Prostate cancer imaging: what the urologist wants to know

Clinical application of machine learning models in patients with prostate cancer before prostatectomy

BACKGROUND

To build machine learning predictive models for surgical risk assessment of extracapsular extension (ECE) in patients with prostate cancer (PCa) before radical prostatectomy; and to compare the use of decision curve analysis (DCA) and receiver operating characteristic (ROC) metrics for selecting input feature combinations in models.

METHODS

This retrospective observational study included two independent data sets: 139 participants from a single institution (training), and 55 from 15 other institutions (external validation), both treated with Robotic Assisted Radical Prostatectomy (RARP). Five ML models, based on different combinations of clinical, semantic (interpreted by a radiologist) and radiomics features computed from T2W-MRI images, were built to predict extracapsular extension in the prostatectomy specimen (pECE+). DCA plots were used to rank the models' net benefit when assigning patients to prostatectomy with non-nerve-sparing surgery (NNSS) or nerve-sparing surgery (NSS), depending on the predicted ECE status. DCA model rankings were compared with those drived from ROC area under the curve (AUC).

RESULTS

In the training data, the model using clinical, semantic, and radiomics features gave the highest net benefit values across relevant threshold probabilities, and similar decision curve was observed in the external validation data. The model ranking using the AUC was different in the discovery group and favoured the model using clinical + semantic features only.

CONCLUSIONS

The combined model based on clinical, semantic and radiomic features may be used to predict pECE + in patients with PCa and results in a positive net benefit when used to choose between prostatectomy with NNS or NNSS.

Early biomarkers of extracapsular extension of prostate cancer using MRI-derived semantic features

BACKGROUND

To construct a model based on magnetic resonance imaging (MRI) features and histological and clinical variables for the prediction of pathology-detected extracapsular extension (pECE) in patients with prostate cancer (PCa).

METHODS

We performed a prospective 3 T MRI study comparing the clinical and MRI data on pECE obtained from patients treated using robotic-assisted radical prostatectomy (RARP) at our institution. The covariates under consideration were prostate-specific antigen (PSA) levels, the patient's age, prostate volume, and MRI interpretative features for predicting pECE based on the Prostate Imaging-Reporting and Data System (PI-RADS) version 2.0 (v2), as well as tumor capsular contact length (TCCL), length of the index lesion, and prostate biopsy Gleason score (GS). Univariable and multivariable logistic regression models were applied to explore the statistical associations and construct the model. We also recruited an additional set of participants-which included 59 patients from external institutions-to validate the model.

RESULTS

The study participants included 184 patients who had undergone RARP at our institution, 26% of whom were pECE+ (i.e., pECE positive). Significant predictors of pECE+ were TCCL, capsular disruption, measurable ECE on MRI, and a GS of ≥7(4 + 3) on a prostate biopsy. The strongest predictor of pECE+ is measurable ECE on MRI, and in its absence, a combination of TCCL and prostate biopsy GS was significantly effective for detecting the patient's risk of being pECE+. Our predictive model showed a satisfactory performance at distinguishing between patients with pECE+ and patients with pECE-, with an area under the ROC curve (AUC) of 0.90 (86.0-95.8%), high sensitivity (86%), and moderate specificity (70%).

CONCLUSIONS

Our predictive model, based on consistent MRI features (i.e., measurable ECE and TCCL) and a prostate biopsy GS, has satisfactory performance and sufficiently high sensitivity for predicting pECE+. Hence, the model could be a valuable tool for surgeons planning preoperative nerve sparing, as it would reduce positive surgical margins.

Propionic Acid-Based PET Imaging of Prostate Cancer

PURPOSE

This study aimed to evaluate the potential value of 2-[¹⁸F]fluoropropionic acid ([¹⁸F]FPA) for PET imaging of prostate cancer (PCa) and to explore the relationship between [¹⁸F]FPA accumulation and fatty acid synthase (FASN) levels in PCa models. The results of the first [¹⁸F]FPA PET study of a PCa patient are reported.

PROCEDURES

The LNCaP, PC-3 cell lines with high FASN expression, and DU145 cell lines with low FASN expression were selected for cell culture. A PET imaging comparison of [¹⁸F]FDG and [¹⁸F]FPA was performed in LNCaP, PC-3, and DU145 tumors. Additionally, in vivo inhibition experiments in those models were conducted with orlistat. In a human PET study, a patient with PCa before surgery was examined with [¹⁸F]FPA PET and [¹⁸F]FDG PET.

