Search

It is desirable to estimate the degree of the decrease in pulmonary function before lung stereotactic body radiation therapy (SBRT) especially for patients with poor pulmonary function. The purpose of this study was to investigate whether decreases in pulmonary function after SBRT may be predicted from radiation dose-volume parameters. A total of 70 patients undergoing SBRT were evaluated for changes in pulmonary function. Of these, 67 had primary lung cancer and 3 had lung metastasis. Twenty-six (37%) patients had chronic obstructive pulmonary disease. Pulmonary function tests (PFTs) were performed shortly before and at 18-24 months after SBRT. Radiation pneumonitis was Grade 2 in 10 patients and Grade 3 in 1. Mean forced vital capacity (FVC) decreased from 2.67 to 2.51 L (P < 0.01) and mean forced expiratory volume in 1 s (FEV1) decreased from 1.80 to 1.72 L (P < 0.01). Planning target volume (PTV) was correlated with changes in FVC. Changes in percent predicted FVC were correlated with %V5Gy (% of lung volume receiving > 5 Gy) and %V40Gy. Although the correlation was not significant, the %V20Gy value was the closest to the percent reduction in predicted FVC; %V20Gy of 10% tended to be associated with ~10% reduction in predicted FVC. Patients with poor pulmonary function did not necessarily show greater decreases in each PFT parameter. Decreases in FVC and FEV1 were within previously reported ranges. PTV was associated with decreases in FVC. The %V20Gy value was closest to the percentage decrease in predicted FVC., (© The Author(s) 2021. Published by Oxford University Press on behalf of The Japanese Radiation Research Society and Japanese Society for Radiation Oncology.)

Background: This study evaluated the safety and efficacy of repeat SBRT for local recurrence of stage I non-small-cell lung cancer (NSCLC) and solitary lung metastasis., Methods: Thirty-one patients with in-field local relapse of NSCLC (n = 23) or lung metastasis (n = 8) underwent repeat SBRT. All patients had grade 2 or lower radiation pneumonitis after the first SBRT. Local recurrence was diagnosed with CT and FDG-PET in 17 patients and by biopsy in 14. The median interval between the first and second SBRT was 18 months (range, 4-80). The first SBRT dose was mainly 48-52 Gy in 4 fractions (n = 25) according to the institutional protocols. Second SBRT doses were determined based on the tumor size and distance to organs at risk, and were mostly 48-52 Gy in 4 fractions (n = 13) or 60 Gy in 8 fractions (n = 13)., Results: At 3 years, overall survival and local control rates were 36 and 53%, respectively, for all 31 patients. Four patients showed no further recurrence for > 5 years (63-111 months) after the second SBRT. Radiation pneumonitis after the second SBRT was grade 2 in 4 patients, and no grade 3 pneumonitis was observed., Conclusion: Repeat SBRT was safe. Local control and survival rates were higher than expected. SBRT should be an important treatment option for local recurrence of NSCLC or lung metastasis after previous local SBRT., Trial Registration: This retrospective study was approved by the ethics committee of our institution (September, 2017; approval number: 27-10).

Background: After stereotactic body radiotherapy (SBRT) to the lung, radiation pneumonitis and fibrotic changes often develop, and the tumor shadow usually becomes indistinguishable from the fibrotic shadow. Occasionally, however, a residual mass in patients with no or mild radiation pneumonitis will be observed on serial computed tomography (CT) scans. The purpose of the present study was to evaluate the fate of such residual masses and, if possible, to determine the types of tumor at increased risk of local recurrence., Patients and Methods: A total of 50 patients (underlying disease: primary lung cancer in 45, local recurrence in 2, and metastasis in 3) were selected because they had been followed up for > 2 years or until death and had observable CT changes and measurable tumor size for > 1 year, regardless of the influence of radiation pneumonitis. The patients' outcomes were compared according to various patient and tumor characteristics, including the presence and absence of emphysema, tumor size, and tumor shrinkage rate. The median follow-up period was 52 months., Results: Of the 50 patients, only 8 developed local recurrence. The local control rate was 81% at 3 years and 73% at 5 years. The local control rates were similar between patients with a high tumor shrinkage rate and those with a low rate. The patients with emphysema exhibited a lower local control rate., Conclusion: The persistence of lung masses for > 1 year after SBRT is not necessarily indicative of an increased risk of local recurrence. A low tumor shrinkage rate also was not predictive of recurrence., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Introduction: Although the protocol of 48 Gy in four fractions over 4 days has been most often employed in stereotactic body radiotherapy (SBRT) for stage I non-small-cell lung cancer in Japan, higher doses are necessary to control larger tumors, and interfraction intervals should be longer than 24 hours to take advantage of reoxygenation. We report the final results of our study testing the following regimen: for tumors less than 1.5, 1.5-3, and greater than 3 cm in diameter, 44, 48, and 52 Gy, respectively, were given in four fractions with interfraction intervals of greater than or equal to 3 days., Methods: Among 180 histologically proven patients entered, 120 were medically inoperable and 60 were operable. The median patient age was 77 years (range, 29-89). SBRT was performed with 6-MV photons using four noncoplanar and three coplanar beams. Isocenter doses of 44, 48, and 52 Gy were given to four, 124, and 52 patients, respectively., Results: The 5-year overall survival rate was 52.2% for all 180 patients and 66% for 60 operable patients. The 5-year local control rate was 86% for tumors less than or equal to 3 cm (44/48 Gy) and 73% for tumors greater than 3 cm (52 Gy; p = 0.076). Grade greater than or equal to 2 radiation pneumonitis developed in 13% (10% for the 44/48-Gy group and 21% for the 52-Gy group; p = 0.056). Other grade 2 toxicities were all less than 4%., Conclusions: Our first prospective SBRT study yielded reasonable local control and overall survival rates and acceptable toxicity. Refinement of the protocol including dose escalation may lead to better outcome.

