Chemotherapy involves the use of a variety of drugs, often in combination, to kill cancer cells or prevent them from multiplying. In truth, chemotherapy does not specifically target cancer cells per se; instead, chemotherapy tends to affect fast-dividing cells throughout the body, of which cancer cells are only one kind. Because of this lack of specificity, chemotherapy drugs also have a very high rate of attack on normal body cells that also divide quickly, such as the cells lining the stomach and intestines, and the cells of the hair follicles. When normal cells are destroyed by chemotherapy, symptoms result (such as nausea and vomiting, or hair loss).
Chemotherapy may be administered systemically or regionally. Systemic chemotherapeutic agents are administered so that they are absorbed into the bloodstream and ultimately circulate throughout the body. Systemic chemotherapy agents may be taken by mouth (orally), administered through a vein (intravenously), or given as a shot (injected). Alternatively, chemotherapy can also be administered regionally; that is, the drugs are infused into a specific area of the body, such as the abdomen (called intra-abdominal chemotherapy) or the spinal fluid (called intrathecal chemotherapy).
- A cell type that is deemed “indolent,” meaning very slow growing and not particularly invasive
- Identification of only a small amount of tumor present (called low tumor burden)
- Absence of symptoms from the lymphoma
In a watchful waiting phase, the physician will follow the individual very closely, by performing physical examinations, blood tests, and specific imaging studies at regular intervals. Some people in this situation may avoid treatment for years, without their disease
A specific chemotherapy regimen may involve a single drug (monotherapy) or multiple drugs. The dosages, treatment schedule, and duration of treatment will depend on the type of NHL being treated, the aggressiveness of the specific cells, how widespread the cancer is, etc. Most chemotherapy regimens are given cyclically, with rest periods between periods of administration. This allows healing time for the normal cells that are disrupted by the treatments, in an attempt to minimize the side effects of the chemotherapy.
- Cyclophophamide or Cytoxan®
- Doxorubicin or Adriamycin®
- Fludarabine or Fludara®
- Dexamethasone or Decadron®
- Vincristine or Oncovin®
- Cytarabine or ara-C
- Eoposide or VP-16
- Ifosfamide (Ifos®)
- Bendamustine or Treanda®
- Pralatrexate or Folotyn®
As mentioned, combinations of more than one type of chemotherapy drug can be combined into a “cocktail.” Using several different types of drugs together means that different chemical mechanisms are employed, increasing the efficacy of the treatment. Common combinations include:
- CHOP: Cyclophosphamide, doxorubicink, vincristine, and prednisone
- HyperCVAD: Fractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone
- FC: Fludarabine and cyclophosphamide
- COMLA: Cyclophophamide, vincristine, methotrexate, leucovorin, and cytarabine
- CVP: Cyclophophamide, vincristine, and prednisone
- DHAP: Dexamethasone, cisplatin, and cytarabine
- ESHAP: Etoposide, methylprednisolone, cytarabine, and cisplatin
- PROMACE-CYTABOM: Prednisone, doxorubicin, cyclophosphamide, etoposide, cytarabine, bleomycin, vincristine, methotrexate, and leucovorin
- ICE: Ifosfamide, carboplatin, and etoposide
Chemotherapy Side Effects
Because chemotherapy drugs are not very specific in their effects, they often kill or damage all fast-dividing cells in the body, not just cancer cells. Some of the side effects of chemotherapy treatments include:
- Nausea, vomiting, and diarrhea: These symptoms can occur when the cells lining the gut (stomach and intestines) are injured or destroyed. Luckily, treatments for nausea and vomiting have greatly improved over the years, and many people are pre-treated (given medications that can effectively prevent the onset of nausea) prior to receiving chemotherapy.
- Stomatitis: Damage to the cells lining the inside of the mouth can cause severe and painful mouth sores, which may be treated with a variety of mouthwashes. Many of these contain local anesthetics (such as viscous lidocaine) to dull the discomfort of these sores, and allow the individual to continue eating and drinking with minimum pain.
- Hair loss or alopecia: Damage to the quick-dividing hair follicles can cause hair loss, which may range from thinning of the hair to complete baldness throughout the course of the chemotherapy. Hair will regrow after chemotherapy is discontinued.
- Easy bruising and bleeding: Because chemotherapy agents attack the fast-dividing cells of the bone marrow, a low platelet count may result. This can cause bleeding gums, for example, or more serious bleeding and bruising. Most people receiving chemotherapy are given regular blood tests to monitor their platelet levels. If they dip down to a dangerously low level, platelet transfusions may be required.
- • Anemia: Again, low red blood cells may occur when the fast-growing cells within the bone marrow (where red cells are produced) are destroyed. Depending on the severity of the anemia, individuals may note severe fatigue and weakness. Red cell transfusions may be given if the red blood cell counts fall too low. Additionally, some individuals may be given injections of Epoetin alpha (Procrit®) to help stimulate red blood cell production by the bone marrow, in an effort to avoid anemia.
- Immunosuppression: When chemotherapeutic agents attack the bone marrow, white blood cells are also affected. With fewer circulating white blood cells, individuals may become very prone to illness and infection. What might be only a minor illness in an individual with a normal immune system can quickly become life-threatening in someone receiving chemotherapy. For this reason, individuals on chemotherapy are advised to avoid situations in which they are exposed to infections (including viruses, bacteria, and fungi). NHL patients are also very carefully monitored for signs of infection. Medications such as granulocyte colony-stimulating factor (filgrastim or Neupogen®) may be given in an effort to prompt the bone marrow to produce more white blood cells.
- Tumor lysis syndrome: This side effect may occur in individuals who have a lot of lymphoma cells. When chemotherapy damages or kills a large number of cells at one time, the large volume of cancer cell byproducts circulating within the bloodstream can be too great for the kidneys to handle. If these substances accumulate within the blood, they can damage the heart and the nervous system. Damage to healthy tissues can be averted through the use of drugs (sodium bicarbonate, allopurinol, and rasburicase), as well as large volumes of fluids.
Because chemotherapy agents can damage other organs, it is often necessary to have periodic blood tests or other screening exams to be sure that the chemotherapy is not injuring the liver, kidneys, or heart.
In certain cases, very high dose chemotherapy may be administered in order to better eradicate cancer cells. Because chemotherapy drugs at these doses are very toxic to the normal blood-forming cells within the bone marrow, this often requires “rescue” with a stem cell transplant (stem cells are early, primitive blood cells that can differentiate into any of the normal cellular components of blood, e.g. red blood cells, white blood cells, or platelets). In many cases, the individual’s own blood stem cells are banked and saved, prior to the administration of the chemotherapy. These stem cells are then infused back into the individual after the chemotherapy regimen has destroyed the bone marrow. In other cases, stem cells from matched donors may be used to replenish the stem cells.