Most early-stage breast cancer patients in the U.S. get more radiation therapy than they need.  The Penn Medicine researchers who made this finding say it indicates medical professionals are either unaware of or are going against professional society guidelines about radiation treatment for early-stage patients.  Randomized trials have shown only three weeks of a higher-dose form of radiation are needed for these patients. However, about two-thirds of early-stage breast cancer patients have radiation for twice that long following surgery.  The study findings were published in the "Journal of the American Medical Association."