According to a new study from the University of Pennsylvania, two-thirds of women who have lumpectomies for breast cancer are receiving radiation treatment that lasts nearly twice as long as necessary. The conventional, longer treatment lasts 5 to 7 weeks. But 4 rigorous studies and guidelines from a leading radiology society conclude that 3 to 4 weeks of more intense radiation is just as effective. Via The New York Times. Posted December 10, 2014.