Lobular Breast Cancer
Breast cancer is not just one disease. It is many diseases that can form in different parts of the breast and that require different treatments. One way that doctors describe breast cancer is by where in the breast it forms.
Most breast cancers form in the ducts, the tubes that move milk to the nipple. But in lobular breast cancer, the disease forms in the lobules, the glands that make milk. If cancer stays within the lobules, it is called lobular carcinoma in situ (LCIS). If it spreads beyond the lobules into nearby breast tissue, it becomes invasive lobular carcinoma (ILC).
About 10 percent of invasive breast cancers begin in the lobules. Like other breast cancers, lobular breast cancer is most common in women 55 and older. But it can also form in younger women. So far, doctors don’t know of any risk factors that make breast cancer more likely to be lobular than ductal.
Lumps are a classic symptom of ductal breast cancer, but lobular breast cancer may not form a lump until it reaches a larger size. Symptoms of ILC may include feeling that your breasts are heavier or tighter than usual, swelling or other changes to the skin on your breast such as dimpling or stretching, or your nipple becoming inverted.
Lobular breast cancer may be difficult to detect on mammograms, sonograms and even MRIs. Sometimes lobular cancer is not found until it is noticeable during a physical examination. For this reason, it is sometimes found at a later stage than ductal breast cancer. But this does not always mean a worse prognosis. Stage and size of the tumor are not the only factors that affect the outcome of cancer treatment.
But it is still very important to have annual mammograms and other imaging if needed. Be sure you see your doctor if you notice anything unusual about your breast. To confirm you have lobular breast cancer, your doctor will have to do a biopsy.
Once a biopsy confirms the cancer is ILC, it is assigned a stage (I, II, III or IV) in the same way as ductal breast cancer, based on factors like size, and whether cancer cells are in the lymph nodes. Your doctor will also determine whether it grows because of the hormones estrogen or progesterone (hormone receptor-positive) the protein HER2 (HER2-positive) or neither (triple-negative).
Like any form of breast cancer, lobular breast cancer is treated based on its stage and the biologic characteristics of the tumor cells. Surgery, radiation therapy and anti-estrogen hormonal therapy are the most common treatments for lobular cancers. Sometimes doctors recommend chemotherapy. Compared to ductal cancers, lobular breast cancer is more likely to
- Be hormone receptor-positive and HER2-negative
- Be diagnosed in both breasts rather than one
- Grow slowly. This means it may not be as responsive to chemotherapy since chemotherapy targets fast growing cells.
ILC is also more likely than ductal breast cancer to be found in multiple places in the breast, rather than contained in one area of a breast. For this reason, mastectomy may be recommended rather than lumpectomy.
If ILC becomes metastatic, it is more likely to spread to the lymph nodes, lining of the lungs or abdominal cavities or organs such as the stomach or intestines, skin or the reproductive organs. Lobular cancers can also spread to the bones and bone marrow.
Though lobular breast cancer is somewhat less common than ductal breast cancer, it is not rare. Breast cancer surgeons and oncologists are knowledgeable about the condition and how to treat it. You don’t need to look for a doctor who specializes in lobular breast cancer.
Lobular carcinoma in situ (LCIS) is a form of pre-cancer. It increases the risk of invasive lobular or ductal breast cancer, or of ductal carcinoma in situ, DCIS. In LCIS, the cancer cells are found inside the lobules, but haven’t invaded other breast tissue. You can find more information about LCIS and DCIS and how they are treated here.