Evaluation of Exogenous Estrogen Use in Patients with Lobular Neoplasia and its Role in Subsequent Breast Cancer Development

Abstract

Objective: There is a paucity of data around the impact of exogenous hormones on future breast cancer risk in the setting of Lobular Neoplasia (LN). We sought to determine if patients with history of exogenous hormone use who develop LN are more likely to develop a future breast cancer. Methods: Following IRB approval, a single-institution retrospective review was conducted of patients diagnosed with LCIS or ALH between 1/2009 and 12/2017. Use of exogenous hormones and future breast cancer was examined. Data were analyzed using IBM SPSS version 29.0.2.0. Results: A total of 88 patients with LN were identified; 57 (65%) with LCIS and 31 (35%) with ALH. At time of LN diagnosis, 53 (60%) underwent surgical excision, 48 (39%) were followed in a high-risk clinic, and 13 (15%) took anti-estrogen therapy for risk reduction. 15 patients had a history of hormone therapy (HT) use prior to LN diagnosis (17%) and 3 (3%) started HT following LN diagnosis. Median overall follow-up was 9.7 years (interquartile range [IQR] 7.2–11.4). Eleven (13%) patients developed breast cancer. Comparing those who developed breast cancer vs. not, there was no difference in HT use (9% vs 21%, p=0.325), vaginal estrogen use (27% vs 9%, p=0.110), OCP use (54% vs 64%, p=0.675), or other hormone-based birth control (27% vs 14%, p=0.402). Conclusion: In a single-institution cohort with long-term follow up, future development of breast cancer in patients diagnosed with LN was not associated with prior use of HT, OCPs, vaginal estrogen or other hormone-based birth control use.