Stereotactic body radiation therapy (SBRT) is increasingly being used to treat thoracic tumors. We attempted here to identify dose-volume parameters that predict chest wall toxicity (pain and skin reactions) in patients receiving thoracic SBRT.
We screened a database of patients treated with SBRT between August 2004 and August 2008 to find patients with pulmonary tumors within 2.5 cm of the chest wall. All patients received a total dose of 50 Gy in four daily 12.5-Gy fractions. Toxicity was scored according to the NCI-CTCAE V3.0.
Of 360 patients in the database, 265 (268 tumors) had tumors within <2.5 cm of the chest wall; 104 (39%) developed skin toxicity (any grade); 14 (5%) developed acute pain (any grade), and 45 (17%) developed chronic pain (Grade 1 in 22 cases [49%] and Grade 2 or 3 in 23 cases [51%]). Both skin toxicity and chest wall pain were associated with the V30, or volume of the chest wall receiving 30 Gy. Body mass index (BMI) was also strongly associated with the development of chest pain: patients with BMI≥29 had almost twice the risk of chronic pain (p=0.03). Among patients with BMI>29, diabetes mellitus was a significant contributing factor to the development of chest pain.
Safe use of SBRT with 50 Gy in four fractions for lesions close to the chest wall requires consideration of the chest wall volume receiving 30 Gy and the patient's BMI and diabetic state.
"Mutter and colleagues have recently demonstrated a significant increase in chest wall injury and pain syndrome driven by the volume of chest wall receiving 30 Gy (V30) (Mutter et al., 2012). Other investigators have demonstrated similar findings in retrospective review of radiosurgery treatment plans including issues associated with body habitus influencing treatment outcome (Voroney et al., 2009; Dunlap et al., 2010; Welsh et al., 2010). "
[Show abstract][Hide abstract] ABSTRACT: Purpose:
Chest wall pain and discomfort has been recognized as a significant late effect of radiation therapy in historical and modern treatment models. Stereotactic Body Radiotherapy (SBRT) is becoming an important treatment tool in oncology care for patients with intrathoracic lesions. For lesions in close approximation to the chest wall with motion management, SBRT techniques can deliver high dose to the chest wall. As an unintended target of consequence, there is possibility of imposing significant chest wall pain and discomfort as a late effect of therapy. The purpose of this paper is to evaluate the potential role of Volume Modulated Arc Therapy (VMAT) technologies in decreasing chest wall dose in SBRT treatment of pulmonary lesions in close approximation to the chest wall.
Materials and methods:
Ten patients with pulmonary lesions of various sizes and tomography in close approximation to the chest wall were selected for retrospective review. All volumes including tumor target, chest wall, ribs, and lung were contoured with maximal intensity projection maps and four-dimensional computer tomography planning. Radiation therapy planning consisted of static techniques including Intensity Modulated Radiation Therapy compared to VMAT therapy to a dose of 60 Gy in 12 Gy fraction dose. Dose volume histogram to rib, chest wall, and lung were compared between plans with statistical analysis.
In all patients, dose and volume were improved to ribs and chest wall using VMAT technologies compared to static field techniques. On average, volume receiving 30 Gy to the chest wall was improved by 74%; the ribs by 60%. In only one patient did the VMAT treatment technique increase pulmonary volume receiving 20 Gy (V20).
VMAT technology has potential of limiting radiation dose to sensitive chest wall regions in patients with lesions in close approximation to this structure. This would also have potential value to lesions treated with SBRT in other body regions where targets abut critical structures.
Frontiers in Oncology 02/2013; 3:12. DOI:10.3389/fonc.2013.00012
"The use of only three beams, distance from the tumour to the posterior chest wall skin of less than 5 cm and a maximum skin dose 50% of the prescribed dose were found to be risk factors for grade 2 or higher acute skin toxicity . In a study from MDACC, the volume of the chest wall receiving 30 Gy in four fractions predicted the risk of skin toxicity among patients with lung tumours within 2.5 cm from the chest wall . "
[Show abstract][Hide abstract] ABSTRACT: The clinical applications of stereotactic body radiotherapy or stereotactic ablative radiotherapy (SABR) for the treatment of primary and metastatic tumours of different organ sites have been expanding rapidly in the recent decade. SABR requires advanced technology in radiotherapy planning and image guidance to deliver a highly conformal ablative dose precisely to targets (or tumours) in the body. Although this treatment modality has shown promising results with regard to tumour control, some serious complications have been observed and reported. In order to achieve a favourable therapeutic ratio, strategies to mitigate the risk of complications must be in place. This overview will summarise the reported serious complications caused by SABR and strategies to mitigate the risk will be discussed.
"Typically, the lower prescription isodose line was chosen when the proximity of critical normal structures mandated a compromise to the PTV, and therefore a higher dose to the tumor center and sharper dose gradients were required. Normal tissue dose-volume constraints were based on BED calculations and our previous clinical findings of the toxicity of SABR [6,12,21] and are shown in Table 1. Violations to the constraints for the spinal cord, esophagus, and brachial plexus were not allowed; constraints on other normal tissues were judged on the basis of clinical target coverage. "
[Show abstract][Hide abstract] ABSTRACT: Stereotactic ablative radiotherapy (SABR) can achieve excellent local control rates in early-stage non-small cell lung cancer (NSCLC) and has emerged as a standard treatment option for patients who cannot undergo surgery or those with isolated recurrences. However, factors that may predict toxicity or survival are largely unknown. We sought here to identify predictors of survival and pneumonitis after SABR for NSCLC in a relatively large single-institution series.
Subjects were 130 patients with stage I NSCLC treated with four-dimensional computed tomography (4D CT) -planned, on-board volumetric image-guided SABR to 50 Gy in 4 fractions. Disease was staged by positron emission tomography/computed tomography (PET/CT) and scans were obtained again at the second follow-up after SABR.
At a median follow-up time of 26 months, the 2-year local control rate was 98.5%. The median overall survival (OS) time was 60 months, and OS rates were 93.0% at 1 year, 78.2% at 2 years, and 65.3% at 3 years. No patient experienced grade 4-5 toxicity; 15 had radiation pneumonitis (12 [9.3%] grade 2 and 3 [2.3%] grade 3). Performance status, standardized uptake value (SUV)max on staging PET/CT, tumor histology, and disease operability were associated with OS on univariate analysis, but only staging SUVmax was independently predictive on multivariate analysis (P = 0.034). Dosimetric factors were associated with radiation pneumonitis on univariate analysis, but only mean ipsilateral lung dose ≥9.14 Gy was significant on multivariate analysis (P = 0.005).
OS and radiation pneumonitis after SABR for stage I NSCLC can be predicted by staging PET SUVmax and ipsilateral mean lung dose, respectively.
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