Invasive lobular carcinoma
Invasive lobular carcinoma (ILC) is a breast cancer affecting 180,000 new patients each year. About 10 percent of all breast cancers are this type, making ILC the second most common form of the disease. Invasive lobular carcinoma is a cancer beginning in a part of the milk-producing glands, called lobules, that has broken through walls of the glands and spread to surrounding breast tissue. This form of cancer often spreads to lymph nodes and throughout the rest of the body.
Definition & Facts
Invasive lobular carcinoma is second in frequency to invasive ductal carcinoma (IDC), breast cancer starting in the milk ducts. ILC originates in milk-producing glands that push milk into the ducts for passage to the nipple. IDC affects 80 percent of women with breast cancer, whereas only 10 percent of women diagnosed with breast cancer have ILC.
Women of any age can be diagnosed with invasive lobular carcinoma. But older women are more frequently diagnosed with this form of breast cancer. The American Cancer Society has determined that about two-thirds of women diagnosed with invasive breast cancer are over the age of 54, with ILC seen most often in women diagnosed in their early 60s.
Hormone replacement therapy used during and after menopause is suggested by research to increase the risk of ILC. Invasive lobular carcinoma is unlike other breast cancers, in that it does not typically form a lump in the breast. Instead, the breast feels fuller or thicker in areas of the breast and in comparison to other breast tissue.
Symptoms & Complaints
Thickening or a fuller feeling in breast tissue is often one of the first signs of changes as a result of invasive lobular carcinoma. The nipple also sometimes inverts in early stages. Breast cancers, including invasive lobular carcinoma, often lead to the following symptoms:
- Breast swelling
- Dimpling or irritation of skin on the breast
- Pain in the breast
- Nipple pain
- Scaliness, redness, or thickening of breast skin or the nipple
- Non-milk nipple discharge
- Underarm lump
Doctors do not know what causes invasive lobular carcinoma. Some research indicates that hormone replacement therapy during and after menopause increases likelihood of ILC. Doctors do know that ILC starts when cells in milk producing lobules develop DNA mutations. From that point, cell growth is uncontrolled.
Cells divide and grow rapidly, often spreading to other parts of the body. Invasive lobular carcinoma can invade surrounding tissue of the breast in a star-like formation. The affected breast tissue starts to feel different than other tissue around it, but lumps are unlikely to manifest. Risk factors for invasive lobular carcinoma include:
- Being female
- Age over 54
- Prior diagnosis with lobular carcinoma in situ (LCIS), abnormality of cells in breast glands
- Use of hormone replacement therapy after menopause, particularly estrogen and progesterone
- Inherited genetic cancer syndromes
- Inherited genes indicating greater risk of breast and ovarian cancers
Diagnosis & Tests
To diagnose invasive lobular carcinoma, testing may include:
- Mammogram, although it is more difficult to see ILC on these tests than other forms of breast cancer
- Ultrasound of the breast
- Magnetic resonance imaging (MRI)
- Tissue biopsies for lab testing
Once invasive lobular carcinoma has been found, the doctor must determine the extent of this invasive cancer in the body. Additional imaging tests, blood tests and physical examinations can lead to accurate conclusions regarding the cancer stage. CT scans may be ordered to help with this stage determination in some cases.
Treatment & Therapy
Treatment for invasive lobular carcinoma depends upon the cancer's stage and aggressiveness. Overall patient health and personal preferences also help determine the treatment path. Surgery may be required and other therapies often accompany this surgery. Surgery for invasive lobular carcinoma may include removal of the following tissues:
- Cancerous tissue and portions of surrounding healthy tissue, also known as a lumpectomy
- All breast tissue, called a mastectomy
- All breast tissue, nipple, areola and lymph nodes in the armpit, called a modified radical mastectomy. Radical mastectomies remove all of those tissues as well as the major muscles underneath the breast.
- Lymph nodes nearest the cancer, a sentinel lymph node biopsy
- Additional lymph nodes when cancer has invaded sentinel nodes, called an axillary lymph node dissection
- Uses drugs to kill cancer cells
- May involve combining multiple cancer drugs
- Can be administered through a vein, in a pill or using both means of delivery
- Is commonly used after surgery to kill any remaining cancer cells
- May be used prior to surgery to shrink large tumors
- Uses high powered energy beams to kill cancer cells
- Involves the patient lying on a table while the machine moves around the body, directing beams at the affected breast tissue
- May be used after lumpectomy
- May be used after mastectomy if cancer was in the lymph nodes or impacted a large area
Hormone therapy is another option for treatment if the cancer cells show sensitivity to hormones. Invasive lobular carcinomas are often sensitive to hormones. For this therapy, tumor cells are sampled and tested to determine whether hormone sensitivity exists. As part of these therapies, hormones may be utilized to block natural hormone production or block the cancer cells' ability to use hormones.
Prevention & Prophylaxis
Up to 10 percent of breast cancer in Americans is linked to inherited genetic mutations. The best known genetic mutations linked to breast cancer, BRCA1 and BRCA2 can indicate an individual's increased risk of breast and ovarian cancer. Many patients are using genetic testing to test for the BRCA mutation in order to gain an understanding of their potential for developing breast cancer. The results of genetic testing can enable people to make informed decisions about medical examinations and frequency of imaging and other tests.