Hye In Kim1, Kyunga Kim2, So Young Park1, Jun-Ho Choe3, Jung-Han Kim3, Jee Soo Kim3, Young Lyun Oh4, Soo Yeon Hahn5, Jung Hee Shin5, Hyeon Seon Ahn2, Sun Wook Kim1, Tae Hyuk Kim6, Jae Hoon Chung7. 1. Division of Endocrinology & Metabolism, Department of Medicine, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. 2. Statistics and Data Center, Research Institute for Future Medicine, Samsung Medical Center, Seoul, Republic of Korea. 3. Division of Breast and Endocrine Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. 4. Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. 5. Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. 6. Division of Endocrinology & Metabolism, Department of Medicine, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. Electronic address: taehyukmd.kim@samsung.com. 7. Division of Endocrinology & Metabolism, Department of Medicine, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. Electronic address: thyroid@skku.edu.
Abstract
BACKGROUND: In the eighth edition, TNM staging system omits location of nodal metastasis as a criterion for staging patients with papillary thyroid cancer (PTC). Accordingly, all of non-metastatic N1b PTC patients are classified as stage I or II solely according to an age-cutoff of 55 years. We hypothesized that incorporating other lymph node (LN) factors into TNM staging system would better predict cancer-specific mortality (CSM) in N1b patients. METHODS: We enrolled 745 N1b PTC patients without distant metastasis. Alternative prognostic LN factors and cut-off points were assessed using Cox regression and time-dependent ROC analysis. Alternative prognostic groupings were derived based on minimal hazard differences for CSM among groups stratified by LN risk and age. We assessed accuracy of CSM prediction. RESULTS: Lateral LN ratio (LNR) >0.3 and largest LN size >3 cm were prognostic factors for CSM. Stage II patients (eighth edition) with LN risk (lateral LNR >0.3 or largest LN size >3 cm) had a much higher CSM rate (20.9%) than those in the same stage without LN risk (3.2%). Alternative prognostic grouping (Group 1, <55 years without LN risk; Group 2, <55 years with LN risk or ≥55 years without LN risk; and Group 3, ≥55 with LN risk) achieved higher proportions of variance explained (PVEs) for predicting CSM (10.7%) than those of the eighth edition TNM staging system (4.8%). CONCLUSIONS: The proposed grouping for N1b patients using LN risk can distinguish patients with poor prognosis from those with good prognosis better than the eighth edition TNM staging system.
BACKGROUND: In the eighth edition, TNM staging system omits location of nodal metastasis as a criterion for staging patients with papillary thyroid cancer (PTC). Accordingly, all of non-metastatic N1b PTC patients are classified as stage I or II solely according to an age-cutoff of 55 years. We hypothesized that incorporating other lymph node (LN) factors into TNM staging system would better predict cancer-specific mortality (CSM) in N1b patients. METHODS: We enrolled 745 N1b PTC patients without distant metastasis. Alternative prognostic LN factors and cut-off points were assessed using Cox regression and time-dependent ROC analysis. Alternative prognostic groupings were derived based on minimal hazard differences for CSM among groups stratified by LN risk and age. We assessed accuracy of CSM prediction. RESULTS: Lateral LN ratio (LNR) >0.3 and largest LN size >3 cm were prognostic factors for CSM. Stage II patients (eighth edition) with LN risk (lateral LNR >0.3 or largest LN size >3 cm) had a much higher CSM rate (20.9%) than those in the same stage without LN risk (3.2%). Alternative prognostic grouping (Group 1, <55 years without LN risk; Group 2, <55 years with LN risk or ≥55 years without LN risk; and Group 3, ≥55 with LN risk) achieved higher proportions of variance explained (PVEs) for predicting CSM (10.7%) than those of the eighth edition TNM staging system (4.8%). CONCLUSIONS: The proposed grouping for N1b patients using LN risk can distinguish patients with poor prognosis from those with good prognosis better than the eighth edition TNM staging system.
Authors: Guoshu Bi; Tao Lu; Guangyu Yao; Yunyi Bian; Mengnan Zhao; Yiwei Huang; Yi Zhang; Liang Xue; Cheng Zhan; Hong Fan Journal: Cancer Manag Res Date: 2019-11-06 Impact factor: 3.989