[157] Sentinel Lymph Node Status among Patients with Pure Ductal Intraepithelial Neoplasia/Ductal Carcinoma In Situ Treated by Mastectomy

Christopher Flynn, Donald R Lannin, Fattaneh A Tavassoli. Yale University School of Medicine, New Haven, CT; Yale New Haven Hospital, New Haven, CT

Background: Ductal intraepithelial neoplasia (DIN)/Ductal Carcinoma in Situ (DCIS) is a non-invasive process limited to the ducts and lobules of the breast. Nonetheless, as many as 9% of DIN/DCIS cases have been reported to have lymph node (LN) involvement by “metastatic carcinoma.” Among the previously reported series, however, were cases suspicious for microinvasion. A large number of the reported cases were also treated by lumpectomy and consequently an occult infiltrating carcinoma may have gone undiagnosed. Confounding the issue, patients regularly have at least one if not multiple biopsies and/or aspirations before the final excision. To determine the frequency of LN involvement in cases of DIN/DCIS and the contribution of previous instrumentation, we evaluated all pure DIN/DCIS lesions treated by total mastectomy and sentinel lymph node (SLN) evauation.
Design: At our institution, SLN assessment is routinely performed on all DIN/DCIS lesions treated by mastectomy. A total of 252 mastectomies with DIN/DCIS and a SLN evaluation from 2002-2012 were retrieved. All clinical and pathological data were reviewed. The clinicopathological features of the cases with any LN involvement were compared to those without LN involvement to determine if there was a correlation between any lesional or clinical characteristics (i.e. size or type of DIN/DCIS, number of procedures prior to mastectomy/sentinel lymph node biopsy, etc.) and the nodal status.
Results: Of the 252 cases evaluated, 9 (3.6%) had tumor cells in the SLN. All nine (100.0%) of these were isolated tumor cells (ITC) identified by immunohistochemistry only. Overall, the 9 patients with nodal involvement had, on average, 3.7 samplings prior to the mastectomy compared to 2.1 among those patients with no nodal involvement.
Conclusions: The frequency of LN involvement in DIN/DCIS has been reported to be as high as 9%. The 3.6% in our study is substantially lower. This may reflect the more stringent criteria used in our study with the exclusion of any case with micro-invasion and the limitation of our cases to mastectomy specimens. Given this low frequency and the fact that only ITC were found in the involved LNs, it would be reasonable to hypothesize that these patients are at no higher risk for subsequent metastasis or recurrence than patients with DIN/DCIS and no nodal involvement. Also, the presence of neoplastic cells in the LN may well be secondary to prior sampling manipulations.
Category: Breast

Tuesday, March 5, 2013 9:30 AM

Poster Session III # 27, Tuesday Morning


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