Past:
Differentiated thyroid cancer (DTC) patients require lifelong surveillance secondary to excellent survival after treatment, making recurrence an impactful outcome to measure.1 The American Joint Commission on Cancer’s (AJCC) Tumor, Nodes, Metastasis staging system is universally known but stratifies based on risk of cancer mortality, not recurrence.2–4 Other risk stratification systems for DTC exist but are not built into the standard staging system, nor are they in such widespread use. We hoped to define the risk of recurrence by stage using the new AJCC 8th edition.5
Present:
In the new AJCC staging system, nearly all patients considered disease free after treatment have stage I or II disease (99% in the study5). As a result, the 8th edition is able to better differentiate risk of recurrence between stage I and II patients (3.2% and 15.9% at 10 years, respectively). While the increased risk of recurrence in stage II patients likely reflects the substantial downstaging of patients in the 8th edition, there are important implications for the AJCC staging system. First, because all thyroid cancers are staged, clinicians can broadly estimate risk of recurrence based on the given stage without knowing the more granular, and often unavailable clinicopathological factors. Second, clinicians can tailor their treatment or follow-up to the overall stage knowing that stage according to the AJCC 8th edition correlates with outcomes.
Future:
The AJCC 8th edition has made significant strides in survival prediction and recurrence prediction. However, the search for the ideal prognostic model remains. The 8th edition encourages the use of clinicopathological factors in addition to the model itself to aid in recurrence prediction.4 Future models will need to include additional relevant clinicopathological factors to complement the stage to accurately predict the risk of recurrence in DTC. The ideal model would tailor treatment and surveillance regimens based on the risk of recurrence at a global level.
Footnotes
Publisher's Disclaimer: This Author Accepted Manuscript s a PDF file of an unedited peer-reviewed manuscript that has been accepted for publication but has not been copyedited or corrected. The official version of record that is published in the journal is kept up to date and so may therefore differ from this version.
ASO Author Reflections is a brief invited commentary on the article, “Risk of Recurrence in Differentiated Thyroid Cancer: A Population-Based Comparison of the 7th and 8th Editions of the American Joint Committee on Cancer Staging Systems,” Ann Surg Oncol. (2019). https://doi.org/10.1245/s10434-019-07275-1
Disclosures: The authors have no conflicts of interest to disclose.
References
- 1.Ge MH, Cao J, Wang JY, et al. Nomograms predicting disease-specific regional recurrence and distant recurrence of papillary thyroid carcinoma following partial or total thyroidectomy. Medicine (Baltimore). 2017;96(30):e7575. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Cooper DS, Doherty GM, Haugen BR, et al. Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer. Thyroid. 2009;19(11):1167–1214. [DOI] [PubMed] [Google Scholar]
- 3.Pontius LN, Oyekunle TO, Thomas SM, Stang MT, Scheri RP, Roman SA, Sosa JA. Projecting Survival in Papillary Thyroid Cancer: A Comparison of the Seventh and Eighth Editions of the American Joint Commission on Cancer/Union for International Cancer Control Staging Systems in Two Contemporary National Patient Cohorts. Thyroid. 2017;27(11):1408–1416. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Tuttle RM, Haugen B, Perrier ND. Updated American Joint Committee on Cancer/Tumor-Node-Metastasis Staging System for Differentiated and Anaplastic Thyroid Cancer (Eighth Edition): What Changed and Why? Thyroid. 2017;27(6):751–756. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Gan T, Huang B, Chen Q et al. Risk of recurrence in differentiated thyroid cancer: a population-based comparison of the 7th and 8th editions of the American Joint Committee on Cancer staging systems. Ann Surg Oncol. (2019). 10.1245/s10434-019-07275-1 [DOI] [PMC free article] [PubMed] [Google Scholar]