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Biomedical subjects

Luc Valiquette

Publications and source records attributed to Luc Valiquette.

At least 19 recordsLinked to original sources
PubMed2007

Development and external validation of an extended repeat biopsy nomogram.

PURPOSE: We hypothesized that the outcome of repeat biopsy could be accurately predicted. We tested this hypothesis in a contemporary cohort from 3 centers. MATERIALS AND METHODS: The principal cohort of 1,082 men from Hamburg, Germany was used for nomogram development as well as for internal 200 bootstrap validation in 721 and external validation in 361. Two additional external validation cohorts, including 87 men from Milan, Italy and 142 from Seattle, Washington, were also used. Predictors of prostate cancer on repeat biopsy were patient age, digital rectal examination, prostate specific antigen, percent free prostate specific antigen, number of previous negative biopsy sessions and sampling density. Multivariate logistic regression models were used to develop the nomograms. RESULTS: The mean number of previous negative biopsies was 1.5 (range 1 to 6) and the mean number of cores at final repeat biopsy was 11.1 (range 10 to 24). Of the men 370 (30.2%) had prostate cancer. On multivariate analyses all predictors were statistically significant (p < or =0.028). After internal validation the nomogram was 76% accurate. External validation showed 74% (Hamburg), 78% (Milan) and 68% (Seattle) accuracy. CONCLUSIONS: Relative to the previous nomograms (10 predictors or 71% accuracy) our tool relies on fewer variables (6) and shows superior accuracy in European men. Accuracy in American men is substantially lower. Racial, clinical and biochemical differences may explain the observed discrepancy in predictive accuracy.

Adult↗
PubMed2006

Development and internal validation of preoperative transition zone prostate cancer nomogram.

OBJECTIVES: Up to 20% of men may harbor a transition zone (TZ) prostate cancer (PCa) at radical prostatectomy (RP). TZ PCa may be associated with more favorable RP pathologic findings than peripheral zone (PZ) PCa. To identify these men, we developed a model capable of predicting the probability of TZ PCa at RP. METHODS: The study cohort consisted of 945 consecutive men treated with RP, with clinical stage, prostate-specific antigen (PSA) level, and detailed biopsy and RP pathology data available. The preoperative variables were used as predictors in the multivariate logistic regression models to predict the rate of TZ PCa at RP. PCa was defined as a TZ tumor when more than 50% of the planimetrically measured tumor volume was situated within the TZ. Regression coefficients were used to develop nomograms, which were subjected to 200 bootstrap resamples to reduce overfit bias. RESULTS: TZ PCa at the final pathologic examination was recorded in 110 patients (11.6%). After 200 bootstraps, the most parsimonious and most accurate nomogram was 77.3% accurate in predicting the probability of TZ PCa. CONCLUSIONS: This nomogram is ideally suited to identify patients with markedly elevated, nearly metastatic serum PSA levels who harbor a TZ tumor that is highly treatable by RP.

Adult↗
PubMed2006

Body mass index does not improve the ability to predict biochemical recurrence after radical prostatectomy.

PURPOSE: To test whether body mass index (BMI) improves pre- or post-operative biochemical recurrence (BCR) predictions after radical prostatectomy. MATERIALS AND METHODS: Pre- and post-operative data were available in 2416 and 2499 men, respectively. Cox regression models addressed the association between BMI and the rate of BCR after adjusting for pre- and post-operative predictors. Predictive accuracy was quantified using Harrell's concordance index, with and without BMI and subjected to 200 bootstraps to reduce overfit bias. Differences in predictive accuracy were compared using the Mantel-Haenszel test. RESULTS: After adjusting for either pre- or post-operative variables, increasing BMI was a statistically independent risk factor of BCR in both models (both p0.003). Its addition to pre- and post-operative variables respectively increased predictive accuracy measures from 69.6 to 70.2% (+0.6%, p=0.7) and from 78.1 to 78.4% (+0.3%, p=0.8). CONCLUSION: Our data emphasise that despite its significance, inclusion of BMI into models, to predict BCR, does not improve their accuracy.

