Invasive lobular carcinoma (ILC)

Invasive lobular carcinoma (ILC) is a type of breast cancer that begins in the milk-producing glands and has spread to other parts of the body. ILC is the second most common form of breast cancer, accounting for 10-15% of all cases.

If you’re diagnosed with ILC, our cancer specialists at Advocate Cancer Institute are here for you. From genetic testing to access to clinical trials, we offer the most comprehensive cancer care in Illinois.

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Risk factors for invasive lobular carcinoma

Some risk factors associated with invasive lobular carcinoma include:

• Age: The risk of ILC is more common in women over the age of 55.
• Family history and genetics: Having a family history of breast cancer, particularly in a mother, sister or daughter can increase the risk.
• Personal history of breast cancer: Having breast cancer in one breast increases the risk of developing it in the other breast or developing a new cancer in the same breast.
• Hormone replacement therapy (HRT): ;Long-term use of hormone replacement therapy can increase the risk of breast cancer, including ILC.
• Reproductive factors: Factors related to reproductive history such as early menstruation (before age 12), late menopause (after age 55), having the first child at an older age or never having children may increase the risk.
• Dense breast tissue: Having dense breast tissue makes it harder to detect cancers on mammograms and may be associated with a higher risk of breast cancer.
• Certain benign breast conditions: Some benign breast conditions such as lobular carcinoma in situ (LCIS) or atypical hyperplasia may increase the risk of developing invasive breast cancer, including ILC.

Having one or more risk factors doesn't necessarily mean you'll develop ILC, and many people with breast cancer have no identifiable risk factors. Regular breast screenings and early detection are vital for improving outcomes.

Invasive lobular carcinoma symptoms

Invasive lobular carcinoma likely won’t have symptoms. However, there are a few signs that could indicate a problem, such as:

• Thickening or hardening of breast tissue
• Changes in breast shape or size
• Breast pain or discomfort
• Nipple changes
• Nipple discharge
• Swelling of the breast or arm

If you notice any persistent changes in your breast health or experience any of the symptoms mentioned above, schedule an appointment with your doctor for further evaluation.

What is the most invasive type of breast cancer?

The most invasive type of breast cancer is considered inflammatory breast cancer (IBC). Unlike other types of breast cancer, inflammatory breast cancer typically does not present as a distinct lump or mass.

Instead, it often shows signs such as redness, swelling, warmth and a thickening of the skin on the breast. The affected breast may also appear larger, firmer or more bruised compared to the other breast.

Inflammatory breast cancer is called "inflammatory" because the breast often appears inflamed due to the infiltration of cancer cells into the skin and lymph nodes of the breast. It tends to grow and spread rapidly, making it one of the most aggressive and rare forms of breast cancer.

What is an invasive lobular carcinoma grade?

Invasive lobular carcinoma grade refers to a system used to classify the characteristics of cancer cells under a microscope. The grading system helps predict how quickly cancer may grow and spread.

Understanding the grading system

• Grade 1 (low grade): Cancer cells closely resemble normal breast tissue cells. They tend to grow and spread slowly, making this grade of IBC less aggressive.
• Grade 2 (intermediate grade): Cancer cells display some abnormal characteristics but are not as different from normal cells. They may grow and spread at a moderate rate.
• Grade 3 (high grade): Cancer cells appear significantly different from normal cells. They are more aggressive, tend to grow and spread rapidly, and have a poorer prognosis.

ILC is considered low to intermediate grade. This means that it tends to have well-formed lumps and a low to moderate growth rate.

Diagnosing invasive lobular carcinoma

Invasive lobular carcinoma may be diagnosed through a combination of methods, including an examination, imaging studies and tissue biopsy.

The diagnosing process will start with a physical exam of the breasts and surrounding lymph nodes to check for lumps, thickening or changes in appearance.

Imaging tests are often used to detect and evaluate breast abnormalities. Mammograms are typically the first screening for breast cancer. However, ILC may be more challenging to detect on mammograms compared to invasive ductal carcinoma due to its diffused growth pattern.

Additional digital imaging tests, such as breast ultrasound or MRI, may be used to check any suspicious areas.

Biopsies for diagnosing invasive lobular carcinoma

If imaging studies detect abnormalities in the breast, a biopsy is necessary to confirm or deny the diagnosis of invasive lobular carcinoma. During this procedure, a small sample of tissue is extracted from the breast, either through a thin needle or during a surgical intervention.

The tissue sample is then examined under a microscope by a pathologist to confirm the presence of cancer cells and examine the characteristics of the cells.

Upon confirmation of a diagnosis of ILC, further tests may be ordered by your doctor to evaluate the stage of your cancer and whether it has spread to other parts of your body.

Treatment for invasive lobular carcinoma

Typically, invasive lobular carcinoma treatment involves a combination of surgery, radiation therapy, systemic therapy (such as chemotherapy, hormone therapy and targeted therapy) and other treatments depending on the characteristics of the cancer and your general health.

Possible ILC treatments may include:

• Surgery: Surgical options include a lumpectomy (breast conserving surgery) or a mastectomy, which involves the partial or full removal of the breast tissue. If you have a lumpectomy, your doctor will give you radiation therapy to kill any remaining cancer cells in your breast and reduce the risk of it returning.
• Chemotherapy: Chemotherapy may be recommended if the cancer has spread to nearby tissue. It may be administered before or after surgery to shrink the tumor, reduce the risk of recurrence or treat cancer that has spread to other parts of the body.
• Hormone therapy: Hormone therapy, also known as endocrine therapy, is often used for ILC that is hormone-receptor positive, meaning the cells have receptors that bind to estrogen and progesterone that allow them to grow. Hormone therapy works by blocking the effects of estrogen or reducing estrogen levels in the body.
• Targeted therapy: Targeted therapy drugs specifically target certain molecules or pathways involved in cancer growth and progression.

Your care team at Advocate Health Care will use a collaborative approach to provide the best treatment possible. Additionally, supportive care services such as counseling, nutrition therapy, palliative care and physical therapy may be offered to help you manage the physical and emotional challenges of cancer treatment.

What is the hardest form of breast cancer to treat?

The hardest type of breast cancer to treat is triple-negative breast cancer (TNBC). TNBC is characterized by the absence of hormone receptors, making it less responsive to hormone-targeted therapies. Triple-negative breast cancer tends to be more aggressive, with a higher risk of recurrence and poorer prognosis compared to other types of breast cancer.

Similarly, inflammatory breast cancer is another challenging type of breast cancer to treat. Inflammatory breast cancer is aggressive, tends to grow and spread rapidly and often isn’t caught until it’s already at an advanced stage, thus making it less responsive to normal treatments.