Aim: To describe real-world testing patterns for RET in US patients with advanced/metastatic medullary thyroid cancer and determine consistency of real-world testing practices with national guidelines. Materials & methods: The authors performed a retrospective medical record analysis of patients with advanced/metastatic medullary thyroid cancer who initiated systemic therapy between 2013 and 2018. Seventy-five US-based oncologists collected the data using a customized electronic data collection form. Results: A total of 59.6% (121 of 203) of patients underwent testing for RET, and 37.2% (45 of 121) had a RET mutation, of which 55.6% were identified as RET mutation-positive before initial diagnosis. Overall, 90 (44.3%) patients were tested for biomarkers on or after initial diagnosis, with RET being the most tested (95.6%) biomarker. Conclusion: The authors' findings suggest an opportunity to improve testing rates in accordance with treatment guidelines.
Keywords: RET; advanced diagnosis; biomarker testing; genetic testing; initial diagnosis; medical record data; medullary thyroid cancer; retrospective; sample type; time of test.
Mutations in the RET gene are common in patients with medullary thyroid cancer (MTC). As RET mutations are involved in the development of MTC, several treatment guidelines recommend counseling patients and testing for mutations in the RET gene in all patients with MTC. However, limited data are available on RET testing patterns in the USA in this patient population. In this study, the authors determined testing patterns for RET in patients with advanced or metastatic MTC in the USA using real-world data and found that only 60% of patients were tested for RET (i.e., testing for presence of RET mutations was observed in less than two-thirds of all patients included in the study). These results demonstrate the need for improved testing for RET mutations in patients with MTC in alignment with the treatment guidelines in routine clinical practice in the USA.