TORONTO, CANADA. Several clinical trials have observed a reduction in mortality from breast cancer in women over 50 years of age who received regular mammograms. It is not known, however, whether this benefit is greater than that obtained by an annual physical examination alone. Researchers at the University of Toronto now report the results of a study designed to answer this question. The clinical trial involved 39,405 women aged between 50 and 59 years at time of entry into the study between 1980 and 1985. The women were randomized to receive either an annual mammogram (two-view) and physical examination of the breasts or just physical examination alone. All participants were taught and encouraged to practice self-examination as well.
By December 31, 1993 622 invasive and 71 in situ breast carcinomas had been discovered in the mammography plus physical examination group and 610 invasive and 16 in situ cases had been observed in the physical examination group only. Although the cancers tended to be discovered earlier in the mammography group there was, after 13 years of follow-up, no difference in breast cancer mortality between the two groups (107 deaths in the mammography group and 105 in the physical examination group only).
The biopsy rates were considerably higher in the mammography group. In this group 24.3 per cent of the participants underwent biopsy after the first screen as compared to 8.7 per cent in the physical examination group. The researchers also noted a significant increase in deaths from pancreatic cancer in the mammography group (42 deaths) as compared to the physical examination group (18 deaths). Although this difference is statistically significant it could, according to the researchers, be due to chance.
The researchers conclude that mammography screening does not result in a decrease in the absolute rate
of advanced breast cancer and does not reduce mortality when compared to physical examination only.
They suggest that physicians and their patients (women aged 50-59 years) consider the option of an annual
physical examination carried out by a health professional trained to recognize the signs of early breast
cancer plus regular self-examination as an alternative to annual mammograms. [43 references]