Peritoneal mesothelioma patients with high levels of a certain protein may not be good candidates for mesothelioma surgery.
Italian researchers came to that conclusion after evaluating the medical records of 117 patients with peritoneal mesothelioma. The patients had all undergone the gold standard mesothelioma treatment of cytoreductive surgery (CRS) followed by heated intraperitoneal chemotherapy (HIPEC).
Characteristics of Mesothelioma Surgery Candidates
Most of the mesothelioma patients included in the study (102) had the epithelioid type of peritoneal mesothelioma, a cancer that spreads across the lining of the abdomen. The rest had either sarcomatoid or biphasic mesothelioma.
More than 80 percent of the patients were “optimally cytoreduced”, meaning that their mesothelioma surgeries removed as much of the disease as possible.
All of the candidates for mesothelioma surgery were tested for the presence of Ki-67, a protein associated with cell proliferation.
Protein May Be Key to Survival After Mesothelioma Surgery
Of all the factors that influence outcomes in patients with peritoneal mesothelioma after surgery, the research team found just three that stood out as independent predictors of overall survival.
The first and most influential factor in determining candidates for mesothelioma surgery was the Ki-67 level, which ranged from 1 to 60 percent in the test subjects with a median of 5 percent.
Other factors that appeared to influence mesothelioma survival were histological subtype and peritoneal cancer index (PCI), a measure of how far mesothelioma had spread.
Best Candidates for Mesothelioma Surgery Had Low Scores
The study determined that patients who had levels of Ki-67 that were above 9 percent and PCI scores above 17 tended to have lower survival and were not good candidates for mesothelioma surgery.
Writing in the Annals of Surgical Oncology, lead researcher Shigeki Kusamura, MD, PhD, writes, “Ki-67 is a powerful prognosticator that allows, along with PCI, and histological subtype, a good prediction of overall survival in patients with diffuse malignant peritoneal mesothelioma.”
Peritoneal mesothelioma accounts for about 500 of the 2,500 cases of malignant mesothelioma in the United States each year.
Kusamura, S, et al, “The Role of Ki-67 and Pre-cytoreduction Parameters in Selecting Diffuse Malignant Peritoneal Mesothelioma (DMPM) Patients for Cytoreductive Surgery (CRS) and Hyperthermic Intraperitoneal Chemotherapy (HIPEC)”, November 16, 2015, Annals of Surgical Oncology, Epub ahead of print