Andrew J. Stephenson

Predicting the Outcome of Salvage Radiation Therapy for Recurrent Prostate Cancer After Radical Prostatectomy

PURPOSE An increasing serum prostate-specific antigen (PSA) level is the initial sign of recurrent prostate cancer among patients treated with radical prostatectomy. Salvage radiation therapy (SRT) may eradicate locally recurrent cancer, but studies to distinguish local from systemic recurrence lack adequate sensitivity and specificity. We developed a nomogram to predict the probability of cancer control at 6 years after SRT for PSA-defined recurrence. PATIENTS AND METHODS Using multivariable Cox regression analysis, we constructed a model to predict the probability of disease progression after SRT in a multi-institutional cohort of 1,540 patients. RESULTS The 6-year progression-free probability was 32% (95% CI, 28% to 35%) overall. Forty-eight percent (95% CI, 40% to 56%) of patients treated with SRT alone at PSA levels of 0.50 ng/mL or lower were disease free at 6 years, including 41% (95% CI, 31% to 51%) who also had a PSA doubling time of 10 months or less or poorly differentiated (Gleason grade 8 to 10) cancer. Significant variables in the model were PSA level before SRT (P < .001), prostatectomy Gleason grade (P < .001), PSA doubling time (P < .001), surgical margins (P < .001), androgen-deprivation therapy before or during SRT (P < .001), and lymph node metastasis (P = .019). The resultant nomogram was internally validated and had a concordance index of 0.69. CONCLUSION Nearly half of patients with recurrent prostate cancer after radical prostatectomy have a long-term PSA response to SRT when treatment is administered at the earliest sign of recurrence. The nomogram we developed predicts the outcome of SRT and should prove valuable for medical decision making for patients with a rising PSA level.

Postoperative Nomogram Predicting the 10-Year Probability of Prostate Cancer Recurrence After Radical Prostatectomy

PURPOSE A postoperative nomogram for prostate cancer recurrence after radical prostatectomy (RP) has been independently validated as accurate and discriminating. We have updated the nomogram by extending the predictions to 10 years after RP and have enabled the nomogram predictions to be adjusted for the disease-free interval that a patient has maintained after RP. METHODS Cox regression analysis was used to model the clinical information for 1,881 patients who underwent RP for clinically-localized prostate cancer by two high-volume surgeons. The model was externally validated separately on two independent cohorts of 1,782 patients and 1,357 patients, respectively. Disease progression was defined as a rising prostate-specific antigen (PSA) level, clinical progression, radiotherapy more than 12 months postoperatively, or initiation of systemic therapy. RESULTS The 10-year progression-free probability for the modeling set was 79% (95% CI, 75% to 82%). Significant variables in the multivariable model included PSA (P = .002), primary (P < .0001) and secondary Gleason grade (P = .0006), extracapsular extension (P < .0001), positive surgical margins (P = .028), seminal vesicle invasion (P < .0001), lymph node involvement (P = .030), treatment year (P = .008), and adjuvant radiotherapy (P = .046). The concordance index of the nomogram when applied to the independent validation sets was 0.81 and 0.79. CONCLUSION We have developed and validated as a robust predictive model an enhanced postoperative nomogram for prostate cancer recurrence after RP. Unique to predictive models, the nomogram predictions can be adjusted for the disease-free interval that a patient has achieved after RP.

Gene expression profiling predicts clinical outcome of prostate cancer.

One of the major problems in management of prostate cancer is the lack of reliable genetic markers predicting the clinical course of the disease. We analyzed expression profiles of 12,625 transcripts in prostate tumors from patients with distinct clinical outcomes after therapy as well as metastatic human prostate cancer xenografts in nude mice. We identified small clusters of genes discriminating recurrent versus nonrecurrent disease with 90% and 75% accuracy in two independent cohorts of patients. We examined one group of samples (21 tumors) to discover the recurrence predictor genes and then validated the predictive power of these genes in a different set (79 tumors). Kaplan-Meier analysis demonstrated that recurrence predictor signatures are highly informative (P < 0.0001) in stratification of patients into subgroups with distinct relapse-free survival after therapy. A gene expression-based recurrence predictor algorithm was informative in predicting the outcome in patients with early-stage disease, with either high or low preoperative prostate-specific antigen levels and provided additional value to the outcome prediction based on Gleason sum or multiparameter nomogram. Overall, 88% of patients with recurrence of prostate cancer within 1 year after therapy were correctly classified into the poor-prognosis group. The identified algorithm provides additional predictive value over conventional markers of outcome and appears suitable for stratification of prostate cancer patients at the time of diagnosis into subgroups with distinct survival probability after therapy.