Body Mass Index↗
PubMed2006

Development and external validation of an extended 10-core biopsy nomogram.

OBJECTIVES: To test the accuracy of a previously externally validated sextant biopsy nomogram in referred men exposed to > or =10 or more biopsy cores. Moreover, we explored the hypothesis that a more accurate predictive tool could be developed. METHODS: Previous nomogram predictors (age, digital rectal examination, prostate-specific antigen, and percent free PSA) were used to assess the accuracy of our previous nomogram in a cohort consisting of 2900 men referred for prostatic evaluation. Moreover, these variables were complemented with sampling density (SD) (i.e., ratio of gland volume and the number of planned biopsy cores) within multivariable logistic regression models (LRM) predicting presence of prostate cancer (pCA) on the initial 10 or more core biopsy. The LRMs were used to develop and internally validate (200 bootstrap resamples) a new nomogram in 1162 men from Hamburg, Germany. The LRMs' external validity was tested in three separate cohorts (Hamburg, n=582; Milan, n=961; Seattle, n=195). RESULTS: The contemporary external validation of the previously validated sextant nomogram demonstrated 70% accuracy. Internal validation of the new nomogram demonstrated 77% accuracy, and external cohorts demonstrated 73-76% accuracy. CONCLUSIONS: In the era of extended biopsy schemes, previously developed predictive models are less accurate in predicting the probability of pCA on initial biopsy. We developed a new tool that allows obtaining more accurate predictions. Moreover, before biopsy, it also allows defining the ideal ratio between gland volume and the number of planned biopsy cores that would yield the ideal biopsy rate.

Adult↗
PubMed2006

Complications and other surgical outcomes associated with extended pelvic lymphadenectomy in men with localized prostate cancer.

OBJECTIVES: More-extensive pelvic lymph node dissection (PLND) may be associated with a higher rate of complications and a longer hospital stay than more limited PLND. METHODS: Before radical retropubic prostatectomy, PLNDs were performed in 963 patients. Of these, 767 (79.6%) had >or=10 lymph nodes removed and examined (extended PLND [ePLND]), while 1-9 nodes (limited PLND [lPLND]) were removed in the remaining 196 (20.4%). Limits included external iliac, obturator, internal iliac, and iliac bifurcation. PLND-related complications and the length of hospital stay were recorded prospectively and analyzed according to the extent of PLND. RESULTS: In patients subjected to ePLND, the overall rate of complications was 19.8% versus 8.2% in those treated with lPLND (p<0.001). In individual analyses of specific complications, only the lymphocele rate was significantly higher after ePLND (10.3% vs 4.6%; p=0.01). Similarly, ePLND translated into a longer hospital stay (9.9 vs 8.2 d; p<0.001). These differences persisted when adjustment was made for prostate-specific antigen and either clinical or pathologic tumor characteristics. CONCLUSIONS: Our data indicate that, even in the hands of experienced urologic surgeons, ePLNDs are associated with higher complication rates and longer hospital stay. These detriments need to be taken into account when the staging benefit associated with ePLND is considered.

Adult↗
PubMed2006

A nomogram for staging of exclusive nonobturator lymph node metastases in men with localized prostate cancer.

OBJECTIVES: Some patients with localized prostate cancer are at risk of nonobturator lymph node invasion (NOLNI) and may require an extended pelvic lymph node dissection (ePLND). We explored the rate of exclusive NOLNI and developed a nomogram to predict it. MATERIAL AND METHODS: We mapped all ePLND specimens according to their anatomic location (obturator, external iliac, internal iliac lymph nodes) and assessed the location-specific rate of LNI in 565 patients. A multivariate logistic regression-based nomogram predicting NOLNI was then internally validated with 200 bootstrap resamples. RESULTS: Overall, 11.1% (63 of 565) had LNI and 21 (3.7%) had exclusive NOLNI. The nomogram predicting exclusive NOLNI was 80.2% accurate. The nomogram's negative predictive value was 99%, when it predicted 0-10% probability of NOLNI. This approach could allow the omission of an ePLND in 350 of 565 (61.9%) patients and still correctly stage 85.8% of NOLNI cases. CONCLUSIONS: Our nomogram-based approach offers the possibility of identifying men who are at virtually zero risk of exclusive NOLNI. In these men, an ePLND may be safely avoided.

