Breast cancer is the most frequent cancer among women in the industrialized world, and screening-systematic examination of asymptomatic populations-is increasingly a part of public health services. In Norway a screening program for breast cancer was initiated in 1996 and became nationwide in 2004 (Cancer Registry of Norway 2005). The screening program biannually invites all women aged 50 through 69 to mammography. Women receive a letter of invitation with a preset appointment for the examination. Nearly 80 percent of those invited participated during the fi rst round of public screening, excluding women who sought mammograms through private clinics (Hofvind 2005). In part, fear of cancer, along with the old slogan “Early detection saves lives” (Lerner 2001), might have contributed to the high participation rate, because mammography screening is widely viewed as benefi cial (Sætnan 1992).