This paper forecasts the consequences of scientific progress in cancer for total Medicare spending between 2005 and 2030. Because technological advance is uncertain, widely varying scenarios are modeled. A baseline scenario assumes that year 2000 technology stays frozen. A second scenario incorporates recent cancer treatment advances and their attendant discomfort. Optimistic scenarios analyzed include the discovery of an inexpensive cure, a vaccine that prevents cancer, and vastly improved screening techniques. Applying the Future Elderly Model, we find that no scenario holds major promise for guaranteeing the future financial health of Medicare.