RESUMEN
PURPOSE: We tested the hypothesis that a single exogenous androgen injection in men with low prostate specific antigen would provoke a differential prostate specific antigen response that would correlate with the presence and volume of cancer at biopsy. MATERIALS AND METHODS: Following institutional review board approval 40 men with prostate specific antigen between 2.5 and 4.0 ng/ml were given 1 intramuscular injection of 400 mg testosterone cypionate at the start of the study. Prostate specific antigen and early morning serum testosterone were measured at baseline, 48 hours, and weeks 1, 2 and 4. All men underwent 12-core transrectal ultrasound guided biopsy at week 4. RESULTS: Of the 40 men 18 (45%) were diagnosed with prostate cancer. The mean change in prostate specific antigen from baseline to 4 weeks was 3.1 to 3.4 ng/ml (9.7%) in men found to have benign findings on biopsy compared to a mean increase of 2.9 to 3.8 ng/ml (29%) in those with prostate cancer (p = 0.006). The change in prostate specific antigen following androgen stimulation was significantly associated with the percent of tissue involved with cancer and it was an independent predictor of cancer diagnosis on univariate and multivariate analysis. CONCLUSIONS: An increase in prostate specific antigen following androgen stimulation in men with prostate specific antigen between 2.5 and 4.0 ng/ml was highly predictive of the subsequent diagnosis of prostate cancer and it correlated with disease volume. If these findings are corroborated, prostate specific antigen provocation may become an important strategy to identify men at risk for harboring prostate cancer and minimize the number undergoing unnecessary biopsies.
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Andrógenos/farmacología , Antígeno Prostático Específico/sangre , Antígeno Prostático Específico/efectos de los fármacos , Neoplasias de la Próstata/sangre , Neoplasias de la Próstata/diagnóstico , Testosterona/análogos & derivados , Anciano , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Testosterona/farmacologíaRESUMEN
BACKGROUND: The current study was conducted to develop a prognostic model of event-free survival (EFS) in men with androgen-independent prostate carcinoma (AIPC). METHODS: Data from 160 patients diagnosed with AIPC between 1989-2002 were reviewed. No patient had received cytotoxic chemotherapy. A univariate Cox proportional hazards model identified significant predictors of EFS. Recursive partitioning analysis divided these significant variables into prognostic risk groups. The final prognostic model was tested with a Cox proportional hazards model. RESULTS: The final prognostic risk model included the presence of metastatic disease at the time of androgen-independent disease progression (P = 0.040), time to prostate-specific antigen (PSA) recurrence (P = 0.043), and PSA doubling time (P < 0.01). Three highly independent risk groups were identified. The observed median EFSs were 6.1 months (95% confidence interval [95= CI], 3.4-8.8 months), 33.6 months (95= CI, 25.3-41.9 months), and 96.1 months (95= CI, 57.9-134.3 months) for the low-risk, intermediate-risk, and high-risk groups, respectively. Each risk group was found to be independently predictive of EFS (P < 0.01). Patients who died of prostate carcinoma experienced significantly more clinical events than those who died of other causes (P < 0.01). CONCLUSIONS: The prognostic model in the current study stratified patients into three highly significant and independent risk groups for EFS. A detailed PSA history and knowledge of metastatic disease are sufficient to risk-stratify patients with AIPC. One very unique aspect of this model was that it was developed from a patient cohort that never received chemotherapy.
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Modelos Biológicos , Neoplasias Hormono-Dependientes/mortalidad , Neoplasias de la Próstata/mortalidad , Anciano , Anciano de 80 o más Años , Andrógenos/uso terapéutico , Estudios de Cohortes , Progresión de la Enfermedad , Supervivencia sin Enfermedad , Humanos , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Neoplasias Hormono-Dependientes/diagnóstico , Neoplasias Hormono-Dependientes/terapia , Pronóstico , Antígeno Prostático Específico/metabolismo , Prostatectomía , Neoplasias de la Próstata/diagnóstico , Neoplasias de la Próstata/terapia , Estudios Retrospectivos , Factores de Riesgo , Tasa de Supervivencia , Resultado del TratamientoRESUMEN
PURPOSE: Training on a virtual reality (VR) simulator has been shown to improve the performance of VR endoscopic tasks by novice endoscopists. However, to our knowledge the translation of VR skills into clinical endoscopic proficiency has not been demonstrated. We established criterion validity for a VR ureteroscopy simulator by evaluating VR trained subjects in a cadaver model. MATERIALS AND METHODS: A total of 32 participants, including 16 medical students and 16 urology residents, were evaluated at baseline on a VR ureteroscopy simulator (Uromentor, Simbionix, Lod, Israel), performing simple diagnostic ureteroscopy. The students then underwent 5 hours of supervised training on the simulator. Two weeks later all participants were reevaluated (VR2) on the simulator when repeating the initial task. Each participant was then assessed on the performance of a similar diagnostic ureteroscopy in a male cadaver. RESULTS: In medical students VR2 and cadaver performances correlated closely for several measured parameters (total time for task completion and overall global ratings score). In contrast, there was little correlation between the 2 performances in residents. Indeed, performance on the cadaver correlated more closely with the training level than VR2 scores. Despite VR training medical students were unable to perform cadaver ureteroscopy comparably to residents. CONCLUSIONS: For novice endoscopists performance on the simulator after training predicted operative (cadaver) performance and, thus, it may be useful for the education and assessment of physicians in training. However, VR training is unable to override the impact of clinical training, although it may help shorten the learning curve early in training.
