Staging of Hodgkin's Disease
Once the physician has diagnosed lymphoma, he or she will want to perform studies to establish the patient's stage—that is, to find out how far the patient's cancer has spread. Staging helps the physician to select appropriate treatment options and helps him/her to arrive at a prognosis, or estimate of disease outlook and survival. Clinical information is reviewed, including findings from the physical examination, blood tests, and imaging studies. The imaging studies most often employed are chest X-ray and computed tomographic (CT) scan of the chest, abdomen, and pelvis.
One of the hallmarks of HD is that it tends to spread from one lymph node set to the next, without "skipping" an area unless the disease has progressed very far. HD rarely invades single, nonlymphatic organs or sites, and it does not tend to spread to nearby organs. Because of these characteristics, HD is "staged" according to sites of involvement in relation to the diaphragm, the major muscle of the abdomen that is used for breathing.
If the patient has Hodgkin's Disease (HD), the physician may order additional tests such as a gallium scan and lymphangiography. In addition, a bone marrow biopsy may be obtained.
Tests to Stage Hodgkin's Disease
Gallium scanning—Gallium scanning is a nuclear medicine procedure. Radioactive gallium is injected into the patient's vein, and it is taken up by malignant lymphoma cells. A specialized camera then is used to produce a picture of the pooled gallium, which will identify the size and sites of cancerous areas. Gallium scanning is particularly useful when HD is located in the patient's chest; however, this procedure is used more often to help predict recurrence in patients with radiologic abnormalities that remain after therapy.
Lymphangiography—Lymphangiography is an X-ray technique that helps to reveal cancerous tissue in the lymphatic vessels after a special dye is injected into the lymphatic system. A lymphatic vessel in the foot often is chosen as an injection site if the physician suspects that HD has invaded the abdomen and pelvis.
Laparotomy—In most patients, clinical staging is all that is required to begin treatment planning. Yet, in some cases, the physician may request an exploratory laparotomy, surgery performed through an abdominal incision, for direct pathological staging. Laparotomy is a very invasive procedure—that is, it involves a large incision and many surgical instruments—but it is also the most accurate method for evaluating the spread of disease by direct observation and for biopsying small pieces of tissue. A pathologist will review such biopsies. The surgeon sometimes removes the spleen during laparotomy.
Laparotomy is performed much less often than it was a decade ago. Many specialists believe that laparotomy should be used as a staging procedure only if it alters therapy—in other words, if the physician is planning to administer chemotherapy or a combined treatment plan, there is no need to proceed with laparotomy.