Biomedical subjects

Pierre I Karakiewicz

Publications and source records attributed to Pierre I Karakiewicz.

At least 19 recordsLinked to original sources

PubMed2007

Tumour volume and high grade tumour volume are the best predictors of pathologic stage and biochemical recurrence after radical prostatectomy.

INTRODUCTION: Our goal was to examine to what extent tumour volume (TV) and percentage of high grade tumour volume (%HGTV) affect the rate of positive surgical margins and the rate of biochemical recurrence after radical prostatectomy. MATERIALS AND METHODS: TV and %HGTV were routinely planimetrically quantified in a cohort of 780 consecutive patients. Mean follow-up was 46.7 months. Multivariable regression models addressed two separate endpoints: positive surgical margins and biochemical recurrence. The increase in model predictive accuracy related to the addition of TV and %HGTV to radical prostatectomy stage and grade was assessed, after 200 bootstrap resamples to reduce overfit bias. RESULTS: In multivariable logistic regression models addressing positive surgical margins rate, predictive accuracy increased by 1.9% (p<0.001) when TV was added to other covariates. No further increment was noted when %HGTV was added (p=0.3). In multivariable Cox regression models addressing biochemical recurrence, accuracy increased by 0.6% (p=0.002) when TV was added and an additional increase of 0.7% was recorded when %HGTV (p<0.001) was added. CONCLUSION: Tumour bulk reflected by TV affects local cancer control rate, which is reflected in the rate of positive surgical margins. Conversely, high grade cancer determines the rate of biochemical recurrence. These two variables represent the most powerful predictors of cancer control in men treated for localised prostate cancer. Moreover, they increase the ability of established predictors to predict the outcomes of interest. In consequence, they warrant consideration in future predictive and prognostic tools.

Adult↗

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

Renal cell carcinoma with nodal metastases in the absence of distant metastatic disease: prognostic indicators of disease-specific survival.

OBJECTIVES: Outcome of patients with exclusive renal cell carcinoma (RCC) nodal metastases without distant metastases is not extensively described. We explored the ability of standard risk factors such as tumour size, Fuhrman grade, histologic subtype and symptom classification to predict renal cell carcinoma-specific survival (RCC-SS). METHODS: Analyses targeted 171 patients with RCC nodal metastases and absence of distant metastases. Univariable, multivariable, and predictive accuracy analyses addressed RCC-SS with the intent of identifying independent and most informative predictors of RCC-SS in this cohort of patients. RESULTS: Median RCC-SS was 2.3 yr. Symptom classification (61.3%, p<0.001) demonstrated the highest univariable accuracy. In multivariable analyses, symptom classification contributed the most to the combined predictive accuracy of all variables (+4.2%, p<0.001), followed by Fuhrman grade (+2.3%) and histologic subtype (+1.0%). CONCLUSIONS: Renal cell carcinoma-specific survival of patients with exclusive nodal metastases may show important variability. In presence of systemic symptoms, survival is extremely poor. Substantially better survival may be expected in patients with local or no symptoms. This observation has important implications when adjuvant therapies are considered.

Adolescent↗

PubMed2006

Prediction of pathological stage is inaccurate in men with PSA values above 20 ng/mL.

INTRODUCTION: We hypothesized that either very low (0-2.5 ng/mL) or very high (>20 ng/mL) PSA values may limit the accuracy of pathological stage predictions. To test this hypothesis, we examined 5193 consecutive patients subjected to radical prostatectomy (RP) for localized prostate cancer (PCa). MATERIAL AND METHODS: Patients were divided into three cohorts according to their pre-treatment PSA value: </=2.5 (n=331), 2.51-20 (n=4545) and >20 ng/mL (n=317). Subsequently in each cohort, the ability of PSA, clinical stage and biopsy Gleason sum was tested in multivariable logistic regression models predicting three separate endpoints: extracapsular extension (ECE), seminal vesicle invasion (SVI) and lymph node invasion (LNI). Predictive accuracy represented the performance benchmark. All models were adjusted for year of surgery and subjected to 200 bootstrap resamples to reduce overfit bias. RESULTS: For PSA </=2.5 ng/mL, predictive accuracy was 76.7%, 72.3% and 82.8% for respectively ECE, SVI and LNI. For PSA 2.51-20 ng/mL, the predictive accuracy for the same endpoints was 67.8%, 77.4% and 81.6%. Finally, for PSA >20 ng/mL, predictive accuracy was 63.6%, 63.7% and 70.6%. CONCLUSIONS: The ability to predict pathological stage in patients with PSA values in excess of 20 ng/mL significantly decreased, compared to patients with lower PSA values. Therefore, accurate staging of these patients may require alternative markers or staging schemes.

