That is the finding, and the question, raised by cancer researchers at Japan’s Kyoto University in a recent article published in the Swedish medical journal, Acta Oncologica.
In their study of 21 pleural mesothelioma patients, intensity modulated radiotherapy (IMRT) after EPP surgery produced an overall 3-year survival rate of 37.5% – more than double the typical pleural mesothelioma survival rate of 12 to 18 months.
IMRT in Pleural Mesothelioma Treatment
IMRT is a form of highly-targeted radiation therapy. By conforming to the shape of a mesothelioma tumor or to the margins of a tumor resection site, IMRT makes it possible to direct a high dose of radiation into cancer cells with less harm to healthy cells.
But, as the new study found, even IMRT cannot completely eliminate radiation-associated toxicities and side effects.
Side Effects of IMRT After EPP
Twenty-one mesothelioma patients were enrolled in the Japanese study. All of the patients had undergone the radical lung-removing mesothelioma surgery known as extrapleural pneumonectomy (EPP).
Although all 21 patients were supposed to receive a radiation dose of 50.4 Gy, four patients were unable to complete their course of treatment because of severe fatigue or radiation pneumonitis, a type of lung inflammation.
In all, fifteen mesothelioma patients developed acute treatment-related toxicities. In addition to pneumonitis, there were cases of serious nausea and vomiting, fatigue, and hematological problems.
Five patients developed serious radiation side-effects later including death of brain tissue (cerebral infarction), liver dysfunction, and serious deficiency of blood platelets called thrombocytopenia.
Good News for Mesothelioma Patients
Despite the side effects and complications, the study did produce some good news for people with malignant mesothelioma and their families. The median mesothelioma survival among study participants was 17.5 months after IMRT treatment and 27 months after their original surgery.
Only two patients experienced a regrowth of their tumors in the same spot after treatment, although 15 patients eventually developed metestatic mesothelioma tumors in other locations.
At the time of publication, three of the mesothelioma patients in the study had been alive for five years.
In his summary of the research, author Yukinori Matsuo reached an upbeat conclusion, but included a caveat:
“IMRT following EPP achieved excellent local control for MPM, that might lead to the long-term survival in selected patients,” writes Matsuo. “However, treatment burden including acute and late toxicities should be considered in this treatment approach.”
Matsuo, Y, “Long-term outcomes of intensity-modulated radiotherapy following extra-pleural pneumonectomy for malignant pleural mesothelioma”, January 24, 2017, Acta Oncologica, Epub ahead of print,