Chemotherapy is the use of medications and chemicals to treat cancer (Anti-cancer medication). It is used to kill cancer cells by preventing their growth, multiplication or spread to other parts of the body. Different types of chemotherapy can damage cancer cells at different points in their life cycle.
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| Chemotherapy is used to prevent the cancerous cells, from reaching stage 5 of their growth cycle and spreading to other parts of the body through the blood stream. |
Chemotherapy is a treatment that uses medicine to weaken and/or destroy cancer cells in the human body. It kills the other cells at the original cancer sire and any other cancer cells that might have already spread to another part of the body. It affects the whole body by going through the bloodstream. Chemotherapy is used to get rid of any cancer cells that may be left behind after a surgery for breast cancer. It also reduces the risk of the cancer coming back. Chemotherapy is also used to shrink the cancer just before surgery, so that the doctors can hopefully get rid of all of the cancer cells. This is especially helpful if the cancer tumour is large.
How it works?
The body is made of millions of healthy cells, genes tell our cells when to divide, how to grow and work, and when to die. However, when mistakes occur in the genetic material of a cell, and the cell begins to rapidly reproduce uncontrollably, the cell changes into a cancerous cell. These cells begin to expand and grow, occupying more and more space , until they eventually take up the space occupied by healthy cells. Chemotherapy is used to interfere with the ability of the cancerous cells to divide and reproduce. The medication used in chemotherapy may be entered into the bloodstream to attack cancerous cells throughout the body, or they can be directed at the area in which the cancer has accumulated.
Although, Chemotherapy, is used to destroy/eliminate the rapid reproduction of cancerous cells, it also damages regular healthy cells, in the process, since it affects the whole body. This may lead to side effects that can be both temporary (in which cells can recover/regenerate/repair) or permanent (long lasting effects.) Usually, healthy cells in the bone marrow, gastrointestinal tract and hair follicles are affected.
1. may attack genetic material of cell.
DNA, or Deoxyribonucleic acid is the material inside the nucleus of a cell that carries genetic info.
2. may cause cells to die by preventing proteins inside the cell from working properly.
RNA, or Ribonucleic acid is a nucleic acid molecule that plays an important role in protein synthesis and other cell activities.
Methods of Chemotherapy:
* Intravenously (in the vein)
* Intramuscular (In the muscle)
* Subcutaneous (under the skin)
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| Intramuscular injections (IM), Intravenous injections (IV) and Subcutaneous injections (SC) |
There are also many other types of injections available for intravenous treatment, such as a catheter, which is soft, flexible tube that is placed in a vein as long as necessary for treatment, where blood samples can be taken, and drugs can be given. As well, there is a port which is a plastic/metal disk that is placed under the skin.
Intramuscular Injections (IM) are given through the skin into the muscle layer of the arm, thigh or buttock.
Subcutaneous Injections (SC) are shots that are given with short needles, which are inserted into the space between the skin and the muscle layer, however it does not enter the muscle layer.
* Orally (by mouth)
Oral Medications are pills, capsules, or liquids that can be swallowed.
Effects of Chemotherapy:
Chemotherapy can affect ALL rapidly growing cells, including cancer cells, and normal healthy cells. The healthy cells that divide rapidly are: blood cells, cells in hair follicles, and cells in the lining of the mouth, stomach and bowels. During the process of chemotherapy, these cells are most likely to be killed/damaged causing side effects to occur to the body. (side effects vary in type and severity for different individuals and depend on the medication that is taken)
Common Side effects:
* Neutropenia (low white blood cell count)
* Anemia (low red blood cell count)
* Thrombocytopenia (low platelet count)
* Diarrhea
* Peripheral Neuropathy
* Alopecia (Hair loss)
* Emesis (nausea/vomiting)
* Mucositis (mouth/throat sores)
* Osteopenia/Osteoporosis (Bone loss)
Neutropenia is when the number of white blood cells that protect us from infections decrease, causing an increase in the risk of infection. It is the most serious side effect of chemotherapy, and may be life threatening if not treated immediately. A low count of white blood cells, causes the chemotherapy treatment to be delayed to reduce further risk of infections. This may change the results of the treatment, since the medication is not taken as often as it should be.
Treatment Options:
CSF (colony-stimulating factor) that stimulates the bone marrow to increase the number of white blood cells. (boosts white blood cell or neutrophil count and reduces infections) However CSF may cause the spleen to enlarge and rupture, which may cause death to the patients receiving the treatment.
Anemia is a common side effect of chemotherapy that affects the ability of the bone marrow to produce red blood cells. As the count of red blood cells decreases, less oxygen is distributed throughout the body causing the patient to experience fatigue, dizziness and shortness of breath.
Treatment Options:
1. Medications to increase red blood cell production
Erythropoiesis-stimulating agents are used to stimulate the bone marrow to make more red blood cells. (this may cause fevers, headaches, muscle soreness, nausea or chest pain)
2. Transfusion (red blood cell replacement)
3. Diet based on high nutrient-value foods
patients can also reduce the affects of anemia, by getting plenty of rest, limiting activities that are unnecessary, keeping things within reach, and having a well-balanced diet.
