The primary objective of this registry/repository is to store ongoing clinical data and biospecimens to facilitate the conduct of research on disorders of growth, genetic, and epigenetic alterations. This can also include storage of samples and data from relatives of the index patients to serve as study controls.

This study involves taking a study drug called selpercatinib. The overall goal of this study is to find out how effective the study drug is in combination with radioactive iodine (I-131) in treating people with thyroid cancer. The study drug will be given in combination with treatments you will receive as part of your regular cancer care (I-131 and thyrotropin alfa).