The test offers clinicians a genetically-based survival index for people with diffuse large-B-cell lymphomas, the most common type of adult lymphoma. Current tests for these patients take several factors into account including the patient's age and the stage and spread of the disease. This new test is a better predictor than current prediction techniques, and both methods may eventually be used together for the best possible patient survival prediction.
Lymphomas are a group of cancers of the immune system's white blood cells (T-cells and B-cells), which often reside in the lymphatic system. This system is comprised of lymph nodes and other lymph tissue, which are found throughout the body, so lymphoma can arise in or spread to a range of tissue. There are two major forms of the lymphoma--Hodgkin's and non-Hodgkin's lymphoma (NHL), and there are many different types of NHL. Making an accurate diagnosis of a particular type of NHL is both critical, and a real challenge. Below, Dr. John Hainsworth of the Sarah Cannon Cancer Center, offers a basic introduction to the family of diseases known as non-Hodgkin's Lymphoma.
What is non-Hodgkin's lymphoma and how does it differ from Hodgkin's lymphoma?
JOHN D. HAINSWORTH, MD: Non-Hodgkin's lymphoma -- or NHL -- is actually a family of diseases that include all types of lymphomas. Hodgkin's lymphoma -- or Hodgkin's disease -- was one of the first lymphomas found, or described. After the discovery of Hodgkin's, it was found that there are actually different types of lymphomas that originate from different lymphocytes. So all forms found after Hodgkin's were lumped into this category of non-Hodgkin's lymphoma.
What are the most common types of NHL?
There are two types that are probably the most common -- and these two types act very differently. One is a group of lymphomas called the "follicular" lymphomas. They are generally low-grade, or non-agressive lymphomas. The second group is called "large-cell" lymphomas, and they are very aggressive. Without treatment, patients with large-cell lymphomas do very poorly, and in most cases the disease is fatal within a number of months.
What is the difference between lymphomas and leukemias?
In general, leukemias involve mostly the blood and the bone marrow. Lymphomas are much more likely to involve lymph nodes, other organs, and sometimes also the bone marrow.
Are there specific risk factors?
The risk factors for lymphomas are a number of other diseases that affect the immune system. Patients who have immune suppression -- because they have had transplants, autoimmune diseases (like rheumatoid arthritis, lupus), or HIV infection -- are at an increased risk of getting lymphoma.
What are the signs and symptoms of NHL? Do they differ from the symptoms of other blood cancers?
For the low-grade lymphomas, symptoms usually just involve finding some enlarged lymph nodes. Patients who have aggressive lymphomas usually feel very bad. They often have fatigue, weight loss, fevers, night sweats, and a variety of other problems. Local symptoms depend on which parts of the body the lymphoma involves.
How is NHL diagnosed?
The diagnosis is based on a biopsy of some kind, and diagnosing lymphoma is actually one of the most challenging diagnoses for pathologists. It's fairly easy to say, "This is a lymphoma." But sometimes it's not so easy to identify the type of lymphoma, which is very important for treatment.
Can NHL be cured?
Some lymphomas can be cured. In fact, for some of the types of aggressive lymphomas and large-cell lymphomas, the cure rate's pretty high. For other types of lymphoma, the answer is no. Follicular lymphomas traditionally cannot be cured, although often patients do well with them for a long time.
What are the treatment options for high-grade forms of lymphoma?
It is sort of paradoxical that the high-grade, more aggressive forms of lymphoma are actually the more treatable ones. These are the ones that, without treatment, patients die from in a few months. But, with appropriate treatment, these are the forms that are curable.
They traditionally have been treated with a fairly intensive combination of chemotherapy drugs. The drugs are given at the same time, usually for a period of four to six months.
And for patients with low-grade lymphoma?
There are one or two drugs designed to be easy to tolerate for these patients. Sometimes the treatments aren't given right away, and though these patients can live for a long time, they live with the lymphoma rather than actually getting rid of it.
And what does the future look like for lymphoma treatment?
There is a focus on new targeted treatments that look for specific differences between the diseased cells versus the normal cells, and therefore can treat the lymphoma without causing a lot of the side effects that we normally associate with cancer treatment.
So chemotherapies attack all the cells in the body, and these targeted therapies only attack specific cells, and therefore the reaction's not so violent?
That's generally correct, although chemotherapy drugs work against cancer cells better than they work against your normal cells. They work against cells that are rapidly dividing, and most cancer cells are dividing much more frequently than, say, cells in your lungs or in your heart or in normal organs.
What is an example of a targeted drug for lymphoma treatment?
Rituxan (rituximab) is the first targeted drug on the market that is used widely in B-cell lymphomas, and it's been an extraordinarily good drug.
It's already been shown that if you add Rituxan to the standard combination chemotherapy, you can cure more patients. That's the first time that's happened in a long time. In the low-grade lymphomas, these targeted drugs can provide another treatment option with minimal toxicity to patients and often can be used for several years without giving patients chemotherapy at all.
How do the side effects of these new targeted therapies compare with traditional chemotherapy?
We've had considerable experience with Rituxan during the last several years. This drug has none of the chemotherapy toxicity. No hair loss. No nausea and vomiting. No lowering of the blood counts. Also, Rituxan is given once a week for a short period of time and that's it, where chemotherapy treatments take about six months.