RESULTS

The uptake of [¹⁸F]FPA in the LNCaP and PC-3 tumors was higher than that of [¹⁸F]FDG (P<0.05 and P<0.05), but was lower in DU145 tumors (P<0.05). The accumulation (% ID/g) of [¹⁸F]FPA in the LNCaP, PC-3, and DU145 tumors decreased by 27.6, 40.5, and 11.7 %, respectively, after treatment with orlistat. The [¹⁸F]FPA showed higher radioactive uptake than [¹⁸F]FDG in the first PCa patient.

CONCLUSIONS

The [¹⁸F]FPA uptake in PCa models may be varies with fatty acid synthase activity and could be reduced after administration of a single FASN inhibitor, albeit the activity that is not measured directly. The [¹⁸F]FPA seems to be a potential broad-spectrum PET imaging agent and may serve as a valuable tool in the diagnosis of PCa in humans.

PET/MRI: The future of cancer restaging

The re-staging of cancer is one of the main oncological problems faced in the present day. Restaging can lead to the emergence of surgical therapy alternatives for a down-staged cancer, or to the consideration of secondary or tertiary chemotherapies for an up-staged cancer. That said, with the application of one of the surgical, radiotheraphy(RT) or chemotherapy(CT) protocols, complications may occur, and restaging becomes difficult. Another difficulty may be encountered in explaining to the patient that additional therapy protocols may be needed after an accurate restaging. After surgery, RT or CT, renal, hepatic and bone marrow reserves may severely be decreased, and since the primary therapy protocol may reduce significantly the patient's performance status, "accurate restaging" is the most important problem to be resolved when planning further therapy.

Limitations of abdominopelvic CT and multiparametric MR imaging for detection of lymph node metastases prior to radical prostatectomy

PURPOSE

To investigate the performance of pre-surgery CT and multiparametric MRI (mpMRI) to identify lymph node (LN) metastases in the Michigan Urological Surgery Improvement Collaborative (MUSIC). Abdominopelvic CT and mpMRI are commonly used for intermediate- and high-risk prostate cancer (PCa) staging.

METHODS

Retrospective analysis of the MUSIC registry identified patients undergoing robot-assisted radical prostatectomy (RP) between 3/2012 and 7/2018. Patients were classified according to pre-surgery imaging modality. Primary outcomes were operating characteristics of CT and mpMRI for detection of pathologic LN involvement (pN1).

RESULTS

A total of 10,250 patients underwent RP and 3924 patients (38.3%) underwent CT and/or mpMRI prior to surgery. Suspicion for LN involvement was identified on 2.3% CT and 1.9% mpMRI. Overall, 391 patients were pN1(3.8%), including 0.1% low-, 2.1% intermediate-, and 10.9% high-risk PCa patients. Of 235 pN1 patients that underwent CT prior, far more had negative (91.1%) than positive (8.9%) findings, yielding sensitivity: 8.9%, specificity: 98.3%, negative predictive value (NPV): 92.1%, and positive predictive value (PPV): 32.3% for CT with regard to LN metastases. Similarly, more patients with pN1 disease had negative mpMRI (81.0%) then suspicious or indeterminate MRI (19.0%), yielding sensitivity: 19.0%, specificity: 97.3%, NPV: 95.9%, and PPV: 26.7%.

CONCLUSIONS

Abdominopelvic CT and mpMRI have clear limitations in identifying LN metastases. Additional clinicopathologic features should be considered when making management decisions, as 2.1% and 10.9% with intermediate-and high-risk cancer had metastatic LNs. The majority of pN1 patients had a negative CT or a negative/indeterminate mpMRI prior to RP. Pelvic LN dissection should be performed in RP patients with intermediate- or high-risk PCa, independent of preoperative imaging results.

Localising occult prostate cancer metastasis with advanced imaging techniques (LOCATE trial): a prospective cohort, observational diagnostic accuracy trial investigating whole-body magnetic resonance imaging in radio-recurrent prostate cancer

BACKGROUND

Accurate whole-body staging following biochemical relapse in prostate cancer is vital in determining the optimum disease management. Current imaging guidelines recommend various imaging platforms such as computed tomography (CT), Technetium 99 m (99mTc) bone scan and 18F-choline and recently 68Ga-PSMA positron emission tomography (PET) for the evaluation of the extent of disease. Such approach requires multiple hospital attendances and can be time and resource intensive. Recently, whole-body magnetic resonance imaging (WB-MRI) has been used in a single visit scanning session for several malignancies, including prostate cancer, with promising results, providing similar accuracy compared to the combined conventional imaging techniques. The LOCATE trial aims to investigate the application of WB-MRI for re-staging of patients with biochemical relapse (BCR) following external beam radiotherapy and brachytherapy in patients with prostate cancer.

