Nonpalpable prostate cancer: detection with MR imaging

Multiparametric magnetic resonance imaging in the management and diagnosis of prostate cancer: current applications and strategies

Magnetic resonance imaging (MRI) has become increasingly used worldwide in the diagnosis and management of prostate cancer. With advances in multiparametric MRI (mpMRI) technology, such as the use of dynamic contrast-enhanced and diffusion-weighted imaging sequences, observational studies have evaluated the utility for mpMRI in the continuum of prostate cancer management, from improving the detection of clinically significant prostate cancer, to planning radical prostatectomy and radiation therapy and the early detection of local recurrence. Furthermore, the potential for advanced imaging to reduce the burden of routine serial prostate needle biopsies for men on active surveillance is a promising area of research. MRI technology continues to evolve, and the potential applications in the management of prostate cancer care will require well-designed multi-institutional prospective clinical trials and rigorous efforts to standardize reporting and improve dissemination of expertise across institutions.

Susceptibility weighted imaging: a new tool in the diagnosis of prostate cancer and detection of prostatic calcification

BACKGROUND

Susceptibility weighted imaging (SWI) is a new MRI technique which has been proved very useful in the diagnosis of brain diseases, but few study was performed on its value in prostatic diseases. The aim of the present study was to investigate the value of SWI in distinguishing prostate cancer from benign prostatic hyperplasia and detecting prostatic calcification.

METHODOLOGY/PRINCIPAL FINDINGS

23 patients with prostate cancer and 53 patients with benign prostatic hyperplasia proved by prostate biopsy were scanned on a 3.0T MR and a 16-row CT scanner. High-resolution SWI, conventional MRI and CT were performed on all patients. The MRI and CT findings, especially SWI, were analyzed and compared. The analyses revealed that 19 out of 23 patients with prostate cancer presented hemorrhage within tumor area on SWI. However, in 53 patients with benign prostatic hyperplasia, hemorrhage was detected only in 1 patient in prostate by SWI. When comparing SWI, conventional MRI and CT in detecting prostate cancer hemorrhage, out of the 19 patients with prostate cancer who had prostatic hemorrhage detected by SWI, the prostatic hemorrhage was detected in only 7 patients by using conventional MRI, and none was detected by CT. In addition, CT demonstrated calcifications in 22 patients which were all detected by SWI whereas only 3 were detected by conventional MRI. Compared to CT, SWI showed 100% in the diagnostic sensitivity, specificity, accuracy, positive predictive value(PPV) and negative predictive value(NPV) in detecting calcifications in prostate but conventional MRI demonstrated 13.6% in sensitivity, 100% in specificity, 75% in accuracy, 100% in PPV and 74% in NPV.

CONCLUSIONS

More apparent prostate hemorrhages were detected on SWI than on conventional MRI or CT. SWI may provide valuable information for the differential diagnosis between prostate cancer and prostatic hyperplasia. Filtered phase images can identify prostatic calcifications as well as CT.

Is it time to consider a role for MRI before prostate biopsy?

The use of MRI in prostate cancer management is controversial and current guidelines underplay its role. Technological advances over the past 5 years, however, demand a re-evaluation of this position. In this article, we propose an increased use of MRI, not only in those with a diagnosis of prostate cancer but also for men before a prostate biopsy. The use of MRI before a biopsy can serve as a triage test in men with raised serum prostate-specific antigen levels, in order to select those for biopsy with significant cancer that requires treatment. This strategy could avoid biopsy, and hence unnecessary treatment, in those with no disease or insignificant cancer. In addition, avoidance of postbiopsy artifact caused by hemorrhage will lead to better local staging accuracy, while determining more accurately the disease burden. This approach could improve risk stratification by selecting those who require adjuvant therapy or dose escalation. Furthermore, MRI evaluation of cancer burden could be important in active surveillance regimens to select those needing intervention.

