Hodgkin’s Lymphoma: An Environmental Scan
Table of Contents
Given there is no single diagnostic test to confirm a case of HL, the diagnosis requires a complete physical exam, the consideration of B-symptoms if present and the results of a number of clinical and laboratory tests. The clinical diagnostic work-up includes: a complete physical exam, thorough medical history, a lymph node biopsy, blood tests, imaging testing (Computed Tomography and Positron Emission Tomography scans), both cardiac and pulmonary functioning tests and possibly the examination of a bone marrow sample. The physical exam allows the physician to identify any lymph nodes that may be swollen along with examining other areas of the body to detect a build-up of fluid, which are most often found in the chest and abdomen areas.
Biopsies are performed by using either a local or general anesthetic and involve extracting a small portion of tissue through a needle or the excision of an entire lymph node. Many clinicians have a preference for a full excision of tissue rather than a needle biopsy as the excision procedure is more apt to harvest enough tissue for a thorough pathological analysis (Punnett, Tsang, and Hodgson 2010). The biopsied tissue is examined by a pathologist, who will examine the tissue for abnormal cells. In the case of HL, the pathologist will identify RS cells along with other abnormal cells present within the tissue sample. The results of a biopsy are crucial not only for an accurate diagnosis but also if a positive identification of HL is found. The pathology results are extremely important in determining the best course of treatment. In some cases, it is preferential that a hematopathologist, which is a pathologist who specializes in lymphoma, also examines the biopsied tissue.
Specific blood tests are performed in order to examine different components of blood, such as red and white blood cells along with platelets to see whether or not the cells are normal and to count the occurrence of the different types of cells contained within the sample. Additionally, results of blood work can also detect whether or not a tumor is impeding liver or kidney function. Finally, a process called immunophenotyping is important to classify the specific sub-type of lymphoma. Each cancer cell has specific molecular markers or antigens on the surface of each cell, examining the antigens aids in specifying the correct tumor type (Küppers, Yahalom, and Josting 2006).
Another important aspect of diagnosing lymphomas is various imaging tests including x-rays and Computed Tomography (CT), Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET) scans. For example, CT scans provide a detailed image and can help deduce how many lymph nodes are involved along with whether or not major organs are affected. The purpose of all imaging techniques in diagnosing HL is to determine the extent or invasiveness of any tumors and to gauge the overall spread of the disease throughout the body. X-rays are used to ascertain whether or not the disease is ‘bulky’. Clinically, the term tumor bulk designates any type of swelling or lump in the body that may or may not be malignant. In terms of HL, an x-ray will allow physicians to determine if the disease is either low or high bulk. A low-bulk tumor is a single mass of tumor tissue that is less than 10 centimeters in diameter whereas one that is larger than 10 cm is referred to as high-bulk or bulky disease (Punnett, Tsang, and Hodgson 2010).
MRI images return similar information to CT scans; however, an MRI is particularly useful to examine the nervous system including the brain and spinal cord, which is important as tumors may interfere with nervous system functions. As with other scans, PET scans are useful in providing detailed information about the stage of the disease and intrical in providing information for specific treatment options and approaches customized to an individual, while also important for gathering information during or after different treatment modalities to gauge how the cancer is responding to treatment. Previously, another scan known as a Gallium scan was used frequently in the diagnosis and treatment of HL. Both the PET and Gallium scans use a radioactive element that collects within a tumor to assist in determining where the tumors are within the body along with whether or not such tumors are responding to treatment. Recently, PET scans have primarily replaced the use of Gallium scans as the PET scan is much more sensitive (Lymphoma Research Foundation 2009).
In addition to x-rays and scans, many individuals undergoing diagnostic tests for HL have both cardiac and pulmonary (heart and lung) assessments. A multi gated acquisition scan (MUGA) allows clinical staff to assess how well a patient’s heart ventricles are working. This is very important for individuals who will undergo a particular form of chemotherapy known as ABVD. Each letter in the acronym denotes the first letter for the drug used in that form of combination chemotherapy drugs. For example, the ‘A’ in ABVD stands for Adriamycin. This drug is known for toxicity that specifically affects the heart. A MUGA scan provides clinicians a base line for cardiac function, along with assessing whether or not chemotherapy is hindering such function (for more information regarding chemotherapy approaches see the Conventional Treatment, section 3.10). Similar to the MUGA scan is the pulmonary function test, which assesses lung function. Again, the B component of ABVD combination chemotherapy, the bleomycin is known to have a toxic effect on the lungs and this test provides both a baseline and on-going information regarding pulmonary function.
The diagnosis of HL is a complex process of taking all the information from the physical exam, medical history and clinical and laboratory tests to a) determine whether or not an individual has HL and if present, b) use the diagnostic test results to inform the best options for treatment. In most cases, many of the diagnostic tests discussed above are repeated throughout the course of treatment (Lymphoma Research Foundation 2009).