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1.
John A. Kalapurakal Bryan Lee Jonathan Bautista Cynthia Rigsby Irene Helenowski Mahesh Gopalakrishnan 《Practical radiation oncology》2019,9(1):e62-e73
Purpose
Cardiac-sparing whole lung intensity modulated radiation therapy (WL IMRT) has been shown to improve cardiac protection and lung volume dose coverage compared with standard anteroposterior techniques. This dosimetry study had 2 aims: To determine the dosimetric advantages of a modified WL IMRT (M-WL IMRT) technique, designed to reduce radiation exposure to the thyroid gland and breast tissues, compared with standard WL IMRT (S-WL IMRT) and to determine the dosimetric advantages of M-WL IMRT and dosimetrically matched abdomen and flank radiation therapy (RT) fields designed to reduce normal tissue exposure compared with standard field matching techniques.Methods and materials
Computed tomography scans of the chest and abdomen that were obtained during computed tomography simulation of 10 female children were used. For Aim 1, for S-WL IMRT, the planning target volume (PTV) was obtained with a 1-cm expansion of the 4-dimensional lung volume (internal target volume). For M-WL IMRT, the PTV was reduced around the breast and thyroid gland to facilitate thyroid and breast sparing. For Aim 2, standard matching techniques for 3-dimensional anterior/posterior-posterior/anteriorwhole lung and abdominal RT fields were compared with a new dosimetric matching technique for WL IMRT and abdomen and flank fields. For both aims, the dose coverage of the lungs and radiation exposure to normal tissues (heart, thyroid, breasts) were statistically compared.Results
Compared with S-WL IMRT, the M-WL IMRT technique provided similar lung PTV dose coverage and a significantly superior reduction in mean breast and thyroid doses, without compromising cardiac protection. The M-WL IMRT technique combined with a dosimetrically matched abdomen and flank fields showed significantly superior normal tissue protection compared with standard matched anterior/posterior-posterior/anteriorlung and abdomen and flank RT fields.Conclusions
This study has shown that the M-WL IMRT technique can reduce radiation exposure to the thyroid gland and breast tissue without compromising cardiac protection and 4-dimensional lung volume dose coverage. This report also describes a new dosimetric matching technique between WL IMRT and abdomen and flank fields that will improve normal tissue sparing compared with standard techniques. 相似文献2.
Benjamin Foster Kunal Sindhu Jaroslaw Hepel David Wazer Theresa Graves Charu Taneja Doreen Wiggins Kara Leonard 《Practical radiation oncology》2019,9(2):e134-e141
Purpose
BioZorb® (Focal Therapeutics, Aliso Viejo, CA) is an implantable 3-dimensional bioabsorbable marker used for tumor bed volume (TBV) identification during postoperative radiation therapy (RT) planning. We aimed to calculate and compare RT TBVs between two cohorts managed with and without the device.Methods and Materials
Data from patients with breast cancer who were treated at Rhode Island Hosptial, Providence RI between May 1, 2015 and April 30, 2016 were retrospectively reviewed and grouped based on 3-dimensional bioabsorbable marker placement. Pathology reports were used to calculate tumor excision volume (TEV) after breast conservation. Specifically, the three dimensions provided were multiplied to generate a cubic volume, defined as TEV. TBV was calculated using treatment volumes generated with Philips Pinnacle3 treatment planning software (Andover, MA). Linear regression analyses assessed the relationship between excised TEV and TBV. T tests compared the slopes of the best fit lines for plots of TEV versus TBV.Results
In this retrospective case-control study, 116 patients undergoing breast RT were identified; of whom 42 received a 3-dimensional bioabsorbable marker and 74 did not. The mean TEVs were 102.7 cm3 with the device and 103.2 cm3 without the device, and the mean TBVs for the same groups were 27.5 cm3 and 40.1 cm3, respectively. The TBV standard errors for patients who did and did not receive 3-dimensional bioabsorbable markers were 23.739 and 38.685, respectively. The t tests found the slopes of the lines of best fit for these cohorts to be statistically significantly different (P = .001), with smaller TBVs achieved with 3-dimensional bioabsorbable marker placement.Conclusions
When comparing TBVs between patients contemporaneously treated with or without a 3-dimensional bioabsorbable marker, device placement was associated with statistically significantly smaller TBVs in the setting of similar TEVs. 相似文献3.
