Lobular carcinoma in situ (LCIS)


Lobular carcinoma in situ (LCIS) is an uncommon condition in which abnormal cells form in the milk glands (lobules) in the breast. LCIS isn't cancer. But being diagnosed with LCIS indicates that you have an increased risk of developing breast cancer.

LCIS usually doesn't show up on mammograms. The condition is most often discovered as a result of a breast biopsy done for another reason, such as a suspicious breast lump or an abnormal mammogram.

Women with LCIS have an increased risk of developing invasive breast cancer in either breast. If you're diagnosed with LCIS, your doctor may recommend increased breast cancer screening and may ask you to consider medical treatments to reduce your risk of developing invasive breast cancer.

Lobular carcinoma in situ


LCIS doesn't cause signs or symptoms. Rather, your doctor might discover incidentally that you have LCIS — for instance, after a biopsy to assess a breast lump or an abnormal area found on a mammogram.

When to see a doctor

Make an appointment with your doctor if you notice a change in your breasts, such as a lump, an area of puckered or otherwise unusual skin, a thickened region under the skin, or nipple discharge.

Ask your doctor when you should consider breast cancer screening and how often it should be repeated. Most groups recommend considering routine breast cancer screening beginning in your 40s. Talk with your doctor about what's right for you.


It's not clear what causes LCIS. LCIS begins when cells in a milk-producing gland (lobule) of a breast develop genetic mutations that cause the cells to appear abnormal. The abnormal cells remain in the lobule and don't extend into, or invade, nearby breast tissue.

If LCIS is detected in a breast biopsy, it doesn't mean that you have cancer. But having LCIS 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 LCIS is thought to be approximately 20 percent. Put another way, for every 100 women diagnosed with LCIS, 20 will be diagnosed with breast cancer and 80 won't be diagnosed with breast cancer. The risk of developing breast cancer for women in general is thought to be 12 percent. Put another way, for every 100 women in the general population, 12 will be diagnosed with breast cancer.

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

Main parts of the breast


Lobular carcinoma in situ (LCIS) may be present in one or both breasts, but it usually isn't visible on a mammogram. The condition is most often diagnosed as an incidental finding when you have a biopsy done to evaluate some other area of concern in your breast.

Types of breast biopsy that may be used include:

  • Core needle biopsy. A radiologist or surgeon uses a thin, hollow needle to remove several tiny tissue samples. Imaging techniques, 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 suspicious cells for examination.

The tissue removed during your biopsy is sent to a laboratory where doctors that specialize in analyzing blood and body tissues (pathologists) closely examine the cells to determine if you have LCIS.

Core needle biopsy


A number of factors, including your personal preferences, come into play when you decide whether to undergo treatment for lobular carcinoma in situ (LCIS).

There are three main approaches to treatment:

  • Careful observation
  • Taking a medication to reduce cancer risk (preventive therapy)
  • Surgery


If you've been diagnosed with LCIS, your doctor may recommend more frequent exams to closely monitor your breasts for signs of cancer. This may include:

  • Monthly breast self-exams to develop breast familiarity and to detect any unusual breast changes
  • Clinical breast exams every year by a health care provider
  • Screening mammograms every year
  • Consideration of other imaging techniques, such as breast MRI or molecular breast imaging, especially if you have additional risk factors for breast cancer, such as a strong family history of the disease

Preventive therapy

Preventive therapy (chemoprevention) involves taking a medication to reduce your risk of breast cancer.

Preventive therapy options include:

  • Medications that block hormones from attaching to cancer cells. Selective estrogen receptor modulator (SERM) drugs work by blocking estrogen receptors in breast cells so that estrogen isn't able to bind to these receptors. This helps reduce or prevent the development and growth of breast cancers.

    Tamoxifen is one approved for reducing the risk of breast cancer in premenopausal women and postmenopausal women. Raloxifene (Evista) is approved for postmenopausal women to reduce the risk of breast cancer and also to prevent and treat osteoporosis.

  • Medications that stop the body from making estrogen after menopause. Aromatase inhibitors are a class of medicines that reduce the amount of estrogen produced in your body, depriving breast cancer cells of the hormones they need to grow and thrive.

    Aromatase inhibitors anastrozole (Arimidex) and exemestane (Aromasin) are another option for reducing the risk of breast cancer in postmenopausal women. Studies have found these drugs can reduce the risk of breast cancer in women with a high risk, but they aren't approved for that use by the Food and Drug Administration.

Discuss with your doctor the risks and benefits of taking a drug for breast cancer prevention to see if it's the best course of treatment for you. There are pros and cons to the different medications, and your doctor can discuss which drug may be best for you based on your medical history.

