OP66 – Reassessment of Differentiated Thyroid Cancer Patients Using the 8th TNM classification System: a comparative study

•   Benbassat, Carlos^1,3_; Muallem Kalmovich, Limor^2,3; Steinschneider, Miriam^1,3; Koren, Shlomit^1,3; Or, Karen¹ ; Cantrell, Dror¹ 1 Endocrine Institute, Assaf Harofeh Medical Center, Zerifin, Israel 2 Head and Neck Surgery Unit, Department of ENT, Assaf Harofeh Medical Center, Zerifin, Israel 3 Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel   Background: Based on the prevailing concept that over-diagnosis with no change in mortality drives the increased incidence of differentiated thyroid cancer (DTC), considerable modifications have been introduced in the new TNM staging edition. Aims: We aimed to compare a same group of DTC patients before and after re-staging for mortality, disease severity and disease outcome. Methods: From our thyroid cancer registry, 431 DTC patients were re-staged according to the 8th edition and compared to the 7th for clinico-pathological data, treatment modalities and outcome. Mean follow-up was 9 years. Results: Using the 8th edition, 97.5% patients filled in stage I-II category versus 76.4% before, of whom 28.2% were at intermediate/high risk compared to 16.7% before (p=0.001). Disease specific mortality (DSM) in stage I-II was 0% (0/11) for edition 7 and 1.5% (6/11) for edition 8 (p=0.069). Persistency rates at 1 year and last visit were 25.5% vs 16.6% (p=0.013) and 15% vs 10% (p=0.08) for stage I-II and 56.5% vs 33.3% (p=0.07) and 42.8% vs 18.7% (p=0.045) for stage II only. Of 124 patients in the 45-54 age-range, 37 shifted from stage III-IV to stage I-II, 62% were intermediate/high risk, 42% had persistency at 1 year and 22% at last visit, and DSM was 5.4%. In this group, distant metastases at diagnosis and all-time were 14.3% and 22.2%, respectively. Conclusion: The new TNM classification appears to underestimate disease severity, outcome and mortality in a considerable group of patients. Larger studies are needed to validate our results   References:

  1. Davies L, Welch HG 2006 Increasing incidence of thyroid cancer in the United States, 1973-2002. JAMA 295, 2164 – 2167 10
  2. Lim H, Devesa SS, Sosa JA, Check D, Kitahara CM 2017 Trends in Thyroid Cancer Incidence and Mortality in the United States, 1974-2013. JAMA 317, 1338-1348
  3. Haugen BR, Alexander EK, Bible KC, Doherty GM, Mandel SJ, Nikiforov YE, et al. 2016 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer. Thyroid; 26:1–133.
  4. Tuttle M, Morris LF, Haugen B, et al. in AJCC Cancer Staging Manual 8th ed. pp. 1-19. By Amin MB, Edge SB, Greene FL (Eds) 2017 Springer, New York.
  5. Nixon IJ, Wang LY, Migliacci JC, Eskander A, Campbell MJ, Aniss A, Morris L, Vaisman F, Corbo R, Momesso D, Vaisman M, Carvalho A, Learoyd D, Leslie WD, Nason RW, Kuk D, Wreesmann V, Morris L, Palmer FL, Ganly I, Patel SG, Singh B, Tuttle RM, Shaha AR, Gönen M, Pathak KA, Shen WT, Sywak M, Kowalski L, Freeman J, Perrier N, Shah JP 2016 An international multiinstitutional validation of age 55 years as a cutoff for risk stratification in the AJCC/UICC staging system for well-differentiated thyroid cancer. Thyroid 26, 373 -380
  6. Adam MA, Thomas S, Hyslop T, Scheri RP, Roman SA, Sosa JA 2016 Exploring the relationship between patient age and cancer specific survival in papillary thyroid cancer: rethinking current staging systems. J. Clin. Oncol. 34, 4415-4420
  7. Tanase K, Thies ED, Mäder U, Reiners C, Verburg FA 2016 The TNM system (version 7) is the most accurate staging system for the prediction of loss of life expectancy in differentiated thyroid cancer. Clin. Endocrinol. 84, 284–291