SAN DIEGO – National guidelines for the treatment of malignant pleural mesothelioma often are not followed, a new study showed, with fewer than one-third of patients receiving cancer-directed surgery.
Another 32% received no treatment, although that didn’t seem to have an impact on median months of survival.
Dr. Harmik Soukiasian
Still, “there can be a wide variation in median survival time, depending on clinical factors and tumor characteristics,” said study coauthor Harmik Soukiasian, MD, of Cedars-Sinai Medical Center, Los Angeles. “Given the variation in prognosis, it is quite astonishing that over 30% of MPM patients are not receiving any form of treatment. As clinicians armed with these data, we need to investigate why that is.”
Dr. Soukiasian presented the study findings at the annual meeting of the American Association for Thoracic Surgery.
MPM, a rare cancer, is mainly linked to asbestos exposure. “MPM is almost always a fatal disease, and the prognosis can only be modestly influenced by oncological treatments,” according to the authors of guidelines released in 2013. “The diagnostic process can be complex, with highly specialized advice frequently required to arrive at a definite diagnosis. Treatment varies from therapeutic nihilism to radical combined-modality treatment approaches” (J Thorac Dis. 2013 Dec;5[6]:E254-E307).
Surgical resection is a controversial treatment for MPM, Dr. Soukiasian said. It is “based on the principle of macroscopic resection of solid tumor with adjuvant therapy to treat micrometastatic disease,” he explained. “Cancer-directed surgery for MPM is usually reserved for localized epithelial type histology and is associated with a 5-year survival rate of 15%.”
For the new study, the investigators tracked 3,834 patients in the National Cancer Database (2004-2014) diagnosed with MPM clinical stages I-III. Most had epithelioid MPM (69%), with sarcomatoid (17%) and mixed subtype (15%) making up the rest. They examined whether patient treatment complied with the National Comprehensive Cancer Network (NCCN) guidelines, which recommend surgery in resectable epithelioid MPM.