Authors' objectives:

This report presents a population-based cohort study of the rates of use of surveillance mammography, and the rates of subsequent breast surgery following surveillance mammography.

Authors' results and conclusions: Although practice guidelines have recommended annual surveillance mammography, we found that the median interval between consecutive surveillance mammograms is more than one year (14.7 months). We found that women diagnosed at age 70 or older, and women treated by lumpectomy without radiation therapy (RT) were less likely to use surveillance mammography compared to other women treated for breast cancer. The data show long intervals between the date of surveillance mammography and the dates of breast biopsies (median 2.97 months), lumpectomies (median 2.55 months) and mastectomies (median 2.50 months). The reasons for the delay cannot be explained from the data. It is unknown whether the delay is harmful or not. The data also show two-thirds of subsequent breast surgery performed for women previously treated for breast cancer occur more than four months following surveillance mammography. The reason for this finding is not clear, but suggests a hypothesis that surveillance mammography does not detect all recurrences in the breast, or all new primary contralateral breast cancers. If this hypothesis is true, the effectiveness of surveillance mammography might be less than desired. The data also suggest a hypothesis that the women at highest risk for subsequent breast surgery are least likely to use surveillance mammography. The data show that the risk of subsequent breast surgery is highest for women diagnosed at age 70 or older, and for women who were treated by lumpectomy without RT. This is ironic, because these are the women who are least likely to undergo surveillance mammography.

Authors' recommendations: The following indicators should be monitored: (1) The rates of use of surveillance mammography among the women at highest risk for recurrence of cancer in the breast or for contralateral new primary breast cancer should be monitored, because these are the women who might benefit the most from surveillance mammography but they are least likely to receive it. (2) The interval between surveillance mammography and subsequent breast surgery should be monitored, because delay between surveillance mammography and surgery may be inappropriate. (3) The number of women who undergo subsequent lumpectomy or mastectomy, which is apparently precipitated by surveillance mammography within the preceding four months, should be monitored and compared to the number who undergo surgery without surveillance mammography during the previous four months, because this may reflect the relative effectiveness of surveillance mammography.

Authors' methods: Cohort study

Project Status: Completed

URL for project: https://www.ccohta.ca/

Year Published: 2001

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: Canada

Organisation Name: Canadian Coordinating Office for Health Technology Assessment

Contact Address: 600-865 Carling Avenue, Ottawa, ON K1S 5S8 Canada. Tel: +1 613 226 2553, Fax: +1 613 226 5392;

Contact Name: requests@cadth.ca

Contact Email: requests@cadth.ca

Copyright: Canadian Coordinating Office for Health Technology Assessment