Why the question comes up
People reasonably associate light treatments with sunbeds, which use ultraviolet light and are a proven cause of skin cancer. Red light therapy is a different part of the spectrum. Red (around 660 nm) and near-infrared (around 850 nm) wavelengths are non-ionising: they do not carry enough energy to break chemical bonds or damage DNA. This is the fundamental reason the cancer risk from red light is not comparable to UV.
What the research shows
Photobiomodulation has been used clinically for decades and studied in thousands of papers. No study has found that it causes cancer or increases cancer risk in humans. Laboratory work has looked at whether light could stimulate existing cancer cells to grow, with mixed results in cell cultures, which is the origin of the precaution described below. In patients, the largest body of evidence comes from oncology itself, where red light is used to prevent and treat oral mucositis, a painful side effect of chemotherapy and radiotherapy. Follow-up studies of head and neck cancer patients treated this way have not shown worse cancer outcomes.
The precaution clinics follow
Because light increases cellular energy and blood flow, practitioners do not apply it directly over a known active tumour. This is a sensible precaution rather than a response to demonstrated harm, and it is why we ask about cancer history in the health screen. If you are currently being treated for cancer, we ask that you discuss red light therapy with your oncologist first, and we are happy to provide information for them.
Melanoma and skin cancer specifically
Melanoma is driven by UV damage. Red light does not produce UV and has not been linked to melanoma. Anyone with a history of skin cancer should still have unusual moles checked by a dermatologist, and treatment is not applied over a suspicious lesion.
At Omnia
Every client completes a health screen before a first NovoTHOR or THOR Laser session at our Chiswick clinic. Where there is a cancer history we tailor or defer treatment and coordinate with your medical team if you wish.