Christopher Chipko Julius Ojwang Leila Rezai Gharai Xiaoyan Deng Nitai Mukhopadhyay Elisabeth Weiss 《Practical radiation oncology》2019,9(3):e338-e346
PurposeChest wall (CW) pain and rib fractures are frequently diagnosed after stereotactic body radiation therapy (SBRT) for malignant lung tumors. We hypothesize that multiple risk factors, including bone mineral density (BMD), are associated with CW toxicity, and that CW pain and rib fractures often evolve into chronic clinical problems.Methods and materialsA total of 118 lung tumors treated with SBRT in 100 patients with a minimum follow-up period of 2 years were retrospectively analyzed. The incidence, clinical course, and related demographic, clinical, and dosimetric factors of CW pain and rib fractures were analyzed. In addition, BMD was assessed, and the radiographic appearance of radiation-induced rib fractures and their healing process were characterized.ResultsThe median follow-up was 49 months (range, 24-106 months). CW pain developed in 33 of 118 treatments (28%) after, on average, 12.5 months (range, 0-50 months), and was more common in women (P = .04). The mean duration of CW pain was 25 months (range, 2-63 months), and 36% of patients never had resolution of CW pain. A total of 34 of 118 treatments (29%) resulted in rib fractures at a mean time of 22 months (range, 3-46 months); rib fractures were more common in women, African Americans, upper/middle lobe tumors, and patients with lower BMD (P < .05). The mean duration of rib fractures was 25 months (range, 5-41 months), and only 16 rib fractures (47%) healed. Shorter CW planning target volume distance resulted in a higher risk for both rib fractures and CW pain (P = .01). Sixty-seven percent of fractures developed surrounding soft tissue fibrosis, and 62% (21 of 34 fractures) heterotopic ossification. Diabetes, body mass index, and steroid use were not associated with CW pain or rib fracture.ConclusionsSeveral factors were associated with a higher risk of SBRT-related CW toxicity. Optimal CW sparing (eg, volumetric modulated arc therapy, lower dose per fraction) should be considered in this patient group without compromising tumor control. SBRT-induced rib fractures commonly heal abnormally and result in potential chronic CW pain. 相似文献
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Yan Zhang Robert W. Mutter Sean S. Park Tina J. Hieken Elizabeth S. Yan Kimberly S. Corbin Debra H. Brinkmann Deanna H. Pafundi 《Practical radiation oncology》2019,9(1):e14-e21
Purpose
We investigated the feasibility and accuracy of using carbon fiducials to localize the lumpectomy cavity with 2-dimensional kV imaging for early stage breast cancer radiation therapy.Methods and Materials
Carbon fiducials were placed intraoperatively in the periphery of the lumpectomy cavity. Nine patients received whole breast irradiation with a boost, and 2 patients received 3-dimensional conformal partial breast irradiation. A total of 89 fractions were assessed for setup errors relative to a predefined gold standard, cone beam computed tomography (CBCT) match to the lumpectomy cavity, using the following 4 setup methods: (1) Align skin tattoos with lasers; (2) match bone with 2-dimensional–2-dimensional (2D/2D) kV onboard imaging (OBI); (3) match the whole breast with CBCT; and (4) match carbon fiducials with 2D/2D kV OBI. The margin for the planning target volume (PTV) was calculated by 2 standard deviations of the setup errors, and compared among the 4 setup methods. Setup errors for patients treated with free breathing and patients with deep inspiration breath hold were also compared.Results
The carbon fiducials were sufficiently visible on OBI for matching and introduced minimal artifacts. Of the 4 alignment methods, 2D/2D OBI match to fiducials resulted in the smallest setup errors. The PTV margin was 12 mm for aligning skin tattoos using lasers, 9.2 mm for matching bone on OBI, 6.5 mm for matching breast on CBCT, and 3.5 mm for matching fiducials on 2D/2D OBI. Compared with free breathing, deep inspiration breath hold generally reduced the standard deviations of the setup errors, but further investigation would be needed.Conclusions
Matching to carbon fiducials increased the localization accuracy to the lumpectomy cavity. This reduces residual setup error and PTV margins, facilitating tissue sparing without diminishing treatment efficacy. 相似文献5.