Prostate cancer: added value of subtraction dynamic imaging in 3T magnetic resonance imaging with a phased-array body coil

PURPOSE

To determine the added value of dynamic subtraction magnetic resonance (MR) imaging for the localization of prostate cancer.

MATERIALS AND METHODS

We examined 21 consecutive patients who underwent MR imaging in 3T unit with a phased-array body coil and then had radical prostatectomy. After T2-weighted fast spin-echo imaging, we performed a contrast-enhanced dynamic 3D gradient-echo imaging consisting of pre-contrast, 2 successive early-phased (first imaging was started just after the appearance of contrast material in the aortic bifurcation followed by second imaging 35 seconds after the initiation of first imaging) and one 5-minute delayed post-contrast series. Subtraction of pre- contrast images from corresponding post-contrast images of each phase was performed on the console.

RESULTS

On ROC analysis, the overall accuracy (Az value) of dynamic imaging combined with subtraction imaging was higher than T2-weighted imaging (p = 0.001) or conventional dynamic imaging alone (p = 0.074) for localization of cancer foci regardless of their zonal locations. Among pathologically verified 81 lesions, the mean volume of detected lesions with the subtraction images (n = 49, 0.69cm3) was smaller than with T2-weighted images (n = 14, 1.05cm3) or conventional dynamic images (n = 43, 0.71cm3).

CONCLUSION

For localization of small prostate cancer, additional subtraction for the dynamic imaging could be superior to both T2-weighted imaging and un-subtracted dynamic imaging.

Magnetic resonance imaging (MRI) anatomy of the prostate and application of MRI in radiotherapy planning

Radiotherapy planning for prostate carcinoma has traditionally been performed on computed tomography (CT)-images, on which both the high dose areas (prostate with or without seminal vesicles) as well as the low dose areas (surrounding structures, such as the rectum and bladder) are anatomically delineated. However, magnetic resonance imaging (MRI) provides much more information than CT; it can superbly demonstrate the internal prostatic anatomy, prostatic margins and the extent of prostatic tumours. Hence, MRI becomes a powerful tool to improve the accuracy of planning delineations in radiotherapy for prostate carcinoma and is rapidly gaining popularity in the radiotherapy community. The present paper reviews some important anatomical landmarks and acquisition protocols relevant to radiotherapy planning and explains the rationale and importance of close collaboration between radiotherapists and radiologists in optimizing radiotherapy for patients with prostate carcinoma.

How good is MRI at detecting and characterising cancer within the prostate?

OBJECTIVES

As well as detecting prostate cancer, it is becoming increasingly important to estimate its location, size and grade. We aim to summarise current data on the efficacy of magnetic resonance imaging (MRI) in this setting.

METHODS

Literature review of original research correlating MRI and histologic appearances.

RESULTS

Estimates of the sensitivity of MRI for the detection of cancer vary widely depending on method of analysis used and the definition of significant disease. Recent estimates using T2-weighted sequences and endorectal coils vary from 60% to 96%. Several groups have convincingly shown that dynamic contrast enhancement and spectroscopy each improve detection and that the sensitivity of MRI is comparable to and may exceed that of transrectal biopsy. Specificity is not yet good enough to consider the use of MRI in screening. High-grade and large tumours are detected significantly more often with both T2 sequences and spectroscopy. Estimation of size is improved by dynamic contrast and spectroscopy, but errors of >25% are common.

CONCLUSIONS

The sensitivity of MRI has improved to the point that it has potential in several new areas: targeting of biopsies, monitoring of disease burden both during active surveillance and after focal therapy, and exclusion of cancer in patients with a raised prostate-specific antigen level.

Conventional MRI Capabilities in the Diagnosis of Prostate Cancer in the Transition Zone

OBJECTIVES

Our objectives were to evaluate the diagnostic capabilities of conventional MRI for the accurate detection of prostate cancer within the transition zone and to compare the results with histopathologic examination results.

