Lower GI 2017

The Royal Marsden

The Endpoint Local Failure

Powered for unacceptable failure rate – 80% power <15% local recurrence at 2 years. STOPPING RULE - ≥5 regrowth resulting in positive pathologic CRM – trial ends

Safe deferral

90% power - ≥10% defer - expected to be at least 25% success ≥ 11 of 59 patients safely defer surgery at 2yrs