Chemotherapeutic agents are a type of cancer treatment utilizing powerful chemicals to eliminate fast-growing cells within the body. This treatment aims to destroy cancer cells and prevent them from spreading. Chemotherapy is a systemic treatment, meaning it travels through the bloodstream to reach cancer cells throughout the body, including those that may have spread from the original tumor.
How Chemotherapy Works
Chemotherapy drugs target and destroy rapidly dividing cells, a characteristic common to cancer cells. These drugs interfere with the cell cycle, the process by which cells grow, copy their genetic material (DNA), and divide to form new cells. Different types of chemotherapy agents may disrupt various phases of this cycle, making them effective against different types of cancer cells.
Some drugs damage the DNA within cancer cells, preventing them from replicating and leading to programmed cell death, known as apoptosis. Other agents interfere with the formation of structures necessary for cell division, such as mitotic spindles.
While chemotherapy is designed to primarily affect fast-growing cancer cells, it can also impact healthy, rapidly dividing cells in the body, which explains why certain side effects occur. Normal cells, such as those in hair follicles or the digestive tract, also divide quickly, making them susceptible to the drugs’ effects.
Categories of Chemotherapeutic Drugs
Chemotherapeutic drugs are categorized based on their chemical structure and how they act on cancer cells.
Alkylating agents, for example, work by altering the DNA of cancer cells, preventing them from copying their genetic material and ultimately leading to cell death. Examples include cyclophosphamide, cisplatin, and carboplatin.
Antimetabolites mimic natural substances required for DNA synthesis, tricking cancer cells into incorporating these false building blocks into their DNA, which then disrupts the cell’s ability to grow and divide. Fluorouracil and gemcitabine are common antimetabolites.
Antitumor antibiotics, which are different from antibiotics used for infections, interfere with DNA inside cancer cells to prevent their growth and division.
Plant alkaloids, also known as mitotic inhibitors, block the process of cell division (mitosis), preventing cancer cells from multiplying. Paclitaxel and vinblastine are examples of these drugs.
Topoisomerase inhibitors target enzymes called topoisomerases, which are necessary for DNA replication and repair in cancer cells, thereby preventing cell division.
Administering Chemotherapy and Managing Effects
Chemotherapy can be administered in several ways, including intravenous (IV) infusion, oral pills, injections, and topical creams. IV infusion, a common method, delivers drugs directly into a vein. Other methods include injections into specific body areas or oral pills taken at home.
Common side effects include:
Fatigue, often due to the body’s effort or anemia.
Nausea and vomiting.
Hair loss, typically within the first few weeks.
Mouth sores and sore throat.
Changes in taste and smell.
Strategies to manage these effects include:
Anti-nausea medications.
Eating small, frequent meals.
Being gentle with hair and scalp.
Consulting with the care team for pain control.
Chemotherapy’s Role in Cancer Care
Chemotherapy plays a varied role within comprehensive cancer treatment plans. Its purposes include reducing the overall number of cancer cells, shrinking tumor size, and lessening cancer symptoms. It can also be used to decrease the likelihood of cancer spreading to other parts of the body.
This treatment is often integrated with other modalities. For example, chemotherapy might be given before surgery to shrink a tumor, a process known as neoadjuvant therapy, which can improve the chances of complete surgical removal. Conversely, it may be administered after surgery or radiation therapy, called adjuvant therapy, to destroy any remaining cancer cells. Chemotherapy is frequently combined with radiation therapy, targeted therapy, or immunotherapy, as using multiple approaches can improve treatment effectiveness and help overcome drug resistance.