Li Lin1, Yao Lu2, Xiao-Ju Wang3, Hui Chen4, Sha Yu4, Jiao Tian4, Guan-Qun Zhou1, Lu-Lu Zhang1, Zhen-Yu Qi1, Jiang Hu1, Jun Ma1, Ying Sun5. 1. Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, People's Republic of China. 2. School of Data and Computer Science, Sun Yat-sen University, Guangzhou, People's Republic of China; Guangdong Province Key Laboratory of Computational Science, Guangzhou, People's Republic of China. 3. Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, People's Republic of China; Department of Radiation Oncology, Hangzhou Cancer Center, Hangzhou, People's Republic of China. 4. School of Data and Computer Science, Sun Yat-sen University, Guangzhou, People's Republic of China. 5. Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, People's Republic of China. Electronic address: sunying@sysucc.org.cn.
Abstract
PURPOSE: To establish the regional lymph node (LN) distribution probability map and draw the neck clinical target volume specific to nasopharyngeal carcinoma (NPC). METHODS AND MATERIALS: One thousand patients with pathologically proven NPC were enrolled from January 2010 to December 2011. The center point of the LNs with a minimal axial diameter of ≥4 mm was marked on a single treatment planning computed tomography scan. The neck LN levels I to X using the 2013 updated international consensus guidelines were also contoured. LN distribution probability maps and distribution curves were established. The relationships between the LN distribution and consensus guidelines were analyzed to propose modifications for clinical target volume boundaries specific to NPC. RESULTS: A total of 10,651 LNs from 959 patients were marked. Based on the distribution of LNs and consensus guidelines, most of the LN levels defined in the 2013 updated consensus guidelines were confirmed to be comprehensive and applicable for NPC. However, for level Vb, 13.3% of cases (11 of 83) had LNs beyond the posteromedial border. For level VIIa (retropharyngeal LN), 1.5% of cases (12 of 819) had LNs above the cranial boundary, and 5 cases had LNs that emerged in the medial group. Moreover, we confirmed that no LN had been detected in certain areas of levels Ib, II, IVa, and Vc. Accordingly, a new level VIIc was proposed to include the medial group of retropharyngeal LNs, moderately extended boundaries for levels Vb and VIIa were recommended, and reduced boundaries are possibly adaptable for levels Ib, II, IV, and Vc. CONCLUSIONS: Most LN levels in the 2013 updated consensus guidelines are comprehensive and applicable for NPC. We have proposed a new level VIIc to include a medial group of retropharyngeal LNs, recommended moderate extended boundaries for levels Vb and VIIa, and suggested that the boundaries for levels Ib, II, IV, and Vc might be reduced.
PURPOSE: To establish the regional lymph node (LN) distribution probability map and draw the neck clinical target volume specific to nasopharyngeal carcinoma (NPC). METHODS AND MATERIALS: One thousand patients with pathologically proven NPC were enrolled from January 2010 to December 2011. The center point of the LNs with a minimal axial diameter of ≥4 mm was marked on a single treatment planning computed tomography scan. The neck LN levels I to X using the 2013 updated international consensus guidelines were also contoured. LN distribution probability maps and distribution curves were established. The relationships between the LN distribution and consensus guidelines were analyzed to propose modifications for clinical target volume boundaries specific to NPC. RESULTS: A total of 10,651 LNs from 959 patients were marked. Based on the distribution of LNs and consensus guidelines, most of the LN levels defined in the 2013 updated consensus guidelines were confirmed to be comprehensive and applicable for NPC. However, for level Vb, 13.3% of cases (11 of 83) had LNs beyond the posteromedial border. For level VIIa (retropharyngeal LN), 1.5% of cases (12 of 819) had LNs above the cranial boundary, and 5 cases had LNs that emerged in the medial group. Moreover, we confirmed that no LN had been detected in certain areas of levels Ib, II, IVa, and Vc. Accordingly, a new level VIIc was proposed to include the medial group of retropharyngeal LNs, moderately extended boundaries for levels Vb and VIIa were recommended, and reduced boundaries are possibly adaptable for levels Ib, II, IV, and Vc. CONCLUSIONS: Most LN levels in the 2013 updated consensus guidelines are comprehensive and applicable for NPC. We have proposed a new level VIIc to include a medial group of retropharyngeal LNs, recommended moderate extended boundaries for levels Vb and VIIa, and suggested that the boundaries for levels Ib, II, IV, and Vc might be reduced.