OBJECTIVES: RET-fusions occur in ~10-20% of PTC patients, and RET-mutations in ~60% of MTC patients. RET-alteration testing can identify patients who could benefit from RET-targeted treatments, available through early-access in Taiwan at the time of this study. Consequently, this study describes RET-alteration testing, treatment and referral patterns for MTC and PTC patients in Taiwan.

METHODS: Data were drawn from the Adelphi Thyroid Cancer Disease Specific Programme™, a point-in-time survey of clinicians and their patients. Between July-September 2021, physicians in Taiwan abstracted medical records for their next 4 presenting advanced thyroid cancer patients, providing referral, testing and treatment pattern information.

RESULTS: Data were collected from 30 Taiwanese physicians, mostly haematologists/ medical oncologists (60%) and mostly practicing in private hospitals (57%). Physicians recruited 24 MTC and 133 PTC patients. Patients' median age was 55 (IQR:45-64.8) and 58 (IQR:49.5-68.5) years for MTC and PTC respectively.

Overall, 46% and 9% of MTC and PTC patients respectively were tested for RET-alteration, by single-gene testing or as part of multi-gene Next Generation Sequencing (NGS). Half of MTC patients were tested by Polymerase Chain Reaction, half by NGS. Most PTC patients underwent NGS testing (58%). 40% of MTC patients were RET-mutation-positive, whereas no PTC patients were RET-fusion-positive.

50% of MTC and 61% of PTC patients underwent surgery for advanced disease. 42% of MTC patients and 43% of PTC patients received first-line (1L) drug treatment. Of those, 50% of MTC patients received Sorafenib and 61% of PTC patients received Lenvatinib.

Endocrinologists were the predominant specialty involved at advanced stage diagnosis (58%/73% of MTC/PTC patients), whilst haematologists/ medical oncologists primarily were involved at 1L drug treatment (62%/59% of MTC/PTC patients).

CONCLUSIONS: Despite early access to RET-targeted treatments in Taiwan, RET-alteration testing was infrequent and could be improved to identify patients who could benefit from such treatments in future.