[Breast cancer incidence related with a population-based screening program].

Area of Science:

• Oncology
• Public Health
• Epidemiology

Background:

• Population-based breast cancer screening programs aim to detect cancer early.
• Understanding the impact of screening participation on cancer incidence and stage is crucial for program evaluation.

Purpose of the Study:

• To compare breast cancer cumulative incidence, time evolution, and stage at diagnosis between women who participated and those who did not in a population-based screening program.

Main Methods:

• A cohort study analyzed breast cancer incidence using data from a population-based cancer registry.
• The study included women from the target population of the screening program, with data spanning from 1999 to 2010.

Main Results:

• Participants had a significantly higher relative risk for in situ breast cancer (2.98) compared to non-participants.
• Participants were diagnosed at earlier stages (Stage I: RR 2.47) with a lower likelihood of lymph node involvement (RR 2.11).
• Both groups showed decreasing annual percent changes in incidence over time, with steeper initial increases in participants.

Conclusions:

• Breast cancer screening participation was associated with an increased incidence of in situ cancers, but not invasive or total cancers.
• Screening led to earlier diagnoses of breast cancer among participants.