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Biological Causes

The non-modifiable risk factors refer to the biological risk factors that women have no control over, as opposed to the modifiable risk factors.

Being Female

Being a woman is in itself a breast cancer risk factor as over 99% of cases of this cancer develop in women. The disease occurs in men in less than 1% of cases, and often these men are over 60 years old.

Growing Older

The risk of breast cancer increases with age. The longer a woman lives, the greater the likelihood that she will one day be affected by this disease. This type of cancer occurs most frequently in women between 50 and 69 years of age. Nevertheless, in almost one out of five cases, it affects women between 20 and 49. Approximately 20% of cases are diagnosed in older women.

Personal History of Breast Cancer

Women who have already had breast cancer are at a higher risk of getting it again, in the same breast or the other.

Having a Family History of Breast Cancer

The risk of developing breast cancer increases if one or more family members, from the maternal or paternal side, have already had breast cancer, particularly if the relative is female and was diagnosed before menopause. Furthermore, the greater the number of first-degree relatives (mother, father, sister, or daughter) who have had the disease, the greater the woman’s risk of developing breast cancer.

The risk is lower if the cancer occurred in a second-degree relative (grandmother, aunt, or niece), but is higher if the family member had cancer in both breasts (bilateral breast cancer) before menopause. The following family histories are also considered risk factors:

  • two or more family members affected by breast or ovarian cancer;

  • one family member affected by breast cancer and ovarian cancer;

  • one male family member affected by breast cancer.

It’s important to note, however, that most women with breast cancer have no family history of the disease. Be vigilant: if there is a history of breast cancer in your family, talk to your doctor.

Having Mutated Genes (BRCA1, BRCA2 or Other)

The genes we inherited may have mutated from one generation to the next, thus increasing the risk of developing breast cancer. Click here to learn more about mutated genes.

Early Menstruation

The onset of menstruation at an early age, that is before 12, extends the length of exposure to estrogen and other hormones, which increases the risk of breast cancer.

Late Menopause

The later the onset of menopause—for instance, after the age of 55—the longer the woman’s body is exposed to estrogen during her lifetime. This increases the risk of developing breast cancer.

Abnormal Cells Found in the Breast Tissue (Atypical Hyperplasia)

Atypical hyperplasia describes the presence of a large number of abnormal (atypical) cells in the breast tissue. Women diagnosed with atypical hyperplasia through a biopsy are at a higher risk of developing breast cancer.

Being Tall

Tall women are at a slightly higher risk of developing breast cancer after menopause than are small women. Diet during childhood and adolescence could be a possible explanation for this.