| BackgroundThe rate of Nasopharyngeal carcinoma with lymph node metastasis is morethan70%. It is consensus that give66~70Gy irradiation dose to positivelymph nodes. however，there is no central necrosis about retropharyngeal lymphnodes which less than5mm and neck I~VI area which less than10mm, ringenhancement or small lymph IMRT dose of target design and extracapsularinvasion remains controversial.ObjectiveTo observe the dynamic changes of nasopharyngeal small lymph nodesafter the radiation therapy and long-term efficacy analysis.Materials and MethodsRetrospective analysis2005.1-2011.1pathologically confirmed359casesof CT and MRI showed the presence of small lymph nodes without distantmetastasis-na ve patients with nasopharyngeal carcinoma, were irradiated usingIMRT techniques, metastatic cervical lymph nodes (GTV-ln) median dose D9570.8Gy (65.4~77.5Gy)/27~37F, upper cervical lymphatic drainage area(CTVln) median dose D9551.3Gy (45.4~60.9Gy)/22~32F, under the neck using CO60tangential field irradiation dose44~52Gy/22~26f. The largestcollection of patients with tumor stage, chemotherapy, targeted therapyGenerally, patients recorded a small piece of the total number of lymph nodes,RTOG zoning cases, patients were measured before, when a small lymph nodeirradiation50Gy, six months after the end of radiotherapy when each one smalllymph nodes diameter and axial diameter, calculate the percentage change inlymph node diameter line (retreat rate), Logistic regression analysis betweensmall lymph nodes shrink rate and dose of chemotherapy. While long-termfollow-up, regional control rate statistics into the group of patients and survival.Survival analysis using the Kaplan-Meier method, multivariate analysis usingCOX proportional hazards regression model.Results359cases of patients with small lymph nodes shrink when≥30%at50Gyand65patients (18%), narrowing≥50%,34patients (9%); six months afterthe end of treatment follow-up, narrowing≥30%had127cases (35%),narrowing≥50%and69patients (19%). Univariate and multivariate analysisshowed, N stage, the dose of small lymph nodes and total number of smalllymph nodes are independent prognostic factors for small lymph retreat rate,P <0.05.The N staging is higher or the the dose of small lymph nodes is higheror the more of the total number of small lymph nodes, the withdrawal rate ishigher. According to follow-up results of the qualitative evaluation of the lymphnodes. Use the diameter of the lymph nodes before treatment draw the ROCcurve, parapharyngeal lymph node diameter5mm, neck lymph node9mm I~VImay refer to as a criterion of positive lymph nodes.All patients were followed up for more than3years,2cases of cervicallymph node recurrence,5-year regional control rate (RC, Regional Control) 99.4%. the dose of small lymph and whether chemotherapy did not affect thefive-year RC. Univariate and multivariate analysis showed that the dose ofsmall lymph nodes is not a factor for survival. However, whetherchemotherapy is the independent factor of DMFS (Distance Metastasis FreeSurvival), DSS (Disease-specific Survival) and OS (Overall survival)(P <0.05)without affecting the LC (Local Control).3-year and5-year LC, DMFS, DSS,OS were97.1%and96.7%,86.4%and81.6%,94.3%and86.2%,95.8%and85.1%respectively.Conclusions1) The retreat rate of small lymph nodes after radiotherapy is positivecorrelation to tumor N stage, clinical stage, the dose of small lymph nodes andthe number of lymph nodes.2)The small lymph nodes was also good localcontrolled in the50Gy dose and could be designed as CTVln not GTVln.3)Parapharyngeal diameter5mm, I~VI area of the neck9mm likely to bediagnosed as positive lymph nodes, one reference. Radiotherapy in clinicalpractice can combine PET-CT, SPIO and other test results into account. |
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