Accelerated high-dose radiation just before extrapleural pneumonectomy (EPP) surgery, a reversal of the traditional order at most U.S. specialty centers, continues to produce impressive results for pleural mesothelioma patients in Toronto.
Specialists at the Princess Margaret Cancer Centre and Toronto General Hospital estimated the median overall survival and disease-free survival at 51 and 47 months, respectively, for patients with the most common subtype of the disease.
Surgeon Marc de Perrot presented the findings of an ongoing study earlier this year at the American Association for Thoracic Surgery in Seattle.
His report also included a three-year survival rate of 66 percent among patients with the epithelial subtype and no lymph node involvement. That’s double the normal rate for a trimodality approach to treatment.
For those with lymph node involvement, there was a three-year survival of 48 percent.
Toronto Is Leading the Charge
The cancer center in Toronto is the first in the world to study a large number of patients using the Surgery for Mesothelioma After Radiation Therapy (SMART) approach to treatment. The Swedish Cancer Institute in Seattle is the only U.S. center using the protocol and reported impressive results in a much smaller sample.
Toronto’s study evaluated 62 patients from November 2008 to October 2014. All received a five-day dose of Intensity Modulated Radiation Therapy (IMRT) followed with the aggressive EPP surgery. Less than half of patients received adjuvant chemotherapy after surgery.
The more accepted multimodal treatment begins with chemotherapy, then surgery and concludes with radiation if it’s needed.
“When you have a very, very aggressive tumor, you need management that will match it aggressively,” Toronto radiologist John Cho, who co-authored the study, told Asbestos.com. “That’s what we do. This is not a fluke. We believe this approach is making a difference. We’ve been doing it a lot now, and it works.”
Patients in the study generally experienced a quicker recovery, a shorter treatment period and fewer complications, which has been encouraging for future surgical candidates.
“There is some skepticism out there, and I understand it,” Cho said. “It takes a tremendous amount of coordination to do this, and there are a lot of subtleties involved. But I’m convinced this is the way to go. If it were my parent, or my brother, as the patient, this is the treatment I would offer them.”
Toxic Level of Radiation
The reason for the skepticism or argument against this procedure is that Cho is delivering a toxic level of radiation to the lung, which could be fatal if it’s not subsequently removed during the surgery.
According to previous studies, only 80-85 percent of the patients who begin an EPP surgery procedure actually have a lung completely resected. Despite the best scans and diagnostic tools, a surgeon occasionally opens the chest and finds the cancer already has metastasized, and taking the diseased lung serves no purpose.
Radiation before the EPP eliminates the option of leaving the lung, which tightens the surgical selection process. There is no turning back once the procedure has begun.
During the time frame used in the study, there were 256 patients treated for malignant pleural mesothelioma at the Princess Margaret Cancer Center, but only 62 (24 percent) were deemed candidates for the procedure.
“This is not a cut-and-paste process that would transfer easily to other centers,” Cho said. “You need a surgeon and radiologist working closely together. You don’t ever want to be in a situation where you’ve painted yourself into a corner, then have someone change his mind.”
Prevents Mesothelioma Recurrence
The theory behind the radiation-first procedure, and why Cho and de Perrot believe this is optimal, is that it eliminates or decreases the cancer’s ability to seed or spill in the chest during the surgery.
Radiation reduces recurrence of the mesothelioma in other parts of the chest cavity by sterilizing the edges of the tumor bed. It also potentially activates a patient’s immune system.
EPP surgery is the most aggressive procedure done for pleural mesothelioma. It includes the removal of a lung, the lining around it, the pericardium and parts of the diaphragm.
It must be done within two weeks of the fifth and final day of radiation.
The procedure did not work well for 18 patients (29 percent) with the biphasic subtype of mesothelioma. They had a median disease-free survival of just eight months. The cancer center no longer offers the procedure for biphasic patients.
One of the 62 surgical patients died in the hospital just two months after surgery.
“The results have been encouraging,” the authors wrote. “They should support further studies.”