CRC with peritoneal metastases: CRS-HIPEC refinements

Results of several new studies provide important perspectives on the use of hyperthermic intraperitoneal chemotherapy (HIPEC), a specialized treatment for cancers that have spread to the inner lining of the abdomen (peritoneal metastases). HIPEC is typically used in combination with cytoreductive surgery (CRS), an approach that aims to reduce the number of cancer cells through surgical removal of tumours.

About 5% of patients with colorectal cancer (CRC) have peritoneal metastases. While HIPEC may be successful in the treatment of selected CRC patients, its use remains controversial. Results from a 2018 randomized trial showed that HIPEC “does not improve survival over surgery alone and may increase complication rates”. Four new studies presented at the ESMO 22nd World Congress on Gastrointestinal Cancer held earlier this month found:

• Mitomycin C and oxaliplatin are two chemotherapy drugs used in HIPEC therapy. A Dutch observational study found no significant difference in survival outcomes between HIPEC patients given mitomycin C vs those receiving oxaliplatin.
• The addition of chemotherapy after CRS-HIPEC significantly improved overall survival when compared with active surveillance (close observation without active treatment) based on analysis of a Dutch nationwide registry.
• Results from a centralized program in Barcelona highlighted how proper selection of patients based on who is most likely to respond to HIPEC can achieve excellent disease outcomes. The team reported a median overall survival after CRS-HIPEC of almost 43 months in patients with peritoneal CRC metastases.
• Early findings from the ongoing randomized phase 3 trial CAIRO6, which is comparing CRS-HIPEC plus perioperative systemic therapy (chemotherapy given around the time of surgery) compared to CRS-HIPEC alone, suggest that systemic therapy induces better overall tumour responses.

Rather than discarding CRS-HIPEC as a useful treatment for certain subsets of CRC patients, these study findings suggest that identifying subgroups that are more likely to benefit from the treatment as well as gaining a better understanding of how the treatment fits in among other existing therapies could help to increase patient benefit from CRS-HIPEC.