Hormone Therapy and Breast Cancer Recurrence

A woman receives a breast cancer exam from a healthcare professionalShare on Pinterest
Women treated for breast cancer can experience a number of side effects after treatment. Anchiy/Getty Images
  • Hormone replacement therapy is sometimes recommended for women after breast cancer treatment.
  • In the past, some oncologists have expressed concerns that this type of menopausal therapy may raise the risk of breast cancer recurrence.
  • In a new study, researchers said they found no link between breast cancer recurrence and hormone replacement therapy.
  • One expert said this is welcome news for breast cancer survivors but cautioned women who are taking aromatase inhibitors about using hormone replacement therapy.

Night sweats, fatigue, dental issues, osteoporosis, heart problems, hot flashes, vaginal dryness, and urinary tract infections.

These are just some of the side effects that people who are treated with hormone therapy for breast cancer have endured. Examples of hormone therapy include drugs such as tamoxifen and aromatase inhibitors.

Many breast cancer survivors take these drugs after breast cancer surgery to help prevent the cancer from recurring. Treatment can last up to five years but may be needed for longer, according to the American Cancer Society.

These sometimes serious symptoms of breast cancer hormone therapy can negatively affect quality of life and even prompt some people to discontinue this cancer treatment.

Over the years, vaginal estrogen therapy and menopausal hormone therapy have been used to help alleviate some of these symptoms.

However, the safety of using systemic and vaginal estrogen in breast cancer survivors, particularly those with estrogen receptor-positive disease, haven’t been thoroughly studied.

A new paper in the Journal of the National Cancer Institute published by Oxford University Press reports that menopausal hormone therapy for breast cancer survivors is not associated with breast cancer recurrence.

According to the authors of the recent study, some oncologists have warned cancer survivors against using menopausal hormone therapy as earlier clinical trials have reported an increased risk of breast cancer recurrence.

Although studies since then have not shown an increase in recurrence, such studies had serious limitations, including small sample sizes and short follow-up periods.

Dr. Søren Cold, an oncologist at Odense University Hospital in Denmark, decided to take a closer look.

In his new paper, Cold studied the association between hormone replacement therapy with the risk of breast cancer recurrence and mortality in a large cohort of Danish postmenopausal women treated with hormone therapy for early-stage estrogen receptor-positive breast cancer.

The women were diagnosed between 1997 and 2004 with early-stage breast cancer and received no treatment or five years of hormone therapy for their breast cancer, Soren told Healthline.

Among 8,461 women who had not received vaginal estrogen therapy or menopausal hormone therapy before a breast cancer diagnosis, 1,957 used vaginal estrogen therapy and 133 used menopausal hormone therapy after diagnosis to help with the side effects of breast cancer hormone therapy.

The researchers said that overall they found no increase in the risk of recurrence or mortality for those who received either vaginal estrogen therapy or menopausal hormone therapy.

However, they did see an increased risk of recurrence in people using vaginal estrogen therapy while taking aromatase inhibitors.

Dr. Elizabeth Cathcart-Rake, an oncologist at the Mayo Clinic in Minnesota, was asked to write an editorial about the study.

“Essentially, it appears that breast cancer survivors on tamoxifen may consider vaginal estrogen therapy as it does not appear that this significantly increases their risk for breast cancer recurrence,” she told Healthline.

“I agree that this is good news for many patients suffering from severe genitourinary symptoms of menopause,” she added.

However, Cathcart-Rake noted that there are still caveats for some people with breast cancer.

“I would be cautious with considering vaginal estrogen for women on aromatase inhibitors,” she said.

This subgroup, Cathcart-Rake said, did appear to have a higher risk for recurrence, although mortality wasn’t significantly different.

She also expressed caution for women considering oral menopausal hormonal therapy.

“There just weren’t many women in this cohort in this study and we have prior data showing increased risk for recurrence with the combination,” she said.

Cathcart-Rake said this study is particularly interesting and helpful “because it includes such a large cohort of patients in which we have records of their medications and refills, as well as data on recurrence, due to the health system.”

“This large cohort study helps to inform the nuanced discussions between clinicians and breast cancer survivors about the safety of vaginal estrogen therapy,” she added.

Cathcart-Rake said the results of the study suggest that breast cancer survivors on tamoxifen with severe genitourinary symptoms can take vaginal estrogen therapy without experiencing an increase in their risk for breast cancer recurrence.

But, she said, “Caution is still advised when considering vaginal estrogen for breast cancer survivors on aromatase inhibitors or when considering menopausal hormonal therapy.”

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