Neoadjuvant chemoradiotherapy (NACRT) prior to surgery for lower gastrointestinal (colon and rectal) cancer is associated with improved survival, but also adversely affects physical fitness, potentially rendering patients unfit for major surgery or increasing the risk of adverse outcome (death and serious complications) after major surgery. The investigators aim to obtain pilot data showing that neoadjuvant chemoradiotherapy (NACRT)reduces objectively measured exercise capacity (fitness).

Purpose: To evaluate the effects of chemoradiotherapy on pre-operative fitness of patients prior to major colorectal cancer surgery.

Design: Patients will act as their own case-control.

Patients will be consented at the earliest available opportunity following the decision that they have surgically treatable disease and they consent to pre-operative NACRT. Consent for the study will be gained as an outpatient. At "visit 1" patients will undergo CPET, as is our current standard practice, prior to commencing neoadjuvant chemoradiotherapy. As part of the assessment, they will have pulmonary function testing (static lung volumes, lung diffusing capacity). They will then undergo 6 weeks of long course NACRT, as is standard current practice at our institution. At "visit 2", approximately four to six weeks following chemoradiotherapy another CPET test will be repeated. This is also current standard practice at our institution. Data from visit 1 and visit 2 will be compared in a paired manner. A statistician will be consulted to assess the degree of normality of the data, the statistical tests to use, and for power calculations. At no point will any treatments be postponed or changed solely for the purposes of collecting data for the research.

Inclusion Criteria:

• All patients listed to undergo neoadjuvant chemoradiotherapy for downstaging of colorectal cancer, with a view to undergo elective colorectal surgery at Aintree University Hospitals.

Exclusion Criteria:

• Unable to consent.
• Under 18 years of age.
• Significant ischaemic changes of >1.5mm symptomatic and > 2mm asymptomatic observed on routine cardiopulmonary exercise test.
• Any other absolute contraindications to CPET based on the ATS guidelines.

Colorectal cancer is the third commonest cause of cancer related death (after breast and lung cancer) in the United Kingdom and the second commonest in non smokers. Around 100 new cases of colorectal cancer are diagnosed each day in the UK. In 2002 there were 34,889 new cases of colorectal cancer diagnosed in the United Kingdom, and approximately 17,000 deaths (CRUK 2006). Almost three quarters of bowel cancer cases occur in people aged 65 and over. Within England, mortality rates are generally higher in the north of the country.