National breast cancer audit: ductal carcinoma in situ management in Australia and New Zealand

Abstract

Background: Ductal carcinoma in situ (DCIS) is a significant issue in Australia and New Zealand with rising incidence because of the implementation of mammographic screening. Current information on its natural history is unable to accurately predict progression to invasive cancer. In 2003, the National Breast Cancer Centre in Australia published recommendations for DCIS. In Australia and New Zealand, the National Breast Cancer Audit collects information on DCIS cases. This article will examine these recommendations and provide information from the audit on current DCIS management. Methods: Three thousand six hundred and twenty-nine cases of DCIS were entered by 274 breast surgeons between January 1998 and December 2004. Data items in the National Breast Cancer Audit database that were covered in the National Breast Cancer Centre recommendations were reviewed. Information was available on the following: diagnostic biopsy rates for all cases and mammographically positive cases and rates of breast conserving surgery (BCS), clear margins following BCS, postoperative radiotherapy following BCS for groups at high risk of recurrence as well as axillary procedures and tamoxifen prescription. Results: Close adherence was found in diagnostic biopsy, BCS and clear margin rates. Some high-risk groups received radiotherapy, although women with ‘close’ margins did not in 33% of cases. Axillary procedures were conducted in 23% of cases and most (81%) patients were not prescribed tamoxifen. Conclusion: There was predominantly close adherence to recommendations with three possible areas of improvement: fewer axillary procedures, an appraisal of radiotherapy practice following BCS and more investigation into tamoxifen prescription practices for DCIS.