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Objective:To explore the feasibility of low-dose 4DCT scanning in simulation and target delineation for solitary pulmonary tumors (SPTs).Methods:23 patients with SPTs received 4DCT scanning simulation with the conventional scanning (CON), low voltage (LV), low current (LA) and low voltage combined with low current (LVA) in sequence. Based on the 4DCT images derived from the four sets of scanning parameters, the internal gross tumor volume (IGTV CON, IGTV V, IGTV A, IGTV VA) of SPTs were delineated and matched. Taking IGTV CON as reference, the tumor displacement and the centroid position of IGTV V, IGTV A and IGTV VA were compared with IGTV CON. The radiation doses under different scanning parameters were compared. Results:The volumes of IGTV CON, IGTV V and IGTV A were (12.26±12.30) cm 3, (12.21±12.16) cm 3 and (11.87±11.70) cm 3, respectively ( P=0.337). IGTV VA was (11.34±11.07) cm 3, significantly smaller than IGTV CON ( P=0.005). There was no significant difference in the centroid positions of IGTV CON, IGTV V, IGTV A and IGTV VA in three directions ( P=0.491, 0.360, 0.136). The Dice′s similarity coefficient (DSC VA) was significantly lower than DSC V and DSC A ( P=0.004, 0.030). The tumor displacement measured by the four sets of 4DCT images was similar in the LR direction ( P=0.470), and also in the AP direction ( P=0.108). For the displacement in the SI direction, LVA scanning was smaller than CON ( P=0.015). The radiation doses under four different scanning conditions were (397.0±140.3) mGy·cm, (175.0±61.8) mGy·cm, (264.8±95.3) mGy·cm and (116.8±41.2) mGy·cm, respectively ( P<0.001). Conclusions:LV or LA scanning exert no significant effect on the volume, centroid position of IGTV and the tumor displacement in 4DCT simulation for SPTs. The radiation dose that patients receive under LV and LV scanning is lower than that of CON. Consequently, LV or LA scanning is feasible in 4DCT simulation and target delineation for SPTs.
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Objective:To compare the incidence of radiation pneumonitis (RP) between lung cancer patients from the European, American and Asian regions.Methods:The studies related to lung cancer and RP were searched from PubMed, Embase, and Cochrane library. According to the different places where the studies were conducted, the searched studies were divided into two types: Asian studies and European, American and Australian studies. The incidence of RP between two regions was summarized. Studies related to dosimetry parameters were searched from PubMed database.Results:A total of 3, 190 patients from 14studies were included. Meta-analysis results showed that the incidence of ≥ grade 3 RP was similar in patients from Asia and Europe, America and Australia (4.9% vs. 4.6%, P=0.895), whereas the incidence of grade 5 RP in Asia was significantly higher than that in Europe, America and Australia (1.5% vs. 0.2%, P=0.002). Moreover, the lung irradiation dose received by the patients in the Asian group was relatively low. Lung V 20Gy dose limitation standard was reported in 21studies. Further analysis found no statistical significance in lung V 20Gy dose limitation standard between two regions ( P=0.440), and the standard in Asian studies is likely to be even stricter. Conclusions:The incidence of RP after chemoradiotherapy in lung cancer patients in Asia is relatively higher compared with those in Europe, America and Australia. The differences in dose limitation standard should be noted when the thoracic radiation regimen based solely on the data from foreign studies is applied to the patients in Asia.
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Objective To evaluate the incidence and risk factors of symptomatic radiation-induced lung toxicity (SRILT) in non-small cell lung cancer (NSCLC) patients treated with modern radiotherapy after surgery.Methods Clinical data of consecutive NSCLC patients treated with postoperative three-dimensional conformal or intensity-modulated radiotherapy in Cancer Hospital of Chinese Academy of Medical Sciences between November 2002 and December 2011 were retrospectively analyzed.According to the Common Terminology Criteria for Adverse Events (CTCAE,version 3.0),SRILT was defined as ≥ grade 2 radiationinduced lung toxicity.Potential clinical risk factors and dosimetric parameters for SRILT were evaluated using logistic regression model.Results Among 227 enrolled patients,190 cases underwent lobectomy and 37 patients received pneumonectomy.Twenty-three patients (10.1％) developed SRILT after lobectomy.Seventeen patients experienced grade 2 SRILT,5 cases of grade 3 SRILT and 1 case of grade 4 SRILT.Univariate analysis showed that postoperative concurrent chemoradiotherapy,relatively large PTV,mean lung dose and V20-V40 were significantly correlated with the incidence of SRILT (P=0.015,0.048 and＜0.001).Multivariate analysis demonstrated that postoperative concurrent chemoradiotherapy and V20 were significantly associated with the incidence of SRILT (P =0.017 and P =0.009).Conclusions The incidence of SRILT is relatively low in NSCLC patients after postoperative radiotherapy.Concurrent chemoradiotherapy and V20 are risk factors of SRILT.