Lauren E. Henke Jessika A. Contreras Thomas Mazur Olga Green Nalini Daniel Hilary Lashmett Tammy Senter H. Michael Gach Laura Ochoa Sasa Mutic Imran Zoberi Jeffrey Bradley Clifford Robinson Maria A. Thomas 《Practical radiation oncology》2019,9(3):e298-e306
PurposeCardiac radiation is associated with cardiotoxicity in patients with thoracic and breast malignancies. We conducted a prospective study using cine magnetic resonance imaging (MRI) scans to evaluate heart motion. We hypothesized that cine MRI could be used to define population-based cardiac planning organ-at-risk volumes (PRV).Methods and MaterialsA total of 16 real-time acquisitions were obtained per subject on a 1.5 Tesla MRI (Philips Ingenia). Planar cine MRI was performed in 4 sequential sagittal and coronal planes at free-breathing (FB) and deep-inspiratory breath hold (DIBH). In-plane cardiac motion was assessed using a scale-invariant feature transformation–based algorithm. Subject-specific pixel motion ranges were defined in anteroposterior (AP), left-right (LR), and superoinferior (SI) planes. Averages of the 98% and 67% of the maximum ranges of pixel displacement were defined by subject, then averaged across the cohort to calculate PRV expansions at FB and DIBH.ResultsData from 20 subjects with a total of 3120 image frames collected per subject in coronal and sagittal planes at DIBH and FB, and 62,400 total frames were analyzed. Cohort averages of 98% of the maximum cardiac motion ranges comprised margin expansions of 12.5 ± 1.1 mm SI, 5.8 ± 1.2 mm AP, and 6.6 ± 1.0 mm LR at FB and 6.7 ± 1.5 mm SI, 4.7 ± 1.3 mm AP, and 5.3 ± 1.3 mm LR at DIBH. Margins for 67% of the maximum range comprised 7.7 ± 0.7 mm SI, 3.2 ± 0.6 mm AP, and 3.7 ± 0.6 mm LR at FB and 4.1 ± 0.9 mm SI, 2.7 ± 0.8 mm AP, and 3.2 ± 0.8 mm LR at DIBH. Subsequently, these margins were simplified to form PRVs for treatment planning.ConclusionsWe implemented scale-invariant feature transformation-based motion tracking for analysis of the cardiac cine MRI scans to quantify motion and create cohort-based cardiac PRVs to improve cardioprotection in breast and thoracic radiation. 相似文献
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Xiaoying Liang Dandan Zheng Maria Mamalui-Hunter Stella Flampouri Bradford S. Hoppe Nancy Mendenhall Zuofeng Li 《Practical radiation oncology》2019,9(1):38-48
Purpose
Using planning target volume (PTV) to account for setup uncertainties in stereotactic body radiation therapy (SBRT) of lung cancer has been questioned because a significant portion of the PTV contains low-density lung tissue. The purpose of this study is to (1) investigate the feasibility of using robust optimization to account for setup uncertainties in volumetric modulated arc therapy plan for lung SBRT and (2) evaluate the potential normal tissue–sparing benefit of a robust optimized plan compared with a conventional PTV-based optimized plan.Methods and materials
The study was conducted with both phantom and patient cases. For each patient or phantom, 2 SBRT lung volumetric modulated arc therapy plans were generated, including an optimized plan based on the PTV (PTV-based plan) with a 5-mm internal target volume (ITV)-to-PTV margin and a second plan based on robust optimization of ITV (ITV-based plan) with ±5-mm setup uncertainties. The target coverage was evaluated on ITV D99 in 15 scenarios that simulated a 5-mm setup error. Dose-volume information on normal lung tissue, intermediate-to-high dose spillage, and integral dose was evaluated.Results
Compared with PTV-based plans, ITV-based robust optimized plans resulted in lower normal lung tissue dose, lower intermediate-to-high dose spillage to the body, and lower integral dose, while preserving the dose coverage under setup error scenarios for both phantom and patient cases.Conclusions
Using ITV-based robust optimization, we have shown that accounting for setup uncertainty in SBRT planning is feasible. Further clinical studies are warranted to confirm the clinical effectiveness of this novel approach. 相似文献7.