MATERIALS AND METHODS

One hundred sixteen prostate specimens with prostate cancer were consecutively obtained. Axial, sagittal, and coronal T2- and T1-weighted MR images with gadopentetate dimeglumine were independently reviewed by two radiologists. The diagnostic base criteria of the MR images were determined for detecting transition zone cancer as follows: lesions with A, uniform low intensity on T2-weighted images; B, homogeneous gadolinium enhancement; and C, irregular margins both on gadolinium-enhanced and T2-weighted images. Wilcoxon's rank sum and chi-square tests and receiver operating characteristic curves were used. Differences of less than 0.05 were considered significant.

RESULTS

Eighty-six lesions in the transition zone were analyzed. Histopathologic analysis showed 53 cancers and 33 benign lesions. The diagnostic sensitivity, specificity, and accuracy for cancer were 50%, 51%, and 51%, respectively with criteria A; 68%, 75%, and 71% with criteria B; and 60%, 72%, and 65% with criteria C. When base criteria were combined into criteria A-B, A-C, and B-C and then further divided into three subgroups, accuracy was found to be highest when the lesion satisfied any two criteria from A, B, and C than those of base criteria, combination criteria, and the other two subgroups.

CONCLUSION

The addition of gadolinium-enhanced MRI to T2-weighted imaging provides better accuracy for detecting cancerous transition zone lesions than the use of T2-weighted imaging alone.

Comparison of high-resolution echo-planar spectroscopic imaging with conventional MR imaging of prostate tumors in mice

High spectral and spatial resolution (HiSS) MRI of rodent tumors has previously been performed using conventional spectroscopic imaging to obtain images with improved contrast and anatomic detail. The work described here evaluates the use of much faster echo-planar spectroscopic imaging (EPSI) to acquire HiSS data from rodent tumor models of prostate cancer. A high-resolution EPSI pulse sequence was implemented on a 4.7 T Bruker scanner. Three-dimensional EPSI data were Fourier-transformed along the k-space and temporal (free-induction decay) axes to produce detailed water and fat spectra associated with each small image voxel. The data were used to generate images of spectral parameters, e.g. peak-height images for each small voxel. Two variants of EPSI were performed; gradient-echo or spin-echo excitation with EPSI readout. These imaging methods were tested in commonly used rodent prostate cancers, including seven mice implanted with non-metastatic AT2.1 (n=3) and metastatic AT3.1 (n=4) prostate tumors on the hind leg, and 10 mice implanted with LNCaP prostate cancers in situ. The peak-height images derived from EPSI datasets provide more detailed tumor anatomy, improved signal-to-noise and contrast-to-noise ratios compared with the gradient-echo or spin-echo images at all echo times. The results suggest that HiSS MRI data from small animal models of prostate cancer can be acquired using EPSI, and that this approach improves imaging of heterogeneous tissue and vascular environments inside the tumors compared with conventional MR techniques.

The magnetic resonance detected intraprostatic lesion in prostate cancer: planning and delivery of intensity-modulated radiotherapy

BACKGROUND AND PURPOSE

Local relapse after radiotherapy for prostate cancer mostly originates at the original tumor location. Dose escalation reduces local relapse rates. It may be of benefit to focus the highest dose to the intraprostatic lesion (GTVMRI) using intensity-modulated radiotherapy (IMRT). Therefore, the visualization of the GTVMRI and its inclusion into computer optimization is mandatory.

MATERIALS AND METHODS

Fifteen patients with prostatic adenocarcinoma were referred for IMRT. All these patients had a palpable lesion on digital rectal examination (DRE) and/or a PSA >10.0 ng/ml. A T2-weighted MR examination of the prostate was performed in order to detect a GTV(MRI) and correlate the location of the GTV(MRI) with the site of the tumour-containing cylinder (biopsy). Two IMRT plans were compared: a plan without the inclusion of the GTV(MRI) (IMRT-CONV) versus a plan including the GTV(MRI) into the plan optimization (IMRT-GTV(MRI)). For comparison, both physical and biological endpoints of the GTV(MRI), CTV, PTV and rectum were taken into account. After the finalization of the planning study, the IMRT-GTV(MRI) plans were clinically delivered using step-and-shoot IMRT. Acute gastro-intestinal (GI) and genito-urinary (GU) toxicity were recorded.

