Oestrogen Receptor Positive Breast Cancer

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Oestrogen receptor positive breast cancer is the most common breast cancer subtype. Oestrogen signalling drives tumour growth, and treatment focuses on blocking that signal with hormone therapy such as tamoxifen.

Nolvadex

Tamoxifen

10/20mg

Nolvadex is a oncology medication containing Tamoxifen, available as 10/20mg tablets.

from $0.32 / tablet View

Key facts

  • Oestrogen receptor positive (ER-positive) breast cancer is the most common breast cancer subtype, accounting for roughly two-thirds of all cases.
  • The cancer cells carry receptors that bind oestrogen, and that binding signals them to grow.
  • Treatment focuses on cutting off the oestrogen supply or blocking the receptor directly, most often with tamoxifen.
  • A new lump, nipple change, unexplained bone pain, or side effects that persist during treatment should be reviewed by a doctor promptly.

What ER-positive means

Breast cancer cells are tested for hormone receptors at diagnosis, alongside markers such as HER2 status, since the combination shapes the whole treatment plan. In ER-positive tumours, the cells carry receptors that bind circulating oestrogen, and that binding switches on the genes that drive the cells to grow and divide. Because the tumour depends on this signal, interrupting it is often more effective, and better tolerated, than chemotherapy alone, which is why hormone therapy is the backbone of treatment for this subtype rather than an add-on.

How hormone therapy targets it

Tamoxifen is the most established treatment for ER-positive disease. It binds the oestrogen receptor without activating it, starving the tumour of the growth signal it depends on, and has decades of evidence behind it in both early and advanced disease. Aromatase inhibitors such as anastrozole, letrozole and exemestane lower oestrogen production after menopause and are commonly used as an alternative or a follow-on treatment. Hormone therapy is usually continued for several years, since stopping early raises the chance of recurrence. Broader support during and after treatment falls under oncology care.

When to see a doctor

Persistent side effects, a new lump, a nipple change or unexplained bone pain should be reviewed by an oncologist promptly, and hormone therapy should not be stopped without medical advice even when side effects are troublesome.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.