What is Invasive Lobular Carcinoma?

Invasive (or infiltrating) lobular carcinoma (ILC) is a type of breast cancer that began in the milk-producing lobules, which empty into the ducts that carry milk to the nipple, and has spread into surrounding tissue. It is the second most common type of breast cancer (next to invasive ductal carcinoma), accounting for 10-15% of invasive breast cancers diagnosed in the U.S.

Who is at risk of developing invasive lobular carcinoma?

Anyone can develop ILC, but the risk is much higher for some than others.

• ILC is quite rare in men, accounting for only about 2% of male all breast cancers (which are diagnosed in only 1 in 1000 U.S. men).
• ILC tends to affect women slightly later in life than invasive ductal carcinoma, being most common in the early 60s rather than the mid- to late 50s.
• Some research suggests that the use of hormone replacement therapy (HRT) during and after menopause can increase ILC risk.
• Women who have been diagnosed with lobular carcinoma in situ (LICS) are 8-10 times more likely to develop invasive cancer, and recent evidence suggests that some cases of LCIS may develop into ILC.

What are the symptoms of ILC?

ILC may not produce any noticeable symptoms, which makes regular screening mammograms essential in detecting this form of cancer as early as possible. In some cases, however, patients may experience a thickening or hardening in the breast (as opposed to a distinct lump), an area of swelling or fullness, irritation or dimpling of the skin on the breast, or the inversion of a nipple.

How is ILC diagnosed?

Initially, your physician may notice one or more of the above symptoms during a physical breast exam and follow up with imaging, or the radiologist may spot an abnormal area on your mammogram and order further testing to identify it. Because of its unusual growth pattern, ILC can be difficult to identify on a mammogram. Rather than forming a lump, ILC cells tend to invade surrounding tissue in a line. As a result, a breast ultrasound or breast MRI may be ordered to get a better look at the area of concern. Suspicious imaging results will typically be followed up with biopsy to more precisely determine the nature of the abnormality.

How is ILC treated?

Surgery

The course of ILC treatment will vary from patient to patient depending on the location(s) and extent of the cancer. At minimum, surgery will be performed to remove the cancer and, often, one or more lymph nodes for examination.

• A lumpectomy removes only the tumor and a small amount of surrounding normal tissue. This may be sufficient for treating small, contained tumors.
• A mastectomy (removal of the breast) can be performed on different levels, depending on the extent of infiltration.
  • In a partial mastectomy, the surgeon removes the portion of the breast that contains the tumor.
  • A total or simple mastectomy is removal of the entire breast, leaving the muscle intact.
  • A radical mastectomy used to commonly involve removal of all of the muscle beneath the breast; however, a modified version, in which only the lining of this muscle is removed, is more widely practiced today.

Radiation Therapy

After surgery, radiation may be used to treat the area where the tumor was, destroying any cancer cells that may have been left behind and reducing the risk of recurrence. Radiation is frequently used following surgeries that conserve healthy breast tissue or after mastectomies that remove large tumors and/or involved lymph nodes.

Systemic Therapies

Chemotherapy is often recommended for patients with invasive lobular carcinoma. If the mass is large or has spread to many lymph nodes, then chemotherapy may be prescribed to shrink the cancer prior to surgery. A course of chemotherapy typically takes 3 to 6 months.

Hormone therapy is used in patients with cancer that is hormone-receptor positive. When a cancer has hormone receptors, estrogen and/or progesterone signal the cancer cells to divide, fueling growth of the tumor. Hormone therapy works by either reducing hormone levels in the body or by interfering with their ability to communicate to receptors.

Other systemic therapies can be used to target growth mechanisms specific to particular varieties of cancer. Researchers are actively working to find more ways to interfere with cancer’s ability to grow and proliferate.

Iowa Radiology provides a range of state-of-the-art breast imaging services, including low-dose 3-D mammography, breast ultrasound, and breast MRI. We strive to make all our patients as comfortable as possible and answer any questions that we can. Click here to request your screening mammogram at our Clive, Ankeny, or downtown Des Moines clinic. If you have questions about mammography, download our free eBook by simply clicking below. It contains valuable information such as what to expect, how to prepare, potential follow-up, and the added benefits of 3-D mammograms.

The information contained in the Iowa Radiology website is presented as public service information only. It is not intended to be nor is it a substitute for professional medical advice. You should always seek the advice of your physician or other qualified healthcare provider if you think you may have a medical problem before starting any new treatment, or if you have any questions regarding your medical condition. Iowa Radiology occasionally supplies links to other web sites as a service to its readers and is not in any way responsible for information provided by other organizations.

Sources

"Breast cancer in men." Cancer.org. American Cancer Society, n.d. Web. 17 Dec 2015.

"ILC -- Invasive Lobular Carcinoma." BreastCancer.org. Breastcancer.org, n.d. Web. 17 Dec 2015.

"Invasive Lobular Carcinoma (ILC)." HopkinsMedicine.org. The Johns Hopkins University, n.d. Web. 17 Dec 2015.

"Lobular Carcinoma in Situ (LCIS)." Komen.org. Susan G. Komen, 23 Sept 2015. Web. 17 Dec 2015.

Roth. "Lobular Breast Cancer: What Are the Prognosis and Survival Rates?" Healthline.com. Healthline Networks, Inc., 27 Aug 2014. Web. 17 Dec 2015.