RESULTS

In all cases, the location of the GTV(MRI) corresponded with the site of the tumor containing biopsy cylinder. The mean and median distance of the GTV(MRI) to the anterior rectal wall was 3 and 2mm, respectively (range: 0-12 mm). For the GTV(MRI), its inclusion in the optimization led to a significant increase of all physical endpoints (P<0.01), without compromising the dose to the CTV, PTV and rectum. Mean GTV(MRI) dose was 78.3 Gy (IMRT-GTV(MRI)) versus 76.9 Gy (IMRT-CONV) (P<0.00001). All IMRT treatments were successfully delivered within 6 min. We did not observe grade 3 acute GI toxicity. One patient developed grade 3 GU toxicity (nocturia), that disappeared after administration of medication. Grade 2 GI and GU toxicity was observed in, respectively, four and six patients.

CONCLUSION

Using T2-weighted MR, the visualization of an intraprostatic lesion is feasible. The inclusion of the GTV(MRI) into planning optimization leads to a modest increase in dose, without compromising the dose to the CTV, PTV and organs at risk. The clinical delivery of these plans runs without problems. Acute toxicity is mild.

Detection of prostate cancer by integration of line-scan diffusion, T2-mapping and T2-weighted magnetic resonance imaging; a multichannel statistical classifier

A multichannel statistical classifier for detecting prostate cancer was developed and validated by combining information from three different magnetic resonance (MR) methodologies: T2-weighted, T2-mapping, and line scan diffusion imaging (LSDI). From these MR sequences, four different sets of image intensities were obtained: T2-weighted (T2W) from T2-weighted imaging, Apparent Diffusion Coefficient (ADC) from LSDI, and proton density (PD) and T2 (T2 Map) from T2-mapping imaging. Manually segmented tumor labels from a radiologist, which were validated by biopsy results, served as tumor "ground truth." Textural features were extracted from the images using co-occurrence matrix (CM) and discrete cosine transform (DCT). Anatomical location of voxels was described by a cylindrical coordinate system. A statistical jack-knife approach was used to evaluate our classifiers. Single-channel maximum likelihood (ML) classifiers were based on 1 of the 4 basic image intensities. Our multichannel classifiers: support vector machine (SVM) and Fisher linear discriminant (FLD), utilized five different sets of derived features. Each classifier generated a summary statistical map that indicated tumor likelihood in the peripheral zone (PZ) of the prostate gland. To assess classifier accuracy, the average areas under the receiver operator characteristic (ROC) curves over all subjects were compared. Our best FLD classifier achieved an average ROC area of 0.839(+/-0.064), and our best SVM classifier achieved an average ROC area of 0.761(+/-0.043). The T2W ML classifier, our best single-channel classifier, only achieved an average ROC area of 0.599(+/-0.146). Compared to the best single-channel ML classifier, our best multichannel FLD and SVM classifiers have statistically superior ROC performance (P=0.0003 and 0.0017, respectively) from pairwise two-sided t-test. By integrating the information from multiple images and capturing the textural and anatomical features in tumor areas, summary statistical maps can potentially aid in image-guided prostate biopsy and assist in guiding and controlling delivery of localized therapy under image guidance.

The value of endorectal MRI in the early diagnosis of prostate cancer

OBJECTIVE

Assess the value of endorectal MR imaging (EMRI) in the early diagnosis of prostate cancer (PCa) and compare this test to prostate specific antigen (PSA) and digital rectal examination (DRE) in the prediction of negative biopsies.

