Mesothelioma Not Stopped By Radiation Therapy

You’re unlikely to live longer by including radiation therapy in your fight against mesothelioma, a University Hospital Zurich study asserts.

The study, presented at the European Society for Medical Oncology congress in Madrid, suggests that your best bets are mesothelioma surgery plus chemotherapy.

Current ESMO president and the study’s lead author Rolf A. Stahel, M.D., said high-dose radiation therapy adds no survival benefit after mesothelioma chemotherapy and radical surgery.

This was a Phase 2 study, Stahel indicated. He and his colleagues expressed disappointment in the findings because they started out hoping the opposite would prove true.

He told the healthcare news website that the research team’s aim was to see if radiation therapy could prevent relapse or at least delay it.

He said they would have considered it a success had the radiation therapy patients they monitored remained locally free of the disease for at least six months following treatment.

But mesothelioma returned quickly, he said.

Investigating Mesothelioma Survival Following EPP

Specifically, the researchers were investigating radiation therapy as an adjunctive treatment to extrapleural pneumonectomy.

EPP, as it’s also known, is a very tricky procedure which can only be performed on mesothelioma patients who have one disease-free lung.

In an EPP, the surgeons open your chest and carefully remove the diseased lung plus its lining and your diaphragm. This is followed by chemotherapy to knock out any mesothelioma cells missed by the knife.

A number of mesothelioma specialists who offer EPP also like to add radiation therapy to eliminate mesothelioma cells that might have resisted the chemotherapy.

The University Hospital Zurich researchers wanted to demonstrate that radiation therapy contributed value to the treatment combo.

Don’t Count Out Radiation as a Mesothelioma Strategy

The Phase 2 study involved a total of 153 patients slated to receive an EPP.

Prior to that surgery, each patient received chemotherapy in the form of cisplatin combined with pemetrexed. The chemotherapy was administered in three courses.

After the surgery, 54 patients were culled from the cohort. These were given either radiation therapy or nothing at all.

But here’s the interesting thing. Radiation therapy recipients actually went about 6 weeks longer being locally free of mesothelioma than did the chemotherapy and surgery group.

The researchers interpreted this as evidence that radiation therapy is not beneficial as an EPP adjunctive treatment because the extra days of survival were no big deal, nothing to write home about.

Even so, radiation therapy should not be counted out just yet.

Medscape interviewed Paul Baas, M.D., from the Netherlands Cancer Institute in Amsterdam, who said the researchers might get more encouraging results the next time they look at radiation therapy.

Selecting patients with different pathologies, different staging, and different performances could all influence the outcome, Medscape quoted Baas as saying.

Baas, by the way, is a big fan of molecularly targeted mesothelioma therapies. He believes there is a particular need to investigate use of immune checkpoint inhibitors that target the PD-1/PD-L1 (programmed death/programmed death-ligand 1) pathway.

According to Medscape, approximately 20 percent of malignant pleural mesothelioma patients have cancer cells that express PD-L1. PD-L1 has a reputation for deeply cutting into mesothelioma survival.