Predicting 15-Year Prostate Cancer Specific Mortality After Radical Prostatectomy

PURPOSE Long-term prostate cancer specific mortality after radical prostatectomy is poorly defined in the era of widespread screening. An understanding of the treated natural history of screen detected cancers and the pathological risk factors for prostate cancer specific mortality are needed for treatment decision making. MATERIALS AND METHODS Using Fine and Gray competing risk regression analysis we modeled clinical and pathological data, and followup information on 11,521 patients treated with radical prostatectomy at a total of 4 academic centers from 1987 to 2005 to predict prostate cancer specific mortality. The model was validated on 12,389 patients treated at a separate institution during the same period. Median followup in the modeling and validation cohorts was 56 and 96 months, respectively. RESULTS The overall 15-year prostate cancer specific mortality rate was 7%. Primary and secondary Gleason grade 4-5 (each p<0.001), seminal vesicle invasion (p<0.001) and surgery year (p=0.002) were significant predictors of prostate cancer specific mortality. A nomogram predicting 15-year prostate cancer specific mortality based on standard pathological parameters was accurate and discriminating with an externally validated concordance index of 0.92. When stratified by patient age at diagnosis, the 15-year prostate cancer specific mortality rate for pathological Gleason score 6 or less, 3+4, 4+3 and 8-10 was 0.2% to 1.2%, 4.2% to 6.5%, 6.6% to 11% and 26% to 37%, respectively. The 15-year prostate cancer specific mortality risk was 0.8% to 1.5%, 2.9% to 10%, 15% to 27% and 22% to 30% for organ confined cancer, extraprostatic extension, seminal vesicle invasion and lymph node metastasis, respectively. Only 3 of 9,557 patients with organ confined, pathological Gleason score 6 or less cancer died of prostate cancer. CONCLUSIONS Poorly differentiated cancer and seminal vesicle invasion are the prime determinants of prostate cancer specific mortality after radical prostatectomy. The prostate cancer specific mortality risk can be predicted with remarkable accuracy after the pathological features of prostate cancer are known.

Defining Biochemical Recurrence of Prostate Cancer After Radical Prostatectomy: A Proposal for a Standardized Definition

PURPOSE Prostate-specific antigen (PSA) defined biochemical recurrence (BCR) of prostate cancer is widely used for reporting the outcome of radical prostatectomy (RP). A standardized BCR definition is lacking, and overall progression-free probability and risk of subsequent metastatic disease progression may vary greatly depending on the PSA criterion used. Ten definitions of BCR were evaluated to identify the one that best explains metastatic progression. METHODS Of 3,125 patients who underwent RP at our institution since 1985, 75 developed distant metastasis during a median follow-up of 49 months. To predict metastasis progression, we modeled the clinical information using multivariable Cox regression analysis. BCR was included in the model as a time-dependent covariate, and separate models were developed for each definition. A goodness-of-fit (R2) statistic was used to determine the Cox model (and thereby the BCR definition) that best explained metastatic progression. RESULTS The 10-year progression-free probability ranged from 63% to 79%, depending on the BCR definition. The model containing BCR defined as a PSA of at least 0.4 ng/mL followed by another increase best explained metastatic progression (R2 = 0.21). This definition was also associated with a high probability of subsequent secondary therapy, continued PSA progression, and rapid PSA doubling time. CONCLUSION BCR defined as a PSA value of at least 0.4 ng/mL followed by another increase best explains the development of distant metastasis among 10 candidate definitions, after controlling for clinical variables and the use of secondary therapy. On the basis of this evidence, we propose that this definition be adopted as the standard for reporting the outcome of RP.

