Red light therapy can be safe for some people with cancer, but it should not be used over an active or suspected tumor without approval from the oncology team. The answer depends on 3 things: the treatment area, whether cancer treatment is ongoing, and the device's wavelength and dose.
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Red Light Therapy Safety at a Glance
| Situation | General recommendation |
|---|---|
| Active cancer or a tumor near the treatment area | Do not self-treat. Ask the oncologist first, and avoid direct treatment over the tumor unless it is part of a supervised oncology protocol. |
| Chemotherapy or radiation therapy | Use red light only with approval from the cancer-care team. Some clinical protocols use photobiomodulation, but the wavelength, dose and schedule matter. |
| Oral mucositis during cancer treatment | Clinical photobiomodulation may help selected patients. MASCC/ISOO guidelines recommend defined protocols for some treatment groups. |
| Previous cancer in another body area | Red light is not known to cause cancer, but medical clearance is still sensible because devices and individual risks differ. |
| Photosensitising medication, light-sensitive disorder or eye condition | Speak with the oncologist or pharmacist before use, and follow the device's eye-protection instructions. |
| Cosmetic use at home | Do not use red light as a cancer treatment or instead of surgery, chemotherapy, radiation or prescribed medicines. |
Why Do Cancer Patients Need Medical Advice Before Using Red Light Therapy?
Cancer patients need medical advice because red light therapy affects tissue differently depending on the treatment area, wavelength, power and dose.
Red light therapy is also called photobiomodulation, low-level light therapy or low-level laser therapy. It generally uses non-ionising red or near-infrared light rather than ultraviolet radiation. The American Academy of Dermatology states that research has not found red light to cause cancer. That does not answer whether a particular dose is suitable over an existing tumor.
Photobiomodulation can affect cellular activity, blood flow, inflammation and tissue repair. Researchers have therefore studied whether certain wavelengths, doses and treatment schedules could affect tumor behavior. Human and animal research has not shown a clear increase in tumor growth with commonly used clinical parameters. Laboratory findings remain mixed, and long-term data on consumer devices are limited.
The World Association for Photobiomodulation Therapy states that photobiomodulation can be used in cancer-bearing patients in some circumstances, but it does not recommend direct treatment over a tumor site. Memorial Sloan Kettering Cancer Center also advises that its clinicians do not shine the light near tumors because the effects on tumors have not been studied sufficiently.
When May Red Light Therapy Be Used in Cancer Care?
Red light therapy is used in oncology mainly as a supportive treatment for some side effects and tissue problems. It is not an established way to kill cancer.
Oral Mucositis
Photobiomodulation may help prevent or reduce oral mucositis. This condition causes painful mouth sores during some chemotherapy, stem-cell transplant and head-and-neck radiation treatments.
The MASCC/ISOO clinical guidelines recommend defined intraoral photobiomodulation protocols for selected adults receiving:
- Hematopoietic stem-cell transplantation
- Head-and-neck radiation therapy without chemotherapy
- Head-and-neck radiation therapy combined with chemotherapy
These recommendations apply to controlled clinical protocols with specified wavelengths, energy doses and treatment schedules. They do not mean that a consumer red light mask or home panel is suitable.
Radiation-Related Tissue Problems and Wounds
Cancer centers such as Memorial Sloan Kettering use photobiomodulation for selected problems, including radiation fibrosis, treatment-related wounds, rashes and other tissue-healing issues. A trained clinician selects the treatment area and dose.
When Should Cancer Patients Avoid Self-Directed Red Light Therapy?
Do not start home red light therapy without medical clearance if you:
- Have an active tumor, suspected recurrence or an unexplained lump near the treatment area
- Are receiving chemotherapy, immunotherapy or radiation therapy
- Recently had cancer surgery
- Have skin cancer or a history of skin cancer at the treatment site
- Take a medicine that increases sensitivity to light
- Have a photosensitivity disorder or photosensitive epilepsy
- Have an open wound, infection or suspicious skin lesion in the area
- Are unsure whether the device emits red light, near-infrared light, heat or another type of radiation
FDA information for certain low-level light procedures lists active or recurrent cancer, current chemotherapy or radiation treatment, photosensitising medicines, and skin cancer or previous skin cancer at the treatment site among situations requiring caution or exclusion. Device instructions can be more restrictive than general photobiomodulation research.
How Is Red Light Therapy Different From Photodynamic Therapy?
Red light therapy and photodynamic therapy are different treatments.
Photodynamic therapy is a medical cancer treatment that uses a photosensitising drug followed by a specific light exposure. The activated drug produces chemical damage that can destroy cancer cells. Red light therapy for skin, pain or recovery usually does not use a photosensitising drug and is not an established treatment for eliminating cancer.
A red light device should not be promoted as a cure for cancer. Replacing evidence-based cancer treatment with a home device could delay necessary care.
What Are the Main Risks?
The main risks include eye injury, skin reactions, burns and unexpected effects from photosensitising medicines or skin conditions.
Most clinical photobiomodulation treatments use low energy and are generally well tolerated. Possible problems include:
- Eye injury from viewing bright LEDs or lasers without suitable protection
- Temporary warmth or tingling
- Skin redness, irritation, itching or pigmentation changes
- Burns or pain if the device is too powerful, too close or used for too long
- Unexpected reactions caused by a photosensitising medicine or skin condition
Memorial Sloan Kettering gives patients protective eyewear and uses trained staff to deliver treatment. FDA materials also identify burns, pain, itching, pigmentation changes and skin sensitivity as possible complications of some low-level light procedures.
How Should You Discuss an At-Home Device With Your Oncologist?
Take the device information to your cancer-care team before using it. Include:
- Manufacturer and model
- Wavelengths, including any red and near-infrared output
- Irradiance, measured in milliwatts per square centimetre
- Fluence, measured in joules per square centimetre
- Recommended treatment time and distance
- The exact body area you want to treat
- Every prescription medicine, supplement, cream and cancer treatment you use
Stop treatment and contact a clinician if you develop blistering, persistent pain, marked swelling, worsening redness or an unusual skin change.
Bottom Line
If your oncology team has not reviewed the device, treatment area and timing, do not start home red light therapy. Supervised photobiomodulation may have a role in managing certain cancer-treatment side effects, but a consumer device is not a substitute for cancer treatment.