Lobular carcinoma in situ (LCIS) 

Lobular carcinoma in situ (LCIS) is an area of abnormal cell growth within the milk glands (known as terminal ductal lobular units). These cells do not invade into other parts of the breast. LCIS is most commonly identified following a breast biopsy after the patient or doctor finds a suspicious lump or after an abnormal mammogram.

The fact that the cancer is contained within the milk lobules and ducts means that lobular carcinoma in situ may be referred to as stage 0 cancer, or pre cancer. This is similar to ductal carcinoma in situ (DCIS). LCIS is different to invasive lobular carcinoma (ILC), which is the term given to cancer cells with a similar growth pattern that have spread beyond the ducts and lobules.

Whilst LCIS is not referred to as cancer, people with LCIS are at a greater risk of developing breast cancer at a later stage in their lives than those who have never had LCIS. The most common type of breast cancer is invasive ductal carcinoma and invasive lobular carcinoma is less common, accounting for around 10-15% of cases of invasive breast cancer. 

Symptoms of Lobular Carcinoma in situ 

LCIS generally does not cause any noticeable signs or symptoms to the breast, and most women are not aware of any symptoms when they are diagnosed.  

Diagnosis for Lobular Carcinoma in situ 

LCIS is most commonly found as a result of a biopsy. This involves taking a small sample of cells or tissue from the area of concern in the breast, which is then examined by a pathologist. 

LCIS Subtypes

As mentioned, there are several subtypes of LCIS and the subtype/s found during a biopsy may affect how your doctor proceeds, with both further testing and management. 

• Classical LCIS
  In classic LCIS, abnormal cells are seen in the lobules of the breast that are small and don’t show variations in size shape. In the absence of markers for any of the other subtypes of LCIS, it is classified as classic LCIS. 
• Pleomorphic LCIS  
  A diagnosis of pleomorphic LCIS is made when the cells look more irregular in shape than classical LCIS, with the presence of ‘high grade’ nuclei (more abnormal than normal breast nuclei and likely more aggressive) when examined under the microscope. PLCIS is rare but may carry a higher risk of developing into invasive cancer than other types of LCIS.
• Florid/bulky (mass forming) LCIS 
  In classic LCIS subtype, the affected duct/lobular tree is distended, forming a mass-like appearance. The cells are usually low/Intermediate grade.  

Treatment for Lobular Carcinoma In Situ 

Lobular carcinoma in situ is not a life-threatening condition. However, due to the increased risk of developing breast cancer later in life, women diagnosed with LCIS are advised to have regular check-ups, including: 

• a physical examination of both breasts by a doctor once a year 
• a mammogram or ultrasound of both breasts once a year

Some hormone therapies have been proven to reduce the risk of developing breast cancer, and this may be recommended for women with LCIS. In addition, depending on the outcome of a biopsy breast surgery may be recommended. It’s important to speak to your doctor about your options.