Prostate Cancer–Specific Mortality After Radical Prostatectomy for Patients Treated in the Prostate-Specific Antigen Era

PURPOSE The long-term risk of prostate cancer-specific mortality (PCSM) after radical prostatectomy is poorly defined for patients treated in the era of widespread prostate-specific antigen (PSA) screening. Models that predict the risk of PCSM are needed for patient counseling and clinical trial design. METHODS A multi-institutional cohort of 12,677 patients treated with radical prostatectomy between 1987 and 2005 was analyzed for the risk of PCSM. Patient clinical information and treatment outcome was modeled using Fine and Gray competing risk regression analysis to predict PCSM. RESULTS Fifteen-year PCSM and all-cause mortality were 12% and 38%, respectively. The estimated PCSM ranged from 5% to 38% for patients in the lowest and highest quartiles of predicted risk of PSA-defined recurrence, based on a popular nomogram. Biopsy Gleason grade, PSA, and year of surgery were associated with PCSM. A nomogram predicting the 15-year risk of PCSM was developed, and the externally validated concordance index was 0.82. Neither preoperative PSA velocity nor body mass index improved the models accuracy. Only 4% of contemporary patients had a predicted 15-year PCSM of greater than 5%. CONCLUSION Few patients will die from prostate cancer within 15 years of radical prostatectomy, despite the presence of adverse clinical features. This favorable prognosis may be related to the effectiveness of radical prostatectomy (with or without secondary therapy) or the low lethality of screen-detected cancers. Given the limited ability to identify contemporary patients at substantially elevated risk of PCSM on the basis of clinical features alone, the need for novel markers specifically associated with the biology of lethal prostate cancer is evident.

Adult UrologyOncology: Prostate/Testis/Penis/UrethraPredicting 15-Year Prostate Cancer Specific Mortality After Radical Prostatectomy

PURPOSE Long-term prostate cancer specific mortality after radical prostatectomy is poorly defined in the era of widespread screening. An understanding of the treated natural history of screen detected cancers and the pathological risk factors for prostate cancer specific mortality are needed for treatment decision making. MATERIALS AND METHODS Using Fine and Gray competing risk regression analysis we modeled clinical and pathological data, and followup information on 11,521 patients treated with radical prostatectomy at a total of 4 academic centers from 1987 to 2005 to predict prostate cancer specific mortality. The model was validated on 12,389 patients treated at a separate institution during the same period. Median followup in the modeling and validation cohorts was 56 and 96 months, respectively. RESULTS The overall 15-year prostate cancer specific mortality rate was 7%. Primary and secondary Gleason grade 4-5 (each p<0.001), seminal vesicle invasion (p<0.001) and surgery year (p=0.002) were significant predictors of prostate cancer specific mortality. A nomogram predicting 15-year prostate cancer specific mortality based on standard pathological parameters was accurate and discriminating with an externally validated concordance index of 0.92. When stratified by patient age at diagnosis, the 15-year prostate cancer specific mortality rate for pathological Gleason score 6 or less, 3+4, 4+3 and 8-10 was 0.2% to 1.2%, 4.2% to 6.5%, 6.6% to 11% and 26% to 37%, respectively. The 15-year prostate cancer specific mortality risk was 0.8% to 1.5%, 2.9% to 10%, 15% to 27% and 22% to 30% for organ confined cancer, extraprostatic extension, seminal vesicle invasion and lymph node metastasis, respectively. Only 3 of 9,557 patients with organ confined, pathological Gleason score 6 or less cancer died of prostate cancer. CONCLUSIONS Poorly differentiated cancer and seminal vesicle invasion are the prime determinants of prostate cancer specific mortality after radical prostatectomy. The prostate cancer specific mortality risk can be predicted with remarkable accuracy after the pathological features of prostate cancer are known.

Retroperitoneal Lymph Node Dissection for Nonseminomatous Germ Cell Testicular Cancer: Impact of Patient Selection Factors on Outcome

PURPOSE To investigate the impact of patient selection criteria on the outcome of patients with nonseminomatous germ cell testicular cancer (NSGCT) treated by primary retroperitoneal lymph node dissection (RPLND). Since 1999, our criteria have excluded patients with persistent postorchiectomy elevation of serum tumor markers (STM) or clinical stage (CS) IIB disease from RPLND. PATIENTS AND METHODS Between 1989 and 2002, 453 patients underwent primary RPLND at our institution for CS I to IIB NSGCT. Patient information was obtained from a prospective database. Retroperitoneal pathology and relapse rates were compared for patients treated before and after application of the current selection criteria in 1999. RESULTS By excluding patients with elevated STM or CS IIB disease after 1999, the proportion of pathologic stage II patients with low-volume (pN1) retroperitoneal disease increased significantly (40% before 1999 v 64% after 1999; P = .01), without significantly affecting the rate of retroperitoneal teratoma (21% v 22%, respectively; P = .89) or pathologic stage I disease (56% v 67%, respectively; P = .06). For patients who did not receive adjuvant chemotherapy, the 4-year progression-free probability improved significantly from 83% before 1999 (95% CI, 79% to 88%) to 96% after 1999 (95% CI, 91% to 100%; P = .005). Elevated postorchiectomy STM (P < .0001), clinical stage (P = .0002), and pre-1999 RPLND (P = .05) were independent pretreatment predictors of progression. CONCLUSION Excluding patients with CS IIB disease or elevated postorchiectomy STM from primary RPLND has had a favorable impact on the extent of retroperitoneal disease and has significantly reduced the risk of relapse after RPLND. For patients with normal STM and CS I to IIA disease, the low rate of systemic progression and 22% incidence of retroperitoneal teratoma supports RPLND as the preferred primary intervention.

