Skip to main content

ACS & ASCO are Stronger Together: Cancer.Net content is now available on



Radiation Therapy for Basal and Squamous Cell Skin Cancers

Radiation therapy uses high-energy rays (such as x-rays) or particles (such as electrons) to kill cancer cells.

When is radiation therapy used?

While surgery is the most common treatment approach for basal and squamous cell skin cancers, radiation therapy may be used as the main treatment in some situations. For example, radiation might be used if a skin tumor is very large or if it’s in an area that makes it hard to remove with surgery. Radiation can also be used for people who can’t have (or don’t want) surgery for some reason.

Radiation can also be useful when combined with other treatments. For example, radiation can be used after surgery as an adjuvant (additional) treatment to kill any small areas of remaining cancer cells that may not have been visible during surgery. This can help lower the risk of cancer coming back after surgery.

Radiation may also be used to help treat skin cancer that has spread to lymph nodes or other organs.

Radiation can often be effective in treating skin tumors, but one drawback is that if a tumor comes back in the same area, it can’t usually be treated with radiation again because the side effects tend to be more severe.

How is radiation therapy given?

The 2 main ways radiation therapy can be used to treat skin cancers are external radiation therapy and brachytherapy.

External radiation therapy 

In the most common approach, the radiation is focused from outside the body onto the tumor. This is often done using a beam of low-energy x-rays (superficial radiation therapy) or electrons (electron beam radiation). These types of radiation don’t go much deeper than the skin, which helps limit the side effects to other organs and body tissues.

Getting external radiation treatment is much like getting an x-ray, but the radiation is stronger and aimed more precisely at the cancer. The procedure itself is painless. Each treatment lasts only a few minutes, although the setup time – getting you into place for treatment – takes longer.

The number of radiation treatments a person gets depends on why it’s being given. When radiation is used as the main treatment for a skin tumor (or after surgery), it’s often given 5 days a week for several weeks. Another option might be to give higher doses of radiation over fewer treatments (known as hypofractionation).


Brachytherapy is another way to deliver radiation to skin tumors, especially those on the head and neck. In this technique, a hollow applicator device is placed either on top the tumor (known as superficial brachytherapy) or directly into the tumor (known as interstitial brachytherapy). A radioactive source is then put into the applicator, usually for a short amount of time. This type of radiation travels only a short distance, so not much of it reaches nearby normal tissues. One advantage of brachytherapy is that it can typically be done in a small number of treatments, so it can be more convenient for the person getting it.

Possible side effects of radiation

Side effects of radiation are usually limited to the area being treated, and can include:

  • Skin irritation, ranging from redness to blistering and peeling
  • Changes in skin color
  • Hair loss in the area being treated
  • Damage to saliva-making glands and teeth (resulting in dry mouth and tooth decay) when treating cancers near these structures

With longer treatment, these side effects may get worse.

After many years, new skin cancers sometimes develop in areas previously treated by radiation. For this reason, radiation usually is not used to treat skin cancer in young people.

Radiation is also not recommended for people with certain inherited conditions (such as basal cell nevus syndrome or xeroderma pigmentosum), who may be at higher risk for new cancers

Radiation isn’t recommended for people with connective tissue diseases (such as lupus or scleroderma), which radiation might make worse.

More information about radiation therapy

To learn more about how radiation is used to treat cancer, see Radiation Therapy.

To learn about some of the side effects listed here and how to manage them, see Managing Cancer-related Side Effects.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.

Aasi SZ, Hong AM. Treatment of basal cell carcinomas at high risk for recurrence. UpToDate. 2023. Accessed at on August 28, 2023.

Aasi SZ, Hong AM. Treatment and prognosis of low-risk cutaneous squamous cell carcinoma. UpToDate. 2023. Accessed at on August 28, 2023.

American Society for Radiation Oncology (ASTRO). ASTRO Guideline on Definitive and Postoperative Radiation Therapy for Basal and Squamous Cell Cancers of the Skin. 2019. Accessed at on August 28, 2023.

Christensen SR, Wilson LD, Leffell DJ. Chapter 90: Cancer of the Skin. In: DeVita VT, Lawrence TS, Rosenberg SA, eds. DeVita, Hellman, and Rosenberg’s Cancer: Principles and Practice of Oncology. 11th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2019.

National Comprehensive Cancer Network (NCCN). Practice Guidelines in Oncology: Basal Cell Skin Cancer. Version 1.2023. Accessed at on August 28, 2023.

National Comprehensive Cancer Network (NCCN). Practice Guidelines in Oncology: Squamous Cell Skin Cancer. Version 2.2019. Accessed at on August 28, 2023.

Xu YG, Aylward JL, Swanson AM, et al. Chapter 67: Nonmelanoma Skin Cancers. In: Niederhuber JE, Armitage JO, Doroshow JH, Kastan MB, Tepper JE, eds. Abeloff’s Clinical Oncology. 6th ed. Philadelphia, Pa: Elsevier; 2020.

Last Revised: October 31, 2023

American Cancer Society Emails

Sign up to stay up-to-date with news, valuable information, and ways to get involved with the American Cancer Society.