Résumé
Objective:According to 2013 updated consensus guidelines of neck node levels, the distribution characteristics of cervical lymph nodes of nasopharyngeal carcinoma (NPC) were analyzed, aiming to provide preliminary reference for the clinical target volume (CTV) delineation of level Ⅴ in NPC.Methods:A total of 1110 patients pathologically diagnosed with NPC from 2012 to 2020 were retrospectively recruited for further analysis. All patients’ MRI and contrast-enhanced CT simulation scan imageswere retrospectively reviewed, metastatic lymph nodes were mapped using the 2013 International Consensus Guidelines. Then, the correlation between Ⅴa, Ⅴb and Ⅴc metastatic lymph nodes and other lymph nodes was analyzed. An NPC case diagnosed with T 1N 0M 0 was selected as the baseline standard for the normal anatomical structure and proportion of Ⅴc area. The metastatic lymph nodes in Vc were delineated on the CT simulation scan image of sample case, and the distribution characteristics of the metastatic lymph nodes inⅤc were analyzed. Results:Among the 1110 patients, 1004(90.5%) patients had lymph node metastases. The most common area of metastatic lymph node levels were level Ⅶa (74.7%) and level Ⅱb(70.7%), and the skip metastasis of lymph nodes was rare (1.0%). The multivariate analysis showed lymph node metastasis in level Va was correlated with levels Ⅱb, Ⅲ, Ⅳa, Ⅴb, and Ⅷ region ( P=0.010, 0.001, 0.001, 0.001, 0.037). Lymph node metastasis in level Ⅴb was correlated with levels Ⅲ, Ⅳa, Ⅴa and Ⅴc region ( P=0.006, 0.001, 0.001, 0.001). Lymph node metastasis in level Ⅴc was correlated with levels Ⅳb and Ⅴb region ( P=0.008, 0.001). There were 28 cases of lymph node metastasis in levelⅤc. A total of 38 metastatic lymph nodes were counted in level Vc. Among them, 33(86.8%) lymph nodes were located in the medial of the omohyoid muscle (Ⅴc-1 region), and 5(13.2%) were located in the lateral of the omohyoid muscle (Ⅴc-2 region). Conclusions:This study reflects the principle of individualized CTV delineation, which is based on the levels of nodal spread in NPC patients. When correlation is observed among different level V, V should be delineated as the moderate risk lymphatic drainage (CTV n2). It is recommended to individualized delineate level Vc when the CTV n2 covers Vc. The Ⅴc-2 region should be delineated as CTV n2 only when there is nodal spread in the ipsilateral Ⅴc-1 region.
Résumé
Objective To define the patterns of local extension and nodal involvement in patients with early stage nasal NK/T-cell lymphoma, and to improve the delineation of clinical target volume.Methods Two hundred and twenty-two patients consecutively diagnosed with nasal NK/T-cell lymphoma were reviewed.All patients had stage Ⅰ E/Ⅱ E diseases.CT/MRI images were reviewed to determine the local invasion of adjacent organs or structures and involvement of lymph node.Results 143 of 222(64%) patients had primary tumor extended into adjacent organs or structures from nasal cavity.According to the incidence rates of tumor extension, the involved organs or structures were subclassified into three subgroups:high risk (≥40%):ethmoid sinus (60%) and maxillary sinus (55%);intermediate risk (5%-40%):nasopharynx (39%), skin (22%), oropharynx (12%), orbit (10%), and hard palate (10%);and low risk (≤5%):sphenoid sinus (3%), soft plate (3%),frontal sinus (3%) and skull base (1%).Cervical lymph node metastasis occurred in 16%(36/222) of the patients and these patients were staged as Ⅱ E.Thirty-three patients with stage Ⅱ E disease had available images and were analyzed for the pattern of nodal involvement.Submandibular or submental (57%) and the upper cervical lymph nodes (57%) were the most commonly involved sites of nodal region.For the 24 patients with primary tumor located in the unilateral nasal cavity, 54% presented with contralateral cervical lymph node metastasis.Whereas for the 9 patients with primary tumor located in the bilateral nasal cavity, 57% had bilateral cervical lymph node metastasis.For the 88 patients with extensive stage Ⅰ E disease who did not receive irradiation to the cervical lymph node, only one patient (1%) had disease relapse in cervical lymph node.Furthermore, all patients with disease extended to nasopharynx (n= 23) or oropharynx (n= 8) did not receive prophylactic cervical lymph node irradiation, and none of them developed cervical lymph node relapse.Conclusions The delineation of clinical target volume for early stage nasal NK/T-cell lymphoma should be determined by the risk of involvement of paranasal structures and cervical lymph node.Prophylactic neck irradiation is not recommended for patients with stage Ⅰ disease.