Adult↗
PubMed2006

Outcomes research: a methodologic review.

OBJECTIVES: We explored the history and conceptual trends of outcomes research. METHODS: We described different aspects of this field, after dividing it into conceptually distinct strata. RESULTS: Outcomes research can be divided into macro, meso and micro levels. Each level is further subdivided. Macro-level research targets cost and health care utilization, as well as racial, ethnic and geopolitical population health determinants. Meso-level studies address effectiveness, variability, disease impact, clinical modeling and program evaluation studies. Finally, micro-level studies address all aspects of direct patient-clinician decision-making. CONCLUSIONS: An explosion of outcomes research has occurred in the past decades. Wide access to information technology, data sharing and collaborative efforts between researchers represent some of the ingredients that did and will continue to fuel that growth.

Humans↗
PubMed2006

Validation of a nomogram predicting the probability of lymph node invasion among patients undergoing radical prostatectomy and an extended pelvic lymphadenectomy.

INTRODUCTION: Our goal was to develop and internally validate a nomogram for prediction of lymph node invasion (LNI) in patients with clinically localized prostate cancer undergoing extended pelvic lymphadenectomy (ePLND). METHODS: 602 consecutive patients (mean age 65.8 years) underwent an ePLND, where 10 or more nodes were removed. PSA was 1.1-49.9 (median 7.2). Clinical stages were: T1c in 55.6%, T2 in 41.4% and T3 in 3%. Biopsy Gleason sums were: 6 or less in 66%, 7 in 25.4%, 8-10 in 8.6%. Multivariate logistic regression models tested the association between all of the above predictors and LNI. Regression-based coefficients were used to develop a nomogram predicting LNI and 200 bootstrap resamples were used for internal validation. RESULTS: Mean number of lymph nodes removed was 17.1 (range 10-40). LNI was detected in 66 patients (11.0%). Univariate predictive accuracy for total PSA, clinical stage and biopsy Gleason sum was 63%, 58% and 73%, respectively. A nomogram based on clinical stage, PSA and Biopsy Gleason sum demonstrated bootstrap-corrected predictive accuracy of 76%. CONCLUSIONS: A nomogram based on pre-treatment PSA, clinical stage and biopsy Gleason sum can highly accurately predict LNI at ePLND.

Aged↗
PubMed2006

Prostate specific-antigen distribution in asymptomatic Canadian men with no clinical evidence of prostate cancer.

OBJECTIVE: To examine prostate specific-antigen (PSA) levels and percentage free/total PSA (f/tPSA) distributions as well as digital rectal examination (DRE) profiles in asymptomatic Canadian men with no established prostate cancer diagnosis, as recent data indicate that a man's risk of developing prostate cancer is higher if his baseline PSA level is above the median for his age group. SUBJECTS AND METHODS: We used data obtained during an early prostate cancer-detection event. An invitation to an onsite DRE, PSA level and f/tPSA assessment was accepted by 313 men. Serum PSA level and f/tPSA were measured before the DRE. A suspicious DRE and/or PSA level of > or = 2.5 ng/mL or f/tPSA of < or = 15% represented indications for a systematic 12-core ultrasonography-guided prostate biopsy. RESULTS: Of all the 313 men, most (235, 75%) had PSA levels of 0.01-1.53 ng/mL and an f/tPSA of >15% (285, 91.1%). The median (range) PSA level was 0.8 (0-34.2) ng/mL and f/tPSA was 27.4 (6.7-100)%. Age-specific median PSA levels and f/tPSA were, respectively, 0.7, 0.9, 1.0, 1.5 ng/mL and 31%, 27%, 26%, 25% for men aged 40-49, 50-59, 60-69 and 70-79 years. A suspicious DRE was recorded in 55 (17.6%) men, with eight (8.8%), 26 (20.0%), 14 (20.6%), and seven (28.9%) having suspicious DRE findings according to above age categories. Overall, seven (2.2%) prostate cancers were detected. CONCLUSION: The median age-specific baseline PSA levels and f/tPSA represent valuable indicators of prostate cancer risk. The population-specific baseline median PSA level should not be >1.0 ng/mL and the baseline f/tPSA should be >30%. Men with values outside of these ranges should be considered at greater risk of prostate cancer.

