NCCN VERSION 2 2015

NCCN Guidelines Version 2.2015 Breast Cancer

NCCN Guidelines Index Breast Cancer Table of Contents Discussion

HER2 status of DCIS does not alter the management strategy and routinely should not be determined. MRI has been prospectively shown to have a sensitivity of up to 98% for high-grade DCIS. 44 In a prospective, observational study, 193 women with pure DCIS underwent both mammography and MRI imaging preoperatively; 93 (56%) women were diagnosed by mammography and 153 (92%) were diagnosed by MRI ( P < .0001). Of the 89 women with high-grade DCIS, 43 (48%) who were not diagnosed by mammography were diagnosed by MRI alone. Another study evaluated the role of MRI in determining appropriate candidacy for partial breast irradiation for women with DCIS. Twenty percent of women with DCIS were identified as ineligible for partial breast irradiation after a bilateral breast MRI. 45 However, large prospective clinical trials will be necessary to further investigate the clinical role of MRI for diagnosing DCIS and to investigate its effect on recurrence rates or mortality. The NCCN Panel has included breast MRI as optional during the initial workup of DCIS, noting that the use MRI has not been shown to increase likelihood of negative margins or decrease conversion to mastectomy with DCIS. Primary Treatment Seemingly pure DCIS on core needle biopsy will be found to be associated with an invasive cancer on surgical excision in about 25% of patients. 46 For the vast majority of patients with limited disease where negative margins are achieved with the initial excision or with re-excision, lumpectomy or total mastectomy are appropriate treatment options. Although mastectomy provides maximum local control, the long-term, cause-specific survival with mastectomy appears to be equivalent to that with excision and whole breast irradiation. 47-49

Patients with DCIS and evidence of widespread disease (ie, disease in two or more quadrants) on mammography or other imaging, physical examination, or biopsy require a total mastectomy without lymph node dissection. Prospective randomized trials have shown that the addition of whole breast irradiation to a margin-free excision of pure DCIS decreases the rate of in-breast disease recurrence, but does not affect survival 47,48,50-54 or distant metastasis-free survival. 55 Whole breast irradiation after breast-conserving surgery reduces the relative risk of a local failure by approximately one half. If whole breast radiation is used, the use of a radiation boost (by photons, brachytherapy, or electron beam) to the tumor bed is recommended to maximize local control, especially in patients 50 years of age or younger. There is retrospective evidence suggesting that selected patients have a low risk of in-breast recurrence with excision alone without breast irradiation. 56-59 For example, in a retrospective review, 10-year disease-free survival (DFS) rates of 186 patients with DCIS treated with lumpectomy alone were 94% for patients with low-risk DCIS and 83% for patients with both intermediate- and high-risk DCIS. 56 In another retrospective study of 215 patients with DCIS treated with lumpectomy without radiation therapy, endocrine therapy, or chemotherapy, the recurrence rate over 8 years was 0%, 21.5%, and 32.1% in patients with low-, intermediate- or high-risk DCIS, respectively. 57 A multi-institutional, nonrandomized, prospective study of selected patients with low-risk DCIS treated without radiation has also provided some support for the use of excision without radiation in the treatment of DCIS. 60 At a median follow-up of 6.2 years, the 5-year risk of ipsilateral breast recurrence was 6.1% (95% confidence interval [CI], 4.1%–8.2%) in the subset of patients with low-/intermediate-grade DCIS and median tumor size of 6 mm. Margin widths were ≥5 mm in 69.2%

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