A focal ablation assembly, used with an endoscope comprising an endoscopic tube, comprises a cryogenic catheter, a balloon and a reinforcing element. The cryogenic catheter is placeable within the endoscopic tube channel and has a distal end placeable at the distal end of the endoscopic tube. The balloon is mountable to the catheter distal end and extends distally of both of the distal ends. The reinforcing element at least partially defines the shape of the balloon in the expanded state. The balloon defines a balloon volume when expanded and has a thermally conductive therapeutic region which provides effectively no thermal insulation. In some examples the focal ablation assembly comprises a delivery catheter extending along the channel with a distal portion fluidly coupled to the balloon interior, whereby refrigerant can be introduced into the balloon interior and towards the therapeutic region by the delivery catheter.