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Competencia Clínica , Ureteroscopía , Urología/educación , Adulto , Cadáver , Simulación por Computador , Humanos , Estudiantes de MedicinaRESUMEN
PURPOSE: We describe the natural history of androgen independent prostate cancer (AIPC) in the modern prostate specific antigen (PSA) era. MATERIALS AND METHODS: Data from 160 patients diagnosed with AIPC between 1989 and 2002 were reviewed. No patient had received cytotoxic chemotherapy. Univariate and multivariate proportional hazards models were constructed to identify significant risk factors for cancer specific survival. Recursive partitioning analysis stratified patients into prognostic risk groupings. The types and frequencies of cancer specific complications per risk grouping were compared. RESULTS: The final prognostic risk model included nadir PSA on androgen deprivation therapy (p = 0.023), time to PSA recurrence (p = 0.006) and prostate specific antigen doubling time (p <0.01). Three highly independent risk groupings were identified. The observed median cancer specific survivals were 14.0 months (95% CI, 8.3-19.8), 38.4 months (95% CI, 26.9-49.9) and 89.1 months (95% CI, 69.0-109.2) for low, intermediate and high risk groupings, respectively (p <0.001). Patients in the low risk grouping experienced significantly fewer cancer specific complications (p = 0.003). CONCLUSIONS: This prognostic model stratified patients into 3 highly significant and independent risk groupings. A detailed PSA history alone is sufficient to risk stratify patients with AIPC.
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Neoplasias de la Próstata/mortalidad , Anciano , Anciano de 80 o más Años , Progresión de la Enfermedad , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Antígeno Prostático Específico/sangre , Medición de Riesgo , Análisis de SupervivenciaRESUMEN
OBJECTIVES: To identify the pretreatment variables that are predictive of response and the duration of response to deferred antiandrogen therapy in men with androgen-independent prostate cancer (AIPC). METHODS: A total of 375 patients receiving androgen deprivation therapy for advanced prostate cancer between 1977 and 2002 had medical records available for retrospective review. Of these 375 patients, 163 were diagnosed with AIPC. The inclusion criteria included (1) diagnosis of AIPC and (2) treatment with deferred antiandrogen therapy. AIPC was biochemically defined as two consecutive rises in the prostate-specific antigen (PSA) level during androgen deprivation therapy. The treatment response to deferred antiandrogen therapy was defined as a 50% or greater decline in the pretreatment PSA level. The prognostic value of various pretreatment parameters was determined with the appropriate statistical methods and tested with a Cox proportional hazards model. RESULTS: Of the 163 patients with AIPC, 36 were treated with deferred antiandrogen therapy. Of these 36 patients, 12 (33.3%) experienced a PSA response. The median PSA failure-free survival was 9.0 months (95% confidence interval 5.2 to 12.9). The only pretreatment variable predictive of a PSA response was the PSA doubling time (PSADT). The mean PSADT in responders was 12.7 months versus 7.5 months in nonresponders (P = 0.037). Moreover, PSADT was the only statistically significant variable on univariate analysis of PSA failure-free survival in responders (hazard ratio 0.202, 95% confidence interval 0.041 to 0.990, P = 0.049). No statistically significant difference was found in cancer-specific survival between responders and nonresponders (P = 0.1501). CONCLUSIONS: The PSADT predicted both the response and the duration of the response to deferred antiandrogen therapy in patients diagnosed with AIPC.