Mammography screening for breast cancer: first year results from Helsinki and surroundings.

11,789 women aged 50-59 years were invited for screening by the mammography screening centre of the Cancer Society of Finland in Helsinki. 9829 women (83.37%) attended and 3.85% of those were recalled for further studies. After complete examination seventy-one women (0.72%) were referred for surgical biopsy and breast cancer was histologically detected in 44 (0.45%) of those screened. The proportion of Stage I + TIS breast cancers detected was 75%, and of Stage II or more advanced, 25%. With modern mammography techniques and proper training of technicians and radiologists, with double reading of all the films, it is possible to minimise both the recall rate and the number of women who are referred for surgical biopsy, and still find cancers in their early stages.