Radiation Therapy vs. Chemotherapy: Key Differences, Benefits & Side Effects

Radiation Therapy vs Chemotherapy: Understanding the Difference

Radiation therapy and chemotherapy are two common treatments used to fight cancer. While both aim to destroy cancer cells, they work very differently. Radiation therapy uses high-energy rays to target cancer cells in a specific area, while chemotherapy uses drugs to treat cancer throughout the body.

The choice between radiation therapy and chemotherapy depends on the type of cancer, its stage, and the patient’s overall health. In some cases, both treatments may be used together for better results.

This article explains the differences between radiation therapy and chemotherapy, including how they work when used and what to expect from each treatment.

How Radiation Therapy Works?

Radiation therapy is a treatment which involves destroying cancer cells by using high-energy radiation beams. It usually targets a specific tumour without affecting the entire body.

External Beam Radiation: This is the most common form of radiation therapy. In external beam radiation, the tumour is destroyed by directing radiation on the body from a machine. This technique aims to kill cancer cells and usually doesn’t harm the surrounding healthy cells.
Internal Radiation (Brachytherapy): In some cases, radioactive material is placed inside or near the tumour. This method is used when a high radiation dose needs to reach the cancer cells while reducing exposure to nearby healthy cells.
When Used: Radiation therapy is often used for localised cancers, alone or before/after surgery. It helps shrink tumours before surgery or kill remaining cancer cells after surgery. It can also be used to manage symptoms in advanced cancers.

How Chemotherapy Works?

Chemotherapy involves the use of highly potent drugs to kill cancer cells. Unlike radiation therapy, which targets one specific area, chemotherapy drugs enter the bloodstream to reach cancer cells throughout the body.

Drug-Based Treatment: Chemotherapy drugs stop cancer cells from growing and dividing. Some drugs kill cancer cells directly, while others slow their growth.
Given in Cycles: Chemotherapy is usually given in cycles. You may need multiple rounds of treatments depending on how the tumour responds. It generally provides breaks in between to allow healthy cells to recover. It may be given through an IV, as a pill, or in other forms, depending on the type of cancer.
When Used: Chemotherapy is often used when cancer has spread beyond its original location. It can be used alone or with other treatments like surgery or radiation therapy.

Chemotherapy is commonly used for blood cancers, lung cancer, breast cancer, and cancers that have spread to other parts of the body.

Key Differences Between Radiation Therapy and Chemotherapy

Although both treatments aim to destroy cancer cells, they have key differences in how they work and when used.

Treatment Area: Radiation therapy focuses on a specific part of the body, while chemotherapy affects cancer cells throughout the entire body.
Method of Action: Radiation therapy destroys cancer cells by damaging their DNA, while chemotherapy stops cells from growing and dividing.
Side Effects: Radiation therapy side effects are usually limited to the treated area, such as skin irritation or swelling. Chemotherapy can cause a range of side effects in different parts of the body, such as hair loss, nausea, and a weakened immune system.
Usage: Radiation therapy is often used for localised cancers, while chemotherapy is more commonly used for cancers that have spread.

Side Effects of Radiation Therapy and Chemotherapy

Both treatments have side effects, but they vary depending on the type of treatment and the patient’s response.

Radiation Therapy Side Effects:
- Skin irritation, redness, or peeling in the treated area
- Fatigue that can last several weeks after treatment
- Swelling or discomfort in the targeted area
- Possible long-term effects, such as tissue scarring, depending on the location of treatment
Chemotherapy Side Effects:
- Nausea and vomiting, which may be managed with medication
- Hair loss is one of the most frequently reported side effects, depending on the type of chemotherapy used
- Weak immune system, making patients more vulnerable to infections
- Fatigue, which can last throughout treatment and recovery

Doctors help manage side effects with medications and lifestyle recommendations.

When is Radiation Therapy Recommended?

Radiation therapy is used in different situations, including:

As a Primary Treatment: In some cancers, radiation is the main treatment used to destroy tumours, especially when surgery is not an option.
Before or After Surgery: It may be used before surgery to reduce the size of tumours. It can similarly be used after the surgeries to kill any remaining cancer cells.
For Symptom Relief: In advanced cancers, radiation can help relieve pain and discomfort by reducing the size of tumours pressing on organs or nerves.

When is Chemotherapy Recommended?

Chemotherapy is one of the primary treatment options for cancers. It is usually allowed when cancer has spread or when other treatments alone may not be enough.

As a Main Treatment: Some cancers, leukaemia and lymphoma, require chemotherapy as the primary treatment.
Before or After Surgery: Chemotherapy can help shrink tumours before surgery or destroy remaining cancer cells after surgery.
In Combination with Other Treatments: It is sometimes combined with radiation therapy or immunotherapy to improve effectiveness.

Chemotherapy is commonly used for lung cancer, breast cancer, colon cancer, and other cancers that have spread beyond their original location.

Choosing Between Radiation Therapy and Chemotherapy

There are several factors involved in choosing between radiation therapy and chemotherapy. Some of these factors are as follows:

Type and Stage of Cancer: Localized cancers may be treated with radiation, while cancers that have spread often require chemotherapy.
Overall Health: Some patients may not tolerate chemotherapy well, while others may not be suited for radiation therapy.
Treatment Goals: If the goal is to destroy a specific tumour, radiation therapy may be used. If cancer has spread, chemotherapy is often preferred.

Doctors carefully evaluate each patient’s condition before recommending the best treatment option.

Frequently Asked Questions

Can radiation therapy and chemotherapy be used together?

Yes, in some cases, both treatments are used together. This approach is often recommended to improve effectiveness, especially for cancers that respond well to combination therapy. Radiation targets the primary tumour, while chemotherapy helps destroy cancer cells in other body parts.

Which treatment has more side effects – radiation or chemotherapy?

The side effects depend on the type of cancer, the treatment plan, and the patient’s overall health. Radiation therapy usually causes side effects, such as skin changes or fatigue, in the treated area. Chemotherapy affects the entire body and may cause nausea, hair loss, and immune system suppression.

Is radiation therapy or chemotherapy more effective?

Neither treatment is better; it depends on the cancer type and stage. Radiation therapy is effective for localised tumours, while chemotherapy is used for spreading cancers. The doctor decides the best approach based on the patient’s condition.

References

https://my.clevelandclinic.org/health/treatments/17637-radiation-therapy

https://www.nhs.uk/conditions/radiotherapy

https://my.clevelandclinic.org/health/treatments/16859-chemotherapy

https://www.cancer.gov/about-cancer/treatment/types/chemotherapy

https://www.webmd.com/cancer/cancer-chemotherapy-radiation-differences

https://www.healthline.com/health/radiation-vs-chemo

https://www.oncolink.org/frequently-asked-questions/cancer-treatments/what-is-the-difference-between-radiation-therapy-and-chemotherapy

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