Follicular lymphoma: Description, Causes and Risk Factors:
Follicular lymphoma is the most common form of low-grade non-Hodgkin's lymphoma (NHL) in the Western hemisphere. This disease impacts centrocytes and centroblasts which are types of B cells. It is called follicular lymphoma because of its distinct pattern of appearance and the follicular composition of the tumor.
The tumor is composed of follicles containing a mixture of centrocytes or cleaved follicle center cells, "small cells", and centroblasts or large noncleaved follicle center cells, "large cells". These follicles are surrounded by non-malignant cells, mostly T-cells. In the follicles, centrocytes typically predominate; centroblasts are usually in minority.
The disease course is typically indolent, but 25-60% of cases may transform to an aggressive diffuse large B cell lymphoma (DLBCL). FL is characterized by t(14;18)(q32;q21), resulting in dysregulated expression of the anti-apoptotic BCL-2 and accumulation of follicle center cells with prolonged survival. Secondary genetic alterations involving p53, p16INK4a, c-Myc, and BCL-6 have been associated with transformation to DLBCL.
High grade follicular lymphomas may often lack this translocation. A number of other genetic abnormalities are also seen.
Stage I: Involvement of a single lymph-node region (I) or a single extralymphatic organ or site (IE).
- Stage II: Involvement of two or more lymph-node regions on the same side of the diaphragm (II) or localized involvement of an extra-lymphatic organ or site (IIE).
- Stage III: Involvement of lymph-node regions on both sides of the diaphragm (III) or localized involvement of an extra-lymphatic organ or site (IIIE), spleen (IIIS), or both (IIISE)
- Stage IV: Diffuse or disseminated involvement of one or more extralymphatic organs, with or without associated lymph-node involvement; the organ(s) involved should be identified by a symbol: (P) pulmonary, (O) osseous, or (H) hepatic.
According to the WHO criteria, the disease is morphologically graded into:
Grade 1 (<5 centroblasts per high-power field (hpf)).
- Grade 2 (6-15 centroblasts/hpf).
- Grade 3 (>15 centroblasts/hpf).
Grade 3 is further subdivided into:
Grade 3a (centrocytes still present).
- Grade 3b (the follicles consist almost entirely of centroblasts).
The initial symptoms of follicular lymphoma include swelling of one of more lymph nodes
. They become tender to touch. By the time the tumor spread to other parts of the body, it turns harder for the healthy cells to strive while the body organs become malnourished. If you notice drastic weight loss without any changes in your diet, it is also the sign of follicular lymphoma. Another symptoms is internal discomfort, as the organs swell and body mass decreased
, pressure can build up and be quite painful. Keep in mid that a follicular lymphoma is slow growing type of cancer, patients may not feel any symptoms until it shows in the advances stages of the disease.
Doctors usually diagnose follicular lymphoma by takinga small sample of the tumor, called a biopsy, and lookingat the cells under a microscope. In addition, follicularlymphoma cells often carry abundant amounts of a proteincalled BCL-2, which protects cells from dying. Additionaltests, such as blood tests, x-rays and scans may be used tohelp determine how far the cancer has spread, indicatingits “stage.”
Follicular lymphoma can exhibit variant histologic patterns that can lead to confusion with other B-cell lymphomas and reactive conditions.Diagnostic markers such as CD10 and BCL2 may be difficult to interpret in variant FL patterns, and are often diminished or absent in the interfollicular and diffuse components.
In general, the average survival rate for follicular lymphoma is 7 - 10 years, depending on other risk factors. New drug treatments, particularly monoclonal antibodies, have significantly improved survival rates. According to a recent study, 91% of patients with follicular lymphoma now survive the first 4 years after diagnosis, compared with 69% of patients treated in the past with older types of drugs.
Treatment options depend on the stage and grade of the disease.
Radiation treatment is often used to treat early-stage (I and II) follicular lymphoma. High-energy x-rays targeted at specific groups of involved lymph nodes can provide cure in some patients with limited disease. In addition to radiation, doctors may use chemotherapy to control this disease. Unlike many cancers, the follicular lymphomas tend to be very sensitive to both radiation and chemotherapy. There are many drugs or combinations of drugs that can be used to manage this disease. They may include cyclophosphamide, vincristine, prednisone (CVP), cyclophosphamide, doxorubicin, vincristine, prednisone (CHOP), Fludarabine (+/- mitoxantrone, +/- cyclophosphamide), 2-chlorodeoxyadenosine (2-CdA), chlorambucil (+/- prednisone), Rituxan, Bexxar, Zevalin.
For patients with relapsed follicular lymphoma, high dose chemotherapy and an autologous stem cell transplant or an allogeneic (or “mini”-allogeneic) transplant may be an option that provides a prolonged disease-free interval in some patients.
Although initial responses to treatment with chemotherapy are often quite good, over time lymphoma cells will learn how to become resistant to treatment, meaning the drugs no longer work. This is called drug resistant lymphoma. In these cases, drugs like Bexxar or Zevalin, which can target the tumor with a monoclonal antibody armed with a dose of radiation, have been found to be particularly useful. These drugs are approved for the treatment of follicular lymphoma that has relapsed after chemotherapy. Some physicians are also currently testing this approach in newly diagnosed follicular lymphoma patients in combination with chemotherapy.
Some chemotherapy drugs can damage healthy cells and cause side effects such as nausea and vomiting, reduced appetite, hair loss and mouth sores. Damage to healthy immune cells may also put lymphoma patients undergoing treatment at risk for infection. Doctors can prescribe medicines to offset these effects. These include growth factors (G-CSF or GM-CSF, to protect against infection), erythropoietin (to prevent anemia) and anti-emetic drugs (for nausea).
New treatments for follicular lymphoma are being researched all the time. Your doctor may invite you to take part in a clinical trial to compare a new treatment against the best available standard treatment.
Your doctor must discuss the treatment with you and have your informed consent before entering you into a trial.
NOTE: The above information is educational purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.