MATERIAL AND METHODS

92 patients with elevated PSA (>4 ng/ml) and/or abnormal DRE were studied. All patients underwent an EMRI previous to transrectal ultrasound guided needle sextant biopsies (3 cores in each peripheral zone), and were followed up. We performed a total of 184 biopsies: 92 patients underwent 1 biopsy; out of them, 61 patients underwent 2 biopsies, 27 patients 3 biopsies, 3 patients 4 biopsies and 1 patient 5 biopsies. 67 patients had a final negative biopsy and 25 had a final positive biopsy. Mean PSA was 10.44 ng/ml, and the mean % fPSA/tPSA was 0.20. Uni- and multivariate analysis and ROC curves were used to compare the accuracy of the different tests. The probability of positive biopsy with each technique was also assessed.

RESULTS

EMRI had a high negative predictive value (91.07%) and the highest accuracy (77%) of all tests, higher than PSA (62%). Mean PSA was not statistically different in patients with negative biopsies (9.44 ng/ml) and positive biopsies (11.8 ng/ml) (p=0.064). The association of EMRI-DRE-PSA had the highest accuracy (83%) significantly higher than DRE-PSA (70%). The probability of positive biopsy in patients with negative DRE and EMRI, and PSA values between 5 and 15 ng/ml was 5-10% at first and second biopsies, but decreased progressively on subsequent biopsies (<8% at third biopsy, <5% at fourth biopsy and <3% at fifth biopsy).

CONCLUSION

In patients with elevated PSA and/or abnormal DRE with two previous negative biopsies, an EMRI is a useful test to rule out PCa, when negative, and avoid subsequent biopsies, as they have a low chance of positive biopsy.

Magnetic resonance imaging of prostatic cancer: does detection vary between high and low gleason score tumors?

BACKGROUND

Both Gleason score and prostate-specific antigen (PSA) concentration are prognostic factors for prostate cancer. We assessed our ability to localize cancer lesions based on Gleason scores and PSA values by endorectal coil magnetic resonance imaging (MRI). We also evaluated whether the size of the prostate affects tumor detectability.

METHODS

We compared the findings of MRI and histopathological results of radical prostatectomy specimens from 63 patients; they were divided into four groups, based on Gleason score and also on serum PSA concentration. Furthermore, the possible effect of prostatectomy specimen weight on MRI interpretation was examined.

RESULTS

A highly significant difference appeared in detection of cancer lesions based on their differentiation grade. No statistically significant difference existed between PSA groups in detection of tumors, but the large size of the prostate seemed to render image interpretation more difficult.

CONCLUSIONS

Endorectal MRI detects poorly differentiated prostate cancer lesions more accurately than clinically insignificant tumors.

Dynamic contrast enhanced MRI of prostate cancer: correlation with morphology and tumour stage, histological grade and PSA

AIM

To quantify MRI enhancement characteristics of normal and abnormal prostatic tissues and to correlate these with tumour stage, histological grade and tumour markers.

MATERIALS AND METHODS

Quantitative gradient recalled echo MR images were obtained following bolus injection of gadopentetate dimeglumine in 48 patients with prostate cancer. Turbo spin-echo T2-weighted images at the same anatomical position were reviewed for the presence of tumours (45 regions), normal peripheral zone (33 regions), and normal appearing central gland (30 regions). Time-signal intensity parameters (onset time, mean gradient and maximal amplitude of enhancement and wash-out score) and modelling parameters (permeability surface area product, lesion leakage space and maximum gadolinium concentration) were correlated with tumour stage, histological grade (Gleason score) and serum prostatic specific antigen (PSA) levels.

RESULTS

Significant differences were noted between peripheral zone and tumour with respect to signal intensity and modelling parameters (P = 0.0001), except onset time. No differences between central gland and tumour enhancement values were seen. There was weak correlation between MRI tumour stage and tumour vascular permeability (r(2) = 12%; P = 0.02) and maximum tumour gadolinium concentration (r(2) = 14%; P = 0.015). However, no significant correlations were seen with Gleason score or PSA levels.

