Is above age 45 appropriate for upstaging well-differentiated papillary thyroid cancer?

Age greater than 45 years old is a prognostic marker in well-differentiated papillary thyroid cancer (PTC) using the American Joint Cancer Committee/Union Internationale Contre le Cancer Tumor Nodes Metastasis (AJCC/UICC TNM) staging system. Our clinical observation has been that patients aged 45 to 64 years have similar outcomes when compared to patients younger than 45 years, and we questioned the origin and accuracy of this prognostic variable.

Using SEERstat software, we analyzed the Surveillance, Epidemiology, and End Result (SEER) database for PTC using the following International Classification of Diseases for Oncology (ICD-O) codes: 8050, 8260, 8340, 8341, 8342, 8243, and 8344. Data were stratified in 5-year categories by age at diagnosis from 20 to 84 years old, with patients 85 years old and above categorized together. Survival is reported as cause specific.

A total of 53,581 patients were identified. The 5-year survival rate decreased with each increasing age category with no inflection point at age 45 in the survival curve. While the prognosis was less favorable in each advancing age group, survival remained above 90% for all age groups under 65 years.

A review of the literature reveals a lack of data supporting the use of age 45 as a prognostic variable. Our SEER database review revealed a continuum of disease-specific mortality for each incremental 5-year time period above age 45. We conclude that the current use of age 45 as a single prognostic age marker does not accurately reflect the progressive mortality risk that is apparent with each 5-year increment in age.