Teng C. et al. - Photobiomodulation for chemotherapy-induced peripheral neuropathy in cancer survivors

In this phase II randomized trial involving 44 cancer survivors, 48% of participants in the photobiomodulation group and 53% of those in the placebo group showed a response to neuropathy symptoms at 6 weeks. The trial was not designed to compare the two arms, and the placebo performed as well as the light treatment at that time point.

What this study measured

Chemotherapy-induced neuropathy often persists after treatment has ended, and there is still no established treatment for it. The authors conducted a phase II, noncomparative, placebo-controlled, single-blind randomized trial involving 44 cancer survivors who were symptomatic at least three months after receiving neurotoxic chemotherapy.

Participants were randomized in a 2:1 ratio to laser photobiomodulation or placebo, with two sessions per week for a total of twelve sessions. Assessments were conducted at baseline, at 6 weeks, and at 12 weeks and included questionnaires on neuropathy, quality of life, and function, as well as a neurological examination. The primary endpoint was the proportion of responders: resolution of symptoms or a reduction reaching the minimum clinically important difference. Photobiomodulation is used here as supportive care, never as a treatment for cancer.

Key Findings

Both groups showed improvement, with no advantage for the laser group at the end of the procedure.

• Response at 6 weeks: 48% in the photobiomodulation group, 53% in the placebo group
• Response at 12 weeks: 45% in the photobiomodulation group, 33% in the placebo group
• Hypothèse nulle d’un taux de réponse de 5 % dans le bras laser rejetée à 6 et 12 semaines, p < 0,001
• Reported symptoms: improvement in both groups compared with baseline
• At 12 weeks: improvement sustained with photobiomodulation; return to baseline values with the placebo
• Neurological signs, quality of life, and function: stable in both groups
• Mild adverse effects in both arms

The summary does not report any confidence intervals, comparisons between treatment arms, wavelengths, or doses.

How Photobiomodulation Affects the Peripheral Nerves

The proposed mechanisms remain hypothetical. Red or near-infrared light is thought to be absorbed by mitochondrial cytochrome c oxidase, which would increase ATP production. A reduction in oxidative stress and modulation of inflammatory pathways are also suggested, along with the hypothesis that these conditions may be more conducive to axonal regeneration. This study did not measure any of these parameters.

Limits You Should Know

Le point le plus important est le plan non comparatif : l’essai testait si le taux de réponse sous laser dépassait 5 %, un seuil très bas, et non une supériorité sur le placebo. Le résultat annoncé (p < 0,001) porte uniquement sur ce seuil.

The negative result must be stated clearly: at 6 weeks, the placebo group had a higher response rate (53% versus 48%). Neurological signs, quality of life, and function remained stable in both groups: no objective benefit was documented. The sample size is small; the 2:1 ratio further reduces the placebo arm; and the blinding was simple. The authors themselves conclude that a larger trial is needed.

What This Means in Practice

This trial does not provide a basis for recommending photobiomodulation for this indication. At best, it suggests that the benefit might persist after the end of the treatment sessions in the active arm, but this remains to be confirmed. Photobiomodulation does not treat cancer and is not a substitute for any prescribed treatment: any use of this therapy should be discussed with the oncology team.

Frequently Asked Questions

Is photobiomodulation more effective than a placebo in treating chemotherapy-induced neuropathy?

In this trial, at 6 weeks: the placebo group had a 53% response rate, compared with 48% for photobiomodulation. At 12 weeks, the trend reversed (45% versus 33%), but no superiority test was reported. The question remains open.

How many sessions were included in the protocol for this trial?

Two sessions per week for up to twelve sessions in total, spread over six weeks, with an evaluation six weeks after completion. The abstract does not specify the wavelength, dose, or duration of the sessions.

Is photobiomodulation safe after cancer?

Mild adverse effects were reported in both treatment groups, including the placebo group. This trial involved survivors who had completed chemotherapy at least three months prior, and does not address use during active treatment. Consultation with an oncologist is essential.

Reference

Teng C, Egger S, Blinman PL, Vardy JL. Evaluating laser photobiomodulation for chemotherapy-induced peripheral neuropathy: a randomized phase II trial. Supportive Care in Cancer, 2022. PMID 36526802. View the study on PubMed

This summary is provided for informational purposes only and does not constitute medical advice. Photobiomodulation is not a substitute for prescribed treatment. Consult a healthcare professional.