Advanced new radiotherapy techniques may be more effective – and less toxic – for hard-to-treat mesothelioma patients.
Caused by exposure to asbestos, malignant pleural mesothelioma is a fast-growing cancer that spreads across the membrane that encases the lungs. Radiotherapy is often used as part of a multi-modality approach to keep mesothelioma from spreading. But because of the size and irregular shape of mesothelioma tumors, as well as their proximity to the lungs and heart, there is a high risk of damaging vital organs with conventional external beam radiotherapy.
Now, a study out of Australia demonstrates that new, more precise methods of radiotherapy delivery may be the best hope of controlling the growth of mesothelioma tumors. A team of radiologists at the University of Melbourne examined the outcomes of 14 mesothelioma patients who were treated with either high-dose three dimensional conformal radiotherapy (3DCRT) or intensity-modulated radiotherapy (IMRT) following surgery. Both technologies are designed to deliver higher doses of radiation into mesothelioma cells by customizing the shape of the beam. All of the patients in the study had treatment planning and post-treatment analysis using FDG-PET/CT scans.
Although four of the 14 patients did show signs of mesothelioma recurrence at the irradiated site, the remaining ten did not, an in-field local control rate of 71%. In addition, there were no serious treatment-related toxicities with either of the two types of high-dose rate radiotherapy methods. Median survival was 25 months from diagnosis and 17 months after starting radiotherapy.
Half of the patients did have metastases to other spots after their radiotherapy, but, for two patients, the radiotherapy appears to have stopped the mesothelioma in its tracks; as of the writing of the study, these patients had no further tumor growth and no metastases.
Reporting in the Australian Medical Journal, Journal of Medical Imaging and Radiation Oncology, the authors concluded, “Radiotherapy should be considered to prevent or delay the local manifestations of progressive disease in suitable patients after surgery including extrapleural pneumonectomy and pleurectomy/decortication.” They go on to suggest that higher doses of radiation may result in even more effective palliation of mesothelioma symptoms.
Feigen, M et al, “establish locoregional control of malignant pleural mesothelioma using high-dose radiotheraoy and (18) F-FDG-PET/CT scan correlation”, June 2011, pp. 320-32.