Biopsy
The first step in treating NHL is making an accurate diagnosis. When the symptoms and findings on physical examination raise the possibility of a non-Hodgkin lymphoma diagnosis, laboratory tests and radiology tests will usually be done to help guide how best to determine the diagnosis. To make a definite non-Hodgkin lymphoma diagnosis, a sample of the tumor needs to be obtained for evaluation by the pathologist. This is usually done by having a surgeon or interventional radiology doctor remove a piece of tumor (biopsy). Sometimes the diagnosis may be made by evaluating fluid removed from the chest or abdomen or by removing a small piece of bone marrow to be examined under the microscope.
Staging
The second step in treating NHL is to determine how much the disease has spread within the body. The extent of disease is called the "stage" of the lymphoma. Knowing the stage helps to determine the strength of the treatment that is needed to cure the lymphoma. The process of finding all of the sites of disease in the body is called "staging." Staging involves doing radiology tests, such as PET, CT, and MRI scans; sampling the bone marrow with a needle into the hip bones; and obtaining spinal fluid with a needle into the space between the bones of the lower spine (lumbar puncture).
The information learned from the scans and from the bone marrow and spinal fluid evaluations is used to assign a "stage" that describes how extensive the lymphoma is. More than one staging system is used for non-Hodgkin lymphoma. While in adult non-Hodgkin lymphoma a system called the Ann Arbor Staging System is commonly used, in childhood non-Hodgkin lymphoma the most common system of staging is the St. Jude/Murphy Staging System. This system is summarized below:
- Stage I: The tumor is at one site only, except not in the chest, abdomen, or next to the spine or brain.
- Stage II: The tumor is at two or more sites, all either in the upper half or the lower half of the body, but not in the chest, next to the spine or brain, or in the abdomen (unless completely surgically removed). The division between the upper and lower body is at the breathing muscle called the diaphragm that separates the chest from the abdomen.
- Stage III: The tumor is at two or more sites in both the upper and lower halves of the body or any tumor in the chest, any tumor in the abdomen that is not removed by surgery, and any tumor next to the spinal cord or brain but does not involve the bone marrow or the central nervous system (the brain or spinal fluid).
- Stage IV: The tumor is at any location and also is in the bone marrow and/or central nervous system. Stage IV is also subdivided depending on the amount of cancer cells present in the bone marrow. If more than 25% lymphoma cells are present in the bone marrow, the condition is generally considered to be leukemia rather than lymphoma.
Because the common childhood non-Hodgkin lymphomas often are located in the chest, abdomen, or next to the spine or brain, many children with non-Hodgkin lymphoma have stage III or IV disease when they are diagnosed.