(NaturalNews) A large and comprehensive study which looked at 90,000 Canadian women aged 40 to 59 for 25 years has cast fresh doubts on the usefulness of mammography. It found that mammograms did not lower the death rate from breast cancer. And it didn't reduce the death rate from all causes, either.
The study, which was published in the British Medical Journal, had compared the outcomes of women who either carried out breast examinations on their own, or underwent regular mammograms and breast examinations by trained nurses.
The number of women randomly assigned to each group was roughly the same - close to 45,000. Slightly more women in the mammogram group were diagnosed with breast cancer - 3,250 vs 3,133, but the number of women in each group who eventually died from breast cancer was virtually identical.
To make things worse, there was the issue of over-diagnosis and over-intervention - about one in five of the cancers detected and treated would not have threatened the women's health and did not require treatments like surgery, chemo and radiation. Previous research
The truth is, despite the findings of this study, the present guidelines for mammograms are not likely to change anytime soon, although the American Cancer Society is reviewing this and other studies. According to Dr. Richard C. Wender, its chief of cancer control, combined data from clinical studies has shown that mammograms reduced the death rate from breast cancer by at least 15 percent for women in their 40s and at least 20 percent for those older.
Such research data has led some experts to believe that mammograms help to lower overall breast cancer death rates via early detection. For example, in the 3rd edition of The Definitive Guide to Cancer: An Integrative Approach to Prevention, Treatment, and Healing, the authors state that "mammography has been associated with an overall decreased risk of death due to breast cancer."
However, some limitations of prior research which suggested the usefulness of mammograms in reducing breast cancer death rates have been pointed out. For example, unlike the recent Canadian study, many previous studies did not randomly assign the women to mammogram or no mammogram, which is considered a gold-standard of clinical trials. Further, the women in the recent study were aware of the disease and its dangers, unlike the subjects of previous research which would have been likelier to ignore breast lumps; for this latter group, mammograms could indeed be useful.
Many experts also feel that evidence supporting mammogram's usefulness in lowering death rates is lacking or inconclusive, and that mammograms could in fact be harmful. Rates of false positives are high, and an annual mammogram has been estimated to increase breast cancer risk by between 1 percent to 3 percent.
Indeed, Dr. Peter Juni, a former member of the Swiss Medical Board, said that mammograms were not lowering overall breast cancer death rate but instead elevating over-diagnosis, false positives and unnecessary biopsies. Switzerland is the only country which has suggested that mammogram screening be stopped.
Dr. Mette Kalager, an epidemiologist and screening researcher at the University of Oslo and the Harvard School of Public Health, expressed surprise that mammogram's lack of effectiveness in lowering death rate and over-diagnosis rate were similar to those of prostate-specific antigen (PSA) screening for prostate cancer, considering that most nations support mammograms while most do not encourage PSA screening. Based on available research data, should mammograms not be discouraged, too?
With experts divided, women and their families have to weigh the pros and cons of mammograms and arrive at a personal decision.
Sources for this article include:http://www.nytimes.com