Lobular Breast Cancer (Invasive Lobular Carcinoma)

Lobular breast cancer (also called invasive lobular carcinoma) is breast cancer that starts in the milk-producing gland, or lobules, of your breast and has spread into surrounding breast tissue. It can be cured if caught early. Left untreated, lobular breast cancer spreads to nearby lymph nodes, and then to other areas of your body.


Front and side views of components of breast tissue including fat, lobules, ducts, nipple and areola.
Lobular breast cancer begins in the milk-producing glands (lobules) of the breast.

What is lobular breast cancer?

Lobular breast cancer (also called invasive lobular carcinoma, or ILC) is breast cancer that starts in the milk-producing gland, or lobules, of your breast and has spread into surrounding breast tissue. It accounts for about 10% to 15% of all breast cancers and is the second most common type of breast cancer. Left untreated, lobular breast cancer spreads to nearby lymph nodes, and then to other areas of your body.

What’s the difference between invasive lobular breast cancer and invasive ductal carcinoma?

Invasive lobular breast cancer tends to grow in a single-file pattern of cells. Invasive ductal carcinoma typically forms a mass or lump.


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Who’s affected by lobular breast cancer?

Women and people assigned female at birth (AFAB) who are age 55 and older are most likely to develop invasive lobular carcinoma. Men and people who are assigned male at birth can develop ILC, too, though it’s rare. Transwomen have a higher risk of developing breast cancer than cisgender men. Conversely, transmen have a lower risk compared to cisgender women.

Unlike invasive ductal carcinoma (IDC), invasive lobular carcinoma usually occurs later in life. Many people are in their early 60s at the time of their diagnosis.

Symptoms and Causes

What are lobular breast carcinoma symptoms?

Unlike other breast cancer types, lobular breast cancer doesn’t form lumps in your breast tissue or under your arm. Instead, it may cause the following symptoms:

  • Hard or thickened area inside of your breast or underarm.
  • Your nipple is inverted, meaning it points into your breast instead of pointing out.
  • Dimpling, dent or puckering skin on a part of your breast.
  • Changes in breast size or shape.
  • A feeling of warmth or redness.
  • Nipple discharge.
  • An area of swelling or fullness in your breast.
  • A lump near your armpit.
  • Breast pain.

Many of these symptoms are similar to other less serious medical issues. Some of these symptoms, like an inverted nipple, are also similar to other serious conditions such as inflammatory breast cancer (IBC). Talk to a healthcare provider any time you notice a change in your breasts.


What causes lobular breast cancer?

Experts know that ILC occurs when cells in your breast develop mutations in their DNA. But they aren’t exactly sure what causes those mutations to occur. There are factors that could increase your risk for invasive lobular carcinoma, including:

  • Age. Most people who are diagnosed with invasive lobular carcinoma are over the age of 55.
  • Sex. Women and people AFAB are more likely to develop ILC.
  • Hormone therapy. Women and people AFAB who use hormone therapy after menopause may have an increased risk of invasive lobular carcinoma.
  • Genetic factors. Certain inherited genes could play a role in whether or not you get breast cancer. A rare condition called hereditary diffuse gastric cancer syndrome can increase your risk for both invasive lobular carcinoma and stomach cancer.

How does invasive lobular carcinoma spread?

The term “invasive” means the cancer started in the lobules or ducts of your breast, but spread to surrounding breast tissue. Eventually, the cancer can also spread to lymph nodes, organs and other areas throughout your body.

Diagnosis and Tests

How do healthcare providers diagnose lobular breast cancer?

Healthcare providers may do the following tests to diagnose this condition:

  • Mammogram. This test is a low-dose X-ray that detects abnormalities in your breast tissue.
  • Ultrasound. This imaging test uses sound waves to capture pictures of your breast tissue. Ultrasound may be used as a standalone test or in combination with mammography.
  • Magnetic resonance imaging (MRI). Your healthcare provider may request an MRI, which uses radio waves and magnets to take detailed pictures inside of your body.
  • Biopsy. In order to confirm the cancer is present, your healthcare provider may take a small sample of breast tissue and send it to a pathology lab for analysis.

What are the stages of invasive lobular carcinoma?

Healthcare providers use cancer staging systems to plan treatment. Invasive lobular carcinoma is divided into four stages. Staging is based on several factors, including the size of the tumor, where it’s located and how far it has spread:

  • Stage 1: The tumor is up to 2 centimeters (cm) across and may have spread to nearby lymph nodes.
  • Stage 2: At this stage, the tumor may be about 2 cm across and the cancer has spread to nearby lymph nodes. Or the tumor has grown up to 5 cm across and the cancer hasn’t spread to nearby lymph nodes.
  • Stage 3: The cancer may have spread to lymph nodes, but hasn’t spread to distant sites like other organs in your body. In some cases, the cancer may have spread into your chest wall.
  • Stage 4: The cancer may or may not have spread to nearby lymph nodes. The cancer has spread to distant lymph nodes or organs, which may include your liver, lungs, bone or brain. Stage 4 is also referred to as metastatic breast cancer.

