Posted: Tuesday, April 25, 2023
The landmark breast cancer study TAILORx yielded evidence-based answers to the question of which patients with estrogen receptor–positive and HER2-negative early breast cancer may benefit from adjuvant chemotherapy and which patients could pursue endocrine therapy instead. Although the 21-gene recurrence score (0–100) used in TAILORx was originally established to assess distant recurrence of breast cancer, it has been unclear whether the 21-gene recurrence score was weighted for the recurrence over survival prognosis.
Sherry X. Yang MD, PhD, of the National Cancer Institute, Rockville, Maryland, and colleagues investigated the 21-gene recurrence score on the choice of clinical endpoints in TAILORx: overall survival, invasive disease–free survival, recurrence-free interval, and distant recurrence–free interval. Recently presented at the American Association for Cancer Research (AACR) Annual Meeting 2023 (Abstract LB119/2), their data uncovered a need to establish biomarkers directly related to overall or disease-free survival to more precisely target survival as a clinical outcome.
Although both midrange (11–25) and high-range (26–100) 21-gene recurrence scores were associated with recurrence-free interval, high-range scores alone were associated with disease-free survival. Of note, these high-range scores were not significantly associated with overall survival in the multivariable Cox proportional–hazards regression models. Of 462 deaths, 33.1% (153) were attributed to breast cancer, and 91.8% (424) were associated with disease-free survival–related events including other cancers (24.5%), breast cancer (33.1%), or unknown reasons (34.2%). Thus, disease-free survival was considered the most representative surrogate endpoint for overall survival measured by the researchers, yet it was found to be imperfect.
Disclosure: The study authors reported no conflicts of interest.