Should ultrasound criteria of the prostate be redefined to better evaluate when and where to biopsy

"In-Bore" MRI-Guided Prostate Biopsy for Prostate Cancer Diagnosis: Results from 140 Consecutive Patients

Objectives

Transrectal ultrasound-guided biopsy (TRUS-GB) is the current reference standard procedure for diagnosis of prostate cancer (PCa) but this procedure has limitations related to the low detection rate (DR) described in the literature. The aim of the study was to evaluate the DR efficiency, and complication rate in a pure "in-bore" magnetic resonance imaging-guided biopsy (MRI-GB) series according to the Prostate Imaging Reporting and Data System, version 2 (PI-RADS v2).

Materials and Methods

From July 2015 to April 2018, a series of 142 consecutive patients undergoing MRI-GB were prospectively enrolled. According to the European Society of Urogenital Radiology guidelines, the presence of clinically significant PCa (csPCa) on multiparametric magnetic resonance imaging was defined as equivocal, likely, or highly likely according to a PI-RADS v2, score of 3, 4, or 5, respectively.

Results

Of 142 patients, 76 (53.5%) were biopsy naive and 66 (46.5%) had ≤ 1 previous negative set of random TRUS-GB findings. The MRI-GB findings were positive in 75 of 142 patients with a DR of 52.8%. Of the 76 patients with ≤ 1 previous set of TRUS-GB, 43 had PCa found by MRI-GB, with a DR of 57.3%. The DR in the 66 biopsy-naive patients was 48% (32/66). Of the 75 patients with positive biopsy findings, 54 (80.5%) were found to have csPCa on histological examination. Of these 54 patients, 28 had an International Society of Urological Pathology grade 2; 5 had grade 3, 19 had grade 4, and 2 had grade 5. Considering the anatomic distribution of the index lesions using the PI-RADS v2 scheme, the probability of PCa was greater for lesions located in the peripheral zone (55 of 75, 73.3%) than for those in the central zone (20 of 75, 26.7%).

Conclusions

Our study conducted on 142 patients confirmed the greater DR of csPCa by MRI-GB, with a very low number of cores needed and a negligible incidence of complications, especially in patients with a previous negative biopsy. MRI-GB is optimal for the diagnosis of anterior and central lesions.

Internalization of secreted antigen-targeted antibodies by the neonatal Fc receptor for precision imaging of the androgen receptor axis

Targeting the androgen receptor (AR) pathway prolongs survival in patients with prostate cancer, but resistance rapidly develops. Understanding this resistance is confounded by a lack of noninvasive means to assess AR activity in vivo. We report intracellular accumulation of a secreted antigen-targeted antibody (SATA) that can be used to characterize disease, guide therapy, and monitor response. AR-regulated human kallikrein-related peptidase 2 (free hK2) is a prostate tissue-specific antigen produced in prostate cancer and androgen-stimulated breast cancer cells. Fluorescent and radio conjugates of 11B6, an antibody targeting free hK2, are internalized and noninvasively report AR pathway activity in metastatic and genetically engineered models of cancer development and treatment. Uptake is mediated by a mechanism involving the neonatal Fc receptor. Humanized 11B6, which has undergone toxicological tests in nonhuman primates, has the potential to improve patient management in these cancers. Furthermore, cell-specific SATA uptake may have a broader use for molecularly guided diagnosis and therapy in other cancers.

Transrectal electrical impedance tomography of the prostate: spatially coregistered pathological findings for prostate cancer detection

PURPOSE

Prostate cancer ranks as one of the most common malignancies and currently represents the second leading cancer-specific cause of death in men. The current use of single modality transrectal ultrasound (TRUS) for biopsy guidance has a limited sensitivity and specificity for accurately identifying cancerous lesions within the prostate. This study introduces a novel prostate cancer imaging method that combines TRUS with electrical impedance tomography (EIT) and reports on initial clinical findings based on in vivo measurements.

METHODS

The ultrasound system provides anatomic information, which guides EIT image reconstruction. EIT reconstructions are correlated with semiquantitative pathological findings. Thin plate spline warping transformations are employed to overlay electrical impedance images and pathological maps describing the spatial distribution of prostate cancer, with the latter used as reference for data analysis. Clinical data were recorded from a total of 50 men prior to them undergoing radical prostatectomy for prostate cancer treatment. Student's t-tests were employed to statistically examine the electrical property difference between cancerous tissue and benign tissue as defined through histological assessment of the excised gland.