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

Prostate cancer-specific survival in men treated with hormonal therapy after failure of radical prostatectomy.

OBJECTIVES: We hypothesized that prostate cancer-specific survival (PCaSS) could be accurately predicted in men in whom radical prostatectomy (RP) failed and who received hormonal therapy (HT) after RP failure. METHODS: Between 1954 and 1994, 752 consecutive patients underwent RP without neoadjuvant therapy. Of those, 114 patients (15.2%) received HT at RP failure and represent the focus of this analysis. Cox regression models and a nomogram targeted PCaSS. The main predictor was timing of HT initiation: at prostate-specific antigen (PSA) versus local versus distant recurrence. Covariates included age at HT, pathologic T stage, surgical margin status and Gleason sum at RP, use of adjuvant or salvage radiation, and time from RP to HT. RESULTS: Mean and median follow-up periods were 5.1 and 3.9 yr; 70 deaths were recorded, of which 45 (39.8%) were due to PCa. At 1, 5, 10, and 15 yr, the estimates of PCaSS were, respectively, 97.1%, 68.3%, 49.3%, and 30.2% (median, 9.8 yr). Younger men and those with HT initiated at the time of distant recurrence had lower PCaSS. A nomogram predicting PCaSS at 2, 3, 4, and 5 yr after RP was developed and demonstrated 66% accuracy after 200-bootstrap internal validation. CONCLUSION: Despite RP failure, half the patients can expect to survive for 10 yr. The nomogram can help in discriminating between those with better versus worse PCaSS, better than relying on most educated guesses.

Aged↗

PubMed2006

Nomograms provide improved accuracy for predicting survival after radical cystectomy.

AIMS: To develop multivariate nomograms that determine the probabilities of all-cause and bladder cancer-specific survival after radical cystectomy and to compare their predictive accuracy to that of American Joint Committee on Cancer (AJCC) staging. METHODS: We used Cox proportional hazards regression analyses to model variables of 731 consecutive patients treated with radical cystectomy and bilateral pelvic lymphadenectomy for bladder transitional cell carcinoma. Variables included age of patient, gender, pathologic stage (pT), pathologic grade, carcinoma in situ, lymphovascular invasion (LVI), lymph node status (pN), neoadjuvant chemotherapy (NACH), adjuvant chemotherapy (ACH), and adjuvant external beam radiotherapy (AXRT). Two hundred bootstrap resamples were used to reduce overfit bias and for internal validation. RESULTS: During a mean follow-up of 36.4 months, 290 of 731 (39.7%) patients died; 196 of 290 patients (67.6%) died of bladder cancer. Actuarial all-cause survival estimates were 56.3% [95% confidence interval (95% CI), 51.8-60.6%] and 42.9% (95% CI, 37.3-48.4%) at 5 and 8 years after cystectomy, respectively. Actuarial cancer-specific survival estimates were 67.3% (62.9-71.3%) and 58.7% (52.7-64.2%) at 5 and 8 years, respectively. The accuracy of a nomogram for prediction of all-cause survival (0.732) that included patient age, pT, pN, LVI, NACH, ACH, and AXRT was significantly superior (P=0.001) to that of AJCC staging-based risk grouping (0.615). Similarly, the accuracy of a nomogram for prediction of cancer-specific survival that included pT, pN, LVI, NACH, and AXRT (0.791) was significantly superior (P=0.001) to that of AJCC staging-based risk grouping (0.663). CONCLUSIONS: Multivariate nomograms provide a more accurate and relevant individualized prediction of survival after cystectomy compared with conventional prediction models, thereby allowing for improved patient counseling and treatment selection.

