Therapeutic Drug Monitoring-Guided Adjuvant Tamoxifen Dosing in Patients with Early Breast Cancer: A Cost-Effectiveness Analysis from the Prospective TOTAM Trial

Abstract

Background and Objectives Endoxifen is the active metabolite of tamoxifen, and a minimal plasma concentration of 16 nM has been suggested as a threshold above which it is effective in reducing the risk of breast cancer recurrence. The aim of the current analysis was to investigate the cost-effectiveness of therapeutic drug monitoring (TDM)-guided tamoxifen dosing. Methods A cost-effectiveness analysis was performed from a Dutch healthcare perspective, using a partitioned survival model and a lifetime horizon. The reduction in subtherapeutic treatment following TDM is modelled as improved rates of recurrence-free survival (RFS) and overall survival (OS) in comparison to standard tamoxifen treatment. A probabilistic sensitivity analysis (PSA) and a series of scenario analyses were performed to assess the robustness of the results. Results Base-case results estimated a total increase in life years and quality-adjusted life years (QALYs) for TDM of 0.40 and 0.53, respectively. Total costs for TDM and standard tamoxifen treatment are €32,893 and €39,524, respectively. The TDM intervention results in both more QALYs and less healthcare costs, indicating a dominating effect for TDM. The PSA results indicate that the probability of TDM being cost-effective is 92% when using a willingness-to-pay threshold of €20,000. Conclusions TDM-guided dose optimization of tamoxifen is estimated to save costs and increase QALYs for early breast cancer patients.

Cost-Effectiveness Analysis of MammaPrint® to Guide the Use of Endocrine Therapy in Patients with Early-Stage Breast Cancer

“… n.a. Patient and family costs Per cycle SE Alpha Beta Source Travel costs Patients with minor AEs €4.64 €0.46 a 100 0.05 [ 17 ] Informal care costs Patients who died from major AEs €2680 €670 b 16 168 [ 52 ] Costs made in other sectors Per cycle SE Alpha Beta Source Costs due to productivity losses for patients treated with ET with related AEs —first 3 months €3094 €656 22 139 TOTAM study (see Supplemental file 7) [ 28 , 29 ] Costs due to productivity losses for patients treated with ET-related AEs —next 3 months €907 €348 7 133 Costs due to productivity losses for patients treated with ET-related AEs —subsequent months €846 €342 6 138 Costs due to productivity losses for patients without ET-related AEs —first 3 months €320 …”

“…Dis-utilities were also applied for patients who experienced any minor AE. These dis-utilities were calculated based on patient-level data from the Therapeutic Drug Monitoring Of TAMoxifen (TOTAM) study (Dutch Trial Registry; NL6918) (Supplemental file 5, see ESM) [ 28 , 29 ]. This study evaluated therapeutic drug monitoring-guided dosing of adjuvant tamoxifen and collected data on adverse events, quality of life (EQ5D-5L) and productivity losses (Institute for Medical Technology Assessment [iMTA] Productivity Cost Questionnaire [PCQ]) 3, 6 and 24 months post-initiation of tamoxifen [ 30 ].…”

“…Travel costs were calculated by multiplying the average distance to the health care facility with the average travel costs per kilometer (Dutch costing manual) [ 17 ]. Productivity losses related to experiencing minor AEs were calculated based on patient-level data of patients in the TOTAM study (see Supplemental file 7 in the ESM for more information) [ 28 , 29 ]. Costs of productivity losses were applied for 15 cycles because the average age of women in our model was 63.3 years and the retirement age in the Netherlands is 67 years in 2024 [ 31 ].…”

Cost-effectiveness of Tamoxifen versus Anastrozole in post-menopausal women with breast cancer: Saudi Arabia perspective

“…The characteristics of the cohort are similar to the patients included in the Braal L. et al study. [9] Patients included in the model are early postmenopausal, diagnosed with locally advanced estrogen-receptorpositive breast cancer with no contraindications for both comparators (Tamoxifen and Anastrozole). Women are considered in the menopause state if they fulfill one or more of the criteria of the National Comprehensive Cancer Network (NCCN) [10] definition of menopause.…”