An interior view of breast tissue where some of the lobules are inflamed with tumors

Understanding Invasive Lobular Carcinoma

A diagnosis of breast cancer can bring a lot of different emotions. It can also be challenging since there are many different types and subtypes of breast cancer. These types and subtypes also help determine treatment and prognosis. Learning more about your specific diagnosis can help you understand your diagnosis and help with decision-making.

What is invasive lobular carcinoma?

Most breast cancers are invasive. This means the cancer has spread into surrounding breast tissue. About 1 in 10 invasive breast cancers are invasive lobular carcinoma (ILC). It is the second most common type of breast cancer, after invasive ductal carcinoma (IDC). It can occur at any age but is more common as women age.1-3

ILC starts in the lobules. These are the milk-producing glands of the breast. It can spread past the lobules and invade surrounding tissues. It can also travel through the bloodstream or lymph system to spread (metastasize).2

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ILC may be harder to find on physical exams, and it may not show up in imaging tests like mammograms. Compared to other kinds of invasive breast cancer, about 1 in 5 women may have ILC in both breasts at diagnosis.1,2

How do you know if you have invasive lobular carcinoma?

ILC may not have any symptoms at first. In some cases, an abnormal area may show up on an imaging test. However, ILC is usually harder to see on a mammogram than IDC. This is because instead of forming a lump, IDC cells usually spread in a line formation.4

Sometimes a thickening or hardening is felt, rather than a formed lump.4 Other symptoms can include:4

  • Area of fullness or swelling
  • Change in texture of the skin
  • Nipple turning inward
  • Breast and/or nipple pain
  • Nipple discharge
  • Lump in the underarm area

Diagnosing ILC is done in a variety of ways. With ILC, there is often more than 1 area of cancer in the breast. It is also more likely than other types of breast cancer to be in both breasts, rather than just 1.5 Diagnosing ILC can involve:5

  • Physical exam of the breast and underarm area
  • Mammogram
  • Ultrasound
  • Breast MRI
  • Biopsy

How is invasive lobular carcinoma treated?

Treatment for ILC can vary, depending on the stage of the cancer and any other factors. Generally, it involves surgery and radiation, and/or chemotherapy. Surgery can consist of a lumpectomy or mastectomy, depending on the tumor.6

Radiation and/or chemotherapy may be necessary, especially if the cancer has spread to under the arm or past the breast area.6

Most women with ILC will need to take daily anti-estrogen drug for 5 to 10 years after surgery. This is because many women with ILC will test positive for hormone receptors. Taking the drug will help treat the cancer and reduce the risk of the cancer returning.6

The outlook for invasive lobular carcinoma

There are effective treatments for ILC. Your doctor can talk with you about your specific markers and features of your ILC and what this means for your prognosis. New treatments are being researched all the time. Ask your doctor about any clinical trials for ILC that may be right for you.

This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.

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