The Influence of Body Mass Index on the Histopathology and Outcomes of Patients Diagnosed with Atypical Breast Lesions.

Background: Multiple studies have demonstrated a link between obesity and breast cancer; however, the potential association between obesity and atypical high-risk breast lesions has not been well characterized. We sought to evaluate the characteristics and clinical outcomes of patients with breast atypia based on a woman's body mass index (BMI).
Methods: We retrospectively identified adult women diagnosed with atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), and/or lobular carcinoma in situ (LCIS) at a single institution from 2008 to 2017. BMI groups were defined as a BMI 18.5 to < 30 or BMI ≥ 30 (obese). Adjusted logistic regression was used to estimate the association of BMI group with the odds of (1) upstage to cancer after atypia on needle biopsy, and (2) subsequent diagnosis of breast cancer.
Results: Breast atypia was identified in 503 patients (most advanced atypia: 74.8% ADH, 4.6% ALH, 20.7% LCIS), and 41% of these patients were classified as obese. After adjustment, BMI group was not associated with upstage to breast cancer at surgical excision following needle biopsy (p = 0.16) or development of a subsequent breast cancer (p = 0.08). For those upstaged to breast cancer at the time of surgical excision, or those who developed a subsequent malignancy, tumor subtype, grade and stage were not associated with BMI group (p > 0.05).
Conclusion: In a large cohort of patients diagnosed with atypical breast histology, the risk of upstaging and/or subsequent progression to a breast malignancy was not associated with BMI. Factors other than obesity may influence breast cancer risk.
(© 2022. Society of Surgical Oncology.)