Non Hodgkin's Lymphoma
Cyberfamily
Diffuse Large B-cell Lymphoma
Diffuse
Large B-cell Lymphoma
This is the most common of all the lymphomas, and by far the most
common of the aggressive types of lymphoma. It comprises about 35%
of all NHL cases in North America, and about 60% of all aggressive cases. The
term diffuse refers to the fact that the cancer cells are spread
around and not concentrated in one particular
part of the node or in clusters within a part of the node. In other
words the cancer cells don't clump together very well. This is
the opposite behaviour of follicular
lymphoma, which is an indolent variety.
This diffuse pattern of growth contributes to the aggressive behaviour of DLBC. These patients are more likely to experience "B" symptoms which includes fever, recurrent night sweats, fatigue or weight loss. However their aggressive natures is also what contributes to their high cure rate because chemotherapy is most effective at targeting rapidly dividing cells. The International Prognostic Index, is highly predictive of those who are at risk of early relapse.
DLBC is usually treated with R-CHOP (CHOP with Rituxan) chemotherapy or other Doxorubicin containing regimens. Many patients will be cured using this chemotherapy regimen. A "cure" is generally defined as 5 year disease free survival. The aggressive nature of DLBC means that if it has not relapsed within 5 years it is statistically highly unlikely that it ever will. In fact the vast majority of relapses occur within the first 2 years following treatment. While a relapse after 5 years is unlikely it does occur in a small subset of patients.
There is ongoing study about the best schedule for R-CHOP. Traditionally CHOP was given every 3 weeks (CHOP-21). But studies using a dose dense schedule CHOP-14 (every 2 weeks) showed superior outcomes for patients over the age of 60. However with the addition of Rituxan to this combination. Below is the link to the latest update for that particular study (Feb 2008)
An earlier study showed that adding Rituxan to CHOP-14 (making it R-CHOP-14) for only 6 cycles was superior to using standard CHOP-21 for eight cycles. Therefore there is little reason to continue CHOP for 8 cycles and expose the patient to excessive anthracyclines. Below is the link to that study.
Now the question that needs to be answer is whether or not R-CHOP-14 is superior to R-CHOP-21. As yet that is an unanswered question that needs to be studied in a Phase III trial.
Here is the link to an analysis of these studies from
Dr. Andrew Zelenetz
If a relapse occurs a more potent salvage therapy will be used. In most cases if the patient is under 70 and in good general health a Stem Cell Transplant will be the treatment of choice for a relapse. Stem Cell transplants are highly effective and can cure about 30% of patients who undergo them. There are two basic types of Stem Cell Transplant.
Allogeneic - where someone else is the donor. This type has a very high probability of curing the patient, but is also very risky. About 20-30% of patients die during this procedure.
Autologous - where the patient donates their own stem cells. This type is very safe (2% death rate) but does not produce the high rate of cures that allogeneic transplants to.
Not everyone is a candidate for a stem cell transplant. Other treatment options are available with varying degrees of success. For a list of alternative treatments to SCT click on the relapsed DLBC menu choice at the top left of this page.
Additional information
Recent research has identified two distinct types of DLBC. Using modern techniques such as DNA Microarray analysis, and Flow Cytometry, researchers have discovered that DLBC can be divided into Germinal B-Cell (GBC) and Activated B-Cell (ABC) types of diffuse large B-cell lymphoma. The GBC variant has a very favourable prognosis with a 5 year survival rate around 70-80% in most studies. The ABC variant is a poor prognosis with only about 30-40% 5 year survival. It still remains a challenge for researchers and doctors to find ways to use this information to develop treatments that make use of the knowledge and help boost the ABC survival rate. It is hoped that in the future they will be able to tailor the treatment to the subtype.
Here is a list of medical studies on this subject.
-
Evaluation of immunophenotype in diffuse large B-cell lymphoma and its impact on prognosis.
-
Distinct types of diffuse large B-cell lymphoma identified by gene expression profiling.
- Gene expression profiling of diffuse large B-cell lymphoma.
Click here to run a focused Medline search
for more abstracts on this topic
Furthermore, additional studies are beginning to show that the GBC and ABC variant is not the deciding factor in the prognosis. They are finding other genetic features that are perhaps of more prognostic value.
Here are some studies looking at this topic.
Another variant
of DLBC is T-cell/Histiocyte - Rich B-cell Lymphoma. Despite the
name this not a T-cell lymphoma, but a form of DLBC. The link below
takes you to an excellent article on this type of NHL
Biology, Diagnosis and Management of T-cell Histiocyte-Rich DLBC
To read more about diffuse large b-cell lymphoma check out the following links.
National Cancer Institute aggressive NHL information
(Note, follow the links on the left side of this page for additional information since it is all categorized.)
Because this type of lymphoma is the most common type there is an abundance of information about it on the Internet. But for the average person who is looking for treatment options the best place to look is likely going to the be American Society of Hematology) ASH abstracts. These abstracts represent the ground breaking work of the worlds leading haematologists as presented at their annual convention.
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