Recursive partitioning for risk stratification in men undergoing repeat prostate biopsies

Presence of Magnetic Resonance Imaging Suspicious Lesion Predicts Gleason 7 or Greater Prostate Cancer in Biopsy-Naive Patients

OBJECTIVE

To compare the relative value of magnetic resonance imaging (MRI) in biopsy-naive patients to those with previous negative biopsy. Although MRI-targeted biopsy has been studied in several major prostate cancer (PCa) cohorts (biopsy naive, previous negative biopsy, and active surveillance), the relative benefit in these cohorts has not been established.

METHODS

We retrospectively reviewed biopsy-naive (n = 45) and previous negative biopsy (n = 55) patients who underwent prostate MRI prior to biopsy at our institution. Patients with an MRI suspicious region (MSR) underwent MRI-targeted biopsy as well as a systematic template biopsy, whereas those without MSR underwent only the template biopsy. All biopsies were performed with the TargetScan (Envisioneering, Pittsburgh, PA) biopsy system. MRI targeting was performed with cognitive guidance.

RESULTS

On multivariate logistic regression, the presence of an MSR was the only statistically significant and independent predictor of Gleason ≥ 7 PCa on biopsy for biopsy-naive men (odds ratio [OR] 40.2, P = .01). For men with previous negative biopsy, the presence of MSR was not a predictor of Gleason ≥ 7 PCa on biopsy (OR 4.35, P = .16), whereas PSA density > 0.15 ng/mL(2) was a significant and independent predictor (OR 66.2, P < .01).

CONCLUSION

Prostate MRI should be considered prior to biopsy in all patients presenting with clinical suspicion for PCa, as presence of a MSR will help guide prebiopsy counseling and provide an opportunity for MRI targeting during biopsy.

Identifying candidates with favorable prognosis following liver transplantation for hepatocellular carcinoma: Data mining analysis

BACKGROUND AND OBJECTIVES

The optimal cutoff of each value in configuring selection criteria for pre-transplant assessment of hepatocellular carcinoma (HCC) remains uncertain.

METHODS

To build a predictive model for recurrent HCC, we performed data mining analysis on patients who underwent LT for HCC at University Health Network (n = 246). The model was externally validated using a cohort from the Scientific Registry of Transplant Recipients (SRTR) database (n = 9,769).

RESULTS

Among 246 patients, 14.6% (n = 36) experienced recurrent HCC within 2.5 years post-LT. The risk prediction model for recurrent HCC identified two subgroups with low-risk (total tumor diameter [TTD] <4 cm and serum alpha-fetoprotein [AFP] <73 ng/ml, n = 135) and with high-risk (TTD >4 cm and/or AFP >73 ng/ml, n = 111). The reproducibility of the model was validated through the SRTR database; overall patient survival rate was significantly better in low-risk group than high-risk group (P < 0.0001). Using Cox regression model, this yardstick, not Milan criteria, was revealed to efficiently predict post-transplant survival independent of underlying characteristics (P < 0.0001).

CONCLUSIONS

Grouping LT candidates with pre-LT HCC by the cutoffs of TTD 4 cm and AFP 73 ng/ml which were unearthed by data mining analysis efficiently classify patients according by the post-transplant prognosis.

Management of men with a suspicion of prostate cancer after negative initial prostate biopsy results

INTRODUCTION

For men with elevated prostate-specific antigen (PSA), appropriate management after negative prostate biopsy remains controversial. After determining PSA kinetics, subsequent follow-up was considered.

PATIENTS AND METHODS

A total of 115 cases with negative repeat biopsy were followed by evaluating PSA kinetics and ratio of percent free PSA (F/T) and by performing second repeat biopsy.

RESULTS

Eighteen cancer cases were diagnosed. Shorter PSA doubling times and faster velocities were found in cancer cases compared with cases without cancer. We observed a clear decrease in F/T among cancer cases.

CONCLUSIONS

To avoid unnecessary repeat biopsies, cases with a suspicion of cancer after negative biopsy can be divided into two groups: one that requires additional biopsies and one with an average change in PSA of <1 ng/ml/year and no change in F/T, which is recommended for surveillance as stable disease without biopsy over a specified time period.