Mehran Yusuf Jeremy Gaskins Paul Tennant Jeffrey Bumpous Neal Dunlap 《Practical radiation oncology》2019,9(4):e372-e385
PurposeThis study aimed to determine the impact of time to initiation (TTI) of adjuvant radiation therapy (RT) on overall survival (OS) for patients with stage I or II Merkel cell carcinoma (MCC).Methods and materialsThe National Cancer Database was queried for patients with MCC of the head and neck, trunk, or extremities diagnosed between 2006 and 2014. Patients who did not undergo resection or receive adjuvant RT within 180 days of surgery were excluded. TTI was defined as the time from resection to first RT fraction. Linear regression was used to define factors associated with TTI. Recursive partitioning analysis modeling was performed to determine an optimal threshold for TTI. Cox proportional hazards modeling was performed to define covariates associated with OS.ResultsA total of 2293 patients were included in this study. The median TTI for the cohort was 62 days (interquartile range, 43-86 days). TTI was not associated with OS for the overall cohort by multivariable Cox modeling (P = .19). Age, treatment facility type, lymph node examination, anatomic subsite, and surgical margin were associated with TTI (P < .05). Age, sex, insurance status, Charlson-Deyo comorbidity score, lymph node examination status, tumor size, and surgical margin were associated with OS (all P < .05).ConclusionsIncreased TTI of adjuvant RT was not associated with OS for patients with early stage MCC in this analysis of the National Cancer Database. The median TTI of 62 days from resection to adjuvant RT initiation for our study cohort contextualizes TTI on a national level and may offer reassurance for patients with prolonged postoperative wound healing or intercurrent illness delaying immediate RT initiation. Despite the lack of a clear detriment to survival with increased TTI up to 180 days from surgery, unnecessary delays in initiating adjuvant therapy should continue to be minimized while ensuring optimal recovery from resection. 相似文献
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Baoshe Zhang Sung-Woo Lee Shifeng Chen Jinghao Zhou Karl Prado Warren D&#x;Souza Byongyong Yi 《Practical radiation oncology》2019,9(1):49-54
Purpose
This study aimed to develop action levels for replanning to accommodate dosimetric variations resulting from anatomic changes during the course of treatments, using daily cone beam computed tomography (CBCT).Methods and materials
Daily or weekly CBCT images of 20 patients (10 head and neck, 5 lung, and 5 prostate cancers) who underwent resimulation per physicians' clinical decisions, mainly from the comparison of CBCT scans, were used to determine action levels. The first CBCT image acquired before the first treatment was used as the reference image to rule out effects of dose inaccuracy from the CBCT. The Pearson correlation of clinical target volume (CTV) was used as a parameter of anatomic variation. Parameters for action levels on dose and anatomic variation were deduced by comparing the parameters and clinical decisions made for replanning. A software tool was developed to automatically perform all procedures, including dose calculations, using the CBCT and plan evaluations.Results
Replans were clinically decided based on either significant dose or anatomic changes in 13 cases. The 7 cases that did not require replanning showed dose differences <5%, and the Pearson correlation of the CTV was >75% for all fractions. A difference in planning target volume dose >5% or a difference in the image correlation coefficient of the CTV <0.75 proved to be indicators for replanning. Once the results of the CBCT plan met the replanning criteria, the software tool automatically alerted the attending physician and physicist by both e-mail and pager so that the case could be examined closely.Conclusions
Our study shows that a dose difference of 5% and/or anatomy variation at 0.75 Pearson correlations are practical action levels on dose and anatomic variation for replanning for the given data sets. 相似文献10.
