Another new study, this by Danish breast cancer researchers, compared mortality rates in areas with screening programs and those without screening programs in which post-menopausal women undergo routine mammography to help detect tumors have virtually no impact on reducing breast cancer deaths.
Published in the British Medical Journal, the study says that while breast cancer mortality has fallen sharply over the years, there is no evidence this is due to systematic screening. The gains are likely due to better treatment and heightened awareness among women about breast health.
Dr. Karsten Jorgensen, a medical researcher at the Nordic Cochrane Center and lead author of the paper, said that "Public institutions and large patient advocacy groups have been unwilling to admit that there are serious problems. They have tried to paint a rosy picture against mounting evidence of much small benefits than was orginially promised and very serious harms.
The study included data on all Danish women recorded in the Cause of Death Register and Statistics Denmark database between 1971 and 2006. It included 17 years in which there was universal breast cancer screening programs for women aged 55 to 74 in two areas, Copenhagen and Funen County because in the rest of the country there is no organized screening.
Nonetheless, the research team analyzed and compared data from the regions with screening and those without and found:
In the 55-to-74 age group, breast cancer mortality declined by 1 per cent annually in areas with screening and 2 per cent a year in areas where there was no screening.
In the 35-to-54 age group, where screening is not recommended, breast cancer mortality fell 5 per cent a year in areas with screening and 6 per cent in those without.
In the 75-and-over age group, there was no change in mortality in any area.
Breast-cancer mortality dropped steadily in the 10 years prior to screening beginning.
The decision to undergo mammography is a very personal one, which entails both benefits (early detection and treatment of cancer, the peace of mind that comes from receiving a clean bill of health) and risks (the effects of radiation or false positives).
http://www.bmj.com/cgi/content/full/340/mar23_1/c1241