Risk of repeat biopsy and prostate cancer detection after an initial extended negative biopsy: longitudinal follow-up from a prospective trial

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Even after a negative set of prostate biopsies, the risk of undetected prostate cancer remains clinically significant. Predictive markers of such a risk are undefined. In addition to PSA and PSAD, low prostate volume and %fPSA are interesting time-varying risk factors and are relevant in biopsy decision-making.

OBJECTIVE

To assess prospectively the time-varying risk of rebiopsy and of prostate cancer (PCa) detection after an initial negative biopsy protocol.

PATIENTS AND METHODS

Over a period of 10 years, 1995 consecutive patients with initially negative biopsies were followed. Rebiopsies were performed in patients who had a persistent suspicion of PCa. Predictive factors for rebiopsy and for PCa detection were tested using univariate, multivariate and time-dependent models.

RESULTS

A total of 617 men (31%) underwent at least one rebiopsy after a mean follow-up of 19 months. PCa detection rates during second, third, and fourth sets of biopsies were 16.7, 16.9 and 12.5%, respectively. The overall rate of detected PCa was 7.0%. The 5-year rebiopsy-free and PCa-free survival rates were 65.9 and 92.5%, respectively. Indications for rebiopsy were more frequently reported in patients having a high prostate-specific antigen (PSA) level (P = 0.006) or a high PSA density (PSAD; P < 0.001) and in younger patients (P = 0.008). The risk of PCa on rebiopsies was not correlated with age, but significantly increased more than twofold in cases of PSA >6 ng/mL, PSAD >0.15 ng/mL/g, free-to-total PSA ratio (%fPSA) <15, and/or prostate volume <50 mL. Time-dependent analyses were in line with these findings. The main study limitation was the lack of control of the absence of PCa and PSA kinetics in men not rebiopsied.

CONCLUSIONS

The overall risk of detected PCa after an initial negative biopsy was low. In addition to PSA and PSAD, which are well-used in rebiopsy indications, low prostate volume and %fPSA are interesting time-varying risk factors for PCa on rebiopsy and could be relevant in biopsy decision-making.

Model incorporating the ITPA genotype identifies patients at high risk of anemia and treatment failure with pegylated-interferon plus ribavirin therapy for chronic hepatitis C

This study aimed to develop a model for predicting anemia using the inosine triphosphatase (ITPA) genotype and to evaluate its relationship with treatment outcome. Patients with genotype 1b chronic hepatitis C (n = 446) treated with peg-interferon alpha and ribavirin (RBV) for 48 weeks were genotyped for the ITPA (rs1127354) and IL28B (rs8099917) genes. Data mining analysis generated a predictive model for anemia (hemoglobin (Hb) concentration <10 g/dl); the CC genotype of ITPA, baseline Hb <14.0 g/dl, and low creatinine clearance (CLcr) were predictors of anemia. The incidence of anemia was highest in patients with Hb <14.0 g/dl and CLcr <90 ml/min (76%), followed by Hb <14.0 g/dl and ITPA CC (57%). Patients with Hb ≥ 14.0 g/dl and ITPA AA/CA had the lowest incidence of anemia (17%). Patients with two predictors (high-risk) had a higher incidence of anemia than the others (64% vs. 28%, P < 0.0001). At baseline, the IL28B genotype was a predictor of a sustained virological response [adjusted odds ratio 9.88 (95% confidence interval 5.01-19.48), P < 0.0001]. In patients who achieved an early virological response, the IL28B genotype was not associated with a sustained virological response, while a high risk of anemia was a significant negative predictor of a sustained virological response [0.47 (0.24-0.91), P = 0.026]. For high-risk patients with an early virological response, giving >80% of the planned RBV dose increased sustained virological responses by 24%. In conclusion, a predictive model incorporating the ITPA genotype could identify patients with a high risk of anemia and reduced probability of sustained virological response.

Data mining model using simple and readily available factors could identify patients at high risk for hepatocellular carcinoma in chronic hepatitis C

BACKGROUND & AIMS

Assessment of the risk of hepatocellular carcinoma (HCC) development is essential for formulating personalized surveillance or antiviral treatment plan for chronic hepatitis C. We aimed to build a simple model for the identification of patients at high risk of developing HCC.

METHODS

Chronic hepatitis C patients followed for at least 5 years (n=1003) were analyzed by data mining to build a predictive model for HCC development. The model was externally validated using a cohort of 1072 patients (472 with sustained virological response (SVR) and 600 with nonSVR to PEG-interferon plus ribavirin therapy).

