The role of palliative resection of the primary tumour in patients who present with metastatic colorectal cancer is unclear.

This study compared the incidence of major intestinal complications in such patients who received chemotherapy treatment with or without prior palliative resection of the primary tumour.

The incidence of intestinal obstruction, perforation, fistula formation, and gastrointestinal haemorrhage, and the requirement for abdominal radiotherapy in patients with metastatic colorectal cancer treated at a single institution over a 10 year period was determined.

Eighty two patients received initial treatment with chemotherapy without resection of the primary tumour (unresected group) and 280 patients had undergone prior resection (resected group). In the unresected group, the incidence of peritonitis, fistula formation, and intestinal haemorrhage was 2.4% (95% confidence interval (CI) 0.3-8.5%), 3.7% (95% CI 0.8-10.3%), and 3.7% (95% CI 0.8-10.3%), respectively, and was not significantly different from the resected group. Intestinal obstruction affected 13.4% (95% CI 6.9-22.7%) of patients in the unresected group and 13.2% (95% CI 9.2-17.2%) of patients in the resected group. More patients in the unresected group required >/=3 blood transfusions (14.6% v 7.5%; p=0.048) and abdominal radiotherapy (18.3% v 9.6%; p=0.03) than the resected group.

The incidence of major intestinal complications in patients with unresected colorectal cancer and synchronous metastases who receive initial treatment with chemotherapy is low. Chemotherapy may be successfully used as initial treatment for such patients with no increased risk of most major intestinal complications compared with patients who have undergone initial resection of the primary tumour.