It has been recently held by the High Court (in Janet Birch v University College London Hospital NHS Foundation Trust) that in some circumstances doctors had a duty to inform patients of not only the risks of the procedure to be undertaken but also the comparative risks of an alternative procedure if those risks were fewer. In this case a patient had a catheter angiogram which has a small risk of stroke associated with it. Unfortunately the patient had a stroke during the procedure. Although the patient had been told of the risk of stroke she had not been informed of the comparative risks of MRI scanning. Although this case extends further the duty of informed consent upon doctors in some circumstances it is logical that a patient cannot give fully informed consent if unaware of the fewer risks associated with an alternative procedure available.
The case can be accessed here.