RESULTS

On the basis of factors such as age, platelet, albumin, and aspartate aminotransferase, the HCC risk prediction model identified subgroups with high-, intermediate-, and low-risk of HCC with a 5-year HCC development rate of 20.9%, 6.3-7.3%, and 0-1.5%, respectively. The reproducibility of the model was confirmed through external validation (r(2)=0.981). The 10-year HCC development rate was also significantly higher in the high-and intermediate-risk group than in the low-risk group (24.5% vs. 4.8%; p<0.0001). In the high-and intermediate-risk group, the incidence of HCC development was significantly reduced in patients with SVR compared to those with nonSVR (5-year rate, 9.5% vs. 4.5%; p=0.040).

CONCLUSIONS

The HCC risk prediction model uses simple and readily available factors and identifies patients at a high risk of HCC development. The model allows physicians to identify patients requiring HCC surveillance and those who benefit from IFN therapy to prevent HCC.

Prostate cancer detection after a negative prostate biopsy: lessons learnt in the Cleveland Clinic experience

Urologists are often faced with the dilemma of managing patients with a negative initial prostate biopsy in whom clinical or pathological risk for prostate cancer still exists. Such real-life challenging scenarios might raise questions such as: Who should undergo further biopsies? What are the optimal predictors for prostate cancer on subsequent biopsies? What is the optimal biopsy protocol that should be used? When to stop the biopsy cascade? The last decade has witnessed numerous studies that have analyzed factors conferring a significant risk for cancer discovered on repeat biopsies. We and others have developed predictive models to aid decision-making regarding pursuing further biopsies. For decades, high-grade prostatic intraepithelial neoplasia has been considered a strong risk indicator for subsequent cancer. However, it has been recently shown that only through segmentation of this heterogeneous population does the real risk profile emerge. Biopsy templates underwent modification regarding the number and location of cores with emergence of the transrectal or brachytherapy grid transperineal saturation biopsy. However, the best biopsy protocol remains controversial. We have refined the initial biopsy template to a 14 core initial biopsy template that optimizes cancer detection, and have shown that transrectal saturation biopsy significantly improves cancer detection for repeat biopsy. Another concern is the overdiagnosis of clinically insignificant cancer on repeat biopsies, so we explored ways to limit this, and to deal with its ramifications. Through carrying out a Medline literature search, we critically evaluated pertinent articles together with emphasis of our own journey in this arena to assist in the decision-making process for repeat biopsy population.

A novel repeat biopsy nomogram based on three-dimensional extended biopsy

OBJECTIVES

To develop a nomogram based on a cohort examined with 3-dimensional (3D) protocol for diagnosis of prostate cancer on repeat biopsy.

METHODS

Of 4074 consecutive men undergoing prostate biopsy at our institutions between 2000 and 2009, 775 men with at least 1 previous negative biopsy underwent repeat biopsy with a 3D protocol. Men with previous atypical glands or atypical small acinar proliferation and/or without available prostate-specific antigen (PSA) kinetics information were excluded. The remaining 515 men constituted the study cohort. We developed a logistic regression-based nomogram with 70% of the cohort selected randomly; we validated it with the remaining 30%. Predictive accuracy and performance characteristics were assessed using the area under the receiver operating characteristic curve (AUC) and calibration plots, respectively. The threshold probability was evaluated with decision curve analysis.

RESULTS

We developed a novel repeat biopsy nomogram incorporating age, free to total PSA ratio, prostate volume, history of previous extended biopsy, and PSA doubling time. Validation confirmed predictive accuracy with an AUC value of 0.791. Calibration plots showed good agreement. The decision curve of the nomogram was superior to the decision curve of biopsying all men in a range of threshold probability over 0.15. At the threshold of 0.2, the number of unnecessary biopsies could be reduced by 10 per 100, without missing prostate cancer.

CONCLUSIONS

We developed a novel repeat biopsy nomogram based on a cohort examined with 3D protocol. This repeat biopsy nomogram is clinically beneficial, preventing a substantial number of unnecessary biopsies.

Risk factors for prostate cancer detection after a negative biopsy: a novel multivariable longitudinal approach

PURPOSE

To introduce a novel approach for the time-dependent quantification of risk factors for prostate cancer (PCa) detection after an initial negative biopsy.

