Background: Recurrence score (RS) testing in early-stage, ER-positive breast cancer is used to predict the benefit of adjuvant chemotherapy for disease recurrence and overall survival. TAILORx results decreased the ambiguity of "intermediate risk" RS by creating a binary classification system. We aimed to determine how women ≥ 70 years with intermediate RS were redistributed post-TAILORx and to identify predictors of low RS.
Methods: Patients ≥ 70 years with early-stage, node-negative, ER-positive breast cancers in the National Cancer Database(2006-2014) were included. "Pre-TAILORx" RS were classified as low (0-17), intermediate (18-30), and high (> 30). "Post-TAILORx" RS were classified as low (0-25) and high (> 25).
Results: In total, 14,925 women were included. Average age was 74 years. 60% (n = 9009) had low pre-TAILORx RS, 31% (n = 4635) intermediate, and 9% (n = 1281) high. Of 4635 patients with intermediate RS, 72% (n = 3660) were reclassified to low RS. Only 12% (n = 1783) of patients received chemotherapy. Of patients with pre-TAILORx intermediate RS who received chemotherapy, 55% (n = 417) would have been spared chemotherapy by being reclassified with low RS post-TAILORx. The strongest predictor of post-TAILORx low RS was tumor grade; 95% of well-differentiated had low RS, compared with 56% of poorly/undifferentiated tumors (p < 0.001). Smaller tumor size also was associated with low RS. Age was not associated with RS.
Conclusions: With post-TAILORx RS criteria, the vast majority of patients ≥ 70 years can be classified as low-risk and unlikely to benefit from chemotherapy. Given that the elderly have greater rates of chemotherapy-associated complications, reconsideration of routine RS testing in patients ≥ 70 years is warranted. Tumor grade and size also may inform the decision to omit RS testing.