HRT Won’t Give You Breast Cancer — The Real Numbers

The claim that hormone replacement therapy causes breast cancer has kept South African women in unnecessary pain and danger for over 20 years. The evidence says it’s time to read the actual numbers.

Every GP in South Africa has heard it. A woman in her early 50s, drenched in sweat every night, not sleeping, her joints aching and her mood unrecognisable to herself, sits across the desk and says: “But I don’t want HRT — doesn’t it cause breast cancer?”

The short answer is: it’s far more complicated than that, and the absolute risk is small enough that many women are suffering preventable symptoms because of a study that was badly reported and widely misunderstood. Here is what the evidence actually says.

Where the fear came from: the 2002 Women’s Health Initiative study

The panic has a precise origin date: 9 July 2002, when the United States Women’s Health Initiative trial published results linking combined hormone replacement therapy (oestrogen plus progestogen) to an increased risk of breast cancer. The media ran with it globally. Prescriptions collapsed. South African doctors, like their counterparts everywhere, became reluctant to prescribe.

Here is what the headlines missed.

The mean age of Women’s Health Initiative participants was 63.2 years — more than a decade past natural menopause. The trial was designed primarily to study cardiovascular disease prevention in older women, not to assess whether hormone replacement therapy was safe and effective for newly menopausal women managing symptoms.

The study was never meant to serve as the final word on hormone replacement therapy, or even examine whether it was safe and effective for menopause symptoms like hot flushes, night sweats, insomnia, or brain fog.

The risk was also reported in a way that inflated its apparent size.

The media focused their reporting on relative risk, citing that women who use hormone replacement therapy have a 26% increased risk of breast cancer developing. The actual risk should have been reported in terms of absolute risk, with a modest increase in risk of 4 additional cases of breast cancer per 1,000 women taking hormone replacement therapy over 5 years. The damage, however, was done.

What the evidence actually says: putting 3 extra cases in perspective

For women of average weight, five years of menopausal hormone therapy starting at age 50 years would increase breast cancer incidence from age 50 to 69 years by about one additional case in every 50 users of oestrogen plus daily progestogen, one in every 70 users of oestrogen plus intermittent progestogen, and one in every 200 users of oestrogen-only therapy.

To translate that into a figure you can actually calibrate against: combined oestrogen-progestogen hormone replacement therapy produces roughly 3 extra cases of breast cancer per 1,000 women over 5 years of use. Put another way, 997 women out of every 1,000 taking combined hormone replacement therapy for 5 years will not develop breast cancer as a result of the treatment.Compare that to other breast cancer risk factors most South African women don’t think twice about.

The risk of developing breast cancer increases by approximately 10% for each additional daily standard unit of alcohol consumed — meaning a daily glass of wine carries a similar order of risk to combined hormone replacement therapy, without anyone issuing a global health panic about it.

The South African Menopause Society’s 2014 consensus position statement made exactly this point: “The absolute risk of breast cancer attributable to hormone therapy is low and falls into the same risk category as several preventable risk factors that are associated with a similar low relative risk for developing breast cancer. Examples of these are obesity, nulliparity and never having breastfed.”

Critically,oestrogen-only hormone replacement therapy has little impact on breast cancer risk in naturally or surgically menopausal women. In particular, the long-term follow-up of the Women’s Health Initiative randomised trials suggests a benefit of oestrogen alone. Women who have had a hysterectomy and take oestrogen-only therapy face no meaningful increase in breast cancer risk at all.

The nuanced truth: timing, formulation, and the individual woman

Not all hormone replacement therapy is the same, and not all women are the same. Current evidence from the South African Society of Obstetricians and Gynaecologists’ 2023 clinical guideline, as well as international guidance, converges on a few key principles.

Timing matters.

Initiation of therapy during the “therapeutic window of opportunity” — between 50 and 60 years of age or within 10 years of onset of menopause — results in a much better benefit-to-risk profile than initiation in older patients.

The “timing hypothesis” proposes that hormone replacement therapy initiated within 10 years of menopause onset or before age 60 may confer cardiovascular benefit, whereas later initiation may increase cardiovascular risk.

Formulation matters.

Contemporary knowledge has revealed that not all progestins are the same, and that natural progesterone and tibolone do not report a significant increase in the relative risk of breast cancer.

Synthetic progestins — particularly medroxyprogesterone acetate, which was used in the Women’s Health Initiative — carry a higher risk than micronised progesterone. Transdermal oestradiol carries less clotting risk than oral preparations.

Individual context matters. South African women face a disease burden that requires honest, individualised conversations.

Breast cancer is the most common cancer in South African women of all races, with a lifetime risk of 1 in 27, according to the 2023 National Cancer Registry.

