Carcinoma in situ

Carcinoma in situ (CIS) is a type of cancer in which the cancer cells are still in the same place they started in the body. The cells haven't spread anywhere else yet. CIS is the earliest stage of cancer and it is not very dangerous. It is important to catch this kind of cancer early, so doctors can remove the cancer cells and make sure they don't spread to other parts of the body. Treating CIS can help people get better and stay healthy.