European researchers reached that conclusion after the first Phase II randomized trial of postoperative hemithoracic (one-sided) radiotherapy in mesothelioma treatment.
Multimodal Mesothelioma Treatment
Because mesothelioma is both aggressive and highly resistant to conventional cancer therapies, most patients undergo several different types of treatment.
Radiotherapy can be used before mesothelioma surgery, after it, or instead of other treatments as a way to relieve symptoms.
In the case of the new study conducted at hospitals in Switzerland, Belgium and Germany, 113 enrolled mesothelioma patients first underwent chemotherapy to shrink their tumors, followed by extrapleural pneumonectomy (lung-removing mesothelioma surgery).
Mesothelioma patients who had good surgical results were then treated with high-dose radiotherapy to the affected side of their chest. The goal was to kill any remaining mesothelioma cells and prevent tumors from regrowing.
Radiotherapy Impact on Mesothelioma Survival
Of the 113 patients who underwent the lung-removing mesothelioma surgery, 96 achieved complete macroscopic resection or complete removal of the visible mesothelioma tumor. Fifty-four of these patients agreed to be assigned to a radiotherapy group or a non-radiotherapy control group for further treatment.
Twenty-five of the mesothelioma patients ended up receiving radiation treatment. Unfortunately, their rate of mesothelioma relapse was not significantly better than that of the non-radiotherapy group.
“Median locoregional relapse-free survival from surgery was 7.6 months in the no radiotherapy group and 9.4 months in the radiotherapy group,” reports lead researcher Rolf Stahel, MD, a molecular biologist in the University Hospital of Zurich. “Our findings do not support the routine use of hemithoracic radiotherapy for malignant pleural mesothelioma after neoadjuvant chemotherapy and extrapleural pneumonectomy.”
Complications of Radiotherapy After Mesothelioma Surgery
Not only did the post-surgical radiation treatment fail to extend mesothelioma survival, but it also caused some serious side effects in the study subjects.
Eleven percent of the patients who received radiotherapy for mesothelioma suffered from severe nausea or vomiting. Two (7%) suffered from an inflammation of the lining of the esophagus and two contracted pneumonitis, an inflammation of the walls of alveoli in the lungs.
One mesothelioma patient died from pneumonitis following the radiation treatment.
The new report is published in The Lancet, Oncology.
Stahel, RA, et al, “Neoadjuvant chemotherapy and extrapleural pneumonectomy of malignant pleural mesothelioma with or without hemithoracic radiotherapy (SAKK 17/04): a randomised, international, multicentre phase 2 trial”, October 30, 2015, The Lancet, Oncology, Epub ahead of print