You might also consider participating in a clinical trial exploring an emerging therapy for preventing breast cancer. Ask your doctor whether you might be a candidate for current clinical trials.


Surgery may be recommended in certain situations. For instance, surgery is often recommended for a specific type of LCIS called pleomorphic lobular carcinoma in situ (PLCIS). This type of LCIS is thought to carry a greater risk of breast cancer than is the more common classical type.

PLCIS may be detected on a mammogram. If analysis of your biopsy confirms that you have PLCIS, your doctor will recommend surgery. Options may include an operation to remove the area of PLCIS (lumpectomy) or an operation to remove all of the breast tissue (mastectomy). In determining which treatment is best for you, your doctor considers how much of your breast tissue is involved with the PLCIS, the extent of the abnormalities detected on your mammogram, whether you have a strong family history of cancer and your age.

Your doctor may recommend radiation therapy after lumpectomy surgery in certain situations. You may be referred to a doctor who specializes in using radiation to treat cancer (radiation oncologist) to review your specific situation and discuss your options.

Another option for treating LCIS is preventive (prophylactic) mastectomy. This surgery removes both breasts — not just the breast affected with LCIS — to reduce your risk of developing invasive breast cancer. To obtain the best possible protective benefit from this surgery, both breasts are removed, because LCIS increases your risk of developing breast cancer in either breast. This may be an option if you have additional risk factors for breast cancer, such as an inherited gene mutation that increases your risk, or a very strong family history of the disease.

Self care

If you're worried about your risk of breast cancer, take steps to reduce your risk, such as:

  • 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 doctor whether it's OK, and start slowly.
  • Maintain a healthy weight. If your current weight is healthy, work to maintain that weight. If you need to lose weight, ask your doctor about healthy strategies to accomplish this.

    Reduce the number of calories you eat each day, and slowly increase the amount of exercise. Aim to lose weight slowly — about 1 or 2 pounds (about .5 or 1.0 kilograms) a week.

  • Don't smoke. If you smoke, quit. If you've tried to quit in the past, but haven't had success, ask your doctor for help. Medications, counseling and other options are available to help you quit smoking for good.
  • Drink alcohol in moderation, if at all. Limit your alcohol consumption to one drink a day, if you choose to drink.
  • Limit hormone therapy for menopause. If you choose to take hormone therapy for menopause signs and symptoms, limit your use to the lowest dose for the shortest length of time necessary to provide relief.

Coping and support

Although LCIS is not cancer, it can make you worry about your increased risk of a future breast cancer. Coping with your diagnosis means finding a long-term way to manage your fear and uncertainty.

These suggestions may help you cope with a diagnosis of LCIS:

  • Learn enough about LCIS to make decisions about your care. Ask your doctor questions about your diagnosis 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 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 experience some anxiety before your breast cancer screening exams. Don't let this anxiety keep you from going to all of your appointments. Instead, plan ahead and expect that you'll be anxious.

    To cope with your anxiety, 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 that you can feel your best. 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. Find ways to cope with stress in your life.

Preparing for your appointment

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

If you have already had a breast abnormality evaluated by one doctor and are making an appointment for a second opinion, bring your original diagnostic images and biopsy results to your new appointment. These should include your mammography images, ultrasound CD and glass slides from your breast biopsy.

Take these results to your new appointment or request that the office where your first evaluation was performed send the results to your second-opinion doctor.

Here's some information to help you get ready for your appointment, and what to expect from the doctor.

What you can do

  • Write down any symptoms you're experiencing, and for how long. If you have a lump, your doctor will want to know when you first noticed it and whether it seems to have grown.
  • Write down your medical history, including details about prior breast biopsies or benign breast conditions with which you've been diagnosed. Also mention any radiation therapy you have received, even years ago.
  • Note any family history of breast cancer or other type of cancer, especially in a first-degree relative, such as your mother or sister. Your doctor will want to know how old your relative was when he or she was diagnosed, as well as the type of cancer he or she had.
  • Make a list of your medications. Include any prescription or over-the-counter medications you're taking, as well as all vitamins, supplements and herbal remedies. If you're currently taking or have previously taken hormone replacement therapy, share this with your doctor.

What to expect from your doctor

Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over points you want to talk about in-depth. Your doctor may ask:

  • 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 medications 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 the BRCA gene mutations?
  • Have you ever had radiation therapy?
  • What is your typical daily diet, including alcohol intake?
  • Are you physically active?

If your biopsy reveals LCIS, you'll likely have a follow-up appointment with your doctor. Questions you may want to ask your doctor about LCIS include:

  • How much does LCIS 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 medications that reduce the risk of breast cancer?
  • What are the possible side effects or complications of these medications?
  • Which drug 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?

Content From Mayo Clinic Updated: 05/17/2022
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