Effect of Increasing Experience on Dosimetric and Clinical Outcomes in the Management of Malignant Pleural Mesothelioma With Intensity-Modulated Radiation Therapy

• Published in: International journal of radiation oncology, biology, physics Vol. 83; no. 1; pp. 362 - 368
• Main Authors: Patel, Pretesh R., M.D, Yoo, Sua, Ph.D, Broadwater, Gloria, M.S, Marks, Lawrence B., M.D, Miles, Edward F., M.D, D’Amico, Thomas A., M.D, Harpole, David, M.D, Kelsey, Chris R., M.D
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.05.2012; Elsevier
• Subjects: Aged; Antineoplastic Combined Chemotherapy Protocols - therapeutic use; Applied radiobiology (equipment, dosimetry...); Biological and medical sciences; Biological effects of radiation; Cancer Care Facilities; CHEMOTHERAPY; CHEST; Clinical Competence; Female; Fundamental and applied biological sciences. Psychology; GY RANGE 10-100; Hematology, Oncology and Palliative Medicine; Humans; IRRADIATION; Lung - radiation effects; LUNGS; Male; Medical sciences; Mesothelioma - drug therapy; Mesothelioma - mortality; Mesothelioma - radiotherapy; Mesothelioma - surgery; Middle Aged; NEOPLASMS; North Carolina; PATIENTS; PLANNING; Pleural Neoplasms - drug therapy; Pleural Neoplasms - mortality; Pleural Neoplasms - radiotherapy; Pleural Neoplasms - surgery; Pneumology; Pneumonectomy - methods; RADIATION DOSES; Radiation Injuries - prevention & control; Radiology; RADIOLOGY AND NUCLEAR MEDICINE; RADIOTHERAPY; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted - methods; Radiotherapy Planning, Computer-Assisted - standards; Radiotherapy, Intensity-Modulated - adverse effects; Radiotherapy, Intensity-Modulated - methods; Radiotherapy, Intensity-Modulated - standards; Regression Analysis; Retrospective Studies; SURGERY; Survival Analysis; Survival Rate; Tissues, organs and organisms biophysics; TOXICITY; Tumors of the respiratory system and mediastinum; North Carolina; Intensity modulated radiotherapy; Cancerology; Clinical management; Prognosis; Treatment; Respiratory disease; Pleural disease; Malignant tumor; Dosimetry; Malignant pleural mesothelioma; Cancer
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/j.ijrobp.2011.11.057

Purpose To assess the impact of increasing experience with intensity-modulated radiation therapy (IMRT) after extrapleural pneumonectomy (EPP) for malignant pleural mesothelioma (MPM). Methods and Materials The records of all patients who received IMRT following EPP at Duke University Medical Center between 2005 and 2010 were reviewed. Target volumes included the preoperative extent of the pleural space, chest wall incisions, involved nodal stations, and a boost to close/positive surgical margins if applicable. Patients were typically treated with 9-11 beams with gantry angles, collimator rotations, and beam apertures manually fixed to avoid the contalateral lung and to optimize target coverage. Toxicity was graded retrospectively using National Cancer Institute common toxicity criteria version 4.0. Target coverage and contralateral lung irradiation were evaluated over time by using linear regression. Local control, disease-free survival, and overall survival rates were estimated using the Kaplan-Meier method. Results Thirty patients received IMRT following EPP; 21 patients also received systemic chemotherapy. Median follow-up was 15 months. The median dose prescribed to the entire ipsilateral hemithorax was 45 Gy (range, 40-50.4 Gy) with a boost of 8-25 Gy in 9 patients. Median survival was 23.2 months. Two-year local control, disease-free survival, and overall survival rates were 47%, 34%, and 50%, respectively. Increasing experience planning MPM cases was associated with improved coverage of planning target volumes ( P =.04). Similarly, mean lung dose ( P <.01) and lung V5 (volume receiving 5 Gy or more; P <.01) values decreased with increasing experience. Lung toxicity developed after IMRT in 4 (13%) patients at a median of 2.2 months after RT (three grade 3-4 and one grade 5). Lung toxicity developed in 4 of the initial 15 patients vs none of the last 15 patients treated. Conclusions With increasing experience, target volume coverage improved and dose to the contralateral lung decreased. Rates of pulmonary toxicity were relatively low. However, both local and distant control rates remained suboptimal.