Selective use of radioactive iodine in intermediate-risk papillary thyroid cancer

OBJECTIVE To describe the outcomes with the selective use of radioactive iodine (RAI) in patients who are at intermediate risk of death from papillary thyroid cancer, focusing on 2 subgroups: patients older than 45 years with low-risk tumors and patients younger than 45 years with high-risk tumors. DESIGN Retrospective case review. SETTING Tertiary referral US cancer center. PATIENTS The study incluced 532 consecutive patients who were surgically treated between 1986 and 2005. INTERVENTIONS All patients underwent total thyroidectomy; 307 also received RAI. MAIN OUTCOME MEASURES Disease-specific survival (DSS) and recurrence-free survival (RFS). RESULTS Of 344 patients older than 45 years with low-risk tumors, 148 (43%) received RAI and 196 (57%) were selected not to receive RAI. The patients who were treated without RAI were more likely to be female and have pT1N0 disease. The 5-year DSS and RFS were 100% and 98%, respectively. The presence of nodal metastases predicted poorer 5-year RFS within this group (99% vs 91%; P = .004). Of 188 patients younger than 45 years with high-risk tumors, 159 (85%) received RAI, and only 29 (15%) were selected not to receive RAI. The 5-year DSS and RFS for these patients were 100% and 95%, respectively. The presence of nodal metastases predicted poorer 5-year RFS within this group (100% vs 86%; P = .02). CONCLUSION Our study shows that the subgroup of patients who are older than 45 years with tumors that are smaller than 4 cm in greatest dimension and confined to the thyroid gland and who do not have nodal metastases can safely be treated without RAI.