Adult↗

PubMed2006

Advanced age is associated with poorer bladder cancer-specific survival in patients treated with radical cystectomy.

OBJECTIVE: Bladder cancer (BCa) is a disease of older persons, the incidence of which is expected to increase as the population ages. There is controversy, however, regarding the outcomes of radical cystectomy (RC), the gold standard treatment of high-risk BCa, in patients of advanced chronological age. The aim of our study was to assess the impact of patient age on pathological characteristics and recurrence-free and disease-specific survival following RC. METHODS: The records of 888 consecutive patients who underwent RC for transitional cell carcinoma (TCC) were reviewed. Age at RC was analyzed both as a continuous (yr) and categorical (< or =60 yr old, n=240; 60.1-70 yr old, n=331; 70.1-80 yr old, n=266; >80 yr old, n=51) variable. Logistic regression and survival analyses were performed. RESULTS: Higher age at RC, analyzed as a continuous or categorical variable, was associated with extravesical disease and pathological upstaging (all p<0.02). Older patients were less likely to receive postoperative chemotherapy (< or =60 yr: 32% vs. >80 yr: 14%, p=0.008). In both pre- and postoperative multivariate models, higher age at RC as a categorical variable was associated with BCa-specific survival (p<0.05). Patients >80 yr old had a significantly greater risk of disease recurrence than patients aged < or =60 yr (p<0.05). CONCLUSION: Greater patient age at the time of RC for BCa is independently associated with adverse outcomes. Better understanding of factors associated with postoperative outcomes in this growing segment of the population is necessary. Prospective corroboration and further refinement of similar analyses in other large datasets is needed.

Adult↗

PubMed2006

Sunitinib relieves renal cell carcinoma spinal cord compression.

A 66-year-old previously healthy female was diagnosed with renal cell carcinoma (RCC) metastic to the 4th, 6th and 12th thoracic vertebrae. Despite external beam radiotheraphy (20G in 5 fractions), she progressed to spinal cord compression within 4 weeks and was wheelchair bound. Radiation and surgery were not considered suitable, but sunitinib was initiated. After two 6-week sunitinib cycles, she is fully ambulatory. She reports grade I fatigue and occasional epistaxis, as sole side effects. This case demonstrates that despite the rapid progression of the disease, which escaped the effect of radiation within four weeks, sunitinib resulted in complete clinical symptom resolution, which was confirmed radiographically. Moreover, it appears that the novel therapies for metastatic RCC may restore quality and quantity of life to many of those, whose disease previously appeared too advanced to treat.

Aged↗

PubMed2006

Surgical volume is related to the rate of positive surgical margins at radical prostatectomy in European patients.

OBJECTIVE: To assess the association between surgical volume (SV) and the rate of positive surgical margins (PSM) after radical prostatectomy (RP) in a large single-institution European cohort of patients. PATIENTS AND METHODS: In all, 2402 men had a RP by a group of 11 surgeons, all of whom were trained by the surgeon with the highest SV; all surgeons used the same surgical technique. Variables assessed before RP were prostate-specific antigen (PSA) level, clinical stage and biopsy Gleason sum; variables assessed after RP were PSA level, extracapsular extension, seminal vesicle invasion, lymph node invasion and pathological Gleason sum. These were used to predict the rate of PSM in models before or after RP. Multivariate models were complemented with SV to test its independent and multivariate statistical significance and to quantify its impact on the model's overall (and 200 bootstrap-corrected) predictive accuracy. RESULTS: The mean (range) SV was 201 (1-1293) RPs; the mean (median, range) rate of PSM was 20.2 (21.4, 0-32.9)%. In multivariate models, SV was a highly statistically significant independent predictor of PSM (P < 0.001) and increased the predictive accuracy in multivariate models both before (2.0%) and after RP (1.5%, both P < 0.001). However, when the surgeon with the highest SV, who contributed to 1293 cases, was removed from the analyses, the multivariate independent prediction and the gains in predictive accuracy related to adding SV, disappeared in the models both before (P = 0.9, accuracy gain 0.1%) and after (P = 0.4, accuracy gain - 0.3%) RP. CONCLUSIONS: These results indicate that patients treated by surgeons with a very high volume can expect to have a significantly lower rate of PSM, after accounting for clinical and pathological case-mix differences. However, SV is not a predictor of PSM when analyses are restricted to intermediate- and low-volume surgeons.

