Breast Cancer Risk

The “Red Book,” officially known as the “Guidelines for Preventive Activities in General Practice,” categorizes breast cancer risk into three groups: low, moderate, and high.

  1. Low Risk: Most women fall into this category, with a lifetime risk of less than 4%.
    1. This group typically includes women with
      1. no confirmed family history of breast cancer
      2. one first-degree relative diagnosed with breast cancer at age 50 or older
      3. one second-degree relative diagnosed with breast cancer at any age
      4. two second-degree relatives on the same side of the family diagnosed with breast cancer aged 50 or older, or
      5. two first-degree or second-degree relatives diagnosed with breast cancer aged 50 or older but on different sides of the family.
      6. The relative risk of breast cancer up to 75 years of age for this group is between 1:11 and 1:8​​.
  2. Moderately Increased Risk: This group constitutes less than 4% of the female population.
    1. It includes women with
      1. one first-degree relative diagnosed with breast cancer before age 50
      2. two first-degree relatives on the same side of the family diagnosed with breast cancer, or
      3. two second-degree relatives on the same side of the family diagnosed with breast cancer, at least one of whom was diagnosed before age 50.
      4. The relative risk of breast cancer for this group up to 75 years of age is between 1:8 and 1:4​​.
  3. High Risk: Women in this category are at a risk more than 3 times the population risk.
    1. This group includes women with
      1. additional relatives with breast or ovarian cancer, breast cancer diagnosed before age 40, bilateral breast cancer, both breast and ovarian cancer in the same woman,
      2. Ashkenazi Jewish ancestry,
      3. breast cancer in a male relative,
      4. one first-degree or second-degree relative diagnosed with breast cancer before age 45 plus another first-degree or second-degree relative on the same side of the family with sarcoma (bone/soft tissue) aged under 45, or members of a family in which a high-risk breast cancer gene mutation has been established​​.

For women at moderate or high risk, additional interventions such as risk-reducing medication (moderate and high risk) and risk-reducing surgery (high risk) are available. Referral to specialist genetic assessment is recommended for women assessed at high risk​​.