Invasive lobular carcinoma (ILC)

Overview

Invasive lobular carcinoma (ILC) is a type of breast cancer. It causes a growth of cells in the milk-producing glands of the breast. These glands are called lobules.

Invasive lobular carcinoma is an invasive cancer, which means the cancer cells have broken out of the lobule where they formed and have grown into the surrounding breast tissue. The cells can spread to the lymph nodes and other areas of the body.

Invasive lobular carcinoma, also called infiltrating lobular carcinoma, makes up a small portion of all breast cancers. Most breast cancers are invasive ductal carcinomas. These cancers grow in the tubes that can carry breast milk to the nipple, called ducts.

Compared with the ductal type, invasive lobular carcinoma is less likely to cause a lump in the breast. It's also more likely to be missed on imaging tests, such as mammograms. This can make detecting the cancer more difficult. It's often diagnosed when it grows larger or spreads to the lymph nodes.

Even with these differences, lobular breast cancer and ductal breast cancer have similar survival rates. The prognosis and treatment options for both types are the same.

Treatments for invasive lobular carcinoma include surgery, radiation therapy and medicines, such as estrogen blocker therapy, chemotherapy and targeted therapy.

Many invasive lobular carcinomas can be cured, especially when the cancer is only in the breast. But cancer that spreads to other parts of the body is harder to treat. A cure may not be possible for advanced cancer, but there are treatments that can slow its growth and extend your life.

Types

Types of invasive lobular carcinoma (ILC) include:

• Classic. Classic invasive lobular carcinomas tend to grow slowly. Most use hormones to help them grow, so healthcare professionals say they are hormone receptor (HR) positive cancers. The classic type isn't likely to make extra HER2, so these cancers are usually HER2 negative.
• Pleomorphic. Pleomorphic invasive lobular carcinomas tend to grow quickly. The pleomorphic type is often HR positive and HER2 negative, but sometimes can be HR negative or HER2 positive.

Symptoms

Invasive lobular carcinoma (ILC) often doesn't cause any symptoms at first. This type of breast cancer is less likely to cause something that feels like a lump in the breast. It may feel more like an area of thickening. Other symptoms are similar to other types of breast cancer.

Invasive lobular carcinoma signs and symptoms may include:

• An area of thickening in part of the breast that makes it feel different from the surrounding tissue.
• A nipple that looks flattened or turns inward.
• Changes in the color of the breast skin. In people with white skin, the breast skin may look pink or red. In people with brown and Black skin, the breast skin may look darker than the other skin on the chest or it may look red, purple or brown.
• Change in the size, shape or appearance of a breast.
• Changes to the skin over the breast, such as skin that looks dimpled or looks like an orange peel.
• Peeling, scaling, crusting or flaking of the skin on the breast.

When to see a doctor

Make an appointment with a doctor or other healthcare professional if you notice a change in your breasts. Changes to look for may include a lump, an area of puckered or otherwise unusual skin, a thickened region under the skin, and nipple discharge. Even if you've recently had a mammogram, don't wait until your next appointment to report these concerns to your healthcare team.

Causes

The exact cause of invasive lobular carcinoma (ILC) often isn't known. Healthcare professionals know that it starts when changes happen in the DNA inside breast cells. But exactly what causes these genetic changes isn't always known.

How DNA changes lead to cancer

A cell's DNA holds the instructions that tell a cell what to do. In healthy cells, the DNA gives instructions to multiply at a set rate. The instructions also tell the cells to die off at a set time. In cancer cells, changes happen in the DNA. The changes alter the instructions for multiplying and dying. The result is that the cancer cells multiply faster than healthy cells. And they can keep living when healthy cells would die. This causes too many cells in the area.

Most invasive lobular carcinoma cells have genetic changes that affect a protein called epithelial cadherin, which is often shortened to E-cadherin. E-cadherin helps cells stick together. When it doesn't work as it should, the cancer cells spread out in the breast tissue instead of forming a lump.

How DNA changes occur

For most people, the DNA changes that cause invasive lobular carcinoma happen by chance. Sometimes the changes that lead to cancer are passed from parents to children. Healthcare professionals say they are inherited or hereditary.

Not everyone with an inherited DNA change gets cancer. And most people who get cancer don't have an inherited DNA change. It's likely that invasive lobular carcinoma is caused by a mix of genetic and environmental factors. More research is needed to find the exact cause.

How the cancer becomes invasive and spreads

The DNA changes that lead to invasive lobular carcinoma cause a growth inside a milk-producing lobule in the breast. The cells can break out of the lobule and grow into nearby tissue.

Over time, cancer cells can break away and spread to other parts of the body. When cancer spreads, it's called metastatic cancer. Like other breast cancers, invasive lobular carcinoma most often spreads to the bones, lungs, liver and brain. But it also can spread to places where other breast cancers don't typically go, such as the stomach, ovaries, and the lining of the abdomen, called the peritoneum. This cancer also can spread to the thin layers of tissue and fluid that surround the brain and spinal cord, called the leptomeninges.

