Real-world clinical profile, RET mutation testing, treatments, and PROs for MTC in Europe.

Objective: This study aimed to describe real-world patient and physician characteristics, rearranged during transfection (RET) mutation testing and results, treatment patterns, and patient-reported outcomes (PROs) in advanced or metastatic medullary thyroid cancer (aMTC) across five populous European countries.

Methods: Cross-sectional physician and patient surveys were used to collect quantitative and qualitative data in France, Germany, Italy, Spain, and the UK from July to December 2020, prior to the introduction of selective RET inhibitors in Europe. Physicians completed patient record forms and a survey about their specialty and practice site. Patients were asked to provide PRO data using four validated instruments, including the EuroQol 5 Dimension (EQ-5D) questionnaire.

Results: The physician-reported sample included 275 patients with aMTC, including 79 patients with RET mutation-positive disease; median age was 60 and 56 years, respectively. Overall, 75% were tested for RET mutation (35% germline only, 21% somatic only, 44% both). Common physician-cited barriers to RET mutation testing included high cost, difficulty accessing latest tests, and time delay for results. First-line systemic therapy (most commonly vandetanib or cabozantinib) was prescribed for 69% of patients overall and 82% of the RET mutation-positive subgroup. Second-line therapy was prescribed for 12% of patients who received first-line therapy; most patients remained on first-line therapy at data capture. PROs revealed substantial disease/treatment burden.

Conclusions: Patients with aMTC report substantial disease/treatment burden. Outcomes could be improved by identifying patients eligible for treatment with selective RET inhibitors through more optimal RET mutation testing.