Luminal B Breast Cancer

What is luminal B breast cancer?

Luminal B breast cancer is a subtype of hormone receptor-positive (HR+) breast cancer. Luminal B breast cancer cells have proteins (receptors) inside them that cause cancer to grow when the hormone estrogen attaches to them. The term “luminal” refers to cells in the inner lining of your breast ducts.

Characteristics

Luminal B cancer cells are:

• Positive for estrogen. Luminal B cancer cells may have estrogen receptor (ER) proteins.
• Negative for progesterone. Unlike luminal A cells, luminal B cells may have little or no progesterone receptor (PR) proteins.
• HER2-positive (HER2+) or HER2-negative (HER2-). Luminal B cancer cells may (or may not) have a protein called human epidermal growth factor receptor 2 (HER2). HER2 is a part of normal cell growth. But some breast cancer cells make too much of it.
• High in Ki-67. Ki-67 is a protein you can only find in rapidly dividing cells. That’s one reason why luminal B breast cancers typically grow faster than luminal A breast cancers.
• Higher grade. Luminal B cancers are larger, more aggressive and more likely to recur (come back) than luminal A cancers.

All these letters, numbers and abbreviations represent a molecular-level profile of the cancer cells in your breast. Healthcare providers use this information to develop personalized treatments and predict treatment outcomes.

How common is luminal B breast cancer?

Luminal B breast cancer makes up about 15% to 20% of all breast cancer cases. It’s less common than luminal A breast cancer.

What are the symptoms of luminal B breast cancer?

Healthcare providers often detect luminal B breast cancer through screenings before symptoms develop. But if you do notice symptoms, they might include:

• A firm, rubbery lump in your breast that doesn’t move freely.
• Pain in one or both breasts.
• Nipple discharge.
• Skin dimpling, thickening or discoloration.
• Swelling under your arm.

What causes luminal B breast cancer?

Luminal B breast cancer happens when healthy breast cells change and grow uncontrollably. But experts don’t know exactly why this happens.

Luminal B cells contain proteins that cause cancer growth when estrogen attaches to them. So, you have a slightly higher risk of developing luminal B if you started your period early, went through menopause later than expected or received HRT.

Other factors that might increase your risk for luminal B breast cancer include:

• A family history of breast or ovarian cancer.
• Being over the age of 50.
• Having dense breast tissue.
• Inheriting certain genetic variations (changes).
• Past radiation therapy to your chest or breasts.

How is luminal B breast cancer diagnosed?

If you develop breast cancer symptoms or receive suspicious mammogram results, a healthcare provider will start with a physical exam. They’ll likely order additional imaging tests like a diagnostic mammogram, ultrasound or MRI.

Your healthcare provider will also do a breast biopsy. During this procedure, they’ll take a sample of your breast tissue and send it to a lab for analysis.

A pathologist will test your tissue sample for cancer cells. If they find cancer cells, they’ll run hormone receptor tests and HER2 tests to determine the cancer subtype. Among these tests, immunohistochemistry (a type of immunostaining) is the most common. It uses fluorescent dyes and enzymes to highlight specific molecules in your breast cells.

Running tests on your tissue sample can tell your healthcare team what type of treatments might work. It can also tell them how likely it is that cancer will return after treatment.

How is luminal B breast cancer treated?

Other luminal B breast cancer treatments include:

• Hormone therapy. This is the most common treatment for luminal B breast cancer. Because luminal B is hormone receptor-positive (HR+), hormone therapy can target the estrogen that fuels the cancer’s growth.
• 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.
• Targeted therapy. Select luminal B cancers may benefit from targeted treatments depending on the stage and overall receptor profile.
• Chemotherapy. Select high-risk people benefit from adjuvant chemotherapy to kill cancer cells that other treatments didn’t destroy. Your healthcare provider can tell you if this is an option for you.

Luminal B cancer treatment varies depending on your situation and lab test results. For example, someone with HER2+ breast cancer will need a different treatment than someone with HER2- breast cancer.

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

You can’t change certain risk factors, like family history. But doing these things might reduce your risk for luminal B breast cancer:

• Avoid smoking.
• Increase physical activity.
• Limit alcohol intake.
• Maintain a weight that’s healthy for you.

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

The prognosis for people with luminal B breast cancer depends on how advanced the tumor is at the time of diagnosis. Like most cancers, the sooner you begin treatment, the better your outlook.

Depending on the stage at diagnosis, luminal B breast cancer may be curable, meaning it can go into remission with treatment. But it can also come back.

The risk of cancer recurrence varies depending on several factors like stage and growth rate. For this reason, your provider will continue to monitor your health, even if you’re in remission. They may also recommend additional therapies after surgery and radiation to reduce your risk of cancer returning.

Luminal B breast cancer survival rates

The five-year survival rate for HR+/HER2+ (hormone receptor-positive/human epidural growth factor receptor 2-positive) breast cancer is 91.5%. That means that over 91% of people with this type of cancer are alive five years after their diagnosis.

The five-year survival rate for HR+/HER2- (hormone receptor-positive/human epidural growth factor receptor 2-negative) breast cancer is 95.1%.

It’s important to understand that survival rates are only estimates. They can’t tell you how long you’ll live or how you’ll respond to a certain treatment. If you want to know what survival rates mean for you, talk to your healthcare provider.

How can I take care of myself?

Living with luminal B breast cancer can be exhausting. You might feel OK one day and completely overwhelmed the next. It’s important to take good care of yourself throughout your diagnosis and treatment. Consider these suggestions:

• Eat well. Include whole grains, fresh fruits and vegetables into your nutrition plan.
• Find ways to manage stress. Practice meditation or other mindfulness activities to improve your overall well-being.
• Get lots of rest. This includes getting enough sleep and taking breaks throughout the day.
• Join a supportive community. Ask your healthcare provider about cancer survivorship programs. These groups give you an opportunity to meet other people who are going through similar things.

When should I see my healthcare provider?

You should tell your healthcare provider any time you develop new or changing symptoms. This includes pain or weakness in another part of your body.

What questions should I ask my doctor?

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

• Is my cancer HER2-positive or HER2-negative?
• What grade or stage of cancer do I have?
• What are my treatment options?
• How will treatment work?
• How often do I need to see you for follow-ups?
• What treatment side effects should I be aware of?