Lobular carcinoma in situ (LCIS)

Date Updated: 07/28/2025

Overview

Lobular carcinoma in situ is a growth of cells that happens in a milk gland in the breast tissue. The cells undergo changes that make them look different from typical cells. Lobular carcinoma in situ, which is often shortened to LCIS, isn't cancer. But having lobular carcinoma in situ increases the risk of getting breast cancer in the future.

Lobular carcinoma in situ usually isn't found on a mammogram or felt during a breast exam. The condition is most often found after a procedure to remove some breast tissue, such as a breast biopsy or a lumpectomy.

Lobular carcinoma in situ increases the risk of breast cancer in both breasts. If you're diagnosed with lobular carcinoma in situ, you may need increased breast cancer screening. You also may want to consider treatments to reduce your risk of developing invasive breast cancer.

Symptoms

Lobular carcinoma in situ doesn't cause signs or symptoms. It's usually found after a procedure to remove some breast tissue, such as a breast biopsy or a lumpectomy. Lobular carcinoma in situ, also called LCIS, isn't cancer. It's a sign that you have an increased risk of breast cancer in the future.

When to see a doctor

Make an appointment with a doctor or other healthcare professional if you notice a change in your breasts. Changes may include a lump, an area of puckered or otherwise unusual skin, a thickened region under the skin, and nipple discharge.

Ask when you should consider breast cancer screening and how often it should be repeated. Most healthcare professionals recommend routine breast cancer screening beginning in your 40s.

Causes

It's not clear what causes lobular carcinoma in situ, also called LCIS. Lobular carcinoma in situ begins when cells in a milk-producing gland of a breast, called a lobule, develop changes in their DNA. These changes cause the cells to look different from healthy cells. The changed cells remain in the lobule and don't extend into, or invade, nearby breast tissue.

If you have lobular carcinoma in situ, it doesn't mean that you have cancer. But having lobular carcinoma in situ increases your risk of breast cancer and makes it more likely that you may develop invasive breast cancer.

The risk of breast cancer in women diagnosed with lobular carcinoma in situ is thought to be approximately 25% to 30%. For comparison, the risk of developing breast cancer for women in general is thought to be 13%.

Your individual risk of breast cancer is based on many factors. Talk to your healthcare team to better understand your personal risk of breast cancer.

Risk factors

Lobular carcinoma in situ is more common in those who haven't gone through menopause yet.

Prevention

Lobular carcinoma in situ, also called LCIS, increases the risk of breast cancer. If you're worried about breast cancer, take steps to reduce your risk, such as:

Ask about breast cancer screening

Talk with your doctor or other 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.

Breast cancer screening often involves having regular mammograms. If you have a history of lobular carcinoma in situ, talk with your healthcare professional about whether additional imaging tests, such as MRI, might be right for you.

Become familiar with your breasts through breast self-exams

You may choose to become familiar with your breasts by occasionally inspecting them during a breast self-exam for breast awareness. If you find a new change, lumps or other unusual signs in your breasts, tell a healthcare professional right away.

Breast awareness 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 the amount you drink to no more than one drink a day. For breast cancer prevention, there is no safe amount of alcohol. So if you're very 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 your healthcare professional whether exercising is OK and start slowly.

Limit hormone therapy during menopause

Combination hormone therapy for menopause symptoms may increase the risk of breast cancer. Talk with a healthcare professional about the benefits and risks of hormone therapy.

Some people have symptoms during menopause that cause discomfort. These people may decide that the risks of hormone therapy are acceptable to get relief. To reduce the risk of breast cancer, use the lowest dose of hormone therapy possible for the shortest amount of time.

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. Eat fewer calories and slowly increase the amount you exercise.

Diagnosis

Lobular carcinoma in situ, also called LCIS, is most often diagnosed during a breast biopsy. A breast biopsy is a procedure to remove a sample of breast tissue for testing. Lobular carcinoma in situ often can't be detected on a mammogram or felt during a breast exam.

Types of breast biopsy that may be used include:

Core needle biopsy. A healthcare professional uses a thin, hollow needle to remove several tiny tissue samples from the breast. Imaging tests, such as ultrasound or MRI, are often used to help guide the needle used in a core needle biopsy.
Surgical biopsy. A surgeon may perform an operation to remove the tissue sample for testing.

The tissue removed during a biopsy is sent to a lab. In the lab, doctors that specialize in analyzing blood and body tissues, called pathologists, closely examine the cells. They can determine if you have lobular carcinoma in situ.

Treatment

Treatment for lobular carcinoma in situ, also called LCIS, often involves close monitoring for signs of cancer. Medicines or surgery may be used to lower the risk of breast cancer. Your healthcare team considers many factors when creating a treatment plan. These factors may include your overall health and your preferences.

Careful monitoring for breast cancer

If you've been diagnosed with lobular carcinoma in situ, you may need more frequent exams to look for signs of breast cancer. Exams may include:

Annual mammograms.
Breast exams by a healthcare professional every 6 to 12 months.
Monthly breast self-exams to develop breast awareness and to detect any breast changes. (7)
Additional breast cancer screening tests based on your other risk factors for breast cancer. These other tests may include breast MRI, molecular breast imaging and other supplemental breast imaging tests. Which test is best for you may depend on your risk factors for breast cancer, your family history of breast cancer, whether you have DNA changes that increase the risk of breast cancer and whether your mammogram images show that you have dense breasts.

