RESUMO
Objective:To analyze the mediastinal displacement of target volume in the postoperative radiotherapy (PORT) process for non-small cell lung cancer (NSCLC) and the value of mid-term evaluation.Methods:For 100 patients with postoperativeN 2 stage NSCLC, R 1-2 and any N staging, bone anatomy was utilized to measure the change of the first and second CT localization on the same level. Statistical analysis were performed using the WilCoxon, Kruskal-Wallis and χ2 tests. The cut-off values were calculated with the receiver operating characteristic (ROC) curve. Results:Among the included patients, in the PORT process, the mediastinal displacement in the x (front and rear), Y (left and right) and Z (upper and lower) directions were 0.04-0.53 cm, 0.00-0.84 cm and 0.00-1.27 cm, respectively, and the order of mediastinal displacement distance wasz > Y> X,respectively. According to the ROC curve calculation, the cut-off values were 0.263, 0.352 and 0.405, respectively, which were greater than the cut-off values in 25 cases (25%), 30 cases (30%) and 30 cases (30%), respectively. There was significant difference in the three-dimensionalmediastinal displacement ( P=0.007, <0.001 and<0.001). The mediastinal displacement in thex, Y and Z directions had no statistical significance regarding resection site ( P=0.355, 0.239 and 0.256) and operation mode ( P=0.241, 0.110 and 0.064). Comparative analysis of modified whole group mediastinal shift> and cut-off values, medium-simulation (m-S) and the originally planned radiotherapy shown that there was no significant difference in the incidence of radiation esophagitis (RE) and radiation pneumonitis in PORT patients (all P>0.05); however, the incidence of ≥grade 3 RE in the modified plan after m-S was significantly lower than that in the originally planned PORT patients, which were 0 and 7%, respectively ( P<0.001). Conclusions:Mediastinal displacement exists in the PORT process of N 2 or/and R 1-2 cases after radical operation of NSCLC, and obvious movement occurs in 20%-30% of patients. Relocating and modifying the target volume and radiotherapy plan in the middle of the PORT process is beneficial to quality assurance and quality control.
RESUMO
Neoadjuvant chemotherapy followed by surgery (NCS) is a common therapy pattern of non-small cell lung cancer (NSCLC). However, patients treated with NCS still suffer from relatively high locoregional recurrence. Postoperative radiotherapy (PORT) plays an important role in improving locoregional control, whereas its effect on survival remains controversial. Some studies propose that PORT yields no survival benefits for stage Ⅱ-Ⅲ A(N 2) patients treated with NCS, whereas other researches indicate that PORT can bring survival benefits for high-risk patients. The indications of PORT include R 1/R 2 resection and ypN 2. PORT is recommended with three-dimensional conformal therapy (3D-CRT) or intensity-modulated radiotherapy (IMRT) within the dose range of 50-54 Gy (R 0 resection). The target volume is inconclusive and the irradiation range of mediastinum involving with the metastatic lymph node regions is recommended in many studies. The adverse effects of PORT are acceptable in most studies.Nevertheless, the evidence level of relevant studies is relatively low. These results remain to be clarified by prospective randomized clinical trials.