Prospects for Personalised Treatment of Patients with Radioiodine-avid Locally Recurrent or Metastatic Thyroid Cancer

Although most patients with metastatic or inoperable locally recurrent differentiated thyroid cancer have radioiodine-avid disease, the outcome for patients who do not achieve remission with radioiodine therapy is poor. Most centres use fixed empirical activities of radioiodine to treat these patients, which is in contrast to other areas of oncology, where there is a shift to more individualised treatment. The use of dosimetry techniques to calculate a more appropriate activity of radioiodine for each patient may increase the effectiveness of radioiodine therapy but is more complex, time-consuming and of unproven benefit. This review addresses some of the limitations of empirical radioiodine therapy, discusses existing dosimetry-based approaches to individualising therapy and proposes further work in this area. A prospective randomised controlled trial comparing empirical activities of radioiodine with activities guided by a combination of lesional dosimetry and maximum safe dose has not been carried out previously. Although considerable challenges in the design of such a study remain, a network of centres in the UK now has the potential to take this forward.