Comparación entre dos calculadoras de riesgo en línea para la detección de cáncer de próstata versus el rendimiento de las células prostáticas circulantes en sangre para la detección de cáncer de próstata de alto riesgo en una biopsia inicial.

espanolOBJETIVO: Los nomogramas que incluyen PSA para predecir la posibilidad de una biopsia prostatica (BP) positiva para un cancer de alto riesgo son de utilidad en la clinica diaria. En este estudio de hombres con sospecha de cancer de prostata (CaP) comparamos el uso de dos nomogramas online con la deteccion de celulas prostaticas en sangre (CPCs) para predecir la posibilidad de que una BP sea positiva para CaP de alto riesgo. METODOS: Estudio prospectivo de pacientes sometidos a una BP por sospecha de CaP. Se calculo el riesgo utilizando dos nomogramas online; el SWOPPRI y el PCPT-CRC. Inmediatamente antes de la BP se tomo una muestra de sangre para detectar CPCs. Las celulas mononucleares se obtuvieron utilizando centrifugacion diferencial e identificaron utilizando doble inmunomarcacion. Las biopsias fueron clasificadas como positivas o negativas. La deteccion de CPC se clasifico como positivo o negativo. Se calcularon y compararon las areas bajo la curva del PSA, % PSA libre, SWOP-PRI, PCPT-CRC y CPCs. Se calcularon y compararon el numero de biopsias potencialmente evitadas y el numero de canceres de alto riesgo no detectados. RESULTADOS: Se analizaron 1223 pacientes, 467 tuvieron una biopsia positiva para cancer de los cuales 114 cumplieron con los criterios de observacion activa. 177 fueron Gleason 7 o mas. El AUC del PSA fue 0,559, SWOP 0,687, PCPTRC 0,716,% PSA libre 0,765 y CPCs 0,884. La deteccion de CPCs fue su- perior a los otros metodos (p CONCLUSIONES: La deteccion de CPCs fue superior a los otros modelos para predecir la presencia de un CaP de alto riesgo en la biopsia inicial; reduce po- tencialmente el numero de biopsias innecesarias y no detecta solo una pequena fraccion de los pacientes con cancer de alto riesgo. Se necesitan estudios multicentri- cos para validar los resultados de este estudio. EnglishOBJECTIVE: The limitations of total serum PSA values remains problematic; nomograms may improve the prediction of a positive prostate biopsy (PB). We compare in a prospective study of Chilean men with suspicion of prostate cancer due to an elevated total serum PSA and/or abnormal digital rectal examination, the use of two on-line nomograms with the detection of primary malignant circulating prostate cells (CPCs) to predict a positive PB for high risk prostate cancer. METHODS: Consecutive men with suspicion of prostate cancer underwent 12 core TRUS prostate biopsy. Age, total serum PSA and percent free PSA, family history, ethnic origin and prostate ultrasound results were registered. Risk assessment was performed using the online nomograms. The European Randomized Study of Screening for Prostate Cancer derived Prostate Risk Indicator (SWOP-PRI) and the North American Prostate Cancer Prevention Trail derived Prostate Risk Indicator (PCPT-CRC) were used to calculate risk of prostate cancer. Immediately before PB an 8 ml blood sample was taken to detect CPCs. Mononuclear cells were obtained by differential gel centrifugation and identified using double immunomarcation with anti-PSA and anti-P504S. Biopsies were classified as cancer/no-cancer, CPC detection test as negative/positive and the total number of cells/8ml registered. Areas under the curve (AUC) for total serum PSA, free percent, PSA, SWOP-PRI, PCPT-CRC and CPCs were calculated and compared. Diagnostic yields were calculated, including the number of possible biopsies that could be avoided and the number of clinically significant cancers that would be missed. RESULTS: 1,223 men aged > 55 years were analyzed, 467 (38.2%) had a biopsy positive for cancer of which 114/467 (24.45) complied with the criteria for active observation; 177/467 (36.8%) were Gleason 7 or higher. Discriminative power of detecting prostate cancer, showed areas under the curve of total PSA 0.559, SWOP nomogram 0.687, PCPTRC nomogram 0.716, free percent PSA 0.765 and CPC detection 0.844. CPC detection was superior to the other models (p CONCLUSIONS: CPC detection was superior to the other models in predicting the presence of clinically significant prostate cancer at initial biopsy; potentially reduces the number of unnecessary biopsy while missing few significant cancers. Being a positive/negative test it avoids defining a cutoff value which may differ between populations. Multicenter studies to validate this method are warrented.