MORBIDITY AND MORTALITY IN FOLLICULAR THYROID-CANCER

The natural history and results of treatment have been analyzed in a g roup of 49 patients with follicular thyroid carcinoma who were followe d for an average of 10.7 yr. Striking differences between the course o f follicular thyroid carcinoma and the course of papillary carcinoma a re evident. Deaths from cancer were double (16% for follicular), age a t diagnosis was older, and age at death was younger. All deaths and re currences happened within 13 yr, in contrast to the continued experien ce of deaths and recurrences in papillary cancer, even through 40 yr o f observation. Adverse outcome correlated with extent of disease at di agnosis and with size of primary tumor, but did not correlate with ves sel invasion, extent of capsule invasion, degree of dedifferentiation, extent of primary surgery, or radioactive iodide ablation. These obse rvations are again in striking contrast to experience with papillary c ancer. No patient with intrathyroidal disease who was under age 45 at diagnosis and with a primary tumor of less than 2.5 cm died. Our obser vations suggest that follicular cancer, even if apparently intrathyroi dal, carries a high mortality rate in patients over,age 45 or in those with tumors larger than 2.5 cm at the time of diagnosis and suggest t hat we must consider additional therapeutic measures in this group of patients, including larger radioiodine doses for initial therapy, exte rnal radiotherapy, and even possibly prophylactic chemotherapy.