NHL is broadly divided into two major groups: B-cell lymphomas (which develop from abnormal B-lymphocytes) and T-cell lymphomas (which develop from abnormal T-lymphocytes). The NHLs encompass over 29 types of lymphoma, distinct because of the type of cancer cells in each.
What causes NHL is still unknown. The incidence of NHL has continued to increase over the years. Since the 1970s, the number of people diagnosed annually in Canada has almost doubled. NHL represents the fifth most common malignancy diagnosed in men and the sixth most common in women, with the incidence being approximately 39% higher in men. NHL is not contagious and the patient does not pose a risk to others in any way.
It is important to note that if you have one or more of these risk factors, it does not mean that you will get NHL. In fact, most people with risk factors never develop cancer. Many who are diagnosed have no identifiable risk factors.
The exact causes are unknown. Doctors often cannot explain why one person gets NHL and another does not. We do know that lymphomas are not caused by an injury and that you cannot get NHL by being in contact with someone who has the disease.
Children born with abnormal or deficient immune systems have an increased chance of developing NHL during childhood or as young adults.
There has been recent progress in understanding how DNA may play a part in causing normal lymphocytes to become cancerous. Cancers can be caused by DNA defects (mutations), which cause genes that direct cell growth (oncogenes) to overproduce or genes that slow growth or promote cell death (tumour suppressor genes) to fail. Some DNA mutations can be inherited, increasing a risk for certain types of cancer, but NHL is NOT one of the cancers caused by these inherited gene mutations.
Unfortunately, the bottom line is that most patients with NHL have no known risk factors, therefore the true cause of NHL is still unknown. However, it is important to note that NHL is NOT contagious so patients pose no health risk to others at any time and possessing a risk factor does not mean a person will develop NHL.
NHL is medically diagnosed by taking a tissue sample (biopsy). A needle biopsy is sometimes used but a surgical biopsy, removal of a whole node, is preferred in getting enough tissue for a definite diagnosis. The pathologist (a person trained in the biology of cells) searches for cancerous cells, and will confirm a diagnosis of NHL.
Other tests your medical team may perform include:
Certain medical centres may perform additional tests, including exploratory surgery to determine the extent of the disease, or a lymphangiogram, a procedure during which a radio-opaque liquid is injected into the lymph system through the feet; the fluid travels throughout the lymph system and remains visible for up to six months on x-rays.
Once NHL is found, more tests will be done to find out the exact type or classification, whether the cancer has spread from where it started to other parts of the body (i.e., the staging of NHL), and the aggressiveness of the tumour (i.e., the grading of NHL).
The exact type, or classification, of NHL is important to determine, as this helps doctors decide on the most appropriate treatment. The biopsy procedure is critical in the classification process as it provides cells taken directly from the tumour in order for doctors to determine which type of cell the tumour originated from (B-cell or T-cell), as well as other important information about the tumour cells. B-cell lymphomas are far more common than T-cell lymphomas. The biopsy procedure is performed by a surgeon and the cells are examined under a microscope by a pathologist to determine if cancer is present. The biopsy is often called a tissue diagnosis (meaning the diagnosis is made through an examination of the tissue or cells) and the course of the patient’s treatment depends on these results.
Once the surgeon has performed the biopsy and the pathologist has examined the tissue and recorded the information about the tumour cells, they must then use this information to determine the exact type of NHL. The classification process is a complicated one. Many organizations have attempted to simplify the classification process and develop a standardized international classification system for NHL. The most commonly used system is the World Health Organization (WHO) lymphoma classification system, which allows different NHL types to be classified in a standardized way among doctors around the world. Once the NHL type, or classification, has been determined, it is then important to determine the stage and grade of the NHL.
The most common method for staging NHL is called the Ann Arbor Staging System, which can be summarized as follows:
Staging lymphoma
The doctor must also determine the grade of the tumour. The grade of the tumour provides information on how aggressive the tumour is and helps predict how the tumour will behave. This information helps determine the aggressiveness of the treatment approach. The grade is determined by the appearance of the cancer cells, what unique characteristics they have, how they function and how quickly they grow and divide. The grade is referred to as low-grade, intermediate-grade or high-grade NHL. Low-grade NHLs are often called indolent, or slow-growing NHLs. Intermediate and high-grade NHLs are often called aggressive, or fast-growing NHLs. Review the Treatment section for detailed information on how indolent and aggressive lymphomas are treated.
The following table summarizes the specialized process of classifying, staging and grading NHL:
As mentioned earlier, the most commonly used method for classifying NHL is the WHO Classification of Lymphoid Malignancies.
The major goals of NHL treatment include:
NHL often responds very well to modern treatments. This does not mean that NHL is always curable but it does mean that treatment can often provide long cancer-free periods, reduced symptoms and improved quality of life for many patients. Each patient responds differently to treatment, as does each NHL type. The International Prognostic Index (IPI) does give statistically valid estimates of which patients are most likely to relapse, and which patients are less likely to relapse.
This section is now in the process of being developed.
For supportive information please go to either of the following websites: Young Adult Cancer Canada Livestrong Young Adult Alliance
Children
Cancer in children behaves differently than cancer in adults. When children are first diagnosed, they frequently have a more advanced stage of cancer. Eighty per cent of children with cancer show that it has spread to distatn parts of the body, compared with only about 20% of adults. While adult cancers are often attributed to lifestyle choices such as smoking, diet and occupation, childhood cancers have no such known causes and do not attack the same body parts as adult cancers.
In gneeral, it's important to remember that the entire family is affected when a child develops cancer, and everone in the family with have a special need for care and education. Because of these needs, it is highly recommended that you seek treatment from a cancer care centre that specializes in children with cancer. These may be found at major children's hospitals, university medical centres and Comprehensive Cancer Centres. The facilities can provide the entire family with education and support from a team of child care specialists. Childhood cancers require more than just pediatric oncologists - nutrionists, social workers, child psychologists and other work together to care for your family.
Symptoms do exist for NHL but they are not specific. Often a lymph node swells, especially in the upper body area. Other times one feels a lack of energy. More serious symptoms can include weight loss, fever, night sweats or unexplained itching.
NHL is medically diagnosed by taking a tissue sample (biopsy). A need biopsy is sometimes used but a surgical biopsy, removal of a whole node, is preferred in getting enough tissue for a definite diagnosis. The pathologist (a person trained in the biology of cells) searches for cancerous cells, and will confirm a diagnosis of NHL.
Click here to review pathology slides of NHL biogpsy samples
Once childhood NHL is found, more teste will be conducted to find out if the cancer has spread from where it started to other parts of the boyd. This is called staging. Your child's doctor needs to know the stage of the disease to plan treatment.
The following stages are used for childhood NHL:
Childhood cancer cells tend to reproduce and grow more rapidly than most adult cancer cells. Therefore, even though the cancer appears to be contained to one tumour or swollen gland, it has almost always spread beyond its origin. In order to kill all the lymphoma cells present throughout the body, a systemic treatment plan of chemotherapy is the preferred method. Fortunatly, because their cells are multiplying so quickly and chemotherapy drugs target rapidly growing cells, children tend to respond better to chemotherapy than adults.
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