[Radioiodine therapy for thyroid cancer]

Abstract

Radioiodine therapy is indicated in patients after total thyroidectomy for differentiated thyroid cancer, either as ablation of remnant thyroid tissue or to treat distant metastasis, most commonly to lung and bone. Surveillance after treatment includes thyroglobulin measurement, neck ultrasonography, chest CT, scintigraphy with radiothallium or diagnostic dose radioiodine, and possibly FDG-PET. Minor but frequent side effects involve organs with physiological iodine uptake, namely the salivary glands and stomach. Uncommon but serious ones are aggravation of spinal paralysis in cases with large vertebral metastasis and myelosuppression in those with extensive skeletal lesions. Despite clear therapeutic effects in some subjects, proving prolonged survival with this therapy in the group of patients with known metastasis as a whole is an elusive goal due to too good prognosis. One the other hand, a prospective analysis of a large case series did show beneficial effect of the radio-ablation. Empirical treatment is still debatable in subjects with elevated serum thyroglobulin level and negative whole body radioiodine scan. In the near future recombinant human TSH will obviate the need for intentional hypothyroidism in preparation for diagnostic scan and therapy with radioiodine.