METHODS/DESIGN

The LOCATE trial is a prospective cohort, multi-centre, non-randomised, diagnostic accuracy study comparing WB-MRI and conventional imaging. Eligible patients will undergo WB-MRI in addition to conventional imaging investigations at the time of BCR and will be asked to attend a second WB-MRI exam, 12-months following the initial scan. WB-MRI results will be compared to an enhanced reference standard comprising all the initial, follow-up imaging and non-imaging investigations. The diagnostic performance (sensitivity and specificity analysis) of WB-MRI for re-staging of BCR will be investigated against the enhanced reference standard on a per-patient basis. An economic analysis of WB-MRI compared to conventional imaging pathways will be performed to inform the cost-effectiveness of the WB-MRI imaging pathway. Additionally, an exploratory sub-study will be performed on blood samples and exosome-derived human epidermal growth factor receptor (HER) dimer measurements will be taken to investigate its significance in this cohort.

DISCUSSION

The LOCATE trial will compare WB-MRI versus the conventional imaging pathway including its cost-effectiveness, therefore informing the most accurate and efficient imaging pathway.

TRIAL REGISTRATION

LOCATE trial was registered on ClinicalTrial.gov on 18th of October 2016 with registration reference number NCT02935816.

Modern imaging and image-guided treatments of the prostate gland: MR and ablation for cancer and prostatic artery embolization for benign prostatic hyperplasia

Multiparametric MRI (mpMRI) has proven to be an essential tool for diagnosis, post-treatment follow-up, aggressiveness assessment, and active surveillance of prostate cancer. Currently, this imaging technique is part of the daily practice in many oncological centres. This manuscript aims to review the use of mpMRI in the set of prostatic diseases, either malignant or benign: mpMRI to detect and stage prostate cancer is discussed, as well as its use for active surveillance. Image-guided ablation techniques for prostate cancer are also reviewed. The need to establish minimum acceptable technical parameters for prostate mpMRI, standardize reports, uniform terminology for describing imaging findings, and develop assessment categories that differentiate levels of suspicion for clinically significant prostate cancer led to the development of the Prostate Imaging Reporting and Data System that is reviewed. Special focus will also be given on the most up-to-date evidence of prostatic artery embolization (PAE) for symptomatic benign prostatic hyperplasia (BPH). Management of patients with BPH, technical aspects of PAE, expected outcomes and level of evidence are reviewed with the most recent literature. PAE is a challenging technique that requires dedicated anatomical knowledge and comprehensive embolization skills. PAE has been shown to be an effective minimally-invasive treatment option for symptomatic BPH patients, that can be viewed between medical therapy and surgery. PAE may be a good option for symptomatic BPH patients that do not want to be operated and can obviate the need for prostatic surgery in up to 80% of treated patients.

Thoracic Manifestations of Genitourinary Neoplasms and Treatment-related Complications

Genitourinary (GU) malignancies are a diverse group of common and uncommon neoplasms that may be associated with significant mortality. Metastases from GU neoplasms are frequently encountered in the chest, and virtually all thoracic structures can be involved. Although the most common imaging manifestations include hematogenous dissemination manifesting with peripheral predominant bilateral pulmonary nodules and lymphatic metastases manifesting with mediastinal and hilar lymphadenopathy, some GU malignancies exhibit unique features. We review the general patterns, pathways, and thoracic imaging features of renal, adrenal, urothelial, prostatic, and testicular metastatic neoplasms, as well as provide a discussion of treatment-related complications that might manifest in the chest. Detailed reporting of these patterns will allow the imager to assist the referring clinicians and surgeons in accurate determination of the stage, prognosis, and treatment options available for the patient. Awareness of specific treatment-related complications further allows the imager to enhance patient safety through accurate and timely reporting of potentially life-threatening consequences of therapies.

Advances in prostate cancer imaging

Many exciting advances in medical imaging have been made in recent years that will alter the way we diagnose, stage, and treat patients with prostate cancer. Multiparametric magnetic resonance imaging (MRI) is emerging as the main modality for prostate cancer imaging. Contrast-enhanced ultrasound and shear wave elastography may be strong alternatives in patients who cannot undergo MRI. Prostate-specific membrane antigen-directed positron emission tomography/computed tomography has proven to be valuable in the primary staging of high-risk disease and for detecting disease in patients with biochemical recurrence. As more studies continue to emerge, it is becoming clear that the standard algorithm for diagnosing and staging prostate cancer will undergo significant changes in the near future.

