what are the risk factors of breast cancer? what are the risk factors of breast cancer? Doctors media



what are the risk factors of breast cancer?

breast cancer risk factors

Breast cancer risk factors

Breast cancer is the most common cause of death in middle-aged women in Western countries. In 2010, approximately one and three quarter million new cases were diagnosed worldwide.

In England and Wales, 1 in 12 women will develop the disease during their lifetime.

Risk factors of breast cancer are given below;


the most important risk factor is gender, only 1% breast cancer cases occur in men.


 Cancer is very rare before the age of 25 years. The peak age of cancer at the age of 75-80 years. Average age at diagnosis is 61 for white women, 56 for Hispanic women and 46 for African American women.

 Age of onset of menstruation: 

Women who started early period below 11 years of age have a20% increased risk compared with women who are more than 14 years of age at onset of menstruation.

 Age at first live birth: Women who experience a first full-term pregnancy at ages younger than 20 years have half the risk than women over the age of 35 at their first birth.

 First degree relative with breast cancer:

The risk of cancer increases with the number of affected first degree relatives (mother, sister, or daughter).

 Only 13% of women with breast cancer have one affected first-degree relatives.

Over 87% of women with family history will not develop breast cancer.

Most family risk is probably due to the interaction of gene and non-gene factor.

Race/ Ethnicity:

Non-Hispanic white women have the highest rates of breast cancer.
Variation in breast cancer genes across ethnic groups is responsible for different frequencies in different ethnic groups. BRCA1 and BRCA2
 Genes mutation are responsible for breast cancer.

Hormone (estrogen) exposure:

 postmenopausal hormone replacement therapy slightly increases the risk of breast cancer. Oral contraceptives are unlikely to increase the risk. 

Radiation exposure:

 Radiation to chest, whether due to cancer therapy, atomic bomb exposure, or nuclear accidents results in higher rate of cancer.

Cancer of the opposite breast or uterus endometrium:

Approximately 1% of women with breast cancer develop a second contralateral breast cancer per year.

Geographic influence:

Incidence of cancer is 4 to 7fold in USA & Europe than in other countries.


 Alcohol increases risk and coffee decrease the risk.


Risk is decrease in obese with women younger than 40 years due to association with anovulatory cycle & lower progesterone (hormone) level.

Increased risk in postmenopausal obese women due to estrogen synthesis in fat droplets


There is small protective effect for women who are physically active.

Breast feeding:

The longer women breastfeed, the greater the reduction in risk.


Cigarette smoking is not associated with cancer but is associated with the development of periductal mastitis or a sub areolar abscess.

Environmental toxins:

Organochloride pesticides have estrogenic effects of humans.

Read more :Warning signs of cancer

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