Breast cancer factors
- Age
- The risk of breast cancer increases with age because the cells in the breast undergo changes over time. About 2 out of 3 invasive breast cancers are found in women aged 55 or older, highlighting the importance of regular screening for older women. It is believed that cumulative exposure to risk factors over a lifetime contributes to the higher incidence in older women.
- Gender
- Breast cancer primarily affects women, with over 99% of cases occurring in females. This is primarily due to the presence of breast tissue in women and the hormonal influences on breast development and function. However, it’s important to note that breast cancer can also affect men, although it is relatively rare.
- Family history and genetics
- Having a first-degree relative (mother, sister, or daughter) with breast cancer approximately doubles a woman’s risk. This suggests that genetic factors play a role in the development of breast cancer. Inherited mutations in specific genes, such as BRCA1 and BRCA2, significantly increase the risk of both breast and ovarian cancers. Women with these mutations have higher chances of developing breast cancer compared to the general population.
- Personal history of breast cancer or other breast conditions
- A woman with a history of breast cancer has a higher risk of developing a new breast cancer compared to someone who has never had the disease. This may be due to genetic factors, environmental exposures, or other shared risk factors. Additionally, some benign breast conditions, such as atypical hyperplasia, slightly increase the risk of developing breast cancer. Regular follow-up and monitoring are essential for women with a history of breast conditions.
- Hormonal factors
- Hormonal factors, such as age at menarche (first menstruation) and age at menopause, influence breast cancer risk. Women who started menstruating early (before age 12) or went through menopause late (after age 55) have a slightly higher risk of breast cancer. This is likely due to longer exposure to estrogen, which can promote the growth of breast cells.
- Hormone replacement therapy (HRT) that combines estrogen and progesterone, commonly used to manage menopausal symptoms, increases the risk of breast cancer. However, the risk appears to decline and return to normal within five years of stopping HRT.
- Lifestyle factors
- Excessive alcohol consumption is associated with an increased risk of breast cancer. The risk rises with the amount of alcohol consumed. It is recommended to limit alcohol intake to reduce breast cancer risk.
- Engaging in regular physical activity can help reduce the risk of breast cancer. Women who are physically active have a lower risk compared to inactive women. Exercise is believed to have a positive impact on hormone levels, weight control, and immune function, which may contribute to reducing breast cancer risk.
- Obesity, particularly after menopause, is linked to an increased risk of developing breast cancer. Adipose tissue produces estrogen, and higher levels of estrogen can promote the development of breast cancer cells.
- A diet high in saturated fats may contribute to an increased risk of breast cancer. Consuming a balanced diet that includes a variety of fruits, vegetables, whole grains, and lean proteins is recommended for maintaining overall health, including breast health.
- Dense breast tissue
- About 40% of women aged 40 and older have dense breast tissue, which refers to the proportion of fibrous and glandular tissue compared to fatty tissue in the breasts. Women with dense breasts have a higher risk of developing breast cancer compared to those with less dense breasts. Dense breast tissue can make it more challenging to detect tumors on mammograms, as both dense tissue and tumors appear white on the image.
- Radiation exposure
- Women who received radiation therapy to the chest area as children or young adults, such as for the treatment of Hodgkin lymphoma, have a significantly increased risk of developing breast cancer later in life. The radiation exposure during treatment can damage DNA in the cells of the breast tissue, leading to an elevated risk of cancer.