Combining phototherapies with novel treatments to better combat cancer

Phototherapy is a minimally invasive cancer treatment, joining the ranks of other novel therapies such as immunotherapy and nanomedicine that offer advantages over conventional treatments like radiation and surgery. In general, phototherapies utilize light to treat cancer.

Having studied phototherapies for years, Adams et al. decided to review combinations of phototherapies with other types of cancer treatments.

Photodynamic therapy (PDT), which uses light and photosensitizers to generate reactive oxygen species, is the most used in clinical settings and has been studied the longest of the three phototherapies reviewed in this paper. Photothermal therapy (PTT) uses light to generate heat for treatment (similar to ablation), and photochemical internalization (PCI) facilitates the transport of molecules into specific areas of the body, like tumors.

“Both PTT and PCI are gaining traction in terms of their use, but PDT has a significant ‘head start’ in terms of research and development,” said author Wei R. Chen.

Each phototherapy treatment comes with its own challenges, the largest being that light can only penetrate so far into the skin. Light of most wavelengths can only penetrate a few millimeters into tissues, and while light in the near-infrared wavelength range can penetrate further, it may not have the energy to initiate treatments.

By combining phototherapies with other treatments such as immunotherapies, nanomedicines, and immune checkpoint inhibitors, clinicians can mitigate the shortcomings of phototherapies to provide more effective cancer treatments.

The future of phototherapy is personalized medicine.

“The wider range of immune therapies and a push to use machine learning and AI to customize therapies to each patient are among the most promising advancements for phototherapy,” said Chen.

Source: “Synergy between photonics and biological approaches – A review of combination therapies for cancer theranostics,” by Jacob P. Adams, Luke Pauli, Lin Wang, Trisha Valerio, Coline Furrer, Min Li, Naoko Takebe, Joanne Tuohy, and Wei R. Chen, APL Bioengineering (2025). The article can be accessed at https://doi.org/10.1063/5.0252574 .