Lobular Breast Cancer
What is lobular breast cancer?
Lobular breast cancer (also called invasive lobular carcinoma) is a type of breast cancer that begins in the milk-producing glands (lobules) of the breast. It is the second most common type of breast cancer, accounting for about 10% to 15% of all invasive breast cancers. Cancer of the breast ducts (called invasive ductal carcinoma) is the most common type of invasive breast cancer, accounting for 65% to 85% of all invasive breast cancers.
What does “invasive” lobular breast cancer mean?
Invasive means that the cancer has invaded or spread from its original contained location – in this case, from within the walls of the lobule -- into the surrounding breast tissue. Over time, invasive lobular breast cancer can also spread to the lymph nodes in the underarms, beneath the breast or inside the chest or to other areas in the body away from the breast.
What is the difference between breast lobules and breast ducts?
Lobules are the milk-producing glands of the breast. Breast ducts are the thin tubes that carry breast milk from the lobules of the breast to the nipple.
How is lobular breast cancer different from other breast cancers?
Compared to other types of breast cancer, lobular breast cancer:
- Has different symptoms than other more common types of breast cancer.
- May be harder to see on mammogram because it does not cause a firm or distinct lump.
- May not be diagnosed until the cancer is large enough to cause symptoms.
- Is more likely to involve both breasts.
- Can reoccur many years after the first diagnosis and cancer can spread to different-than-typical sites like the stomach, intestine, ovary, kidneys, ureters and eye.
Who is more likely to develop lobular breast cancer?
Risk factors for developing lobular breast cancer are the same as those for developing breast cancer in general. These include:
- Older age. The risk of breast cancer increases with age. Most breast cancers are diagnosed after age 50.
- Being diagnosed with lobular carcinoma in situ. This means you have abnormal cells confined within the lobules of your breast. Although this is not considered cancer, it does increase your risk of developing breast cancer.
- Family history of breast cancer. Having a mother, sister, or daughter (a "first-degree relative") who has had breast cancer.
- Early puberty/late menopause. Starting your period at an early age (before age 12) or experiencing late menopause (after age 55).
- Not having children/later childbirth. Not having children or having your first child after the age of 35.
- Postmenopausal hormone use. Using the female hormones estrogen and progesterone for more than 5 years to manage menopause symptoms.
- Exposure to radiation. Receiving radiation to the breast or chest to treat cancer before the age of 30.
- Having genetic mutations for certain types of breast cancer. Being a carrier of the familial breast cancer genes, BRCA1 and BRCA2.
- Being overweight.
- Drinking alcohol. Compared with nondrinkers, women who consume one alcoholic drink a day have a 10% increase in risk. The risk increases the more you drink.
Symptoms and Causes
What causes lobular breast cancer?
The life cycle of normal cells is to grow, divide and die. Cancer cells do not follow this normal life cycle. Technically, the definition of cancer is uncontrollable cell growth. The cause of this uncontrollable cell growth is a mutation (change) in the DNA (“the blueprint”) of cells. The cause of the DNA mutation is not always clear to scientists.
The growth of breast cancer cells is fueled by estrogen and/or progesterone, which are female hormones produced in the body. Most types of breast cancers are usually estrogen positive, which mean they grow in response to estrogen. Your doctor may prescribe medications to block the effects of estrogen to help prevent the return of cancer after your initial treatment.
What are signs and symptoms of lobular breast cancer? How does the breast tissue feel?
There may not be any obvious signs of lobular breast cancer at first. Unlike more common breast cancers, lobular breast cancer is less likely to form into a lump in the breast tissue or under the arm. Instead, you may feel a fullness, thickening or swelling in one area that feels different from the surrounding area. Nipple flattening or inversion (pointing into the breast instead of out) can also be a sign of lobular breast cancer.
Diagnosis and Tests
How is lobular breast cancer diagnosed?
Your doctor will likely order a mammogram and ultrasound to look for abnormal breast tissue. A breast MRI scan is a more sensitive test for detecting breast cancer. Your doctor may order this test if you are at higher risk of breast cancer or if mammogram or ultrasound findings raise concerns that should be investigated further.
If abnormal breast tissue is seen on breast imaging, a small sample of tissue is taken from the area of concern using a needle (a procedure called a needle biopsy) and examined under a microscope. The results of the biopsy either confirm or rule out a diagnosis of breast cancer.
Management and Treatment
How is lobular breast cancer treated?
Once a lobular breast cancer is found, treatment consists of surgery followed by radiation and/or chemotherapy. Depending on the size of the tumor, surgical options include removing the tumor and some normal tissue around it (lumpectomy) or a part of or the whole breast (mastectomy) including some lymph nodes and muscle tissue. If a breast MRI was not done before, it may be done prior to surgery to make sure the planned surgery will be able to remove all the cancer.
Following surgery, you may need radiation therapy to kill any cancer cells left at the site of the tumor and/or chemotherapy to kill cancer that may have spread to the lymph nodes under the arm and beyond the breast area.
Most patients will need to take daily doses of anti-estrogen medications for 5 to 10 years after surgery to continue to treat the cancer. These medications include tamoxifen (Evista®) and aromatase inhibitors, such as letrozole (Femara®), exemestane (Aromasin®) and anastrozole (Arimidex®).
What should I do if I’m concerned about lobular breast cancer or any other types of breast cancers?
Since it is difficult to diagnosis lobular breast cancer, the best advice is to see your doctor as recommended for your breast exam and breast cancer screening exams. If you notice any signs or symptoms of lobular breast cancer, make an appointment to see your doctor as soon as possible.
Cleveland Clinic’s comprehensive Breast Cancer Program hosted the patient learning event, Lobular Breast Cancer: An Evening of Learning, on August 22, 2019. This two hour program featured a panel of lobular breast cancer experts and Cleveland Clinic physicians who answered patients questions about lobular breast cancer, and discussed differences in this subtype, how treatment and surveillance have changed with research and future research efforts underway. Watch the panel discussion.