Photodynamic therapy: Basics and new directions for clinical applications.

Photodynamic therapy (PDT) remains a developing modality in cancer treatment. It is a minimally invasive approach that employs a photosensitizing drug, activated by light, to induce localized cytotoxic effects. Initially introduced in oncology, PDT has proven effective for cancers such as skin malignancies and head and neck tumors, while sparing surrounding healthy tissue. Beyond oncology, its use has expanded to dermatology, ophthalmology and dentistry, and it shows promise in the management of chronic inflammatory conditions, pediatric nephrology and emerging applications in cardiovascular and neurodegenerative diseases. Despite persistent challenges such as limited light penetration, advances in photosensitizers and integration with technologies including immunotherapy and polymeric nanocarriers underscore PDT's potential as a versatile tool in precision medicine. Recent studies suggest that PDT can also modulate the tumor microenvironment (TME) and stimulate anti-tumor immune responses, thereby enhancing its therapeutic impact. Consequently, it is increasingly being investigated in combination with other treatment modalities to overcome resistance and improve patient outcomes.