RADIOACTIVE IODINE TREATMENT AND EXTERNAL RADIOTHERAPY FOR LUNG AND BONE METASTASES FROM THYROID-CARCINOMA

We assessed the therapeutic benefits of I-131 treatment in patients wi th distant metastases of differentiated thyroid carcinoma. Methods: Of 2200 patients treated for differentiated thyroid carcinoma at our ins titution, 394 had lung and/or bone metastases. Results: Two-thirds of the patients had I-131 uptake in their metastases, but only 46% achiev ed a complete response. Prognostic factors for complete response were: younger age, presence of I-131 uptake in the metastases and small ext ent of disease. The survival rate was 33% at 15 yr. As shown by multiv ariate analysis, favorable prognostic factors for survival were: young er age and time of metastases detection, well-differentiated histologi c type of the thyroid tumor, presence of I-131 uptake in the metastase s, small extent of the disease and year of discovery of metastases. Co nclusion: In terms of survival, the benefits of I-131 therapy cannot b e demonstrated by prospective controlled studies. The present study cl early demonstrates, however, that treatment with I-131 is one of the f actors which accounts for survival; patients whose metastases concentr ated I-131 and who could be treated with radioiodine had higher surviv al rates. Patients who achieved complete response following treatment of distant metastases had a 15-yr survival rate of 89%, while those wh o did not achieve complete response had a survival rate of only 8%. Th e survival rate improved with the year of discovery of distant metasta ses, after I-131 total-body imaging and serum thyroglobulin measuremen ts were routinely used.