Management and Treatment

How do healthcare providers treat lobular breast cancer?

There are two main categories of ILC treatment — local and systemic. Local treatments target the tumor and the surrounding areas, while systemic treatments travel through your body to kill any cancer cells that have spread throughout it.

Local treatments for invasive lobular carcinoma

Local treatments include:

  • Surgery. This is usually the first line of treatment recommended for invasive lobular carcinoma. A lumpectomy or mastectomy is performed to remove the tumor. During the procedure, your surgeon will also check to see if the cancer has spread to your lymph nodes.
  • Radiation therapy. This treatment focuses high-energy radiation rays at your breast, underarm regions and surrounding areas. Radiation therapy is often recommended after surgery to destroy any remaining cancer cells.

Systemic treatments for lobular breast cancer

Systemic treatments include:

  • Chemotherapy. This treatment uses drugs to kill cancer cells. It may be used before surgery to shrink the tumor. Or it may be used after surgery to kill any remaining cancer cells.
  • Targeted therapy. This type of treatment targets certain characteristics of cancer cells in order to destroy them. Targeted therapy is less likely than chemotherapy to destroy healthy cells.
  • Antihormone therapy. If the cancer tests positive for hormone receptors, which most ILCs do, then antihormone therapy may be a good option. This approach lowers the amount of estrogen in your body. As a result, it blocks or reduces the growth of breast cancer cells.
What are treatment side effects?

As with any cancer treatment, people who undergo treatment for invasive lobular carcinoma may experience some side effects. These side effects depend on the type of treatment you undergo, how advanced your cancer is, your body’s healing capacity and other factors.

People who undergo surgery for invasive lobular carcinoma may develop infections, blood clots, allergies to anesthesia or other complications. Radiation therapy is often associated with fatigue, nausea and skin irritation.

People who undergo chemotherapy may develop several side effects, including:

For people receiving antihormone therapy, the most common side effects are hot flashes, joint pain, weight changes, mood changes, vaginal dryness or discharge, and a decrease in sexual desire.

How long does it take to recover from invasive lobular carcinoma treatment?

Healing times can vary for each individual. If you’ve had surgery, recovery usually takes about two to four weeks. Chemotherapy, radiation therapy and targeted therapy may take several weeks to several months depending on your specific situation. Ask your healthcare provider what to expect in terms of recovery.


How can I reduce my risk?

Although you can’t prevent invasive lobular carcinoma altogether, there are things you can do to reduce your risk. For example:

  • Eat a healthy diet.
  • Avoid smoking.
  • Drink alcohol in moderation.
  • Stay at a healthy weight.
  • Exercise regularly.

Outlook / Prognosis

What can I expect if I have this condition?

Fortunately, ILC is a slow-growing cancer, so there’s the opportunity to catch it in the early stages when treatment is most successful. Invasive lobular carcinoma prognosis depends on several factors, including the size of the tumor, its location and whether or not it has spread. If you’ve recently been diagnosed with ILC, talk with your healthcare provider about treatment options as soon as possible.

Can lobular breast cancer be cured?

Yes. Invasive lobular carcinoma can be cured when caught and treated early.

What is the survival rate for lobular breast cancer?

The five-year survival rate for invasive lobular carcinoma is high compared to other types of cancer — nearly 100% when treated early. If the cancer has spread to nearby tissues, the five-year survival rate is about 93%. If it has metastasized to other areas of your body, the five-year survival rate is 22%.

It’s important to note that survival rates can’t tell you how long you’ll live. These estimates are based on people who’ve had invasive lobular carcinoma in the past. To learn more about your unique case, talk to your healthcare provider.

Living With

When should I see my healthcare provider?

You should schedule a consultation with your healthcare provider any time you notice sudden or unusual changes in your breasts. Your healthcare provider can perform tests to determine if you have breast cancer.

If you’re already undergoing treatment for ILC, call your healthcare provider if you develop any worrisome symptoms, such as chest pain, confusion, chills, high fever, shortness of breath (dyspnea) bone pain or abdominal pain.

What questions should I ask my doctor?

If you’ve been diagnosed with invasive lobular carcinoma, you’ll want to gather as much information as possible. Here are some questions you can ask your healthcare provider:

  • What stage is my invasive lobular carcinoma?
  • How far has it spread?
  • What are my treatment options?
  • How long will my treatment take?
  • Will I be able to work while undergoing cancer treatment?
  • What’s my outlook?

A note from Cleveland Clinic

Lobular breast cancer (lobular carcinoma, invasive lobular carcinoma, ILC) is breast cancer that starts in the milk-producing gland or lobes of your breasts. This is a slow-growing cancer that can be cured if it’s detected and treated before it can spread from your breasts to nearby lymph nodes. Lobular carcinoma symptoms may resemble other less serious issues. That’s why it’s important for you to watch for changes in your breast. If you notice changes, don’t hesitate to talk to a healthcare provider.

Medically Reviewed

Last reviewed by a Cleveland Clinic medical professional on 09/20/2022.

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