(This commentary was not written by CRD, but by the authors of the DH Register.) 1) The analysis deliberately takes an optimistic stance on most parameters included. The effect on the findings of more conservative assumptions is not explored. Very little is known about the progression of stage B disease (assumed 100% curable). 2) Costs of surgery were not included, inclusion would make screening less attractive. 3) Monte-Carlo simulation: modelling is careful but parameter uncertainties and optimistic selection make the accuracy of the findings questionable. Baseline mean disease progression (B to C) is 5 years, results changed very little using one and ten years. 4) The parameters investigated by sensitivity analysis and the ranges of values were not adequately justified. 5) The authors acknowledge the morbidity associated with surgery: incontinence (15%) and impotence (most).