 4.0 Basic trial design The proposed study will be a double-blinded, randomized controlled Phase III study to evaluate the effect of FV-guided surgery in patients diagnosed with severe dysplasia, carcinoma in situ and invasive squamous cell carcinoma and undergoing surgery treatment with an intent-to-cure. The trial will randomize 200 patients -100 in the FV arm using FV guided the surgery margin and 100 in the control arm using conventional white light approach. The trial period is 5 years - 2 years to complete accrual and 3 more years of follow-up. 