Aims and background: Screening by mammography has been shown to be effective in reducing breast cancer mortality. We present the results of a mammographic and clinical screening program carried out in an Italian health district.
Methods: The first screening round started in June 1987 and ended in July 1990, and 25,100 women between the age of 50 and 60 years were invited. The second screening round invited 34,332 women between the age of 50 and 64 years and was carried out from September 1990 to September 1993. Women with positive or equivocal results at palpation or mammography were referred for immediate diagnostic assessment followed by surgery, when required.
Results: The attendance rate was 67.3% at the first and 62.1% at the repeat screening. At the first screening, 206 biopsies were advised and 197 were performed; 129 of the 197 were found to be malignant. At repeat screening, 248 biopsies were recommended, 208 were performed, and 125 were found to be malignant. The cancer detection rate was 7.7 per thousand at the first and 5.9 per thousand at repeat screening. Of 129 cancers, 107 (83.0%) were T1 at first screening; 6.2% were in situ carcinomas. Axillary lymph nodes were histologically positive in 24% of cases. At repeat screening, 77.6% (97/125) of cancers were T1; 11.2% were in situ carcinomas. Positive axillary lymph nodes were found in 16.8% of cases.
Conclusions: The attendance to screening was satisfactory. A higher frequency of small tumors (83.0%) was found at first screening than before the introduction of screening (56.6%). A marked difference in lymph node positivity (24.0% vs 40.6% in the pre-screening era) was also observed. Such a difference was even more evident at repeat screening. Quality standards of the screening in our study proved to be higher than those currently recommended. The reported results are encouraging, also considering the greater chance for conservative treatment.