Reflex Estrogen Receptor (ER) and Progesterone Receptor (PR) Analysis of Ductal Carcinoma In Situ (DCIS) in Breast Needle Core Biopsy Specimens: An Unnecessary Exercise That Costs the United States $35 Million/y.

Most institutions reflexively test all breast core needle biopsy specimens showing ductal carcinoma in situ (DCIS) for estrogen receptor (ER) and progesterone receptor (PR). However, 5 factors suggest that this reflex testing unnecessarily increases costs. First, ER/PR results do not currently impact the next step in standard therapy; namely, surgical excision. Second, a subset of surgical excisions performed for DCIS diagnosed on core needle biopsy will harbor infiltrating mammary carcinoma, which will then need to be retested for ER/PR. Third, because ER and PR labeling is often heterogeneous in DCIS, negative results for ER/PR on small core needle biopsy specimens should logically be repeated on surgical excision specimens with larger amounts of DCIS to be sure that the result is truly negative. Fourth, many patients with pure ER/PR-positive DCIS after surgical excision will decline hormone therapy, so any ER/PR testing of their DCIS is unnecessary. Fifth, PR status in DCIS has no proven independent value. We now examine the unnecessary added costs associated with reflex ER/PR testing of DCIS on core needle biopsy specimens due to these factors. We reviewed 58 core needle biopsies showing pure DCIS that also had a resulting surgical excision specimen at our institution over a period of 2 years. No patient received neoadjuvant hormone therapy. On surgical excision, 5 (8.6%) had only benign findings, 44 (75.9%) had pure DCIS, and 9 (15.5%) had DCIS with invasive mammary carcinoma. The 9 cases with invasive mammary carcinoma in the surgical excision specimen (16%) and the 4 pure DCIS in surgical excision specimens that were ER/PR negative on core needle biopsy would need repeat ER/PR testing. The total unnecessary increased cost of core needle biopsy specimen testing of these 13 cases was $8148.92 ($140/patient for the 58 patients in the study). We found that ER/PR testing results impacted patient management in only 16/49 pure DCIS cases after surgical excision (33%), indicating that ER/PR testing costing $20,685.72 ($357/patient in the study) had been performed unnecessarily. PR testing could have been omitted in the 16 cases in which ER/PR results were used, which would have saved $5014.72, or $86.46 per patient. Extrapolating the increased cost of $583 per DCIS diagnosis on core needle biopsy to 60,000 new cases of DCIS in the United States each year, reflex core needle biopsy ER/PR testing unnecessarily increases costs by approximately $35 million. We recommend that ER/PR not be reflexively ordered on core needle biopsy specimens or surgical excision specimens containing DCIS, but instead that ER alone be performed on surgical excision specimens only when hormone therapy is a serious consideration after medical oncology consultation.