Aggressive malignant peritoneal mesothelioma responds to treatment with Alimta (pemetrexed) and Platinol (cisplatin) chemotherapy, reports a study examining patient outcomes.
But more studies are needed to compare chemo’s effectiveness to surgery in this type of mesothelioma, which, according to researchers at Japan’s Hyogo College of Medicine, is a much more variable disease than its pleural counterpart.
The study, “First-line chemotherapy with pemetrexed plus cisplatin for malignant peritoneal mesothelioma,” appeared in the journal Expert Review of Anticancer Therapy.
Chemotherapy with Alimta and Platinol is a standard treatment in patients with pleural mesothelioma. But since peritoneal disease is much rarer, the approach has never been evaluated in a clinical trial setting. The treatment’s use t in peritoneal mesothelioma is, instead, based on results from pleural mesothelioma trials.
But the Japanese team underscored that pleural and peritoneal disease differ in their causes and disease mechanisms. For instance, only about one-third of patients with peritoneal mesothelioma have been exposed to asbestos.
In order to evaluate potential benefits of chemotherapy as a first-line treatment, the team retrospectively analyzed the medical records of 24 patients.
None of the 16 men and eight women in the group had metastatic disease. Twenty-two of the 24 had epithelioid tumors, while seven each had wet or dry-painful type mesothelioma, and 10 had a combined disease type.
Dry-painful type is characterized by abdominal pain and multiple masses, with little or no fluid buildup in the abdomen. Wet type is characterized by large malignant fluid buildup without abdominal pain, and combined type has the characteristics of both the dry-painful and wet types.
Two of the 24 patients achieved a complete response to chemo. Another nine had partial responses and 11 had stable disease. This translates to an objective response rate of 45.8 percent and a disease control rate of 91.7 percent.
Patients had a median progression-free survival of 11 months and overall survival of 15.8 months. While the one-year survival rate was 58.3 percent, it dropped to 20.8 percent in the second year and 12.5 percent at year three.
But patients who had wet-type disease had much better survival times than other patients, the team noted. Wet-type patients lived for a median of 40.9 months, while those with dry-painful disease had an overall survival of 21.5 months. Patients with combined type disease had the shortest survival time, 9.6 months.
Although small, the team argued that the study provided proof that first-line chemotherapy is effective in peritoneal mesothelioma. But, they said, doctors should evaluate whether surgery, combined with intraperitoneal chemotherapy, might be an even better option for some patients.