What is chemotherapy?
Chemotherapy is the use of chemical substances to treat disease. It most often refers primarily to the drugs used to treat cancer. Cancer is the uncontrolled growth of cells coupled with malignant behavior: invasion and metastasis
Other uses of chemotherapy agents that affect the function of immune cells are for the treatment of autoimmune diseases such as multiple sclerosis and rheumatoid arthritis. These type of diseases arise from an overactive immune response of the body against substances and tissues normally present in the body – in other words, the body attacks its own cells.
Why? Because non-cancer diseases such as MS or arthritis are not related to the “uncontrolled” cell multiplication characteristic of cancer. Thus, chemotherapy directed toward these diseases does not include agents that affect cell growth and multiplication. Instead, the drugs affect the function of certain types of immune cells.
Chemotherapy agents are also used in the suppression of transplant rejections, which occur because a normal healthy human immune system can distinguish foreign tissues and attempts to destroy them.
What are the benefits of chemotherapy?
Chemotherapy is the most effective single agent treatment for some types of cancer, offering the best opportunity for cure, remission, or palliation. The goal of chemotherapy is to cure the condition and when the condition can not be cured, to balance the potential benefits of chemotherapy with quality of life. Most cancers are treated by chemotherapy.
Why: Cure and palliation are more common outcomes than remission. Palliation refers to a condition that can be improved with treatment, but not cured.
Chemotherapy is often used in the post-operative setting, to kill any remaining cancer cells that have evaded surgery or to prevent the spread or metastasis of the cancer after surgery.
Chemotherapy can be used in conjunction with radiation therapy. In some instances chemotherapy can actually help the radiation kill cancer cells, such as in the treatment of cancer of the tongue. In other instances, the chemotherapy is used to kill metastatic cells (cells that have spread from the original tumor to other parts of the body), while the radiation is used to kill the local tumor.
Chemotherapy can also be used to treat some cancers that are not amenable to surgery or radiation therapy. In most cases, chemotherapy is used to improve the quality of life.
Chemotherapy may be given with a curative intent, to prolong life, or to reduce the severity of symptoms.
Do I have to have a port?
I chose not to have a port or PICC line, but your decision should be made, as mine was, with your doctor. Here’s the skinny on how it all works:
Chemo drugs can be given in a variety of different ways. Intravenous administration is the most common method for delivery of cancer drugs, because most of these drugs require frequent administration and are easily absorbed through the bloodstream. In the case of multiple sclerosis and rheumatoid arthritis, frequent treatments are given subcutaneously (MS, arthritis) and orally (arthritis). When short term steroids are given, the IV is not through a port or PICC line, but through an arm vein.
The PICC line (peripherally inserted central catheter) may be inserted into a peripheral vein, such as the brachial vein in the arm, and then advanced through increasingly larger veins. The port (or port-a-cath) is placed under the skin on the chest, and the catheter is then threaded into a larger vein that supplies the heart. The port can be felt under the skin and the nurse can find the entrance by locating the edges of the port and inserting a special needle into the soft middle section. (Hey, it’s your body, the more you know what they’re doing to it, the less you’ll be afraid.)
Another use of the port beside medication delivery is for blood withdrawal, eliminating the need to draw blood from the arm. The port allows the medication to be given over a longer time than a PICC line, which must be changed intermittently to avoid infection. Other reasons cancer chemo (and sometimes long courses of nutrition and antibiotics) is given through a PICC line or port are to avoid vein collapse, and lessen the risk of blockage with frequent infusion.
What are the side effects of chemotherapy?
The treatment can be physically exhausting for the patient. Current chemotherapeutic techniques have a range of side effects mainly affecting the fast-dividing cells of the body. Common side-effects include (dependent on the agent):
How is chemotherapy dosage determined?
Correct calculation of the dosage of chemotherapy is of utmost importance: if the dose is too low, it will be ineffective against the tumor, while at excessive doses the side effects will be intolerable to the patient. This has led to the formation of detailed "dosing schemes" in most hospitals, which give guidance on the correct dose and adjustment in case of toxicity.
In immunotherapy (treatment of disease or disorders by strengthening the body’s immune system, for example, by administering antibodies), they are in principle used in smaller dosages than in the treatment of malignant diseases.
In most cases, the dose is adjusted for the patient’s body surface area (BSA), a calculated value obtained from the patient’s weight and height, rather than by direct measurement. For many drugs, dose is adjusted by body weight. For cancer chemo, BSA is a better indicator to adjust drug dose than body weight because it is less affected y mass due to fat (which may be unrelated to drug metabolism).
How are chemotherapy drugs delivered?
In cancer patients, most chemotherapy is delivered intravenously, although there are a number of agents that can be administered orally.
In some cases, isolated limb perfusion (often used in melanoma), or isolated infusion of chemotherapy into the liver or the lung have been used. The main purpose of these approaches is to deliver a very high dose of chemotherapy to tumor sites without causing overwhelming systemic damage.
Depending on the patient, the cancer, the stage of cancer, the type of chemotherapy, and the dosage, intravenous chemotherapy may be given on either an inpatient or outpatient basis. For continuous, frequent or prolonged intravenous chemotherapy administration, various systems may be surgically inserted into the veins to maintain access. Commonly used systems are
These have lower infection risk and abolish the need for repeated insertion of tubes.
Harmful and lethal toxicity from chemotherapy limits the dosage of chemotherapy that can be given. Some chemotherapy drugs have “lifetime dosage” limitations, because exceeding the prescribed dose can be fatal to the patient.
Anti-rejection medication for people who have received organ transplants, is given orally.
What is "chemo brain"?
A considerable number of patients report fatigue or non-specific neurocognitive problems, such as an inability to concentrate, “walking around in a fog”, irritability, etc. This cognitive impairment can begin during, or appear after treatment. Because symptoms are hard to distinguish from certain aging or menopausal phenomena, “chemo brain” doesn’t lend itself well to scientific study. It happens, though, you’re not imagining things. And in time, it will most likely diminish or disappear.
Why do I have to know all this technical/scientific/medical information about the drugs I’m taking?
You don’t have to know. Presumably, your doctor knows. But one good reason to know is to be able to ask questions.