Impact of reimbursement on the utilization of gene expression profiles and chemotherapy in Dutch breast cancer patients.

Introduction: Gene expression profiles (GEPs) have emerged as supportive tests in refining breast cancer treatment decisions regarding chemotherapy. This study investigated the reimbursement of MammaPrint and Oncotype DX, the impact on usage and chemotherapy decisions, and the factors influencing the odds of undergoing a GEP test. Methods: Invasive non-metastatic breast cancer patients aged ≥18 years and treated surgically between 2011 and 2023 were selected from the Netherlands Cancer Registry. GEP test utilization among different patient groups, whether eligible for reimbursement or guidelines, was presented in a flowchart, categorizing patients by MammaPrint, Oncotype DX, or no test and further dividing them based on chemotherapy received. Further analyses were conducted exclusively on patients eligible for reimbursement. For the descriptive analyses, percentages were presented separately regarding GEP test usage in associations with chemotherapy, trends from 2011 to 2023, and the utilization across different regions. The GEP test utilization trends and regional transitions were assessed. The Chi-squared test was applied to compare test types and reimbursement periods across regions (p <0.05). Additionally, logistic regression analyses were conducted to show which factors influence GEP test use. First, the univariable analysis was conducted (p <0.1), followed by the multivariable analysis (p <0.05), which included the significant variables from the univariable analysis. Results: Of all patients included (n=173,022), 8% received a GEP test, with 36% of them undergoing chemotherapy and 64% not. In the no GEP test group, 38% received chemotherapy, while 62% did not. Among the patients eligible for reimbursement (n=17,836), 17% received a GEP test. Those who received a GEP test tended to get more adjuvant chemotherapy (32%) and less neoadjuvant chemotherapy (3%) compared to those without a GEP test (23% and 9%, respectively). When Oncotype DX was reimbursed in 2021, a significant shift was observed between 2021 and 2022 from using MammaPrint to Oncotype DX across all regions. Oncotype DX was increasingly used from 2022 onward, while the use of MammaPrint declined. The Chi-squared test results showed significant associations (p <0.05) in each region between the type of test and the reimbursement periods from 2011 to 2023. Additionally, there was a significant relationship between the utilization of GEP tests and the reimbursement of these tests. The reimbursement periods had higher odds of receiving a GEP test. The odds of undergoing a GEP test in relation to the reimbursement periods were corrected by factors such as age at diagnosis, tumor size, lymph node involvement, geographic region, and tumor grade. When both MammaPrint and Oncotype DX were reimbursed, the odds of receiving a GEP was highest (odds ratio: 5.59, 95% CI 3.7 to 8.5). Conclusion: In the Netherlands, next to patient and tumor characteristics, reimbursement periods significantly influenced the use of a GEP test. The reimbursement of Oncotype DX led to a shift from MammaPrint to Oncotype DX across several regions in the Netherlands between 2021 and 2022. Inconsistent policies about reimbursement had led to potential inequities, emphasizing the need for standardized, clear reimbursement policies to ensure fair access to GEP testing.