We all know that cancer cells proliferate more rapidly than healthy cells and often "do things they shouldn't." Laser therapy functions at the cellular level, but light cannot distinguish between healthy and cancerous cells. Therefore, it is crucial to avoid laser irradiation in tumor areas to minimize stimulation of already hyperactive cell lines with adverse biological effects.

The proliferation and metastasis of cancer cells are areas of significant concern. While laser therapy may promote angiogenesis and potentially facilitate cell dissemination, the link between laser treatment and cancer cell metastasis rates has never been conclusively demonstrated. Simultaneously, laser therapy's ability to regulate microcirculation and enhance metabolism introduces uncertainty about its potential negative impact on tumor management. In conclusion, laser treatment is not recommended for tumor areas. If considering laser therapy for post-tumor resection sites, histopathological examination of surgical margins is essential to confirm complete tumor removal and suitability for laser intervention. Even with negative margin reports, residual malignant cells may persist. Before proceeding with laser therapy, it is vital to discuss these possibilities with pet owners and obtain their informed consent.

Additional considerations include the saf   ety of laser treatment at sites distant from malignancies. A preliminary study suggested improved quality of life when photobiomodulation (PBM) was used for radiation dermatitis in human breast cancer patients (Censebela et al., 2016). While PBM does induce systemic effects, current data indicate that laser therapy applied away from known malignancies appears safe for companion animals.

Palliative Care

The World Health Organization defines palliative care for patients with advanced cancer as follows: "The active total care of patients whose disease is not responsive to curative treatment. Control of pain, of other symptoms, and of psychological, social, and spiritual problems is critical. The goal of palliative care is to achieve the best quality of life for patients and their families. Many aspects of palliative care can also be applied early in the course of illness, together with anti-cancer therapies."

In cases where animal patient’s condition is severe and impending demise is certain, yet pet owners wish to enhance its quality of life, laser therapy may present a compassionate option. It can assist in managing inflammation and pain associated with certain cancers, allowing the animal to spend its final days more comfortably.

New Insights into Laser Therapy Applications

As more experimental research papers are published, the evaluation of the feasibility of laser therapy for malignant tumors may evolve. A systematic literature review in 2012 presented existing data on the potential applications of laser therapy in the treatment of solid tumors (Sattana-Blank et al., 2012a). This review suggests that laser therapy may assist in restoring homeostasis and homeostatic movement in cancer patients. It indicates that by reconstructing physiological rhythms and inducing physiological repair effects for disease reversal in cancer and other complex diseases, laser therapy may significantly improve quality of life with minimal or no side effects.

Based on the available evidence, they argue that PBM (Photobiomodulation) can enhance standards of care and improve quality of life for cancer patients and those with other complex diseases. They note that over the past few years, there has been a new understanding of PBM's role in cancer treatment (Karu, 2010; Lanzafame, 2011; Sattana-Blank et al., 2012b)

References

[1] Veterinary Laser Therapy in Small Animal Practice - Bryan J. Stephens

[2] Laser Therapy in Veterinary Medicine Photobiomodulation - Ronald J. Riegel and John C. Godbold, Jr.