RESULTS

Example EIT reconstructions are presented along with a statistical analysis comparing EIT and pathology. An average transformation error of 1.67% is found when 381 spatially coregistered pathological images are compared with their target EIT reconstructed counterparts. At EIT signal frequencies of 0.4, 3.2, and 25.6 kHz, paired-testing demonstrated that the conductivity of cancerous regions is significantly greater than that of benign regions ( p < 0.0304).

CONCLUSIONS

These preliminary clinical findings suggest the potential benefits electrical impedance measurements might have for prostate cancer detection.

The role of metabolic imaging in radiation therapy of prostate cancer

The goal of this study was to correlate prostatic metabolite concentrations from snap-frozen patient biopsies of recurrent cancer after failed radiation therapy with histopathological findings, including Ki-67 immunohistochemistry and pathologic grade, in order to identify quantitative metabolic biomarkers that predict for residual aggressive versus indolent cancer. A total of 124 snap-frozen transrectal ultrasound (TRUS)-guided biopsies were acquired from 47 men with untreated prostate cancer and from 39 men with a rising prostate-specific antigen and recurrent prostate cancer following radiation therapy. Biopsy tissues with Ki-67 labeling index ≤ 5% were classified as indolent cancer, while biopsy tissues with Ki-67 labeling index > 5% were classified as aggressive cancer. The majority (15 out of 17) of cancers classified as aggressive had a primary Gleason 4 pattern (Gleason score ≥ 4 + 3). The concentrations of choline-containing phospholipid metabolites (PC, GPC, and free Cho) and lactate were significantly elevated in recurrent cancer relative to surrounding benign tissues. There was also a significant increase in [PC] and reduction in [GPC] between untreated and irradiated prostate cancer biopsies. The concentration of the choline-containing phospholipid metabolites was significantly higher in recurrent aggressive (≈ twofold) than in recurrent indolent cancer biopsies, and the receiver operating characteristic (ROC) curve analysis of total choline to creatine ratio (tCho/Cr) demonstrated an accuracy of 95% (confidence interval = 0.88-1.00) for predicting aggressive recurrent disease. The tCho/Cr was significantly higher for identifying recurrent aggressive versus indolent cancer (tCho/Cr = 2.4 ± 0.4 versus 1.5 ± 0.2), suggesting that use of a higher threshold tCho/Cr ratio in future in vivo (1)H MRSI studies could improve the selection and therapeutic planning for patients who would benefit most from salvage focal therapy after failed radiation therapy.

Clinical utility of endorectal MRI-guided prostate biopsy: preliminary experience

PURPOSE

To investigate the potential clinical utility of endorectal MRI-guided biopsy in patients with known or suspected prostate cancer.

MATERIALS AND METHODS

We prospectively recruited 24 men with known or suspected prostate cancer in whom MRI-guided biopsy was clinically requested after multiparametric endorectal MRI showed one or more appropriate targets. One to six 18-gauge biopsy cores were obtained from each patient. Transrectal ultrasound guided biopsy results and post MRI-guided biopsy complications were also recorded.

RESULTS

MRI-guided biopsy was positive in 5 of 7 patients with suspected prostate cancer (including 2 of 4 with prior negative ultrasound-guided biopsies), in 8 of 12 with known untreated prostate cancer (including 5 where MRI-guided biopsy demonstrated a higher Gleason score than ultrasound guided biopsy results), and in 3 of 5 with treated cancer. MRI-guided biopsies had a significantly higher maximum percentage of cancer in positive cores when compared with ultrasound guided biopsy (mean of 37 ± 8% versus 13 ± 4%; P = 0.01). No serious postbiopsy complications occurred.

CONCLUSION

Our preliminary experience suggests endorectal MRI-guided biopsy may safely contribute to the management of patients with known or suspected prostate cancer by making a new diagnosis of malignancy, upgrading previously diagnosed disease, or diagnosing local recurrence.

A prospective pilot study of (89)Zr-J591/prostate specific membrane antigen positron emission tomography in men with localized prostate cancer undergoing radical prostatectomy

PURPOSE

In this pilot study we explored the feasibility of (89)Zr labeled J591 monoclonal antibody positron emission tomography of localized prostate cancer.

MATERIALS AND METHODS

Before scheduled radical prostatectomy 11 patients were injected intravenously with (89)Zr-J591, followed 6 days later by whole body positron emission tomography. Patients underwent surgery the day after imaging. Specimens were imaged by ex vivo micro positron emission tomography and a custom 3 Tesla magnetic resonance scanner coil. Positron emission tomography images and histopathology were correlated.