Clinical Competence↗

PubMed2006

Nuclear localization of nuclear factor-kappaB p65 in primary prostate tumors is highly predictive of pelvic lymph node metastases.

PURPOSE: Lymph node invasion (LNI) is associated with increased risk of prostate cancer progression. Unfortunately, pelvic lymph node dissections are fraught with a high rate of false-negative findings, emphasizing the need for highly accurate markers of LNI. Because nuclear factor-kappaB (NF-kappaB) is a candidate marker of prostate cancer progression, we tested the association between nuclear localization of NF-kappaB in radical prostatectomy specimens and the presence of LNI. EXPERIMENTAL DESIGN: NF-kappaB expression in radical prostatectomy specimens was assessed with a monoclonal NF-kappaB p65 antibody, in 20 patients with LNI and in 31 controls with no LNI and no biochemical relapse 5 years after radical prostatectomy. Univariate and multivariate logistic regression models were used. The accuracy of multivariate predictions with and without NF-kappaB was quantified with the area under the receiver operating characteristics curve and 200 bootstrap resamples were used to reduce overfit bias. RESULTS: Univariate regression models showed a 7% increase in the odds of observing LNI for each 1% increase in NF-kappaB nuclear staining (odds ratio, 1.07; P = 0.003). In multivariate models, each 1% increase in NF-kappaB was associated with an 8% increase in the odds of LNI (odds ratio, 1.08; P = 0.03) and its statistical significance was only surpassed by the presence of seminal vesicle invasion (P = 0.003). Addition of NF-kappaB to all other predictors increased the accuracy of LNI prediction by 2.3% (from 84.8% to 87.1%; P < 0.001). CONCLUSION: This is the first study that shows that the extent of nuclear localization of NF-kappaB in primary prostate tumors is highly accurately capable of predicting the probability of locoregional spread of prostate cancer.

Aged↗

PubMed2006

Characteristics and outcomes of patients with carcinoma in situ only at radical cystectomy.

OBJECTIVES: To describe the cancer-specific outcomes of patients with pathologic carcinoma in situ (CIS) only at radical cystectomy. METHODS: The records of 812 consecutive patients who underwent radical cystectomy and pelvic lymphadenectomy for bladder transitional cell carcinoma at three U.S. academic centers were reviewed. Of the 812 patients, 99 (12%) had CIS only at radical cystectomy. RESULTS: The distribution of clinical stage for the 99 patients with CIS only at radical cystectomy was as follows: 47% of patients had CIS only, 8% had cT1, 15% had cT1 plus CIS, 10% had cT2, 13% had cT2 plus CIS, 6% had cTa, and 1% had Ta plus CIS. Two patients had lymphovascular invasion in the radical cystectomy specimen, and three had metastases to the lymph nodes. The actuarial recurrence-free survival estimates were 89.8% (95% confidence interval [CI] 83.0% to 96.6%) at 3 years and 83.0% (95% CI 73.2% to 92.8%) at 5 and 7 years after radical cystectomy. Six patients (6%) had died of bladder cancer at analysis and 13 (13%) had died of other causes without evidence of disease recurrence. The actuarial disease-specific survival estimates were 95.8% (95% CI 91.2% to 99.9%) at 3 years, 90.7% (95% CI 82.4% to 98.9%) at 5 years, and 87.2% (95% CI 76.8% to 97.5%) at 7 years after surgery. On univariate Cox regression analyses, only metastasis to lymph nodes was associated with bladder cancer recurrence and death (P <0.001). CONCLUSIONS: Disease control seemed durable for patients with pathologic CIS only at radical cystectomy in the absence of metastases to the lymph nodes, even in the case of failure after intravesical therapy.

