PR-Positive Breast Cancer

Medically Reviewed by Melinda Ratini, MS, DO on May 07, 2024
4 min read

When you have breast cancer, your doctor may remove some or all of the cancer tissue through a biopsy or surgery. Then, they’ll order tests of these cells to help them learn more about the cancer. One test looks for hormone receptors, which are proteins found in and on cells, including cancer cells. Hormones attach to these receptors and help the cells grow.

Progesterone is a natural hormone made in our bodies. In females, it plays a role in puberty, menstrual cycles, and pregnancy. Some breast cancer cells have progesterone receptors on them. This is called progesterone-receptor positive, or PR positive (PR+), breast cancer. Progesterone attaches to these cancer cells to help them grow; treatments that target progesterone can halt this growth.

The hormone estrogen works much the same way. Cancers with estrogen receptors are called estrogen-receptor, or ER positive (ER+).

If your cancer cells are PR-positive, ER-positive, or both, it’s called hormone-receptor (HR) positive, or HR+ breast cancer. About 7 out of 10 breast cancers are hormone-receptor positive. You can get HR-positive breast cancer at any age. But it’s more common in women who have already gone through menopause.

Overall, the risk factors for HR-positive breast cancer are the same as those for any type of breast cancer. They include:

  • Being female
  • Getting older
  • Having certain changes in your breast cells in the past, such as LCIS (lobular carcinoma in situ) or an overgrowth of abnormal breast cells (called proliferative changes with atypia)
  • Having a family history of breast cancer.
  • Starting your periods before age 12
  • First giving birth after about age 35
  • Never having a full-term pregnancy
  • Starting menopause after age 55
  • Using hormone replacement therapy after menopause

Many women don’t have any symptoms of breast cancer when they get a diagnosis. Instead, doctors find it during a routine mammogram screening.

HR-positive breast cancer has the same symptoms as other types of breast cancer. Some of the more common symptoms include:

  • A new lump in your breast
  • Swelling of part or all of your breast
  • Pain in your breast or nipple
  • Changes in the skin over your breast (it may dimple, look like an orange peel, thicken, or become dry, red, and flaky)
  • Nipple changes (they may turn inward or have a discharge)
  • Swollen lymph nodes, which may feel like lumps under your arm or near your collarbone

Your doctor will consider the hormone status of your breast cancer when they plan your treatment. One of the main treatments for PR-positive breast cancer is hormone therapy, which keeps HR-positive cancer cells from using hormones to grow.

Hormone therapy works by removing hormones from your body or blocking their ability to attach to the receptors on your cells. There are two main ways you may get hormone therapy:

  • Surgery to take out your ovaries so your body doesn’t make any more breast-cancer-related hormones
  • Hormone therapy pills or shots, which keep your body from making female hormones or block the receptors so hormones can’t attach to cancer cells

The type you get will depend in part on whether you’ve gone through menopause yet.

Hormone therapy can be part of treatment for any stage of HR-positive breast cancer. You may get it along with other treatments, such as surgery or chemotherapy, depending on the stage of your cancer.

If your cancer can be removed with surgery, is early stage (ductal carcinoma in situ, or DCIS), or is limited to the place it first started in your breast (localized), you might get hormone therapy:

  • Before surgery to help shrink the tumor
  • After surgery, with or without chemotherapy, to decrease the chance that the cancer will come back

If you have inflammatory breast cancer or the tumor has spread from where it first started (locally advanced or invasive), you might get hormone therapy after surgery.

You might get hormone therapy if your breast cancer comes back after treatment. If your cancer has spread to other parts of your body (metastatic breast cancer), hormone therapy is usually part of your main treatment.

Along with hormone therapy, you may also get one or more of these treatments for PR-positive breast cancer:

  • Surgery, such as a lumpectomy or mastectomy, to remove cancer cells
  • Chemotherapy
  • Radiation
  • Targeted therapy drugs, which target proteins on breast cancer cells that help them grow. These medications can help hormone therapy work better.

Hormone receptor-positive types of breast cancer grow more slowly than those that are hormone-receptor negative. They also give you an advantage in treatment, since progesterone blockers can halt the growth of your cancer cells. Still, the sooner you’re diagnosed, the better your prognosis will be.

Hormone therapy can lower your estrogen levels or block the receptors to keep HR-positive cancer from growing and spreading. But sometimes these cancers come back, even many years after treatment. Because of this, you may get hormone therapy for up to 10 years.

Talk with your doctor about your hormone receptor status and what it means for you.