Clinical Dosimetry Study Of Radiation-Induced Temporal Lobe Damage In Patients With Local Advanced NPC Treated By Adaptive IMRT

Background:Nasopharyngeal cancer is a more common head and neck cancer, especially in southern China and Southeast Asian countries have a higher prevalence, radiotherapy is the main treatment. Local control rate of nasopharyngeal cancer was positively correlated with the target volume dose. In recent years, due to the gradual development of IMRT and other radiotherapy, the efficacy of continuous improvement, the survival time is getting longer and longer, higher and higher demands on the quality of life. Radiation brain injury is an important complication of the quality of life of patients with nasopharyngeal carcinoma.Recent studies have pointed out that the radiotherapy of head and neck cancer will be obvious anatomical location changes, multi-course radiotherapy plan may lead to the target and normal tissue and organ doses to change. Re-plan design during treatment of patients with CT MRI image will be an effective means to solve the target and normal tissues and organs caused by changes in dose change, so as to improve the target dose, reducing the dose of normal tissues and organs, and improve patient the long-term survival quality. But there are no results on the bulk case studies of multi-course radiotherapy affect the temporal lobe dose. This study retrospectively compared a group of skull base involvement of primary NPC patients in the IMRT change and do not change the program’s long-term efficacy and radiation brain injury incidence, and some patients with temporal lobe dosimetry analysis to evaluate the impact of multi-process intensity modulated radiation therapy of temporal lobe damage.Objective:Recalling the collection and analysis of intensity modulated radiation therapy of nasopharyngeal carcinoma patient data, research and compare the one-way and multi-trip intensity-modulated radiotherapy radioactive temporal lobe damage and patients with long-term quality of life.Materials and methods:IMRT radiation therapy acceptance in Sichuan Cancer Hospital from January2002to January2010and no distant metastasis in patients with primary NPC screening to meet the conditions of patients with a total of 221cases. Divided into two groups:one way of IMRT+chemotherapy in161cases; multi-ride of IMRT+chemotherapy,60cases; All the patients, telephone and correspondence follow-up, and get patients regularly reviewed data, including MRI/CT examination, chest radiograph, and ECT, etc., to assess and The calculation of the nasopharynx, base of skull with intracranial control rate of radioactive temporal lobe necrosis, and patients with disease-free survival and overall survival.Results:All patients with median follow-up time was54.7months (6-96months), five years between the two groups of patients with nasopharynx, base of skull with intracranial control rate, overall survival there was no significant difference (P>0.05), using multi-trip intensity-modulated radiotherapy plan radical skull base involvement of T3, T4nasopharyngeal carcinoma, the temporal lobe to get better protection, radioactive temporal lobe damage is low. One-way intensity-modulated radiotherapy radioactive temporal lobe damage was14.7%; multi-trip intensity-modulated radiotherapy radioactive temporal lobe damage rate of5%. The average occurrence of radioactive temporal lobe damage in patients with left and right temporal lobe of D5were76.67±5.61Gy and74.52±5.82Gy significantly higher than non-radioactive temporal lobe necrosis, the left and right temporal lobe of the D5average value were64.52±4.82Gy and64.71±4.74Gy (P<0.05). Conclusion:5-year follow-up results prompted multi-trip plan treatment of advanced nasopharyngeal carcinoma (D-MFS) with no difference between one-way plan for improving the long-term local control rate (LC) and distant metastasis-free rate. But can improve disease-free survival (DFS) and overall survival (OS).multi-trip program to treat patients with radioactive temporal lobe injury rate is lower than the one-way plan treatment of patients with temporal lobe injury incidence rate of5%in the case of the same total dose, multi-trip plans. One-way plan the temporal lobe damage was14.7%split doses greater than2Gy/F temporal lobe injury rate increased; older than the age of50patients with temporal lobe damage rate in less than50-year-old patients.