Comparison of two treatments for colorectal cancer that has spread to the peritoneum

This study compared two treatments for peritoneal metastasis in colorectal cancer (cancer that has spread to the lining of the abdomen). 

Peritoneal metastasis is a serious complication of colorectal cancer. It is not usually treatable with standard chemotherapy, which is injected into veins or given by mouth. Peritoneal metastases can also be treated with cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy (CS/HIPEC). In CS/HIPEC, the affected parts of the peritoneum are first surgically removed. The abdomen is then bathed with heated chemotherapy. The benefits and risks of CS/HIPEC compared to standard chemotherapy are not clear. 

This study examined the results of four other studies that compared standard chemotherapy with CS/HIPEC. The studies included 342 colorectal cancer patients with peritoneal metastases. 187 patients underwent CS/HIPEC and 155 received standard chemotherapy. Patient survival rates were examined for 5 years after treatment. Two studies also examined complication rates.

After 2 years, up to 65% of patients were still alive after standard chemotherapy and up to 81% were still alive following CS/HIPEC. After 5 years, up to 13% of patients were still alive after standard chemotherapy and up to 51% were still alive after CS/HIPEC. The odds of 2-year survival were 2.78 times higher, and the odds of 5-year survival were 4.07 times higher following CS/HIPIC than standard chemotherapy.

Two studies reported complications following CS/HIPIC. Out of 18 patients in one study, 22% experienced severe pain, 11% experienced nausea and vomiting, and 27.5% experienced bowel blockage. In a second study of 54 patients, two (4%) developed severe blood infections (sepsis). Other severe complications included low numbers of white blood cells (cells needed to fight infections; 15%), heart failure (8%), bleeding (6%), and kidney failure (6%).

The authors concluded that for certain patients, CS/HIPEC improves survival compared to standard chemotherapy.