Non-Hodgkin's lymphoma (NHL) is a cancer that starts in cells called lymphocytes, according to the American Cancer Society. The lymphocytes are cells of the immune system and can be found in lymph nodes, the spleen and bone marrow. The National Cancer Institute estimates that in 2009, approximately 65,980 new cases of NHL were diagnosed in the United States. Once NHL is diagnosed, it is then staged. Staging is a standardized way of describing the extent and spread of the cancer and helps to guide treatment and prognosis.
Stage I
The American Cancer Society describes the first stage of NHL as consisting of cancer that is found either only in one lymph node or nodes in only one area, like the groin or underarm; or the cancer is in only one area of a solitary organ besides the lymph system.
Stage II
Stage II NHL is split into two subsections. Stage II consists of lymphoma that is either in two or more groups of lymph nodes on the same side of the diaphragm (above or below), and Stage IIE (E for extranodal), in which the lymphoma has spread from one group of lymph nodes into an adjacent organ, according to the National Cancer Institute.
Stage III
The third stage of NHL can be broken down into Stage III, Stage IIIE, Stage IIIS and Stage IIIE+S. Stage III NHL describes lymphoma that is found in groups of lymph nodes above and below the diaphragm; in Stage IIIE, the cancer is also in an organ adjacent to the lymph nodes; Stage IIIS is diagnosed when lymphoma is also in the spleen; and Stage IIIE+S describes when cancer is in the lymph nodes, an adjacent organ and the spleen.
Stage IV
In the last stage of NHL, Stage IV, the lymphoma has spread past the lymph system to an organ that is not adjacent to any nodes; or the cancer has spread to the bone marrow, liver, brain, spinal cord, or the lining around the lungs (which is called the pleura).
