Clinical research of photodynamic therapy with 5-ALA for cervical intraepithelial neoplasms: from preliminary studies to current developments

Non-surgical therapies are essential for reducing the progression rate of human papillomavirus-associated cervical intraepithelial neoplasia (CIN) from low-grade (CIN 1) to high-grade CIN (CIN 2/3) and subsequently to cervical cancer with minimal adverse reactions and complications in women, such as haemorrhaging, cervical stenosis, spontaneous abortion, and preterm birth.Photodynamic therapy (PDT) has garnered considerable attention as a non-invasive approach to CIN treatment in recent years. PDT works by applying photoactive compounds, known as photosensitizers, that accumulate in target cells. Subsequent exposure of these cells to light of a specific wavelength (photoactivation) occurs. This paper aims to review the clinical development of clinical research on the effectiveness of PDT with a 5-Aminolevulinic acid (5-ALA) photosensitiser for treating CIN 1-3 from the early preliminary studies to recent reports.Early PDT studies using lower concentrations of 5-ALA showed poor effectiveness, but recent research with a 20% concentration of 5-ALA demonstrated better outcomes. Larger studies, preferably conducted across multiple centres, are needed to establish the optimal number of PDT sessions required to eliminate HPV.