The Role of Imaging in Prostate Cancer Care Pathway: Novel Approaches to Urologic Management Challenges Along 10 Imaging Touch Points

We map out a typical prostate cancer care pathway through discussion of updates on modern imaging. Multiparametric magnetic resonance imaging is the most sensitive and specific imaging tool for diagnosis and local staging, but transrectal ultrasound remains the most widely used technique for prostate biopsy guidance. Computed tomography and bone scan are useful in initial staging and recurrence detection. Novel imaging techniques in ultrasound elastography and multiparametric magnetic resonance imaging allow for increased lesion detection sensitivity and have the potential to enhance biopsy, while the development of new positron emission tomography radiotracers has great promise for improved detection of local and metastatic disease in patients with biochemical recurrence.

EpCAM Expression in Lymph Node and Bone Metastases of Prostate Carcinoma: A Pilot Study

There is an urgent need for new imaging modalities in prostate carcinoma staging. A non-invasive modality that can assess lymph node and bone metastases simultaneously is preferred. Epithelial cell adhesion molecule (EpCAM) is a membranous protein of interest as an imaging target since it is overexpressed in prostatic carcinoma compared with benign prostate epithelium and compared with stroma. However, EpCAM expression in lymph node metastases is sparsely available in the literature and EpCAM expression in bone metastases is yet unknown. The current study evaluates the expression of EpCAM in prostate carcinoma lymph nodes, in matched normal lymph nodes, in prostate carcinoma bone metastases, and in normal bone by immunohistochemistry. EpCAM was expressed in 100% of lymph node metastases (21 out of 21), in 0% of normal lymph nodes (0 out of 21), in 95% of bone metastases (19 out of 20), and in 0% of normal bone (0 out of 14). Based on these results, EpCAM may be a feasible imaging target in prostate carcinoma lymph node and bone metastases. Prospective clinical trials are needed to confirm current results. Preoperative visualization of prostate carcinoma metastases will improve disease staging and will prevent unnecessary invasive surgery.

Recurrent prostate cancer detection with anti-3-[(18)F]FACBC PET/CT: comparison with CT

PURPOSE

To compare the diagnostic performance of the synthetic amino acid analogue PET radiotracer anti-3-[(18)F]FACBC (fluciclovine) with that of CT in the detection of recurrent prostate carcinoma.

METHODS

This was a retrospective analysis of 53 bone scan-negative patients with suspected recurrent prostate carcinoma who underwent fluciclovine PET/CT and routine clinical CT within 90 days of each other. The correlation between imaging findings and histology and clinical follow-up was evaluated. Positivity rates and diagnostic performance were calculated for fluciclovine PET/CT and CT.

RESULTS

Of 53 fluciclovine PET/CT and 53 CT examinations, 41 (77.4 %) and 10 (18.9 %), respectively, had positive findings for recurrent disease. Positivity rates were higher with fluciclovine PET/CT than with CT at all prostate-specific antigen (PSA) levels, PSA doubling times and original Gleason scores. In the prostate/bed, fluciclovine PET/CT was true-positive in 31 and CT was true-positive in 4 of 51 patients who met the reference standard. In extraprostatic regions, fluciclovine PET/CT was true-positive in 12 and CT was true-positive in 3 of 41 patients who met the reference standard. Of the 43 index lesions used to prove positivity, 42 (97.7 %) had histological proof. In 51 patients with sufficient follow-up to calculate diagnostic performance in the prostate/bed, fluciclovine PET/CT demonstrated a sensitivity of 88.6 %, a specificity of 56.3 %, an accuracy of 78.4 %, a positive predictive value (PPV) of 81.6 %, and a negative predictive value (NPV) of 69.2 %; the respective values for CT were 11.4 %, 87.5 %, 35.3 %, 66.7 % and 31.1 %. In 41 patients with sufficient follow-up to calculate diagnostic performance in extraprostatic regions, fluciclovine PET/CT demonstrated a sensitivity of 46.2 %, a specificity of 100 %, an accuracy of 65.9 %, a PPV of 100 %, and an NPV of 51.7 %; the respective values for CT were 11.5 %, 100 %, 43.9 %, 100 % and 39.5 %.

