Clinically meaningful end points in the evolving treatment paradigm for radioactive iodine-refractory differentiated...

Radioactive iodine (RAI) is often used post-operatively for treatment of differentiated thyroid cancer (DTC), but many patients develop RAI-refractory disease. Patients with RAI-refractory DTC may be asymptomatic and stable for long periods of time, so identifying tumors that are no longer likely to respond to RAI treatment and determining when to transition to systemic therapy are critical issues for optimal patient care. The purpose of this paper is to review and assess the end points used in studies of RAI-refractory DTC in relation to the issues facing clinicians in transitioning patients to systemic therapy. Our goals are to provide a framework to help evaluate whether study results are clinically meaningful in guiding treatment decisions and to make recommendations to better define these end points for RAI-refractory DTC.