Axillary dissection and ductal carcinoma in situ of the breast: A change in practice

Background: Axillary dissection may be associated with significant morbidit y and, while it is necessary in the treatment of invasive breast cancer, is not indicated for the treatment of pure ductal carcinoma in situ (DCIS), a lthough it is being performed in a significant number of cases. The present study examined the incidence of elective axillary dissection in the treatm ent of DCIS cases detected in a mammographic screening programme over a 4-y ear period, and whether surgeons have changed their practice in this respec t. Methods: BreastScreen Victoria records were examined retrospectively for th e period from January 1995 to December 1998 to identify patients treated fo r DCIS. The incidence and indications for axillary surgery were investigate d. Results: There were 579 cases of DCIS and 93 (16%) had some form of axillar y surgery, which was thought to be inappropriate in 57 (10%), the latter be ing performed by 21 city surgeons and 20 rural surgeons. Before surgery, 36 (63%) cases were diagnosed by core biopsy or excision, and 21 (37%) had im aging and cytology alone for diagnosis. The rate of unnecessary axillary di ssections dropped steadily from 14% in 1995 to 4% in 1998, a significant re duction (P = 0.01). Conclusion: The incidence of axillary dissection for DCIS has dropped signi ficantly over the last 4 years in Victoria, possibly due to increased aware ness through education and guidelines. Surgeons are now more aware that in situ lesions do not need axillary dissection, and that axillary dissection should not be performed for breast cancer unless invasion has been proved h istologically.