Non-Hodgkin's Lymphoma
Basic Information
Non-Hodgkin's Lymphoma (NHL) is a form of cancer in which a group of malignant cells spread throughout the lymphoid tissue. The lymphatic system consists of the lymph nodes and the lymph vessels that connect the nodes. Lymph nodes are small groupings of white blood cells (or lymphocytes), mostly found near the neck, the collar bone, and armpits. The primary purpose of the nodes is the production of lymphocytes, the component of the blood that fights infection. In particular, lymphocytes consist of three different kinds of blood cells that are all essential to the efficient functioning of the immune system. B cells create antibodies that destroy infectious contagions like bacteria, fungi, and viruses. T cells help and reinforce the B cells. Natural killer (NK) cells have the ability to attack and kill cancerous cells.
NHL is considered an acquired disease, rather than one that is genetically inherited, because it occurs as a malignant mutation after birth. It is cancerous in the sense that a characteristic of NHL is the uncontrolled growth of mutated cells derived from normal lymphic tissue. In the case of NHL, a lymphocyte undergoes a malignant change, and then begins to multiply continuously and excessively. Eventually, these mutated cells decrease the number of normal blood cells and create tumors in the lymph node. A tumor is a spontaneous development of abnormal tissue that detrimentally affects the organism. Because NHL attacks the immune system, the body's defense mechanism against harmful contagions, it leaves the person vulnerable to infection. The development of cancerous tumors is often fatal.
Currently, the cause of NHL is unknown. Some doctors suggest that exposure to a virus or bacteria as a result of a suppression in the immune system causes NHL. They consider people who have recently undergone an organ transplant to be at a higher risk of acquiring NHL than others. One disturbing trend in recent years has been that the incidence of NHL has been doubling annually. Some doctors attribute this trend to increased use of herbicides or continued use of dark hair dyes. Another possible cause is the relationship between lymphoma and HIV. Because people with HIV are 50 to 100 times more likely to acquire NHL, it is thought that the increase in the number of people with HIV has escalated the incidence rate of lymphoma.
Although the incidence rate of NHL is 3 out of every 10,000, the chances of acquiring the disease increase with age. Typically, it does not affect people who are under the age of 50. There are approximately 55,400 new cases of NHL reported in the United States each year.
Symptoms
Swollen lymph nodes are the most prominent sign of NHL, although in most cases swollen glands are reactions to infection and not an indication of cancer. This is because when an infection is present, these nodes swell in order to produce the white blood cells (or lymphocytes) necessary to destroy the infection. These nodes are located in the groin, the armpits, and the neck. If they are swollen, they can be hard, lumpy, red, or tender.
Other symptoms of NHL include:
Diagnosis/Treatment
Typically, doctors will suspect NHL if they find enlarged lymph nodes and no apparent explanation for the swelling, such as a recent infection. If they find the lymph nodes swollen and cannot detect any kind of infection, most doctors will perform a lymph node biopsy. In this test, a bit of the lymph system is removed and tested for tissue abnormalities. A biopsy also allows doctors to examine blood cells to determine whether or not the lymphocytes have any abnormalities. A cytogenetic analysis, another method of diagnosis, can reveal chromosomal abnormalities. Knowing the chromosomal abnormalities can help a doctor choose which drugs will work best for treatment.
After NHL has been diagnosed, another series of examinations is used to determine the developmental stage of the cancer, or what is called the "extent of the disease". One way to determine the staging is to examine either the blood or the bone marrow and to see whether or not lymphomatic cells are present. In addition, MRIs, abdomenal CT scans, X-rays, or lymphoangiograms can all be used to figure out if the liver, the spleen, or the kidney are either enlarged or strangely-shaped. During a CT scan, the body is X-rayed from multiple angles. Because the lymphic system often does not appear on X-ray, doctors will sometimes perform a lymphoangiogram in which a contrasting fluid is injected into the system in order to highlight any possible tumors.
