ABSTRACT
At present,intensity modulated radiation therapy has been the main treatment of nasopharyngeal carcinoma.In the course of 6-7 weeks,most physicians use the initial formulation of the radiotherapy plan.Studies have indicated that the reduction of primary tumor and lymph nodes,as well as the reduction of normal tissue and body surface profile due to the weight loss,will affect the dose distribution of the target and the organs at risk,so as to influence the therapeutic effect of some patients.Therefore,it is necessary to reset and modify the target volumes during the radiotherapy for nasopharyngeal carcinoma.
ABSTRACT
In recent years,there has been a considerable research effort concerning the application of magnetic resonance imaging (MRI) for the external radiotherapy.This paper reviewed the progress of MRI in radiotherapy for cancer,such as magnetic resonance simulator,target volumes,dose calculation and efficacy evaluation.Furthermore,the potential applications of 4D-MRI and MRI guided radiotherapy are summarized.
ABSTRACT
Objective:To analyze the characteristics of regional lymph node metastasis in patients with resectable non-small cell lung cancer (NSCLC) and assess its clinical significance in surgical mediastinal lymph dissection and the target volume definition of postoperative radiotherapy. Methods:We retrospectively reviewed 810 patients with NSCLC, and analyzed the metastatic frequency of each regional lymph node station as well as the correlation between tumor location and regional lymph node metastases. Results:Re-gional lymph node metastases were significantly associated with the age of patients, histology, tumor size, and tumor location (P=0.013, 0.000, 0.009 and 0.000, respectively). Conclusion:The younger patients with left lung adenocarcinomas and large tumor size tended to regional lymph node metastases. The trend of regional lymphatic drainage in the lobes of lung occurred differently. The prior location of involved regional lymph nodes in different lobes of the NSCLC patients was as follows:The station 2-4 for right upper lobe tumors, the station 2-4 and 7 for right middle lobe tumors and right lower lobe tumors, the station 5-6 for left upper lobe tumors, and the station 5-6 and 7 for left lower lobe tumors. We should pay more attention to the regions regarding the higher frequencies of lymph node metastases, when determining the extent of lymph node dissection or delineating the target volume of postoperative radiotherapy for NSCLC patients.
ABSTRACT
Objective To explore the reasonable clinical target volumes by analyzing the characteristic of mediastinal lymph node metastases in non-small-cell lung cacer (NSCLC).Methods 291 NSCLC patients was performed pre-therapy CT scans,and the incidence of mediastinal lymph node metastases was analysed.Results Among the 152 patients with right lung NSCLC,the incidence of involvement of the ipsilateral supraclavicular lymph nodes was 15.8 ％ (24/152),and the incidence of involvement of the contralateral lymph nodes was 6.6 ％ (10/152).The highest incidence of mediastinal nodal involvement occurred in the ipsilateral hilar nodes (59.2 ％),followed by area 4R (56.6 ％),area 1-2R (36.2 ％),area 7 (33.6 ％),area 4L(20.4 ％),area 10-11L (5.9 ％),area 6 (3.9 ％),area 5 (2.0 ％),area 1-2L (2.0 ％),respectively.Among the 139 patients left lung NSCLC,the incidence of involvement of the ipsilateral supraclavicular lymph nodes was 15.8 ％ (23/139),and the incidence of involvement of the contralateral lymph nodes was 5.8 ％ (8/139).The highest incidence of mediastinal nodal involvement occurred also in the ipsilateral hilar nodes (54.0 ％),followed by area 7 (33.8 ％),area 4R (26.6 ％),area 4L (24.5 ％),area 1-2R (15.8 ％),area 5 (10.8 ％),area 6 (9.4 ％),area 1-2L (5.8 ％),area 10-11R (5.0 ％) respectively.Conclusion The right side primaries or left side primaries of NSCLC have different high risk lymph node areas for metastasis,and selective irradiation to these lymph node areas maybe increase the tumor control rate and reduce the recurrence rate.
ABSTRACT
ObjectiveTo analyze intrathoracic or extrathoracic recurrence pattern after surgical resection of thoracic esophageal squamous cell carcinoma (TESCC) and its help for further modify and improvement on the target of postoperative radiation therapy. Methods One hundred and ninety-five patients who had undergone resection of TESCC at the Cancer Hospital,Chinese Academy of Medical Sciences enrolled from April 1999 to July 2007.Sites of failure on different primary location of esophageal cancer were documented.Results Patients with upper or middle thoracic esophageal cancer had higher proportion of intrathoracic recurrence.Patients with lower thoracic esophageal cancer had more intrathoracic reccurence and abdominal lymph node metastatic recurrence.Histological lymph node status has nothing to do with intrathoracic recurrence,supraclavicular lymph node ( SLN ) metastasis or distant metastasis ( χ2 =1.58,0.06,0.04,P =0.134,0.467,0.489,respectively),whereas the chance of abdominal lymph node metastases in N positive patients was significantly higher than that in N0 patients (28.7％: 10.6％,χ2 =9.94,P =0.001 ),and so did in middle thoracic esophageal cancer ( 20.0％: 5.6％,χ2 =5.67,P =0.015). Anatomic recurrence rate of patients with proximal resection margin no more than 3 cm was significantly higher compared to those more than 3 cm (25.0％: 11.3％,χ2=5.65,P=0.019).ConclusionsMediastinum is the most common recurrence site.According to recurrence site,the following radiation targets are recommended:when tumor was located at the upper or middle thoracic esophagus with negative N status,the mediastinum,the tumor bed and the supraclavicular region should be included as postoperative RT target;when tumor was located at the middle thoracic esophagus with positive N or located at the lower thoracic esophagus,the abdominal lymph node should be added.If the proximal resection margin was no more than 3 cm,the anastomotic-stoma should be included.
ABSTRACT
Objective To evaluate the impact of breathing motion on target volume and the factors influencing the set-up errors during tangential whole breast irradiation.Methods From Jan 2003 to Dec 2003,patients with early-stage breast cancer after breast conserving surgery,were selected to be eligible for the study.All patients were immobilized in treatment position by breast beard of Med-Tec 250.The motion of the breast treatment volume was observed on a fluoroscope in different directions under free breathing in 16 patients.The set-up errors in different dimensions during irradiation were measured by weekly portal films (PF) in comparison with digital reconstructed radiographs (DRR) in 11 patients.Results The central lung distance (CLD) variation during free breathing was (2.1?1.2) mm which is greater than the motion to- wards the other directions.By comparing the PF and DRR,the systemic error,random error and overall er- ror in the outer,inner and cranio-caudal directions was 1.9,1.6,2.5 and 2.4,1.7,3.1 and 2.6,2.3, 3.5 mm,respectively.In addition,the discrepancy of the treatment position in cranio-caudal direction and breast volume was most obvious at the beginning 2 weeks with the peak of breast volume at the second week. It decreased gradually during the following 3 weeks.Conclusions This study suggests that the mean value of the motion of the breast target volume during one breathing cycle is less than 2 mm.The set-up errors dur- ing irradiation is the greatest in cranio-caudal direction,suggesting that the fixing precision of the breast board should be further improved.The set-up error during irradiation are most obvious at the beginning two weeks,with the peak of the breast volume in the second week.