Peritoneal Mesothelioma and Multi-Modality Treatment

Combining surgery, localized chemotherapy and gamma-interferon-1b, and radiation can increase survival for patients with peritoneal mesothelioma, according to a recent study in the American Journal of Clinical Oncology.

Currently, no standard treatment exists for peritoneal mesothelioma, a rare cancer of the abdominal lining (peritoneum). Because the disease is typically confined to the abdomen, treatment usually consists of local therapies such as surgery or chemotherapy. In the current study, researchers investigated whether combining surgery with locally delivered chemotherapy, biological therapy (gamma-interferon-1b), and radiation might slow the progression of the disease and improve survival.

The study involved 27 patients (average age, 53) with malignant peritoneal mesothelioma. All of the participants underwent surgery in which doctors removed all traces of visible disease—a time-intensive procedure known as debulking.

“If you open the abdominal cavity, the cancer will form a pattern of salt-and-pepper sprinkled throughout the abdomen. It’s hard to take out because it doesn’t grow in discrete masses,” explains Mary Hesdorffer, MS, APRN, nurse practitioner with the Mesothelioma Applied Research Foundation, and medical liaison for the Mesothelioma Foundation. “Surgery is normally an eight or nine hour operation in which the surgeon painstakingly removes all of these little bits and pieces of disease to prepare for chemotherapy.”

After surgery, patients received chemotherapy and then biological therapy with gamma interferon-1b delivered directly into the peritoneal space. Then they had a second surgery to remove whatever cancer remained, followed by radiation to the abdomen and pelvis.

Patients who underwent this treatment lived for an average of nearly six years and had a three-year survival rate of 67%, a lifespan that is particularly significant considering that patients with the disease typically survive only six to nine months. Patients with epithelial form of the disease had the best odds of treatment success (a three-year survival rate of 78%), while those with the sarcomatoid form of the disease fared worst (all four patients in the study died within 11 months).

Seven patients in the study had no evidence of disease after more than seven years of follow-up—a promising outcome, although Hesdorffer is hesitant to label it a “cure.” “We can say that they’re in a substantial remission, but I don’t know if we can say cure yet because “cure” hasn’t yet been defined in this disease,” she says.

Still, the results suggest that the combination of surgery, chemotherapy, and radiation should be “considered the standard of care for patients with peritoneal mesothelioma,” says Hesdorffer. She says it’s important for doctors to be aware of the outcome of studies such as this one, because they are often reluctant to aggressively treat patients they believe to have a poor overall prognosis. “Most doctors tell them to go home and prepare to die.”

The best way to target this disease is to enroll patients in clinical trials at centers specializing in peritoneal mesothelioma, according to Hesdorffer.

Source: Hesdorffer ME, et al. Combined resection, intraperitoneal chemotherapy, and whole abdominal radiation for the treatment of malignant peritoneal mesothelioma. Am J Clin Oncol. 2008;31:49-54.