Once diagnosis and staging determination is complete, there are five factors that influence decisions regarding treatment. The first factor is the nature of the NHL. NHL is broken down into 5 different categories or classes, ranging anywhere from indolent and slow-moving to aggressive and rapidly-progressing. The second factor is the relative stage of the cancer's development. Treatment measures intensify as the cancerous cells are found to be more widespread throughout the lymphic system. The third factor involves the type of cell, whether B, T, or NK, that the disease is most affecting. The fourth factor determining treatment is to what extent organs outside the lymph nodes are injured. This factor also includes the severity of fevers, sweats, or any weight loss that a person with NHL may be experiencing. The final factor is the age of the person. Advanced age or concurrent medical problems typically necessiates intensified treatment methods.
The purpose of treatment is to eliminate all malignant cells, and to induce a complete remission. As aforementioned, the kind of treatment depends on the stage of development. In most cases where the NHL is considered indolent, the disease simply needs to be observed. Sometimes a doctor will administer a mild cycle of drugs. In the event of remission, the lymphoma usually comes back and will require more powerful drugs for treatment. People with mild NHL can expect to experience a series of remissions.
For more progressive cases of NHL, a doctor will often administer either chemotherapy or radiation therapy. Chemotherapy consists of various combinations of drugs that are usually prescribed for a cyclic duration of 4 weeks. If the NHL is aggressive, sometimes 6-12 cycles are needed. These drugs can be administered continuously or with interruptions, and should be maintained as long as they continue to be effective and tolerable. Certain intense cases of NHL may require high doses of chemotheraphy accompanied by a bone marrow transplant.
The purpose of radiation therapy is to shrink the tumor. A tumor that has been reduced in size can be more easily removed by surgery. It also improves the effectiveness of chemotherapy. Radiation therapy prevents the cell division and multiplication of malignant growths. It is particularly helpful with progressive cases of NHL because response to radiation increases with the rate of cancer cell growth. Although radiation therapy may take longer than chemotherapy, the advantage is that it often does not require hospitalization.
Chemotherapy and radiation therapy can be extremely helpful in treating NHL, and often prove to be vital methods of treatment. However, they can also have injurious side effects. These side effects vary with age, intensity of the cancer, duration, and type of treatment. Radiation therapy can cause myelosuppression, a condition in which there is a serious decrease in the blood cell count. As the white blood cells are decimated, there is an increased risk of infection. This condition usually requires a blood transfusion. Another large risk with radiation therapy is the possibility that the radiation will mutate other cells, resulting in other kinds of cancer. Both chemotherapy and radiation therapy can have oral and gastronomical effects, including vomiting, nausea, mouth sores, blood in urine, constipation, and diarrhea. In some cases, treatment can induce fatigue, fever, coughing, skin rash, hair loss, and nerve function impairment. Another detrimental side effect is the possibility of fertility loss. In some cases, treatment can be complicated by autoimmune hemolytic anemia. This is an abnormality of the immune system that results in natural antibodies forming against and destroying the body's red blood cells. The cause is unknown.
Currently, there is no known means of prevention in regard to NHL. A person who has an indolent grade of NHL has a life expectancy of about 6-8 years. The survival rate of someone with aggressive NHL depends much more on reaction to therapy, with about 30% of those people with a rapidly-progressive disease being cured. While scientists are still far away from a cure, recently there have been rapid advancements in methods of treatment. Monoclonal antibodies are proteins made in the lab, and they have the ability to destroy malignant cells. They are not very toxic, and a recent lab study using rituximab showed that they were able to shrink the tumor in at least half of the cases. Cytokines are a natural product of the cells that have the function of stimulating blood cell production and enhancing the immune system. They can be artificially created in the lab using biotechnology. Other researchers are working on vaccines for NHL. While these vaccines would not be typical in the sense that they would not prevent the disease, but rather induce remission and reduce relapse, they would help the immune system suppress the lymphoma cell.
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