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RTOG 0617 trial has indicated that no benefit can be obtained in the overall survival of locally advanced non-small cell lung cancer patients by improving the prescribed dose,which promotes the adjustments to the strategies of dose escalation.Currently,multiple studies have been designed to explore more effective approaches to boost dose,such as dose boosts based on increased 18FDG-uptake regions,simultaneous integrated boost intensity-modulated radiotherapy and modulation of dose fractions,which have achieved a series of progress.The widespread application of PET-CT and intensity-modulated radiotherapy offers broad space for the dose escalation and optimization.
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Objective@#To evaluate the incidence and risk factors of symptomatic radiation-induced lung toxicity (SRILT) in non-small cell lung cancer (NSCLC) patients treated with modern radiotherapy after surgery.@*Methods@#Clinical data of consecutive NSCLC patients treated with postoperative three-dimensional conformal or intensity-modulated radiotherapy in Cancer Hospital of Chinese Academy of Medical Sciences between November 2002 and December 2011 were retrospectively analyzed. According to the Common Terminology Criteria for Adverse Events (CTCAE, version 3.0), SRILT was defined as ≥grade 2 radiation-induced lung toxicity. Potential clinical risk factors and dosimetric parameters for SRILT were evaluated using logistic regression model.@*Results@#Among 227 enrolled patients, 190 cases underwent lobectomy and 37 patients received pneumonectomy. Twenty-three patients (10.1%) developed SRILT after lobectomy. Seventeen patients experienced grade 2 SRILT, 5 cases of grade 3 SRILT and 1 case of grade 4 SRILT. Univariate analysis showed that postoperative concurrent chemoradiotherapy, relatively large PTV, mean lung dose and V20- V40 were significantly correlated with the incidence of SRILT (P=0.015, 0.048 and<0.001). Multivariate analysis demonstrated that postoperative concurrent chemoradiotherapy and V20 were significantly associated with the incidence of SRILT (P=0.017 and P=0.009).@*Conclusions@#The incidence of SRILT is relatively low in NSCLC patients after postoperative radiotherapy. Concurrent chemoradiotherapy and V20 are risk factors of SRILT.
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RTOG 0617 trial has indicated that no benefit can be obtained in the overall survival of locally advanced non-small cell lung cancer patients by improving the prescribed dose, which promotes the adjustments to the strategies of dose escalation. Currently, multiple studies have been designed to explore more effective approaches to boost dose, such as dose boosts based on increased 18FDG-uptake regions, simultaneous integrated boost intensity-modulated radiotherapy and modulation of dose fractions, which have achieved a series of progress. The widespread application of PET-CT and intensity-modulated radiotherapy offers broad space for the dose escalation and optimization.
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Chemoradiation has been the standard treatment of stage Ⅲ unresectable non-small cell lung cancer (NSCLC) for a long period of time. However, the clinical efficacy of chemoradiation has not been significantly improved in recent two decades. In the past 2-3 years, the role of immune-checkpoint inhibitors in metastatic NSCLC has been persistently strengthened. Moreover, the synergistic effect between radiotherapy and immune-checkpoint blockade has been conformed in pre-clinical and clinical studies. Recent clinical trials have demonstrated that the combination of radiotherapy and immune-checkpoint blockade has been proven to be more effective in the treatment of stage Ⅲ unresectable NSCLC. In this article, the latest clinical studies since 2017 regarding the application value of this combined treatment of stage Ⅲ unresectable NSCLC were summarized.
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Radiotherapy is an indispensable treatment of lung cancer. However, movement of lung cancer brings challenges to precise radiotherapy. Four-dimensional cone-beam CT is a four-dimensional imaging technique, which can demonstrate the tumor trajectory to improve the accuracy of radiotherapy. In this article, the research status and development tendency of four-dimentional cone-beam CT in terms of measuring and correcting set-up errors, observing variability of tumor postion and movement, guiding delineation of target volumes as well as calculating radiation dose were retrospectively reviewed.
