br Results br Patient Characteristics br
3.1. Patient Characteristics
Characteristics of patients undergoing Recurrence Score (RS) testing.
N = Percent N = Percent
Traditional RS Risk Group
TAILORx RS Risk Group
Year of Diagnosis
Lymph Node Status
HER2/neu Statusa N =
a Denotes that KX2-391 HER2/neu status was reliably collected in SEER after 2010 and is there-fore presented for patients collected beyond 2010.
Among the patients who underwent testing, the TAILORx RS distribu-tions for the young cohort are as follows: 15% of patients were high risk, 61% of patients were intermediate risk, and 24% of patients were low risk. Among the older cohort with RS testing, 16% had high-risk RS, 55% had intermediate-risk RS, and 29% had low-risk RS (Table 1). Distribution of RS amongst tested patients is displayed in Fig. 1 for ages 18–49, 50–69, and 70 and older.
Utilization of chemotherapy among RS tested patients was 24% in the young cohort and 12% in the older cohort (p b .001). In the young cohort, 73% (3772) of patients in the high-risk TAILORx RS
Fig. 1. Distribution of recurrence scores based on TAILORx categorizations for age groups 18–49, 50–69, and 70 or older.
categorization received chemotherapy, 38% (9344) of patients with in-termediate-risk RS categorization received chemotherapy, and 9% (3322) of low-risk RS categorization received chemotherapy. In the older cohort, 52% (489) of patients in the high-risk RS categorization re-ceived chemotherapy, 16% (607) of patients with intermediate-risk RS categorization received chemotherapy, and 3% (225) of patients with low-risk RS categorization received chemotherapy.
3.2. Factors Associated With Recurrence Score Testing
We evaluated the factors associated with RS testing in both cohorts (Table 2). In the older cohort, we found an increased odds of RS testing in later years of diagnosis 2010–2014 (compared to 2004–2009) and stage II disease when compared with stage I. Factors associated with de-creased odds of RS testing were increasing age (age ≥ 80 compared to age 70–79), race (Asian and other compared to non-Hispanic white), PR negative status, LN positive status, tumor size N5 cm, grade III, and stage III tumors. Findings were similar amongst the younger cohort.
3.3. Factors Associated With Survival
A Cox proportional hazard model was performed among all patients who underwent RS testing to evaluate factors associated with survival (Table 3). In the young cohort, factors associated with a higher hazard ratio (HR) of death included: increasing age, black race, LN-positivity, larger tumor size of 2–5 cm (compared to tumor size b2 cm), grade III tumors (compared to grades I and II), and high-risk TAILORx tumor cat-egorization (compared to low-risk).
In the older cohort, factors associated with higher HR of death in-cluded: increasing age (age ≥ 80 compared to age 70–79), black race (compared to non-Hispanic white race), LN-positivity, and high-risk TAILORx tumor categorization (compared to low-risk).
3.4. Factors Associated with Survival in Patients with High-Risk Recurrence Score Categorization
Kaplan Meier survival curves were created to measure overall sur-vival in all patients with a high-risk TAILORx RS (Fig. 2). These curves
Multivariable regression analysis evaluating factors associated with the probability of un-dergoing Recurrence Score testing.
Patients aged 18–69 Patients aged 70 years
Non-Hispanic White REF
Year of Diagnosis
Progesterone Receptor Status
Lymph Node Status