Prolongation of tumour volume doubling time (midDT) is associated with improvement in disease-specific survival in patients with rapidly progressive radioactive iodine refractory differentiated thyroid cancer selected for molecular targeted therapy.

Lung midDT is a useful and important clinical marker of disease-specific survival for patients with progressive radioactive iodine refractory (RAIR) metastatic thyroid cancer. In patients with rapidly progressive metastatic RAIR thyroid cancer, molecular targeted therapy prolongs lung tumour volume doubling time and is associated with improved disease-specific survival.