Intensity-Modulated Radiation Therapy Improves the Target Coverage Over 3-D Planning While Meeting Lung Tolerance Doses for All Patients With Malignant Pleural Mesothelioma

Abstract

Purpose: To investigate high conformality on target coverage and the ability on creating strict lung dose limitation of intensitymodulated radiation therapy in malignant pleural mesothelioma. Patients and Methods: Twenty-four radiation therapy plannings were evaluated and compared with dosimetric outcomes of conformal radiation therapy and intensity-modulated radiation therapy. Hemithoracal radiation therapy was performed on 12 patients with a fraction of 1.8 Gy to a total dose of 50.4 Gy. All organs at risk were contoured. Radiotherapy plannings were differed according to the technique; conformal radiation therapy was planned with conventionally combined photon-electron fields, and intensity-modulated radiation therapy was planned with 7 to 9 radiation beam angles optimized in inverse planning. Strict dose-volume constraints were applied. Results: Intensity-modulated radiation therapy was statistically superior in target coverage and dose homogeneity (intensity-modulated radiation therapyplanning target volume 95 mean 100%; 3-dimensional conformal radiation therapy-planning target volume 95 mean 71.29%, P ¼ .0001; intensity-modulated radiation therapy-planning target volume 105 mean 11.14%; 3-dimensional conformal radiation therapy-planning target volume 105 mean 35.69%, P ¼ .001). The dosimetric results of the remaining lung was below the limitations on intensity-modulated radiation therapy planning data (intensity-modulated radiation therapy-lung mean dose mean 7.5 [range: 5.6%-8.5%]; intensity-modulated radiation therapy-lung V5 mean 55.55% [range: 47%-59.9%]; intensity-modulated radiation therapy-lung V20 mean 4.5% [range: 0.5%-9.5%]; intensity-modulated radiation therapy-lung V13 mean 13.43% [range: 4.2%-22.9%]). Conclusion: With a complex and large target volume of malignant pleural mesothelioma, intensitymodulated radiation therapy has the ability to deliver efficient tumoricidal radiation dose within the safe dose limits of the remaining lung tissue.

Therapeutic efficacy evaluation of radioimmunotherapy with 90Y‐labeled anti‐podoplanin antibody NZ‐12 for mesothelioma

“…Most mesothelioma cells spread into the diaphragm, chest wall, and mediastinum with an irregular shape and are close to critical structures such as the spinal cord, liver, esophagus, heart, and lungs . Therefore, external‐beam radiation to mesothelioma in the thorax and mediastinum has substantial technical limitations . The most common toxicities in patients treated with external‐beam radiation for thoracic cancer are symptomatic radiation pneumonitis, and the mean dose to the lungs for 20% risk of radiation pneumonitis is 20 Gy .…”

“…42 Therefore, external-beam radiation to mesothelioma in the thorax and mediastinum has substantial technical limitations. 42,43 The most common toxicities in patients treated with external-beam radiation for thoracic cancer are symptomatic radiation pneumonitis, 44 and the mean dose to the lungs for 20%…”

Dosimetric Correlates of Pulmonary Toxicity in Patients with Malignant Pleural Mesothelioma Receiving Radiation Therapy to the Intact Lungs

“…17 Others have recommended limiting contralateral lung V20 < 4-10% following EPP. 14,18 In the current study, all patients received pleurectomy/ decortication and planning protocols dictated limiting the contralateral lung as much as possible. It is possible that a correlation between RP and contralateral lung dose was not seen because the dose to the contralateral lung in all patients was too low to see a difference.…”

Safety and Efficacy of the Metabolic Profiling of the BIMRT Utilizing 18F FDG PET-CT

“…But, BIMRT has provided a new treatment method for some of these patients, possibly with better results and relatively higher quality of life. 22…”