Breast Cancer Awareness Month: Is there a link between breast cancer and periods?

A lump and a change in the size or shape of your breast are not the only ways breast cancer can impact you. This type of cancer, which is common among women, and the treatment may affect your menstrual health. While breast cancer itself may not affect your period, the treatment options may lead to amenorrhea or the absence of menstruation. In fact, your menstrual cycle may also have a connection with breast cancer risk. October is the Breast Cancer Awareness Month, making it the perfect time to explore the connection between breast cancer and periods.

What is breast cancer?

Breast cancer is a malignant (cancerous) tumour that originates in the cells of the breast tissue. It starts in the breast, and sometimes can spread to another part to the body, according to the UK’s National Health Service. In 2022, breast cancer was the most common type of cancer in women in 157 countries, and it caused 6,70, 000 deaths globally, as per the World Health Organization. It occurs in women at any age after puberty, but the chances increase in later life. Some of the risk factors of this type of cancer are –

• Increasing age
• Obesity
• Harmful use of alcohol
• Family history of breast cancer
• A history of exposure to radiation

What are the symptoms of breast cancer?

Symptoms of breast cancer include:

• A breast lump, which may feel hard, irregular in shape, and a bit different from the rest of the breast tissue
• Swelling or shrinking of just one breast
• Nipple changes like inversion or discharge
• Breast skin changes like dimpling or redness or appearing more like an orange peel
• Breast or nipple pain

Some women may not experience noticeable symptoms of breast cancer, which is why regular breast exams and mammograms are essential for early detection.

How does breast cancer affect periods?

Breast cancer may not have a direct impact on a woman’s menstrual cycle. But the treatments for breast cancer can significantly influence hormonal balance, potentially impacting periods, says obstetrician and gynaecologist Dr Chetna Jain.

Here’s how breast cancer treatments can affect menstruation:

1. Chemotherapy

Chemotherapy, one of the most common treatments for this type of cancer, uses strong drugs to attack rapidly dividing cells, including cancer cells. However, these drugs can also affect the ovaries, leading to temporary amenorrhea. During a 2020 study published in the Breast Cancer Research and Treatment journal, 76 percent of participants developed chemotherapy-related amenorrhea. Out of them only 40 percent of the participants resumed menstruation following treatment.

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“In some women, particularly those closer to natural menopause (usually in their 40s or older), chemotherapy can cause permanent ovarian failure, leading to early menopause and the permanent cessation of periods,” says Dr Jain. For some women, chemotherapy may also cause periods to become irregular, less frequent, or heavier than usual.

2. Hormone therapy

Hormone therapies, such as Tamoxifen or Aromatase Inhibitors, are often used in women with hormone receptor-positive breast cancer to block estrogen or reduce its levels in the body. These therapies can cause irregular periods, changes in flow, or even the complete cessation of periods in some women, especially if they are approaching menopause.

3. Ovarian suppression

In some cases, breast cancer treatment may involve ovarian suppression so that the levels of estrogen get reduced in the body. “Medications such as Goserelin (Zoladex) can be used to temporarily “shut down” the ovaries, stopping estrogen production,” says the expert. This can lead to a temporary stop in periods, mimicking menopause.

4. Radiation therapy

Most women exposed to radiation therapy resume menstruation within two years, but once resumed, older women may have irregular periods, as per research published in the Fertility and Sterility journal in 2017. Radiation therapy targeting the breast does not usually affect periods, but radiation to other areas like the pelvis, can damage the ovaries and lead to menstrual changes.

Can menstrual history increase breast cancer risk?

“Yes, a woman’s menstrual history is one of the factors of breast cancer risk,” says the expert. During a 2016 study published in the Frontiers in Oncology, a strong association was found between the time of onset and cessation of menstrual cycling and increased breast cancer risk. Researchers found that for each year, the younger a girl starts menstruating, there is a 5 percent rise in the risk of breast cancer later in life.

“The breast cancer risk is related to how long a woman has been exposed to estrogen, which stimulates growth of breast cells. Over time, it can influence the development of cancerous cells,” says Dr Jain. So, women who have their first period before they turn 12, have more chances of developing breast cancer due to prolonged exposure to estrogen. “Older women who have menopause after age 55 are also at higher risk due to the extended time of estrogen exposure,” shares the exert.

What to do if you lose your period during breast cancer treatment?

Losing your period during breast cancer treatment can be distressing, but it is a common side effect. Here’s what to do:

• Discuss your concerns with your doctor, who can explain whether your amenorrhea is temporary or permanent based on factors like your treatment regimen, and age.
• If you are concerned about fertility, talk to a fertility specialist before starting breast cancer treatment. Options like egg or embryo freezing can be considered to preserve fertility before chemotherapy or hormone therapy.
• If periods do not return, early menopause can lead to decreased bone density. Your doctor may tell you to take calcium and vitamin D supplements to support bone health.
• Maintaining a healthy lifestyle, including a balanced diet, regular physical activity, and managing stress, can help deal with the side effects of period loss and treatment.

The connection between breast cancer and periods may not be direct. But you may experience the loss of periods during the breast cancer treatment, and find it distressing. But it is important to focus on the overall goal of the treatment.