The incidence of thyroid cancer has increased by 250% in the last 20 years. The use of radioactive iodine therapy for thyroid cancer has declined in recent years, but a quarter of patients still receive this unnecessary treatment, according to research published in the journal JAMA Internal Medicine. Dr. Roman, a professor of surgery at Duke University School of Medicine, said papillary microscopic thyroid cancers (PTMCs) account for the largest proportion of new cases, and the study underscores the fact that a large proportion of such patients receive unnecessary radioactive iodine therapy. The use of radioactive iodine in the treatment of thyroid cancer is controversial. Adjuvant radioactive iodine therapy is commonly used to treat differentiated thyroid cancer to remove incompletely removed thyroid tissue, reduce the risk of recurrence, and have a therapeutic effect on residual disease. However, some experts question the appropriateness of radioactive iodine therapy for thyroid cancer that has been surgically treated, and some even consider radioactive iodine therapy to be overtreatment because there is no evidence of benefit for low-risk thyroid cancer. Modern guidelines also do not recommend adjuvant radioiodine therapy for medullary thyroid cancer, undifferentiated thyroid cancer, or PTMC. radioiodine therapy is expensive and has many comorbidities, including radiation therapy-induced malignancy. Because thyroid cancer affects young people, these effects can last a lifetime. Dr. Roman and colleagues identified patients with undifferentiated thyroid cancer, patients with medullary thyroid cancer, and patients with PTMC through the National Cancer Database for the time period 1998-2011. the authors also cross-checked through the SEER database and assessed the cost of PTMC against the Medicare claims database. Patients with PTMC ≤1 cm were included in the study and should have non-invasive histology, no regional or distant metastases, negative cut margins, and the tumor should not extend beyond the thyroid gland. Radioiodine therapy was administered to 1.6% of 3095 undifferentiated thyroid cancers, 3.4% of 6375 patients with medullary thyroid cancer, and 23.3% of 60586 patients with PTMC at an average cost of $5429-$9105. Factors associated with inappropriate radioiodine therapy in a corrected analysis included: Hispanic origin The factors associated with inappropriate radioiodine treatment included: Hispanic origin, low income, non-academic treatment setting, tumor multiplicity, and larger tumors. Patients with PTMC who received radioactive iodine treatment tended to be younger, treated in non-academic medical centers, and had more frequent and/or larger tumors. PTMC patients were nearly two times more likely to receive inappropriate radioiodine treatment at a non-academic center than at an academic center. Time-trend analysis shows that inappropriate radioiodine treatment rates do not change over time in community-based programs, but do decrease in academic programs. These results imply that practice patterns in non-academic communities or medical centers change slowly, even in the face of emerging data and constant updating of guidelines, Roman explained, adding that these results suggest that specific subgroups of patients vulnerable to inappropriate treatment may be health care workers or institutions that have less access to constant updates in medical practice. Roman emphasized the study’s focus on better dissemination of national medical practice guidelines among all health providers and centers, especially in areas with high concentrations of susceptible individuals. Dr. Haymart, of the University of Michigan Medical School, said the study is important because it identifies the types of people who will be treated with unnecessary radioactive iodine therapy, and it confirms changes in thyroid cancer treatment that are more aggressive than the treatment recommended in current guidelines. Dr. Haymart and his colleagues have found significant increases and variations in the use of radioactive iodine therapy in previous studies, which means that clearer and more understandable guidelines are needed to clarify how radioactive iodine therapy should be used. Some patients with well-differentiated, high-risk thyroid cancer can benefit from radioiodine therapy, he told Medscape Medical News. Recent literature and clinical guidelines do not support the use of radioiodine therapy for low-risk PTMC, and both patients and physicians need to be educated to improve thyroid cancer treatment, including the fact that low-risk PTMC should be treated less frequently with radioiodine therapy, while medullary thyroid cancer and undifferentiated thyroid cancer do not require radioiodine therapy. Radiation iodine therapy is not required.