BACKGROUND: Screening can lead to earlier detection of breast cancer and thus to an improvement in survival. The authors studied the life expectancy of women with screen-detected invasive breast cancer (patients) compared with women invited to the breast cancer screening program in Nijmegen, the Netherlands (comparison group). METHODS: Each patient diagnosed between 1975 and 2006 was randomly age-matched with a woman invited in the same calendar year and free from breast cancer at the time of diagnosis of the patient. Survival analyses were performed to study differences in life expectancy. RESULTS: The life expectancy for 858 patients was 6 years shorter than for the comparison group, However, for 360 patients with small (<15 mm) invasive breast cancer, life expectancy was similar to that of the comparison group. In contrast, for patients detected with larger tumors (>= 15 mm) the life expectancy was 6 to 12 years shorter, depending on tumor size. Furthermore, life expectancy was modified by screening history. For patients who had a negative screening examination 2 years before the detection of their breast cancer, the difference in life expectancy from the comparison group became smaller for the larger tumor sizes (>= 15 mm). CONCLUSIONS: In conclusion, about 40% (360 of 858) of all women with invasive screen-detected breast cancer have the same life expectancy as women from the comparison group (reflecting the general population). For women diagnosed with larger tumors at diagnosis, life expectancy diminishes with increasing tumor size and is modified by screening history. Cancer 2010;116:586-91. (C) 2009 American Cancer Society.