Background: The Clinical Treatment Score post-5 years (CTS5) is a risk stratification tool used to determine the risk of late recurrence in hormone receptor-positive (HR+), HER2-negative breast cancer (BC). Limited data exist on its use in HR+, HER2-positive (HER2+) BC.
Patients And Methods: CTS5 was evaluated in HR+, HER2+ BC in the North Central Cancer Treatment Group (NCCTG) N9831 (Alliance) and NSABP B-31 (NRG) trials.