[168] Sentinel Lymph Node Biopsy (SLNB) in Ductal Carcinoma In-Situ (DCIS) – A Study of 90 Cases

DA Chitale, SD Nathanson. Henry Ford Hospital, Detroit, MI

Background: Sentinel lymph node biopsy (SLNB) is well established for invasive ductal carcinoma but the role of this procedure in DCIS remains controversial. Most breast cancer management guidelines discourage axillary lymph node staging in pure DCIS when breast conserving surgery (BCS) is performed. SLNB for DCIS is currently limited to patients who undergo mastectomy. We sought to review our experience of SLNB in DCIS, and to determine from our database whether SLNB is appropriate in all patients with DCIS electing mastectomy.
Design: From April 1995 through December 2008, 90 cases of DCIS in whom SLNB were performed. SLNB in DCIS was done if elected or at surgeon's discretion. All the SLNs were step-sectioned and entirely submitted. Immunohistochemistry for cytokeratin was not performed routinely.
Results: 77/90 cases were pure DCIS, 13/90 DCIS with microinvasion (DCISM). 70/90 patients had a mastectomy and SLNB (68-DCIS, 2-DCISM). BCS with SLNB was done in 20/90 (9-DCIS, 11-DCISM) for extensive DCIS. 5/90 (4-DCIS, 1-DCISM) (5.6%) revealed metastatic tumor in the SLN (+SLNB) 4 of which had mastectomy. 3 patients underwent complete axillary lymph node dissection; none had metastasis in non-SLN. 4/5 +SLNB cases had tumor size > 4 cm[4 cm-DCISM, 4.5 cm, 4.6 cm,11.0 cm-DCIS; mean:6.03 cm, standard deviation:3.33] and all high nuclear grade with necrosis. The 5th +SLNB had 1cm DCIS size but had contralateral invasive ductal carcinoma with metastatic SLN. Among 32 cases of DCIS with size > 4.0cm; 4 (12.5%) had +SLNB and 18/32 (56.3%) were high grade.
Conclusions: Metastasis to SLNs occurred in 5.6% of patients with DCIS. The incidence of SLN metastasis increased substantially in those with DCIS > 4 cm; in these patients microinvasion was identified in about 20%. Non-sentinel node metastasis did not occur. Patients who have a mastectomy for a large DCIS should have a SLNB since microinvasion, and therefore potential SLN metastasis, is related to increasing size. If SLNB is not done in these mastectomy patients, and if microinvasion is found on histology, the only surgical option is complete axillary lymphadenectomy.
Category: Breast

Wednesday, March 24, 2010 9:30 AM

Poster Session V # 45, Wednesday Morning

 

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