A significant proportion of colorectal cancer patients with T4 disease will go on to develop peritoneal metastases, often without involvement in other area. Clinical and pharmacokinetic data hypothesize that the effectiveness of intraperitoneal chemotherapy is greatest when the disease is microscopic but there is insufficient robust evidence to ascertain whether the addition of HIPEC for high-risk colorectal cancers provides better control of local recurrence over systemic therapy.