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Objective KV-CBCT was utilized to evaluate the setup errors in lung SBRT with R624-SCF immobilization equipment,quantitatively analyze the percentage of all types of errors in the cumulative errors and unravel the main sources of setup errors.Methods The CBCT data weekly and QA data monthly from 32 patients diagnosed with lung neoplasms were collected to quantitatively analyze the setup errors.The cumulative errors were calculated by statistical model.The proportion and source of each type of setup error was analyzed.Results All 32 patients received a total of 420 times of CBCT.The setup errors of immobilization equipment in the lateral,supine-inferior,anterior-posterior directions were (0.03±0.72) mm,(0.73± 1.16) mm and (0.21±0.95) mm,respectively.The errors of tumor motion in three directions were (0.71±2.61) mm,(-0.80±2.60) mm and (0.075± 1.77) mm,respectively.According to the calculation formula proposed by Vance Keeling,the proportion of the cumulative error was 54.55％,9.21％ for immobilization equipment,12.97％ for tumor motion,2.55％ for couch sagging,5.70％ for Gantry radiation isocenter,4.73％ for Collimator radiation isocenter,4.61％ for couch radiation isocenter and 5.70％ for Xray field isocenter,respectively.Conclusions The main factors of setup errors during SBRT treatment for lung cancer are setup random,tumor motion,immobilization equipment,couch sagging and machine isocenter.During radiotherapy,targeted control of tumor motion is of significance for minimizing the cumulative errors.
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Objective To clarify the significance of chest radiotherapy in the treatment of oligometastatic stage Ⅳ non-small cell lung cancer ( NSCLC ) and to explore the optimal time of interventional therapy during chest radiotherapy. Methods A total of 192 patients with oligometastatic stage Ⅳ NSCLC admitted to Shanxi Provincial Cancer Hospital from 2008 to 2014 were randomly and evenly divided into the chemotherapy alone, radiotherapy+ early intervention, radiotherapy+ middle intervention and radiotherapy+ late intervention groups. Survival analysis was performed with Kanplan-Meier method. Results The median survival of 192 patients with oligometastatic stage Ⅳ NSCLC was 14. 50 months, and the 1-,2-and 3-year survival rates were 57. 4％,24. 0％ and 10. 7％, respectively. The median survivalin the chemotherapy alone, radiotherapy+ early intervention, radiotherapy+ middle intervention and radiotherapy+late intervention groups was 10,21,18 and 13 months, respectively. The 1-year survival rates were 34％, 73％,71％ and 51％,10％,40％,32％ and 13％ for the 2-year survival rates, and 0％,24％,16％ and 3％for the 3-year survival rates ( P=0. 000) . The median survival of patients with radiotherapy dose ≥ 60 Gy and< 60 Gy was 21 and 13 months, 76％ and 53％ for the 1-year survival rates, 34％ and 21％ for the 2-year survival rates, and 17％ and 10％ for the 3-year survival rates ( P=0. 002 ) . Conclusion Early interventional therapy and high-dose radiotherapy can improve the local control rate and prolong the survival time of patients with oligometastatic stage Ⅳ NSCLC.
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Objective To assess and delineate the dosimetric shortcomings of conventional radiotherapy planning,as compared with the three dimensional treatment planning system, and to obtain a better technique in the treatment of lung cancers.Methods Thirteen patients with stage ⅢA ⅢB non small cell lung cancer were chosen in the present study. Using the Cadplan 6.0.8 treatment planning system , three different methods of radiotherapy planning: conventional planning, conventional and conformal planning, and conformal planning were designed for each patient. The total radiation dose was 66 ?Gy and DVHs were used to assess the dosimetric distribution in the gross tumor volume and the surrounding organs at risk. Results No significant dosimetric disparity in the target volume was found among the three designs, according to anticipated therapeatic requirements. The conformity indices were 0.13,0.24 and 0.35 for these three radiotherapy designs. The mean lung volumes which received radiation dose of≥20?Gy were 32%,26% and 25%.The mean maximum dose at the spinal cord were 42?Gy,49?Gy and 33?Gy.The mean esophageal volume which received radiation of ≥50?Gy were 32%,34% and 22%, and the mean radiation dose to the heart were 18?Gy,15?Gy and 12?Gy,respectively. Conclusions Conventional radiotherapy planning is able to meet the demands of dosimetric requirements for radiation treatment of lung cancers. The three dimensional conformal radiation therapy planning system is able to provide superior delivery of high dose to the target volume without inflicting too high a risk to the surrounding normal tissues and organs.