Avoiding risk factors and increasing protective factors may help prevent cancer.
Avoiding cancerrisk factors such as smoking, being overweight, and lack of exercise may help prevent certain cancers. Increasing protective factors such as quitting smoking, eating a healthy diet, and exercising may also help prevent some cancers. Talk to your doctor or other health care professional about how you might lower your risk of cancer.
The treatment of cancer in children and adolescents may adversely affect their subsequent reproductive function. Germ cell survival may be adversely affected by radiation therapy and chemotherapy. Ovarian damage results in both sterilization and loss of hormone production because ovarian hormonal production is closely related to the presence of ova and maturation of the primary follicle. These functions are not as intimately related in the testis. As a result, men may have normal androgen production...
NCI'sBreast Cancer Risk Assessment Tool uses a woman's risk factors to estimate her risk for breast cancer during the next five years and up to age 90. This online tool is meant to be used by a health care provider. For more information on breast cancer risk, call 1-800-4-CANCER.
The following risk factors may increase the risk of breast cancer:
Endogenousestrogen is a hormone made by the body. It helps the body develop and maintain female sex characteristics. Being exposed to estrogen over a long time may increase the risk of breast cancer. Estrogen levels are highest during the years a woman is menstruating. A woman's exposure to estrogen is increased in the following ways:
Early menstruation: Beginning to have menstrual periods at age 11 or younger increases the number of years the breasttissue is exposed to estrogen.
Late menopause: The more years a woman menstruates, the longer her breast tissue is exposed to estrogen.
Late pregnancy or never being pregnant: Because estrogen levels are lower during pregnancy, breast tissue is exposed to more estrogen in women who become pregnant for the first time after age 35 or who never become pregnant.
Hormone replacement therapy/Hormone therapy
Hormones that are made outside the body, in a laboratory, are called exogenous hormones. Estrogen, progestin, or both may be given to replace the estrogen no longer produced by the ovaries in postmenopausal women or women who have had their ovaries removed. This is called hormone replacement therapy (HRT) or hormone therapy (HT) and may be given in one of the following ways:
Combination HRT/HT is estrogen combined with progesterone or progestin. This type of HRT/HT increases the risk of developing breast cancer. Women taking combination HRT/HT also may be more likely to have an abnormalmammogram. Studies show that when women stop taking estrogen combined with progesterone, the risk of getting breast cancer decreases.
Estrogen-only therapy may be given to women who have had a hysterectomy. Clinical trials studying whether estrogen-only therapy affects the risk of breast cancer have had mixed results. In women who have a uterus, estrogen-only therapy increases the risk of uterine cancer.
Exposure to Radiation
Radiation therapy to the chest for the treatment of cancers increases the risk of breast cancer, starting 10 years after treatment and lasting for a lifetime. The risk of developing breast cancer depends on the dose of radiation and the age at which it is given. The risk is highest if radiation treatment was used during puberty. For example, radiation therapy used to treat Hodgkin disease by age 16, especially radiation to the chest and neck, increases the risk of breast cancer.