Chemotherapy is a major weapon in the battle against cancer. The types of chemotherapy vary depending on patient needs, but they all share the fact that they travel through the bloodstream and go after cancer cells in every part of the body.
6 Primary Types of Chemotherapy
The type of chemotherapy chosen for a particular person depends on various factors. These include the type of cancer, its stage, the person’s overall health and, to some degree, the person’s preference. With combination therapy, more than one chemotherapy drug may be used at the same time. Every person receives a customized chemotherapy plan based on their genetic profile.
While chemo is just one element of cancer treatment, there are situations in which chemo alone is considered curative. Even if chemo cannot cure the disease, it can boost a person’s lifespan and improve their quality of life.
The six primary types of chemotherapy include:
- Alkylating Agents
These are the first chemotherapy drugs used and remain among the most common today. The agents work by preventing cancer cells from reproducing, destroying cells in all cell cycle phases. Some of the best-known alkylating agents include Chlorambucil, Cisplatin and Cyclophosphamide. They are targeted primarily at slow-growing cancers. Alkylating agents are less effective on cells experiencing rapid growth.
These drugs — such as Carmustine and Lomustine — work in a manner similar to alkylating agents. However, nitrosoureas can penetrate the blood/brain barrier which is not true of most chemotherapy drugs.
These drugs — which include Fluorauracil and Methotrexate — interfere with the cells DNA and RNA when cells are dividing. Think of antimetabolites as tricking the cells into thinking they are nutrients needed for growth. These cells eventually starve and die.
- Antitumor Antibiotics
Cell cycle is nonspecific, these chemotherapeutic agents bind with DNA to prevent RNA synthesis. By inhibiting this synthesis (which creates proteins), cancer cells cannot reproduce. Examples include bleomycin, Doxorubicin and mitoxantrone. The drugs are not the same as antibiotics used to treat infections.
- Plant Alkaloids
Made from natural plant products, drugs such as Vincristine and Paclitaxel stop the cells’ ability to divide in two. They also repair cell damage. The category of plant alkaloids includes topoisomerase inhibitors — medications that block the topoisomerase enzyme. These drugs target specific phases of the cell cycle. Mitotic inhibitors inhibit cell division ( also called mitosis). It is through mitosis that cancer cells metastasize (spread) throughout the body.
- Hormonal Agents
This therapy adds, blocks or takes out specific hormones so they cannot attach to cancer cells. Tamoxifen — used to combat breast cancer — is among the most frequently prescribed hormonal agents.
At What Stage of Cancer Is Chemotherapy Used?
Chemotherapy is used at any cancer stage . Not all people diagnosed with cancer require chemo. Cancer stages are numbered from I to IV. Many people in Stage I are treated with surgery and radiation alone, but doctors may recommend chemo if the cancer is aggressive.
Chemotherapy Before Surgery
Most people receive chemotherapy after surgery to remove their tumors. This is known as adjuvant chemotherapy. However, using neoadjuvant therapy, oncologists may decide to administer chemo prior to surgery or radiation to shrink the tumors.
How Chemotherapy Is Delivered
Patients receive chemo in many ways which is based on their particular diagnosis. Chemo delivery systems include:
- Oral chemotherapy: Delivered via mouth, usually in the form of pills, capsules or liquids.
- Intravenously: IV chemo is injected into a vein. This is done on a regular schedule at a treatment center or a port may be installed to receive continuous infusion.
- Intramuscular: Injected deep into muscle tissue that allows the treatment to be absorbed quickly.
- Intraperitoneal: Injected into the peritoneal cavity. This area contains the intestines, liver and stomach. This method is used primarily for cancers that have spread to the peritoneum including ovarian cancer.
- Intrapleural: Chemo is delivered into the chest cavity into the pleura (the lining covering the lungs). This method is used for treating lung cancer and breast cancer that has spread to the lungs.
- Topical: A cream rubbed into the skin.
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Jane Meggitt’s work has appeared in dozens of publications including USA Today, Zack’s, Financial Advisor, nj.com, The Houston Chronicle and The Nest. She is a graduate of New York University.
University of Iowa Hospitals and Clinics – Types of chemotherapy
National Cancer Institute – Types of Chemotherapy Drugs
Osmosis – Topoisomerase inhibitors
Cleveland Clinic – Chemotherapy: What Is It, Types & Causes
Cancer.net – What is Chemotherapy?