This study will investigate the effect of preoperative chemoradiotherapy on exercise capacity as measured by cardiopulmonary exercise testing in patients with colorectal cancer.

Chemoradiotherapy is associated with adverse effects. Patients with certain colorectal cancers undergo chemoradiotherapy prior to surgical resection. We intend to assess patient exercise capacity before and after chemoradiotherapy to assess whether this deteriorates. If there is a deleterious effect, this may affect operative outcome.

Inclusion Criteria:

• Age greater than 65
• Colorectal cancer requiring preoperative chemoradiotherapy

Exclusion Criteria:

• Inability to walk, or exercise on a bicycle or treadmill
• Inability to understand instructions for CPET testing
• ASA grade 4 or 5 (indicating severe cardiovascular co-morbidity and not expected to survive surgery)
• Contraindications to Exercise Testing
• Myocardial infarction occurring 10 days or less before CPX testing
• Symptomatic arrythmias
• Left Main Stem coronary disease of >50%
• Severe hypertension (SBP>180mmHg)
• Resting SpO2 <85%
• Acute cardiac inflammatory conditions (myocarditis, pericarditis)
• Unstable angina with symptoms within 4 days
• Dissecting aneurysm of aorta
• Acute pyrexial illness
• Thyrotoxicosis
• Syncopal episodes
• Lower limb thrombosis (arterial or venous)