Colorectal cancer at high risk of peritoneal metastases: long term outcomes of a pilot study on adjuvant laparoscopic HIPEC and future perspectives.

OBJECTIVE Early detection of peritoneal metastases (PM) of colorectal cancer (CRC) is difficult and treatment options at a clinically overt stage are limited. Potentially, adjuvant laparoscopic hyperthermic intraperitoneal chemotherapy (HIPEC) is of value. The aim of this study was to present long term oncological outcomes of a pilot study on adjuvant HIPEC to reduce development of PMCRC, with systematic review of literature. METHODS Long term oncological outcomes of ten patients who underwent laparoscopic HIPEC within eight weeks after resection of primary CRC in the pilot study were retrospectively collected. A systematic search of literature was performed on studies describing the use of HIPEC in patients with CRC at high risk of developing PM. RESULTS The median follow-up was 54 months (range 49-63). All patients were alive at the last follow-up moment and none of them had developed PM. Two patients had developed pulmonary metastases. Systematic review revealed five small cohort studies, including two matched comparisons. Peritoneal recurrences were found in 0% to 9% after adjuvant HIPEC, which was 28% and 43% in the two control groups, respectively. Disease free and overall survival were significantly higher in favour of HIPEC. CONCLUSION Long term follow-up of ten patients included in a pilot study on adjuvant HIPEC revealed no peritoneal recurrences. This result is in line with other published pilot studies, a promising observation. However, the outcomes of the Dutch randomized COLOPEC trial and similar trials worldwide should be awaited for definitive conclusions on the effectiveness of adjuvant HIPEC.