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Laura A. Dawson Kathryn A. Winter Alan W. Katz Michael C. Schell James Brierley Yuhchyau Chen Neil Kopek Christopher H. Crane Christopher G. Willett 《Practical radiation oncology》2019,9(4):e386-e393
PurposeThis study aimed to determine the feasibility and maximally tolerated dose of hypofractionated, conformal radiation therapy (RT) in patients with liver metastases.Methods and materialsNonsurgical patients with ≤5 liver metastases (sum of maximal diameter of all lesions ≤8 cm) were included in the study. There were 4 dose levels: 35 Gy, 40 Gy (starting level), 45 Gy, and 50 Gy, in 10 fractions. The clinical target volume included metastases identified on contrast computed tomography or magnetic resonance imaging with a 5-mm margin within the liver. The planning target volume margin ranged from 4 to 30 mm, depending on breathing motion. Dose-limiting toxicities were defined as RT-related grade ≥4 hepatic or gastrointestinal toxicities or thrombocytopenia occurring within 90 days of the start of RT.ResultsA total of 26 patients with metastases from colorectal (8 patients), breast (7 patients) and other malignancies (11 patients) were enrolled between November 2005 and December 2010. Twenty-three patients were evaluable (8, 7, and 8 on the 40, 45, and 50 Gy dose levels, respectively). Two patients assigned to 50 Gy received 35 Gy owing to normal tissue limits, so 2 additional patients were treated to 50 Gy. There were no dose-limiting toxicities on any of the dose levels. On the 45 Gy dose level, 1 patient developed reversible grade 3 enteritis (37 days from RT start) and diarrhea (22 days); another patient developed grade 3 lymphopenia (23 days). At the 50 Gy dose level, 1 patient had grade 3 hyperglycemia (74 days), and another patient developed grade 3 lymphopenia (13 days), colonic hemorrhage (325 days), and colonic gastrointestinal obstruction (325 days). With a potential median follow-up of 66.1 months (range, 34.6-89.0 months), no other late toxicities were observed.ConclusionsTreatment of liver metastases with 50 Gy in 10 fractions was feasible and safe in a multi-institutional setting. 相似文献
12.
Scott C. Morgan Karen Hoffman D. Andrew Loblaw Mark K. Buyyounouski Caroline Patton Daniel Barocas Soren Bentzen Michael Chang Jason Efstathiou Patrick Greany Per Halvorsen Bridget F. Koontz Colleen Lawton C. Marc Leyrer Daniel Lin Michael Ray Howard Sandler 《Practical radiation oncology》2018,8(6):354-360
Purpose
The aim of this guideline is to present recommendations regarding moderately hypofractionated (240-340 cGy per fraction) and ultrahypofractionated (500 cGy or more per fraction) radiation therapy for localized prostate cancer.Methods and Materials
The American Society for Radiation Oncology convened a task force to address 8 key questions on appropriate indications and dose-fractionation for moderately and ultrahypofractionated radiation therapy, as well as technical issues, including normal tissue dose constraints, treatment volumes, and use of image guided and intensity modulated radiation therapy. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and Society-approved tools for grading evidence quality and recommendation strength.Results
Based on high-quality evidence, strong consensus was reached for offering moderate hypofractionation across risk groups to patients choosing external beam radiation therapy. The task force conditionally recommends ultrahypofractionated radiation may be offered for low- and intermediate-risk prostate cancer but strongly encourages treatment of intermediate-risk patients on a clinical trial or multi-institutional registry. For high-risk patients, the task force conditionally recommends against routine use of ultrahypofractionated external beam radiation therapy. With any hypofractionated approach, the task force strongly recommends image guided radiation therapy and avoidance of nonmodulated 3-dimensional conformal techniques.Conclusions
Hypofractionated radiation therapy provides important potential advantages in cost and convenience for patients, and these recommendations are intended to provide guidance on moderate hypofractionation and ultrahypofractionation for localized prostate cancer. The limits in the current evidentiary base—especially for ultrahypofractionation—highlight the imperative to support large-scale randomized clinical trials and underscore the importance of shared decision making between clinicians and patients. 相似文献13.
