What is the Difference Between Cytotoxic and Cytostatic Drugs

The key difference between cytotoxic and cytostatic drugs is that cytotoxic drugs destroy or kill cancer cells, while cytostatic drugs slow down or stop the growth of cancer cells without killing the cancer cells.

Chemotherapy is a treatment method for cancer that uses specific drugs. There are many different kinds of chemotherapy or chemo drugs available to treat cancer. These drugs either destroy or kill cells (cytotoxic) or prevent cancer cells from multiplying (cytostatic). These drugs are commonly called anticancer drugs. Cytotoxic and cytostatic drugs are two different types of anticancer drugs used in chemotherapy.

CONTENTS

1. Overview and Key Difference
2. What are Cytotoxic Drugs
3. What are Cytostatic Drugs
4. Similarities – Cytotoxic and Cytostatic Drugs
5. Cytotoxic vs Cytostatic Drugs in Tabular Form
6. Summary – Cytotoxic vs Cytostatic Drugs

What are Cytotoxic Drugs?

Cytotoxic drugs are drugs used to destroy or kill cancer cells. Cytotoxic means that the drug can damage the cancer cells or cause them to die. These drugs are used in chemotherapy and act on cancer cells that grow very fast. Moreover, cytotoxic drugs interrupt cells at certain places in the growth cycle as these cells are in different places in the cell division process. Cancer cells cannot be killed at once. This is the reason why a chemotherapy regimen normally includes a combination of drugs. These chemotherapy regimens also have to be repeated in order to kill all the cancer cells.

Chemotherapy cytotoxic drugs are made to kill all the cells that are fast-growing, including cancer cells as well as normal cells like hair follicles. However, new treatments such as targeted therapies and immunotherapies are not cytotoxic. These new drugs (cytostatic) work with the immune system and fight against cancerous cells. In some immunotherapies, some cytotoxic drugs can also be included. Well-known examples of cytotoxic drugs include streptozocin, doxorubicin, temozolomide, and capeccitabine.

What are Cytostatic Drugs?

Cytostatic drugs are the drugs used to prevent cancer cells from multiplying. A cytostatic agent is a substance that slows or stops the growth of cells, including cancer cells, without killing them. Cytostatic drugs are beneficial in fighting tumors because of their ability to induce cell growth arrest.

A recent study indicated that nitric oxide (NO) is able to have a cytostatic effect on the human breast cancer cell line called MDA-MB-231. The same study identified that nitric oxide stops cell growth and induces cell apoptosis after cancer cells have been exposed to nitric oxide over 48 hours. Furthermore, another recent study identified long-chain polyunsaturated fatty acids inhibit cell division and cause cell cycle arrest of malignant epithelium. In addition to that, long-chain polyunsaturated fatty acids can also induce cell death in malignant epithelial cells from various tissue organs in vitro.

What are the Similarities Between Cytotoxic and Cytostatic Drugs?

• Cytotoxic and cytostatic drugs are two different types of anticancer drugs used in chemotherapy.
• Sometimes, cytotoxic and cytostatic drugs can both be involved in immunotherapy.
• Cytostatic drugs may have cytotoxic effects as well.
• Both drugs can be used in combination with radiation.
• Both drugs play pivotal roles in increasing the survival rate of people who suffer from cancer.

What is the Difference Between Cytotoxic and Cytostatic Drugs?

Cytotoxic drugs are the drugs that destroy or kill cancer cells, while cytostatic drugs are the drugs that prevent cancer cells from multiplying. Thus, this is the key difference between cytotoxic and cytostatic drugs. Furthermore, cytotoxic drugs cause cancer cells to shrink in size. On the other hand, cytostatic drugs are not causing cancer cells to shrink in size.

The below infographic presents the differences between cytotoxic and cytostatic drugs in tabular form for side by side comparison.

Summary – Cytotoxic vs Cytostatic Drugs

Chemotherapy is a major treatment in cancer. It uses specific drugs. Cytotoxic and cytostatic drugs are two such types of anticancer drugs used in chemotherapy. They work differently against cancer cells. Cytotoxic drugs destroy or kill cancer cells. In contrast, cytostatic drugs prevent cancer cells from multiplying. They stop the growth of cancer cells without killing cells. So, this is the key difference between cytotoxic and cytostatic drugs.

Reference:

1. “Safe Handling of Cytotoxic Drugs in the Workplace.” Safe Handling of Cytotoxic Drugs in the Workplace – Health and Social Care.
2. Kischkel, Dr. Frank. “Cytostatic Drugs as a Weapon against Cancer.” TherapySelect, 3 Feb. 2020.

Image Courtesy:

1. “Temozolomide structure” By Vaccinationist – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Schematic representation of extracellular vesicle (EV) therapeutic strategies for hepatocellular carcinoma (HCC) treatment” By D’Agnano, I.; Berardi, A.C. – D’Agnano, I.; Berardi, A.C. Extracellular Vesicles, A Possible Theranostic Platform Strategy for Hepatocellular Carcinoma—An Overview. Cancers 2020, 12, 261.https://doi.org/10.3390/cancers12020261 (CC BY 4.0) via Commons Wikimedia