Mijin Kim1, Hye In Kim2, Min Ji Jeon3, Hee Kyung Kim4, Eun Heui Kim5, Hyon-Seung Yi6, Eun Sook Kim7, Hosu Kim8, Bo Hyun Kim5, Tae Yong Kim3, Sun Wook Kim9, Ho-Cheol Kang4, Won Bae Kim3, Jae Hoon Chung9, Young Kee Shong3, Tae Hyuk Kim10, Won Gu Kim11. 1. Division of Endocrinology and Metabolism, Department of Internal Medicine, Biomedical Research Institute, Pusan National University Hospital, Busan, Republic of Korea; Division of Endocrinology and Metabolism, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea. 2. Division of Endocrinology and Metabolism, Department of Medicine, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Republic of Korea. 3. Division of Endocrinology and Metabolism, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea. 4. Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Republic of Korea. 5. Division of Endocrinology and Metabolism, Department of Internal Medicine, Biomedical Research Institute, Pusan National University Hospital, Busan, Republic of Korea. 6. Department of Internal Medicine, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon, Republic of Korea. 7. Department of Internal Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Republic of Korea. 8. Division of Endocrinology, Department of Medicine, Gyeongsang National University Changwon Hospital, Gyeongsang National University School of Medicine, Changwon, Republic of Korea. 9. Division of Endocrinology and Metabolism, Department of Medicine, Thyroid Cancer, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. 10. Division of Endocrinology and Metabolism, Department of Medicine, Thyroid Cancer, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. Electronic address: taehyukmd.kim@samsung.com. 11. Division of Endocrinology and Metabolism, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea. Electronic address: wongukim@amc.seoul.kr.
Abstract
OBJECTIVES: This study aimed to evaluate the proposed changes in the eighth edition of the tumor-node-metastasis staging system (TNM-8) compared with the seventh edition (TNM-7) in terms of pathologic subtypes, using a large multicenter thyroid cancer cohort. MATERIALS AND METHODS: We retrospectively reviewed 7717 patients with papillary (PTC) and 273 with follicular thyroid carcinoma (FTC) who underwent thyroid surgery between 1996 and 2005. We assessed the proportion of variation explained (PVE) to compare the predictive accuracy of disease-specific survival (DSS). RESULTS: During a median 11.3 years of follow-up, 169 (2%) disease-specific deaths were recorded. In patients with PTC, the 10-year DSS rates of stages I, II, III, and IV disease in TNM-8 were 99.6%, 95.7%, 81.5%, and 54.8%, respectively; the corresponding rates in TNM-7 were 99.6%, 98.4%, 98.4%, and 90.1%, respectively. In patients with FTC, the 10-year DSS rates of stages I, II, III, and IV disease in TNM-8 were 97.2%, 69.8%, 50.0%, and 45.5%, respectively; the corresponding rates in TNM-7 were 98.3%, 90.0%, 92.3%, and 42.1%, respectively. Comparing TNM-7 and TNM-8, the PVE values increased from 3.4% to 4.7% in the PTC group, whereas they decreased from 17.5% to 14.5% in the FTC group. CONCLUSION: Our study suggests that the changes in TNM-8 have improved the clinical usefulness of the TNM staging system in terms of predicting DSS in patients with PTC but not FTC. Further studies to establish a more predictable TNM staging system that focuses on patients with FTC are necessary.
OBJECTIVES: This study aimed to evaluate the proposed changes in the eighth edition of the tumor-node-metastasis staging system (TNM-8) compared with the seventh edition (TNM-7) in terms of pathologic subtypes, using a large multicenter thyroid cancer cohort. MATERIALS AND METHODS: We retrospectively reviewed 7717 patients with papillary (PTC) and 273 with follicular thyroid carcinoma (FTC) who underwent thyroid surgery between 1996 and 2005. We assessed the proportion of variation explained (PVE) to compare the predictive accuracy of disease-specific survival (DSS). RESULTS: During a median 11.3 years of follow-up, 169 (2%) disease-specific deaths were recorded. In patients with PTC, the 10-year DSS rates of stages I, II, III, and IV disease in TNM-8 were 99.6%, 95.7%, 81.5%, and 54.8%, respectively; the corresponding rates in TNM-7 were 99.6%, 98.4%, 98.4%, and 90.1%, respectively. In patients with FTC, the 10-year DSS rates of stages I, II, III, and IV disease in TNM-8 were 97.2%, 69.8%, 50.0%, and 45.5%, respectively; the corresponding rates in TNM-7 were 98.3%, 90.0%, 92.3%, and 42.1%, respectively. Comparing TNM-7 and TNM-8, the PVE values increased from 3.4% to 4.7% in the PTC group, whereas they decreased from 17.5% to 14.5% in the FTC group. CONCLUSION: Our study suggests that the changes in TNM-8 have improved the clinical usefulness of the TNM staging system in terms of predicting DSS in patients with PTC but not FTC. Further studies to establish a more predictable TNM staging system that focuses on patients with FTC are necessary.