Furan and p-xylene as candidate biomarkers for prostate cancer.

BACKGROUND: Prostate cancer (PCa) is the most frequently diagnosed noncutaneous malignant tumor among males in the Western world. Prostate-specific antigen has been considered the most important biomarker for PCa detection; however, it lacks specificity, leading to the search for alternative biomarkers. Volatile organic compounds (VOCs) are released during cell metabolism and can be found in exhaled breath, urine, and other fluids. VOCs have been used in the diagnosis of lung, breast, ovarian, and colorectal cancers, among others. The objective of this study was to identify urinary VOCs that may be sensitive and specific biomarkers for PCa. METHODS: The study included 29 patients with PCa and 21 with benign prostatic hyperplasia. Urine samples were obtained from all participants before and after prostate massage. VOCs were identified by gas chromatography-mass spectrometry. IBM SPSS Statistics v.20 was used for statistical analysis. Sample normality and homogeneity of variances were studied and, according to the distribution normality, ANOVA or the Kruskal-Wallis test was applied to evaluate significant differences between groups. The Pearson test was used to establish correlations. RESULTS: Fifty-seven VOCs were identified. Samples gathered before prostate massage showed significant between-group differences in urinary levels of furan (P≤ 0.001), 2-ethylhexanol (P = 0.032), 3,5-dimethylbenzaldehyde (P = 0.027), santolin triene (P = 0.032), and 2,6-dimethyl-7-octen-2-ol (P = 0.003). Samples gathered after prostate massage showed significant differences in urinary levels of furan (P≤ 0.001), 3- methylphenol (P = 0.014), p-xylene (P = 0.002), phenol (P≤ 0.001), and 2-butanone (P = 0.001). CONCLUSIONS: Significant differences between PCa and BPH patients were found in urinary levels of certain VOCs both before and after prostate massage, supporting the proposal that VOCs may serve as PCa-specific biomarkers.

Treatment of ureteric lithiasis with retrograde ureteroscopy and holmium: YAG laser lithotripsy vs extracorporeal lithotripsy.

OBJECTIVE: To analyse the efficiency of extracorporeal shockwave lithotripsy (ESWL) vs retrograde ureteroscopy and holmium:YAG laser lithotripsy, as ESWL is successful in 67-90% of cases but endoscopic lithotripsy with pneumatic lithotrites or lasers is successful in 90-96% of distal ureteric calculi, and holmium:YAG lithotripsy is effective in proximal ureteric calculi. PATIENTS AND METHODS: From April 2006 to April 2008 we assessed 164 patients undergoing ureteric lithiasis in two homogeneous groups: group A included 83 treated with retrograde ureteroscopy and holmium:YAG endoscopic lithotripsy, and group B, 81 treated by ESWL. For laser lithotripsy we used 2071 mJ pulses at 3-6 Hz, with a mean of 1105 pulses and 2.5 kJ of total energy. ESWL was carried out using 37.5-87.5 mJ shock waves, a mean of 3650 shock waves and 187.6 J, with a radioscopy time of 1-4 min. The results were assessed after 3 weeks with plain films and ultrasonography, or urography. The efficiency of each procedure was assessed by calculating the relative risk, and results compared using the chi-square or Student's t-test. The efficiency quotient (EQ) was determined for both procedures, and the focal applied energy quotient (FAEQ) used to assess ESWL. RESULTS: The overall success rate for retrograde ureteroscopy and laser lithotripsy was 96.4% (80/83 patients), with an EQ of 0.52; a JJ catheter was placed in 67 patients. The success rate for the first ESWL session was 48%, and after repeat ESWL was 64% (52/81 patients), giving an EQ of 0.39. For successful treatments the FAEQ was 9.22, vs 6.47 for the failures (P < 0.005). There was a significant difference (P < 0.001) favouring laser lithotripsy, with an absolute benefit of 46% (95% confidence interval 33.8-57.9%), and number needed to treat of 2 (2-3), but no significant differences for lumbar ureteric calculi. CONCLUSIONS: Endoscopic lithotripsy with the holmium laser is more effective than ESWL, but for lumbar ureteric calculi ESWL is therapeutically recommended as it is less invasive.