Once the diagnosis of a lymphoma has been made, tests may be performed to determine how far the cancer has spread. This is called staging. These tests are important because they help physicians choose the most effective type of treatment. In particular, the length and intensity of treatment required for the cure of Hodgkin lymphoma is determined by the stage of the lymphoma.
Various diagnostic studies may be performed as part of the staging process. These include:
Chest X-ray
A chest x-ray is used to identify masses in the upper chest (mediastinum) or lungs.
Computed Tomography (CT) Scan
A CT scan is used to obtain a clear picture of the internal organs, and can be used to identify the size and location of a mass that could be a lymphoma.
Gallium Scan
The gallium scan provides the best measure possible of the activity of cancer tumors. In this study, a small quantity of radioactive gallium is introduced into the body. A scan is then taken of the patient to determine where the gallium is concentrated within the body. Most lymphomas will absorb more gallium than healthy tissues of the body (except for the cells of the liver and spleen) will. During and after treatment, the gallium scan is repeated to look for evidence of active tumors and to monitor the patient for a recurrence of cancer. Scans that have shown abnormal lymph nodes are repeated as well, both during and after therapy, to see how well treatment has performed.
Bone Marrow Biopsy
The bone marrow may be affected with malignant lymphoma and thus may require biopsy to detect disease. During a bone marrow biopsy, bone marrow is taken from the back of the pelvis. To minimize pain and discomfort, this procedure is performed while the patient is under anesthesia.
Magnetic Resonance Imaging (MRI)
In selected cases, MRI can provide information about the location of the disease within the body. This procedure is often helpful in distinguishing the extent and location of lymphoma in the bone or bone marrow.
Positron Emission Tomography (PET) Scan
Recent studies indicate that PET scans may be highly sensitive in determining whether active sites of tumor involvement are present in patients with lymphomas. In many centers, physicians have replaced the use of the gallium scan with the PET scan. During and after treatment, the PET scan is repeated to look for evidence of active tumors and to monitor the patient for a recurrence of cancer. Scans that have shown abnormal lymph nodes are repeated as well, both during and after therapy, to see how well treatment has performed.
In addition to the diagnostic tests performed for staging, further studies are done to determine the safety of administering particular therapies or treatments to individual patients. An echocardiogram is a test that uses high-frequency sound waves to examine the structure and function of the heart. A study called pulmonary function testing is also performed to assess the functional status of the lungs as a baseline before treatment. Depending on the diagnosis, staging, and evaluation studies may differ among patients.
Determination of Disease Stage
Once physicians gather all the information available from the diagnostic testing and evaluation of the extent of involvement of the lymphoma, they then stage the lymphoma (determine the extent it has spread throughout the body).
Stage I
Involvement of a single lymph node or lymph node group or site outside of the lymphatic system.
Stage II
Disease in more than one group of lymph nodes on one side of the diaphragm or one site outside of the lymphatic system plus one or more lymph node regions on the same side of the diaphragm.
Stage III
Involvement of lymph nodes on both sides of the diaphragm that may be accompanied by involvement of the spleen (Stage IIIS), or localized involvement of an organ or site outside of the lymphatic system (Stage IIIE), or both (Stage IIIE+S) sides of the diaphragm.
Stage IV
Widespread disease spread outside the lymphatic system, such as in the bone marrow, spleen, lung, or liver, with or without lymph node involvement.
Modifiers may be included in the diagnostic evaluation to add more information about a patient's condition. These modifiers include the absence (A for absence of symptoms)or presence of fever, weight loss, or night sweats (B for presence of symptoms); whether the disease has spread beyond the lymph nodes (extranodal); whether there is disease in the liver and/or the spleen; and whether the size of the lymph nodes is greater than six centimeters, whether the disease that has spread to more than four lymph node groups, or disease that has spread throughout more than one third of the chest cavity ( bulk disease).
