Objective To propose a new N staging system for nasopharyngeal carcinoma based on intensity-modulated radiotherapy (IMRT) and Radiation Therapy Oncology Group (RTOG) guidelines for cervical lymph node levels.Methods A retrospective analysis was performed in 324 patients with newly diagnosed nasopharyngeal carcinoma who had no distant metastasis confirmed by pathology and received IMRT in the Department of Radiation Oncology in The First Affiliated Hospital of Guangxi Medical University from January 2010 to December 2011.They were restaged according to the 7thedition of UICC/AJCC staging system for nasopharyngeal carcinoma.The survival rates were estimated using the Kaplan-Meier method and the log-rank test was used for univariate prognostic analysis.The Cox proportional hazards model was used for multivariate prognostic analysis.Results Of 324 patients,269(83.0%) had lymph node metastasis.The median follow-up was 58 months (6-77 months).The 5-year overall survival,disease-free survival,relapse-free survival,and distant metastasis-free survival rates were 84.8%,77.1%,92.7%,and 80.5%,respectively.Univariate and multivariate analyses of patients with positive cervical lymph nodes revealed that retropharyngeal lymph node status,cervical lymph node level,and laterality were evaluated as independent prognostic factors for nasopharyngeal carcinoma.According to the hazard ratio calculated,the N staging system was revised as follows:N0:no regional lymph node metastasis;N1:VⅡ a or/and unilateral levels (I,Ⅱ,Ⅲ,Va) involvement;N2:bilateral levels (I,Ⅱ,Ⅲ,Va) involvement;N3:levels IVa,Vb,and IVb+Vc involvement.Conclusions The proposed N staging system is based on IMRT and RTOG guidelines for lymph node levels and more practical,and can provide highly objective prediction of outcome and guide treatment in nasopharyngeal carcinoma.

Objective To explore the relationship between positive cervical lymph nodes and distant metastasis after intensity-modulated radiotherapy(IMRT)in patients with nasopharyngeal carcinoma(NPC). Methods A retrospective analysis was performed on the clinical data of 474 patients who were newly diagnosed with NPC but no distant metastasis and received IMRT from 2010 to 2012. The survival rates were calculated by the Kaplan-Meier method. The log-rank test was used for comparison of survival rates and univariate prognostic analysis. The multivariate analysis was made by the Cox regression model. Results In the 474 patients, 400 had positive cervical lymph nodes and 122 had residual masses in the neck after IMRT. The four-year distant metastasis, overall survival, disease-free survival, local relapse-free survival, and distant metastasis-free survival(DMFS)rates were 13.71%(65/474), 82.9%, 81.4%, 93.5%, and 86.3%, respectively. The univariate and multivariate analyses showed that treatment approach, lymph node metastases in lower neck Ⅳ/Ⅴb/Ⅴcregions, the greatest diameter of the positive cervical lymph nodes, the diameter of residual lymph nodes, and time to lymph node recession were independent prognostic factors for DMFS(all P<0.05). Conclusions Chemoradiotherapy can reduce the distant metastasis rate after IMRT for NPC. The larger the cervical lymph nodes are,the more likely there are residual masses;the larger the residual cervical lymph nodes are, the higher risk of distant metastasis there is. Large cervical lymph nodes(≥6 cm),residual masses larger than 1 cm,and residual masses at 3 months after IMRT are negative prognostic factors for DMFS after IMRT for NPC. Better intervention treatment approaches need to be explored.

Objective:To explore the safety and effectiveness of medium-frequency electrotherapy for increasing the volume of the latissimus dorsi muscle.Methods:Fifteen adult New Zealand white rabbits were randomly divided into three groups, namely group A, group B, and group C, with 5 rabbits in each group. This was a self-control study, with the right latissimus dorsi muscle as the experimental group and the left latissimus dorsi muscle as the control group. The three groups corresponded to three different current intensity levels: 7.062 mA for group A (6th gear), 10.593 mA for group B (9th gear), and 14.124 mA for group C (12th gear). After the 12th, 24th, and 36th sessions of the experiment, ultrasonography was used to collect the thickness of the latissimus dorsi muscle. After the 36th electrostimulation, the latissimus dorsi muscle samples were collected to measure their in vivo muscle thickness and wet weight and were then sent for HE and MASSON staining.Results:After the 12th, 24th, and 36th electrostimulation sessions, ultrasonographic sampling in groups A and B showed an increase in the thickness of the right latissimus dorsi muscle compared to the left; for example, the thickness on the right of group B increased by 37.8%. The wet weight data collected after the 36th electrostimulation in groups A and B showed an increase in the right latissimus dorsi muscle compared to the left; for example, the wet weight on the right of group B increased by 5.04%.Conclusions:Different electrostimulation modes of medium-frequency therapy technology can induce muscle fiber thickening or atrophy. In this experiment, the 9th gear (10.593 mA) of medium-frequency therapy technology may be a suitable choice for inducing muscle fiber thickening, and the 12th gear (14.124 mA) may be a suitable choice for inducing skeletal muscle thinning.