Spectrophotometric photodynamic diagnosis of prostate cancer cells excreted in voided urine using 5-aminolevulinic acid.

Abstract

To evaluate the feasibility of photodynamic diagnosis using 5-aminolevulinic acid (PDD-ALA) for detection of prostate cancer (PCa) cells in urine samples after prostate massage in patients who were suspected to have PCa. One hundred and eighty-nine patients with abnormal digital rectal examination and/or an elevated prostate-specific antigen (PSA) level who underwent initial prostate biopsy were recruited. After prostate massage, the first 60mL of voided urine was collected. For PDD-ALA, 50mL was used. The rest of collected urine was used for polymerase chain reaction (PCR) of PSA and glyceraldehyde 3-phosphate dehydrogenase (GAPDH). After incubation for 2h, the intensity was measured at 635nm under a 405-nm wavelength excitation. The results of PDD-ALA were compared with those of an initial transrectal ultrasound (TRUS)-guided prostate biopsy. Overall, 126/189 (67%) samples that showed bands of both PSA and GAPDH on PCR in urine samples were analyzed. The area under the curve, sensitivity, and specificity of PDD-ALA were 0.74, 77, and 67%, respectively. The value of PDD-ALA was significantly higher in patients with Gleason scores of 6 (p = 0.03), 7 (p = 0.005), and 8-10 (p = 0.0002) than in those with negative biopsy results. In the multivariate analysis, high PSA density, abnormal findings on TRUS, and a high value of PDD-ALA were significant markers for prediction of positive biopsy results. PDD-ALA was useful to predict positive biopsy results in patients who underwent initial prostate biopsy with suspected PCa. This PCa-detection method has potential for clinical use.