Volume Modulated Arc Therapy (VMAT) for pulmonary Stereotactic Body Radiotherapy (SBRT) in patients with lesions in close approximation to the chest wall

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.Results: 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).Conclusions: 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.

Feasibility for Using Hypofractionated Stereotactic Volumetric Modulated Arc Radiotherapy (Vmat) With Adaptive Planning for Treatment of Thymoma in Rabbits: 15 Cases

“…The reported clinical signs on presentation including dyspnea, exopthalmos and anorexia are consistent with what has been previously reported in the literature . Reported suspected paraneoplastic syndromes in rabbits with thymoma include hemolytic anemia and dermatosis . Myasthenia gravis has not been reported in the rabbit.…”

“…These observations along with previous reports in the literature regarding other therapies for this disease indicate that VMAT is a feasible method for the treatment of thymoma in the rabbit. To our knowledge, the literature about radiation oncology has only a few reports focused on VMAT technology, applied to the chest and all studies had primary or metastatic lung pathology. Due to the frequent natural occurrence of thymoma in rabbits, this species can be studied in order to evaluate the radiobiological mechanism of the good response and minor radiotoxicity obtained with this treatment regimen.…”

Lung stereotactic ablative radiotherapy (SABR): dosimetric considerations for chest wall toxicity

“…The advent of volumetric modulated arc treatment for lung SABR has been shown to reduce chest wall doses, 27 and this may result in lower incidences of chest wall toxicity than have been observed with static beam arrangements. Furthermore, new parameters to limit chest wall toxicity may need to be defined, given the changes in dose distribution that occur with volumetric modulated arc treatment.…”

Predictors and management of chest wall toxicity after lung stereotactic body radiotherapy

“…Ding et al retrospectively evaluated ten patients treated with SBRT to a total dose of 60 Gy in 5 fractions [39]. When evaluating these treatment plans using Volume Modulated Arc Therapy (VMAT), the authors found a significant improvement in the V30 to the chest wall and ribs although there was an increase in the lung V20 of one patient.…”