Carcinoma in situ is the earliest stage of cancer, where the cancer cells remain at their original site and have not spread to nearby tissues or organs in the body. Cancer can remain in this dormant stage for many months or even years before it can multiply and spread to other parts of the body. In carcinoma in situ, the cancer cells don’t have the ability to create new blood vessels for sustenance and thus cannot grow or spread.In time however, a mutation or change in the cancer cell genes gives them the ability to stimulate new blood vessels, helping them to grow and spread. Carcinoma in situ commonly occurs in breast tissues, cervix and skin.
Since carcinoma in situ is made up of only a small number of cells, it may be difficult to detect with X-rays or scans. However, it can be diagnosed with some screening tests and biopsy. Carcinoma in situ can be treated by the removal of the cancer cells before it can progress.