Wentao Fang1, Yun Wang2, Liewen Pang3, Zhitao Gu4, Yucheng Wei5, Yongyu Liu6, Peng Zhang7, Chun Chen8, Xinming Zhou9, Yangchun Liu10, Keneng Chen11, Jianyong Ding12, Yongtao Han13, Yin Li14, Zhentao Yu15, Yuan Liu4, Jianhua Fu16. 1. Department of Thoracic Surgery, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China. Electronic address: vwtfang12@shchest.org. 2. Department of Thoracic Surgery, West China Hospital, Sichuan University, Chengdu, China. 3. Department of Thoracic Surgery, Huashan Hospital, Fudan University, Shanghai, China. 4. Department of Thoracic Surgery, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China. 5. Department of Thoracic Surgery, Affiliated Hospital of Qingdao University, Qingdao, China. 6. Department of Thoracic Surgery, Liaoning Cancer Hospital, Shenyang, China. 7. Department of Endocrinology, Tianjin Medical University General Hospital, Tianjin, China. 8. Department of Thoracic Surgery, Fujian Medical University Union Hospital, Fuzhou, China. 9. Department of Thoracic Surgery, Zhejiang Cancer Hospital, Hangzhou, China. 10. Department of Thoracic Surgery, Jiangxi People's Hospital, Nanchang, China. 11. Department of Thoracic Surgery, Beijing Cancer Hospital, Beijing, China. 12. Department of Thoracic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China. 13. Department of Thoracic Surgery, Sichuan Cancer Hospital, Chengdu, China. 14. Department of Thoracic Surgery, Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, China. 15. Department of Esophageal Cancer, Tianjin Cancer Hospital, Tianjin, China. 16. Department of Thoracic Surgery, Guangdong Esophageal Cancer Institute, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangzhou, China. Electronic address: fujh@sysucc.org.cn.
Abstract
OBJECTIVES: To study the incidence and pattern of lymph node metastases in thymic malignancies. METHODS: This multicenter prospective observational trial with intentional lymph node dissection was carried out by the Chinese Alliance for Research in Thymomas (ChART). Data on patients with thymic tumors without pretreatment were collected prospectively. Results from this prospective study were then compared with those from a previously reported ChART retrospective study. RESULTS: Among 275 patients, metastasis was detected in 41 nodes (3.04%) in 15 patients (5.5%). The rate of lymph node metastasis was 2.1% (5/238) in patients with thymomas, 25% (6/24) in those with thymic carcinomas, and 50% (4/8) in those with neuroendocrine tumors (P < .001). The rate of lymph node metastasis in category T1 to T4 tumors was 2.7% (6/222) in T1, 7.7% (1/13) in T2, 18.4% (7/38) in T3, and 50% (1/2) in T4 (P < .001). Nodal involvement was significantly higher compared with the ChART retrospective study (5.5% vs 2.2%; P = .002), although the 2 groups were comparable in terms of tumor stage and histology. Metastasis was found in N1 nodes in 13 patients (86.7%) and in N2 nodes in 8 patients (53.3%); 6 patients (40%) had simultaneous N1/N2 diseases and 6 (40%) had multistation involvement. Based on World Health Organization histological classification and Union for International Cancer Control T category, patients were divided into a low-risk group (1/192; 0.5%) with T1-2 and type A-B2 diseases and a high-risk group (14/83; 16.9%) of category T3 and above or histology B3 and above tumors for nodal metastasis (P < .001). On multivariate analysis, type B3/thymic carcinoma/neuroendocrine tumors, category T3 or above, and N2 dissection predicted a greater likelihood of finding nodal metastasis. CONCLUSIONS: Lymph node involvement in thymic malignancies is more common than previously recognized, especially in tumors with aggressive histology and advanced T category. Intentional lymph node dissection increases the detection of nodal involvement and improves accuracy of staging. In selected high-risk patients, systemic dissection of both N1and N2 nodes should be considered for accurate tumor staging.
OBJECTIVES: To study the incidence and pattern of lymph node metastases in thymic malignancies. METHODS: This multicenter prospective observational trial with intentional lymph node dissection was carried out by the Chinese Alliance for Research in Thymomas (ChART). Data on patients with thymic tumors without pretreatment were collected prospectively. Results from this prospective study were then compared with those from a previously reported ChART retrospective study. RESULTS: Among 275 patients, metastasis was detected in 41 nodes (3.04%) in 15 patients (5.5%). The rate of lymph node metastasis was 2.1% (5/238) in patients with thymomas, 25% (6/24) in those with thymic carcinomas, and 50% (4/8) in those with neuroendocrine tumors (P < .001). The rate of lymph node metastasis in category T1 to T4 tumors was 2.7% (6/222) in T1, 7.7% (1/13) in T2, 18.4% (7/38) in T3, and 50% (1/2) in T4 (P < .001). Nodal involvement was significantly higher compared with the ChART retrospective study (5.5% vs 2.2%; P = .002), although the 2 groups were comparable in terms of tumor stage and histology. Metastasis was found in N1 nodes in 13 patients (86.7%) and in N2 nodes in 8 patients (53.3%); 6 patients (40%) had simultaneous N1/N2 diseases and 6 (40%) had multistation involvement. Based on World Health Organization histological classification and Union for International Cancer Control T category, patients were divided into a low-risk group (1/192; 0.5%) with T1-2 and type A-B2 diseases and a high-risk group (14/83; 16.9%) of category T3 and above or histology B3 and above tumors for nodal metastasis (P < .001). On multivariate analysis, type B3/thymic carcinoma/neuroendocrine tumors, category T3 or above, and N2 dissection predicted a greater likelihood of finding nodal metastasis. CONCLUSIONS: Lymph node involvement in thymic malignancies is more common than previously recognized, especially in tumors with aggressive histology and advanced T category. Intentional lymph node dissection increases the detection of nodal involvement and improves accuracy of staging. In selected high-risk patients, systemic dissection of both N1and N2 nodes should be considered for accurate tumor staging.