Invasive Lobular Carcinoma (ILC)

Invasive lobular carcinoma (ILC) is a type of breast cancer that starts in the milk-producing and transportation system of your breast. Healthcare providers may use the term “lobules” or “terminal duct lobular units” when they describe where this cancer starts.

About 10% to 15% of breast cancers are invasive lobular breast cancer. This type of breast cancer usually grows in response to estrogen, the main female hormone. It grows slowly. You may have ILC for years before it’s seen on a mammogram or causes symptoms. Like all other breast cancers, ILC can spread through breast tissue or to other areas of your body.

ILC affects an estimated 31,000 to 46,000 women in the U.S. each year. Early diagnosis and treatment may cure it. But ILC can spread to other areas of your body many years after your diagnosis and treatment.

Invasive lobular carcinoma symptoms

Most of the time, breast cancer happens when cancer cells multiply to create a tumor. The tumor may make a lump in your breast that you can feel. ILC is different. Early on, ILC cells spread out in a single file to form strands or strings of cancer cells.

As ILC grows slowly and may not form a lump, it may not cause noticeable changes in your breasts. When it does, symptoms can include:

• Breast pain or warmth
• Breast skin that looks or feels thicker than usual or has dimples, tiny dents or puckers
• Changes in breast size and shape, like an area of swelling or fullness
• Inverted nipple that points into your breast instead of pointing out
• Lump near your armpit
• Nipple discharge
• Skin discoloration that appears reddish or darker than usual

Invasive lobular cancer causes

ILC happens when genetic mutations (changes) turn healthy cells into cancer cells. Experts aren’t sure what causes the mutations. Researchers believe the following factors increase your risk of having invasive lobular carcinoma:

• Being age 55 and older
• Giving birth after age 30 or not giving birth
• Having had breast cancer previously
• Having a family history of breast cancer or ovarian cancer
• Having lobular carcinoma in situ (LCIS)
• Inheriting certain genetic mutations
• Starting menopause later than usual (after age 55)
• Starting your period earlier than usual (before age 12)
• Receiving certain types of hormone therapy for menopause symptoms

Complications of invasive lobular carcinoma

ILC may cause two unusual complications:

1. It can spread to a larger-than-usual range of organs and tissues.
2. You can develop metastatic invasive lobular carcinoma, which means it spreads to areas of your body far from your breast, 10 to 15 years after your diagnosis and treatment.

Breast cancer that spreads (metastatic breast cancer) typically affects your brain, bones, liver and lungs. ILC may spread to those areas. But it may also spread to less common areas, including your:

• Digestive system, including your colon, small intestine and stomach
• Female reproductive organs, including your ovaries and uterus
• Leptomeninges (the lining of your brain and spinal cord)
• Peritoneum (lining of your abdomen)
• Tissues around your eye (orbital tissues)

How doctors diagnose lobular breast cancer

A healthcare provider will ask about your symptoms. They’ll examine your breasts and the area near your armpits. They may do the following tests:

• Mammogram to look for abnormal masses or changes in your breasts
• Breast MRI to get very detailed images of your breast tissue
• Breast ultrasound to focus on specific areas of your breasts

They may recommend a breast biopsy to get a small sample of your breast tissue. A medical pathologist will examine the tissue under a microscope. They’ll look for abnormal breast cells and other cancer signs.

Your cancer care team will use test results to stage the cancer and plan your treatment. There are four stages of invasive lobular carcinoma:

• Stage I is a tumor that measures up to 2 centimeters (cm) (about 3/4-inch) across and may be in nearby lymph nodes.
• Stage II means the tumor is 2 cm and is spreading to nearby lymph nodes. This stage also includes tumors that measure 5 cm or more (2 inches) across but haven’t spread into lymph nodes.
• Stage III means there’s cancer in your breast and lymph nodes. There are more lymph nodes with cancer than there are if you have stage II cancer.
• Stage IV is cancer that has spread to distant areas of your body, such as your lungs, liver or bones.

Invasive lobular carcinoma treatment

Your treatment may be a combination of:

• Breast cancer surgery
• Chemotherapy before or after surgery
• Hormone therapy if tests show you have estrogen receptor-positive (ER+) breast cancer
• Radiation therapy to kill any cancer cells that may remain after surgery
• Targeted therapy focuses on genetic mutations that turn healthy cells into cancer cells

Recovery time

Your recovery will depend on your treatment. For example, it can take two to four weeks to recover from breast cancer surgery. Recovering from treatments like chemotherapy may take six months to a year. It’s important to understand how cancer treatment may affect your daily routine. Don’t hesitate to ask your oncologists what to expect in terms of recovery.

When should I see my cancer care team?

Contact your cancer care team if you have:

• Surgical wound infection symptoms like a fever (greater than 101 degrees Fahrenheit or 38.4 degrees Celsius) or thick, cloudy discharge from the incision (cut)
• Cancer treatment side effects that are stronger than you expected, like vomiting that you can’t control
• Pain that prescription pain medication doesn’t ease

What is the survival rate for invasive lobular carcinoma?

Cancer survival rates are estimates of the percentage of people with a specific cancer diagnosis who are alive after a certain time — usually one to five years — after they receive a diagnosis.

Research shows that overall, 94% of women with ILC were alive and cancer-free five years after their diagnosis. That estimate includes women who have stage I to stage III when they’re diagnosed. In general, the earlier the stage at diagnosis, the better the prognosis. About 86% of women with ILC are alive and cancer-free 10 years after their diagnosis.

The five-year survival rates for ILC are similar to other types of breast cancer. But they’re 4% to 10% lower at that 10-year mark.

Healthcare providers are working to understand why this is and come up with treatment options to improve your chances of being cancer-free in the long run.

The rates don’t predict how long you’ll live with cancer. Survival rate information can be confusing and cause concern. If you have questions, your oncologist will explain what a survival rate means in your situation.