Vaginal oestrogen an option for breast cancer survivors

5 minute read

Several alternatives are available for treating genitourinary symptoms, even for women who’ve had hormone receptor-positive breast cancer.

Vaginal oestrogen should still be considered for the majority of women who’ve had breast cancer, Australian experts say.

Women who’ve had breast cancer oestrogen deprivation treatment are likely to experience genitourinary menopausal side effects that are chronic and progressive. But clinicians have had concerns about treating these symptoms with oestrogen in case it increased the risk of tumour recurrence.

Now a GP, a medical oncologist, an endocrinologist and a breast surgeon have compiled evidence to guide GPs whose patients fall into the 75% of breast cancer survivors experiencing vaginal dryness, itching, burning, pain, irritation, dysuria, urinary urgency, nocturia, incontinence, recurrent UTIs and dyspareunia. 

The group came together after a debate at a conference last year presenting opposite sides of the safety debate.

Author Dr Belinda Kiely, a medical oncologist and senior research fellow at the NHMRC Clinical Trials Centre, was concerned that those who saw the debate would leave thinking they should never prescribe vaginal oestrogen to breast cancer survivors, leaving many patients without the treatment that could change their quality of life.

“Women with breast cancer who are bothered by genitourinary symptoms face a difficult decision when considering vaginal oestrogen therapy. General practitioners can assist by making an assessment including a thorough history and offering an examination, ensuring that non-hormonal measures are in place, helping to quantify the individual woman’s risk of breast cancer recurrence and discussing the known evidence around the use of vaginal oestrogens,” the authors wrote.

The evidence showed that vaginal oestrogen was certainly not the only effective treatment for genitourinary symptoms. In fact, non-hormonal treatments are recommended as the first go-to and can be enough for many women, Dr Kiely told TMR. Regular vaginal moisturiser was shown to be as effective as 10mcg oestradiol tablets for relieving many of the worst symptoms.

But for breast cancer survivors with recurrent symptoms that don’t respond to non-hormonal treatments, vaginal oestrogen could be considered.

“The existing evidence is reassuring for women on tamoxifen or no adjuvant endocrine therapy who are considering using vaginal oestrogen. The situation for women using aromatase inhibitors is less certain and further studies are needed to assess safety,” the authors wrote.

The guidance, published in the AJGP this month, was that vaginal oestrogen can be prescribed in the context of:

  • hormone receptor-negative breast cancer
  • hormone receptor-positive breast cancer in women currently taking tamoxifen
  • hormone receptor-positive breast cancer in premenopausal women currently taking gonadotropin-releasing hormone agonist with tamoxifen (stopping the former in consultation with patient and oncology team “might also improve symptoms”)
  • hormone receptor-positive breast cancer where adjuvant endocrine therapy is complete or stopped (usually 5-10 years post diagnosis)

For women taking aromatase inhibitors rather than tamoxifen, the patient’s decision to use vaginal oestrogen required weighing up specific risks and benefits. Tamoxifen could block any systemically absorbed oestrogen, but aromatase inhibitors did not. Tamoxifen also had fewer genitourinary side effects. However, aromatase inhibitors had recurrence and survival advantages.

The authors recommended that vaginal oestrogen only be prescribed in consultation with an oncologist where a patient:

  • has hormone receptor-positive breast cancer and is currently taking aromatase inhibitors. Consider switching to tamoxifen if possible. If not, and the patient, in consultation with oncologist, decides the risk is acceptable, trial vaginal oestrogen for 12 weeks and continue if improvement is significant.
  • has hormone receptor-positive breast cancer, is pre-menopausal and is currently taking gonadotropin-releasing hormone agonist with aromatase inhibitor. Consider switching to tamoxifen + GnRH if possible and then stopping GnRH agonist if there’s no improvement. If not possible, and the patient, in consultation with oncologist, decides the risk is acceptable, trial vaginal oestrogen for 12 weeks and continue if improvement is significant.

Author Dr Karen Magraith, a Hobart GP and past president of the Australasian Menopause Society, told TMR that in the latter cases a team approach and shared decision making would ensure the patient did not miss out on the best available options for them.

Usually this meant consulting with the patient’s existing or past cancer specialist, and oncologist Dr Kiely said she frequently consulted with her patients’ GPs, but she also received referrals for women whose original oncologist was not available.

In Australia, there are two types of low-dose vaginal oestrogen products available on the PBS: oestradiol (Vagifem Low pessary and Estro-Pess), and oestriol (Ovestin cream 0.1% and Ovestin Ovula pessary). The research shows a “theoretical” advantage for oestriol over oestradiol for women with hormone receptor-positive breast cancer, but there is no clinical data to show one being better than the other.

“Some women find the tablets easier to use, whereas others prefer the cream because it can be targeted to areas of most concern. Insertion into the lower third of the vagina is preferable to maximise response and minimise absorption. Treatment is usually commenced with daily use for 14 days, then twice weekly,” the authors wrote.

Patients might also source their own products from overseas, Dr Magraith noted, including dehydroepiandrosterone vaginal pessaries (also known as DHEA and prasterone) are approved by the TGA but not yet available here. Another, oral tablet Ospemifene, is not yet TGA-approved. Both are FDA-approved and there is evidence for efficacy but not yet safety in breast cancer survivors.  

The authors found no evidence to support measuring serum oestrogen concentrations to assess systemic absorption of vaginal oestrogens.  

Genitourinary symptoms could appear early during treatment or many years down the track. Dr Magraith said many women were coming forward to discuss these symptoms and what could be done about them but others were not aware that treatment was available. It was a subject worth raising in a consultation, she said. 

AJGP 2023, online 13 May

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