Preoperative radiation improved survival in malignant pleural mesothelioma

Radiation prior to surgery more than doubled survival in patients with malignant pleural mesothelioma, according to results of a combined phase 1/phase 2 study.

The prospective single cohort clinical feasibility study evaluated the effectiveness of a method called Surgery for Mesothelioma After Radiation Therapy (SMART).

Researchers enrolled 25 patients with resectable, previously untreated malignant pleural mesothelioma. All patients underwent 5 days of intensity-modulated radiation therapy (IMRT) at Princess Margaret Cancer Centre, followed by extrapleural pneumonectomy surgery at Toronto General Hospital.

Treatment-related mortality served as the study’s primary endpoint. Secondary endpoints included OS, DFS, treatment-related morbidity and failure patterns.

“The 3-year survival rate more than doubled from 72% to 32%,” John Cho, MD, a radiation oncologist at Princess Margaret Cancer Centre and assistant professor in the department of radiation oncology at the University of Toronto, said in a press release. “The patients in our study experienced shorter treatment, fewer complications and speedier recovery.”

Aggregate 3-year survival rates were 84% in patients with epithelial histologic subtypes and 13% in biphasic subtypes (P=.0002).

Researchers found IMRT to be well tolerated. They observed no grade ≥3 toxicities.

Surgery was performed 62 days after completion of IMRT. No patients died during surgery.

Thirteen patients experienced grade ≥3 surgical complications, and one patient (4%) died of treatment-related toxicity during postoperative follow-up.

At last follow-up, only one of the nine patients with epithelial N2-negative disease had experienced a recurrence.

“These research results offer real hope to mesothelioma patients who have too often been told in the past that they may have only 6 months to live,” researcher Marc de Perrot, MD, a thoracic surgeon at University Health Network, University of Toronto, said in the press release. “We need to shorten the diagnostic and treatment cycle in mesothelioma because we now have an approach that makes it possible to control the disease and improve quality of life for several years.”

Disclosure: The study was supported by the Princess Margaret Hospital Foundation Mesothelioma Research Fund.