israeli experts downplay Canadian study on mammography screening

Canadian study presented new doubts about whether the breast x-rays should be used to screen seemingly healthy women.

A monitor shows the image of a woman infected with breast cancer. (photo credit: REUTERS)
A monitor shows the image of a woman infected with breast cancer.
(photo credit: REUTERS)
Israeli and foreign breast cancer experts are advising caution to women up to the age of 59 in forgoing mammograms, following the publication of this week’s prestigious BMJ (British Medical Journal) that presented doubts on whether X rays should be used to screen seemingly healthy women.
The study, written by experts at the University of Toronto, Women’s College Hospital and the Hospital for Sick Children in Toronto included 90,000 women.
The researchers concluded, from their 25-year follow-up research of women who either had regular mammograms and clinical breast exams by trained nurses or had only clinical exams, that the mammograms did not offer any benefit in saving lives.
The authors argued that “too many mammograms” lead to over-diagnosis, “unnecessary” surgery, chemotherapy and radiation, which themselves can cause death.
The study is likely to cause the same confusion among women that resulted from long-term studies over a decade ago, warning menopausal women not to undergo hormone-replacement therapy because of the “increased danger” of breast cancer – more recent research balanced the findings and caused many women to undergo HRT after all.
The recent study dealt with women who had mammograms between the ages of 40 and 59; in the US, but not in Israel or most of Europe.
Mammograms are recommended to women from the age of 40, even though, at that age, their breast tissue is not conducive to accurate views of tumors. In Israel, mammograms are officially recommended to normal-risk women between the ages of 50 and 74 (and from 40 to those with a family history) and are included in the basket of health services, provided by the health funds to their relevant members. In fact, the Health Ministry gives incentives to the health funds to send women aged 50-74 for a biennial mammogram.
Prof. Michael Baum, a surgical oncologist and emeritus professor of surgery at University College London, who is a long-time and vocal critic of mammography screening, told The Jerusalem Post on Thursday that the Canadian study “must ring the death knell of population based screening for breast cancer.”
But Prof. Cliff Hudis, chief of the breast cancer medicine service at the famed Memorial Sloan-Kettering Cancer Center in New York told the Post that “it was one study that was previously reported. Now there’s a longer follow-up. The flaws in the study were previously identified.
It does not change accepted practice – period!” Prof. Eliezer Robinson, chairman of the Israel Cancer Association and a veteran oncologist at Rambam Medical Center, Haifa said that “there is over-diagnosis, but this study throws the baby out with the bath water.”
“It is too premature to change our advice on screening, on the basis of this study. I recommend that the Health Ministry set up a committee of experts in the field to deliberate on the evidence and decide what to recommend to doctors and women – and to continue to recommend and perform mammography screening for women over 50.
“Women should be presented with both sides of the argument so they can consult and decide what to do. I will raise the study at the National Council on Oncology that will meet next week,” said Robinson.
Years ago, self-examinations by women had been recommended, but more recently, this advice was trashed when found that this did not increase survival rates. Instead, mammographies and clinical examinations were recommended, said the ICA chairman.
“The evidence has to be studied very meticulously before guidelines are changed, and this study is not enough. I bet that if 1,000 post-menopausal women [were] told about the study [and] were asked if they wanted to undergo mammograms, they would decide to do it,” he said.
Dr. Lital Keinan, a breast cancer expert at the Health Ministry’s National Center for Disease Control, told the Post that the Canadian study was originally carried out in the 1980s. “The patients were not randomized [and] it is not clear what kind of mammograms the women underwent. Women who were part of clinical studies naturally had more awareness of cancer and could have had different lifestyles that made the long-term results irrelevant.
“We at the ministry know that mammography screenings raise awareness to the potential of breast cancer both among those who are screened and those who are not, but go quickly to their doctors when they suspect something,” Keinan said. “There is no reason to stop screening. There is a delicate balance between screening and over-diagnosis, benefits and harm.”
She said she would continue to undergo mammograms and recommended that an expert committee discuss the findings.
Dr. Shalom Strano, director of the new one-stop multidisciplinary Diagnostic Breast Health Center at Shaare Zedek Medical Center, Jerusalem, said the BMJ study was not truly randomized or double-blinded, as required in authoritative medical research.
“The quality of mammograms in the 1980s was atrocious. Over-diagnosis is much less than people think. The study was poorly designed, there is nothing new,” he said. “We are moving in the direction of being more selective and giving higher-risk women mammograms, but we are not giving them up.”