Probably not the news that was hoped for during breast cancer week, which tries to raise awareness of the need for women to undergo routine screening for breast cancer, but it appears that Mammograms have a high rate of false positive results.
The figures themselves seem even more alarming with more than half of women who receive annual mammograms over a decade, being referred back for further testing because of false positives and a shocking one in twelve being referred for a biopsy.
The study which looked at nearly 170,000 women between 40 and 59 from seven different regions around the United States will be published in Annals of Internal Medicine. The research was led by Group Health Research Institute of Seattle for the Breast Cancer Surveillance Consortium. It included around 4,500 women with invasive breast cancer.
Co-author Karla Kerlikowske, a professor of medicine at the UCSF School of Medicine concurred :
“This study provides accurate estimates of the risk of a false-positive mammography and breast biopsy for women undergoing repeat mammography in community practice, and so provides important information about the potential harms of undergoing regular mammography.”
The study also found that women who begin annual screenings earlier are more likely over their remaining lifetimes to get false positive results. While this may result in simply being called back for a second mammogram, it causes the patient undue stress and worry and exposes them to additional xrays and procedures that were not necessary. While fine-needle aspiration or surgical biopsy are less common, they can lead to unnecessary pain and scarring.
Kerlikowske is the lead researcher in a related study published in the same issue that compares the old photographic x-ray techniques with newer digital. This looked at nearly 330,000 women from 40 to 79 with data collated from Breast Cancer Surveillance Consortium. The false positive rates for both methods appear similar, but digital appears more effective in detecting cancer in younger women, those in their forties who generally have denser breasts that make tumors more difficult to spot. They also saw evidence that the digital method improves detection of estrogen receptor-negative tumors, particularly in women aged 40 to 49 years.
Some doctors also argue that regular screening is unnecessary, with the procedure itself being mechanically aggressive for the breast tissue and despite assurances, the amount of radiation a healthy women will receive directed straight at her breasts over one or two decades of annual screenings has been shown to effect the DNA. Recent research published by PubMed.gov showed DNA double-strand breaks induced by mammographic screening procedures in human mammary epithelial cells.
Dr. Samuel Epstein has been warning people for years about the dangers of mammography, explains:
“The pre-menopausal breast is highly sensitive to radiation, each 1 rad exposure increasing breast cancer risk by about 1 percent, with a cumulative 10 percent increased risk for each breast over a decade’s screening…The high sensitivity of the breast, especially in young women, to radiation-induced cancer was known by 1970. Nevertheless, the establishment then screened some 300,000 women with X-ray dosages so high as to increase breast cancer risk by up to 20 percent in women aged 40 to 50 who were mammogramed annually.”
It would appear as always that there is no replacement for a healthy lifestyle and general body awareness. Undergoing all kinds of medical exams, including mammograms which form a large part of the cancer detection industry, can cause as much harm as good.
As far as false positives are concerned study leader Rebecca Hubbard, PhD, an assistant investigator at Group Health Research Institute concluded :
“We conducted this study to help women know what to expect when they get regular screening mammograms over the course of many years …. We hope that if women know what to expect with screening, they’ll feel less anxiety if or when they are called back for more testing. In the vast majority of cases, this does not mean they have cancer.”
Written by Rupert Shepherd