SD Full Form in Medical term is Stable Disease. Health experts use this term to denote a tumor that is neither shrinking nor growing. SD also means no new tumors have developed, and cancer has not spread throughout the body. It comes in a spectrum of treatment responses. And although it may be frustrating to hear, a tumor is not a static disease. Modern treatments such as immunotherapy and targeted therapies are also changing how doctors consider the idea of stable disease.
This does not mean that the stable disease is unchanged. This means that the change is not sufficient to suggest that there is either a partial response to treatment or disease progression.
A stable disease can also be an effective indication for new immunotherapy drugs. Doctors aim to achieve an immediate response when dealing with cancer. For example, Chemotherapy drugs are used in treatment because they detect cancer cells almost immediately.
It is said that the immunological reaction can influence the cells surrounding the tumor, creating benign lesions that copy cancer cells on a PET or CT scan.