Photodynamic selectivity of 5-aminolevulinic acid to prostate cancer cells

Objective : To determine the selectivity of 5-ami-nolevulinic acid (5-ALA) as a pholosensitizer to malignant prostatic cells in men undergoing radical retropubic pros¬tatectomy. Patients and Methods : Nineteen patients with local¬ized prostate cancer were included in the study. Eighteen patients received 5-ALA and one patient did not receive it and was used as a control. The dose was 20mg / kg body weight, 15 patients received 5-ALA4 hours before radical prostatectomy, two patients received it 2 hours before prostatectomy through a Rylc tube, and one patient received 5-ALA 12 hours before the operation. The removed pros¬tates were examined for protoporphyrin IX (PpIX) fluo¬rescence macroscopically, by fluorescence microscopy and by light microscopy. Results : All carcinomas showed a clear evidence of PpIX-enrichment except in the control case. The enrich-ments were strong (++) in 15 cases and weak (+) in 3 cases. Two of those three cases were given 5-ALA two hours through a Ryle tube before excision of the prostate as well as the patient who was given 5-ALA 12 hours preoperativcly. No PpIX enrichment was observed in the stroma of the prostate gland or in the benign tissue sections in any case (0 / 19). Conclusion : Oral 5-ALA is selectively concentrated in malignant cells of the prostate. This may lead to the clinical application of photodynamic therapy for localized prostate cancer.