PATIENTS AND METHODS

Data for 1,871 men with initial negative biopsies and at least one follow-up biopsy were available. Piecewise exponential regression models were developed to quantify hazard ratios (HRs) and define cumulative incidence curves for PCa detection for subgroups with specific patterns of risk factors over time. Factors evaluated included age, race, serum prostate-specific antigen (PSA) concentration, PSA slope, digital rectal examination, dysplastic glands or prostatitis on biopsy, ultrasound gland volume, urinary symptoms, and number of negative biopsies.

RESULTS

Four hundred sixty-five men had PCa detected, after a mean follow-up time of 2.8 years. All of the factors were independent predictors of PCa detection except for PSA slope, as a result of its correlation with time-dependent PSA level, and race. PSA (HR = 3.90 for > 10 v 2.5 to 3.9 ng/mL), high-grade prostatic intraepithelial neoplasia/atypical glands (HR = 2.97), gland volume (HR = 0.39 for > 50 v < 25 mL), and number of repeat biopsies (HR = 0.36 for two v zero repeat biopsies) were the strongest predictors. Men with high-risk versus low-risk event histories had a 20-fold difference in PCa detection over 5 years.

CONCLUSION

Piecewise exponential models provide an approach to longitudinal analysis of PCa risk that allows clinicians to see the interplay of risk factors as they unfold over time for individual patients. With these models, it is possible to identify distinct subpopulations with dramatically different needs for monitoring and repeat biopsy.

Current applications for prostate-specific antigen doubling time

OBJECTIVE

To review the current status of prostate-specific antigen doubling time (PSADT) as it pertains to the evolution of prostate cancer (PCa), specifically assessing its role in the following four stages: before diagnosis, prior to definitive treatment, following treatment including salvage therapy after recurrence, and lastly, after onset of androgen-insensitive PCa.

METHODS

We searched PubMed literature for current articles on PSADT using the key words listed for this review and, where possible, selected those with significant levels of evidence that were deemed relevant, seminal, or controversial. We summarized the data regarding PSADT as a marker for diagnosis and disease characterization, as well as a predictor of progression, response to treatment, and mortality.

RESULTS

PSADT may offer an advantage in providing a more dynamic picture of tumor behavior, providing clues regarding the relative aggressiveness of the underlying pathology. Evidence points toward a role for PSADT in the management of PCa, specifically in active surveillance, disease recurrence after treatment, and in androgen-independent PCa. PSADT is an important prognostic factor that may serve as an auxiliary end point for cancer-specific survival; however, optimal cut-off points denoting risk remain debatable.

CONCLUSIONS

PCa management requires risk stratification with a combination of variables, PSADT being one of the most reliable predictors. It is now a parameter included in many predictive nomograms and in treatment guidelines for expectant management and salvage therapy.

Prostate-specific antigen velocity in untreated, localized prostate cancer

OBJECTIVE

To report the results of a prospective study of active surveillance of untreated prostate cancer, with a focus on baseline predictors of prostate-specific antigen (PSA) velocity, as PSA velocity before treatment is an important predictor of prostate cancer mortality, and patients on active surveillance are monitored for several years to estimate the PSA velocity and thus select patients for radical treatment.

PATIENTS AND METHODS

A prospective study of active surveillance for localized prostate cancer opened at the Royal Marsden Hospital in 2002. Eligible patients had clinical stage T1/T2a, N0/Nx, M0/Mx adenocarcinoma of the prostate with a serum PSA level of < 15 ng/mL, a Gleason score of < or = 7 with primary grade < or = 3, and less than half the biopsy cores positive. The PSA velocity before treatment was analysed in relation to baseline clinical characteristics.

RESULTS

In all, 237 patients on surveillance were followed for a median of 24 months (median age 67 years; median initial PSA level 6.5 ng/mL; median pretreatment PSA velocity 0.44 ng/mL per year). On multivariate analysis, PSA density (i.e. serum PSA level/prostate volume) was the only significant determinant of PSA velocity (P < 0.001). Patients with a PSA density above or below the median (0.185 ng/mL/mL) had a median (interquartile range) PSA velocity of 0.92 (0.34-1.77) ng/mL per year and 0.35 (-0.06, 0.80) ng/mL per year, respectively.

CONCLUSIONS

PSA density, which is readily available at the time of diagnosis, is an independent determinant of PSA velocity in untreated, localized prostate cancer. If this is confirmed, PSA density could be used to inform the often difficult choice between active surveillance and immediate radical treatment.

