Ann Arbor Staging System

The Ann Arbor Staging System is used to classify the extent of lymphoma, a type of blood cancer. It helps doctors understand how far the cancer has spread in the body. The system uses Roman numerals I to IV: I indicates involvement of a single lymph node group or a single area; II involves multiple lymph node groups on the same side of the diaphragm; III indicates spread to lymph nodes on both sides of the diaphragm; and IV signifies widespread disease, often outside lymph nodes into organs or tissues. This staging guides treatment decisions and helps predict prognosis.