Types of Chemotherapy Drugs
One of the first-line treatments for cancer is chemotherapy. Following expert guidelines, doctors may prescribe it before or after cancer surgery, after a cancer recurrence, or prior to stem cell transplant, among other uses. There are many different types of chemotherapy drugs—which is a good thing because healthcare providers and patients now have more cancer treatment options than ever before.
All chemotherapy drugs target fast-growing cells. They kill cancer cells and slow the growth and spread of cancer throughout the body. The mechanisms by which different drugs cause cell death vary. According to the National Cancer Institute, chemo drugs are “grouped by how they work, their chemical structure, and their relationship to other drugs.”
Some broad classifications include:
- Alkylating agents. These drugs damage cell DNA, or deoxyribonucleic acid—the genetic code that cells need to reproduce. Oncologists use alkylating agents to treat many kinds of cancer, including leukemia, lymphoma and Hodgkin disease; sarcoma, and breast, ovarian and lung cancer. Common alkylating agents include cisplatin and carboplatin.
- Antimetabolites. These drugs get into cells and “trick” them into using the wrong material to try and reproduce. Common antimetabolite chemotherapy medications include 5-fluorouracil (also called 5-FU) and methotrexate. Doctors may use antimetabolites to treat leukemia, breast cancer, ovarian cancer and gastrointestinal cancers, including colon cancer.
- Antitumor antibiotics. These agents were first discovered in the 1960s. One common antitumor antibiotic is doxorubicin (Adriamycin). Cancer doctors may use this medicine to treat a variety of cancers, including breast cancer, bladder cancer, and blood cancers.
- Plant alkaloids. These drugs are derived from natural products like plants. Two sub-groups of plant alkaloids inhibit enzymes involved in cell division, including topoisomerase inhibitors and mitotic inhibitors. Some common plant alkaloid chemotherapy drugs include paclitaxel and vincristine. Doctors use this class of chemo drugs to treat breast, lung, ovarian, gastrointestinal, colorectal and pancreatic cancer, as well as blood cancers.
From a patient perspective, it may be more useful to classify chemotherapy medicine by route of administration. You receive most chemotherapy intravenously; a nurse injects the medication or infuses it over time into a blood vessel.
Here are other chemotherapy administration routes:
- Oral chemotherapy is administered by mouth, often in pill form. Oral chemo is much more common today than it was 20 years ago. Doctors sometimes prescribe oral chemotherapy to treat prostate, kidney and lung cancer, among other types of cancer.
- Intraperitoneal chemotherapy is delivered inside the abdominal cavity. This form of chemo can be effective in treating ovarian cancer and some gastric (stomach) cancers.
- Intrathecal chemotherapy is injected in between layers of tissue that cover the brain and spinal cord. Blood cancer specialists may use this delivery route to treat leukemia and lymphoma that has spread to this area of the body because a higher concentration of chemo reaches the tumor.
- Topical chemotherapy is rubbed onto the skin to kill skin cancer cells.
Other administration routes include direct injection into a muscle or catheter-assisted infusion directly into a tumor.
Scientists are always looking for new chemotherapy drugs and combinations of drugs. Clinical trials test the effectiveness and safety of new medications. Your healthcare provider is a good source of information about new treatments for cancer. Your doctor may even be able to refer you to a clinical trial testing novel anticancer treatments.