Adult↗
PubMed2006

Significant upgrading affects a third of men diagnosed with prostate cancer: predictive nomogram and internal validation.

OBJECTIVE: To explore the rate of significant upgrading from biopsy to radical prostatectomy (RP) specimens in a contemporary cohort, and to develop a prognostic model capable of predicting the probability of significant upgrading, as previous reports indicate that up to 43% of men with low-grade prostate cancer at biopsy will be diagnosed with high-grade cancer at RP. PATIENTS AND METHODS: The study cohort comprised 4789 men (median age 63 years, range 39-82) treated with RP, with available clinical stage, prostate-specific antigen levels, biopsy and RP Gleason sum values. These variables were used as predictors in multivariate logistic regression models (LRMs) addressing the rate of significant Gleason sum upgrading, defined as a Gleason sum increase either from < or = 6 to > or = 7 or from 7 to > or = 8 between the biopsy and RP specimens. Regression coefficients were used to develop and validate (200 bootstrap re-samples) a nomogram predicting significant biopsy Gleason sum upgrading. RESULTS: Significant biopsy Gleason sum upgrading was recorded in 1349 (28.2%) patients. In multivariate LRMs, all predictors were highly significant (all P < 0.001). The bootstrap-corrected accuracy of the nomogram predicting the probability of significant Gleason sum upgrading between biopsy and RP specimens was 75.7%. CONCLUSION: Our nomogram might prove highly useful when the possibility of a more aggressive Gleason variant could change the treatment options.

Adult↗
PubMed2006

Efficacy of tadalafil in men with erectile dysfunction naïve to phosphodiesterase 5 inhibitor therapy compared with prior responders to sildenafil citrate.

INTRODUCTION: Tadalafil, an inhibitor of phosphodiesterase 5 (PDE5), is indicated for treatment of erectile dysfunction. Most tadalafil clinical trials excluded patients with unsuccessful prior treatment with sildenafil citrate (sildenafil). AIM: This retrospective analysis of pooled data from 14 tadalafil clinical trials examines the effect of this exclusion by comparing efficacy results in 1,349 patients without prior sildenafil use (naïve, presumably a mixture of potential responders and nonresponders) with efficacy results in 1,440 patients previously responsive to sildenafil (prior responders). MAIN OUTCOME MEASURES: Efficacy measures included the International Index of Erectile Function (IIEF) erectile function (EF) domain, overall satisfaction (OS), and intercourse satisfaction (IS) domain scores; Sexual Encounter Profile (SEP) diary questions 2 through 5 (SEP2 [successful penetration], SEP3 [successful intercourse], SEP4 (satisfaction with hardness of erection), and SEP5 [overall satisfaction with the sexual experience]); and a Global Assessment Question (GAQ1) (13/14 trials) about erection improvement. Efficacy was compared using analysis of covariance (IIEF and SEP) and logistic regression (GAQ1) models. METHODS: After a 4-week, treatment-free, run-in period, patients in 14 double-blind, placebo-controlled, parallel-group trials were treated with tadalafil 10 mg, tadalafil 20 mg, or placebo for 12 weeks (dosed as needed before sexual activity, no more than once daily). RESULTS: Tadalafil improved erectile function compared with placebo (P < 0.001) in naïve patients and sildenafil prior responders for all efficacy measures. For most efficacy outcomes, responses in the naïve group (probable mix of responders and nonresponders) were not statistically different from responses in the prior-responder group (P >or= 0.10). CONCLUSIONS: The similar responses of these two patient groups observed in this post hoc analysis suggest, but do not confirm, that exclusion of sildenafil nonresponders in previously reported tadalafil clinical trials may not have substantially affected efficacy outcomes. Tadalafil improved erectile function in patients naïve to PDE5 inhibitor therapy and in patients who previously responded to sildenafil therapy.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2006

Prostate cancer nomograms are superior to neural networks.

