Online Books > Ductal Carcinoma in situ Of The Breast (DCIS): A Guide For Patients

What Is Cancer?

One of the most confusing aspects about being told that you have ductal carcinoma in situ (DCIS) of the breast is that the terms cancer, carcinoma, malignancy, tumor, growth, lump, nodule, pre-malignancy, neoplasm, and others, are around by doctors and other health care providers. As a patient, it is really difficult to sort out exactly what all these terms mean.

Cancer is a form of abnormal cell growth in tissues of the body. Under normal circumstances, as we grow and age, the individual cells in the tissues of the body will replace themselves through a regular process of cell growth. This process is usually very regular and organized. When growth of the cells of an organ becomes out of control, the resulting tissue may form a lump of abnormal cells, or a nodule, or a growth of tissue made up of cells that no longer are doing the job they were meant to do.

Here are some working definitions to help sort out the confusing terms that are used to describe breast lumps that might occur due to abnormal cell growth:

A "Growth:" this is a non-specific term that described a collection of tissue that is growing in a way that is different than the healthy normal tissue would grow. Growths can be benign tissue, such as a scar or a wart, or can be cancers. Another term for a growth can be a lump or a nodule. These terms are not very helpful in that they don¹t tell us how the abnormal tissues are likely to behave.

Tumor: This is a growth of tissue that is growing out of control. Another term for this is Neoplasm.

Benign Tumor: These are collections of slightly abnormal cells that usually grow slowly, and stay in the site where they originally started. They do not spread, and do not invade into other parts of the body. These are non-cancerous or non-malignant.

Malignant Tumor: These are collections of very abnormal cells that tend to grow rapidly and without control. These tumors can invade other tissues and organs, and spread to other parts of the body through the bloodstream and through the lymph system.

A malignant tumor will first grow only in the organ where it started. This initial tumor is known as the primary tumor. The primary tumor may invade or infiltrate directly into other adjacent organs. Very often the first organ system that a cancer invades is the vascular system-- the small blood vessels and lymphatic vessels that bring fluid nourishment to the tumor. Once the tumor cells invade into the blood or lymphatic stream , they can be whisked away to other parts of the body, where they will then take root and start to grow new small tumors (known as metastases). Malignant tumors are very often life-threatening illnesses.

Another term for a malignant tumor is invasive tumor or cancer: A specific type of malignancy arising from the glandular tissues of the body is called a carcinoma. When a cancer or carcinoma does spread it is said to have metastasized.

Carcinoma in situ: is a cancer that involves only the tissue in which it began. In situ is a Latin term which means " in its own situation". Carcinoma in situ has not yet started to invade into the surrounding tissues or lymphatics or blood vessels, so it cannot yet spread; it cannot metastasize. It is a tumor that is in a pre-malignant phase. If not adequately treated, some carcinomas in situ will go on and become invasive and become fully malignant.

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