RESULTS

Median patient age was 61 years (range 47 to 68), median prostate specific antigen was 5.2 ng/ml (range 3.5 to 12.0) and median biopsy Gleason score of the 11 index lesions was 7 (range 7 to 9). On histopathology 22 lesions were identified. Median lesion size was 5.5 mm (range 2 to 21) and median Gleason score after radical prostatectomy was 7 (range 6 to 9). Eight of 11 index lesions (72.7%) were identified by in vivo positron emission tomography. Lesion identification improved with increasing lesion size for in vivo and ex vivo positron emission tomography (each p <0.0001), and increasing Gleason score (p = 0.14 and 0.01, respectively). Standardized uptake values appeared to correlate with increased Gleason score but not significantly (p = 0.19).

CONCLUSIONS

To our knowledge this is the first report of (89)Zr-J591/prostate specific membrane antigen positron emission tomography in localized prostate cancer cases. In this setting (89)Zr-J591 bound to tumor foci in situ and positron emission tomography identified primarily Gleason score 7 or greater and larger tumors, likely corresponding to clinically significant disease warranting definitive therapy. A future, larger clinical validation trial is planned to better define the usefulness of (89)Zr-J591 positron emission tomography for localized prostate cancer.

The incidence of hyperechoic prostate cancer in transrectal ultrasound-guided biopsy specimens

OBJECTIVES

To estimate the incidence of transrectal ultrasound (TRUS) hyperechoic lesions and of hyperechoic prostate cancer in TRUS-guided biopsy specimens.

METHODS

We prospectively studied 200 patients with total prostate-specific antigen values less than 20 ng/mL and/or positive results on digital rectal examination who had undergone TRUS-guided prostate biopsy. Each patient underwent laterally directed systemic six-core biopsy plus cores from abnormal TRUS lesions and rectally palpable lesions. Six to 10 biopsy cores were obtained from each patient.

RESULTS

Hyperechoic lesions were found in 19 patients (9.5%), hypoechoic in 83 (41.5%), and isoechoic in 98 (49.0%). Prostate cancer was diagnosed in 33.0% of study patients. Isoechoic findings on TRUS were recorded in 31.8% of patients diagnosed with prostate cancer, whereas 60.6% of cancers had hypoechoic and 7.6% hyperechoic lesions. There was no significant difference in the mean Gleason score between isoechoic cancers (mean 5.4) and hypoechoic cancers (mean 5.6). However, hyperechoic cancers had a mean Gleason score of 7.0, which was higher when compared with isoechoic and hypoechoic cancers.

CONCLUSIONS

Biopsy of hyperechoic lesions was positive for prostate cancer in a higher percentage of patients than previously reported in the literature, and Gleason score of these cancers was higher when compared with isoechoic and hypoechoic cancers.

Transrectal ultrasound guided biopsy for detecting prostate cancer: can random biopsies be reduced using the 4-dimensional technique?

We present our experience with a new technique of real time 3-dimensional sonography -- "4-dimensional Transrectal ultrasound (TRUS)" guided prostate biopsy. A total of 64 patients suspected of having prostate cancer based on an elevated prostate-specific antigen (greater than 4 ng/ml) formed the study group. A voluson (General Electric Vivid 3) ultrasound machine equipped with a transrectal 5-8 MHz curvilinear transducer was used. Sonography-guided prostate biopsy was performed following prostate imaging and volume calculation using 3D and 4D imaging. Biopsies of tumor suspicious areas, if present, as well as random biopsies were done. Histopathology showed prostate cancer in 15 (23.4%) and benign prostatic conditions in 49 (76.6%). TRUS examination in the 15 detected prostatic cancers showed that 6(40%) were hypoechoic, 4 (26.7%) were of mixed hypo and hyper echogenicity, 1 (6.7%) was hyperechoic, and 4 (26.7%) were isoechoic. TRUS finding of a hypoechoic lesion was significantly associated with malignancy. Other TRUS findings such as texture, calcification, and cysts did not show any association with malignancy. Mortality was zero after ultrasound-guided prostate biopsy. TRUS is the diagnostic test of choice in detection of prostate cancer. With advances in the technique of TRUS, effort is being made to identify more subtle lesions in order to reduce random biopsies. 4-Dimensional TRUS does improve the diagnostic accuracy but there is still a group of patients with "invisible" cancers. Therefore, the policy of random biopsies has to be continued till this incidence can be eliminated.

The Continuing Importance of Transrectal Ultrasound Identification of Prostatic Lesions

PURPOSE

In light of a recent tendency toward systematic nontargeted biopsy we reassessed whether identification and biopsy of ultrasonographically suspicious lesions contribute to the detection of prostate cancer.

MATERIALS AND METHODS

We reviewed prospectively gathered data on 7,426 transrectal ultrasound directed prostatic biopsies performed at our institution between June 16, 2000 and September 1, 2005. Patients underwent systematic biopsy (6 to 10 cores on initial biopsy and 13 to 15 on rebiopsy) with additional sampling of visible suspicious lesions. The RR for finding cancer in transrectal ultrasound positive and negative patients was calculated for likely independent prognostic variables.