Background: The most common regimen of stereotactic body radiotherapy (SBRT) for stage I nonsmall cell lung cancer in Japan is 48 grays (Gy) in 4 fractions over 4 days. Radiobiologically, however, higher doses are necessary to control larger tumors, and interfraction intervals should be >24 hours to take advantage of reoxygenation. In this study, the authors tested the following regimen: For tumors that measured <1.5 cm, 1.5 to 3.0 cm, and >3.0 cm in greatest dimension, radiation doses of 44 Gy, 48 Gy, and 52 Gy, respectively, were given in 4 fractions with interfraction intervals of ≥3 days., Methods: Among 180 patients with histologically proven disease who entered the study, 120 were medically inoperable, and 60 were operable. The median patient age was 77 years (range, 29-92 years). SBRT was performed with 6-megavolt photons using 4 noncoplanar beams and 3 coplanar beams. Isocenter doses of 44 Gy, 48 Gy, and 52 Gy were received by 4 patients, 124 patients, and 52 patients, respectively., Results: The overall survival rate for all 180 patients was 69% at 3 years and 52% at 5 years. The 3-year survival rate was 74% for operable patients and 59% for medically inoperable patients (P = .080). The 3-year local control rate was 86% for tumors ≤3 cm (44/48 Gy) and 73% for tumors >3 cm (52 Gy; P = .050). Grade ≥2 radiation pneumonitis developed in 13% of patients (10% of the 44-Gy/48-Gy group and 21% of the 52-Gy group; P = .056). All other grade 2 toxicities developed in <4% of patients., Conclusions: The SBRT protocol used in this study yielded reasonable local control and overall survival rates and acceptable toxicity. Dose escalation is being investigated., (Copyright © 2011 American Cancer Society.)

Purpose: To investigate the relationship between waiting time (WT) and disease progression in patients undergoing stereotactic body radiotherapy (SBRT) for lung adenocarcinoma (AD) or squamous cell carcinoma (SQ)., Methods and Materials: 201 patients with Stage I AD or SQ undergoing SBRT between January 2004 and June 2010 were analyzed. The WT was defined as the interval between diagnostic computed tomography before referral and computed tomography for treatment planning or positioning before SBRT. Tumor size was measured on the slice of the longest tumor diameter, and tumor volume was calculated from the longest diameter and the diameter perpendicular to it. Changes in tumor volume and TNM stage progression were evaluated, and volume doubling time (VDT) was estimated., Results: The median WT was 42 days (range, 5-323 days). There was a correlation between WT and rate of increase in volume in both AD and SQ. The median VDTs of AD and SQ were 170 and 93 days, respectively. Thirty-six tumors (23%) did not show volume increase during WTs >25 days. In 41 patients waiting for ≤4 weeks, no patient showed T stage progression, whereas in 25 of 120 (21%) patients waiting for >4 weeks, T stage progressed from T1 to T2 (p = 0.001). In 10 of 110 (9.1%) T1 ADs and 15 of 51 (29%) T1 SQs, T stage progressed (p = 0.002). N stage and M stage progressions were not observed., Conclusion: Generally, a WT of ≤4 weeks seems to be acceptable. The WT seems to be more important in SQ than in AD., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: In stereotactic body radiotherapy (SBRT) for lung tumors, reducing tumor movement is necessary. In this study, we evaluated changes in tumor movement and percutaneous oxygen saturation (SpO2) levels, and preliminary clinical results of SBRT using the BodyFIX immobilization system., Methods: Between 2004 and 2006, 53 consecutive patients were treated for 55 lesions; 42 were stage I non-small cell lung cancer (NSCLC), 10 were metastatic lung cancers, and 3 were local recurrences of NSCLC. Tumor movement was measured with fluoroscopy under breath holding, free breathing on a couch, and free breathing in the BodyFIX system. SpO2 levels were measured with a finger pulseoximeter under each condition. The delivered dose was 44, 48 or 52 Gy, depending on tumor diameter, in 4 fractions over 10 or 11 days., Results: By using the BodyFIX system, respiratory tumor movements were significantly reduced compared with the free-breathing condition in both craniocaudal and lateral directions, although the amplitude of reduction in the craniocaudal direction was 3 mm or more in only 27% of the patients. The average SpO2 did not decrease by using the system. At 3 years, the local control rate was 80% for all lesions. Overall survival was 76%, cause-specific survival was 92%, and local progression-free survival was 76% at 3 years in primary NSCLC patients. Grade 2 radiation pneumonitis developed in 7 patients., Conclusion: Respiratory tumor movement was modestly suppressed by the BodyFIX system, while the SpO2 level did not decrease. It was considered a simple and effective method for SBRT of lung tumors. Preliminary results were encouraging.