Malignant peritoneal mesothelioma is cancer that develops in the abdominal cavity (peritoneal cavity), like polka dots on the lining of the intestines and the cavity. Peritoneal cases account for approx. 18%- 20% of all mesothelioma diagnoses,1 with approximately 400 new cases in the USA each year.2

Most patients (98%) were exposed to asbestos for an average of 28 years but the exposed time varied greatly (±14 years).2 Symptoms of peritoneal mesothelioma included abdominal pain and bloating, weight loss, shortness of breath, change to abnormal bowel movements (diarrhea or constipation), and chest pain. Median survival time ranged from 6 to 12 months2 and mean survival time was 16.2±13.9 months.3

Cytoreductive surgery for peritoneal mesothelioma reduces the tumor burden by removing the tumor nodules. Surgeons usually focus on removing tumor nodules of at least 1cm in size. The surgeon searches for nodules on the lining of the abdominal cavity, and the organs, including the 22 feet of small intestines and 4.9 feet of the large intestines. Hyperthermic intraperitoneal chemotherapy (HIPEC) is delivered afterwards. It means that the chemotherapy is delivered at a warm temperature (about 100°F) as it is more effective against the tumor cells.

Overall Survival Rate is Higher Than Average

The coupling of cytoreductive therapy and hyperthermic intraperitoneal chemotherapy boasts a 5 year overall survival rate of 29%-63% and a median overall survival of 77 months.2,4 The combined therapies are considered a potential cure for peritoneal mesothelioma.2

Some Patients Need a Second Round of Tumor Removal and Heated Chemotherapy

However, peritoneal mesothelioma recurs in some treated patients. About 21% of patients who initially received cytoreductive surgery and HIPEC received a second round of cytoreductive surgery. Most of the patients (64%) also received hyperthermic intraperitoneal chemotherapy.2 They received it on average within 12 months of the first treatment series.

Median Overall Survival Longer Than With Other Treatments

The median overall survival of patients who received the reiterative surgery and HIPEC was slightly shorter at 54 months.2

In comparison, patients who received cisplatin based chemotherapy for peritoneal mesothelioma had a median overall survival time of 15 months. Thus, the patients who can tolerate the cytoreductive therapy and heated chemotherapy usually live longer.

Survival rates at one year for pemetrexed treated group were 41.5% and the pemetrexed and cisplatin treated group was 57.4%.

Side Effects

Patients treated with reiterative cytoreduction therapy and warmed chemotherapy in Ihemelandu et al’s study had a 2% rate of severe illness that required surgical or radiological intervention with or without anesthesia (class III) or life-threatening complication such as CNS dysfunction, failure of one or more organs.2 In comparison, the same patients who received the first round of cytoreduction therapy had a 17% rate of severe illness.2

The authors did not describe the actual severe side effects.

In contrast, a different clinical study investigating reiterative cytoreduction for many types of peritoneal cancers had a severe side effect rate of 40%, which was greater than the 30% for the initial procedure.4 The benefits of the second cytoreduction depended on the type of cancer, the possibility of complete cytoreduction, younger age and better general health of patient, the scope and length of the first procedure, and the benefit of the first procedure (duration of no observable progression).

Do All Types of Peritoneal Mesothelioma Respond As Well?

No. According to the multi-institutional registry, the epithelioid cell type has the longest median survival of 63 months after cytoreduction therapy, and the multicystic histologic subtype shows a 54 month (or greater) median survival.5 In contrast, the mixed or sarcomatoid cell types showed a median survival of 16 months.5

Benefits vs. Risks

Thus, cytoreduction therapy provides greater survival benefits to patients with peritoneal mesothelioma of the epithelioid cell type than to patients with the mixed or sarcomatoid types. The cytoreduction surgeries have a risk of severe complications and so it is best to discuss the potential benefits compared to the risks with your team of physicians team who knows your health status.