Researched by: Yazan Khan
Edited by: Vaidehi Jha
Chemotherapy is the usage of chemical drugs that target and kill cancer cells in the body. It is the most commonly administered treatment in cancer patients and is regarded as reliable and effective. Drugs of different mechanisms are combined during treatment to further eradicate cancer cells. There are a lot of drugs that can be used for treatment, and potential conflict of drug action is studied to determine what forms of combinational chemotherapy are viable. Most chemotherapy drugs reduce tumor growth by directly interfering with DNA processes within cancer cells.
Antimetabolites are a type of chemotherapy drug that mimic the natural nucleotides that are incorporated into DNA during replication. This drug lacks the structure to allow replication to continue, so when they are incorporated, the replication process stops. This halts the process of cell division in cancer cells, slowing growth. Common drugs of this category are Floxuridine, Hydroxyurea, and Pentostatin. Alkylating agent is another type of drug that induces mutations and causes damage within the nucleotide sequences of cancer DNA. Cancer cells, like all cells, need to express genes to function. Drugs of this category can induce damage directly into the DNA sequence, preventing necessary enzymes from binding. Without the binding of replication or transcription enzymes, cancer cells are unable to synthesize functional gene products or replicate, resulting in death. Common drugs of this category are Cisplatin, Melphalan, and Altretamine. Topoisomerase inhibitors are another drug type that stops the action of topoisomerase, a specific enzyme that is used to separate DNA strands. A lack of separation of DNA strands results in no DNA replication machinery from being able to bind, preventing the copying of DNA. Since the cell needs to duplicate its DNA prior to division, stopping this process terminates cancer cells growth. Common drugs of this category are Topetecan, Teniposide, and Irinotecan.
Chemotherapy drugs can be administered in a variety of ways. IV infusions are the most common way of treatment. It allows for venous administration, making it easier for the circulatory system to deliver to the site of the cancer growth. Drugs can also be applied as a wafer to the site of the brain tumor during surgery as an effective means to eliminate the remaining cancer cells after tumor extraction. Drug-containing pills can be orally administered, allowing for different drugs to be easily ingested at once. Skin cancers can be specifically treated with topical creams.
Chemotherapy has significant side effects and complications that introduce lifestyle and health complications for patients. Chemotherapy drugs are toxic to cancer cells as well as healthy cells. The circulation of these drugs within the brain can serve to harm neurons and impair sensory function and brain functioning. The side effect of chemotherapy that is the target for greatest research interest is the increased chance of cancer recurrence. The use of chemotherapy drugs can effectively kill many cancer cells. There will be few cells that survive due to drug resistance that can rapidly proliferate. This results in a subsequent tumor growth that is resistant to the previously administered drugs. Reproductive health can be affected, especially in older patients, resulting in infertility. Immune systems in patients can get severely compromised, leading to increased susceptibility to pathogenic infection. This increases the prevalence of infectious disease among cancer patients. Positive lifestyle changes can be implemented to improve immune response. Sustained nausea and vomiting can result in a lot of pain for patients. Steroid drugs like prednisone are administered to alleviate nausea to improve quality of life in patients.
References
How does chemo work?: Types of chemotherapy. American Cancer Society. (n.d.). Retrieved from https://www.cancer.org/treatment/treatments-and-side-effects/treatment-types/chemotherapy/how-chemotherapy-drugs-work.html
Kliegman, R. M. (2020). 521. In Nelson Textbook of Pediatrics (Vol. 21). essay, Elsevier.
Mayo Foundation for Medical Education and Research. (2022, March 22). Chemotherapy. Mayo Clinic. Retrieved from https://www.mayoclinic.org/tests-procedures/chemotherapy/about/pac-20385033#:~:text=Chemotherapy%20is%20a%20drug%20treatment,different%20chemotherapy%20drugs%20are%20available
Nurgali K, Jagoe RT and Abalo R (2018) Editorial: Adverse Effects of Cancer Chemotherapy: Anything New to Improve Tolerance and Reduce Sequelae?. Front. Pharmacol. 9:245. doi: 10.3389/fphar.2018.00245
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