Randomized trials have shown that breast cancer screening by mammography reduces breast cancer mortality by up to 40% in women aged 50-69 years. These results led 22 countries, including Canada, to established population-based screening programs by 1998.

In this issue of CMAJ, Dr. Fran�oise Bouchard and coworkers report on the 1996 screening results for 7 provincial screening programs. The recall rates after first and subsequent screens were 9.5% and 4.6% respectively and the cancer detection rate per 1000 women was 6.9 and 3.8 respectively. The authors state that analyses of performance indicators for breast cancer screening show that the benefits of screening can be translated from randomized trials into population-based community programs. They recommend organized screening programs increase to allow more comprehensive monitoring in Canada.

In a related commentary Dr. Anthony Miller considers the additional factors required for effective screening programs: validity and acceptability of the screening test, early diagnosis of progressive disease, effective therapy and good compliance of the at-risk population.

Performance of screening mammography in organized programs in Canada in 1996 � D. Paquette et al

Organized breast cancer screening programs in Canada � A.B. Miller (Dr. Miller is with the Division of Clinical Epidemiology, Deutsches Krebsforschungszentrum, Heidelberg, Germany. He can be reached at 416 978-5662