Can tumor-associated macrophages in ductal carcinoma in situ on biopsy predict invasive carcinoma on excision?

Recent trials have explored surveillance of ductal carcinoma in situ (DCIS) without complete excision, but it is difficult to fully exclude an associated, unsampled invasive focus. Tumor microenvironment, including tumor-associated macrophages, may play a role in the transition from in situ to invasive carcinoma, and the presence of CD163-positive cells with DCIS has been associated with increased risk of progression to invasive carcinoma. We aimed to evaluate the role of DCIS-associated CD163-positive cells on biopsy in predicting associated invasion on excision. Immunohistochemistry for CD163 was performed on 57 total biopsy cases of DCIS of low (n=13), intermediate (n=21), and high (n=23) nuclear grade, 27 (47%) of which showed invasion on the subsequent excision specimen. Positive intratumoral and stromal cells were quantified independently by 2 observers based on the percentage of cells staining. Intratumoral CD163 scores ranged from 0 to 2 (mean, 0.7). Stromal CD163 scores ranged from 0 to 3 (mean, 1.3). lntratumoral and stromal CD163 levels were not significantly associated with the presence of subsequent invasion when evaluated as a whole group (P=.36 and P=.47) or when subdivided into low (P=.36 and P=.17), intermediate (P=.82 and P=.82), or high (P=.09 and P=.68) nuclear grades. There was no correlation between intratumoral CD163 content and DCIS grade (P=.257). A trend for higher stromal CD163 expression was seen with higher-grade DCIS, although not statistically significant (P=.178). In conclusion, CD163 on breast core biopsy does not help select patients who may safely forgo excision of DCIS. (C) 2018 Elsevier Inc. All rights reserved.