Lobular carcinoma in situ (LCIS) means that abnormal cells have formed in the milk glands (lobules) in the breast. Generally, LCIS is considered by clinicians to be a non-cancerous (benign) breast condition, however, it is linked to a higher risk of invasive breast cancer later in life.
LCIS is an uncommon condition where abnormal cells that look like cancer cells are contained within the inner lining of the lobules in the breast, yet they don’t invade through the wall of the lobules. The lobules are glands that make breast milk and are located in clusters (like a bunch of grapes) at the end of the milk ducts in the breast.
It is important to note that LCIS is not considered by clinician groups to be “breast cancer”. It is considered a breast change and may be found in both breasts.
Along with another type of breast change called atypical lobular hyperplasia, LCIS is a type of “lobular neoplasia”. They are benign (non-cancerous) conditions, but both increase your risk of breast cancer. Most women with LCIS will not get breast cancer. Men can develop LCIS, but this is very rare.
Generally, LCIS doesn’t normally cause symptoms and cannot usually be felt as a breast lump or show up on a mammogram. It is often found by chance during tests for other breast conditions such as a biopsy.
If LCIS is found by a biopsy your specialist may recommend removing more breast tissue from the area to check if there are any cancer cells in that part of the breast. This may involve a core biopsy using a needle to take tissue samples or an excision biopsy where a sample of tissue is removed via an operation. A mammogram and ultrasound may also be used to locate the area. Talk to your doctor about the tests you might have and what they involve.
Most people with LCIS have the "classic" type, which means that the abnormal cells lining the lobules are small and similar in size. Breast cancer is unlikely to develop from these classic LCIS cells, and therefore you may not need to have any treatment.
If there are no other abnormal changes in the breast, LCIS does not usually require treatment. This is because LCIS is confined inside the breast lobule, and – even without treatment – it does not usually spread beyond the lobule and become invasive breast cancer. People with LCIS have a very good prognosis, and the evidence shows that LCIS does not need to be surgically removed or treated in other ways to maintain that good prognosis.
Lobular carcinoma in situ (LCIS) is not life-threatening. However, having LCIS means that you may have an increased chance of developing breast cancer in the future. Your doctor will likely recommend that you have regular monitoring, which may include more frequent physical examinations and screening for signs of breast cancer.
You may be recommended surgery if you have the type of LCIS called either “pleomorphic” or “florid” LCIS. This is because the risk of breast cancer is higher with these types of LCIS. In pleomorphic LCIS, the cells are larger and look more abnormal than classic LCIS. In florid LCIS, the cells have formed a mass with an area of dead cells in the middle (necrosis). Pleomorphic and florid LCIS may be detected on a mammogram.
In some cases, breast conserving surgery (lumpectomy), mastectomy or preventative medication (e.g. hormone-blocking therapy) may be recommended to reduce the risk of invasive breast cancer developing in the future. Your doctor will talk to you about the best options for your individual situation.
A diagnosis of LCIS can raise many different emotions. Fear, shock and anxiety are common. Although LCIS is not breast cancer, you may feel anxious and worried about your risk of breast cancer in the future.
It is important to talk to your treating team about any concerns you may have.
If you have LCIS you may consider participating in a clinical trial exploring new treatments for preventing breast cancer. Ask your doctor whether you might be suitable for a clinical trial.
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*This article does not provide medical advice and is intended for informational purposes only.
Please consult a medical professional or healthcare provider if you're seeking medical advice, diagnoses, or treatment.