Breast Cancer Guidelines

I use the definition used in the NSABP chemoprevention trials NSABP-P01 and -P02. In those studies the Gail model was used and high risk was defined as a five year risk of 1.67 or greater. This number is the cut-off for referral for consideration for tamoxifen or raloxifene to decrease risk. The Gail model takes into account current age, ethnicity, age of first menstrual period, age of first live birth, family history of breast cancer (first degree relatives), number of excisional biopsies and whether or not atypia was found on those biopsies. Other models exist such as BRCAPRO, Claus, or Tyrer-Cuzick. The American Cancer Society recommends annual MRI for patients who have a lifetime risk of breast cancer of 20% or higher.

I am a pragmatist by nature, and I know that when I am on the phone with an insurance company to obtain pre-certification for a screening breast MRI for one of my patients, I will be asked the Gail model lifetime risk. Therefore this is the model I use most often, the calculator for which I carry in my pocket.

The model can underestimate risk when there is inherited predisposition, such as BRCA 1 or 2 positivity. As I'm sure many of the readers of this website know, female carriers of a deleterious mutation of BRCA 1 or 2 have a lifetime risk of breast cancer of 50-80%.