That context is real — but so is the fact that untreated menopause carries its own risks, including accelerated bone loss and cardiovascular disease.

Hormone replacement therapy reduces vasomotor symptoms (hot flushes and night sweats) by up to 90% and is prescribed as first-line treatment to prevent and treat osteoporosis. The South African General Practitioner journal noted in 2023 that hormone replacement therapy is “controversial, misunderstood and as a result often underutilised by clinicians” in South Africa — a direct consequence of the 2002 panic that was never adequately corrected in public discourse.

No local South African data on hormone replacement therapy uptake rates currently exists; the South African Menopause Society and South African Society of Obstetricians and Gynaecologists are the primary local authorities on this topic.

Getting access: what it costs and who provides it

Private sector

A first consultation with a private general practitioner to discuss menopause and hormone replacement therapy costs roughly R700–R900.

A gynaecologist consultation in South Africa runs around R700 at published private practice rates.

If you need further investigation, a screening mammogram runs from about R1,200. Monthly hormone replacement therapy prescriptions vary by formulation, but oral or transdermal options from a public or private pharmacy generally cost R100–R350 per month for generic preparations.

A routine annual gynaecological check is a day-to-day expense on almost every medical aid plan, which means it comes off savings or out-of-hospital benefit. Once that pot is empty, usually somewhere in the second half of the year, the full consultation cost is yours.

Gap cover can help, but check your option’s rules before you book.

Menopause management does not fall under Prescribed Minimum Benefits as a standalone condition, which means most medical aids will fund initial consultations at scheme rates but will not necessarily cover ongoing prescription costs in full. Speak to your scheme’s case management line — some options on Discovery, Bonitas, and Momentum cover chronic hormone therapy under a wellness benefit.

Public sector

Women in the public sector can raise menopause-related symptoms with a general practitioner at a community health centre. Referral to a district or regional hospital’s gynaecology outpatient clinic is the route for specialist assessment. Hormone replacement therapy medications do appear on the Essential Medicines List, meaning oestrogen preparations can be dispensed at public sector facilities, though availability varies by province and is subject to the same stock-out pressures that affect the broader system. Load-shedding can disrupt after-hours clinic access — if your nearest clinic runs reduced hours, check the fixed schedule in advance rather than assuming normal operating hours.

What to do instead of avoiding hormone replacement therapy altogether

The goal is not to persuade every woman to take hormone replacement therapy. The goal is to make sure no woman is refusing it because of a misread 2002 statistic.

Find a doctor who uses current evidence. The South African Society of Obstetricians and Gynaecologists 2023 clinical guideline and the South African Menopause Society’s position statements are the local benchmarks. If your doctor cites a blanket refusal to prescribe based on the Women’s Health Initiative, ask them about the timing hypothesis and the absolute risk figures.

Know your own risk profile. A personal or family history of breast cancer, clotting disorders, or unexplained vaginal bleeding all require careful assessment before starting hormone replacement therapy. These are conversations to have with a doctor — not reasons to avoid the conversation altogether.

Consider the full picture. Untreated severe menopausal symptoms affect sleep, concentration, mood, relationships, and work. Accelerated bone loss after menopause raises hip fracture risk — a fracture that, in older South African women with limited access to rehabilitation, carries serious long-term consequences. These risks are real and they belong in the calculation too.

When to see a doctor Book a consultation if you are experiencing moderate to severe hot flushes, night sweats, sleep disruption, vaginal dryness, or mood changes that are affecting your daily function. If you have a personal history of breast cancer, clotting disorders, liver disease, or undiagnosed vaginal bleeding, tell your doctor before any hormone therapy is considered — these require specialist assessment, not avoidance of care. Your nearest public health clinic can refer you; private general practitioners and gynaecologists can assess you directly.

Bottom line

• The 2002 Women’s Health Initiative study was misapplied. Its participants averaged 63 years old — not newly menopausal women — and its findings were reported as relative risk rather than absolute risk.
• The absolute breast cancer risk from combined hormone replacement therapy is roughly 3 extra cases per 1,000 women over 5 years — a figure comparable to the risk from daily alcohol use or being obese.
• Oestrogen-only hormone replacement therapy carries little to no increased breast cancer risk and may reduce it with long-term use.
• Start within 10 years of menopause. The benefit-to-risk profile is markedly better when hormone replacement therapy is initiated in the therapeutic window of opportunity.
• The South African Society of Obstetricians and Gynaecologists and the South African Menopause Society both support individualised prescribing — not blanket avoidance.
• Talk to a doctor using current evidence, not a 2002 headline.