How is lymphoma "staged"?

How is lymphoma "staged"?

In terms of staging and grading of lymphomas, I think the most important thing in terms of identifying, prognosis, and response to treatment of lymphoma, and duration of treatment is the stage of a lymphoma. Stage one lymphomas, whether it be non-Hodgkin's' lymphoma or Hodgkin's' lymphoma, involves only one lymph node group, whether it be the neck or the groin, one group only. Stage two lymphoma involves two non-contiguous (not connected) lymph node groups. So one lymphoma on the neck and another lymphoma in an armpit, or one side of the neck and one armpit, or one side of the neck and another side of the neck, or two non-contiguous lymph node groups. Stage three is when you have lymphomas on lymph nodes on both sides of the diaphragm, so crossing the mid-line. So, a lymphoma on a lymph node group on the neck and a lymphoma on a lymph node group in the groin constitutes stage three. And then stage four is any time you have bone marrow involvement in the lymphoma, or involvement of non-lymph node groups in the lymphoma. And the stagings get even more complicated if there's involvement of the spleen in the lymphoma or involvement of the small intestine or large intestine in the lymphoma, but for all intents and purposes of defining stage, one through four is the easiest way to identify lymphoma.