Adult↗

PubMed2006

Concomitant carcinoma in situ is a feature of aggressive disease in patients with organ-confined TCC at radical cystectomy.

OBJECTIVES: Carcinoma in situ (CIS) is a nonpapillary, high-grade, potentially aggressive, and unpredictable manifestation of transitional cell carcinoma (TCC) of the bladder. The aim of this study was to assess whether presence of concomitant CIS has a detrimental effect on cancer control after radical cystectomy. METHODS: The records of 812 consecutive patients who underwent radical cystectomy and pelvic lymphadenectomy for bladder TCC at three US academic centres were reviewed. Ninety-nine of 812 (12%) patients had CIS only at radical cystectomy and were excluded from the analyses. RESULTS: Three hundred thirty of the 713 (46.3%) patients had concomitant CIS at radical cystectomy. Patients with TCC involvement of the urethra were more likely to have concomitant CIS than not (61% vs. 40%, p=0.018). Concomitant CIS was significantly more common in patients with lower cystectomy stages and higher tumour grades. In univariate, but not multivariate, analysis, patients with concomitant CIS versus those without were at increased risk of disease recurrence (p=0.0371). In patients with organ-confined disease, concomitant CIS was an independent predictor of disease recurrence (p=0.048 and p=0.012, respectively) but not bladder cancer-specific mortality (p=0.160 and p=0.408, respectively) after adjusting for the effects of standard postoperative features. CONCLUSIONS: Concomitant CIS in the cystectomy specimen is common, and patients with concomitant CIS are at increased risk of urethral TCC involvement. The presence of concomitant CIS appears to confer a worse prognosis in patients with non-muscle-invasive TCC treated with radical cystectomy.

Adult↗

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

Prostate cancer nomograms: an update.

OBJECTIVE: Several nomograms have been developed to predict outcomes related to prostate cancer (PCa). METHODS: We provide a descriptive and an analytic comparison of nomograms. Further, we report a set of recent PCa nomograms, in which we recorded predictor variables, number of patients used to develop each nomogram, and nomogram-specific features. Moreover, accuracy estimates and type of validation are considered. RESULTS: Our findings suggest a demand for updated nomograms in selected fields of PCa outcomes. Moreover, an increasing number of nomograms address important end points such as prostate-specific antigen recurrence, distant metastases, or androgen-independent PCa-specific survival. CONCLUSION: Our results suggest that nomograms are available for many PCa-related outcomes. They represent a valid methodologic approach if correct criteria are met.

Biopsy↗

PubMed2006

Initial biopsy outcome prediction--head-to-head comparison of a logistic regression-based nomogram versus artificial neural network.

OBJECTIVES: Nomograms and artificial neural networks (ANNs) represent alternative methodologic approaches to predict the probability of prostate cancer on initial biopsy. We hypothesized that, in a head-to-head comparison, one of the approaches might demonstrate better accuracy and performance characteristics than the other. METHODS: A previously published nomogram, which relies on age, digital rectal examination, serum prostate-specific antigen (PSA), and percent-free PSA, and an ANN, which relies on the same predictors plus prostate volume, were applied to a cohort of 3980 men, who were subjected to multicore systematic prostate biopsy. The accuracy and the performance characteristics were compared between these two approaches. RESULTS: The accuracy of the nomogram was 71% versus 67% for the ANN (p=0.0001). Graphical exploration of the performance characteristics demonstrated virtually perfect predictions for the nomogram. Conversely, the ANN underestimated the observed rate of prostate cancer. CONCLUSIONS: A 4% increase in predictive accuracy implies that the use of the nomogram instead of the ANN will result in 40 additional patients who will be correctly classified between benign and cancer.

Adult↗