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Backgound: We retrospectively investigated the clinical characteristics and outcome of pneumothorax after stereotactic body radiotherapy (SBRT) for lung tumors., Methods: Between April 2003 and July 2012, 473 patients with lung tumors were treated with SBRT. We identified 12 patients (2.5 %) with pneumothorax caused by SBRT, and evaluated the clinical features of pneumothorax., Results: All of the tumors were primary lung cancers. The severity of radiation pneumonitis was grade 1 in 10 patients and grade 2 in two patients. Nine patients had emphysema. The planning target volume and pleura overlapped in 11 patients, and the tumors were attached to the pleura in 7 patients. Rib fractures were observed in three patients before or at the same time as the diagnosis of pneumothorax. The median time to onset of pneumothorax after SBRT was 18.5 months (4-84 months). The severity of pneumothorax was grade 1 in 11 patients and grade 3 in one patient., Conclusion: Although pneumothorax was a relatively rare late adverse effect after SBRT, some patients demonstrated pneumothorax after SBRT for peripheral lung tumors. Although most pneumothorax was generally tolerable and self-limiting, careful follow-up is needed.

Background: Pathological diagnosis of small lung lesions is sometimes difficult in medically inoperable patients. The purpose of this study was to evaluate the adverse events and the outcomes of stereotactic body radiation therapy (SBRT) for lung lesions which were clinically diagnosed as primary lung cancer without pathological confirmation., Methods: Between April 2003 and April 2011, 88 patients with small lung lesions which were clinically diagnosed as primary lung cancer were treated with SBRT. The median tumor size was 19 mm (range 8-40 mm). The radiation dose was 48 Gy in four fractions in all patients. The median follow-up was 23 months (range 6-91 months)., Results: Recurrence was observed in 13 patients. The local control rate, progression-free survival rate, and overall survival rate at 3 years were 90, 67, and 80 %, respectively. Two patients (2.3 %) had Grade 2 radiation pneumonitis, and six patients (6.8 %) had Grade 2 rib fractures. There were no adverse events of Grade 3 or greater., Conclusions: SBRT appears to be a safe and effective treatment option for small lung lesions that are clinically diagnosed as primary lung cancer without pathological confirmation.

Aim: To retrospectively evaluate the efficacy and safety of definitive fractionated re-irradiation for local recurrence following stereotactic body radiotherapy (SBRT) for primary lung cancer., Patients and Methods: Between April 2003 and December 2011, 398 patients with primary lung tumor underwent SBRT at the Kyushu University Hospital, and 46 out of these developed local recurrence after SBRT. Definitive fractionated re-irradiation was performed for 17 out of the 46 patients. The median dose of re-irradiation was 60 Gy/ 30 fractions. Concurrent chemotherapy was given to four patients., Results: The median follow-up duration was 12.6 months. At one year post-re-irradiation, local progression-free survival was 33.8%; progression-free survival, 30.9%; cause-specific survival, 79.3%; and overall survival, 74.7%. No severe adverse events were observed during the follow-up., Conclusion: Definitive fractionated re-irradiation is thought to be a safe alternative therapy for local recurrence following SBRT, although its efficacy may be not entirely satisfactory.

Purpose: The purpose of this study was to clarify the incidence, the clinical risk factors, and the dose-volume relationship of radiation-induced rib fracture (RIRF) after hypofractionated stereotactic body radiation therapy (SBRT)., Methods and Materials: One hundred sixteen patients treated with SBRT for primary or metastatic lung cancer at our institution, with at least 6 months of follow-up and no previous overlapping radiation exposure, were included in this study. To determine the clinical risk factors associated with RIRF, correlations between the incidence of RIRF and the variables, including age, sex, diagnosis, gross tumor volume diameter, rib-tumor distance, and use of steroid administration, were analyzed. Dose-volume histogram analysis was also conducted. Regarding the maximum dose, V10, V20, V30, and V40 of the rib, and the incidences of RIRF were compared between the two groups divided by the cutoff value determined by the receiver operating characteristic curves., Results: One hundred sixteen patients and 374 ribs met the inclusion criteria. Among the 116 patients, 28 patients (46 ribs) experienced RIRF. The estimated incidence of rib fracture was 37.7% at 3 years. Limited distance from the rib to the tumor (<2.0 cm) was the only significant risk factor for RIRF (p = 0.0001). Among the dosimetric parameters used for receiver operating characteristic analysis, the maximum dose showed the highest area under the curve. The 3-year estimated risk of RIRF and the determined cutoff value were 45.8% vs. 1.4% (maximum dose, ≥42.4 Gy or less), 51.6% vs. 2.0% (V40, ≥0.29 cm(3) or less), 45.8% vs. 2.2% (V30, ≥1.35 cm(3) or less), 42.0% vs. 8.5% (V20, ≥3.62 cm(3) or less), or 25.9% vs. 10.5% (V10, ≥5.03 cm(3) or less)., Conclusions: The incidence of RIRF after hypofractionated SBRT is relatively high. The maximum dose and high-dose volume are strongly correlated with RIRF., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: The efficacy of stereotactic body radiation therapy (SBRT) for patients treated with domiciliary oxygen therapy is not well-known., Patients and Methods: We collected the clinical records of 15 patients with chronic respiratory insufficiency requiring domiciliary oxygen therapy at 1-3 l/min who were treated with SBRT for stage I non-small cell lung cancer. All patients were fixed with a thermoplastic body cast system. SBRT was given in 7-8 fields with an isocenter dose of 40-60 Gy in 4-10 fractions (median, 48 Gy in 4 fractions)., Results: The overall 2-year and 5-year survival rates for all patients were 67.4% and 34.7%, while the disease-specific 2-year and 5-year survival rates were 90.0% and 72.0%, respectively. Pulmonary adverse effects were mild in the majority of the patients, although two patients had grade 2 radiation pneumonitis. The oxygen flow required increased slightly at follow-up periods greater than one year, but was still at an acceptable level., Conclusion: SBRT was feasible for patients requiring domiciliary oxygen therapy.