Mortality and recurrence patterns of breast cancer patients diagnosed under a screening programme versus comparable non-screened breast cancer patients from the same population: analytical survey from 2002 to 2012.

Breast cancer screening programmes seem to bring about significant benefits, including decreased mortality, although they may also have some drawbacks such as false-negative and false-positive results. This study aims to compare the clinical outcome of a group of patients undergoing a breast cancer screening programme with that of a synchronous non-screened group of patients matched for age and follow-up period. We studied basic characteristics of epidemiology, immunohistochemistry, loco-regional relapse, distant metastases, disease-free interval and overall and specific mortality. We compared 510 patients in the screened group with 394 non-screened patients, along the period of 2002-2012. Screening was applied on a target population of 49,847 and was based on double-projection, double-read mammograms. Two years were allowed per round. Overall participation for the five rounds considered was 75.2%, with 86.5% coverage, and a total cumulative population of 123,445. The non-participant women amounted 40,794. Tumour detection rate for the screened women was 3.8 per thousand (475/123,445), while the corresponding rate for non-participants was 9.4 per thousand (382/40,797). Incidence of luminal A subtype was 15% higher in screened than that in non-screened patients (95% confidence interval (CI) 8-22%). Conversely, the triple-negative subtype was 6% higher in the non-screened group (95% CI 2-10%). Incidence of breast conservative treatments and sentinel node biopsies was significantly higher in the screened group. Overall mortality was 2.6 times higher in non-screened than that in screened group (95% CI 1.2-5.6) After 10 years of experience with our own screening programme, we believe that included patients receive a benefit versus comparable non-screened breast cancer patients, with acceptable benefit-risk relation.