Precise treatment with light and oxygen 

How does photodynamic therapy work? 

A photosensitizing substance is administered to the patient in the form of a cream, gel, or intravenously. This substance accumulates primarily in pathologically altered tissues. The affected area is then irradiated with light of a strictly defined wavelength. In the presence of oxygen, reactive oxygen species are generated—highly active molecules that destroy diseased cells or microorganisms while sparing healthy tissues. 

As emphasized by Dr. Aneta Popiel-Kopaczyk from the Division of Histology and Embryology, Department of Human Morphology and Embryology at Wroclaw Medical University, it is precisely this selectivity that determines the strength of this technology. 

-Photodynamic therapy involves administering a photosensitizing substance to the patient, which accumulates in tissues that are particularly pathologically altered. After activation by light, it generates reactive oxygen species that damage infected or neoplastic tissues, the researcher explains.

The most significant changes in the perception of photodynamic therapy currently concern non-oncological fields. Particular hopes are associated with photodynamic antimicrobial chemotherapy. This method uses light to combat bacteria, fungi, and viruses, including those resistant to antibiotics. Unlike classical drugs, it does not act on a single specific microbial mechanism but induces strong oxidative stress, which leads to the destruction of pathogens.

-Photodynamic antimicrobial chemotherapy has enormous potential to become an adjunct therapy to antibiotic treatment—reducing bacterial load and biofilm and increasing treatment effectiveness,emphasizes Dr. Popiel-Kopaczyk. -This is particularly important in the context of the growing resistance of bacteria to drugs and the risks this poses for children, she adds. 

What limits the wider use of this method? 

Despite the dynamic development of technology and the growing number of studies, photodynamic therapy has not yet become a standard in many fields of medicine. This is not due to a lack of effectiveness, but rather to difficulties in implementing it in a repeatable and comparable manner across different centers. The greatest challenge remains the lack of uniform treatment standards and precise control of the therapeutic dose. Unlike classical drugs, whose doses can be clearly defined in milligrams, the effectiveness of photodynamic therapy depends on the simultaneous interaction of multiple factors. 

As emphasized by Dr. Aneta Popiel-Kopaczyk, this method requires control of three key variables: the amount of light reaching the tissues, the dose of the applied photosensitizing substance, and the availability of oxygen at the treatment site. 

-It is necessary to move from an effective method that is highly dependent on the experience of the operator to a repeatable clinical standard, the researcher notes. 
-Only then will it be possible to compare treatment outcomes, formulate strong recommendations, and implement this method more broadly, including in the treatment of children. 

An additional limitation, especially in antimicrobial applications, is the delivery of light to hard-to-reach areas, such as deep tissues or regions covered with biofilm. This requires not only advanced equipment but also well-designed protocols and appropriate training of medical personnel. 

Although photodynamic therapy is sometimes perceived as a method of the future, it is already used in clinical practice, also in Poland. It is used, among other applications, in fluorescence diagnostics and in the treatment of dental infections. This shows that the problem is not the technology itself or a lack of scientific evidence, but rather the scale of its implementation. 

The wider adoption of photodynamic therapy primarily requires the development of clear standards of practice, access to modern equipment, and systematic training of specialists. Equally important is educating physicians and patients about the mechanism of action of this method and its real clinical benefits. If these conditions are met, light-based treatment may become one of the pillars of modern medicine: effective, precise, and significantly less burdensome for patients than many currently used therapies. 

A.Hasiak