Screening for breast cancer: significant reduction in mortality

The Quebec program of breast cancer screening (PQDCS) would have reduced the mortality rate of 35% to 41% among women who had at least one mammogram between 1998 and 2003. This emerges from a recent report published by the Institut national de santé publique du Québec (INSPQ), which analyzes trends in mortality from breast cancer since the establishment of PQDCS in 19981. This program is for all Quebecers 50 years to 69 years. In total, 523 830 women took part in the program and have undergone at least one mammogram during the first five years of implementation, or 49.7% of 1 054 620 women who were eligible. It is estimated to have prevented 30 deaths from breast cancer for every 100 000 women who participated in the program during this période2. But when one takes into account all eligible women, ie including those who have not gone mammography, reducing the mortality rate goes down around 7% to 11%. Encouraging results When setting up the Québec breast cancer screening, an estimated 247 women who participated in the program were going to die of breast cancer. But five years later, there were 160 deaths, a difference of 35% compared to forecasts of departure. Report data have also highlighted the importance for women to undergo mammography once they become eligible. For example, among women 50 years to 59 years, an estimated 134 deaths "expected" by breast cancer at the beginning of the program. Five years later, 75 died as a result of this cancer, ie 44% less than was anticipated. Among women aged 60 to 69 years, there have been 85 deaths from breast cancer, while anticipating 113. A difference of 25%. "It's the kind of reductions that were expected," said Dr. Jacques Brisson, co-signatory of the report and expert associated with INSPQ. Also professor of epidemiology at the Faculty of Medicine, Laval University, Dr. Brisson believes these results should encourage more women to take part in PQDCS. Nevertheless, he agrees that the report does INSPQ as a positive element of the program, ie the reduction in mortality. According to him, the choice whether to participate in a screening program based on a balance between the advantages and disadvantages in it. Among these drawbacks, the fear and anxiety arising from a first mammogram positive. "1 For 000 women who undergo screening, 10% to 12% will undergo a subsequent examination and some will have biopsies, he concludes. However, approximately 95% of abnormal mammograms will not lead to a diagnosis of breast cancer. " In Canada, the mortality rate due to breast cancer has been declining since the mid-1980s. It has fallen more than 25% since 1986, from 32 to 23.1 deaths per 100 000 femmes3. It is estimated that one in nine women may have breast cancer during her lifetime and one woman in 28 will die.