Why Is Postmenopausal Breast Cancer Common?

How does menopause affect breast cancer risk?

Early menopause may lower the risk of breast cancer, while late menopause (after age 55) increases the risk. In fact, on average breast cancer risk increases by about 3% per year of delay in menopause. 

This may be because the older you are when you start menopause, the more estrogen exposure you have had, which increases breast cell growth and division. For the same reason, starting menstruation early also increases your risk of breast cancer since this increases the total number of years you are exposed to estrogen.

Furthermore, as estrogen levels produced from the ovaries are reduced after menopause, fat cells act as the primary site of estrogen secretion. Therefore, women who have a higher body mass index, i.e. obese and overweight women, tend to have a higher risk of breast cancer. Hormone replacement therapy can also increase breast cancer risk in postmenopausal women.

How fast does breast cancer grow postmenopause?

Estrogen receptor-positive breast cancers, also called ER-positive breast cancer, tend to grow slowly after menopause due to the fall in estrogen levels. Studies suggest that postmenopausal women have a better prognosis with a lower chance of breast cancer recurrence. Also, the cancer tends to be less deadly and requires less aggressive management. An ER-positive breast cancer can be treated with medications that block the effect of estrogen on cancer cells. 

Some postmenopausal women, however, may have triple-negative breast cancer, which means that the breast cancer cells do not have estrogen and progesterone receptors on their surface, and they do not have an excess of another protein called human epidermal growth factor receptor-2 (HER-2). HER-2 protein also acts as a target for certain cancer medications. A triple-negative cancer tends to be more aggressive, spreads faster, and has fewer treatment options. It occurs in about 18% of elderly metastatic breast cancer patients.

What factors increase breast cancer risk postmenopause?

The following may increase the risk of postmenopausal breast cancer:

• Certain genetic abnormalities such as BRCA1 or BRCA 2 mutations, Cowden syndrome, Peutz-Jeghers syndrome
• Family history of breast cancer
• Personal history of breast cancer or certain benign breast conditions
• History of radiation therapy to the chest
• Use of hormonal medications as contraceptives or hormone replacement therapy
• Early menarche (before age 12)
• Never having been pregnant or having a first child after age 30
• Dense breast tissue
• Obesity
• Sedentary lifestyle
• Excessive alcohol consumption

Tips for managing postmenopausal breast cancer

Menopause and breast cancer may take a dual toll on your mental and physical health. The following tips can help you cope with these conditions:

• Strictly comply with your treatment recommendations
• Discuss your concerns with your doctor
• Eat a healthy diet rich in fruits and vegetables, lean protein, and whole grains.
• Stay physically active and engage in regular exercise
• Stay hydrated
• Avoid alcohol
• Quit smoking
• Get adequate sleep
• Manage stress