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The diagnosis of lobular carcinoma in situ (LCIS) can be somewhat confusing. It sounds like a cancer diagnosis, but LCIS is not cancer. It’s a benign condition, but it does increase the risk of developing breast cancer later.

Read on as we discuss:

  • what you need to know about LCIS and breast cancer risk
  • how it’s treated
  • why follow-up screening is so important

LCIS stands for lobular carcinoma in situ.

Lobules are milk-producing glands in the breast. Carcinoma usually refers to cancer, but not in this case. To avoid confusion, some doctors call it lobular neoplasia instead of lobular carcinoma. Neoplasia is abnormal growth. And “in situ” means “in its original place,” meaning it’s not invasive.

It sounds similar, but LCIS is not the same as a type of breast cancer called invasive lobular breast cancer. It’s not a breast cancer at all.

LCIS is a rare condition in which there are abnormal cells in the lining of the lobules, but there’s no invasion of surrounding tissue. It can occur in multiple places in one or both breasts. LCIS does not usually become invasive, but having it increases the risk of developing breast cancer in either breast in the future.

Most of the time there are no symptoms with LCIS. It does not cause discomfort or change in the appearance of the breast, and it seldom causes a noticeable lump.

LCIS is most likely to occur in premenopausal women between 40 and 50 years old. It’s extremely uncommon in men.

LCIS does not always show up on a mammogram or cause symptoms. That’s why it’s usually caught when you have a biopsy for some other reason. A biopsy is the only way to diagnose LCIS.

During a biopsy, the doctor uses a needle to extract a small sample of the suspicious tissue. A pathologist then examines the sample under a microscope to look for abnormal cells or cell overgrowth.

LCIS is not cancer, so active treatment may not be necessary. It’s not life threatening, so you can take your time making treatment decisions. A few factors that can influence these decisions are:

  • the cells are very abnormal (pleomorphic)
  • there are areas of dead cells (necrosis)
  • you have a personal or family history of breast cancer
  • personal preference

Your doctor may recommend removing the abnormal tissue. Surgical options include breast excisional biopsy or breast conserving surgery (lumpectomy) to remove the abnormal area plus a margin of healthy tissue.

Another option is prophylactic mastectomy, which is surgical removal of the breast to lower the risk of breast cancer. It’s not usually recommended for LCIS. Some women who have additional risk factors, such as BRCA gene mutations might be more inclined to choose this surgery.

LCIS increases breast cancer risk in both breasts, so both would be removed. Because there’s no cancer, there’s no need to remove lymph nodes under the armpits (axillary lymph nodes). Removal of the entire breast, including the skin, nipple, and areola, is called simple mastectomy.

You can also choose to have nipple-sparing or skin-sparing mastectomy. If you want to, you can start breast reconstruction surgery immediately following any of these procedures.

Cancer treatments such as chemotherapy and radiation therapy are not needed. If you’re at high risk for breast cancer due to other reasons, your doctor might recommend preventive medicine (chemoprevention) such as tamoxifen or raloxifene.

Be sure to discuss the potential benefits and risks of all options with your doctor.

Follow-up care and reducing risk

LCIS means you’re at higher risk for breast cancer, so it’s important to discuss follow-up screening with your doctor. This may include scheduling regular screenings:

Speak with your doctor if you have new symptoms or notice any changes to your breasts. Warning signs of breast cancer include:

  • a lump
  • change in size or shape of breast
  • inverted nipple, nipple discharge
  • rash, thickening, or dimpling of the skin on the breast
  • swelling under the armpit

In addition to LCIS there are many factors that affect breast cancer risk. If you have a family history of breast or other cancers, ask your doctor if genetic testing is advisable. You might also want to discuss other ways to lower your risk, which may include:

  • regular exercise
  • healthy diet
  • limited alcohol
  • maintaining a moderate weight
  • avoid taking estrogen (hormones)

The prognosis for LCIS is very good.

The risk of developing invasive breast cancer is about 7 to 12 times higher for women who have had LCIS. It’s more likely to happen 10 years or more down the road rather than within the first few years. Even with the increase in risk, most people with LCIS will never develop breast cancer.

A 2017 study model found a favorable 10-year and 20-year breast cancer-specific mortality rate. Most women died from other causes.

For those diagnosed with LCIS at 50 years old, the 20-year breast cancer-specific mortality rate was less than 1 percent. In that group more than 13 percent had died from other causes.

In the cohort diagnosed with LCIS at age 60, the 20-year breast cancer-specific mortality rate was 0.12 to 1.14 percent. In this group, more than 30 percent had died of other causes.

LCIS means there are abnormal cells in the lining of the lobules. While it does increase the risk of developing breast cancer, it rarely becomes cancerous. It’s not cancer and may not need to be treated, though follow-up screening is very important.

DCIS stands for ductal carcinoma in situ. This means abnormal cells have been found within a milk duct, but they have not spread through the wall of the duct. DCIS is stage 0 breast cancer and is sometimes referred to as precancer.

It’s noninvasive but has the potential to become invasive and push through the duct wall and spread beyond. Because there’s no way to determine if it will become invasive or not, DCIS is usually treated, either with lumpectomy or simple mastectomy.

LCIS is a benign breast condition involving abnormal growth of cells. Treatment is not always necessary, but your doctor may recommend removing it. Treatment is tailored to the individual depending on the overall risk of breast cancer and personal preferences.

Although LCIS is not cancer, it does increase the chance you’ll develop breast cancer later. That’s why enhanced screening and risk-reducing measures are so vital. But most women who have LCIS will not develop breast cancer.

Speak with your doctor about your risk factors, what you can do to reduce risk, and any other concerns you might have.