Eliminating the Age Cutoff in Staging of Differentiated Thyroid Cancer: The Safest Road?

Abstract Background Unlike virtually all other cancer types, thyroid cancer is unique in that patient age is a key component in its staging. Pathologists and clinicians worldwide have accepted an age cutoff of 45 years for staging; in 2018, this advances to age 55 years in the eighth edition of the American Joint Commission on Cancer staging system. Evidence Acquisition Clinical and basic research studies, reviews, and previous editions of consensus statements regarding thyroid cancer staging were reviewed, with particular focus on the influence of age in thyroid cancer prognosis. Purpose This perspective briefly reviews the basis for this practice and challenges it as no more appropriate than for other malignancies. Evidence Synthesis The majority of findings report an association of age with thyroid cancer survival but do not support a specific age cutoff; rather, they suggest that outcome is affected by age as a continuous variable. Conceivably, other factors interact with age on a continuous basis over time, affecting prognosis. When identified, these factors could alter our current concept of the importance of an age cutoff in staging. Conclusions Among all cancers, age has an important role in only thyroid cancer staging. The consideration of age as a continuous variable and the search for age-associated prognostic variables could elucidate a more accurate staging system. In their Perspective article, the authors challenge the practice of incorporating an age cutoff as a key component of AJCC staging of differentiated thyroid cancer.