Prophylactic Radiotherapy for Pleural Mesothelioma: Is it Worth It?

Should mesothelioma patients consider having radiotherapy as a way to keep their symptoms from coming back after surgery? A new study suggests that the answer is probably “no”.

In an article published in the online medical journal PLoS One, researchers concluded that radiotherapy aimed at stopping the spread of pleural mesothelioma and delaying the return of symptoms may not not have much of an impact on quality of life for patients.

That recently-released finding comes from data collected during the Surgical and Large Bore Procedures in Malignant Pleural Mesothelioma and Radiotherapy (SMART) trial, a multicenter trial based in the UK.

Evaluating Radiotherapy for Mesothelioma

The purpose of the SMART trial was to evaluate the effectiveness of prophylactic radiotherapy started within 42 days of a “large bore” pleural mesothelioma procedure. (Examples of large bore procedures include thoracic surgery, a large bore chest drain, indwelling pleural catheters, or thoracoscopy.)

Any time an instrument is inserted into the tumor area and removed, there is the possibility of inadvertently “seeding” tiny new tumors along its tract. Because radiotherapy disturbs the DNA of cells along the insertion path, some studies have suggested that it may help keep pleural mesothelioma from gaining a foothold there.

The trial included 203 malignant pleural mesothelioma patients who had one of these large bore procedures and subsequently underwent either prophylactic radiotherapy (started before new tumors appeared) or deferred radiotherapy that was based on their symptoms.

Using quality of life data from the SMART patients, researchers from Dalhousie University and the University of Saskatchewan in Canada and the University of Bristol in the UK determined that the prophylactic radiotherapy did not improve patients’ lives enough to make it worth the cost.

Comparing Two Approaches to Mesothelioma Symptom Management

Mesothelioma patients in the SMART trial were asked to fill out quality of life questionnaires to determine how big an impact radiotherapy had. In addition, healthcare utilization and costs were also gathered during the trial.

Unfortunately for patients and their families, the researchers found very little difference between radiotherapy started early and radiotherapy administered in response to mesothelioma symptoms.

“There was no significant effect of prophylactic radiotherapy on quality of life in the intervention group, nor was there any discernible decrease in healthcare costs,” writes lead study author Samuel Alan Stewart of Dalhousie University. “There is little evidence to suggest that prophylactic radiotherapy is a cost-effective intervention in this population.”

Radiotherapy May Still Help Prevent Mesothelioma Spread

Although the SMART trial data suggests that prophylactic radiotherapy may not have much impact on quality of life for people diagnosed with mesothelioma, there is still evidence that it may help keep mesothelioma from spreading and extend survival.

An article published by French researchers late last year found that, a year after undergoing large-bore mesothelioma procedures, only 8 percent of 91 patients had experienced a recurrence of mesothelioma tumors at the intervention sites. In cases where tumors did form, it took a median of four months.

Just as importantly, there were no serious (Grade II or higher) side effects as a result of these prophylactic mesothelioma treatments.

Source:

Stewart, SA, et al, “Evaluating quality of life and cost implications of prophylactic radiotherapy in mesothelioma: Health economic analysis of the SMART trial”, February 2018, PLoS One, eCollection