Does adding chemotherapy to cytoreductive surgery improve the outcome of patients with peritoneal metastases from colorectal cancer?

This study evaluated the benefit of adding hyperthermic intraperitoneal chemotherapy (HIPEC) to cytoreductive surgery (CS) for the treatment of colorectal cancer (CRC) that has spread to the peritoneum (the lining of the abdomen that covers all abdominal organs). The study found that HIPEC added to CS did not improve the outcomes of these patients.

CRC is the third most common cancer worldwide. Many patients have CRC spread to other tissues or organs (metastasis). Metastatic CRC (mCRC) is more difficult to treat. CRC can spread to the peritoneum. Peritoneal mCRC (p-mCRC) is very difficult to treat and results in a worse outcome for patients.

Some patients with p-mCRC can undergo surgery to remove the tumor cells in the peritoneum. This is called CS. After the removal of peritoneal tumors, HIPEC is usually given. HIPEC involves delivering a solution of heated chemotherapy drugs into the abdomen during CS over 2 hours. This treatment aims to kill any remaining cancer cells left in the peritoneum with fewer side effects than systemic (whole-body) chemotherapy. However, it is unclear if HIPEC added to CS improves the outcomes of patients with p-mCRC. 

This study included 265 patients with p-mCRC. Group 1 included 132 patients randomly assigned to receive CS alone. Group 2 included 133 patients who had CS and HIPEC. The average follow-up time was 63.8 months.

The average overall survival was similar in group 1 (41.2 months) and group 2 (41.7 months). The average survival without relapse was also similar between groups 1 (11.1 months) and 2 (13.1 months).

After 1 month, 32% of patients in group 1 and 42% of patients in group 2 reported severe side effects. These included fistulas (an abnormal connection between the intestine and another abdominal organ) and abscesses (collection of puss).

The study concluded that adding HIPEC to CS for the treatment of p-mCRC did not improve patient outcomes.

Only patients who could have the entire tumor removed by surgery were included. Some patients randomly assigned to the CS alone group ended up having HIPEC because they had a relapse in peritoneal metastasis. This might have influenced the results.