[221] Cytokeratin 5/6 Negative Atypical Ductal Hyperplasia Predicts Disease Progression in Subsequent Breast Biopsies

John C Nguyen, Farnaz Hasteh, Grace Y Lin, Noel Weidner. The University of California San Diego, San Diego, CA; Clarient, Inc., Aliso Viejo, CA

Background: Management of atypical duct hyperplasia (ADH) of the breast remains problematic. Cytokeratin 5/6 (CK 5/6) is expressed in benign intraductal lesions, but absent in ADH, ductal carcinoma in situ (DCIS), and invasive carcinoma. Thus, absence of CK 5/6 immunoreactivity in ADH found in core biopsies may predict disease progression within follow-up specimens.
Design: To study this hypothesis, we examined one hundred and five (105) consecutive breast core biopsies with ADH. CK 5/6 immunostaining was performed and correlated with follow-up findings.
Results: Of the 105 core biopsies, twenty (20) showed positive CK 5/6 staining within the ADH and seventy-six (76) showed negative CK 5/6 staining. The remainder had the ADH exhausted upon recuts.
Of the twenty cases with CK 5/6 positive ADH, thirteen had a subsequent follow-up breast biopsy or excision. None showed disease progression, that is, none had DCIS or invasive carcinoma. More specifically, nine (69%) had no evidence of ADH, DCIS, or invasive carcinoma. However, four (31%) had persistence of ADH.
Of the seventy-six cases with CK 5/6 negative ADH, sixty-four (64) had a subsequent follow-up breast specimen. Nineteen (30%) had no evidence of ADH, DCIS, or invasive carcinoma. Twenty-one (33%) had persistent ADH, nineteen (30%) had progression to DCIS, and five (8%) had progression to invasive carcinoma.
Conclusions: We demonstrate that CK 5/6 expression is useful in predicting disease progression in a subsequent breast biopsy or excision. A majority (69%) that showed positive CK 5/6 staining of ADH did not have evidence of ADH, DCIS, or invasive malignancy in subsequent specimens. However, when CK 5/6 was negative within ADH, the subsequent specimens showed either persistent ADH or disease progress in 70%. Moreover, of the latter group thirty-eight (38%) of the subsequent specimens showed disease progression to DCIS or invasive carcinoma. Thus, there is utility of determining CK 5/6 status of the ADH in core breast biopsies. If the ADH is CK 5/6 positive, close clinical follow-up may be adequate, instead of immediate surgical management. In contrast, patients with CK 5/6 negative ADH would likely benefit from immediate excisonal surgery.
Category: Breast

Wednesday, March 21, 2012 9:30 AM

Poster Session V # 28, Wednesday Morning

 

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