Abstract The association between hormone replacement therapy (HRT) and breast cancer risk in women with benign breast disease (BBD) is unclear. However, others have shown that HRT use is associated with the development of proliferative breast disease (Rohan et. al, CEBP 2008). To better clarify potential risks associated with postmenopausal hormone use in women with BBD, we performed a nested case control study within the Mayo Clinic Benign Breast Disease Cohort. In the cohort, there are 11,079 women who had benign breast biopsies between 1967 and 1996 and for whom we have outcome and risk factor data, including use of HRT. We studied 947 cases (breast cancer after BBD) and two controls matched to each case based on age and year of BBD. Information on use of HRT was obtained through use of questionnaires and medical record review with a mean time of follow up of 17.4 years. HRT use, histology, involution status, and family history were all evaluated for impact on breast cancer risk in a multivariate model. As shown in Table 1, when looking at effects of histology, involution, and family history, we confirmed previously reported findings of risk (Hartmann LC et. al, NEJM 2005). Specifically, we saw increased risk in women with AH vs. PDWA or NP, decreased risk with complete involution vs. partial or no involution, and increased risk with strong family history vs. weak or no family history. Associations of hormone replacement therapy and other relevant clinical variables with risk of breast cancer Multivariate model simultaneously including all variables listed in the table. HRT=hormone replacement therapy. NP=non-proliferative. PDWA=proliferative disease without atypia. AH=atypical hyperplasia We found that women who had used HRT had no higher risk of developing breast cancer than women who had not used HRT. Specifically, with Never Users as the reference group, those with 5 years or less exposure had OR 0.80 (0.56-1.15); 6-10 years, 0.85 (0.56-1.28) and 11+ years, 0.51 (0.36-0.72), p =0.002. In conclusion, we found that HRT use among postmenopausal women with BBD was not associated with an increased risk of breast cancer. In this case-control set, we confirmed previous findings regarding well established risk factors of histology, involution status, and family history. While HRT use may contribute to the development of proliferative breast disease, we do not see that HRT is associated with additional breast cancer risk, beyond that of the proliferative disease itself. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-09-03.
Abstract Abstract #3103 Introduction: Lymphedema is well-known in the arm but can also occur in the breast. Diagnosis is currently non-standardized and based on clinical impression. We sought to determine if skin thickness could serve as a useful measure in the diagnosis of breast lymphedema (BLE).
 Methods: Patients undergoing unilateral non-mastectomy procedures were enrolled on this prospective clinical study preoperatively and evaluated for signs and symptoms of lymphedema in the operated breast in the postoperative period. Patients with established BLE were also studied. BLE diagnosis was independent of ultrasound findings and was based on a graded physical exam targeting clinical signs of edema and erythema. Skin thickness was measured with ultrasound at the 6 o'clock position of both breasts. Differences in skin thickness were assessed by the ratio of skin thickness in the operated and contralateral breasts, with comparison of means by two-sample t-test. Receiver operating characteristic curves were constructed to estimate the area under the curve (AUC) and to determine optimal cutpoints.
 Results: Ninety-seven women were studied; 85 were enrolled preoperatively and 12 postoperatively after a diagnosis of BLE. Median length of follow-up overall was 8 months. Of the 97 women, 46 had BLE at one or more follow-up visit with median time to first diagnosis of 3 months. Mean measured skin thickness was 2.3 ± 0.5mm in unaffected breasts and 3.2 ± 1.0 mm in operated breasts. Women with BLE had significantly greater skin thickness in the operated breast compared to the contralateral breast, with a mean skin thickness ratio of 1.83 ± 0.57 in patients with BLE compared to 1.18 ± 0.40 among those without BLE (p<0.0001). Skin thickness ratio provided excellent discrimination for BLE, with an area under the curve (AUC) of 0.86. At a ratio of 1.32 or greater (32% greater skin thickness in operated versus contralateral breast), sensitivity and specificity for diagnosing BLE were 81% and 82% respectively. A single measure of skin thickness in the operated breast also correlated well with diagnosis of BLE, with skin thickness of 3.2 mm or greater demonstrating sensitivity of 78% and specificity of 82%, AUC 0.82.
 Conclusions: Breast lymphedema results in skin edema and increased skin thickness that can be quantified with ultrasound. Measuring breast skin thickness- either as a single reading or as a ratio to the unaffected breast- may be useful in the diagnosis of breast lymphedema. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3103.