Luminal A Breast Cancer

What is luminal A breast cancer?

Luminal A breast cancer is a subtype of hormone receptor-positive (HR+) breast cancer. HR+ breast cancer cells have proteins (receptors) inside them that encourage cancer growth when estrogen or progesterone attach to them. “Luminal” refers to cells in your breast duct lining, where most breast cancers start.

Characteristics

Luminal A cells usually have low levels of Ki-67 — a protein found in rapidly dividing cells. Because of this, luminal A breast cancers usually grow slower than luminal B and other subtypes of breast cancer.

Luminal A cancer cells are:

• Positive for estrogen. This means they contain high estrogen receptor (ER) proteins that may help cancer cells grow.
• Positive for progesterone. They have high progesterone receptor (PR) proteins that may encourage cancer growth.
• HER2-negative (HER2-). Luminal A cells don’t usually contain a protein called human epidermal growth factor receptor 2 (HER2). (Other breast cancer types, like luminal B, may be HER2+ or HER2-.)
• Low in Ki-67. Ki-67 is a protein found only in rapidly dividing cells. That’s why luminal A breast cancers typically grow slower than luminal B breast cancers.
• Lower grade. Luminal A cells are usually less aggressive and less likely to recur (come back) than luminal B cancers.

All this information can be confusing. But it’s important. It represents a molecular-level analysis of the cancer cells in your breast. It can help your healthcare provider design a personalized plan and predict how you’ll respond to various treatments.

How common is luminal A breast cancer?

Luminal A makes up about 50% to 60% of all breast cancer cases. It’s the most common molecular subtype of breast cancer.

What are the symptoms of luminal A breast cancer?

Luminal A breast cancer symptoms may include:

• A lump in your breast.
• Breast pain.
• Nipple discharge.
• Thickened or dimpling skin.
• Swelling of your breast or in your armpit.

However, you might not have any symptoms. This is because healthcare providers often detect breast cancer during routine cancer screenings, before symptoms develop.

What causes luminal A breast cancer?

Luminal A breast cancer occurs when healthy cells in your breast change and grow uncontrollably. Experts aren’t exactly sure why this happens. But they’ve identified factors that may increase your chances of developing breast cancer.

Risk factors include:

• A family history of breast or ovarian cancer.
• Being over the age of 50.
• Dense breast tissue.
• Drinking alcohol.
• Prior radiation treatment to your chest or breasts.
• Prolonged exposure to hormones like estrogen or progesterone. This can happen because of things like early menarche (your first period), late menopause or HRT.

How is luminal A breast cancer diagnosed?

Healthcare providers diagnose most breast cancers with screening mammograms. Your provider will order additional imaging tests if your mammogram results look suspicious. These tests might include:

• Diagnostic mammogram.
• MRI.
• Ultrasound.

They’ll likely do a breast biopsy, too. During this procedure, they’ll remove a small sample of your breast tissue and send it to a pathologist for further testing. If the pathologist finds cancer cells, they’ll run more tests to determine whether the cells are Luminal A.

Knowing which cancer subtype you have can help your oncologist determine which treatments will be most effective. It can also tell them whether the cancer is likely to return after treatment.

How is luminal A breast cancer treated?

Luminal A breast cancer treatment options include:

• Hormone-blocker therapy. Because luminal A breast cancer is HR+, it usually responds well to hormone blocker therapy. This might include tamoxifen aromatase inhibitors or ovarian suppression therapy.
• Surgery. This includes lumpectomy or mastectomy to remove cancer cells from your breast.
• Radiation therapy. Your oncologist may recommend radiation after surgery to kill any remaining cancer cells in the area.
• Chemotherapy. Chemotherapy drugs usually work best for fast-growing tumors. But some people with luminal A breast cancer may benefit from chemotherapy. Your oncologist can tell you if this is an option for you.

You may need a combination of these treatments. Your oncologist will tailor your care plan based on your biopsy results.

How can I reduce my risk for luminal A breast cancer?

Some risk factors are unavoidable, like having a family history of breast cancer. But doing the following may help reduce your overall cancer risk:

• Avoid smoking and vaping.
• Eat lots of fruits, veggies and whole grains.
• Increase your physical activity.
• Limit alcohol intake.
• Maintain a weight that’s healthy for you.

What’s the outlook for people with luminal A breast cancer?

Luminal A breast cancer has the best outlook of all the molecular subtypes. Still, your prognosis depends on the tumor’s size, how fast it grows and whether it has spread at the time of your diagnosis. The sooner you start treatment, the better your outlook will be.

Luminal A breast cancer can go into remission with treatment, and in most early stage cases, it’s curable.

Luminal A breast cancer survival rates

The five-year survival rate for luminal A breast cancer is 95%. That means that 95% of people with this type of breast cancer are still alive five years after their diagnosis.

Survival rates are only estimates based on past outcomes of other people with luminal A breast cancer. They can’t tell you specific information about your case. To learn more about what survival rates mean for you, talk to your healthcare provider.

How can I take care of myself?

Having cancer comes with a range of emotions. However you feel is OK. Some days, you might feel fine. Other days, it might be hard to get out of bed. It’s important to listen to your body. These suggestions might help:

• Eat lots of fruits, vegetables and whole grains.
• Get plenty of sleep.
• Manage stress with yoga, meditation or art therapy.
• Rest when you need to.
• Seek support from cancer survivorship programs.
• Talk with others who have similar diagnoses.

When should I see my healthcare provider?

You’ll see your healthcare provider for routine check-ups. But you should let them know if you develop any new symptoms or if your existing symptoms get worse.

What questions should I ask my doctor?

If you have luminal A breast cancer, here are some questions you may want to ask your healthcare provider:

• What grade or stage of cancer do I have?
• Has the cancer spread to other areas?
• What treatments do you recommend for the type of breast cancer I have?
• How long will treatment take?
• How often will I need to come in for checkups?
• Will I have any treatment side effects?