A new study in the field of breast cancer prevention and cure has revealed startling results, kicking up a controversy amidst the international medical fraternity. The study, conducted by Canadian researchers, has questioned the deep-seated belief that regular mammograms aided in the decrease of deaths due to breast cancer. It has also suggested that yearly mammograms may be creating an upsurge in the number of women unreasonably getting cured for breast cancer. The air in the medical community is now fraught with tension over the study, which has overtly stated that breast cancer death rates are not decreased by mammograms.
The study, which is one of the biggest and most diligently conducted assessment of mammography, tracked almost 90,000 women, aged 40 to 59, for a quarter-century before raising these powerful doubts. It has shown through its observations that fatality rates from breast cancer and from all other causes were the same among women who got a mammogram test every year. More alarmingly, the study claimed that the screening had harmful effects: One in every five cases of breast cancer detected through mammography and treated, was actually not a real threat to the woman’s life and did not need advanced treatments such as surgery, radiation or chemotherapy.
Published on Feb. 11 in the British Medical Journal (BMJ), the study is a pioneer work conducted in the modern era of more successful treatments for breast cancer. In the study, randomly picked Canadian women were assigned to have periodical mammograms and breast examinations done by trained nurses, or to get breast exams alone. The results of the study claimed that 22 percent of aggressive breast cancers were overanalyzed: In other words, these tumors would have usually been too minor to pose a life threat.
When the research tried to ascertain if there was any real advantage to detecting breast cancers when they were too small to feel, they discovered that the answer was a no. The study is likely to polarize opinion on the issue, with many breast cancer patients and mammography advocates believing in its life-saving capacities, while there is a growing community of researchers who find the evidence unconvincing and unclear.
Doctor Russell P. Haris who is a screening expert and a professor at the University of North Carolina, Chapel Hill felt that the study would and should make women uncomfortable. Dr. Russel, who was not part of the study also felt that the decision to get a mammogram should not be made mindlessly.
While these findings may not lead to any immediate changes in mammography guidelines, they have definitely ignited several spirited disputations of the suggestion that mammograms may be useless and even dangerous. Reacting to the study, the American Cancer Society has convened an expert panel to review all researches on mammography, including the Canadian study, which has suggested that breast cancer deaths are not decreasing with yearly mammograms.
Dr. Richard C. Wender, the chief of cancer control for the Society said that revised guidelines would be introduced later in 2014. He also said that the combined data from mammography clinical trials showed at least a 15 percent reduction in death rate from breast cancer, for women in their forties and a minimum 20 percent reduction for older women. In short, one in 1000 women who start their screenings at their 40s and two in women who start at their 50s and three in women who begin at their 60s will escape death by breast cancer.
An editorial that accompanied the new study opined that studies conducted earlier found mammograms helpful possibly because they were done before drugs like tamoxifen (which drastically reduced the breast cancer fatality rate) became routine prescriptions. Written by Dr. Mette Kalager from the University of Oslo and the Harvard School of Public Health in collaboration with other experts, the editorial also delved into the gold-standard methods of clinical trials. Dr. Kalager, who is an epidemiologist and screening researcher at both institutions, felt that a number of earlier studies did not adhere to the gold-standard of randomly assigning which women were to be screened in clinical trials.
The difference in the results of the Canadian study and those of earlier studies was probably because with better treatments like tamoxifen, the urgency to detect cancers earlier has gone down, according to Dr. Kalager. She also added that the mammography screening might work if the women didn’t have any awareness of the disease, which was not the case in the Canadian study.
Though the benefits of mammography have been debated for long, Switzerland is the only nation in the world to halt screenings. Recently the expert panel of the Swiss Medical Board, established by regional public health ministers, released an advisory that no new mammography programs be begun. Those already in existence have been given a limited, but unspecified duration. According to Dr. Peter Juni, who was a member of the board until recently, one of the primary reasons for the move was that screenings were not diminishing the overall rate of breast cancer deaths. They were instead increasing over-diagnosis that lead to false alarms and unnecessary biopsies.
Every year an approximate 37 million mammogram screenings are done in the United States, with each costing about $100. Almost three-quarters of women between ages 40 and above have had a mammogram in the last one year. In several European countries, over 90 percent of women aged 50 to 69 have had at least one mammogram performed. Going by these statistics, the Canadian study’s findings that mammograms may not be decreasing deaths caused by breast cancer could be unsettling for scores of women around the world.
By Aruna Iyer