DIFFERENTIATED THYROID-CANCER - REEXAMINATION OF RISK GROUPS AND OUTCOME OF TREATMENT

Objective: To reexamine the age, metastases, extent, and size (AMES) r isk criteria for well-differentiated thyroid cancer with the effect of therapy on outcome. Design: Review of patient medical records and dir ect-contact follow-up. Setting: Two tertiary referral centers. Main Ou tcome Measures: Recurrence or death. Patients: One thousand nineteen p atients with well-differentiated thyroid cancer treated between 1940 a nd 1990. Results: One thousand nineteen patients with well-differentia ted thyroid cancer were treated between 1940 and 1990, with a mean fol low-up of 13 years, including a recent group of 264 patients treated f rom 1980 to 1990 at 2 different institutions with a mean follow-up of 8 years. The AMES criteria were used to designate high-and low-risk pa tients. The entire group had 229 high-and 790 low-risk patients; the p ercentage of high-risk patients de creased slightly after 1960. From 1 940 to 1960, 1960 to 1979, and 1980 to 1990, the high-risk groups had survival rates of 48%, 62%, and 47%, respectively. For the low-risk pa tients, survival rates were 96%, 98%, and 98%, respectively. Recurrenc es occurred in 5% of low-risk patients and were usually curable; in hi gh-risk patients, recurrence was associated with a 75% mortality. In l ow-risk patients, there was no significant difference in recurrence or death according to type of operation (unilateral or bilateral) or use of radioactive iodine. In high-risk patients, there were trends towar d but no significant improvement in survival with bilateral sugery and radioactive iodine therapy; thyroid replacement was associated with a significant improvement in survival. Conclusions: The AMES risk crite ria remain highly valid predictors of risk. They define most low-risk patients for whom radical treatment may add excess morbidity but not i mprove already excellent prognoses.