Cancer doctors at Mayo Clinic say they do not plan to start routinely performing radiotherapy before mesothelioma surgery.
The idea is based on a radiation protocol called SMART. The team monitored how well the SMART protocol worked among their pleural mesothelioma patients over a one year period.
The Mayo doctors acknowledged that radiotherapy before mesothelioma surgery can sometimes improve outcomes. But too many of their patients developed serious complications. In a recently-published article, the team concludes that SMART may not be worth the risk for most patients.
The SMART Way to Treat Mesothelioma?
Pleural mesothelioma grows on the membrane that surrounds the lungs. Mesothelioma tumors lie close to the lungs and heart and may spread to one or both lungs. Surgery to remove such a tumor is delicate and risky.
SMART stands for Surgery for Mesothelioma After Radiation Therapy. The idea is that radiotherapy before mesothelioma surgery may shrink the tumor and make it easier to remove.
Doctors have experimented with different ways of using SMART in mesothelioma treatment. One study found no quality of life benefit from prophylactic radiotherapy before a “large bore” procedure. (A large bore procedure is one where doctors need to make a hole in the chest.)
Another study of SMART in France used a faster kind of radiotherapy before mesothelioma surgery. These patients lived longer and had fewer side effects. An ongoing Canadian trial of SMART is testing the protocol in patients having lung-sparing P/D surgery.
A Real-World Test of Radiotherapy Before Mesothelioma Surgery
The Mayo Clinic test included five mesothelioma patients treated between 2016 and 2017. The patients had radiotherapy before mesothelioma surgery to remove the pleural membrane and one lung. This is extrapleural pneumonectomy (EPP) surgery.
The patients received their radiation with IMRT. Doctors delivered 30 Gy to their tumors and 25 Gy to the entire pleura. They underwent EPP 4 to 10 days later.
Some of the Mayo Clinic patients had problems after their SMART treatment. One developed both respiratory and kidney failure and had to go on dialysis. Another needed several more surgeries. Two patients developed atrial fibrillation. One had “acute respiratory distress” and needed a breathing tube.
But the results were not all bad. One patient who had radiotherapy before mesothelioma surgery lived for 1.4 years. (The average is about a year.) Two patients were still alive at follow-up but their malignant mesothelioma had come back. The remaining two were alive with no sign of mesothelioma at 0.1 and 2.7 years.
“SMART provided promising oncologic outcomes at the cost of significant treatment related morbidity,” the researchers conclude. “Due to the significant treatment-associated morbidity and favorable treatment alternatives, we have not broadly adopted SMART at our institution.”
Breen, WG, et al, “Surgery for Mesothelioma After Radiation Therapy (SMART); A Single Institution Experience”, March 24, 2020, Frontiers in Oncology, eCollection, https://www.frontiersin.org/articles/10.3389/fonc.2020.00392/full