CONCLUSION

Quantification of MR contrast enhancement characteristics allows tissue discrimination in prostate cancer consistent with known variations in microvessel density estimates.

The value of dynamic MR imaging for hypointensity lesions of the peripheral zone of the prostate

The aim was to evaluate the role of dynamic magnetic resonance (MR) imaging for prostatic carcinoma. Forty-two men with clinical suspicion of a prostatic carcinoma underwent MR imaging. Dynamic MR was performed, followed by postcontrast T1-weighted imaging with fat suppression. Histologic diagnosis was 21 prostatic carcinomas (in 19 patients), 21 benign tissues, and 2 chronic prostatitis. The diagnostic accuracy was 75% for T2-weighted images, and 79% for dynamic images. The accuracy of the combination of dynamic MR images with postcontrast T1-weighted images was 82%. It was concluded that dynamic MR imaging was useful in differentiation of low intensity lesions in the peripheral zone.

Prostate imaging may not be necessary in nonpalpable carcinoma of the prostate

OBJECTIVES

Stage T1c carcinoma of the prostate is defined as a nonpalpable carcinoma (NPC-P) that is not visible by imaging and is identified by needle biopsy performed because of elevated prostate-specific antigen (PSA) concentrations. The purpose of this study was to define the incidence of normal findings on transrectal ultrasound (TRUS) and/or endorectal coil magnetic resonance imaging (EMRI) among patients with NPC-P, as well as to investigate the value of differentiating patients with Stage T1c disease from all other patients with NPC-P.

METHODS

The records of 2211 patients diagnosed with prostate carcinoma between 1988 and 1995 were reviewed to identify 291 men with NPC-P. TRUS and EMRI reports were analyzed with regard to the presence and laterality of hypoechoic nodules or low-signal areas reported on T2-weighted images, respectively. Ninety percent of patients (n = 262) had at least six prostate biopsies, 185 patients (64%) underwent both TRUS and EMRI, 224 (77%) had TRUS, and 251 (86%) had an EMRI study.

RESULTS

Results were considered normal in 101 (47%) of 214 patients undergoing TRUS, in 58 (23%) of 249 undergoing EMRI, and in 22 (12%) of 185 undergoing both TRUS and EMRI. For the side of the prostate with positive biopsy results, correlation with imaging abnormalities was better for EMRI than for TRUS (39% versus 24%). There was no significant difference in mean PSA value, distribution of Gleason score, or unilateral versus bilateral positive biopsy results among patients with normal versus abnormal findings on both TRUS and EMRI.

CONCLUSIONS

(1) Only 12% of men with NPC-P have no TRUS or EMRI abnormalities, fulfilling the criteria for Stage T1c prostate carcinoma. (2) Those patients with Stage T1c disease do not differ from patients with NPC-P up-staged by TRUS or EMRI, with regard to pretreatment PSA levels, Gleason scores, and the probability of having bilateral rather than unilateral positive biopsy results. (3) The value of classifying patients with NPC-P into Stage T1c versus higher stages of prostate carcinoma on the basis of imaging should be questioned.

Can aggressive prostatic carcinomas be identified and can their natural history be altered by treatment?