Location, extent and number of positive surgical margins do not improve accuracy of predicting prostate cancer recurrence after radical prostatectomy.

PURPOSE Positive surgical margins increase the risk of biochemical recurrence after radical prostatectomy by 2 to 4-fold. The risk of biochemical recurrence may be influenced by the anatomical location and extent of positive surgical margins. In a multicenter study we analyzed the predictive usefulness of several subclassifications of positive surgical margins. MATERIALS AND METHODS The clinical information and followup data of 7,160 patients treated with radical prostatectomy alone at 1 of 3 institutions between 1995 and 2006 were modeled using Cox proportional hazards regression analysis for biochemical recurrence. Positive surgical margins were analyzed as solitary vs multiple, focal vs extensive and apical location vs other. The usefulness of these subclassifications was assessed by the improvement in predictive accuracy of nomograms containing these parameters compared to one in which the surgical margin was modeled simply as positive vs negative. RESULTS The 7-year progression-free probability was 60% in patients with positive surgical margins. A positive surgical margin was significantly associated with biochemical recurrence (HR 2.3, p <0.001) after adjusting for age, prostate specific antigen, pathological Gleason score, pathological stage and year of surgery. An increased risk of biochemical recurrence was associated with multiple vs solitary positive surgical margins (adjusted HR 1.4, p = 0.002) and extensive vs focal positive surgical margins (adjusted HR 1.3, p = 0.004) on multivariable analysis. However, neither parameter improved the predictive accuracy of a nomogram compared to one in which surgical margin status was modeled as positive vs negative (concordance index 0.851 vs 0.850 vs 0.850). CONCLUSIONS The number and extent of positive surgical margin significantly influence the risk of biochemical recurrence after radical prostatectomy. However, the empirical prognostic usefulness of subclassifications of positive surgical margins is limited.

American Society of Clinical Oncology Clinical Practice Guideline on Uses of Serum Tumor Markers in Adult Males With Germ Cell Tumors

PURPOSE To provide recommendations on appropriate uses for serum markers of germ cell tumors (GCTs). METHODS Searches of MEDLINE and EMBASE identified relevant studies published in English. Primary outcomes included marker accuracy to predict the impact of decisions on outcomes. Secondary outcomes included proportions of patients with elevated markers and statistical tests of elevations as prognostic factors. An expert panel developed consensus guidelines based on data from 82 reports. RESULTS No studies directly compared outcomes of decisions with versus without marker assays. The search identified few prospective studies and no randomized controlled trials; most were retrospective series. Lacking data on primary outcomes, most Panel recommendations are based on secondary outcomes (relapse rates and time to relapse). RECOMMENDATIONS The Panel recommended against using markers to screen for GCTs, to decide whether orchiectomy is indicated, or to select treatment for patients with cancer of unknown primary. To stage patients with testicular nonseminomas, the Panel recommended measuring three markers (alpha-fetoprotein [AFP], human chorionic gonadotropin [hCG], and lactate dehydrogenase [LDH]) before and after orchiectomy and before chemotherapy for those with extragonadal nonseminomas. They also recommended measuring AFP and hCG shortly before retroperitoneal lymph node dissection and at the start of each chemotherapy cycle for nonseminoma, and periodically to monitor for relapse. The Panel recommended measuring postorchiectomy hCG and LDH for patients with seminoma and preorchiectomy elevations. They recommended against using markers to guide or monitor treatment for seminoma or to detect relapse in those treated for stage I. However, they recommended measuring hCG and AFP to monitor for relapse in patients treated for advanced seminoma.