Article
Author: Lastdrager, Willem B ; Volders, José H. ; Tetteroo, Geert W. M. ; Hunting, Jarmo C B ; de Valk, Bart ; Vrijaldenhoven, Suzan ; van Maaren, Marissa C ; Timmer-Bonte, Anja N. H. ; Smorenburg, Carolien H. ; Imholz, Alex L T ; van der Velden, Annette W G ; Volders, José H ; van Maaren, Marissa C. ; Smilde, Tineke J ; van Dalen, Thijs ; Lastdrager, Willem B. ; Blanken-Peeters, Charlotte F J M ; Kuijer, Anne ; Imholz, Alex L. T. ; Hunting, Jarmo C. B. ; Zuetenhorst, Hanneke M ; Haringhuizen, Annebeth W. ; Haringhuizen, Annebeth W ; Blanken-Peeters, Charlotte F. J. M. ; Smilde, Tineke J. ; Verreck, Eline E F ; Nieboer, Peter ; Siesling, Sabine ; Smorenburg, Carolien H ; Zuetenhorst, Hanneke M. ; Verreck, Eline E. F. ; Timmer-Bonte, Anja N H ; van Steenhoven, Julia E C ; Hovenga, Sjoerd ; van Steenhoven, Julia E. C. ; Tetteroo, Geert W M ; van der Velden, Annette W. G.
AbstractBackgroundA previous prospective multicenter study revealed the change of the oncologists’ chemotherapy advice due to the 70-Gene signature (GS) test result in half of the estrogen receptor-positive (ER+) invasive early-stage breast cancer patients with disputable chemotherapy indication. This resulted in less patients receiving chemotherapy. This study aims to complement these results by the 7-year oncological outcomes according to the 70-GS test result and the oncologists’ pre-test advice.MethodsPatients operated for early-stage ER+ breast cancer with disputable chemotherapy indication, had been prospectively included between 2013 and 2015. Oncologists were asked whether they intended to administer adjuvant chemotherapy before deployment of the 70-GS test. Information on adjuvant systemic treatment and oncological outcome was obtained through active follow-up by data managers of the Netherlands Cancer Registry. The primary endpoint of this study was distant metastasis-free survival (DMFS) according to the genomic risk. Exploratory analyses were done to evaluate DMFS in relation to the oncologists’ pre-test advice.ResultsAfter a median follow-up of 7 years, distant metastases were diagnosed in 23 of the 606 patients (3.8%) and 36 (5.9%) patients had died. The DMFS rate for the 357 70-GS genomic low-risk patients was 94.2% (95% CI 91.2–96.2) and 89.1% for the 249 genomic high-risk patients (95% CI 84.3–92.4). Of the low-risk patients 3% had received chemotherapy compared to 80% of the high-risk patients. For the subgroups based on the pre-test oncologists’ advice (no chemotherapy/chemotherapy/unsure) there were no clinically relevant differences in DMFS (89.8, 93.2 and 92.0%, respectively), while comparable proportions of patients had received chemotherapy.ConclusionsIn patients with early-stage ER+ breast cancer with a disputable chemotherapy indication it is sensible to deploy the 70-GS to better select patients for adjuvant chemotherapy.
