Study results presented by Guerrero and colleagues at the 21st Annual Congress of the American Association of Clinical Endocrinologists showed that where a patient lives when he or she is diagnosed with thyroid cancer can have an effect on the stage at which the cancer is diagnosed and on cancer-free survival (CFS) rates.
Using information from the Surveillance Epidemiology and End Results (SEER) database, the authors identified more than 87,000 individuals diagnosed with thyroid cancer between 1973 and 2008, assessing for historical stage of diagnosis and CFS according to geographic region. The data were stratified by thyroid cancer type, race/ethnicity of the patient, age, year of diagnosis, and registry site. Data were excluded for Hawaii and Alaska natives, patients with cancer stage 0 or unknown stage at diagnosis, patients who had been previously diagnosed with tumors, patients whose age was unknown at diagnosis, and patients for whom survival information was missing.
The four geographic regions for this study were: West (including data from San Francisco-Oakland, New Mexico, Seattle, Utah, San Jose, Los Angeles, and other locales), South (Atlanta and rural Georgia, Kentucky, and Louisiana), East (Connecticut and New Jersey), and Midwest (Detroit and Iowa). Fifty-five percent of individuals analyzed were from the West, 12% were from the South, 18% were from the East, and 15% were from the Midwest.
The authors reported that 60% of patients presented with localized disease, 34% with regional metastasis, and 5.6% with distant metastasis. Papillary thyroid cancer was the most prevalent diagnosis across regions and ethnicities (West: 85%, South: 82%, East: 83%, Midwest: 79%), followed by follicular thyroid cancer (West: 7.3%, South: 9%, East: 7.7%, Midwest: 10.7%). Median age at diagnosis was consistent across regions (roughly 46-48 years of age).
Regional differences in thyroid cancer stage and survival included:
Patients in the West region had a higher risk of presenting with regional and distant metastases
Patients in the South had lower CFS
Patients in the East with follicular cancer were more likely to have local disease
The large majority of patients in this study were female (at least 75% of the patient population in each region) and non-Hispanic white (66-87% of the population in each region, with the highest concentration in the South and Midwest). The authors reported “no significant difference in CFS by geographic region for non-Hispanic white or Hispanic white individuals,” but did find that “blacks from the West had significantly better CFS than blacks from the South.”
The authors concluded that “there are differences in the stage of presentation and survival of individuals with thyroid cancer according to geographic region.” They identified socioeconomic factors, access to healthcare, and cultural beliefs as potential contributing factors.
The data in this study were also used to determine “if there were any differences in treatment before and after the publication of the 2006 American Thyroid Association management guidelines for thyroid nodules and thyroid cancer.” The authors determined that “more patients received a sub-total, near-total, or total thyroidectomy, and more patients had lymph node dissections” after publication of the guidelines. They reported that “stage of presentation and use of radioactive iodine ablation did not change” after the guidelines were published.