CONCLUSION

The diagnostic performance of fluciclovine PET/CT in recurrent prostate cancer is superior to that of CT and fluciclovine PET/CT provides better delineation of prostatic from extraprostatic recurrence.

Multiparametric ultrasound in the detection of prostate cancer: a systematic review

PURPOSE

To investigate the advances and clinical results of the different ultrasound modalities and the progress in combining them into multiparametric UltraSound (mpUS).

METHODS

A systematic literature search on mpUS and the different ultrasound modalities included: greyscale ultrasound, computerized transrectal ultrasound, Doppler and power Doppler techniques, dynamic contrast-enhanced ultrasound and (shear wave) elastography.

RESULTS

Limited research available on combining ultrasound modalities has presented improvement in diagnostic performance. The data of two studies suggest that even adding a lower performing ultrasound modality to a better performing modality using crude methods can already improve the sensitivity by 13-51 %. The different modalities detect different tumours. No study has tried to combine ultrasound modalities employing a system similar to the PIRADS system used for mpMRI or more advanced classifying algorithms.

CONCLUSION

Available evidence confirms that combining different ultrasound modalities significantly improves diagnostic performance.

Preclinical comparison of Al18F- and 68Ga-labeled gastrin-releasing peptide receptor antagonists for PET imaging of prostate cancer

Gastrin-releasing peptide receptor (GRPR) is overexpressed in human prostate cancer and is being used as a target for molecular imaging. In this study, we report on the direct comparison of 3 novel GRPR-targeted radiolabeled tracers: Al(18)F-JMV5132, (68)Ga-JMV5132, and (68)Ga-JMV4168 (JMV5132 is NODA-MPAA-βAla-βAla-[H-D-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2], JMV4168 is DOTA-βAla-βAla-[H-D-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2], and NODA-MPAA is 2-[4-(carboxymethyl)-7-{[4-(carboxymethyl)phenyl]methyl}-1,4,7-triazacyclononan-1-yl]acetic acid).

METHODS

The GRPR antagonist JMV594 (H-D-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2) was conjugated to NODA-MPAA for labeling with Al(18)F. JMV5132 was radiolabeled with (68)Ga and (18)F, and JMV4168 was labeled with (68)Ga for comparison. The inhibitory concentration of 50% values for binding GRPR of JMV4168, JMV5132, (nat)Ga-JMV4168, and (nat)Ga-JMV5132 were determined in a competition-binding assay using GRPR-overexpressing PC-3 tumors. The tumor-targeting characteristics of the compounds were assessed in mice bearing subcutaneous PC-3 xenografts. Small-animal PET/CT images were acquired, and tracer biodistribution was determined by ex vivo measurements.

RESULTS

JMV5132 was labeled with (18)F in a novel 1-pot, 1-step procedure within 20 min, without need for further purification and resulting in a specific activity of 35 MBq/nmol. Inhibitory concentration of 50% values (in nM) for GRPR binding of JMV5132, JMV4168, (nat)Ga-JMV5132, (nat)Ga-JMV4168, and Al(nat)F-JMV5132 were 6.8 (95% confidence intervals [CIs], 4.6-10.0), 13.2 (95% CIs, 5.9-29.3), 3.0 (95% CIs, 1.5-6.0), 3.2 (95% CIs, 1.8-5.9), and 10.0 (95% CIs, 6.3-16.0), respectively. In mice with subcutaneous PC-3 xenografts, all tracers cleared rapidly from the blood, exclusively via the kidneys for (68)Ga-JMV4168 and partially hepatobiliary for (68)Ga-JMV5132 and Al(18)F-JMV5132. Two hours after injection, the uptake of (68)Ga-JMV4168, (68)Ga-JMV5132, and Al(18)F-JMV5132 in PC-3 tumors was 5.96 ± 1.39, 5.24 ± 0.29, 5.30 ± 0.98 (percentage injected dose per gram), respectively. GRPR specificity was confirmed by significantly reduced tumor uptake of the 3 tracers after coinjection of a 100-fold excess of unlabeled JMV4168 or JMV5132. Small-animal PET/CT clearly visualized PC-3 tumors, with the highest resolution observed for Al(18)F-JMV5132.

CONCLUSION

JMV5132 could be rapidly and efficiently labeled with (18)F. Al(18)F-JMV5132, (68)Ga-JMV5132, and (68)Ga-JMV4168 all showed comparable high and specific accumulation in GRPR-positive PC-3 tumors. These new PET tracers are promising candidates for future clinical translation.

