Chemotherapy: The Facts

What is Chemotherapy?

Chemotherapy is the treatment of cancer with drugs, hormones, and other biological substances that can destroy cancer cells. How does Chemotherapy Work? Surgery and radiation therapy remove, destroy or damage cancer cells directly in a specific area. Chemotherapy, on the other hand, works throughout the body. Its goal is to destroy cancer cells wherever they may be, even if they have spread to parts of the body far from the primary (original) tumor site. Chemotherapy destroys cancer cells by interfering with their growth, by preventing them from reproducing, and in some cases, by inducing the cell to program itself to die (apoptosis). Over the years it has been found that chemotherapeutic agents when given in carefully designed sequence or together may be more effective than when the same drugs are given separately.

Chemotherapy may be used for the treatment of cancer as the only treatment as in many cases of lymphoma. More frequently it will be given in combination with surgery and/or radiation. The chemotherapy may be used to shrink a tumor so that the surgeon can be more likely to remove it completely. Chemotherapy can also be given to enhance the cell destroying effects of radiation. Frequently it may be given after surgery to insure that any residual cells in the original tumor site or microscopic deposits elsewhere will be destroyed even before a recognizable tumor deposit can be found.

The drugs used in the treatment of cancer have been carefully developed through years of research. They are first tested against cancer cells in the laboratory and then in animals bearing transplanted human tumors. Only one in a thousand chemicals tested in this fashion is found to be sufficiently active to warrant being tested further in humans, in which case a clinical trial would be developed. The entire process of discovery from the initial laboratory studies to the completion of acceptably valid clinical data can take as long as 10 years. Sufficient information must be accumulated and submitted to the Federal Drug Administration (FDA) before approval for use in clinical medicine can be given.

In addition to chemicals that are manufactured in the laboratory or extracted from plants and then recreated in the laboratory, many biological materials have been found to have anticancer effects. Most noted are hormones which have been known to be effective against breast cancer since the early 1900s. During this long period of time hormonal treatment has been perfected and the basis of its action on specific kinds of breast cancer have been discovered. In men, male hormone has been known to affect prostate cancer since the 1940s. Treatments designed by adding female hormones or removing male hormones are frequently part of standard clinical practice today. Newer agents are being developed all the time based upon an increasing knowledge of the molecular structures within the cell that can be targets for new compounds that interfere with the cell's ability to grow and reproduce itself, sparing the rest of the body of other side effects.

New anticancer agents have been developed which do not destroy cells directly. They have their effect by interfering with the blood supply to tumors, starving the cancer cells which then proceed to die. These anti-angiogenesis agents are now in clinical trials.

Side Effects of Chemotherapy

It is well known that cancer cells grow and divide more rapidly than normal cells and most anticancer drugs are designed specifically to destroy growing cells. Normal healthy cells also grow and multiply and some more quickly than others. The chemotherapy agent targeted for cancer cells, therefore, can also affect these cells. This results in damage to healthy tissue which is one of the main side effects of chemotherapy. The extent of these effects on normal tissue varies depending upon the type of drugs that are used and how the body reacts. Over time, normal cells will recover and continue functioning; cancer cells die off. Medical oncologists (the doctors who specialize in giving chemotherapy) can explain the side effects that are most likely to occur with the agents which are to be used and can prescribe medications to help with these side effects.

• Nausea and vomiting - a common side effect of chemotherapy is nausea and vomiting which may be controlled or lessened by a wide range of medicines which your doctor can prescribe. It is sometimes helpful to eat several small meals throughout the day rather than large meals at any one time. Avoiding fried or fatty foods can also help.
  
  
• Fatigue - feeling tired and lacking energy is the most common symptom reported by cancer patients. The exact cause is not always known. It may be due to the disease, chemotherapy, radiation, low blood counts, lack of sleep, pain, stress, poor appetite, along with many other factors. The most important thing to remember is to listen to your body. If you feel tired, take a rest. Usually, the feeling will pass in a ½ hour to an hour and you will be able to continue with your usual activities. Balancing periods of rest with light exercise helps speed recovery and prevents muscle wasting that can result from too much bed rest.
  
  
• Anemia - Because chemotherapy can affect the bone marrow and the body's ability to produce red blood cells, it may cause a condition called anemia which can make you feel weak and tired. If anemia becomes a serious problem and it limits continuation of cancer treatment, transfusions may be necessary. New drugs have been developed (erythropoitin based) which can stimulate red cell formation.
  
  
• Chemotherapy can also affect the blood cells which are important to stop bleeding. These are called platelets and a drop in platelets can cause bruising and bleeding. In many instances if this becomes particularly dangerous platelet transfusions are given. Most often delaying further chemotherapy will allow the platelets to recover and treatment can then continue.
  
  
• Other blood cells affected by chemotherapy are the white cells which protect you from infection. When these become very low or disappear, patients are prone to pick up the colds and flu of people around them, or more serious infections with bacteria and fungi that would under ordinary circumstances would not have been a problem. Careful monitoring of the blood count during chemotherapy is essential.
  
  
• Hair loss - Loss of hair can occur on all parts of the body not just the scalp. Not all drugs cause hair loss. The hair may become thinner or may fall out completely. In almost all cases the hair grows back after therapy is completed, sometimes of a different texture and very rarely of a slightly different color. In many instances hair can start to return while treatments are still being given. Many patients wish to wear a wig until the hair returns. Call the Rhode Island Cancer Council at (401) 728-4800, visit our Wig Directory, or email us for sources of wigs.
  
  
• Fertility - Many chemotherapy compounds can induce menopause in a woman who is still in the childbearing age. In some cases cessation of periods may be temporary, but in others it will be permanent. In men, some chemotherapy will destroy the cells that produce sperm. This may be temporary or permanent. If questions of future parenthood are relevant and important, you should speak to your Medical Oncologist before starting chemotherapy about preserving ova (eggs) or sperm banking if questions of future parenthood are relevant and important. These are individual decisions and should be worked out before treatment is initiated.
  

For Medical Oncologists practicing in the State of Rhode Island, please check our Oncologist database at: http://www.ricancercouncil.org/resources/oncologists.php

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