How do you navigate the information on red light therapy when cancer is an issue? Let's cut the confusion and answer the most important safety questions using current scientific understanding.

Red Light Therapy is contraindicated when used directly over a known active tumor due to the theoretical risk of stimulating cancer cells or promoting blood vessel growth (angiogenesis), which could feed the tumour. RLT is not ionizing like X-rays and UV light, but it does not cause cancer. If you have cancer or a history thereof, consult your oncologist prior to using RLT.

 

RLT is fundamentally different from UV radiation, which causes cancer.

RLT is a complex topic because it works by stimulating cell activity. This is great for treating wounds and reducing inflammation. But when malignant cells come into play, it raises the question: Could we accidentally stimulate the wrong cells in the process? This is a legitimate concern, which requires careful consideration. It is important to separate what we know from speculative claims and highlight the importance of expert guidance. Safety and transparency are of paramount importance to manufacturers who provide RLT solutions worldwide.

Can red light therapy cause cancer?

First, let's tackle the biggest concern: Can RLT devices cause cancer? The known dangers of UV radiation from the sun and tanning beds are often the cause of cancer-related concerns.

There is no evidence that Red Light Therapy, which uses therapeutic red and near infrared wavelengths, causes cancer. RLT uses wavelengths which are non-ionizing and do not cause DNA damage like UV radiation. The primary mechanism is to enhance cellular function and not induce mutations.

Imagine UV light as a powerful bullet capable of directly breaking DNA strands and causing mutations which could lead to cancer. Red and NIR are gentle energy packets which are absorbed into specific areas of the mitochondria to increase energy production.

Why RLT is not considered carcinogenic

Non-Ionizing Light: NIR (700-1100nm), and red (600-700nm), fall under the non-ionizing spectrum. They don't have the energy per photon needed to knock electrons from atoms and molecules. This is what makes UV, X, and Gamma Rays harmful to DNA.

RLT's mechanism of action is thought to be the cytochrome-c oxidase in mitochondria. This leads to an increase in cellular energy, modulation of ROS and activation signaling pathways that are related to healing and inflammation.

Lack of epidemiological link: Decades worth of research and clinical usage of PBM/RLT to treat various conditions has not led to any evidence that its use increases cancer rates.

Although excessive doses and inappropriate energy modality use warrant caution, therapeutic RLT's fundamental mechanism does not align itself with the known causes of cancer.

Can red light therapy make existing cancer worse?

This is a more complex and significant concern. Could RLT increase the activity of cancerous cells, accelerating their growth and spread?

It is important to note that this is a theoretically valid risk. This is the main reason RLT is contraindicated over active tumors, without medical supervision. RLT may inadvertently promote tumor growth or spreading by increasing cellular energy (angiogenesis) and possibly local blood flow. The evidence is mixed and largely based on lab studies. This calls for extreme caution.

You can think of it as a wound that you want to heal quickly (good cells), versus feeding cancer cells in the same place. You don't need to stimulate the wrong side.

Explore the Theoretical Risks

In vitro studies (lab dishes) have shown that PBM stimulates the proliferation of cancer cells. The results vary widely, depending on cell type, light parameters, (wavelength dose intensity) and study conditions. In vitro effects don't always translate into complex in vivo environments (living organisms).

RLT promotes angiogenesis, which can be beneficial to wound healing. Angiogenesis is also important for tumors to obtain nutrients and oxygen. It is not a good idea to stimulate blood vessel growth around a tumor.

RLT has a pro-survival effect on cells. Although apoptosis (programmed cell death) is beneficial for healthy tissues, it would be counterproductive to reduce apoptosis in cancer cells.

The most important thing to know is that these concerns are mostly based on lab studies using isolated cells or animal model. There are no high-quality data from humans on the application of RLT directly to tumours (for obvious reasons). The medical community is right to be cautious.

Potential Effect of RLT	Benefit in Healthy Tissue	Theoretical Risk with Cancer Cells
Increased ATP/Energy	Faster Healing, Better Function	Potential for Faster Growth
Increased Angiogenesis	Improved Circulation, Healing	Potential Tumor Blood Supply
Modulated Inflammation	Reduced Pain & Swelling	Complex effects on tumor microenv.
Pro-Survival Signals	Tissue Protection	Potential Cancer Cell Survival

 

 

Bottom line: Do not treat directly over or near an existing tumor, unless you're part of a clinical trial or are under the guidance of your oncologist.

Can RLT be used safely by cancer patients for other issues?

Does this mean that anyone who has a history or is currently receiving treatment for cancer should completely avoid RLT? Not necessarily.

Under strict medical supervision, RLT/PBM are being studied and used to manage certain side effects from cancer treatments such as oral mucositis, (painful sores in the mouth caused by chemo/radiation). It is important to note that RLT is only applied to non-tumor tissues to reduce symptoms and promote healing, not to cancer.

It is important to distinguish between using RLT for side effects of treatment and using it directly on cancer.

Supportive care examples:

Oral Mucositis: This is the most common application. The application of RLT inside the mouth reduces the severity and length of OM due to head/neck radiation or chemotherapy, and improves the patient's quality of life. Many oncology centers now incorporate PBM protocols for OM prevention/treatment.

Radiation Dermatitis - Some studies have explored the use of RLT to reduce skin damage from radiation therapy.

PBM may help relieve nerve pain caused by certain chemotherapy drugs. Research is ongoing.

Considerations to Supportive Care

Medical supervision is non-negotiable. These applications MUST be performed under the guidance of an oncology team. This is often integrated into cancer treatment centers' protocols.

The light is targeted at the area affected by side effects (e.g. the oral lining or skin), and not the location of the tumor.

Risk vs. Benefit Assessment: An oncologist will weigh the theoretical risks against the benefit of symptom relief based on the cancer type, stage and location as well as the overall treatment plan.

If you have cancer elsewhere, it is important to discuss this with your oncologist. Systemic effects of cancer are not well understood.

Conclusion 

Red Light Therapy's relationship with cancer is complex. Although RLT (Red/NIR Light) does not cause Cancer like UV radiation, it is contraindicated to apply it directly over an actively growing tumor due to the risk of stimulating unwanted development. RLT is a useful tool for treating debilitating cancer side effects like oral mucositis, but only under medical supervision. Consult your oncologist if you are currently undergoing cancer treatment or have a cancer history.