Principles in mass screening for breast cancer

The only proven means to reduce mortality from breast cancer is detection of the disease when it is still localized to the breast. Such a cancer is usually without signs or symptoms and often not even palpable and can be detected only through mass screening. The H.I.P. study has demonstrated a 30% reduction in mortality in a randomized study group compared to a matched control. The reduction has persisted over 14 years of follow up. Questions of potential hazard from x-ray radiation, questionable significant benefit in women under 50 years, cost and motivation are discussed.