Abstract 3593: Tumor size and lymph node metastases in African-American and European-American women with breast cancer
Authors: Roberts Michelle , Bandera Elisa V. , Hwang Helena , Ciupak Gregory , Zirpoli Gary R. , Yao Song , Pawlish Karen , Davis Warren , Jandorf Lina , Bovbjerg Dana H. , Ambrosone Christine B. 
Published: August 2012

Few studies have evaluated lymph node metastasis in African-American (AA) women with breast cancer, who are more likely to be diagnosed at an advanced stage and with lymph node positive tumors. Likelihood of nodal involvement increases with tumor size, although recent data have indicated that this may not be true for AA breast cancer patients and patients with basal-like tumors. Nodal metastases are also more likely in premenopausal AA patients compared to either premenopausal European-American (EA) patients or postmenopausal AA and EA patients. We examined risk factors for lymph node metastasis at breast cancer diagnosis in AA and EA women, and investigated the contributions of race, tumor subtype, and menopausal status to the tumor size-lymph node metastasis relationship. This analysis included 805 women diagnosed with primary, incident breast cancer enrolled in the Women's Circle of Health Study, a case-control study of AA and EA breast cancer patients and healthy women. Cases were identified using hospital-based ascertainment in New York City hospitals with high referral patterns for AA women and through population-based ascertainment in New Jersey using the State Cancer Registry. Eligible cases were self-identified AA and EA women age 20-75 with no previous history of cancer other than nonmelanoma skin cancer. In-person interviews were conducted and consent to review pathology reports was obtained. Tumor size was categorized as tumors 2 cm or less (small tumors) and tumors greater than 2 cm (large tumors). Unconditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI). AAs with small tumors were more likely to be node positive compared to EAs (OR=1.24, 95% CI 0.81-1.88) while among patients with large tumors, AAs were less likely to be node positive (OR=0.83, 95% CI 0.49-1.41). When grouped by race and tumor subtype, we found that the triple negative subtype was associated with a decreased risk of nodal metastases among EA women with small tumors (OR=0.17, 95% CI 0.04-0.79) and a nonsignificantly decreased risk among AA women with large tumors, using the luminal A subtype as the referent group. Associations were null in EA women with large tumors and AA women with small tumors. When grouped by race and ER status, ER negativity was associated with a decreased risk of nodal metastases among AA women with large tumors (OR=0.41, 95% CI 0.20-0.84), while AA women with small tumors were at increased risk (OR=1.90, 95% CI 0.92-3.91). Our data suggest an effect of race and tumor subtype on the relationship between tumor size and likelihood of lymph node metastases. Tumor size appears to affect lymph node metastasis differently by race, a mechanism that is modified by tumor biology. Our findings support the hypothesis that in AA breast cancer patients, large tumors may not be more likely to give rise to metastatic lymph nodes.

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 3593. doi:1538-7445.AM2012-3593