Qian C. et al. - Photobiomodulation and Upper Limb Lymphedema Following Breast Cancer: A Systematic Review and Meta-Analysis

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In people with upper-limb lymphedema following breast cancer, photobiomodulation is associated with a reduction in the volume and circumference of the affected arm. The certainty of the evidence is considered moderate, and safety data remain insufficient.

What this study measured

Breast cancer-related lymphedema is a common complication that interferes with daily activities and negatively impacts quality of life. This systematic review with meta-analysis, conducted in accordance with PRISMA and registered on PROSPERO under number CRD420261296197, evaluated the benefits of photobiomodulation in this context. PubMed, CENTRAL, and Embase were searched through January 20, 2026, and only randomized controlled trials were included. Nine trials involving a total of 312 participants were included. The outcomes analyzed were upper limb volume, circumference, grip strength, and pain intensity. The risk of bias was assessed using the RoB 2 tool, methodological quality using the PEDro scale, and the certainty of the evidence using the GRADE method. Important note: photobiomodulation is used here as supportive care for treatment-related side effects, never as a treatment for breast cancer.

Key Findings

The four criteria point in the same direction, with low to moderate heterogeneity among studies.

Volume of the affected limb: SMD -0.78 (95% CI -1.03 to -0.54), heterogeneity I² = 22%
Penile circumference: mean difference -3.61 cm (95% CI -4.85 to -2.38), I² = 44%
Grip strength: mean difference +1.72 kg (95% CI 1.07 to 2.37), I² = 14%
Pain intensity: mean difference -0.29 (95% CI -0.52 to -0.05), I² = 0%

The reduction in pain is significant but small, and the upper limit of its range is close to zero: the observed analgesic effect remains modest.

How photobiomodulation works for this indication

The proposed mechanism is not demonstrated here and is presented as a hypothesis. Red and near-infrared light is thought to be absorbed by mitochondrial cytochrome c oxidase, which would increase ATP production and modify signaling related to reactive oxygen species. In tissue rich in interstitial fluid, this stimulation could modulate chronic inflammation, promote the formation of new lymphatic vessels, improve the contractility of lymphangions, and soften subcutaneous fibrosis. These effects would explain the reported reduction in volume and circumference.

Limits You Should Know

Nine trials and 312 participants is a small sample size for a clinical question of this magnitude. The overall risk of bias is considered low to moderate, with concerns regarding allocation concealment—an issue that may overstate the measured effects. The certainty of the evidence is mostly moderate according to GRADE: new trials could shift the estimate. Most importantly, the authors note that adverse effects are rarely reported in the included studies, so no firm conclusions regarding safety can be drawn. They explicitly call for larger and better-designed trials.

What This Means in Practice

These results position photobiomodulation as a complementary approach to standard lymph edema management, which relies on manual lymphatic drainage, compression, and exercise. It does not replace these methods. The abstract does not specify wavelengths, energy densities, or the number of sessions, and the authors note that these parameters still need to be optimized. Any decision should be made in consultation with the team managing the lymphedema.

Frequently Asked Questions

Does photobiomodulation reduce lymphedema in the arm?

In this meta-analysis of nine randomized trials involving 312 participants, it is associated with a reduction in the volume of the affected limb (SMD -0.78) and its circumference (an average reduction of -3.61 cm). This represents a reduction observed in these trials, not a complete resolution of lymphedema, which remains a chronic condition.

How many sessions does it take to see results?

The abstract of this review does not specify the number of sessions or the duration of treatment. Instead, the authors note that the parameters still need to be optimized. A trained professional can develop a protocol tailored to the specific situation.

Is photobiomodulation safe after breast cancer?

This review does not allow for such a conclusion: adverse effects were reported very rarely in the included trials, which the authors identify as a major limitation. The oncologist’s opinion remains essential before any use.

Reference

Qian C, et al. Effects of photobiomodulation therapy on upper limb lymphedema secondary to breast cancer: a systematic review and meta-analysis. Frontiers in Oncology, 2026. PMID 41948502. 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.