Lymphoma invading into the bone marrow belongs to stage IV of lymphoma. Lymphoma is divided into stage IV. Stage I and II belong to early stage lymphoma. Early stage lymphoma refers to lymphoma invading one lymph node area or two lymph node areas, but all of them are distributed above the diaphragm or below the diaphragm. Stage IV lymphoma mainly refers to invasion of bone marrow, or invasion of lung, liver, soft tissue, etc. After the lymphoma invades the bone marrow, although it is advanced lymphoma or stage IV lymphoma, it can still be treated by chemotherapy and immune-targeted therapy, together with local radiotherapy. The prognosis is relatively poor, but the 5-year survival rate of patients is around 30%-40%.