RESULTS

A total of 3,828 biopsies (51.5%) were transrectal ultrasound negative and 3,598 (48.5%) were transrectal ultrasound positive. Prostate cancer was detected in 3,258 biopsies (43.9%). For each independent variable the RR for prostate cancer was higher if a sonographic lesion was present. A lesion increased the likelihood of cancer detection (57.8% vs 30.8%, RR 1.8). Biopsies from lesions identified by transrectal ultrasound had a greater median percent of the core involved with cancer (50% vs 10%, p <0.001) and they were more likely to have Gleason score 7 or greater (69.3% vs 28.3%, p <0.001).

CONCLUSIONS

Biopsies taken when a prostatic lesion is identified by transrectal ultrasound are almost twice as likely to show cancer than when no lesion is visible. These cancers are of higher grade and volume and, therefore, they are more clinically significant. The search for and targeted biopsy of suspicious lesions seen on transrectal ultrasound remains important for prostate cancer diagnosis.

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.

The technique of ultrasound guided prostate biopsy

This article discusses the preparations for ultrasound guided prostate biopsy, the conditions used and the process of performing a biopsy. The first step in preparing the patient is a cleansing enema before biopsy. Every author proposes the use of a preoperative antibiotic based prophylaxis. Differences may be found in the type, dosage and the duration of this preoperative application, which can last from 2 h to 2 days. For anaesthesia, lidocaine has been proposed, which may be used as a gel applied in the rectum or in the form of a prostate infiltrate. Quite a few colleagues administer a brief intravenous narcosis. A major debate goes on in respect of defining the number of biopsy samples needed. Hodge proposed sextant biopsy in 1989, for which we had false negative findings in 20% of all cases. Because of this, it has recently been suggested that eight or rather ten samples be taken. There are some who question even this. Twelve biopsy samples do offer an advantage compared to six, although in the case of eight this is not the case. We shall present an in depth discussion of the various opinions on the different numbers of biopsies samples required. For the sample site, the apex, the base and the middle part are proposed, and (completing the process) two additional samples can also be taken from the transition zone (TZ), since 20% of all prostate cancers originate from TZ. In case of a palpable nodule or any lesion made visible by TRUS, an additional, targeted, biopsy has to be performed. Certain new techniques like the 3-D Doppler, contrast, intermittent and others shall also be presented. The control of the full length of samples taken by a gun, as well as the proper conservation of the samples, are parts of pathological processing and of the technical tasks. A repeated biopsy is necessary in the case of PIN atypia, beyond which the author also discusses other indications for a repeated biopsy. We may expect the occurrence of direct postoperative complications and it is necessary to know how to treat these.

Contemporary impact of transrectal ultrasound lesions for prostate cancer detection

PURPOSE

Transrectal ultrasound (TRUS) guided systematic biopsy of the prostate is the gold standard diagnostic modality for prostate cancer. Consequently, the value of discrete hypoechoic lesions on TRUS lesions considered suspicious for cancer deserves meticulous reevaluation, specifically in the prostate specific antigen era when the majority of tumors diagnosed are nonpalpable. We studied whether the predictability of a biopsy core changes if the tissue comes from an isoechoic vs hypoechoic lesion.

MATERIALS AND METHODS

Prospective data were collected on 3,912 consecutive patients referred to our medical center between 1993 and 1999 for biopsy of the prostate. A sextant technique (apex, mid gland and base) with an additional core biopsy from the transitional zone was used. If a hypoechoic lesion was identified, the biopsy was taken from the lesion. Correlation between hypoechoic lesions, isoechoic areas and cancer detection for each core was performed.

RESULTS

A total of 31,296 cores were obtained from the cohort. Overall 2,642 (68%) cores had at least 1 hypoechoic lesion ultrasonographically. Cancer was detected in 675 (25.5%) and 323 (25.4%) patients with or without hypoechoic lesions (p = 0.97). The per core cancer detection was fairly uniform and averaged 9.3% and 10.4% for hypoechoic and isoechoic areas, respectively. The difference was not statistically significant (p = 0.3). Gleason scores were less than 7, 7 and greater than 7 in 46%, 34% and 20% of cases, respectively.

CONCLUSIONS

Despite the higher prevalence of cancers discovered in prostates with hypoechoic areas, the hypoechoic lesion itself was not associated with increased cancer prevalence compared with biopsy cores from isoechoic areas. For impalpable tumors TRUS findings are not contributory for staging.

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.