Molecular Subtype of Breast Carcinoma: Comparison of the Incidence, Locoregional Recurrence and Distant Metastasis between African American and Caucasian Women.
Dana L Johnson, Hope T Richard, Celeste N Powers, Michael O Idowu. Virginia Commonwealth University, Richmond
Background: While there is improved overall 5 year survival in breast cancer patients, African American (AA) women seems to lag behind Caucasians (C). There are several reports of an aggressive molecular subtype of breast cancer disproportionately affecting AA women. Our aim is to determine the incidence of the different molecular subtypes of breast cancer in AA and C; and to determine locoregional recurrence and distant metastasis in AA and C in the different molecular subtypes.
Design: Cases of breast cancer in women with follow-up information from 1999 to 2010 were reviewed. The cases were divided into Luminal A (either ER and/or PR+, Her2-), Luminal B (either ER and/or PR+, Her2 +/-), HER2(ER-, PR-, Her2+) and Triple negative (TN)(ER-,PR-,Her2-. We did not further subclassify the TN phenotype into basal-like or non basal like. Each molecular subtype was then subdivided into AA and C. Other minority racial categories were excluded. Presnce of locoregional recurrence (in the breast or axilla) or distant metastasis was determined from the clinical/pathologic follow-up information. Only patients with follow-up of at least 48 months are included in the study.
Results: Of the 6,646 consecutive breast cancer patients during the study period, 810 patients had adequate follow-up information and were included in the study. The median ages at presentation are shown in Table 1. The predominant molecular phenotype in all patients is luminal A with 530 patients (66%C, 34%AA), however, there were disproportionately more locoregional recurrence and distant metastasis in AA. There were 75 with Luminal B (80%C, 15%AA), 42 with Her2 (50%C, 50%AA), and 163 with TN (37%C, 63%AA) respectively. There were almost twice as many metastases in AA compared to C in the Her2 and TN phenotype. With the exception of luminal B, AA showed disproportionately higher rates of locoregional recurrence and distant metastasis.
|Luminal A(n=530)||Luminal B(n=75)||Her2(n=42)||Triple Negative(n=163)|
|C(N=348)||AA(N=182)||C(N= 60)||AA(N=15)||C(N=21) / AA(N=21)||C(N=61)||AA(N=102)|
|Locoregional recurrence||4(1%)||5(2.7%)||1(1.7%)||0(0%)||1(4.8%) / 1(4.8%)||1 (1.6%)||5 (4.9%)|
|Locoregional recurrence||8(2.3%)||12(6.6%)||8(13.3%)||2(13.3%)||2(9.5%) / 4(19%)||5(8.2%)||20(19.6%)|
|Median Age (yrs) at presentation||56||55||49||47||54 / 49||54||52|