Invasive Lobular Carcinoma

What is invasive lobular carcinoma?

Invasive lobular carcinoma (ILC) is sometimes referred to as infiltrating lobular carcinoma and is the second most common type of breast cancer after invasive ductal carcinoma (IDC). About 10% of invasive breast cancers are invasive lobular carcinomas. ILC is cancer that originates in the lobules, which are the milk producing glands of the breast, and spreads to surrounding tissues. If untreated, ILC can spread to the lymph nodes and other body parts.

There are different subtypes of ILC:

Classic Invasive Lobular Carcinoma:

Cancer cells invade the stroma, the fatty tissue and ligaments around the milk ducts and lobules, in a single-file formation, and cells look uniform and identical under the microscope.

Solid Invasive Lobular Carcinoma:

Cancer cells grow in large sheets with little stroma.

Alveolar Invasive Lobular Carcinoma:

Cancer grows in groups of 20 or more cells

Tubulolobular Invasive Lobular Carcinoma:

There is some single-file cancer cell formation similar to classic ILC, but there are also some tubule cell structures.

Pleomorphic Invasive Lobular Carcinoma:

Unlike classic ILC, these cancer cells have irregular nuclei and are larger in size.

Signet Ring Invasive Lobular Carcinoma:

Within these cancer cells, the nuclei have been pushed off-center due to a surplus of mucus within the cell.

What are the signs and symptoms of ILC?

It's very common for invasive lobular carcinoma to present without any signs or symptoms. This is why it's important for women over 40 to get annual screening mammograms. Many cases of ILC are diagnosed not through symptoms but from abnormal cells spotted on screening mammograms. Although symptoms are not always present, the following signs are indicative of breast cancer:

  • Breast swelling or tenderness
  • Breast or nipple pain
  • Irritation of the breast skin or nipple
  • Lump in underarm
  • Irregular nipple discharge

If you are experiencing any of these symptoms, or you have any breast cancer risk factors, you should contact your physician.

How is invasive lobular carcinoma diagnosed?

After discovering an abnormality on a physical exam or a routine screening mammogram, your physician will likely proceed with more advanced mammogram imaging. If the abnormality is still present on the new mammogram images, then your physician will proceed with additional testing:

  • Ultrasound Imaging
  • Breast MRI
  • Biopsy
    • Fine needle aspiration biopsy
    • Core needle aspiration biopsy
    • Incisional biopsy
    • Excisional biopsy

After your physician has made the diagnosis of ILC, they will need to stage your cancer. What stage of cancer you have (stage I through IV) depends on the size of the tumor and whether or not it has spread into lymph nodes or other body parts. If your physician is concerned that your cancer has spread they will order additional testing to see which parts of the body have been affected:

  • Alkaline phosphatase (also known as an ALP or a blood test)
  • Bone scan
  • CT, Ultrasound, or MRI imaging
  • PET/CT scan

ILC is generally slow to spread to other parts of the body, but if it does spread, it tends to infiltrate the stomach, intestines, abdomen lining, reproductive organs, and the tissue covering the brain and spinal cord.

How is ILC treated at Baptist?

At Baptist, our physicians will create a personalized treatment plan based on each patient's unique diagnosis, lifestyle, and any medical limitations. Depending on if your ILC has spread to another part of your body, you will receive either local or systemic ILC treatment.

Local ILC Treatment

If your cancer has not spread to other body parts, your physician will likely pursue a local ILC treatment plan, which may include both surgery and radiation therapy. Depending on the stage and subtype of your ILC, your physician may also treat your lymph nodes as part of your treatment plan.

IDC Surgical Options

  • Lumpectomy
  • Mastectomy (partial, simple, or modified radical mastectomies)
  • Sentinel lymph node dissection*
  • Axillary lymph node dissection**

Radiation Therapy Treatment Options

  • External beam radiation
  • Internal partial-breast irradiation
  • External partial-breast irradiation

Systemic ILC Treatment

If your physician is pursuing a systemic IDC treatment plan, this plan generally will include chemotherapy, hormone therapy, and possibly some targeted therapies too. This will treat the whole body for cancer and not just the breast tissue.

Chemotherapy treatment involves taking anti-cancer medication via an injection or orally as a pill. Chemo treatment usually uses more than one drug to damage the cancerous cells. Prior to recommending chemo, you physician might run some genomic assays, which are tests to see the likelihood of recurrence. If your tests come back with a high risk of recurrence then your physician will probably recommend chemotherapy as part of your treatment plan.

If your IDC tested positive for hormone receptors, then your physician will likely recommend hormone therapy. During hormone therapy, certain medications will be used to lower the amount of estrogen and progesterone in your body using hormone blockers.

*In sentinel lymph node dissection, the surgeon will locate the sentinel (first) lymph node. Since this is the most likely lymph node to be affected by IDC, the surgeon removes this and the closest lymph nodes for analysis by a pathologist to determine if the cancer has spread.

**Axillary lymph node dissection is the removal of a group of lymph nodes under the arm. This procedure differs from sentinel lymph node dissection because there is a greater risk for developing lymphedema, swelling caused by the buildup of lymph fluid.