Pregnancy-Associated Breast Changes after Nipple-Sparing Mastectomy.

BACKGROUND: Women of reproductive age are chronically underrepresented in breast cancer studies. Recent studies suggest that almost 40% of patients diagnosed with breast cancer who are of reproductive age want to have children after completing treatment. In this study, the authors evaluated patients of reproductive age who had undergone nipple-sparing mastectomy (NSM) and implant-based reconstruction. The authors compared those who became pregnant with those who did not with respect to clinical and radiologic changes that are reported at follow-up. METHODS: Any patient 45 years of age or younger at the time of NSM was determined to be of reproductive age, selected for evaluation, and followed prospectively. The presence or absence of breast examination changes in the setting of pregnancy after NSM was recorded. RESULTS: A total of 36 patients became pregnant after NSM, and 158 patients did not become pregnant after NSM. Of those who became pregnant, nearly half reported some clinical change just before or immediately after delivery. These changes included color change and discharge at the residual nipple-areola complex and palpable nodularity elsewhere. For those with palpable changes, an ultrasound was performed and hypoechoic lesions with variable vascularity were identified. For those who went on to excision, lactational hyperplasia was the most common diagnosis. CONCLUSIONS: Ultrasound is an appropriate first-line investigation of breast changes, which can include hyperplasia of remaining ductal and glandular tissue. Patients who became pregnant after NSM commonly had clinical breast examination changes, but the majority of these changes were found to be benign on further evaluation. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, II.

SPARC enables genetic manipulation of precise proportions of cells.

Many experimental approaches rely on controlling gene expression in select subsets of cells within an individual animal. However, reproducibly targeting transgene expression to specific fractions of a genetically defined cell type is challenging. We developed Sparse Predictive Activity through Recombinase Competition (SPARC), a generalizable toolkit that can express any effector in precise proportions of post-mitotic cells in Drosophila. Using this approach, we demonstrate targeted expression of many effectors in several cell types and apply these tools to calcium imaging of individual neurons and optogenetic manipulation of sparse cell populations in vivo.