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Objective To explore the dosimetric difference between different radiotherapy technologies in the treatment of early peripheral stage non?small ?cell lung cancer ( NSCLC ) . Methods Four?dimensional computed tomography scans and delineation of target volumes and organs at risk ( OARs) were performed in 5 patients pathologically diagnosed with stage T1/T2 peripheral NSCLC who were admitted from 2014 to 2015. Target volumes contained gross tumor volume (GTV), internal target volume (ITV), and planning target volume (PTV). ITV was contoured on the maximum intensity projection images. PTV was defined as ITV plus a 5 mm margin. OARs contained the heart, lung, esophagus, and spinal cord. The Monaco 5. 0 treatment planning system was used to design three plans. The three?dimensional conformal radiotherapy (3DCRT) plan had 11 fields in the diseased lung covering the PTV plus a 0. 2 cm margin. The sliding window intensity?modulated radiotherapy ( SW?IMRT ) plan had 9 fields in the same areas as the 3DCRT plan. The volumetric modulated arc therapy ( VMAT) plan had the gantry rotating 180° around the diseased lung. The evaluation criteria referred to the RTOG 0618 trial. Comparison was made by paired t test. Results The SW?IMRT plan had a significantly better homogeneity index than the 3DCRT plan ( 1. 03 vs. 1. 24,P= 0. 017 ) . Compared with the VMAT plan, the mean monitor units in the 3DCRT plan was significantly reduced by 24. 5%( P=0. 022) . The V30 and V40 of the 3DCRT plan were significantly reduced by 29. 4% and 28. 4%, respectively, compared with the SW?IMRT plan ( P=0. 003,0. 006) and 56. 7%and 59. 7%, respectively, compared with the VMAT plan ( P=0. 041,0. 019) . Conclusions 3DCRT may be an appropriate radiotherapy method for early stage NSCLC.
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ObjectiveTo further evaluate the value of the stereotactic gamma-ray body radiation therapy ( γ-SBRT ) for patients with stage Ⅰ / Ⅱ non-small cell lung cancer ( NSCLC ) basing on the preliminary studies.MethodsTwenty-nine eligible patients with stage Ⅰ / Ⅱ NSCLC who is unable or unwilling to receive surgery underwent treatment prospectively with γ-SBRT (OUR-QGD).Patients were fixed by vacuum bag.Each patient underwent slow CT simulation at 5 s/slide with thickness of 5 mm and interval of 5 mm to take into consideration tumor motion.A total dose of 50 Gy was delivered at 5 Gy/fraction to 50％ isodose line covering 100％ of the PTV,with 60 Gy at 6 Gy/fraction to 60％ isodose line covering 90％ of the CTV,70 Gy at 7 Gy/fraction to 70％ isodose line covering 80％ of the GTV,and 10 times finished in 2 weeks,5 fractions per week.ResultsThe follow-up rate was 97％.The 6 month local tumor response rate was 93％,with CR 86％,and PR 7％.The 1-,2-year local control rates were both 93％.The 1-,2-year overall survival rates for the whole group,stage Ⅰ and stage Ⅱ were 97％ and 89％,100％ and 92％,67％ and 67％,respectively.The 1-,2-year progression-free survival were 90％ and 86％,respectively.34％ of the patients had acute radiation toxicities ( grade 1,2 and 3 in 6,2 and 2patients,respectively),and 38％ late radiation toxicities ( grade 1 and 2 in 10 and 1,patients).Conclusions γ-SBRT is a safe and effective treatment regimen,resulted in promising local control and survival with minor toxicity.