Radioiodine treatment of metastatic thyroid carcinoma: the Royal Marsden Hospital experience

The case records of 235 patients who were treated for differentiated thyroid cancer between 1949 and 1981 were reviewed. Forty-two (18%) had distant metastatic spread outside the neck and received radioiodine (¹³¹I) therapy. In cases where the distant spread was confined to the lungs, 54% of patients were alive, free of disease, 10 years after ¹³¹I treatment was started. By contrast, no patient with skeletal involvement has survived for 10 years and only one for five years after treatment. A variety of cytotoxic drugs has been tried on an ad hoc basis with no notable success. One patient developed preleukaemia three months after completion of ¹³¹I treatment, but no other serious side effects were observed. Factors that influence the behaviour of metastatic thyroid carcinoma are discussed and a possible revised approach to ¹³¹I therapy is suggested in the light of these findings.