The role of transrectal ultrasound in diagnosing prostate cancer

Effect of alpha-blocker use on morbidity and lower urinary tract symptoms in patients undergoing transrectal ultrasound-guided prostate biopsy

OBJECTIVE

To evaluate voiding dysfunction and morbidity after transrectal ultrasound (TRUS)-guided prostate biopsy and to investigate whether pre-intervention alpha-blocker treatment had any effect on morbidity and voiding dysfunction.

MATERIAL AND METHODS

The study included 197 consecutive patients who underwent TRUS-guided prostate biopsy between January 2014 and January 2018. The patients were divided into two groups, those receiving alpha-blocker (silodosin) and those not receiving alpha-blocker treatment before the procedure (controls). All patients were evaluated before and one week after the procedure with the International Prostate Symptom Score (IPSS), measurements of maximum flow rate (Q_max), post-void residual urine volume (PVR) and prostate volume, and procedure-related complications were also recorded. All analyzed parameters were compared by within-group and between-group evaluations.

RESULTS

There was no significant difference between the two groups in terms of IPSS, Q_max and prostate volume values before biopsy. In the follow-up evaluation performed on the seventh day after biopsy, IPSS, PVR and prostate volume were found to be increased, whereas Q_max was decreased in the control group (p < 0.05). In the silodosin group, an increase in prostate volume was observed, but there were no significant changes in IPSS, Q_max and PVR values. Acute urinary retention (AUR) after the biopsy procedure developed in two patients (2%) in the silodosin group, and in nine patients (9.1%) in the control group (p = 0.02). No significant difference was found between the two groups in terms of biopsy-related complications, except for AUR.

CONCLUSION

We believe that alpha-blocker treatment initiated before biopsy may be advantageous in preventing voiding dysfunction that may develop after the procedure.

Artificial intelligence in multiparametric prostate cancer imaging with focus on deep-learning methods

Prostate cancer represents today the most typical example of a pathology whose diagnosis requires multiparametric imaging, a strategy where multiple imaging techniques are combined to reach an acceptable diagnostic performance. However, the reviewing, weighing and coupling of multiple images not only places additional burden on the radiologist, it also complicates the reviewing process. Prostate cancer imaging has therefore been an important target for the development of computer-aided diagnostic (CAD) tools. In this survey, we discuss the advances in CAD for prostate cancer over the last decades with special attention to the deep-learning techniques that have been designed in the last few years. Moreover, we elaborate and compare the methods employed to deliver the CAD output to the operator for further medical decision making.

Multiparametric dynamic contrast-enhanced ultrasound imaging of prostate cancer

OBJECTIVES

The aim of this study is to improve the accuracy of dynamic contrast-enhanced ultrasound (DCE-US) for prostate cancer (PCa) localization by means of a multiparametric approach.

MATERIALS AND METHODS

Thirteen different parameters related to either perfusion or dispersion were extracted pixel-by-pixel from 45 DCE-US recordings in 19 patients referred for radical prostatectomy. Multiparametric maps were retrospectively produced using a Gaussian mixture model algorithm. These were subsequently evaluated on their pixel-wise performance in classifying 43 benign and 42 malignant histopathologically confirmed regions of interest, using a prostate-based leave-one-out procedure.

RESULTS

The combination of the spatiotemporal correlation (r), mean transit time (μ), curve skewness (κ), and peak time (PT) yielded an accuracy of 81% ± 11%, which was higher than the best performing single parameters: r (73%), μ (72%), and wash-in time (72%). The negative predictive value increased to 83% ± 16% from 70%, 69% and 67%, respectively. Pixel inclusion based on the confidence level boosted these measures to 90% with half of the pixels excluded, but without disregarding any prostate or region.

CONCLUSIONS

Our results suggest multiparametric DCE-US analysis might be a useful diagnostic tool for PCa, possibly supporting future targeting of biopsies or therapy. Application in other types of cancer can also be foreseen.

KEY POINTS

• DCE-US can be used to extract both perfusion and dispersion-related parameters. • Multiparametric DCE-US performs better in detecting PCa than single-parametric DCE-US. • Multiparametric DCE-US might become a useful tool for PCa localization.

Site of local anaesthesia in transrectal ultrasonography-guided 12-core prostate biopsy: does it make a difference?

OBJECTIVE

To prospectively compare the efficacy of bi-basal vs bi-apical periprostatic nerve block (PPNB) during 12-core prostate biopsy guided by transrectal ultrasonography (TRUS), and to evaluate the pain experienced on inserting the probe compared to the biopsy procedure, as PPNB with lignocaine local anaesthesia has been used for over a decade for minimizing pain during prostatic biopsy.

PATIENTS AND METHODS

In all, 143 men who were to have a TRUS-guided prostate biopsy were systematically randomized to two groups, to receive PPNB at the apex or base. A 10-cm visual analogue score was used to record the pain experienced during probe insertion, the biopsy and just before to leaving the department .

RESULTS

The mean pain score on biopsy in the apical group was similar to that of the basal group (apex 1.9, base 1.6, P = 0.36). Probe introduction produced a significantly higher pain score (probe 2.2, biopsy 1.7, P < 0.001) than at the biopsy.

