Breast atypia: timing of progression to subsequent clinically significant event


Surgical Breast Oncology, Aurora Comprehensive Breast Care Center, Aurora Research Institute, Department of Pathology

Presentation Notes

Presented at 2013 Aurora Scientific Day, Milwaukee, WI


Background/significance: Atypical hyperplasia (AH) increases a woman’s risk for breast cancer. This can cause significant anxiety, leading women to choose risk reduction options of tamoxifen and/ or prophylactic mastectomies.

Purpose: Understanding the natural history of AH and subsequent breast cancer may help patients select and time options for risk reduction.

Methods: Aurora Health Care’s experience was retrospectively reviewed for women initially diagnosed with pure breast AH, either atypical ductal hyperplasia (ADH) and/or atypical lobular hyperplasia (ALH). 31,921 patients with the ICD-9 code of 610.8/.9 (other specified or unspecified benign breast disorder) were screened between 1/1995-12/2010. After elimination of repetitive diagnoses from multiple visits, non-breast disease, non-atypical benign breast disease, and previous diagnosis of breast malignancy, the study cohort consisted of 370 breasts with a principal diagnosis of pure AH involving 360 patients. Slides were reviewed by a single pathologist, blinded to the original diagnosis. Those patients who progressed to a subsequent clinically significant event (SCSE), i.e., another diagnosis of AH (increasing the calculated Gail Model 5-year and lifetime risk of breast cancer) or malignancy were analyzed for race, age, SCSE pathology, laterality, medical/surgical risk intervention, and time to progression.

Results: 31(8.61%) patients developed a SCSE. Mean age at initial diagnosis of AH was 57.9 years (SD 10.6, range 29-84). Racial makeup was similar to controls: 27 (87.1%) Whites, 3 (9.6%) Blacks. 18 (58.1%) developed the SCSE within the ipsilateral breast, and 13 (41.9%) within the contralateral breast (p=0.369) whether the initial diagnosis was ADH, ALH, or mixed (p=0.405). Regarding histology of the 2nd event, 14 (45.2%) were diagnosed again with AH, 5 (16.1%) progressed to carcinoma in situ (CIS), and 12 (38.7%) progressed to invasive carcinoma (IC) (p=0.115). Resection of the AH did not reduce the chance of SCSE within the ipsilateral breast (p=0.924). Of those 31 who developed a SCSE, 3 (9.7%) had taken tamoxifen, which did not influence subsequent histology. Time to development of recurrent AH, CIS, and IC was 2.87, 2.64, and 5.12 years, respectively (p=0.038), uninfluenced by type of atypia diagnosed (p=0.595).

Conclusion: Time to progression from AH to IC, in our series, is approximately 5 years. However, we cannot identify which patients with AH will develop malignancy, highlighting the need for prognostic biomarkers for more effective risk stratification.

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