Optimum Timing for Surgery After Pre-operative Radiotherapy 6 vs 12 Weeks

Is Greater Downstaging and Tumour Regression Observed When Surgery is Delayed to 12 Weeks After Completion of Chemoradiotherapy vs 6 Weeks?

The aim of this study is to determine whether greater rectal cancer downstaging and regression occurs when surgery is delayed to 12 weeks after completion of radiotherapy/chemotherapy compared to 6 weeks.

Hypothesis: Greater downstaging and tumour regression is observed when surgery is delayed to 12 weeks after completion of CRT compared to 6 weeks.

Inclusion Criteria:

• Aged > 18
• Informed written consent
• Histological confirmation of adenocarcinoma of rectum
• Undergoing pre-operative radiotherapy/ chemotherapy
• Completion of pre-operative treatment

Exclusion Criteria:

• Aged < 18
• Absence of pre-operative RT/CT
• Medical/ psychiatric conditions that compromise the patients ability to give informed consent
• Contra-indications to MRI, i.e. hip prothesis, cardiac pacemaker