In routine breast cancer screening, how frequently is screening offered to eligible individuals?

• A. Every 1 year
• B. Every 2 years
• C. Every 3 years
• D. Every 4 years

Answer: (C)

Screening intervals are set to balance early detection with minimizing harms and resource use. For routine breast cancer screening in the eligible population described, the program invites individuals about every three years. This interval aims to catch cancers reasonably early—before they become advanced—without the added harms that come with more frequent screening, such as false positives, unnecessary biopsies, anxiety, and higher radiation exposure. A yearly interval would increase these harms and costs without a proportional improvement in outcomes, while a shorter two-year gap is used in some guidelines but not in this context, and a four-year gap would raise the risk of cancers being detected at a more advanced stage.