How To Calculate Your Risk For Breast Cancer

Using known risk factors for breast cancer,				people how lifestyle can alter their risk of breast
mathematical models can be developed to help				cancer. It also cannot be used in breast cancer
answer important questions. These mathematical				survivors, in patients with DCIS, LCIS, or people who
models are useful tools for researchers and for				carry one of the BRCA genes.
patients as follows:				BRCAPRO model: This is a statistical model available
- 1. Research on risk factors - The Claus risk				as a computer program that uses two different
assessment model was used to discover the				algorithms to evaluate family history and helps a
subpopulation of people who had an autosomal				doctor determine the likelihood of finding either a
dominant genetic allele that increased their risk from				BRCA1 mutation or a BRCA2 mutation in a family.
10% to 92%. This led to the discovery of the BRCA				The results of this can be used to determine if BRCA
genes associated with breast, ovarian, and prostate				testing is indicated. This is very useful in light of the
cancer.				high cost of BRCA testing ($3,000). None of the
- 2. Clinical trial eligibility - The Gail risk assessment				nonhereditary risk factors can yet be incorporated
model was developed to help researchers determine				into the model, however. In a comparison of four
who to enroll in the NSAPB Breast Cancer Prevention				different methods for estimating breast cancer risk in
Trialswhere chemoprevention was shown to reduce				patients with a family history of breast cancer, the
breast cancer risk.				BRCAPRO model was the least accurate. It
- 3. Guidelines for doing BRCA testing - BRCA testing				predicted only 49% of the breast cancers that
is very expensive and practically worthless if done on				actually occurred in the screened group of patients
everyone (because it is so rare to be homozygous				with a family history of breast cancer.
for BRCA1 or BRCA2). Mathematical models such as				Harvard Center for Cancer Prevention Risk
the BRCAPRO, BOADICEA, and Tyrer-Cuzick models				Assessment Tool: This is another breast cancer risk
can help determine what patients should undergo				assessment tool that includes more lifestyle factors
BRCA testing. The decision for testing is usually made				than the NCI or Gail Model tools. It has not been
when one of these models predicts a 10% or				studied as extensively as the Gail Model or the
greater chance that there is a mutation of the				simplified NCI model, but it is promising in that it
BRCA1, BRCA2, or both genes.				includes many lifestyle factors that people can do to
- 4. Guidelines for doing MRI screening for breast				modify their risk of developing cancer. It is also an
cancer - MRI screening for breast cancer is not a				on-line questionnaire that can be used by both
cost effective screening test for the general				women and men to estimate their breast cancer risk.
population, but in specific groups, there are clear cut				Making all this practical
reasons to do so. In general, screening MRI is
recommended for women with 20-25% or greater				Now after a thorough and confusing
lifetime risk of breast cancer. The BRCAPRO and				discussion of all these statistical models, it's time to
Tyrer-Cuzick models have been used to help make				make all this information practical. What is the best
clinical decisions about ordering MRIs for breast				way to help a patient accurately assess her risk of
cancer screening.				breast cancer and if possible, show her what positive
- 5. Guidelines for breast cancer therapy - The Gail				factors are reducing her risk and what negative
model is used clinically to helpdetermine who should				factors can be changed to reduce her risk? If
be put on tamoxifen or raloxifene for				possible, it would also be great to show the patient
chemoprevention. Other models have been used to				the value and indications for testing, imaging,
help make decisions about breast cancer risk				chemoprevention, and in some cases surgery. A
reduction with prophylactic mastectomy.				discussion of the practical aspect of each of these is
For these reasons, it is important to understand				addressed in a Q & A format below:
these models. These models are collectively refered				Q: What (free) online programs can be used to help a
to as "risk assessment tools". The following				patient assess their risk of breast cancer?
paragraphs summarize the most popular and most				A: Several of the risk assessment tools mentioned
widely used risk assessment tools. Keep in mind				above can be accessed for free by the public. Here
that none of these risk assessment tools apply to				are the tests and their websites:
breast cancer survivors. No mathematical model has
been widely accepted to determine cancer risk in				- 1. Your Disease Risk - English version:
cancer survivors.				This is a great interactive questionnaire that calculates
General Risk Assessment Tools				five-year and lifetime risk of breast cancer developed
Gail Model: The Gail model is a validated				by the Harvard Center for Cancer Prevention and
risk-assessment model that focuses primarily on				made public online in 2000. In 2005, they launched
nonhereditary risk factors, with limited information on				the Spanish version of the site, "Cuidar de su Salud".
family history. It was developed by scientists at the				The risk calculator includes lifestyle factors such as
National Cancer Institute and the National Surgical				weight, dietary vegetables, alcohol intake, as well as
Adjuvant Breast and Bowel Project (NSABP) to				Jewish ethnicity. It does not include other
assist health care providers in discussing breast				ethnicities, however, and is not accurate for BRCA
cancer risk to determine their eligibility for the Breast				mutation carriers or breast cancer survivors. Despite
Cancer Prevention Trial. The tool allows one to				these issues, this is by far the best free online risk
project a woman's individual estimate of breast				calculator since it is very interactive and gives you a
cancer risk over a five-year period of time and over				personalized description of your risk in the form of a
her lifetime. It also compares the woman's risk				colored bar graph, which they can electronically
calculation with the average risk for a woman of the				manipulate to experience "virtual" risk reduction. The
same age. The Gail Model is an on-line quiz that has				bar graph is a seven-level scale that compares users
13 questions and is interactive. This calculator is				to a typical man or woman your age. Users learn
based on published risk statistics and methods				where to focus their prevention efforts and how to
gathered from peer-reviewed journals, and has been				make lifestyle changes by "clicking on" personalized
extensively tested for its validity.				strategies. With each click, the bar graph shrinks,
				and the user watches his/her predicted risk drop.
�				This is a great concept to motivate people to
				participate and comply with lifestyle modification
The major limitation of the Gail model is the inclusion				measures.
of only first-degree relatives, which results in				- 2. The NCI Risk Assessment Tool -regular web:
underestimating risk in the 50% of families with				This is the easy to use, on-line questionnaire
cancer in the paternal lineage and also takes no				based on a modified Gail model that also includes
account of the age of onset of breast cancer. It				ethnicity. It does not factor in a personal history of
may underestimate risk in certain groups, such as				breast cancer, DCIS, or LCIS. It does not account
obese patients.				for other factors such as BRCA status, hormonal
�				replacement therapy, lifestyle factors, breast feeding,
National Cancer Institute Model: The NCI risk				menopause, or mammographic density. Despite
assessment tool is essentially a simplified Gail Model				these issues, it is a very useful tool that gives a
that also factors in race. Race is a factor in				woman her five-year and lifetime risk of breast
determining breast cancer risk but is excluded when				cancer. It is the only risk assessment tool that can
determining eligibility for clinical trials. This tool is				be used via mobile handheld devices (any type). A
probably the most popular risk assessment tool				version of this can be downloaded for PDAs with
available to the public as an on-line, interactive risk				Windows Pocket PC operating system as well.
calculator. The on-line quiz is a shorter, nine-point				Q: What programs can be used to help a doctor
questionnaire that includes multiple factors, giving a				make decisions about ordering a breast MRI?
woman her future five-year risk of breast cancer and
her lifetime risk of breast cancer.				A: The American Cancer Society has developed
�				some very good guidelines for breast cancer
The NCI tool does not account for a lot of risk				screening with MRI. It should be emphasized that
factors that can be modified. For this reason, it is				MRI is an adjunct to mammography, not a
difficult to use this test as a motivation tool to show				replacement.

Sibley Radonc

How To Calculate Your Risk For Breast Cancer