Key Points about Lobular Carcinoma in Situ (LCIS)

  • Lobular carcinoma in situ (LCIS) is a condition that leads to an increased risk of developing breast cancer.
  • LCIS typically does not cause any symptoms.
  • People with LCIS are closely monitored and routinely tested for breast cancer so that it can be diagnosed and treated early if it develops.


Breast cancer is cancer that begins in the breast tissue. Lobular carcinoma in situ – or LCIS – is a rare condition in which abnormal cells form in the breast's milk glands (lobules). It’s important to note that LCIS is not cancer but rather a condition that puts you at an increased risk of developing breast cancer. Of all women who have LCIS, about 20 percent will be diagnosed with breast cancer at some point in their life.

Lobular carcinoma in situ causes

LCIS is caused by mutations (changes) to the DNA of the cells of the milk glands of the breast.

Lobular carcinoma in situ risk factors

The following factors may increase your risk for having LCIS:

  • Being over the age of 40
  • Having a family history of breast cancer
  • Using estrogen-progestin combination hormone therapy for more than three years after menopause

Lobular carcinoma in situ symptoms

LCIS does not cause any symptoms. The condition is typically diagnosed during testing for another issue, such as a breast lump or an abnormal finding in a mammogram.

Lobular carcinoma in situ diagnosis

In almost all cases, LCIS is not visible on a mammogram (specialized breast imaging test) or other imaging tests. Most doctors discover LCIS while performing a biopsy for another concern. In this test, your doctor removes a biopsy (small tissue sample) from a suspicious area. This sample is sent to the laboratory, where a specialist closely checks the biopsy for abnormalities. If LCIS is present, it will be discovered during the lab analysis.

Lobular carcinoma in situ treatments

Depending on your personal health history, the extent of your lobular carcinoma in situ and other factors, your oncologist may recommend one or more of the following treatment options:

  • Ongoing monitoring - if you are diagnosed with LCIS, you have an increased risk of developing breast cancer. Therefore, your doctor may recommend a close testing and monitoring plan to continue to check for cancer.
  • Preventative chemotherapy - your doctor may recommend that you undergo preventive chemotherapy, which may help reduce your risk of developing breast cancer in the future. During this treatment, medication is used to destroy cancerous cells. Chemotherapy can be taken via an oral (by mouth) pill or intravenously (through a vein).
  • Surgery - you may need to undergo surgery to remove the breast tissue affected with LCIS. Your surgeon will work to preserve as much surrounding healthy tissue as possible. In some cases, you may opt to undergo reconstructive surgery following surgery.

When should I seek care?

If you experience any of these symptoms, start by voicing your concerns and symptoms to your primary care provider. From there, your doctor may suggest seeing an oncologist for more specialized treatment.

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