Lymphoma, any one of several cancers that begin in the lymphatic system, has been called one of the “most curable” forms of cancer in the world.
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How Does Lymphoma Work?
To understand lymphoma, we’ll first have to cover the lymphatic system, a network of organs and vessels that carry lymph, a colorless fluid, throughout the body.
You Probably Don’t Know Much About Lymph, But It’s Everywhere.
Lymph is actually everywhere in your body, all the time, and every cell, organ and body tissue is bathed in the stuff. So where does it come from?
It comes from your blood. Blood flows through your circulatory system, carrying oxygen, proteins, blood sugars and white blood cells to your organs, body tissues and ultimately, the cells of from which these structures are made. But blood vessels, like capillaries, don’t work like a syringe does, leading directly inside the cells that need nourishment. Instead, they run past the cells.
Capillaries, though, are porous and blood plasma, a clear fluid that holds all the oxygen, proteins, sugars and white blood cells, leaks out from the blood vessel. This blood plasma then comes to bathe the surrounding cells in nourishment. Red blood cells are too big to get through the capillary walls, so they stay within the blood vessel.
The Lymphatic System: Filtering Toxins, Destroying Foreign Cells
Here’s where the lymphatic system comes in. After the blood plasma has done its job, “feeding” the cells, it has to go somewhere. Vessels and capillaries of the lymphatic shadow, like a shadow version of the circulatory system, pick up the fluid and start carrying it away from the cells. The fluid also gets a name change at this point; once it’s entered the lymphatic system, we start calling plasma “lymph.”
Eventually, the lymph fluid reaches a lymph node, one of about 100 bulges that stud the network of lymph vessels. These nodes filter toxins and waste materials out of the lymph fluid. They also create lymphocytes, specialized white blood cells that can tell the difference between normal healthy cells and dangerous foreign ones, and destroy the invaders. When you get an infection, your lymph nodes often swell, because they’re being swarmed by billions of white blood cells trying to kill off the foreign cells.
Once the lymph is filtered, and cleared of foreign cells, it returns to the blood stream, mostly through two large ducts in your neck. That, in brief, is the lymphatic system.
Lymphoma: A Basic Definition
Lymphoma starts when some of those white blood cells transported in lymph fluid, the lymphocytes, become abnormal, mutating and beginning to divide uncontrollably. In most patients, these abnormal lymphocytes will come to collect in a lymph node, forming malignant tumors.
Before we go any further, it’s important to distinguish between the two basic forms of lymphoma: Non-Hodgkin lymphoma and Hodgkin lymphoma.
Hodgkin & Non-Hodgkin
Hodgkin lymphoma, according to the Dana-Farber Cancer Institute, starts in a specific type of lymphocyte, B cells, which in a patient with lymphoma will present as something called “Reed-Sternberg” cells. Reed-Sternberg cells are abnormally large and have more than one nucleus. Non-Hodgkin lymphoma, on the other hand, can start in either B cells or another type of white blood cell, T cells.
Both types of lymphoma can cause lymph nodes to swell, although this is normally painless. But Hodgkin lymphoma, which is far more common among US patients, tends to arise in the lymph nodes of the neck, chest or underarms, while Non-Hodgkin lymphoma can start in lymph nodes throughout the body, and even other organs.
Hodgkin lymphoma, or Hodgkin’s disease, tends to follow an orderly progression, advancing from one group of lymph nodes to the next. Non-Hodgkin lymphoma is less predictable, and usually diagnosed at a later stage than Hodgkin’s.
While early symptoms, most notably swollen lymph nodes, can suggest the presence of disease, a form of biopsy is usually considered necessary to actually diagnose lymphoma. In a biopsy, doctors will remove all or part of a lymph node, and send the tissue off to a pathologist for close inspection. Bone marrow can also be extracted, using a needle, for similar scrutiny. In either case, pathologists are looking for abnormal cells.
Blood and imaging tests can be used to support the need for a biopsy, or suggest treatment methods after an initial diagnosis, but cannot replace the accuracy of studying cell structures under a microscope. Symptomatic findings, on the other hand, can be misleading, since the early signs of lymphoma closely resemble the symptoms of other conditions.
Non-Hodgkin lymphoma, specifically, has a high misdiagnosis rate due to its “nonspecific” symptoms.
Physicians use numerous types of cancer treatments to tackle lymphoma. Some of these techniques will be familiar, while others are radical and still being explored. The best choice of treatment depends on the type of lymphoma being treated, how far it has spread and other medical conditions that may be present.
Chemo & Radiation
Chemotherapies are still very common, especially for patients with Hodgkin lymphoma, and often followed by radiation therapy directed toward affected lymph nodes.
Chemotherapeutic drugs are chemicals that kill off rapidly-dividing cells, both cancer cells and healthy ones, like hair and mouth cells, a systemic (or “untargeted”) effect that usually leads to chemotherapy’s infamous, and undesirable, side effects. Not all chemotherapy is administered orally, however, and many patients with Hodgkin’s disease are given the drugs through a catheter inserted beneath the skin.
Radiation, on the other hand, is a localized treatment that focuses a high-energy beam directly at cancerous tumors. The energy breaks down the DNA inside cancer cells, preventing them from dividing further. While we now have techniques for targeting radiation even more, like pellets that can be implanted inside the body, patients with lymphoma almost universally receive radiotherapy from an external machine.
Stem Cell Transplants
For most patients, chemotherapy and radiation will be the first-line treatment. But chemo can have unwelcome side effects, and higher dosages may kill off healthy bone marrow cells, which serve as a key production facility for both red and white blood cells. Some patients will undergo a stem cell transplant, in order to replace the healthy cells that have been lost.
Stem cells (specifically “hematopoietic” stem cells) are very immature cells, ones that can develop, or differentiate, into any one of the more specialized blood cells that our bodies rely upon. In a stem cell transplant, doctors will take an amount of these immature cells and reintroduce them into a patient’s body. Ultimately, the transplanted stem cells will make their way to the bone marrow, differentiate and replace those white and red blood cells that were destroyed by chemotherapy.
Newer treatment techniques, collectively known as “immunotherapy” or “biologic therapy,” seek to harness the body’s own immune system, training it to better identify cancer cells and kills them. Some of these treatments boost the white blood cells already in your body, while others introduce entirely new, laboratory-designed cells that can seek out and destroy lymphoma cells with unmatched precision.
To learn more about this exciting area of research, click here.
Are We Good At Fighting Lymphoma?
Today, our ability to treat lymphoma is extremely refined, and the success with which we’ve met the challenge of lymphoma is nearly unrivaled by any other domain of cancer research. As we mentioned earlier, this is often cited as the “most curable” form of cancer.
But that wasn’t always true. Between 1960 and 1963, the 5-year survival rate among white patients (the only data we have for that time period) with Hodgkin lymphoma was around 40%. Today, and including patients of any race, the 5-year survival rate has more than doubled, to 88.3%, according to the Leukemia & Lymphoma Society. This change has been even more promising for younger patients. More than 94% of patients diagnosed with Hodgkin lymphoma under the age of 45 will survive at least 5 years.
Similar improvements have been observed among patients with Non-Hodgkin lymphoma. From 1960 to 1963, only 31% of white patients could expect to live more than 5 years after their diagnosis. Now, nearly 72% of patients, regardless of race, will survive longer than that.