(ChemotherapyAdvisor) – Adjuvant radioactive iodine for the treatment of patients with papillary thyroid cancer should be considered on a case-by-case basis by a multidisciplinary team experienced in managing the disease, investigators reported during the 82nd Annual Meeting of the American Thyroid Association (ATA) in Québec City, Québec, Canada, on September 20.

Currently, the ATA guidelines recommend routine use of radioactive iodine in all T3 or greater primary tumors and selective use in patients with intrathyroidal disease <1 cm or evidence of nodal metastases, noted Iain J. Nixon, MD, and colleagues from Memorial Sloan-Kettering Cancer Center (MSKCC), New York, NY. “The guidelines recognize that there are conflicting and inadequate data to make firm recommendations for most patients.”

To analyze MSKCC’s experience with the selective use of radioactive iodine in the management of well-differentiated thyroid cancer, the investigators retrospectively reviewed data on 1,129 patients who underwent total thyroidectomy between 1986 and 2005. Median age was 46 years (range 11-91 years) and nearly three times as many women as men were treated. None had evidence of macroscopic residual disease after surgery or distant metastases; 490 patients were pT1/T2N0; 193, pT1/T2N1; and 444, pT3/T4. “All patients were assessed using the GAMES risk stratification method,” Dr. Nixon reported, and “select patients within each group did not receive radioactive iodine.”

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At a median follow-up of 63 months (range 1-282 months), select patients with early primary disease (pT1/T2) and low-volume metastatic disease in the neck (pT1/T2 N1) managed without radioactive iodine were found to have “excellent outcomes,” he noted. In those with advanced local disease (pT3/T4), select patients with pT3N0 disease “were safely managed without radioactive iodine.”

The 5-year disease-free survival in the pT1/T2N0, pT1/T2N1, and pT3/T4 groups were 100%, 100%, and 92%, respectively, and relapse-free survival was 92%, 92%, and 87%.

“Our results justify the selective use of radioactive iodine following initial surgical treatment using a risk group stratification method,” he stated. “The place of radioactive iodine in the management of papillary thyroid cancer should not be a blanket treatment for all.”