I agree with essentia. Since cancer is a contraindication for so many treatments, share with your client that you would love to treat her, but for her safety you would want clearance from her doctor. If she isn't under current treatment at this time and there are no visible signs or complaints of sensitivity there shouldn't be an issue. But I would err on the side of caution to cover yourself. I would also ask what her desired goals are in terms of the procedure... I mean it is possible you could get great results with enzymes.