Mammary ductal carcinoma in situ (
DCIS) is classically treated by combinations of excision, radiation, and endocrine
therapy, based upon the specific needs of individual patients.
Estrogen receptor (ER) status is generally assessed by immunohistochemistry (IHC) in newly diagnosed cases of
DCIS, and endocrine
therapy in this setting is thought to be chemopreventive. The potential impact of
androgens on mammary
carcinogenesis has been studied in recent years, and several authors have proposed
androgen receptor (AR) IHC testing and targeted antiandrogenic
therapy in patients with locally advanced or metastatic triple-negative invasive
breast cancer (ie, negative for ER and
progesterone receptor and HER-2). Very little has been published on AR in
DCIS. We report results of AR IHC on archival tissue blocks from 221 adult female patients, each of whom underwent definitive breast resection of
DCIS. Of the 221 cases, 72 (33%) were shown to express AR in their
DCIS at or above the 10% threshold often used for invasive
carcinoma. AR expression was seen in all grades of
DCIS. Of the 72 positive AR cases, 21 (29%) were ER negative, corresponding to 10% (21/221) of all patients. The majority of the AR-positive cases were high grade, and the most common histologic subtype in this subset was a solid growth pattern with apocrine features. Early data from clinical trials evaluating AR antagonists in invasive/metastatic
triple-negative breast cancer suggest that some patients may benefit from
androgen blockade. IHC testing and potential clinical trials of AR antagonists for
chemoprevention in patients with AR-positive and ER-negative
DCIS could be considered.