About Chemotherapy

By: Sankave Muraleetharan, Kezia Thaneswaran, Nawshin Nazat

Purpose of Chemotherapy

The purpose to chemotherapy is to destroy and kill cancer cells. It involves toxic drugs to eliminate the cancer cells. Chemotherapy is used as a treatment for cancer patients, which will result in no further tumors to develop. It can also stop the rapidly growing cancer cells, or slow them down. This works along with surgical treatment, biological treatment/therapy and radiation therapy. Biological therapy, also called immunotherapy, is also a form of treatment for cancer. It involves products that are naturally produced from our bodies. This form of treatment stimulates the immune system, which will force the body to act and fight against the disease, either directly or indirectly. Both chemotherapy and biological therapy work together, which will result in less side effects, eliminating cancer cells or stopping the growth of cancer cells, and an easygoing process for the patient.

How does it work?

Chemotherapy is a treatment for cancer that uses different types of drug, to kill the cancer cells that are inside a person’s body.  This type of treatment is worked by preventing and reducing the progress of cancer cells. Cancer cells are cells that divide uncontrollably, that would eventually create a tumor and that tumor will get bigger and would spread to the rest of the body. Chemotherapy can cure cancer, control cancer and even ease a cancer symptom that is also known for palliative care.

It is known that chemotherapy is the only cancer treatment that is used. In other hands, cancer can be treated with surgery, radiation therapy or biological therapy. It is used to make smaller tumor just before a surgery or a radiation therapy is going to occur. It is referred to be known as neo-adjuvant chemotherapy. Chemotherapy helps destroy the cancer cell that is being reproduced and could continue after surgery or radiation therapy had happened. This is known as adjuvant chemotherapy. Radiation therapy and Biological therapy is being helped by chemotherapy in order for this to work better. Chemotherapy also eliminates cancer cells that have returned or also eliminates cancer cell that had spread to other parts of the body. 

The doctors determine which type of chemotherapy drug to use on patients regarding on the type of cancer the patient has. There are chemotherapy drugs that are used for several different types of cancer and some drugs that are only specified for one or two types. Also, chemotherapy drugs can be determined by if you had chemotherapy before or if it is the patients' first time. Another fact is that, if the patient has health problems such as heart disease, diabetes and many more.

Chemotherapy can be given to a patient in several ways, such as Injection. The chemotherapy drugs can be given by a shot in the muscles that are in your arms, thighs, hips, legs, or belly. Intra-arterial is another way, the chemotherapy will go directly into the artery where the cancer cells are. Intraperitoneal is when the chemotherapy goes directly into the area that consists of the organs, intravenous is when it goes directly into a vein. Topically is when the chemotherapy comes as a cream product that you can apply by rubbing onto your skin, and orally is when chemotherapy is produced as pills, capsules, or liquids that you may swallow

Video

Chemotherapy - Virtual Medical Centre

A video that discusses about chemotherapy. 

Types of Chemotherapy

There are different types of chemotherapy. One type of chemotherapy is called alkylating agents. This drug harms the DNA from preventing the cancer cells to replicate. This drug works in all stages in the cell cycle. This type of drug is only used for cancers like, lymphoma, lungs, Hodgkin disease, breast, leukemia, multiple myeloma, sarcoma and ovary. Due to the fact that this drug damages the DNA, this can affect the bone marrow for a long period of time. Platinum drugs sometimes are assembled with alkylating agents since both methods kill cancer cells in a comparable method.

Another type of chemotherapy is antimetabolites. In this method, the DNA interferes with the drugs and the RNA is being replaced by the growth to get the normal building blocks of the DNA and RNA. This method causes damages for the cell during the S phase in a cell cycle. This treatment treats ovary, leukemias, breast and many more.

Anthracycline is another type of method. But in this method, it is mostly referred as an anti-tumor antibiotic. In this treatment, it is interfering with the enzymes that are elaborated in the DNA duplication. This drugs works in all stages of the cell cycle. If this drug is given in high doses, then it can permanently damage the heart. Other types of antibiotics are Actinomycin-D, Bleomycin and Mitomycin-C.

Topoisomerases is an enzyme that helps split the strands of the DNA, so that they can be duplicated. This is used to cure certain leukemias, ovarian, gastrointestinal, lungs and other types of cancers. There are two types of topoisomerase. Examples for the first type would be topotecan and irinotecan. Examples for the second type would be teniposide, etoposide (VP-16) and mitoxantrone. Doing treatment for type 2 can bring back cancer again for the second time and can come back 2 to 3 years after this drug is taken.

Mitotic inhibitors are another type of method where this drug is usually planted alkaloids and other types of compounds resulting it from natural products. This method can break or end mitosis or even inhibit enzymes by producing proteins that are needed for the cell reproduction.  This works during the M phase but it can also harm cells in all the other phases in a cell cycle. Cancers that can be treated with this drug would be lymphomas, lung, myelomas, breast and leukemias. This drug is considered to cause nerve damage that can be considered to be a side effect of dose-limiting.

There are many different types of drugs for chemotherapy. The list above states some of the chemotherapy treatments that people use often. 

Ethical issues

There are several ethical issues that are associated with chemotherapy, such as
1. One important ethical issue is that, there is no point for patient to proceed with chemotherapy, when the cure is unrealistic, because in this case there is no evidence, that the chemotherapy is helpful. This might make patients hesitant about going through with the procedure because maybe it’s not worth all the side effects that come with chemotherapy for a very large large of the chemotherapy not working.

2. Another issue might be that some of the drugs used for chemotherapy might have been tested on animals, which becomes an ethical issue due to animal rights and whether or not it's appropriate, especially if the animal never had cancer in the first place.

3. Another ethical argument that may come up would be if it is beneficial for a patient to go through a harsh course of treatment, especially if the treatment will not do much for the patient, so will the risks outweigh the benefits? And is it really worth taking the chance to live a longer life, for an enormous amount of pain that may or may not slow down the disease and comes with side effects?

4) Lastly, another ethical issue would be whether or not the chemotherapy will do more damage to your health that the cancer would have if it was left untreated. If the chemotherapy does not increase one’s chance of having a longer life span and better quality of life, they might as well have left the cancer untreated. It is also very expensive, so it's worth putting, family members or an individual under so much pressure , if the procedure is not beneficial at all?

Effects of chemotherapy

Cancer cells are known to multiply rapidly, and chemotherapy kills these fast-growing cells, but because the drugs travel throughout the whole body, they may also affect normal healthy cells that are fast growing too. The damages done to the healthy cells are what cause these side effects.

The normal, healthy cancer cells that are usually damaged are the blood-forming cells in the bone-marrow, hair follicles, cells in the mouth, digestive tract and reproductive system. Some chemotherapy drugs are known to damage cells in the heart, kidney, bladder, lungs and nervous system. There is some medicine that may or may or help these normal cells, if damage does occur.

Diagrams

This brain scan clearly demonstrates the effects on one's brain before and after chemotherapy. The dents in the second picture are the after affects, showing the resulting damages due to chemotherapy.

This graph demonstrates the life span of survival for a cancer patient. Even though chemotherapy stops the growth of cancer cells, there is a chance the cancer cells may develop again. This graph also shows that having surgery done would be a better choice for someone who has cancer to eliminate the cancer cells permanently.

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