Cancer in the peritoneum is known as peritoneal carcinomatosis, which is a general term for spreading of tumor cells in the peritoneum often originating from other organs in the abdominal cavity. Spread may also occur when a tumor grows through an organ reaching the surface of the peritoneum. Free cancer cells can attach to different areas of the peritoneum.
The peritoneum is a thin membrane consisting of two layers:
- a peritoneal layer which lines the abdominal cavity
- a visceral layer which wraps around the internal organs in the intraperitoneal cavity
The narrow space between these two layers is filled with a thin fluid keeping the peritoneum moist to allow the two layers to glide freely. Double layer of peritoneum is known as mesentery which houses organs.
The most common point of origin for peritoneal cancer is the colon for both males and females, as well as the gynecologic organs in women. However, any tumors in the abdominal cavity can cause peritoneal carcinomatosis. Pseudomyxoma peritonei (PMP) is a malignant condition in the appendix characterized by mucinous ascites and peritoneal mucinous implantations. Mesothelioma is tumor originating from mesothelial cells, which create the protective lining covering the abdominal cavity. The most common origin is the pleural cavity, but tumor may also originate from the peritoneal cavity.
At Oslo University Hospital (Radiumhospital), maximal cytoreductive surgery (CRS) has been performed for peritoneal carcinomatosis since 1993. Since 2003, hyperthermic intraperitoneal chemotherapy (HIPEC) has also been performed. Oslo University Hospital is currently responsible for this combination treatment in Norway. CRS-HIPEC is rapidly growing in use in western countries, and gives patients with confined tumor spreading in the peritoneum a possibility for curative treatment (19).
Historically, this group of patients has previously been treated with systemic chemotherapy, palliative surgery, and/or abdominal radiation therapy giving poor results.
About 10% of patients with primary colon and rectal cancer have carcinomatosis at the time of diagnosis, 25% have carcinomatosis at the time of recurrence.
There are about 10 new cases of pseudomyxoma peritonei per year in Norway. Diffuse malignant peritoneal mesothelioma makes up 1/4 of all mesothelioma. About 1 patient/million/year is suitable for treatment.
In 2010, CRS was carried out on 60 patients at the Radiumhospital. Thirty-seven of these were also given HIPEC. It is reasonable to assume that nearly 80 patients per year are offered CRS-PEC in Norway.