Nanomedicine and drug delivery

This article discusses the use of nanotechnology in drug delivery approaches. Magnetic nanotechnology is finding wide applications in medicine, most notably in MRI and magnetic separation. The impedance biosensor is expected to find applications in monitoring cytokines in cancer, bone turnover markers in osteoporosis, and understanding neural-degenerative diseases.

Diagnosis of prostate cancer

The contemporary challenge of prostate cancer diagnosis has been changed in the past decade from the endeavor to increase detection to that of detecting only those tumors that are clinically significant. Better interpretation of the role of prostate-specific antigen (PSA) and its kinetics as a diagnostic tool, the adoption of extended prostate biopsy schemes, and perhaps implementation of new transrectal ultrasound (TRUS) technologies promote the achievement of this clinical mission. This chapter reviews these issues as well as the change in practice of patient preparation for TRUS-biopsy and analgesia during it, the role of repeat and saturation prostate biopsies, and the interpretation of an incidental prostate cancer finding. Currently, the lifetime risk of a diagnosis of prostate cancer for North American men is 16%, compared to the lifetime risk of death from prostate cancer, which is 3% (Carter 2004). The advent of prostate-specific antigen (PSA) screening and transrectal ultrasonography (TRUS) has significantly impacted the detection of prostate cancer over the last 20 years. The mean age at diagnosis has decreased (Hankey et al. 1999; Stamey et al. 2004) and the most common stage at diagnosis is now localized disease (Newcomer et al. 1997; Stamey et al. 2004). The goal of prostate cancer screening is to detect only those men at risk for death from the disease at an early curable phase. The ambiguous natural history of this most common malignancy in men, being latent with questionable life-threatening potential in a large number of cases on the one hand, with only a relatively small number (though not negligible) of highly malignant cases on the other, propels many doubts about whether this is possible. This was famously phrased more than 20 years ago by Whitmore who asked: "Is cure possible for those in whom it is necessary; and is it necessary for those in whom it is possible?" This is probably even more relevant nowadays. During the past decade two factors influenced significantly the increased detection rate of prostate cancer in general and that of clinically insignificant prostate cancers in particular: the widespread use of serum PSA as a screening tool to a large extent and to a lesser though significant extent the application of extended multiple core biopsy schemes (Master et al. 2005). In fact, 75% of men in the United States aged 50 years and older have been screened with the PSA test (Sirovich et al. 2003). Outside of the screening context, which is dealt with in depth in Chap. 5, clinical suspicion of prostate cancer is raised usually by abnormal digital rectal examination (DRE) and/or by abnormal levels of serum PSA. Final diagnosis is achieved only based on positive prostate biopsies.

Repeat prostate biopsy in the Prostate, Lung, Colorectal and Ovarian cancer screening trial

OBJECTIVE

To determine patterns of repeat prostate biopsy in a cohort of men undergoing prostate cancer screening who have a negative initial biopsy.

SUBJECTS AND METHODS

The Prostate, Colorectal, Lung, and Ovarian (PLCO) cancer screening trial is an ongoing study the prostate component of which consists of six annual screens with measurements of prostate-specific antigen (PSA) level and a digital rectal examination (DRE). The diagnostic follow-up of positive screening results is done by the subject's healthcare provider outside the purview of the PLCO. We analysed the experience of repeat biopsy in men in the PLCO with an initial negative biopsy. Men were divided by indication for initial biopsy into those with suspicious PSA levels and those with suspicious DRE findings.

RESULTS

The probability of having a repeat biopsy within 3 years of initial biopsy was 43% for 1736 men with suspicious PSA levels and 13% for 1025 men with suspicious DRE findings. Rates of third and fourth biopsy after a previous negative biopsy were similar to the initial repeat biopsy rate in PSA-positive men. Most men had a repeat biopsy only after having an additional round of screening. The PSA level and PSA velocity determined after initial biopsy were independent risk factors for a repeat biopsy, both in PSA-positive and DRE-positive men. High-grade prostatic intraepithelial neoplasia was a risk factor for repeat biopsy before any repeat PSA or DRE testing.

CONCLUSION

The experience of this cohort should be generally representative of patterns of care for repeat biopsy in men undergoing periodic screening. These data can provide context to the debate over optimum practices for repeat biopsy.