The management of ductal carcinoma in situ (DCIS). The Steering Committee on Clinical Practice Guidelines for the Care and Treatment of Breast Cancer. Canadian Association of Radiation Oncologists.

OBJECTIVE: To help physicians and patients arrive at the most clinically effective approach to the management of ductal carcinoma in situ (DCIS).

OPTIONS: Mastectomy, wide-excision breast-conserving surgery (BCS) plus radiotherapy and BCS alone.

OUTCOMES: Overall survival, local recurrence, cosmesis, complications of therapy.

EVIDENCE: Review of English language literature published between 1976 and December 1996; identified through MEDLINE. Nonsystematic review continued to July 1997. Also reviewed were reference lists of books and relevant articles.

RECOMMENDATIONS: The first step in the diagnosis of DCIS, after history-taking and clinical examination, is a complete mammographic work-up. Once DCIS is suspected, either image-guided core biopsy or open surgical biopsy must be carried out. At surgical excision, the suspect area should be removed in 1 piece and a specimen radiograph obtained. Tissue should not be sent for frozen-section examination or hormone receptor analysis. The pathology report should address those features that bear on treatment choice. The specimen should, whenever possible, be reviewed by a pathologist experienced in breast disease. Treatment options for DCIS are mastectomy, wide-excision BCS plus radiotherapy or BCS alone. Treatment should aim to achieve a high degree of local control with the first treatment plan. Final decisions on treatment should not be made until the pathological findings have been reviewed and the specimen radiograph compared with the mammogram. Mastectomy is indicated when lesions are so large or diffuse that they cannot be completely removed without causing unacceptable cosmesis or when there is persistent involvement of the margins, especially with high-grade malignant lesions. Subcutaneous mastectomy should not be used to treat DCIS. Mastectomy should not be followed by adjuvant local radiotherapy or systemic therapy. Bilateral mastectomy is not normally indicated for patients with unilateral DCIS. BCS requires wide excision in patients with DCIS. It should be followed by mammography of the involved breast if the specimen radiograph does not clearly include all microcalcifications. BCS should normally be followed by radiotherapy. However, omission of radiotherapy may be considered when lesions are small and are low grade, and when pathological assessment shows clear margins. BCS should be accepted by patients only after they have received a careful explanation of the need for radiotherapy, its side effects and the associated logistic requirements. Axillary surgery, whether as a full or limited procedure, should not usually be performed in women with DCIS. Evidence is not available to support the use of tamoxifen in the treatment of women with DCIS. Patients should be offered the opportunity to participate in clinical trials whenever possible.

VALIDATION: Guidelines were reviewed and revised by the Writing Committee, expert primary reviewers, secondary reviewers selected from all regions of Canada and by the Steering Committee. The final document reflects a consensus of all these contributors.