How Do Doctors Determine Lymphoma Staging?
Staging is the classification of a cancer type by its size and whether and how much it has spread around the body. Determining a cancer's stage is very important because it tells the oncologist which treatment is most likely to work and what are the chances of remission or a cure (prognosis).
Staging of lymphomas depends on the results of imaging studies and related tests that reveal the extent of the cancer involvement.
HL is often described as being "bulky" or "nonbulky." Nonbulky means the tumor is small; bulky means the tumor is large. Nonbulky disease has a better prognosis than bulky disease.
NHL is a complicated set of diseases with a complex classification system. In fact, the classification system is continuously evolving as we learn more about these cancers. The newest classification system takes into account not only the microscopic appearance of the lymphoma but also its location in the body and genetic and molecular features.
Grade is also an important component of the NHL classification.
- Low grade: These are often called "indolent" or low-grade lymphomas because they are slow growing. Low-grade lymphomas are often widespread when discovered, but because they grow slowly, they usually do not require immediate treatment unless they compromise organ function. They are rarely cured and can transform over time to a combination of indolent and aggressive types.
- Intermediate grade: These are rapidly growing (aggressive) lymphomas that usually require immediate treatment, but they are often curable.
- High grade: These are very rapidly growing and aggressive lymphomas that require immediate, intensive treatment and are much less often curable.
The "staging," or evaluation of extent of disease, for both HL and NHL, are similar.
- Stage I (early disease): Lymphoma is located in a single lymph node region or in one lymphatic area.
- Stage IE: Cancer occurs in one area or organ outside the lymph node.
- Stage II (early disease): Lymphoma is located in two or more lymph node regions all located on the same side of the diaphragm.
- Stage IIE: As II, but cancer grows outside the lymph nodes in one organ or area on the same side of the diaphragm as the involved lymph nodes. (The diaphragm is a flat muscle that separates the chest from the abdomen.)
- Stage III (advanced disease): Lymphoma affects two or more lymph node regions, or one lymph node region and one organ, on opposite sides of the diaphragm.
- Stage IV (widespread or disseminated disease): Lymphoma is outside the lymph nodes and spleen and has spread to another area or organ such as the bone marrow, bone, or central nervous system.
If the cancer is also found in the spleen, an "S" is added to the classification.
Health researchers have extensively evaluated several risk factors shown to play a role in treatment outcome. For HL, the International Prognostic Index includes the following seven risk factors:
- Male sex
- Age 45 years or older
- Stage IV disease
- Albumin (blood test) less than 4.0 g/dL
- Hemoglobin (red blood cell level) less than 10.5 g/dL
- Elevated white blood cell (WBC) count of 15,000/mL
- Low lymphocyte counts less than 600/mL or less than 8% of total WBC
The absence of any of the above risk factors is associated with an 84% rate of control of Hodgkin's disease, whereas the presence of a risk factor is associated with a 77% rate of disease control. The presence of five or more risk factors was associated with a disease control rate of only 42%.
The treatment these patients received, which occurred primarily in the 1980s, determined their outcomes. Newer treatments for Hodgkin's lymphoma may improve these predicted outcomes. Furthermore, new treatments are being developed for patients with greater risk factors.
The International Prognostic Index for NHL includes five risk factors:
- Age older than 60 years
- Stage III or IV disease
- High LDH
- More than one extranodal site
- Poor performance status (as a measure of general health): From these factors, the following risk groups were identified:
- Low risk: no or one risk factor, has a five-year overall survival of approximately 73%
- Low-intermediate risk: two risk factors, has a five-year overall survival of approximately 50%
- High-intermediate risk: three risk factors, has a five-year overall survival of approximately 43%
- High risk: four or more risk factors, has a five-year overall survival of approximately 26%
The prognostic models were developed to evaluate groups of patients and are useful in developing therapeutic strategies. It is important to remember that any individual patient might have significantly different results than the above data, which represent statistical results for a patient group. There are specific IPIs for certain types of lymphoma, such as follicular or diffuse large B-cell.