Bindu V. Manyam Gregory M.M. Videtic Kyle Verdecchia Chandana A. Reddy Neil M. Woody Kevin L. Stephans 《Practical radiation oncology》2019,9(2):e187-e195
Purpose
Dosimetric parameters to limit chest wall toxicity (CWT) are not well defined in single-fraction (SF) stereotactic body radiation therapy (SBRT) phase 2 trials. We sought to determine the relationship of tumor location and dosimetric parameters with CWT for SF-SBRT.Methods and Materials
From a prospective registry of 1462 patients, we identified patients treated with 30 Gy or 34 Gy. Gross tumor volume was measured as abutting, ≤1 cm, 1 to 2 cm, or >2 cm from the chest wall. CWT was prospectively graded according to Common Terminology Criteria for Adverse Events version 3.0, with grade 2 requiring medical therapy, grade 3 requiring procedural intervention, and grade 4 being disabling pain. Grade 1 CWT or radiographic rib fracture was not included. Logistic regression analysis was used to identify the parameters associated with CWT and calculate the probability of CWT with dose.Results
This study included 146 lesions. The median follow-up time was 23.8 months. The 5-year local control, distant metastasis, and overall survival rates were 91.8%, 19.2%, and 28.7%, respectively. Grade 2 to 4 CWT was 30.6% for lesions abutting the chest wall, 8.2% for ≤1 cm from the chest wall, 3.8% for 1 to 2 cm from the chest wall, and 5.7% for >2 cm from the chest wall. Grade ≥3 CWT was 1.4%. Tumor abutment (odds ratio [OR]: 6.5; P = .0005), body mass index (OR: 1.1; P = .02), rib D1cc (OR: 1.01/Gy; P = .03), chest wall D1cc (OR: 1.08/Gy; P = .03), and chest wall D5cc (OR: 1.10/Gy; P = .01) were significant predictors for CWT on univariate analysis. Tumor abutment was significant for CWT (OR: 7.5; P = .007) on multivariate analysis. The probability of CWT was 15% with chest wall D5cc at 27.2 Gy and rib D1cc at 30.2 Gy.Conclusions
The rate of CWT with SF-SBRT is similar to the rates published for fractionated SBRT, with most CWT being low grade. Tumor location relative to the chest wall is not a contraindication to SF-SBRT, but the rates increase significantly with abutment. Rib D1cc and chest wall D1cc and D5cc may be used as predictors of CWT. 相似文献14.