Thrombocytopenia is a side effect of chemotherapy that affects the ability of the bone marrow to produce platelets, which is a type of blood cell that is necessary to help form blood clots. If the blood does not have enough platelets, it may cause the patient's body to be more susceptible to bruises or bleeding, without even having an injury. A low platelet count may require a platelet transfusion or medications to boost the platelet production in the bone marrow.
Symptoms:
* unexpected bruising
* prolonged bleeding from minor cuts/scratches
* small red spots under the skin
* reddish/pinkish urine
* black/bloody bowel movements
* bleeding from gums or nose
* bad headaches
* increase in weakness
* pain in joints and muscles
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| Diagram of the red and white blood cells, as well as the platelets that occupy, the artery. |
Peripheral Neuropathy is a condition in which the chemotherapy treatment, has caused damage to the body's nervous system. This condition may cause numbness, weakness, loss of coordination or a burning sensation in the hands, feet and lower legs.
Alopecia, (also known as hair loss) is one of the most visible side effects of chemotherapy. the patient's hair may become thinner gradually, or may all fall out at once, this may cause the scalp to become tender and vulnerable. However, the hair usually grows back, with a different texture, colour or curl.
Emesis, which is also known as nausea and vomiting, can be prevented, using anti-nausea medications or anti-emetic medications.
Mucositis, is when chemotherapy treatment, causes the lining of the mouth and throat to become inflamed. This may result in soreness in these areas, causing the patient to have difficulty talking, eating, drinking or swallowing. Good oral hygiene reduces the risk of infection from mouth/throat sores, that are caused by germs that reside in your mouth.
Osteopenia/Osteoporosis, (also known as bone loss), is when chemotherapy, affects the balance of bone destruction and bone renewal that continuously occurs within the body, causing the bones to become thinner, and increase the risk of bone fractures. Severe bone loss can lead to painful fractures in the wrist, spine and hip, resulting in reduced mobility.
Chemicals used in chemotherapy
There are over 300 possible drugs that are used in chemotherapy. They can be categorised into four groups: antimetabolites, alkylating agents, topoisomerase inhibitors and anthracyclines.
Antimetabolites
Antimetabolites disrupts a cancer cell's ability to metabolize food into energy.
6-mercaptopurine and 5-Azacitidine are examples of chemicals that can be inserted subcutaneously(under skin), intravenously (directly into veins), or some may be take orally. Methotraxate, example of chemotherapy agents, works on the S-phase of the cell cycle, where it inhibits an enzyme that is important during DNA synthesis.
Alkylating agents
Alkylating agents prevent cancer cells from reproducing and spreading, by damaging the cancer cell's DNA, and also prevents tumour growth in some cases. Alkyating agents cross-link the DNA strands and causes abnormal base pairing. They are effective during all phases of cell cycle, therefore can be a treatment to various cancers. Examples of alkylating agents used in chemotherapy include cyclophosphamide, abraxane and mechlorethamine hydrochloride , and are usually given intravenously.
Topoisomerase inhibitors
Topoisomerase inhibitors break down the DNA structure of the cancer cell and prevents reproduction by restricting a single helix strand from bonding to another. It works similar to alkylating agents, but attacks at more earlier stages, during actual reproduction. Some common examples consists of CPT-11, Camptothecan and Taxol.
Anthracyclines
They are a class of antibiotic chemotherapeutic agents, and attack cancer cells through multiple mechanisms, preventing replication and damaging cells to cause cell death. These drugs are from natural resources, and restricts the topoisomerase enzyme during the process. Common anthracyclines include Mitoxantrone, Doxorubicin and Daunorubicin.
Chemotherapy scans:
(Pre - chemotherapy and post-chemotherapy scan )
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| http://www.ajronline.org/content/145/4/743.full.pdf |
Fig. 5.-A, Prechemotherapy scan. Psoas-density, 20-cm retroperitoneal nodal mass extends from upper abdomen through pelvis. B, Postchemotherapy
scan. Psoas-density. 1 .5-cm left paraaortic mass (arrows), 1 -cm node adjacent to left psoas muscle (arrowhead), and several nodes measuring 1 cm or less onother sections are only evidence of residual mass. Histology: 1 .5-cm left paraaortic node contained active malignancy. Several smaller nodes were fibrotic. (http://www.ajronline.org/content/145/4/743.full.pdf)
REFERENCES:
- ChemoReady.ca: (2011). What is Chemotherapy. Retrieved on October 26, 2011, from http://www.chemoready.ca/en/understanding/what.jsp
- MediLexicon International Ltd. (2004-2011). What is Chemotherapy? What are the Side Effects of Chemotherapy? Retrieved on October 29, 2011, from http://www.medicalnewstoday.com/articles/158401.php
- The Cleveland Clinic Foundation. (2005). How is Chemotherapy Given?. Retrieved on October 29. 2011, from http://www.chemocare.com/whatis/how_is_chemotherapy_given.asp
- Breastcancer.org. (2009, 10 29). :chemotherapy . Retrieved from http://www.breastcancer.org/treatment/chemotherapy/
- Categories of Chemotherapeutic Agents. (n.d.). Mesothelioma Web – Mesothelioma Cancer Answers. Retrieved October 31, 2011, from http://www.mesotheliomaweb.org/mesothelioma/treatment/chemotherapeutic-agents/
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