Multiparametric MRI in prostate cancer management

Prostate cancer is the second most common cancer in men worldwide. The clinical behaviour of prostate cancer ranges from low-grade indolent tumours that never develop into clinically significant disease to aggressive, invasive tumours that may progress rapidly to metastatic disease and death. Therefore, there is an urgent clinical need to detect high-grade cancers and to differentiate them from the indolent, slow-growing tumours. Conventional methods of cancer detection-such as levels of prostate-specific antigen (PSA) in serum, digital rectal examination, and random biopsies-are limited in their sensitivity, specificity, or both. The combination of conventional anatomical MRI and functional magnet resonance sequences-known as multiparametric MRI (mp-MRI)-is emerging as an accurate tool for identifying clinically relevant tumours owing to its ability to localize them. In this Review, we discuss the value of mp-MRI in localized and metastatic prostate cancer, highlighting its role in the detection, staging, and treatment planning of prostate cancer.

Magnetic resonance imaging of pelvic metastases in male patients

Magnetic resonance (MR) imaging offers a noninvasive tool for diagnosis of primary and metastatic pelvic tumors. The diagnosis of a pelvic metastatic lesion implies an adverse prognosis and dictates the management strategies. Knowledge of normal MR imaging anatomy of the pelvis and the signal characteristics of normal and abnormal structures is essential for accurate interpretation of pelvic MR imaging. This article reviews imaging manifestations of nodal, visceral, and musculoskeletal metastatic lesions of the pelvis along with current and evolving MR imaging techniques.

Improving the biodistribution of PSMA-targeting tracers with a highly negatively charged linker

BACKGROUND

Prostate specific membrane antigen (PSMA) is overexpressed in prostate cancer and in tumor vasculature. Small molecule based inhibitors of PSMA have promised to provide sensitive detection of primary and metastatic prostate tumors. Although significant progress has been made, many of the radiolabeled imaging agents exhibit non-specific background binding. Prevailing tracer designs focus on high affinity urea-based inhibitors with strategically placed hydrophobic patches that interact favorably with the substrate tunnel of PSMA. We hypothesized that a novel PSMA inhibitor design incorporating highly negatively charged linkers may minimize non-specific binding and decrease overall background.

METHODS

Through iterative redesign, we generated a series of PSMA inhibitors with highly negatively charged linkers that connect to urea inhibitors and bulky radionuclide chelates. We then performed in vivo imaging and biodistribution studies with the radiolabeled tracers.

RESULTS

The tracers derived from our iterative redesign have affinities for PSMA comparable to the "parent" urea ligand Cys-C(O)-Glu. Using a fluorine-18 labeled PSMA targeting tracer, we found that these highly negatively charged molecules exhibit rapid renal excretion with minimal non-specific binding. The biodistribution data at 2 hr showed 4.6%ID/g PC3-PIP tumor uptake with spleen, liver, bone, and blood background levels of 0.1%, 0.17%, 0.1%, and 0.04%, respectively.

CONCLUSION

Placement of multiple negative charges in the linker region of PSMA tracers significantly reduced the non-specific background binding without significant reduction of binding affinity. This increased tumor/background contrast in positron emission tomography promises to provide more sensitive tumor detection while decreasing the overall radiation exposure to patients.

Transperineal ultrasound-guided 12-core prostate biopsy: an extended approach to diagnose transition zone prostate tumors

Objective

Transperineal ultrasound-guided (TPUS) 12-core prostate biopsy was evaluated as an initial strategy for the diagnosis of prostate cancer, The distribution of prostate cancer lesions was assessed with zone-specific biopsy.

Methods

From January 2010 to December 2012, 287 patients underwent TPUS-guided 12-core prostate biopsy. Multiple cores were obtained from both the peripheral zone (PZ) and the transition zone (TZ) of the prostate. Participants' clinical data and the diagnostic yield of the cores were recorded and prospectively analyzed as a cross-sectional study.

Results

The diagnostic yield of the 12-core prostate biopsy was significantly higher compared to the 6-core scheme (42.16 vs. 21.6%). The diagnostic yield of the 10-core prostate biopsy was significantly higher compared to the 6-core scheme (37.6 vs. 21.6%). The 12-core scheme improved the diagnostic yield in prostates >50 ml (12-core scheme: 28.1% vs. 10-core scheme: 20.4%; p = 0.034).

Conclusions

The 12-core biopsy scheme is a safe and effective approach for the diagnosis of prostate cancer. TZ biopsies in patients with larger prostates should be included in the initial biopsy strategy.