Risk factors

The risk factors for invasive lobular carcinoma (ILC) are similar to the risk factors for breast cancer in general. Factors that may raise the risk include:

• A family history of breast cancer. If a parent, sibling or child had breast cancer, your risk of breast cancer is increased. The risk is higher if your family has a history of getting breast cancer at a young age. The risk also is higher if you have multiple family members with breast cancer. Still, most people diagnosed with breast cancer don't have a family history of the disease.
• A personal history of breast cancer. If you've had cancer in one breast, you have an increased risk of getting cancer in the other breast.
• A personal history of breast conditions. Certain breast conditions are markers for a higher risk of breast cancer. These conditions include lobular carcinoma in situ (LCIS) and atypical hyperplasia of the breast. If you've had a breast biopsy that found one of these conditions, you have an increased risk of breast cancer.
• Being female. Women are much more likely than men are to get breast cancer. However, everyone is born with some breast tissue, so anyone can get breast cancer, including men. Invasive lobular carcinoma can happen in men, but they are much more likely to have the ductal type of breast cancer.
• Beginning your period at a younger age. Beginning your period before age 12 increases your risk of breast cancer.
• Beginning menopause at an older age. Beginning menopause after age 55 increases the risk of breast cancer.
• Dense breast tissue. Breast tissue is made up of fatty tissue and dense tissue. Fatty tissue is made of fat. Dense tissue is made of milk glands, milk ducts and fibrous tissue. If you have dense breasts, you have more dense tissue than fatty tissue in your breasts. Having dense breasts increases the risk of developing breast cancer and makes it harder to detect cancer on a mammogram. Talk with your healthcare team about other tests you might have in addition to mammograms to look for breast cancer.
• Drinking alcohol. Drinking alcohol increases the risk of breast cancer. There is no safe amount of alcohol when it comes to breast cancer. The more alcohol you drink, the greater your risk.
• Having your first child at an older age. Giving birth to your first child after age 30 may increase the risk of breast cancer.
• Having never been pregnant. Having been pregnant one or more times lowers the risk of breast cancer. Never having been pregnant increases the risk.
• Inherited DNA changes that increase cancer risk. Certain DNA changes that increase the risk of breast cancer can be passed from parents to children. The DNA changes linked to an increased risk of invasive lobular carcinoma include BRCA2, which also raises the risk of ovarian cancer, and CDH1, which also raises the risk of stomach cancer.
• Menopausal hormone therapy. Taking certain hormone therapy medicines to manage the symptoms of menopause may increase the risk of breast cancer. The risk is linked to hormone therapy medicines that combine estrogen and progesterone.
• Older age. The risk of breast cancer increases as you age. Invasive lobular carcinoma tends to happen at an older age compared with other types of breast cancer. It happens most often in those who have been through menopause.
• Obesity. Having obesity increases the risk of breast cancer.
• Radiation exposure. Radiation treatments to the chest as a child or young adult raises the risk of breast cancer.

Prevention

You can take steps to help lower your risk of invasive lobular carcinoma and other types of breast cancer.

Ask about breast cancer screening

Talk with a healthcare professional about when to begin breast cancer screening. Ask about the benefits and risks of screening. Together, you can decide what breast cancer screening tests are right for you.

Become familiar with your breasts

Do occasional breast self-exams so that you know what your breasts typically feel like. If there is a new change, a lump or something not typical in your breasts, report it to a healthcare professional right away.

Breast awareness through self-exams can't prevent breast cancer. But it may help you to better understand the look and feel of your breasts. This might make it more likely that you'll notice if something changes.

Drink alcohol in moderation, if at all

If you choose to drink alcohol, limit how often you drink and keep the amount small. For overall health, drink one or fewer drinks a day. Do not drink every day. The less you drink, the better.

For breast cancer prevention, there is no safe amount of alcohol. So if you're concerned about your breast cancer risk, you may choose to not drink alcohol.

Exercise most days of the week

Aim for at least 30 minutes of exercise on most days of the week. If you haven't been active lately, ask a healthcare professional whether it's OK and start slowly.

Limit menopausal hormone therapy

Hormone therapy that uses a combination of estrogen and progesterone may increase the risk of breast cancer. Talk with a healthcare professional about the benefits and risks of hormone therapy.

Maintain a healthy weight

If your weight is healthy, work to maintain that weight. If you need to lose weight, ask a healthcare professional about healthy ways to lower your weight. In general, try to eat fewer calories every day and slowly increase how much you exercise.

Talk with a healthcare professional about your cancer risk

If you have a family history of breast cancer or think that you may have an increased risk of breast cancer, talk about it with your healthcare professional. Preventive medicines, surgery and more-frequent screening may be options for people with a high risk of breast cancer.

Living with invasive lobular carcinoma (ILC)?

Connect with others like you for support and answers to your questions in the Breast Cancer support group on Mayo Clinic Connect, a patient community.

Breast Cancer Discussions

See more discussions