Patterns of local extension and nodal involvement in early stage nasal NK/T-cell lymphoma and delineation of clinical target volume / 中华放射肿瘤学杂志

ABSTRACT

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 subgroupshigh 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.