Comparison of Oncotype DX™ Recurrence Score by Histologic Subtype of Breast Carcinoma
Philip E Bomeisl, Cheryl L Thompson, Lyndsay N Harris, Hannah L Gilmore. University Hospitals Case Medical Center, Cleveland, OH; Seidman Cancer Center, Cleveland, OH
Background: Oncotype DXTM is a commonly used 21 gene assay that predicts the benefit of chemotherapy for node-negative patients with all types and grades of estrogen receptor-positive breast cancer. Results are used to determine which patients may benefit from adjuvant chemotherapy. Though some data exists demonstrating that traditional pathologic features can predict score, there is little information published correlating specific histologic subtype of cancer and recurrence score (RS).
Design: The pathology database was searched for all Oncotype DXTM reports from 1/1/2008 to 10/1/2012. The corresponding original pathology reports were reviewed to determine histologic subtype, grade, and ER/PR/HER2 status. The pathologic features were compared with the Oncotype DXTM report data.
Results: A total of 146 cases were identified. The histologic subtypes seen were invasive ductal carcinoma (IDC, 71.2%), invasive lobular carcinoma (ILC, 15.8%), mixed invasive ductal and lobular carcinoma (ID+LC, 8.9%), invasive mucinous carcinoma (IMC, 2%), mixed invasive ducal and mucinous carcinoma (ID+MC, 1.4%) and tubular carcinoma (TC, 0.7%). These categories were stratified by grade and RS. Not unexpectedly, amongst the IDCs, higher grades were associtaed with a much greater likelihood of having a high RS (p<0.001). Most tumors with high RSs were IDCs. 15.4% of all IDC vs. 2.1% of the remainder of the tumor histologic types fell into this category.
|Low (0-17)||Intermediate (18-30)||High (31-100)|