Genomic profiling of hormone receptor positive breast cancer outperforms CP factors in predicting the outcomes. This has led to wider application of genomic testing for risk stratification. This can lead to avoidance of chemotherapy in patients with favorable outcomes.
Patient with T1, T2, node negative estrogen and or Progesterone receptor positive Her 2 Negative breast cancer, regardless of age, menopausal status, Grade or Ki67 were eligible for risk prediction using the Oncotype DX RS. All patient who had RS were included from March 2012- September 2017. The test was sent out and done in reference laboratory (Genomic Health). The original cut off of Low RS (<18), Intermediate RS18-31 and high RS > 31 was used. Patient with low RS were spared chemotherapy. While those high score received chemotherapy. Intermediate risk was preferably given chemotherapy. The changes in therapy based on RS score were reordered as compared to CP factors (St. Gallen Criteria). The disease free and overall survival was analyzed.
Complete data was available for 141 Patients. Median age was 51 years (30-78). 54% premenopausal. 97% ductal histology. Grade correlated with RS with higher grade having higher RS. There was 67% reduction in use of adjuvant chemotherapy when compared to decision based on CP factors while 1 patient had escalation of therapy based on RS. Median follow up was 32 months (3-73 months). The 5 year estimated DFS was 95%. The overall survival was 98%. Only recurrence score correlated with DFS p = 0.04 while age, Ki67, grade, tumor size did not.
Our data in a younger group of mainly premenopausal women with early breast cancer is consistent with the published date about the prognostic value of RS. A substantial percentage of these patient can be spared chemotherapy and its related toxicity without adversely affecting the long-term outcomes. Utilizing RS in decision making may potentially be cost effective.
Clinical trial identification
Legal entity responsible for the study
The breast cancer group at KFSH.
Has not received any funding.
All authors have declared no conflicts of interest.