Pre-operative NLR may represent a simple method of identifying colorectal cancer patients with a poor prognosis pre-operatively.

NLR > or =9.3 on the first post-operative day is associated with an increased risk of complications. This simple derivation of routinely available data helps to identify patients at high-risk of complications, allowing targeted preventive measures.

Fluid prescription practice in general surgical units is sub-optimal, resulting in avoidable iatrogenic complications. Involvement of senior staff, education and possibly the introduction of prescribing protocols may improve the situation.