INTRODUCTION: Several nomograms have been developed to predict PCa related outcomes. Neural networks represent an alternative. METHODS: We provide a descriptive and an analytic comparison of nomograms and neural networks, with focus on PCa detection. RESULTS: Our results indicate that nomograms have several advantages that distinguish them from neural networks. These are both quantitative and qualitative. CONCLUSION: In the field of PCa detection, nomograms appear to outweigh the benefits of neural networks. However, the neural network methodology represents a valid alternative, which should not be underestimated.

Forecasting↗
PubMed2006

Therapeutic approach to hormone-refractory prostate cancer.

Over 60 years ago, Huggins and Hodges discovered androgen deprivation as an effective first-line therapy for metastatic prostate cancer. This leads to significant cancer control but in almost all men prostate cancer ultimately progresses to a hormone-refractory (HRPC) state resulting in significant morbidity and eventual death. In 2004, two landmark studies using docetaxel based chemotherapy demonstrated, for the first time, a survival advantage in HRPC. This has set a new standard of care for this disease. In addition, treatment with the bisphosphonate zoledronic acid has been shown to significantly reduce bone complications in metastatic HRPC. Building on these advances, several new docetaxel/zoledronic acid based combinations as well as new targeted therapies are under development. Introducing these effective therapies earlier in high risk patients is also under investigation to further improve outcomes.

Algorithms↗
PubMed2005

Development and validation of a nomogram predicting the outcome of prostate biopsy based on patient age, digital rectal examination and serum prostate specific antigen.

PURPOSE: We developed and validated a nomogram which predicts presence of prostate cancer (PCa) on needle biopsy. MATERIALS AND METHODS: We used 3 cohorts of men who were evaluated with sextant biopsy of the prostate and whose presenting prostate specific antigen (PSA) was not greater than 50 ng/ml. Data from 4,193 men from Montreal, Canada were used to develop a nomogram based on age, digital rectal examination (DRE) and serum PSA. External validation was performed on 1,762 men from Hamburg, Germany. Data from these men were subsequently used to develop a second nomogram in which percent free PSA (%fPSA) was added as a predictor. External validation was performed using 514 men from Montreal. Both nomograms were based on multivariate logistic regression models. Predictive accuracy was evaluated with areas under the receiver operating characteristic curve and graphically with loess smoothing plots. RESULTS: PCa was detected in 1,477 (35.2%) men from Montreal, 739 (41.9%) men from Hamburg and 189 (36.8%) men from Montreal. In all models all predictors were significant at 0.05. Using age, DRE and PSA external validation AUC was 0.69. Using age, DRE, PSA and %fPSA external validation AUC was 0.77. CONCLUSIONS: A nomogram based on age, DRE, PSA and %fPSA can highly accurately predict the outcome of prostate biopsy in men at risk for PCa.

Adolescent↗
PubMed2005

Sustained efficacy and safety of vardenafil for treatment of erectile dysfunction: a randomized, double-blind, placebo-controlled study.

