Abstract 3569: Age distribution at prior benign biopsy (PBB) in breast cancer patients and implications for risk biomarker discovery

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL Age distribution at prior benign biopsy (PBB) in breast cancer patients and implications for risk biomarker discovery. Background: Improvements in breast cancer risk estimation are badly needed, and biomarkers present in breast tissue are attractive for a number of reasons. These can be identified in retrospective archives of breast tissue assembled from prior benign biopsy (PBB) samples of women who subsequently developed breast cancer. We are conducting a case-control study using such material, and have noted a paucity of young or premenopausal cases in our study population to date. We present an analysis of our data so far, to ask the question whether PBB material will be suitable for identifying risk markers for premenopausal and early-onset breast cancer. Notably, this question has not been addressed in the existing literature. Methods: We examined the ages at PBB and cancer in a group of women whose samples are being assembled for a case-controls study of breast cancer risk biomarkers. Subjects are designated cases if they were diagnosed with DCIS or invasive breast cancer and had a history of PBB at least one year prior to cancer diagnosis. Only cases were used for this analysis. Differences in age distribution and histologic findings between women undergoing PBB before age 45 were compared to those who were ≤ 45 years at PBB, using tests of proportion and chi square tests. Results: A total of 213 breast cancer cases with PBB have been identified so far; mean age at PBB was 51.4 years, (SD 10.6) with 59/213 women (27.7%) undergoing PBB at age < 45 years. The mean age at cancer diagnosis was 57.3 years (SD 10.7), with 22/213 women (10.8%) being diagnosed with breast cancer at age <45 years. The mean interval between PBB and cancer diagnosis was 6 years (SD 4.3). Women who were under 45 years at the time of PBB had a histologic diagnosis of fibroadenoma in 25/58 (43%), compared to 16/154 (10.4%) in those β45 years. In contrast, atypical lesions comprised 8.7% of PBB in women <45, and 14.2% in women β45 years (p<0.000). There was a highly significant tend towards increasing severity of histology in PBB samples and increasing age at PBB (p=0.000). A weak but significant inverse relationship was present between age at PBB and the interval from PBB to cancer diagnosis (p=0.012). Conclusions: These results suggest that the PBB model is likely to be useful for the identification of risk biomarkers for older and postmenopausal women, but appears to be of questionable value in the identification of biomarkers for risk of cancer earlier in life. This is particularly true if studies are designed to focus on atypical epthelial lesions, since these are infrequent in young women. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3569. doi:1538-7445.AM2012-3569