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Nancy El-Bared Lorraine Portelance Benjamin O. Spieler Deukwoo Kwon Kyle R. Padgett Karen M. Brown Eric A. Mellon 《Practical radiation oncology》2019,9(1):e46-e54
Purpose
Magnetic resonance imaging guided (MRI-g) radiation therapy provides visualization of the target and organs at risk (OARs), allowing for daily online adaptive radiation therapy (OART). We hypothesized that MRI-g OART would improve OAR sparing and target coverage in patients with pancreatic cancer treated with stereotactic body radiation therapy (SBRT).Methods and Materials
Ten patients received pancreas SBRT to a dose of 33 to 40 Gy in 5 fractions. The dose was prescribed to 90% coverage of the planning target volume at 100% isodose (PTV100). After each fraction's setup magnetic resonance imaging scan, the target position was aligned by 3-dimensional shifts, the normal anatomy was recontoured, and the original radiation therapy plan was recalculated to create a nonadaptive plan. A reoptimized (adaptive) plan was then generated for each fraction and renormalized to 90% coverage of PTV100. Target and OAR doses between nonadaptive and adaptive plans were compared to assess the dosimetric impact of daily adaptation.Results
The PTV100 mean for adaptive and nonadaptive techniques was 90% and 80.4% (range, 46%-97%), respectively (P = .0008). Point maximum (Dmax) 38 Gy duodenum objectives were met in 43 adaptive fractions compared with 32 nonadaptive fractions (P = .022). Both PTV100 ≥90% and all OAR objectives were achieved in 28 adaptive fractions compared with only 3 nonadaptive fractions. For nonadaptive plans, interfraction increases in stomach volume correlated with higher stomach V33 (P = .004), stomach Dmax (P = .009), duodenum V33 (P = .021), and duodenum Dmax (P = .105). No correlation was observed between stomach volume and OAR doses for adaptive plans. OART plans with Dmax violations of the spinal cord (20 Gy) in 4 fractions and large bowel (38 Gy) in 5 fractions were identified (although not delivered).Conclusions
MRI-g OART improves target coverage and OAR sparing for pancreas SBRT. This benefit partially results from mitigation of interfraction variability in stomach volume. Caution must be exercised to evaluate all OARs near the treatment area. 相似文献16.
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Sean M. Parker R. Alfredo Siochi Sijin Wen Malcolm D. Mattes 《Practical radiation oncology》2019,9(1):e90-e97
Purpose
Stereotactic body radiation therapy (SBRT) is commonly used to treat primary or oligometastatic malignancies in the lung, but most of the available data that describe the safety and efficacy of SBRT are for smaller tumors. The purpose of this study was to evaluate the impact of tumor size, among other factors, on local control (LC) and radiation pneumonitis (RP) in patients who received lung SBRT.Methods and materials
This retrospective study included 144 patients with 100 primary (57.1%) and 75 metastatic (42.9%) lung tumors treated with SBRT between 2012 and 2018. Measurements of tumor size, treatment volume, histology, and radiation dose were evaluated for association with LC. Additional factors evaluated for association with the development of symptomatic RP included volume of the lung, heart, and central airway exposed to relevant doses of radiation.Results
The median follow-up time was 15.0 months (interquartile range, 8.0-26.0 months). LC rates at 12 and 24 months posttreatment were 95.1% and 92.7%, respectively. LC at 1 year was higher for tumors <5 cm in diameter than for tumors >5 cm in diameter (98.2% vs 79.8%, respectively; P < .01). On univariate analysis, LC was associated with a smaller gross tumor volume (GTV) diameter (P < .01), GTV volume (P < .01), planning target volume (PTV) diameter (P < .01), PTV volume (P < .01), and larger PTV-to-GTV ratio (P = .04). Tumor histology and treatment intent were not correlated with LC. RP was associated with a higher ipsilateral lung mean lung dose (P = .02), V2.5 (P = .03), V5 (P = .02), V13 (P = .03), V20 (P = .05), V30 (P = .02), V40 (P = .02), and V50 (P = .03), and several similar total lung dose parameters and heart maximum point dose (P = .02). The optimal mean ipsilateral lung dose cutoff predictive of RP was 8.6 Gy.Conclusions
A larger tumor size and smaller PTV-to-GTV ratio was associated with local recurrence of lung tumors treated with SBRT, but ipsilateral lung doses were most associated with symptomatic RP. 相似文献20.
Mark Sueyoshi Arthur J. Olch Kevin X. Liu Alisha Chlebik Desirae Clark Kenneth K. Wong 《Practical radiation oncology》2019,9(1):e110-e117
