Radiotherapy No Longer Routine for Mesothelioma Patients
Prophylactic radiotherapy — once offered routinely after invasive procedures for pleural mesothelioma — is an unnecessary treatment for patients, according to the most recent study from the United Kingdom.
Results from a large, multicenter clinical trial have shown the treatment — used regularly for almost two decades — does little to prevent chest-wall metastasis that can occur with mesothelioma cancer.
“This should be helpful for patients to know if their oncologist is offering something they don’t really need,” clinical oncologist Dr. Neil Bayman, associate medical director at the Christie NHS Foundation Trust in Manchester, England, told The Mesothelioma Center at Asbestos.com. “For most, there is no benefit.”
The Journal of Clinical Oncology published the study results in June 2019.
Conflicting Evidence in the Past
The study involved 375 pleural mesothelioma patients from 54 hospitals who had undergone a chest wall procedure. Those include open-surgical biopsy, video-assisted thoracoscopic surgery, local anesthetic thoracoscopy or chest-drain insertion.
Previous studies have shown those procedures can cause tumor-cell seeding at the site and chest wall metastasis in anywhere from two to 50% of patients.
The prevailing belief, since the mid-90s, was prophylactic radiotherapy to the site of the chest wall could help prevent that problem.
“We’ve always worried that we were sending patients back and forth for treatment they didn’t really need. And that all it did was delay the chemotherapy,” Bayman said. “We wanted a large study to answer the question once and for all.”
In the randomized trial, researchers found little significant difference between those who underwent prophylactic radiation and those who did not.
At six months, six of 186 patients who received treatment had chest wall metastasis, compared with 10 of 189 patients who did not receive treatment.
At one year, the numbers increased to 15 and 19 patients, respectively.
At two years, there were 17 patients in the treatment group with chest wall metastasis and 29 in the nontreatment group.
Because the overall survival rate was less than 25% at 24 months, the difference was not considered significant to the study.
“We’ve gone from saying everyone should have it, to now saying it’s not effective,” Bayman said. “There still may be a group in the middle for whom it can be helpful, though. Instead of a one-size-fits-all standard — which it has been historically — we should try and personalize it.”
Even before the study was published, the routine use of prophylactic radiation had dropped significantly in the United States, although it still is being used in certain cases.
Improved Chemotherapy Taking Its Place
The National Comprehensive Cancer Network, a group of more than 30 leading centers in the U.S., recently changed its treatment guidelines to advise against routine prophylactic radiation.
“The study affirms the recent practice pattern,” radiation oncologist Dr. Charles Simone, chief medical officer at the New York Proton Center, told The Mesothelioma Center at Asbestos.com. “This is an important study for patients to be aware of, to help make informed decisions if they are offered this procedure. In recent years, it’s been more common in Europe than in the U.S.”
Both Simone and Bayman believe the improvements in chemotherapy effectiveness in the last decade have decreased the incidence of, or at least delayed, the chest wall tumor seeding that was once more prevalent, lessening the need for the treatment.
Ending the routine use of the procedure will end the adverse side effects that sometimes come with radiation therapy and allow patients to begin chemotherapy sooner.
More than half of those in the study had Grade 1 radiation dermatitis and 10.2% reported Grade 2.
“Through the years, there had been conflicting signals about the benefit of the procedure,” Bayman said. “Not anymore.”
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1 Cited Article Sources
- Bayman, N. et. al. (2019, June 12). Prophylactic Irradiation of Tracts in Patients With Malignant Pleural Mesothelioma: An Open-Label, Multicenter, Phase III Randomized Trial. Retrieved from: https://ascopubs.org/doi/full/10.1200/JCO.18.01678