Obesity Increases the Risk of Chest Wall Pain From Thoracic Stereotactic Body Radiation Therapy
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.
Available from: Aruna Turaka
- "If contour was outside of patient, it was brought into the external skin edge. Effort was made to include the thoracic nerve roots Dunlap  CW 3 cm expansion of lung minus lung volume, mediastinal soft tissue, vertebral body Kim  CW Ipsilateral hemibody that excluded the lungs and mediastinum Nambu  Ribs Contoured fractured ribs Stephans  CW Arc of all ipsilateral soft tissue outside of lung from edge of sternum circumferentially to the edge of the vertebral body including the spinal nerve root exit Taremi  Ribs Contoured ribs from the costovertebral to the costosternal/costal cartilage Welsh  CW Outer edge of patient's skin/chest wall automatically contoured minus total lung contour Bongers  CW Expansion of the lungs 2 cm in lateral, posterior, and anterior directions except in the direction of the mediastinum with inclusion of intercostal muscles but excluding other muscles and skin Woody  CW Contoured by expanding ipsilateral lung at least 3 cm in anterior, posterior, medial, lateral directions to cover relevant ribs and soft tissues and then adjusted to exclude spine, mediastinum, contralateral chest wall Mutter  CW 3 cm expansion of lung minus lung volume, mediastinal soft tissue, vertebral body Pettersson  Ribs Individual ribs receiving total dose of 21 Gy RTOG 1021/0915 Ribs Ribs within 5 cm of the PTV should be contoured by outlining the bone and marrow. Typically, several portions of adjacent ribs will be contoured as one structure. "
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ABSTRACT: Stereotactic body radiotherapy is the preferred treatment modality for patients with inoperable early stage lung cancer. Chest wall toxicity is a potentially dose limiting side effect and may include fractures or pain secondary to treatment. The pathophysiology of these symptoms is unclear although it is presumed that radiation may alter the bone’s normal tissue environment, affecting maintenance and remodeling. Chest wall pain is likely neuropathic secondary to injury to the intercostal nerves. Identifying patients with chest wall toxicity can be difficult due to the varying definitions of toxicity as well as heterogeneous contouring guidelines. Multiple studies have demonstrated a correlation between treatment factors and the incidence of chest wall toxicity. An increase in dose and treatment volume appear to be the most consistent radiation factors associated with toxicity. Patient factors such as body mass index, female gender, tumor location, and age have also been correlated with an increased likelihood of developing side effects. Management of chest wall toxicity is typically conservative using analgesic medications although surgical intervention may be required for displaced fractures. In this review, we examine the treatment, patient, and tumor factors predictive for chest wall toxicity and the implications for the treating physician.
Available from: Richard Moser
- "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). "
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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.
Available from: Berend J Slotman
- "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 . "
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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.
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