# How to calculate the risk of breast cancer

Using the 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 Claus risk assessment model was used to detect subgroup who had inherited dominant genetic allele that increased their risk by 10% to 92%. This led to the discovery of BRCA genes associated with breast, ovarian, and prostate cancer.

2 clinical trial eligibility – The Gail risk model was developed to help researchers determine who to enroll in NSAPB Breast Cancer prevention trials

where chemoprevention was shown to reduce the risk of breast cancer.

3. Guidelines for doing BRCA testing – BRCA testing is very expensive and practically worthless if done at all (because it’s so rare to be homozygous for BRCA1 or BRCA2). Mathematical models such BRCAPRO, BOADICEA and Tyrer-Cuzick model can help determine which patients should undergo BRCA testing. The decision to test is usually done when one of these models predicts a 10% or greater probability that there is a mutation in BRCA1, BRCA2, or both genes.

4. Guidelines for doing MRI screening for breast cancer – MRI screening for breast cancer is not cost effective screening for the public, but in special populations, there are clear reasons cut to do it. In general, screening MRI is recommended for women with 20-25% or greater lifetime risk of breast cancer. The BRCAPRO and Tyrer-Cuzick models have been used to make clinical decisions about ordering MRIs for breast cancer screening.

5. Guidelines for the treatment of breast cancer – The Gail model is used clinically to help

decide who should be put on tamoxifen or raloxifene for chemoprevention. Other models have been used to make decisions about the breast cancer risk reduction with prophylactic mastectomy.

For these reasons, it is important to understand these models. These models are collectively referred to as “risk assessment tools”. The following paragraphs together the most popular and most used tools of risk assessment. Keep in mind that none of this risk assessment tool for breast cancer survivors. No mathematical model has been widely accepted to determine cancer risk of cancer survivors

General Risk Assessment Tools

Gail Model :. The Gail model is a validated risk assessment model that focuses primarily on nonhereditary risk factors, with limited information on genealogy. It was developed by researchers at the National Cancer Institute and the National Surgical Adjuvant treatment Breast and bowel Project (NSABP) to assist health care providers in discussing breast cancer risk to determine their eligibility for the Breast Cancer Prevention Trial. The tool allows one to shed a unique plan woman’s risk of breast cancer over five years and over a lifetime. It compares the risk premium for the calculation of the average woman’s risk of a woman of the same age. The Gail Model is in line quiz has 13 questions and is interactive. This calculator is based on published risk statistics and methods gathered from peer-reviewed journals, and has been extensively tested for its validity.

The major limitation Gail model is the inclusion of only first-degree relatives, which results in an underestimation of risk in 50% of families with cancer analyzes lineage and also takes no account of the age of onset of breast cancer. It may underestimate the risk in certain groups, such as obese

National Cancer Institute Model :. The NCI risk assessment tool is essentially a simplified Gail Model that also factors in the race. Race is a factor in determining the risk of breast cancer but are excluded when determining your eligibility for clinical trials. This tool is probably the most popular risk assessment tool available to the public that the line, interactive risk calculator. The online quiz is a shorter, nine-point questionnaire that includes more than one, giving the woman the future five-year risk of breast cancer and her lifetime her risk of breast cancer.

The NCI tool does not account for a lot of factors that can be changed. For this reason, it is difficult to use this test as a motivation tool to show people how life can change in breast cancer risk. It also can not be used in breast cancer survivors, patients with DCIS, LCIS, or people who carry one of the BRCA genes

BRCAPRO model :. This is a statistical model available as a computer program that uses two different algorithms to assess family history and help the doctor determine the probability of finding either a BRCA1 mutation or BRCA2 mutation in the family. Results can be used to determine if BRCA testing. This is very useful in view of the high cost of BRCA testing (\$ 3,000). None of nonhereditary risk factors can still be incorporated into the model, however. In a comparison of four different methods to assess the risk of breast cancer in patients with a family history of breast cancer BRCAPRO model was the least accurate. It predicted only 49% of breast cancer that actually occurred in the screened group of patients with a family history of breast cancer

Harvard Center for Cancer Prevention Risk Assessment Tool :. This is another breast cancer risk assessment tool that includes more lifestyle factors, but the NCI or Gail Model tools. It has not been studied as much as the Gail Model or the simplified NCI model, but it is promising in that it involves many aspects of life that people can do to change the risk of cancer. There is also an online questionnaire that can be used both men and women to assess their risk of breast cancer.

Making all this realistic

Now, after a thorough and confusing discussion of all these statistical models, it’s time to take all this information practical. What is the best way to help the patient accurately assess the risk of her breast and, if possible, to show her what positive factors are reducing risk, and what negative factors can change to reduce the risk of her? If possible, it would also be great to show the patient and indications for testing, imaging, chemoprevention, and in some cases surgery. A discussion of the practical aspects of each of these is addressed in the Q & A format below:

Q: What (free) online applications can be used to help the patient to evaluate the risk of breast cancer

A : Several risk assessment tools above can be obtained for free by the public. Here are the tests and their websites:

1. Disease Risk Your – English version www.diseaseriskindex.harvard.edu

This is a great interactive questionnaire that calculates five years and the lifetime risk of breast cancer developed by the Harvard Center for Cancer Prevention and made public online in 2000. In 2005, they launched a Spanish version of the site, “Cuida de su Salud”. The risk calculator includes lifestyle factors such as weight, diet, vegetables, alcohol, as well as Jewish origin. It does not include other nationalities, however, and is not entitled to BRCA mutation carriers or breast cancer survivors. Despite these issues, this is by far the best free online risk calculator where it is highly interactive and gives you a personalized description of guarantee in the form of colored histogram, they can work electronically to experience “real” risk distribution. The bar graph is a seven-point scale that compares users to a typical man or woman of your age. Users learn where to focus prevention efforts and how to make lifestyle changes by “clicking” personal strategies. With each click, the bar graph shrinks, and the user from his / her predicted risk drop. This is a great idea to encourage people to participate and be consistent with measures lifestyle changes.

2. NCI Risk Assessment Tool -regular web: www.cancer.gov/bcrisktool

This is easy to use, on-line questionnaire based on the modified Gail a model that also includes ethnicity. It does not take into account their history of breast cancer, DCIS or LCIS. It does not take into account other factors, such as BRCA status, hormone replacement therapy, lifestyle factors, lactation, menopause, or breast tissue density. Despite these issues, it is a very useful tool that gives a woman five years and its lifetime risk of breast cancer. There is a risk assessment tool that can be used on mobile handheld devices (any type). A version of this is available for download PDAs with Windows Pocket PC operating system as well

Q:.? What programs can be used to help the doctor to take the decision to order a breast MRI

A: The American Cancer Society has developed excellent guidelines for breast cancer screening with MRI. It should be emphasized that MRI is a complement to mammography, not a replacement. Some programs can be used to help in clinical decision making. Please look up the American Cancer Society website.