[163] Comprehensive Sentinel Lymph Node Examination in Ductal-Carcinoma-In-Situ of the Breast: Much Ado about Nothing

G Falconieri, S Pizzolitto, G DeMaglio. General University Hospital, Udine, Italy

Background: Sentinel lymph node (SLN) biopsy has gained acceptance as a less morbid alternative in breast cancer management. However, its usefulness in ductal-carcinoma-in-situ (DCIS) is controversial, usually being performed under particular clinical conditions when an invasive component is suspected. In addition, the extent of examination and whether it should routinely include multilevel sectioning and cytokeratin immunostaining (CKI) to detect low-volume metastatic disease is still debated. We present our experience with an extended protocol applied to SLN in patients with mammary DCIS.
Design: A total of 65 DCIS of the breast were accessioned between November 1, 2002, and March 31, 2008. Patients' ages ranged from 43 to 80 years. Average age was 56.9 years; 24 patients (36.7%) were premenopausal. Primary tumors were assessed on core needle biopsy (43 cases) and/or a quadrant biopsy (43 cases). Radical mastectomy was necessary in 28 patients. Formalin-fixed SLNs were usually bisected along the longest axis and 2.0-mm thick slices were submitted in separate tissue cassettes. Each SLN block was step-sectioned at 50-m (first 15 levels) and then 100-m intervals (level 16 and over, until block exhaustion), with one section for hematoxylin and eosin (H&E) and one for cytokeratin immunostaining (CKI) using antibody MNF-116. Sections were sequentially numbered in the order they were cut. Immunoperoxidase was ordered in all H&E-negative cases.
Results: In 6 cases (9.2%), microscopic examination of SLNs showed abnormal findings including micrometastases (2 cases) or isolated tumor cells (4 cases). Microscopic findings could be recognized only by means of CKI and were unrecognized on first examination of H&E-stained slides. Axillary dissection was completed in 2 patients with low-volume micrometastases and was negative. No correlation could be observed between SLN results and clinicopathologic parameters, including patient's age, size and extension of DCIS, mammographic features, tumor grade, and estrogen and progesterone receptor status.
Conclusions: Although it may slightly increase the yield of abnormal features, an extended SLN examination protocol is a cost-ineffective and redundant procedure in DCIS, since the gained information is irrelevant to patient care. Whether or not SLN may represent a useful adjunct in selected cases of DCIS, the use of near-total examination methods should be discouraged in routine practice.
Category: Breast

Tuesday, March 10, 2009 9:30 AM

Poster Session III # 64, Tuesday Morning