What is the Difference Between Chemotherapy and Radiotherapy

The main difference between chemotherapy and radiotherapy is that chemotherapy uses special drugs to shrink or kill cancer cells while radiotherapy uses high-energy beams such as X-rays or protons to kill cancer cells.

Chemotherapy and radiotherapy are two types of treatments used in cancer, which is an uncontrolled growth and spread of cells to surrounding tissues. The main goals of both treatments are to cure or get rid of cancer cells, control or shrink or slow cancer cells, and shrink tumors to reduce pain.  

Key Areas Covered

1. What is Chemotherapy
   • Definition, Characteristics, Importance
2. What is Radiotherapy
   • Definition, Characteristics, Importance
3. Similarities Between Chemotherapy and Radiotherapy
   • Outline of Common Features
4. Difference Between Chemotherapy and Radiotherapy
   • Comparison of Key Differences

Key Terms

Cancer, Chemotherapy, Radiotherapy

What is Chemotherapy

Chemotherapy is the treatment of cancer using chemicals. Therefore, medication is given to kill cancer cells. Chemotherapy drugs circulate in the bloodstream. They kill or shrink cancer cells anywhere in the body, not just at the site where the first (primary) cancerous tumor starts. Because these drugs pass through your whole system, they’re called “systemic.” The delivery of chemotherapy can be in three methods: IV (through a needle or a tube directly into a blood vessel), oral (from a pill or capsule that you swallow), and injection (through a needle into the skin or muscle).

Figure 1: Chemotherapy

Chemotherapy is designed to kill the rapidly dividing cells of the body. However, in addition to cancer cells, it also rapidly divides hair follicles, nails, mouth, digestive tract, and bone marrow cells. Chemotherapy unintentionally destroys both cell types.

What is Radiotherapy

Radiotherapy is the treatment of cancer by high-energy beams such as X-rays or protons. Radiation treatments use invisible bursts of energy instead of drugs. In addition, it is usually a “local” treatment that aims energy beams just at the area where cancer cells grow. In addition, radiation treatment can use three methods: external radiation (a machine outside the body shoots invisible high-energy beams into the tumor), internal radiation, or “brachytherapy” (a radioactive object is placed inside the body close to the tumor), and systemic radiation (less common treatment that uses radiation as a systemic treatment that works throughout the body).

Figure 2: Radiation Therapy

However, the type of radiation therapy depends on several factors: the type of cancer, the size of the tumor, the tumor’s location in the body, how close the tumor is to normal tissues that are sensitive to radiation, general health and medical history of the patient, other types of cancer treatment, age, and other medical conditions.

Similarities Between Chemotherapy and Radiotherapy

• Chemotherapy and radiotherapy are two types of cancer treatments.
• Their function is to cure and control cancer.
• However, there are side effects in both treatments, including tiredness, hair loss, nausea and vomiting, diarrhea, skin changes, and anemia.

Difference Between Chemotherapy and Radiotherapy

Definition

Chemotherapy refers to the treatment of disease by the use of chemical substances, especially the treatment of cancer by cytotoxic and other drugs, while radiotherapy refers to the treatment of disease, especially cancer, using X-rays or similar forms of radiation.

Agents

Usually, chemotherapy uses drugs to treat while radiotherapy uses high-energy beams such as X-rays to treat.

Type of Treatment

Chemotherapy is a systemic treatment while radiotherapy is a local treatment.

Treatment Methods

Chemotherapy treatment methods include oral, intravenous, and injections while radiotherapy treatment methods include external, internal, and systemic radiation.

Conclusion

In brief, chemotherapy and radiotherapy are two methods of cancer treatment. Usually, chemotherapy involves the use of drugs to treat cancer while radiotherapy involves the use of high-energy beams. In general, chemotherapy treatments are systemic while radiotherapy treatments are local.  Thus, the main difference between chemotherapy and radiotherapy is the method of treatment. However, it’s important to know that the type of treatment depends on the development of the disease.

References:

1. Mayo Foundation for Medical Education and Research. (2022, March 22). Chemotherapy. Mayo Clinic. Retrieved August 31, 2022
2. Radiation therapy for cancer. National Cancer Institute. (n.d.). Retrieved August 31, 2022

Image Courtesy:

1. “Chemotherapy with acral cooling” By Jenny Mealing – Own Work (CC BY 2.0) via Commons Wikimedia
2. “Radiation therapy” By Dina Wakulchik – Own Work (CC BY 2.0) via Commons Wikimedia