CONCLUSIONS

Patients who experienced greater pain with the introduction of the probe also reported more pain with the biopsy procedure. The site of local anaesthetic before prostatic biopsy showed no significant difference in pain scores. Older men tolerated the procedure better. Analgesia after PPNB at near either the apex or base appears equal, regardless of the site of injection. We suggest that topical perianal anaesthetic agents could significantly reduce not only pain perception, but also improve tolerance.

Influence of transrectal ultrasound probe on prostate cancer detection in transrectal ultrasound-guided sextant biopsy of prostate

OBJECTIVES

To determine whether end-fire probes increase the prostate cancer (PCa) detection rate. Enhancing the PCa detection rate is the main goal of biopsy protocols. Prostate biopsy is limited by side-fire probes to a longitudinal axis, but end-fire probes allow biopsy cores to also be taken in the transverse section.

METHODS

A total of 2625 patients underwent systematic sextant biopsy in three institutions using the same protocol. Three different ultrasound probes were used-the Kretz Combisone and Bruel & Kjaer side-fire probes and the ATL HDI end-fire probe. We retrospectively evaluated the influence of the probe on the PCa detection rate.

RESULTS

The Kretz probe was used in 384 men, the Bruel & Kjaer probe in 598 men, and the ATL probe in 1643 men. Overall, 35.2% had PCa detected. Analyzing all patients, no statistically significant difference (P = 0.73) was found for the probes, but the subgroup with a prostate-specific antigen level of 4 to 10 ng/mL demonstrated a statistically significant improvement in the detection rate using the end-fire probe (31.3% versus 24.5% and 21.5% for the side-fire probes, P = 0.01). Patients with nonpalpable PCa also demonstrated a statistically significant increase in detection with the end-fire probe (P = 0.004). Multivariate analysis confirmed that the ultrasound probe is an independent parameter to enhance the PCa detection rate.

CONCLUSIONS

Our results showed that end-fire probes provide a statistically significant improvement in the PCa detection rate compared with side-fire probes in patients with a prostate-specific antigen level of 4 to 10 ng/mL and nonpalpable disease. The reason could be the facilitated sampling in the most lateral part of the peripheral zone. Our results suggest that the widespread use of end-fire probes for prostate biopsy could enhance the PCa detection rate.

Effect of peripheral biopsies in maximising early prostate cancer detection in 8-, 10- or 12-core biopsy regimens

OBJECTIVE

To assess the cancer detection rate per individual core biopsy in a 12-core protocol and develop an optimal biopsy regimen for detecting early prostate cancer.

PATIENTS AND METHODS

The study included 445 new patients who had a 12-core transrectal ultrasonography (TRUS)-guided prostatic biopsy over a 40-month period. The 12- core biopsy protocol included parasagittal sextant and six peripheral biopsies. The cancer detection rate per individual core was evaluated to give an optimal biopsy protocol.

RESULTS

Prostate cancer was detected in 142 patients (31.9%). Parasagittal sextant biopsy would have failed to detect 40 (28.2%) of the cancers. Among the various possible biopsy protocols, the optimum 10-core biopsy strategy excluding the parasagittal mid-zone biopsies from the 12-core protocol achieved a cancer detection rate of 98.6%.

CONCLUSION

The cancer detection rate increased from 71.8% for parasagittal sextant biopsies to 88.7% by adding peripheral basal biopsies (8-biopsy protocol); 98.6% of cancers in the series would have been detected with a 10-biopsy strategy omitting the parasagittal mid-zone biopsies. Thus we recommend a 10-core protocol incorporating six peripheral biopsies in patients with elevated age- specific prostate-specific antigen levels (2.6-10.0 ng/mL) for maximising cancer detection.

A risk index for prostate cancer

BACKGROUND

The aim of the present study was to create a simple numerical index predicting the presence of prostate cancer in a group of high risk patients, for the purpose of selecting those most likely to need prostate biopsy.

METHODS

100 consecutive patients at high risk of having prostate cancer seen at Ramathibodi Hospital, Thailand between November 2000 and February 2002 were prospectively studied. All patients underwent transrectal prostate biopsies. The following predictor variables were obtained: age, digital rectal examination (DRE) findings, prostate specific antigen level, transrectal ultrasonography (TRUS) findings, and prostate volume determined by TRUS. The outcome was the presence of prostate cancer on histological examination of the biopsy specimens. A risk index for prostate cancer based on the linear predictor of a multiple logistic regression model was created.

RESULTS

Almost all predictor variables were significantly related to the presence of prostate cancer. The final multiple logistic regression model with four categorized predictors (excluding DRE) was shown to have good discrimination, calibration, and cross-validity. For a cutoff risk index of 10, corresponding to a 10% probability of having prostate cancer, the sensitivity for detecting prostate cancer was 96.2%, with a specificity of 73.0%. Based on this cutoff, 55% of patients in this series might not require prostate biopsy.

CONCLUSION

A risk index for prostate cancer was developed. If this index can be externally validated, the potential savings from avoiding unnecessary prostate biopsies, on the basis of selection using the index, could be significant.