Focused Radiation After Chemotherapy May Improve Mesothelioma Survival

New research suggests that mesothelioma patients who have focused radiation after chemotherapy may live longer with slower disease progression than those who have other therapy combinations.

Researchers used two kinds of focused radiotherapy (FRT) in the study. One was stereotactic body radiotherapy (SBRT) and the other was hypo-fractionated radiotherapy. Both treatments deliver a deadly dose of radiation into tumors while sparing normal tissue. 

Italian researchers say giving focused radiation after chemotherapy makes it even more effective against mesothelioma that is not yet widespread. 

Radiotherapy for Pleural Mesothelioma

Radiotherapy is one of several possible treatments for mesothelioma. Most patients start with chemotherapy. But chemotherapy has limited effectiveness. Increasingly, researchers are looking for other approaches to combat mesothelioma. 

Most patients get the best results from a combination of treatments. But there is no one-size-fits all approach. Pleural mesothelioma is resistant to many therapies, including radiotherapy. 

The new Italian study shows focused radiation after chemotherapy may work better. Chemotherapy may make mesothelioma cells more susceptible to radiation. The study suggests that the combination is a safe option for some cases of recurrent mesothelioma.

Testing Focused Radiation After Chemotherapy 

The new study included 37 patients with progressive mesothelioma. Patients had mesothelioma tumors in three or fewer sites besides the original tumor site. The name for this is “oligo-progressive”. Patients received treatment between 2006 and 2019. 

The patients had 43 mesothelioma lesions between them. They all had some chemotherapy first. Sixty percent of them had only had one course of chemotherapy. All patients had focused radiation after chemotherapy. 

Sixty percent of mesothelioma tumors received SBRT. SBRT is high dose radiation spread across many beams. The beams hit the tumor from different angles. It is a very precise form of radiotherapy. 

The other forty percent of mesothelioma tumors got hypofractionated radiotherapy. This approach also uses high doses of targeted radiation. Radiation is delivered in a short span of time. 

For patients who received focused radiation after just one course of chemotherapy, it took a median of 9 months for them to need more systemic therapy. Patients who needed more chemotherapy before FRT had to have systemic therapy again in about 4 months. 

At six months, local tumor control was 84 percent. That number dropped to 76 percent by one year. 

“FRT was feasible in selected patients with oligo-progressive MPM, allowing delay of further systemic therapies with no severe toxicity,” writes study author Paolo Ghirardelli of Cliniche Humanitas Gavazzeni in Bergamo. “FRT was more effective when performed at progression after one line of systemic therapy.”

Sources: 

Ghirardelli, P, et al, “Salvage radiotherapy for oligo-progressive malignant pleural mesothelioma”, November 30, 2020, Lung Cancer, Epub ahead of print, https://www.lungcancerjournal.info/article/S0169-5002(20)30698-X/fulltext?rss=yes#%20