Updated American Joint Committee on Cancer/Tumor-Node-Metastasis Staging System for Differentiated and Anaplastic Thyroid Cancer (Eighth Edition): What Changed and Why?

Age is a critical factor in outcome for patients with well-differentiated thyroid cancer. Currently, age 45 years is used as a cutoff in staging, although there is increasing evidence to suggest this may be too low. The aim of this study was to assess the potential for changing the cut point for the American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) staging system from 45 years to 55 years based on a combined international patient cohort supplied by individual institutions. Show more

In most staging systems, 45 years of age is used to differentiate low risk thyroid cancer from high risk thyroid cancer. However, recent studies have questioned both the precise 45 year age point and the concept of using a binary cut off as accurate predictors of disease specific mortality.

Differentiated thyroid carcinoma (DTC) generally has a good prognosis. As yet, however, it is unclear whether life expectancy is reduced in these patients and, if so, to what extent. The aim of this study was to determine how the all-cause mortality rate in DTC patients compares to that of the general population. A prospective database study was conducted. The study included 2011 DTC patients treated in our hospital from 1980-2011. All patients received total thyroidectomy with subsequent (131)I ablation, except for those with an isolated papillary microcarcinoma. Survival data for the general German population were obtained from the German Federal Statistics Agency and matched to our DTC population for age and sex. Patients who were at least 45 yr old at diagnosis and had extensive perithyroidal invasion (UICC/AJCC TNM system, 7th edition, stages IVa and IVb), lateral cervical lymph node metastases (TNM stage IVa), or distant metastases (TNM stage IVc) showed a clearly reduced life expectancy [relative cumulative survival rate (observed:expected) for stage IVc after 20 yr, 0.295; 95% confidence interval, 0.033-0.556]. In patients over 60 yr of age at diagnosis, the loss of life expectancy was (much) greater than for those aged 45-59 yr in all groups. Life expectancy was not reduced in patients with TNM stages I, II, or III (86% of patients). Life expectancy is not significantly reduced in 86% of DTC patients; only patients at least 45 yr old with extensive local invasion, lateral lymph node metastases, and/or distant metastases (TNM stages IVa, IVb, and IVc) at diagnosis showed a clearly lower life expectancy. Show more