Analysis of Intensity-Modulated Radiation Therapy (IMRT), Proton and 3D Conformal Radiotherapy (3D-CRT) for Reducing Perioperative Cardiopulmonary Complications in Esophageal Cancer Patients

Abstract

Background. While neoadjuvant concurrent chemoradiotherapy has improved outcomes for esophageal cancer patients, surgical complication rates remain high. The most frequent perioperative complications after trimodality therapy were cardiopulmonary in nature. The radiation modality utilized can be a strong mitigating factor of perioperative complications given the location of the esophagus and its proximity to the heart and lungs. The purpose of this study is to make a dosimetric comparison of Intensity-Modulated Radiation Therapy (IMRT), proton and 3D conformal radiotherapy (3D-CRT) with regard to reducing perioperative cardiopulmonary complications in esophageal cancer patients. Materials. Ten patients with esophageal cancer treated between 2010 and 2013 were evaluated in this study. All patients were simulated with contrast-enhanced CT imaging. Separate treatment plans using proton radiotherapy, IMRT, and 3D-CRT modalities were created for each patient. Dose-volume histograms were calculated and analyzed to compare plans between the three modalities. The organs at risk (OAR) being evaluated in this study are the heart, lungs, and spinal cord. To determine statistical significance, ANOVA and two-tailed paired t-tests were performed for all data parameters. Results. The proton plans showed decreased dose to various volumes of the heart and lungs in comparison to both the IMRT and 3D-CRT plans. There was no difference between the IMRT and 3D-CRT plans in dose delivered to the lung or heart. This finding was seen consistently across the parameters analyzed in this study. Conclusions. In patients receiving radiation therapy for esophageal cancer, proton plans are technically feasible while achieving adequate coverage with lower doses delivered to the lungs and cardiac structures. This may result in decreased cardiopulmonary toxicity and less morbidity to esophageal cancer patients.

Impact of Radiation on Cardiovascular Outcomes in Patients with Resectable Esophageal Cancer

“…Another key finding of this study relates to the observed reduction in postoperative cardiovascular events among patients receiving IMRT. Research evaluating radiation dosimetry demonstrates that the more conformal radiation dose distributions with IMRT have the potential to reduce radiation doses to the heart compared to conventional forms of radiation 14,[25][26][27][28] . Similarly, other retrospective analyses have found potential reductions in cardiovascular toxicity associated with IMRT compared to older radiation techniques 29,30 .…”

Esophageal cancer: comparative effectiveness of treatment options

“…The dosimetric advantages of proton therapy for esophageal cancer have been demonstrated in comparison to 3D-CRT and IMRT in several planning studies. [109][110][111] As compared to IMRT, both the two-beam and three-beam proton therapies resulted in much better lung sparing, with median lung V5, V10, V20, and MLD reduced by 35.6%, 20.5%, 5.8%, and 5.1 Gy and 17.4%, 8.4%, 5%, and 2.9 Gy, respectively. 110 In a dosimetric comparative study between IMRT and intensity-modulated proton therapy (IMPT), IMPT spared much more of the heart, lung, liver, and spinal cord.…”

“…112 In another comparative planning study, proton plans showed a decreased dose to various volumes of the heart and lungs, especially lung V5, while achieving adequate target coverage when compared to both the IMRT and 3D-CRT plans. 109 Furthermore, proton therapy can also improve heart sparing in terms of heart V30 and mean heart dose, which may reduce the risk of radiation-induced cardiovascular toxicity. Ling et al 109 reported that the proton plans delivered a significantly lower dose to the left anterior descending artery and left ventricle in comparison to both the IMRT and 3D-CRT plans.…”

“…109 Furthermore, proton therapy can also improve heart sparing in terms of heart V30 and mean heart dose, which may reduce the risk of radiation-induced cardiovascular toxicity. Ling et al 109 reported that the proton plans delivered a significantly lower dose to the left anterior descending artery and left ventricle in comparison to both the IMRT and 3D-CRT plans. Since irradiation of left anterior descending artery and left ventricle poses a particular risk to develop coronary artery and ischemic heart disease, 113 proton therapy may also reduce the risk of those diseases.…”

Variations in the Dose Profiles of Physical and Virtual Wedge Filters of ONCOR Linear Accelerator

“…To minimize potential radiation toxicity, small practical considerations such as how to use these wedge filters in treatment planning and modeling of these wedges in treatment planning beam profiles are very useful. The use of wedge filters in treatment of breast, thoracic, and pelvic tumors are very common and the steep dose gradient may produce hot spots in lungs, heart, and rectum in these cases [3][4][5][6].…”