Second breast cancer: recurrence score results, clinicopathologic characteristics, adjuvant treatments, and outcomes—exploratory analysis of the Clalit registry

Abstract Data on using the 21-gene Recurrence Score (RS) testing on second breast cancer (BC; second primary or local recurrence) are lacking. This cohort study examined patients with first and second BC, who underwent 21-gene testing both times. It included a ‘study-cohort’ (60 N0/N1mi/N1 ER + HER2‒ BC patients with ≥2 RS results >1 year apart) and a ‘general 21-gene-tested BC-cohort’ (2044 previously described N0/N1mi/N1 patients). The median time between the first and second BC was 5.2 (IQR, 3.1–7.1) years; the second BC was ipsilateral in 68%. Patient/tumor characteristics of the first- and second-BC in the ‘study-cohort’ were similar, except for the RS which was higher in the second BC (median [IQR]: 23 [17–30] vs 17 [14–22], p < 0.001). Overall, 56 patients had follow-up data, of whom 5 experienced distant recurrence (2 RS 11–25 patients and 3 RS 26–100 patients). Studies exploring the prognostic utility of the RS in this setting are warranted

Clinical outcomes in estrogen receptor-positive early-stage breast cancer patients with Recurrence Score 26-30: observational real-world cohort study

Abstract Data on adjuvant chemotherapy (CT) benefit in ER + HER2‒ early-stage breast cancer (EBC) patients with Recurrence Score (RS) 26-30 are limited. This real-world study evaluated the relationships between the RS, adjuvant treatments, and outcomes in 534 RS 26-30 patients tested through Clalit Health Services (N0: n = 394, 49% CT-treated; N1mi/N1: n = 140, 62% CT-treated). The CT-treated and untreated groups were imbalanced (more high-risk clinicopathologic characteristics in CT-treated patients). With median follow-up of 8 years, Kaplan–Meier estimates for overall survival (OS), distant recurrence-free survival (DRFS), and BC-specific mortality (BCSM) were not significantly different between CT-treated and untreated N0 patients. Seven-year rates (95% CI) in CT-treated vs untreated: OS, 97.9% (94.4–99.2%) vs 97.9% (94.6–99.2%); DRFS, 91.5% (86.6–94.7%) vs 91.2% (86.0–94.6%); BCSM, 0.5% (0.1–3.7%) vs 1.6% (0.5–4.7%). For N1mi/N1 patients, OS/DRFS did not differ significantly between treatment groups; whereas BCSM did (1.3% [0.2–8.6%] vs 6.2% [2.0–17.7%] for CT-treated and untreated patients, respectively, p = 0.024)