Breast cancer commonly occurs in the lobules or milk glands and the ducts of the breast. However, it may also form in the nipples or in the underarms. There are two main types of breast cancer—invasive and non-invasive. Invasive types of breast cancer usually spread from the site of their origin. In this article, we’ll explain the different types of non-invasive breast cancer.

One of the types of breast cancer is non-invasive breast cancer. Also known as in situ cancer, here, the cancer cells are localized and have not spread from the breast tissue. Non-invasive breast cancer has two main types—ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS), as follows:

1. Ductal carcinoma in situ
Almost 20% of all breast cancers are most likely to be ductal carcinoma in situ (DCIS). It is a non-invasive form of breast cancer that is normally located within the milk ducts in the breast. In this type, cancer cells start growing in the milk duct and are at an early stage. Since this is an early stage, it is easy to cure this form of breast cancer. Sometimes, this type is also referred to as pre-cancer or Stage 0 breast cancer. It is because the cancer is localized to one small area. There is a possibility that this cancer can spread from the duct to other areas of the breast. It can even become invasive ductal carcinoma; however, this is rare. Immediate treatment will be needed when this type of cancer gets detected. There is a 1 in 3 chance of cancer recurring, even after treatment. It is very important to continue regular checkups to detect cases of recurrent cancer.

In some women, a lump may be felt in the breast or discharge may be observed from the nipple. It is not always easy to detect DCIS. A mammogram can be helpful to diagnose breast cancer at an early stage in order for the treatment to be effective. DCIS can be treated by breast-conserving surgery wherein the lump can be removed surgically. It may be combined with radiation therapy. If the DCIS has spread, then the removal of the entire breast may be required.

2. Lobular carcinoma in situ
Lobular carcinoma in situ (LCIS) is where cancer cells are located in the lobules of the breast and have not spread. Some experts do not consider this as carcinoma and instead refer to it as lobular neoplasia, which is a collection of abnormal cells in the lobules. Commonly, LCIS is diagnosed in menopausal women. It is not a common condition, and there are no apparent symptoms. Also, it may not be possible to detect LCIS even through a mammogram. LCIS can be mostly found during a biopsy performed on the breast.

Having LCIS increases the risk of developing invasive lobular carcinoma. Those having LCIS need to undergo regular screening to ensure timely treatment if cancer returns. LCIS does not require any treatment. It requires frequent monitoring and observation to detect the development of an invasive form of cancer in the lobules.

These types of non-invasive breast cancer are mostly pre-cancerous and may not always require treatment. However, monitoring is needed to ensure they do not develop into invasive cancers.