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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