Prognostic value of retropharyngeal lymph nodes in nasopharyngeal carcinoma treated by intensity modulated radiotherapy (IMRT) / 中华放射医学与防护杂志

ABSTRACT

Objective To investigate the correlation of the the positive rate and necrosis rate of retropharyngeal lymph nodes with the clinical effects of intensity modulated radiotherapy (IMRT) in treatment of nasopharyngeal carcinoma (PNC).Methods Seventy-two patients with PNC,50 males and 22 females,with the median age of 50,underwent IMRT delivered into 33 times.The retropharyngeal lymph nodes involved and positive lymph nodes of neck were delineated on the CT image.The median dose and median fractionated dose for gross tumor volume (GTV) were 70.0 and 2.12 Gy respectively,and the median dose and median fractionated dose for clinical target volume (CTV) were 70.0 and 2.12 Gy respectively.The patients were followed up for 36 (5-54) months.Results The metastasis rate of the neck lymph nodes was 90.3％,the metastasis rates in the regions Ⅰ-Ⅴ were 2.8％,86.0％,51.4％,20.8％,and 37.5％,respectively.The metastasis rate of the retropharyngeal lymph nodes was 79.2％,and specifically the metastasis rates of the left,right,and bilateral retropharyngeal lymph nodes were 51.4％,45.9％,and 18.1％,respectively.The cross metastasis rate was 6.9％.Necrosis of the retropharyngeal lymph nodes was found in 15 cases.The necrosis rates of the left,right,and bilateral retropharyngeal lymph nodes were 21.6％,27.2％,15.4％,respectively.Retropharyngeal lymph nodes metastasis was significantly correlated with N stage and clinical stage(Fuzhou 92r =-0.383,-0.314,P ＜ 0.05 ; UICCr =-0.434,-0.306,P ＜ 0.05).Local recurrence was observed in 4 patients,6 patients had distant metastasis,and 7 patients died.The positiveness of retropharyngeal lymph nodes was significantly correlated with the recurrence rate,distant metastasis rate,survival rate,and disease free survival rate (r =0.085,0.138,-0.140,-0.124,P ＜ 0.05),and the necrosis of the retropharyngeal lymph nodes was significantly correlated with the recurrence rate and distant metastasis rate (r =0.256,-0.057,P ＜ 0.05),and not significantly correlated with the survival rate and disease free survival rate.Conclusions Retropharyngeal lymph nodes metastasis in NPC is correlated with the N stage and clinical stage.The positiveness of retropharyngeal lymph nodes is significantly correlated with local recurrence,distant metastasis,and survival.Necrosis of retropharyngeal lymph nodes in NPC is significantly correlated with local recurrence and distant metastasis after IMRT.