How Can Persistent Verruca Be Treated?

I have had a persistant verucca for over 10 years now and have tried creams, gels, freezing, acids and all the hocus pocus stuff off the web to get rid of it, my doctor has told me there is nothing more he does for them except freeze them off and it is probably best left alone as it has not worked. The thing is it is spreading and i dont want to end up with a foot full of them is there anything you can suggest? thank you