Clinical uses of 5-aminolaevulinic acid in photodynamic treatment and photodetection of cancer: A review

CASAS, ADRIANA

CANCER LETTERS

ELSEVIER IRELAND LTD

Año: 2020

0304-3835

(PDT) research for cancer treatment. 5-aminolaevulinic acid (ALA) is the prodrug of the photosensitiser ProtoporphyrinIX (PpIX). After ALA administration, cells generate PpIX through the haem biosynthetic pathway. Althoughthe exact reasons for ALA/PpIX selectivity are unknown, it is believed that due to the special regulationof haem enzymes, PpIX is accumulated in the tumours.Both ALA and its derivative ALA Methyl ester, are mainlyused in dermatology. Besides, ALA-PDT has been employed for palliative and even curative treatment of endoscopicallyaccessible tumours. Lung, oesophagus, gastric and bladder carcinomas, and also oral premalignant lesions,gynaecological intraepithelial neoplasias and Barrett's oesophagus are the conditions mostly treated withALA-PDT. However, due to the limited penetration of ALA and light, non-dermatologic uses of ALA-PDT havenot moved beyond phase I clinical trials.On the other hand, ALA-induced PpIX fluorescence is employed for thePhotodynamic Diagnosis (PDD) or assistance in cytoreductive surgery (Fluorescence-guided Resection, FGR).ALAhas been approved for the FGR of high-grade gliomas and ALA Hexyl ester, for fluorescence cystoscopy in thediagnosis of bladder cancer. ALA-FGR is currently applied in brain, bladder, lung, colon cancers and ALA-PDDfor oral premalignancies, gynaecological intraepithelial lesions and peritoneal metastases, among others. Besides,PDT can be applied concomitantly in the same diagnostic procedure.This review aimed to analyse the state of theart of clinical uses of ALA in the areas of treatment and detection in the non-dermatologic oncology