J Natl Cancer Inst. 2021 May 19:djab095. doi: 10.1093/jnci/djab095. Online ahead of print.
ABSTRACT
BACKGROUND: The prognostic significance of patients with low-risk Recurrence Score (RS) results in the context of the American Joint Committee on Cancer (AJCC) 8th-edition pathologic prognostic staging has not been investigated. We evaluated if expanded RS criteria can be considered for downstaging in AJCC pathologic prognostic staging.
METHODS: Using Surveillance, Epidemiology, and End Results data we identified patients with T1-3N0-3M0 HR-positive/HER2-negative breast cancer treated from 2010-2015 with follow-up data through 2016. We evaluated TNM categories, grade, and RS result. The primary outcome measured was 5-year disease-specific survival (DSS) of patients with low-risk RS results not already pathologic prognostic stage IA, determined by T and N categories per AJCC 8th edition. All statistical tests were 2-sided.
RESULTS: Of 154,050 patients with median follow-up of 49 months (range = 0-83), RS results were obtained in 60,886 (39.5%): RS was <11 in 13,570 (22.3%), 11-17 in 22,719 (37.3%), 18-25 in 16,521 (27.1%), and ≥ 26 in 8,076 (13.3%). Five-year DSS for pathologic prognostic stage IA patients (n = 114,910, 74.6%) was 98.8%. Among N0-1 patients with RS < 18 not staged as pathologic prognostic stage IA by current criteria, 5-year DSS was excellent and not statistically significantly different than for pathologic prognostic stage IA patients (97.2%-99.7%, P > .05). For those with RS 18-25, there was a small decrease in DSS for T2N0 (2.3%) and modest decrease for T1-2N1 (4.2%-6.4%) compared to pathologic prognostic stage IA patients (P < .001).
CONCLUSION: Patients with RS < 18 have excellent 5-year DSS regardless of T category for N0-1 disease suggesting further modification of the AJCC staging system using this cutoff.
PMID:34010423 | DOI:10.1093/jnci/djab095
