Hormone receptor-positive breast cancer: what it means and how it is treated

Breast cells contain special proteins called hormone receptors, which receive messages from hormones in the body and tell the cells what to do. The receptors found in breast cells are oestrogen receptors and progesterone receptors. When breast cancer cells carry oestrogen receptors the cancer is called oestrogen receptor positive, or ER-positive, and the cells can use oestrogen to help them grow. When they carry progesterone receptors it is called progesterone receptor positive, or PR-positive.

Breast Cancer Now notes that most PR-positive breast cancers are also ER-positive and that very few cancers are PR-positive only.

All invasive breast cancers are tested for oestrogen receptors, using tissue taken in a biopsy or after surgery. Invasive breast cancers should also be tested for progesterone receptors. The result is one of the pieces of information your team uses when deciding which treatments to offer.

The NHS says the treatment you have depends on the size and type of the breast cancer, where it is, whether it has spread to other parts of the body and your general health. A specialist care team will explain the treatments, their benefits and side effects and create a treatment plan with you.

Hormone therapies are drugs that block or stop the effect of oestrogen and progesterone on breast cancer cells, or reduce the amount of oestrogen in the body. Breast Cancer Now lists the most common drugs as tamoxifen, the aromatase inhibitors (anastrozole, exemestane and letrozole), goserelin, leuprorelin and fulvestrant. Aromatase inhibitors are normally used in women who have been through the menopause, and leuprorelin is used in women who have not.

Timing varies. In primary breast cancer hormone therapy is usually started after surgery as an adjuvant treatment to reduce the risk of the cancer coming back and possibly of a new cancer developing. If chemotherapy follows surgery, hormone therapy usually starts when chemotherapy finishes. Some women who have been through the menopause are prescribed it before surgery to shrink the cancer or if surgery is delayed, and occasionally it is given when surgery is not safe. It can also treat cancer that has come back or spread.

Breast Cancer Now says hormone therapy can also be used to reduce the risk of breast cancer in women at much higher than average risk, with drugs such as tamoxifen, anastrozole and raloxifene, usually taken for 5 years.

The most common side effects of hormone therapy are menopausal symptoms such as hot flushes, night sweats, vaginal dryness, reduced sex drive, mood changes, and joint pain and stiffness, which Breast Cancer Now says are often more intense than when the menopause happens naturally. Other common effects include effects on the bones, tiredness, headaches, feeling sick and diarrhoea.

Aching in the joints and muscles is described as often mild and temporary, though for some people more severe and longer lasting. It is often in the hands, wrists and knees and can be worse first thing in the morning. If side effects are affecting quality of life or putting you off taking treatment, the advice is to talk to the treatment team, who may suggest a short break or a switch to a different drug.

Your team will tell you when to stop. You will not need to stop gradually and stopping will not cause side effects. Breast Cancer Now says it will continue to reduce the risk of the cancer coming back for many years after you finish, known as the carryover effect, which may last for 5 years or longer.

The NHS says the main treatment for breast cancer is usually surgery, which may remove only the area of the breast with cancer, the whole breast (mastectomy) or lymph nodes in the armpit, with reconstruction an option after mastectomy. Radiotherapy may be given after surgery to lower the chance of the cancer coming back. Chemotherapy may be given before surgery to shrink the cancer or after surgery if the cancer has spread to lymph nodes or is growing quickly.

Targeted medicines and immunotherapy may be used in some cancers. If the cancer has spread, treatment may focus on managing symptoms and slowing growth and the NHS notes this can help many people live a normal life for a number of years. You will have regular check-ups during and after treatment and the NHS encourages contacting your specialists if you have symptoms or side effects you are worried about rather than waiting for the next appointment.

On the NHS, breast cancer care is coordinated by a specialist multidisciplinary team, and hormone therapy is prescribed by your specialist team. Some people choose to see a private oncologist or breast surgeon for speed or a second opinion. The tests and treatments are the same drugs, and a private team will usually need your pathology report, so ask for copies of your receptor results.