PRESIDENT'S CANCER PANEL WILL REVIEW MAMMOGRAPHY DATA

Executive Summary

PRESIDENT'S CANCER PANEL WILL REVIEW MAMMOGRAPHY DATA indicating no benefit from mammography screening in women under 50 after a report on the new data is presented to the panel on March 18. The report, which will be reviewed by the panel's special commission on breast cancer, will provide summary data from a study that concludes that mammography should not be offered as a screening option to younger women. The study was presented at a Feb. 24-25 National Cancer Institute international workshop on breast cancer screening and also is published in the Feb. 25 Online Journal of Current Clinical Trials. There is "no scientific justification for claiming a benefit of breast cancer screening in younger women in terms of mortality," J. M. Elwood, MD, University of Otago, New Zealand, et al., assert in their paper. The authors base their findings on a meta-analysis of the data on mammography screening currently available worldwide. Six large-scale randomized trials of women aged 40-74 that were conducted in the U.S., Canada, Scotland and Sweden were analyzed for breast cancer death rates for each year of followup. After seven years of followup in younger women, the overall ratio of the mortality rate in the screened to the unscreened controls was .99, with a ratio of one meaning no difference in mortality. This result "indicate[s] virtually identical breast cancer death rates" between the intervention and control groups, Elwood, et al. state. Results of the study confirm seven-year followup data from the Canadian National Breast Screening Study (NBSS), which shows no benefit from routine mammograms in women aged 40-49. Preliminary data from the NBSS trial were reported in April 1992 and final seven-year data followed in November. NCI currently recommends that beginning at age 40, women should have a mammogram every one to two years, with annual mammograms beginning at age 50. After reviewing the screening recommendations of individuals, professional groups and national policies, Elwood, et al. found that "clearly...there is no consistency" in recommendations regarding screening in younger women. In general, they say, groups that have applied "objective criteria to the assessment of evidence" support mammography in women over 50 but not in younger women." Workshop Chairwoman Suzanne Fletcher, MD, American College of Physicians, summarized the two-day discussion by emphasizing that a "protective effect" of mammography screening is found in older women (those over 50 years of age) in all of the trials discussed. Areas worthy of further research, according to Fletcher, include the effect of menopause on breast cancer screening; screening in women over 75; and cost effectiveness of various screening modalities. In addition, the 10-year age groupings of patients are "arbitrary" and should be reorganized, she said.