The term “risk” is used to refer to a number or percentage that describes how likely a certain event is to occur. When we talk about factors that can increase or decrease the risk of developing breast cancer, either for the first time or as a recurrence, we often talk about two different types of risk: absolute risk and relative risk.
Absolute risk
Absolute risk is used to describe an individual’s likelihood of developing breast cancer. It is based on the number of people who will develop breast cancer within a certain time period. Absolute risk also can be stated as a percentage.
When we say that 1 in 8 women in India, or 13%, will develop breast cancer over the course of a lifetime, we are talking about absolute risk. On average, an individual woman has a 1-in-8 chance of developing breast cancer over an 80-year lifespan.
The absolute risk of developing breast cancer during a particular decade of life is lower than 1 in 8. The younger you are, the lower the risk. For example:
From age 30 to 39, absolute risk is 1 in 233, or 0.43%. This means that 1 in 233 women in this age group can expect to develop breast cancer. Put another way, your odds of developing breast cancer if you are in this age range are 1 in 233.
From age 40 to 49, absolute risk is 1 in 69, or 1.4%.
From age 50 to 59, absolute risk is 1 in 38, or 2.6%.
From age 60 to 69, absolute risk is 1 in 27, or 3.7%.
As you can see, the older you are, the higher your absolute risk of breast cancer. Keep in mind that these numbers and percentages are averages for the whole population. Your individual breast cancer risk may be higher or lower, depending on a number of factors, including family history, reproductive history (such as menstrual and childbearing history), race/ethnicity, and other factors.
Take family history, for example. The absolute risk of breast cancer is much higher for women who have inherited mutations in the genes known as BRCA1 or BRCA2. Their absolute risk over the course of a lifetime ranges from 40-85%. This means that out of every 100 women who have these mutations, anywhere from 40 to 85 of them can expect to develop breast cancer should they live to age 80.
If you have breast cancer, absolute risk also can be used to describe the likelihood of a certain treatment outcome or the course of the disease. For example, suppose that, based on the characteristics of the breast cancer (stage, grade, other test results), your age and medical history, and the treatments you have, your doctor tells you that your likelihood of disease-free survival at 5 years — being alive with no evidence of breast cancer — is 90%. This means that your absolute risk of having the breast cancer come back within 5 years is 10%, or 1 in 10. In other words, 1 out of 10 women with similar characteristics and the same treatment plan can expect to have a recurrence within that time frame. Nine out of 10, or 90%, would not.
Relative risk
Relative risk is a number or percentage that compares one group’s risk of developing breast cancer to another’s. This is the type of risk frequently reported by research studies, which often compare groups of women with different characteristics or behaviors to determine whether one group has a higher or lower risk of breast cancer than the other (either as a first-time diagnosis or recurrence).
Understanding relative risk can help you answer an important question: If I make certain lifestyle choices or have certain treatments, how much will I increase or decrease my risk of developing breast cancer or having a recurrence?
Saturday, January 2, 2010
what is breast cancer ?
Breast cancer is an uncontrolled growth of breast cells. To better understand breast cancer, it helps to understand how any cancer can develop.
Cancer occurs as a result of mutations, or abnormal changes, in the genes responsible for regulating the growth of cells and keeping them healthy. The genes are in each cell’s nucleus, which acts as the “control room” of each cell. Normally, the cells in our bodies replace themselves through an orderly process of cell growth: healthy new cells take over as old ones die out. But over time, mutations can “turn on” certain genes and “turn off” others in a cell. That changed cell gains the ability to keep dividing without control or order, producing more cells just like it and forming a tumor.
A tumor can be benign (not dangerous to health) or malignant (has the potential to be dangerous). Benign tumors are not considered cancerous: their cells are close to normal in appearance, they grow slowly, and they do not invade nearby tissues or spread to other parts of the body. Malignant tumors are cancerous. Left unchecked, malignant cells eventually can spread beyond the original tumor to other parts of the body.
The term “breast cancer” refers to a malignant tumor that has developed from cells in the breast. Usually breast cancer either begins in the cells of the lobules, which are the milk-producing glands, or the ducts, the passages that drain milk from the lobules to the nipple. Less commonly, breast cancer can begin in the stromal tissues, which include the fatty and fibrous connective tissues of the breast.Over time, cancer cells can invade nearby healthy breast tissue and make their way into the underarm lymph nodes, small organs that filter out foreign substances in the body. If cancer cells get into the lymph nodes, they then have a pathway into other parts of the body.
Breast cancer is always caused by a genetic abnormality (a “mistake” in the genetic material). However, only 5-10% of cancers are due to an abnormality inherited from your mother or father. About 90% of breast cancers are due to genetic abnormalities that happen as a result of the aging process and the “wear and tear” of life in general.
While there are steps every person can take to help the body stay as healthy as possible (such as eating a balanced diet, not smoking, limiting alcohol, and exercising regularly), breast cancer is never anyone's fault. Feeling guilty, or telling yourself that breast cancer happened because of something you or anyone else did, is not productive.
Cancer occurs as a result of mutations, or abnormal changes, in the genes responsible for regulating the growth of cells and keeping them healthy. The genes are in each cell’s nucleus, which acts as the “control room” of each cell. Normally, the cells in our bodies replace themselves through an orderly process of cell growth: healthy new cells take over as old ones die out. But over time, mutations can “turn on” certain genes and “turn off” others in a cell. That changed cell gains the ability to keep dividing without control or order, producing more cells just like it and forming a tumor.
A tumor can be benign (not dangerous to health) or malignant (has the potential to be dangerous). Benign tumors are not considered cancerous: their cells are close to normal in appearance, they grow slowly, and they do not invade nearby tissues or spread to other parts of the body. Malignant tumors are cancerous. Left unchecked, malignant cells eventually can spread beyond the original tumor to other parts of the body.
The term “breast cancer” refers to a malignant tumor that has developed from cells in the breast. Usually breast cancer either begins in the cells of the lobules, which are the milk-producing glands, or the ducts, the passages that drain milk from the lobules to the nipple. Less commonly, breast cancer can begin in the stromal tissues, which include the fatty and fibrous connective tissues of the breast.Over time, cancer cells can invade nearby healthy breast tissue and make their way into the underarm lymph nodes, small organs that filter out foreign substances in the body. If cancer cells get into the lymph nodes, they then have a pathway into other parts of the body.
Breast cancer is always caused by a genetic abnormality (a “mistake” in the genetic material). However, only 5-10% of cancers are due to an abnormality inherited from your mother or father. About 90% of breast cancers are due to genetic abnormalities that happen as a result of the aging process and the “wear and tear” of life in general.
While there are steps every person can take to help the body stay as healthy as possible (such as eating a balanced diet, not smoking, limiting alcohol, and exercising regularly), breast cancer is never anyone's fault. Feeling guilty, or telling yourself that breast cancer happened because of something you or anyone else did, is not productive.
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