Risk 2

The use of known risk factors for breast cancer, mathematical models can be developed to help answer important questions. These mathematical models are useful tools for researchers and patients as follows:

• 1. Research on risk factors - The risk assessment model of Santa Claus has revealed the subpopulation of people who had a genetic autosomal dominant allele which increased their risk by 10% to 92%. This led to the discovery of BRCA genes associated with breast, ovarian and prostate cancer.
• 2. Eligibility for clinical trials - The model of Gail risk assessment was developed to help researchers determine who enroll in breast cancer prevention trials NSAPB

where chemotherapy has reduced the risk of breast cancer.

• 3. Guidelines for BRCA testing - BRCA test is very expensive and practically worthless if it is for everyone (because it is so rare to be homozygous for BRCA1 or BRCA2). Mathematical models such as BRCAPRO, BOADICEA, and Tyrer-Cuzick models can help determine what patients have to undergo BRCA testing. The decision to test is usually made when one of these models predicted a 10% or more chance there is a mutation in BRCA1, BRCA2, or both genes.
• 4. Guidelines for Cancer Screening Breast MRI - MRI screening for breast cancer is not a cost effective screening test for the general population, but in specific groups, there are clearly defined reasons to do so. In general, screening MRI is recommended for women of 20-25% or greater risk of breast cancer. Models and Tyrer-Cuzick BRCAPRO have been used to help make clinical decisions about ordering the MRI for the detection of breast cancer.
• 5. Guidelines for the treatment of breast cancer - The Gail model is used clinically to help

models to determine who should be put on tamoxifen and raloxifene for chemoprevention. Others have been used to help make decisions about risk reduction of breast cancer with prophylactic mastectomy.

For these reasons, it is important to understand these models. These models are collectively referred to as "tools of risk assessment". The following paragraphs summarize the most popular and widely used tools for risk assessment. Keep in mind that none of these assessment tools risks apply to survivors of breast cancer. No mathematical model has been widely accepted for determining the risk of cancer among cancer survivors.

General Risk Assessment

Gail Model: The Gail model is a validated model for risk assessment that focuses primarily on non-hereditary risk factors, limited information on family history. It was developed by scientists at the National Cancer Institute and the National Surgical Adjuvant Breast and bowel Project (NSABP) to assist health care providers discuss the risk of breast cancer to determine their eligibility to test cancer Breast prevention. The tool allows to estimate the individual projects of a woman's risk of breast cancer over a period of five years of time and during his life. It also compares the calculated risk of women with average risk for a woman of the same age. The Gail model is an online quiz which has 13 questions and is interactive. This simulator is based on statistics published on the risks and methods gathered from scientific journals and has been tested for validity.

The major limitation of the Gail model is the inclusion of only first-degree relatives, which leads to underestimate risk in 50% of the fam.