Medicine to lower the risk of breast cancer

Medicines that block the hormone estrogen in the body can lower the risk of breast cancer. Most breast cancers use estrogen and other hormones to help the cancer grow. Blocking estrogen helps stop cancer from forming.

Hormone-blocking medicines that are used to lower breast cancer risk include:

Tamoxifen.
Raloxifene (Evista).
Anastrozole (Arimidex).
Exemestane (Aromasin).

These medicines are typically taken daily for five years to reduce the risk of breast cancer. The medicine tamoxifen is sometimes taken in a lower dose every other day. Talk with your healthcare team about which medicine is best for you.

Surgery to lower the risk of breast cancer

If you have a very high risk of breast cancer, your healthcare team might recommend surgery to lower your risk. Your risk might be high if you have a strong family history of breast cancer. Your risk also may be high if DNA changes that increase the risk of breast cancer run in your family. One operation that can lower the risk of breast cancer is surgery to remove one or both breasts. This procedure is called a risk-reducing mastectomy or a prophylactic mastectomy.

Treatment for pleomorphic lobular carcinoma in situ

Surgery is often recommended for a specific type of lobular carcinoma in situ called pleomorphic lobular carcinoma in situ. This type is thought to carry a greater risk of breast cancer.

Pleomorphic lobular carcinoma in situ isn't common. Unlike other kinds of lobular carcinoma in situ, it can be seen on a mammogram.

If a biopsy confirms that you have pleomorphic lobular carcinoma in situ, your healthcare team will likely recommend surgery. One option may be an operation to remove the area of concerning cells. This procedure is called a lumpectomy. Another option may be an operation to remove nearly all of the breast tissue. This procedure is called a mastectomy.

To decide which treatment is best for you, your healthcare team considers how much of your breast tissue needs to be removed, the results of your mammogram, whether you have a strong family history of cancer and your age.

Coping and support

Although lobular carcinoma in situ is not cancer, it can cause worry about the increased risk of a future breast cancer. Coping with the diagnosis may mean finding a long-term way to manage any fear and worry.

To help you cope with a diagnosis of lobular carcinoma in situ, also called LCIS, try to:

Learn enough to make decisions about your care

Ask your healthcare team questions about your lobular carcinoma in situ and what it means for your breast cancer risk. Use this information to research your treatment options.

Look to reputable sources of information, such as the U.S. National Cancer Institute, to find out more. This may make you feel more confident as you make choices about your care.

Go to all of your screening appointments

You may feel anxious before your breast cancer screening exams. Don't let this stop you from going to all of your appointments. Instead, plan ahead and expect that you'll be anxious.

To cope with feeling anxious, spend time doing things you enjoy in the days before your appointment. Spend time with friends or family, or find quiet time for yourself.

Control what you can about your health

Make healthy changes to your lifestyle, so you can feel your best. For instance, choose a healthy diet that focuses on fruits, vegetables and whole grains. Try to be active for 30 minutes most days of the week. Get enough sleep each night so that you wake feeling rested.

Preparing for your appointment

Make an appointment with a doctor or other healthcare professional if you notice a lump or any other unusual change in your breasts.

Here's some information to help you get ready for your appointment.

What you can do

Write down any symptoms you're experiencing, and for how long. If you have a lump, write down when you first noticed it and whether it seems to have grown.
Write down your family history of cancer. Note any family members who have had cancer. Note how each member is related to you, the type of cancer, the age at diagnosis and whether each person survived.
Make a list of all medicines, vitamins or supplements that you're taking. If you're currently taking or have previously taken hormone replacement therapy, tell your healthcare provider.
Consider taking a family member or friend along. Sometimes it can be difficult to absorb all the information provided during an appointment. Someone who comes with you may remember something that you missed or forgot.
Write down questions to ask your healthcare professional.

Your time with your healthcare professional is limited. Prepare a list of questions so that you can make the most of your time together. List your questions from most important to least important in case time runs out. For lobular carcinoma in situ, some basic questions to ask include:

How much does lobular carcinoma in situ increase my risk of breast cancer?
Do I have any additional risk factors for breast cancer?
How often should I be screened for breast cancer?
What types of screening technology will be most effective in my case?
Am I a candidate for medicines that reduce the risk of breast cancer?
What are the possible side effects or complications of these medicines?
Which medicine do you recommend for me, and why?
How will you monitor me for treatment side effects?
Am I a candidate for preventive surgery?
In general, how effective is the treatment you're recommending in women with a diagnosis similar to mine?
What lifestyle changes can help reduce my risk of cancer?
Do I need a second opinion?
Should I see a genetic counselor?

In addition to the questions that you've prepared, don't hesitate to ask other questions you think of during your appointment.

What to expect from your doctor

Be prepared to answer some questions about your symptoms and your health, such as:

Do you have a breast lump that you can feel?
When did you first notice this lump?
Has the lump grown or changed over time?
Have you noticed any other unusual changes in your breast, such as discharge, swelling or pain?
Have you gone through menopause?
Are you using or have you used any medicines or supplements to relieve the symptoms of menopause?
Have you been diagnosed with any previous breast conditions, including noncancerous conditions?
Have you been diagnosed with any other medical conditions?
Do you have any family history of breast cancer?
Have you or your close female relatives ever been tested for BRCA gene changes?
Have you ever had radiation therapy?
What is your typical daily diet, including alcohol intake?
Are you physically active?