OBJECTIVE: To evaluate the reliability, efficacy, and safety of vardenafil, 10 mg, for patients with erectile dysfunction. PATIENTS AND METHODS: Vardenafil-naive patients completed a 4-week treatment-free run-in phase and a 1-week single-dose vardenafil (10 mg) open-label challenge phase. Responders to vardenafil in the challenge phase were randomized to 12 weeks of double-blind, fixed-dose treatment with vardenafil at 10 mg or placebo. Diary responses to Sexual Encounter Profile (SEP) questions about erections and attempts at sexual activity were collected after 4, 8, and 12 weeks of randomized treatment. Adverse events were monitored throughout the study. RESULTS: During the open-label challenge phase, the proportions of patients with a first-time success for penetration (SEP2) and maintenance of erection (SEP3) were 87% and 74%, respectively. Of 600 patients challenged with a single dose of vardenafil at 10 mg, 260 were randomized to vardenafil and 263 to placebo. During the double-blind phase, the reliability of penetration and maintenance rates for patients successful during the challenge phase were significantly greater with vardenafil compared with placebo (83.4% vs 55.8% [SEP2] and 76.6% vs 42.1% [SEP3], respectively). At week 12, patients in the vardenafil group had a consistently higher least squares mean (SE) on the erectile function domain score of the International Index of Erectile Function than patients in the placebo group (23.5 [0.4] vs 15.8 [0.4], respectively [last observation carried forward]) and a greater proportion of positive responses to the Global Assessment Question (80.8% vs 32.3%, respectively [last observation carried forward]) at each assessment (Pc.001). Vardenafil was generally well tolerated; most adverse events were mild to moderate, with headache and flushing reported most frequently. CONCLUSION: During this 12-week study, vardenafil produced consistently higher reliability of penetration and maintenance of erection rates compared to placebo and was generally well tolerated in patients with erectile dysfunction.

Double-Blind Method↗
PubMed2005

Exploration of health-related quality of life areas that may distinguish between continent diversion and ileal conduit patients.

OBJECTIVES: We explored the specific impact of urinary diversion type on HRQOL in men after cystectomy for bladder cancer. Our intent was to provide a basis for the development of a diversion-specific instrument. METHODS: We invited 13 ileal conduit and 12 orthotopic urinary diversion (neo-bladder) male patients to several open-ended interviews. We explored HRQOL domains that may have been affected by cystectomy and urinary diversion, and that could then be used to form a basis for a diversion-specific HRQOL measure. RESULTS: The average age of neo-bladder patients was 59 versus 65 years for ileal conduit patients. We identified 10 HRQOL domains, ranging from involuntary urine leakage to dietary modifications, which were recognized as important by ileal conduit and neobladder patients. Within each domain, a sufficient amount of overlap existed to allow developing a measure that might be applied to both groups of patients. CONCLUSIONS: Ten HRQOL domains were identified as important by ileal conduit and neobladder patients. These demonstrated a significant amount of overlap between conduit and neobladder patients. Potentially, these domains could be used to develop scales for distinguishing between conduit and neobladder-specific HRQOL detriments.

Aged↗
PubMed2005

Validation of 1997 Partin Tables' lymph node invasion predictions in men treated with radical prostatectomy in Montreal Quebec.

OBJECTIVE: The accuracy of 1997 Partin Tables' lymph node invasion (LNI) predictions exhibits important variability in different testing populations. We explored the LNI predictive accuracy in radical prostatectomy (RP) patients from Montreal, Canada. Moreover, we assessed the extent of change in predictive accuracy related to a modification of PSA coding from categorical to continuous. METHODS: We used pretreatment serum PSA, clinical stage, and biopsy Gleason sum from 537 men treated with RP to compare predicted and observed rates of LNI. Accuracy was quantified with receiver-operating characteristics curves. RESULTS: Accuracy was 0.760 in 369 evaluable patients, when categorically coded pretreatment PSA (0-4, 4.1-10, 10.1-20, 20.1+) was combined with clinical stage and biopsy Gleason sum. A 2.7% accuracy increase was noted when categorically coded PSA was replaced with continuously coded values. CONCLUSION: Partin Tables' LNI predictions showed comparable accuracy to a community-based sample from the United States (0.766), and to a recent, multi-institutional sample (0.740). However, accuracy was lower than reported in internal (0.818), and external (0.837) academic, validation cohorts. Accuracy of LNI predictions was appreciably higher, when continuously coded PSA was used.

Humans↗