The treatment for cutaneous B-cell lymphoma (CBCL) is based on the histology (what the cells look like under the microscope), where the lesions are located on the body, and the size and number of lesions.55 Depending on these factors, the types of therapies can vary from a “watch and wait” approach to surgical removal of the lesion, intralesional therapy (injections into the lesion), radiation, biologic agents, or chemotherapy. Treatment options for CBCLs depend on which specific slow-growing or fast-growing disease is diagnosed and the TNM classification or staging of the disease.
The TNM system considers the amount of skin involvement of the tumor (T), involvement of the lymph nodes (N), and whether the tumor has metastasized (M) to involve other lymph nodes.1,56 Comprehensive lymphoma staging with laboratory imaging and bone marrow biopsy are important for determining the prognosis.
For patients with CBCL who are not experiencing symptoms and who have a low tumor burden, it is often recommended that treatment be reserved for when symptoms appear. This approach is called “watchful waiting” or “watch and wait.” Although patients do not initially receive anti-lymphoma treatment, the lymphoma is not being ignored. By contrast, the patients’ overall health and disease are monitored through regular checkup visits through an active observation strategy to closely follow the disease. Laboratory and imaging tests are performed just as often as follow-up evaluations for active treatment would be. When and if the patient begins to develop symptoms or there are signs that the disease is progressing, active treatment is started.
The advantages of watch and wait over active treatment for disease that is not progressing are that patients do not experience the many possible side effects associated with anti-cancer treatments, which can negatively impact patients’ quality of life. Treatments are also associated with expenses and lifestyle burdens for the patient.
Radiation therapy has a high rate of effectiveness, with most patients having a complete response (100% clearance of skin lesions).57,58 However, about one-half of patients will experience a recurrence of the tumor, usually in another location.58 Patients who have more than one lesion have a higher risk of recurrence than those with a single lesion.
External beam radiation therapy is a type of radiation where a special beam of radiation is aimed directly at the lesion. This type of therapy is a local therapy that only treats a specific area of the body. Patients are given a radiation dose through a special machine that rotates around the patient. This rotation allows the lesion to be accessed from different angles, which provides a more complete treatment. In one study of 18 patients, almost three-quarters of patients responded to a low-dose treatment.59 However, some patients had to be retreated after a few months because the lesion remained or recurred.
When many small lesions are present, a small amount of drug—usually interferon,37 corticosteroid, or the monoclonal antibody rituximab (Rituxan®; described under Biologic Therapies)60—can be injected directly into the lesion.55
This type of treatment has only been tested in a limited number of patients, so there is much that is still not well understood. However, in the limited studies that have been done, patients did not experience adverse reactions except pain at the injection site. The rates of complete remission with this treatment are high and, in some cases, lesions other than the one injected showed regression. However, recurrences were also common.
Rituximab was the first monoclonal antibody approved by the US Food and Drug Administration (FDA) for cancer. Rituximab targets the CD20 antigen, which is on the surface of both normal and abnormal cells. The CD20 molecule is a key target for anti-cancer therapies because it is highly expressed in most B-cell malignancies.
Rituximab is the most common biologic drug used in lymphoma treatment regimens, either alone or in combination with standard chemotherapy regimens. For example, rituximab is used as first-line therapy with CHOP for aggressive B-cell lymphomas.
With systemic rituximab therapy, there is a drop in the number of normal B cells as well as a decrease in the malignant lymphoma cells. This is a reasonable treatment for patients with multiple and/or symptomatic lesions, widespread disease, and involvement of sites that are not appropriate for radiotherapy, such as the head. Most patients respond to treatment for 4 to 39 months before relapse.55,62-64
Radioimmunotherapy (RIT) is a targeted delivery system to help kill cancerous cells. With this treatment, a monoclonal antibody is attached to a radioactive element. The monoclonal antibody recognizes the cancer cells and takes the radioactive element to the cancer cell to kill it.
RIT consists of a targeted therapy such as rituximab with a source of radiation attached. RIT acts as a “guided missile” to destroy cancer cells by attaching to the lymphoma cell and delivering small doses of medicine and radioactivity to it.
There are 2 RIT products currently approved by the FDA: yttrium-90 (90Y)-ibritumomab tiuxetan (Zevalin®)65 and tositumomab (Bexxar). Both treatments recognize the specific antigen CD20 on the surface of cancer cells in patients with B-cell non-Hodgkin lymphoma.
In general, 90Y-ibritumomab tiuxetan and tositumomab cause fewer side effects than traditional chemotherapy agents.
GlaxoSmithKline recently announced plans to discontinue the manufacture and sale of tositumomab in 2014, so the availability of this RIT will be limited.
For both 90Y-ibritumomab tiuxetan and tositumomab, serious complications may include skin infections, severe allergic reactions, and temporary lowering of blood cell counts. These drugs are usually given when patients do not respond to rituximab.