The factors that determine tumor aggressiveness are multifactorial: age, stage, and grade. Even a well differentiated tumor in a young patient may be aggressive someday because of genetic drift and tumor heterogeneity. In a recent review of 826 favorably selected cases managed with conservative therapy, metastatic disease had developed in 19% with grade I tumors, 42% with grade II, and 74% with grade III at 10 years. Recognizing that < 20% of men present with grade I disease, most prostate cancers are a threat to life in men who are going to live longer than 10 years. On the other hand, some tumors at presentation are too far advanced to cure. To improve the accuracy of preoperative staging in identifying these cases, we have developed nomograms based upon clinical stage, grade, and serum prostate-specific antigen (PSA). Traditionally, patients with high-grade tumors (Gleason 8-10) were never considered candidates for radical prostatectomy because of their poor expectancy for long-term survival. However, with improvements in the staging of prostate cancer and with a reduction in the morbidity of radical prostatectomy, a subset of these patients are potential candidates for curative therapy. We have recently studied the clinical outcome of 72 men with Gleason scores of 8-10 on needle biopsies who presented with clinically localized disease (9 T1c, 22 T2a, 17 T2b, 13 T2c, and 11 T3a). Of the 63 men who underwent radical prostatectomy, 46 (68%) had negative lymph nodes; nine did not undergo surgery because of positive lymph nodes identified from frozen section. The actuarial likelihood of an undetectable serum PSA at 5 years was 43% for men with negative lymph nodes and 45% for men with organ-confined disease. Thus, with proper evaluation, some men with even the most aggressive tumors can be cured by surgery if their pelvic lymph nodes are negative.

The role of intravenous contrast enhancement in magnetic resonance imaging of prostatic carcinoma

Although magnetic resonance imaging (MRI) has been shown to be a promising technique for staging prostatic carcinoma, its accuracy in detection of extraprostatic spread and seminal vesical invasion is subject to considerable error. The role of dynamic MRI, following bolus intravenous contrast medium, in depicting carcinoma of the prostate was evaluated and the information provided by this technique compared with unenhanced images. Spin-echo T1-weighted, T2-weighted, bolus contrast enhanced and delayed post-contrast enhanced T1-weighted images were obtained in 20 patients with histologically proven adenocarcinoma of the prostate. Tumour was identified in all of the patients studied. When compared with unenhanced and delayed post-contrast enhanced images, dynamic bolus contrast enhanced images enabled the best definition of tumour within the gland in 50% of patients and demonstrated extracapsular spread more clearly in 80% of patients. It is concluded that dynamic bolus contrast enhancement may be useful in selected patients with prostatic carcinoma by enabling tumour margins to be depicted more clearly.

Negative repeat transurethral resection of prostate fails to identify patients with stage A1 prostatic carcinoma at lower risk of progression: a long-term study

Stage A1 (low-grade and low-volume) adenocarcinoma is associated with a low likelihood of progression. Repeat transurethral resection has been used to identify patients at increased risk (residual cancer noted) as well as those at low risk of progression (no residual cancer noted). We recently evaluated the ability of this technique to define a low-risk patient population. We reviewed the records of 24 patients who underwent repeat transurethral resection after they were identified as having Stage A1 prostatic cancer on initial resection (Gleason score < 5, tumor volume comprising < 5% of the resection specimen). Despite no evidence of residual carcinoma on repeat resection, 3 patients (13%) progressed at a mean follow-up of seven years (2 locally, 1 locally and distantly). We conclude that repeat resection does not effectively evaluate the risk of progression and that other techniques including transrectal ultrasonography and serial prostate-specific antigen measurements should be similarly evaluated.

Clinical diagnosis of prostate cancer

BACKGROUND

The clinical diagnosis of localized prostate carcinoma in the asymptomatic male has been based on a careful digital rectal examination (DRE).

METHODS

The DRE, prostate specific antigen (PSA), transrectal ultrasonography (TRUS), prostate needle biopsy (PNB), and other modalities are examined for their role in prostate cancer diagnosis.

RESULTS

Up to 20% of localized prostatic cancer is still diagnosed "retrospectively" on transurethral resection (TURP) for clinically benign disease and prostatism. The role of fine-needle aspiration (FNA), flow cytometric study (FCM), and magnetic resonance imaging (MRI) in the diagnosis of prostate cancer is limited.

CONCLUSIONS

Those men older than 50 years of age who have lower tract symptoms, either obstructive or irritative, or who have abnormal serum levels of PSA, regardless of DRE findings, are advised to undergo TRUS with ultrasound-guided PNB.