Hamblin MR et al. - Photobiomodulation and Cancer: What the Data Say—A Critical Review

This brief review examines whether photobiomodulation is beneficial or harmful for people with cancer. The authors report conflicting data and conclude that the technique may have benefits and should be the subject of further research.

What This Publication Examines

The question posed is straightforward: Does applying light to the site of a tumor risk stimulating it? The authors note that this practice has been considered a contraindication. At the same time, a rapidly growing practice involves using light therapy to mitigate the side effects of cancer treatments. This brief 2018 review critically examines the available data on this topic, based on a search of PubMed and Google Scholar. One important clarification must be made when reading this text: for a person with cancer or in remission, the use of photobiomodulation must be decided and supervised by the oncology team providing care. No information page, including this one, can replace this medical decision.

Key Findings

The authors present data that do not all point in the same direction. The abstract does not provide any sample sizes, rates, or confidence intervals.

• Some articles suggest that photobiomodulation may be harmful in animal models of tumors
• Many other articles suggest the opposite, according to the authors
• Three effects are proposed in this second group of studies: light could directly damage the tumor, enhance the effectiveness of other cancer treatments, and stimulate the host’s immune system
• Two clinical trials reporting increased survival in cancer patients who received photobiomodulation are cited, with no further details provided in the abstract

The authors’ conclusion is worded cautiously: photobiomodulation may offer benefits for cancer patients and warrants further study. This uncertainty is inherent in the text and remains unresolved.

How to Interpret This Debate

The disagreement centers on the very nature of the biological effect. Photobiomodulation stimulates cellular activity, and the long-standing concern is that this stimulation may also benefit tumor cells. The three effects cited in support of an opposing interpretation are reported hypotheses, not established mechanisms, and the abstract does not specify either the models used or the doses involved. Concluding that the question remains open is more faithful to the text than concluding that there is a definitive answer.

Limits You Should Know

This is a brief, non-systematic review with no detailed inclusion criteria provided in the abstract. A significant portion of the data cited comes from animal models, and it is not clear whether these findings can be extrapolated to humans. The two clinical trials mentioned are not described in terms of sample size or protocol. Finally, according to the affiliations listed in the PubMed record, two of the three authors are affiliated with a company that markets photobiomodulation devices. Nothing in this publication provides a basis for establishing a safety profile for photobiomodulation in people with cancer.

What This Means in Practice

This review does not settle the issue and should not be interpreted as approval. It documents a scientific debate and the lack of consensus at the time of its publication. In oncology, photobiomodulation is used as a supportive care measure to alleviate certain side effects of treatments, and never as a treatment for cancer. Any use in a person with cancer—whether undergoing treatment or in remission—must be decided and supervised by their oncology team, which is familiar with the location of the disease, current treatments, and areas to avoid. Making a decision on one’s own, based solely on a publication, is not an appropriate course of action in this context.

Frequently Asked Questions

Can photobiomodulation stimulate a tumor?

This review reports that some studies using animal models support this view, while others suggest the opposite. The authors do not draw a conclusion on this point and call for further research. The uncertainty remains, and the question should be directed to the oncology team.

Can photobiomodulation be used if you've had cancer?

This publication does not provide a yes-or-no answer. The decision rests with the oncology team, which takes into account the patient’s medical history, the location of the tumor, previous treatments, and the affected areas.

Does photobiomodulation treat cancer?

No. In oncology, it is considered supportive care and is intended to address the side effects of treatment. The two studies citing increased survival are cited without details and are not sufficient to establish it as a cancer treatment.

Reference

Hamblin MR, Nelson ST, Strahan JR. Photobiomodulation and Cancer: What Is the Truth? Photomedicine and Laser Surgery, 2018. PMID 29466089. 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.