Background: OncotypeDX(®) (ODX) is a well-validated assay for breast cancer treatment planning. We explored whether the conventional pathological factors could pick up high risk patients without the help of the ODX.
Methods: The ODX was performed on 139 hormone receptor-positive invasive breast cancers in a single Japanese institution. The recurrence risk was compared between the ODX and the St. Gallen Consensuses. The correlations were analyzed between the Recurrence Score (RS) measured by ODX and the pathological factors. In addition, we performed a follow-up survey and examined the association of the RS with the confirmed recurrence or death.
Results: The ODX classified 68 (49 %) as low RS, 52 (37 %) as intermediate RS, and 19 (14 %) as high RS cases. Correlations were noted between RS and progesterone receptor (PR) (r = -0.53), Ki-67 (r = 0.42), and nuclear grade (NG) (r = 0.41). None had a high RS with PR(3+) or NG1. Only one high RS patient had a Ki-67 (<20 %). The combinations of high RS with PR(0)/Ki-67 (≥20 %) and PR(1+)/Ki-67 (≥20 %) were 70 and 58 %, respectively. The combinations with high RS and PR(0)/NG3, PR(0)/NG2, and PR(1+)/NG3 were 83, 75, and 75 %, respectively. The median follow-up was 39.1 months (range 24.0-67.8). There were one low RS (1 %), four intermediate RS (8 %), and three high RS patients (16 %) who developed local or distant recurrence.
Conclusion: Hormone receptor-positive invasive breast cancers are stratified with the combinations of PR/Ki-67 or PR/NG. Some of the high recurrence risk cases might be identified without the ODX.