Abstract
PurposeWe assessed the recent trends in the administration of adjuvant chemotherapy thereby evaluating the role of the 70-gene signature (70-GS) testing in decision-making in the systemic treatment of patients with lymph node negative (N0) and lymph node positive (N+) breast cancer.MethodsPatients with a national guideline directed indication for 70-GS use treated between 2013 and 2016 were selected from the Netherlands Cancer Registry. Time trends in the administration of adjuvant chemotherapy were evaluated within guideline- and age-delineated subgroups. The influence of the 70-GS on chemotherapy use was assessed with logistic regression.ResultsDuring the study period, the overall administration of adjuvant chemotherapy decreased from 49 to 23% and 70-GS use increased from 24 to 51%. The 70-GS was not associated with a decreased likelihood for N0 patients to receive chemotherapy (odds ratio [OR] 1.0; 95% confidence interval [CI] 0.86–1.17), as the proportion of N0 patients who received chemotherapy in the absence of 70-GS use decreased during the study period. In patients with N1a disease, 70-GS testing was associated with a decreased likelihood to receive chemotherapy (OR 0.21; 95% CI 0.15–0.29). In patients < 50 years and 50–59 years of age, 70-GS use was associated with a consistent lower proportion of patients receiving chemotherapy throughout the study period (OR 0.17; 95% CI 0.13–0.23 and OR 0.53; 95% CI 0.43–0.65, respectively).ConclusionsIn this population-based study, the administration of adjuvant chemotherapy in ER+ breast cancer strongly declined. For node-positive and younger patients, 70-GS use was associated with a decreased probability for patients to receive adjuvant chemotherapy.
Highlights
70-gene signature (70-GS) use decreased during the study period
In a previous nationwide study, we demonstrated that the use of the 70-GS was associated with a significant reduction of chemotherapy administration in the subset of estrogen receptor (ER)?/Her2- disease without overt lymph-node metastasis (B Nmi) treated between 2011 and 2013.14 Recent randomized trials studying the contribution of Gene-expression profiles (GEPs) to the decision to administer adjuvant chemotherapy suggest a role for GEPs in lymph node-positive patients.[8,15]
We describe the time trends in chemotherapy use in a large population-based cohort of ER?/Her2- breast cancer patients considered eligible for GEP use according to national guidelines, encompassing the period of time since the Dutch breast cancer guideline first suggested a role for GEP use until the period that the results of the GEP trials were available
Summary
70-GS use decreased during the study period. In patients with N1a disease, 70-GS testing was associated with a decreased likelihood to receive chemotherapy (OR 0.21; 95% CI 0.15–0.29). For node-positive and younger patients, 70-GS use was associated with a decreased probability for patients to receive adjuvant chemotherapy. In a previous nationwide study, we demonstrated that the use of the 70-GS was associated with a significant reduction of chemotherapy administration in the subset of ER?/Her2- disease without overt lymph-node metastasis (B Nmi) treated between 2011 and 2013.14 Recent randomized trials studying the contribution of GEPs to the decision to administer adjuvant chemotherapy suggest a role for GEPs in lymph node-positive patients.[8,15]. We describe the time trends in chemotherapy use in a large population-based cohort of ER?/Her2- breast cancer patients considered eligible for GEP use according to national guidelines, encompassing the period of time since the Dutch breast cancer guideline first suggested a role for GEP use until the period that the results of the GEP trials were available. The use and impact of the 70-GS on chemotherapy administration was evaluated in different subgroups delineated by lymph node status, grade, tumor size, and age
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