[BBoingo]

Depends on how much the tumor mutates down the line. Most immunologic therapies and actions are based on specific markers antibodies can latch on to to mark cancer cells for destruction. With Cetusimab (generic name) you are already on a sort of immunologic treatment. It's a chimeric monoclonal antibody doing its antibody thing. Just taking a wild stab out to left field, the skin component of your reaction might be related to some sort of allergic-ish reaction to the mouse component of the cetusimab.