Ductal Carcinoma in Situ Treatment Requires a Multidisciplinary Approach

Correct diagnosis and treatment are crucial for DCIS because it is a direct precursor of potentially lethal invasive breast cancer (IBC). As a result of mammographic screening, the incidence of DCIS rose from 1.87% per 100,000 women from 1973-1975 to 32.5% per 100,000 in 2005. The incidence of DCIS is strongly associated with advanced age, an older age at the time of the first birth or nulliparity, family history of a first-degree relative with BC, BRCA1 and BRCA2 mutation carriers, history of biopsy, late age at menopause, and elevated body mass index, the use of HRT over 5 years. With the use of screening mammography, eight population-based trials showed an increase in DCIS incidence reaching 20% with significant reductions in breast cancer mortality. MRI is also used in combination with the mammography for the diagnosis of DCIS. Three grades of DCIS are ultimately recognized: grade 1/low grade, grade 2/intermediate grade, and grade 3/high grade. Several options are available for the management of DCIS, including breast-conserving surgery, with or without postoperative radiotherapy, and with the clear margin being the most important factor for reducing risk of local recurrence. A 2 mm margin is superior to <2 mm, but there was no significant difference in relapse rate in those with margins of 2 or 5 mm when combined with radiotherapy. The use of mastectomy for treatment of DCIS has declined steadily. Sentinel lymph node biopsy (SLNB) should be performed on patients undergoing mastectomy for DCIS, and a case-by-case decision should be made to perform SLNB in patients who have a high risk DCIS or large tumours. Prospective and retrospective studies have demonstrated excellent long-term results after BCS and radiotherapy, as opposed to BCS alone that has shown a higher rate of local recurrence. Tamoxifen also reduces ipsilateral and contralateral breast cancer events in women with DCIS and is the only systemic therapy approved by Food Drug Administration for this disease. Aromatase inhibitors and other targeted therapies are currently being evaluated in ongoing studies.