Oral Cavity
1. Photodynamic Therapy in Head and Neck Cancer: Indications, Outcomes, and Future Prospects
Purpose of review: To identify and review the recent literature on clinical applications, outcome, and new developments in photodynamic therapy (PDT) for the treatment of head and neck cancer.
Recent findings: Although PDT and surgery have a similar local control and recurrence rate, the gold standard of treatment for early-stage oral cavity cancer remains local surgery with, on indication, concurrent treatment of the neck. PDT proves its value in treatment of patients with field cancerization and patients with superficial recurrence after previous surgery and/or radiation, in whom surgical salvage would entail important morbidity. PDT is also promising as an adjuvant treatment after surgery in the presence of macroscopic or microscopic involved margins, in patients where reresection or reirradiation would imply an unacceptable risk. Recent progress in the field of PDT focuses on development and clinical application of new photosensitizing agents, photochemical internalization, and photoimmunotherapy.
Summary: The value of PDT in specific well-selected head and neck cancer clinical scenarios is well established. The basic research field is rapidly evolving and experimental findings are promising, maybe eventually leading to optimized results, less side-effects, and more indications.
2. Development and Evaluation of a Low-Cost, Portable, LED-based Device for PDT Treatment of Early-Stage Oral Cancer in Resource-Limited Settings
Background: Photodynamic therapy (PDT) using δ-aminolevulinic acid (ALA) photosensitization has shown promise in clinical studies for the treatment of early-stage oral malignancies with fewer potential side effects than traditional therapies. Light delivery to oral lesions can also carried out with limited medical infrastructure suggesting the potential for implementation of PDT in global health settings.
Objectives: We sought to develop a cost-effective, battery-powered, fiber-coupled PDT system suitable for intraoral light delivery enabled by smartphone interface and embedded electronics for ease of operation.
Methods: Device performance was assessed in measurements of optical power output, spectral stability, and preclinical assessment of PDT response in ALA-photosensitized squamous carcinoma cell cultures and murine subcutaneous tumor xenografts.
Results: The system achieves target optoelectronic performance with a stable battery-powered output of approximately 180 mW from the fiber tip within the desired spectral window for PpIX activation. The device has a compact configuration, user friendly operation and flexible light delivery for the oral cavity. In cell culture, we show that the overall dose-response is consistent with established light sources and complete cell death of ALA photosensitized cells can be achieved in the irradiated zone. In vivo PDT response (reduction in tumor volume) is comparable with a commercial 635 nm laser.
Conclusions: We developed a low-cost, LED-based, fiber-coupled PDT light delivery source that has stable output on battery power and suitable form factor for deployment in rural and/or resource-limited settings. Lasers Surg. Med. 9999:1-7, 2018. © 2018 Wiley Periodicals, Inc.