Therapeutic Drug Monitoring guided tamoxifen dosing: a feasibility study in patients with hormone positive breast cancer

Project summary

Adjuvant treatment with tamoxifen significantly reduces the chance of recurrence. Despite the adjuvant endocrine treatment, in some patients the disease returns within five years. Literature indicates that there is a minimal endoxifen concentration of 16 nmol/L to produce a therapeutic effect. In this exploratory study we will therefore evaluate the impact of TDM guided dosing on endoxifen levels in patients treated with tamoxifen