Does the 21-gene recurrence score have clinical utility in
HR+/HER2+ breast cancer?
by Nadeem Bilani, Fionnuala Crowley, Mohammad Mohanna, Mira
Itani, Marita Yaghi, Diana Saravia, Iktej Jabbal, Barbara Dominguez, Hong
Liang, Zeina Nahleh
The Breast: September 06, 2022
The 21-gene recurrence score assay has been validated as a
predictive biomarker in early-stage HR+ and HER2-breast cancer. It is not
indicated for use in HER2+ disease based on national guidelines. In this study,
we assessed the value of 21-gene recurrence score, or OncotypeDX (ODX), testing
in HR+/HER2+ breast cancer.
We used the National Cancer Database to identify patients
with stages I-II, HR+/HER2+ breast cancer who received multi-gene testing with
ODX. We the explored the prognostic and predictive value of this biomarker
through various forms of survival modeling.
ODX testing was performed in n = 5,280 patients. N = 2,678
patients (50.7%) had a RS < 26, while n = 2,602 (49.3%) had a RS≥26. In
Kaplan-Meier survival modeling for patients with recurrence scores <26,
there was no significant difference in overall survival (p = 0.445) between
patients receiving different systemic treatment regimens. However, when
recurrence scores were ≥26, there was a statistically-significant difference in
overall survival between systemic treatment regimens (p < 0.001). 5-year
overall survival was highest (97.4%) for patients receiving triple therapy
(anti-HER2 with chemotherapy and endocrine therapy), followed by those
receiving dual therapy with endocrine and anti-HER2 (96.7%), and endocrine with
chemotherapy (94.9%). Patients receiving endocrine therapy alone exhibited the
lowest 5-year overall survival (88.5%).
Results
from this large national cancer registry suggest that
multigene testing may have predictive value in treatment selection of patients
with early-stage, HR+/HER2+ breast cancer. Prospective trials are warranted to
identify subgroups of patients with HR+/HER2+ breast cancer who can be spared
anti-HER2 treatments and cytotoxic chemotherapy.
