Staging of Prostate Cancer

Transrectal Ultrasound Findings of Prostate Cancer Mimicking Primary Rectal Tumor

Two patients with disseminated prostatic cancer underwent transrectal ultrasonographic examination. In the rectal wall, at the prostatic level, tumor infiltration was seen without obvious communication to the prostate. Biopsy demonstrated adenocarcinoma, and immunohistochemic staining for prostatic specific antigen (PSA) was positive. We recommend the application of PSA staining in biopsy specimens of unclear rectal masses.

Imaging prostate cancer: a multidisciplinary perspective

The major goal for prostate cancer imaging in the next decade is more accurate disease characterization through the synthesis of anatomic, functional, and molecular imaging information. No consensus exists regarding the use of imaging for evaluating primary prostate cancers. Ultrasonography is mainly used for biopsy guidance and brachytherapy seed placement. Endorectal magnetic resonance (MR) imaging is helpful for evaluating local tumor extent, and MR spectroscopic imaging can improve this evaluation while providing information about tumor aggressiveness. MR imaging with superparamagnetic nanoparticles has high sensitivity and specificity in depicting lymph node metastases, but guidelines have not yet been developed for its use, which remains restricted to the research setting. Computed tomography (CT) is reserved for the evaluation of advanced disease. The use of combined positron emission tomography/CT is limited in the assessment of primary disease but is gaining acceptance in prostate cancer treatment follow-up. Evidence-based guidelines for the use of imaging in assessing the risk of distant spread of prostate cancer are available. Radionuclide bone scanning and CT supplement clinical and biochemical evaluation (prostate-specific antigen [PSA], prostatic acid phosphate) for suspected metastasis to bones and lymph nodes. Guidelines for the use of bone scanning (in patients with PSA level > 10 ng/mL) and CT (in patients with PSA level > 20 ng/mL) have been published and are in clinical use. Nevertheless, changes in practice patterns have been slow. This review presents a multidisciplinary perspective on the optimal role of modern imaging in prostate cancer detection, staging, treatment planning, and follow-up.

[Risk factors for positive surgical margins following radical prostatectomy: review]

The presence of positive surgical margins on radical prostatectomy specimen is an adverse prognostic factor. Parameters supposed to influence surgical margin status includes pathology method analysis, surgical technique, tumoral and non tumoral patient parameters, and neoadjuvant hormonal therapy. Regarding the surgical technique, surgeon's experience and neuro-vascular bundles preservation are the most important factors of margin status, whereas surgical approach, bladder neck conservation, intraoperative frozen analysis, and bleeding are minor factors. Non tumoural patient parameters influencing surgical margin status include patient's age and weight, and prostate gland weight. For tumoural parameters, pathological stage and tumour volume are more important factors than the tumor grade and PSA. Five preoperative tumoral risk factors of positive surgical margins are particularly important, including abnormal digital rectal examination, preoperative PSA 10 ng/mL, biopsy Gleason score >7, number of positive biopsy cores > or = 2, and suspicion of extraprostatic extension on radical prostatectomy specimen.

Prostatic adenocarcinoma metastasis in the thyroid gland

Metastasis from prostate to thyroid gland is very uncommon. Here we report a 77-year-old man who was admitted to the hospital because of a nodular goiter. A fine-needle aspiration biopsy of the nodule showed metastatic prostatic adenocarcinoma. This is the second case of a metastatic prostate carcinoma to the thyroid gland.

Clinical staging of prostate cancer: reproducibility and clarification of issues

The American Joint Committee on Cancer (AJCC) staging system for prostate cancer adopted in 1992 is based on tumor-node-metastasis (TNM) designations. It has been widely accepted for use in local and advanced disease. The purpose of this study was to assess reproducibility of staging among observers and to help clarify staging issues. Twelve prostate cancer cases were sent to 20 physicians with special expertise in prostate cancer including eight urologists, eight radiation oncologists, and four medical oncologists. Physicians were asked to assign a stage based on the 1992 AJCC clinical staging. The most frequently reported stage assigned to each case was taken to be the consensus. Agreement was the percentage of physicians who reported that particular stage. Seventy-five percent of the physicians responded. The overall agreement for assignment of T stage was 63.9%. Differences were found by specialty for inclusion of available information in designating a T stage. The overall agreement for N stage was 73.8%. The most common designation was Nx regardless of availability of a computed tomography scan. The overall agreement for M stage was 76.6%. Without a bone scan the most common designation was Mx regardless of Gleason grade or prostate-specific antigen (PSA). A frequent comment was that PSA was more indicative of disease extent than current clinical staging. The reproducibility of the 1992 clinical AJCC staging is poor even among experts in the field. This problem arises primarily from disagreement regarding which studies are included in assigning a stage. Some of these difficulties are addressed in the 1997 revision. However, the clinical staging does not address the true biological significance of disease in many instances.

Prostate cancer: assessment of risk using digital rectal examination, tumor grade, prostate-specific antigen, and systematic biopsy

Refinement in the local staging and risk assessment for prostate cancer patients utilizing clinical parameters is ongoing. DRE, tumor grade, and PSA provide some useful information for risk assessment in individual patients. More recent studies using percent free PSA levels and systematic biopsy results have added additional staging information and may play a more significant role in the future in risk assessment. This information should supplement additional imaging tests in the management of these patients.

Significant changes in volume of seminal vesicles as determined by transrectal sonography in relation to age and benign prostatic hyperplasia

We evaluated the changes in volume of the seminal vesicles as determined by transrectal sonography in terms of the possible relationship with aging, lower urinary tract symptoms and benign prostatic hyperplasia (BPH) in community based populations in Japan. In 641 men (55-86 year, mean 67) on a mass screening program for prostatic diseases, the maximum horizontal area of the seminal vesicles (MHA) was compared with age, American Urological Association (AUA) symptom index scores and transrectal ultrasonic parameters of the prostate including prostatic volume, transition zone (TZ) volume, TZ index and presumed circle area ratio (PCAR). Simple regression analyses demonstrated that MHA correlated significantly with age, prostatic volume, TZ volume, TZ index and PCAR, but not with AUA symptom index scores. Multiple regression analysis revealed age, prostatic volume and PCAR to be independent determinants of MHA. There was a difference in MHA between subjects with BPH (7.1+/-2.5 cm2) and those with a normal prostate (5.6+/-2.1 cm2) with a statistical significance. In the morphological evaluation of the seminal vesicles, the significant influence of age and BPH has to be taken into account.

Prostate cancer staging: correlation between ultrasound determined tumor contact length and pathologically confirmed extraprostatic extension

PURPOSE

We determine whether a new parameter, the amount of tumor in contact with the fibromuscular rim (capsule) of the prostate, correlates with extraprostatic extension, and ascertain whether estimating the new parameter using transrectal ultrasonography can predict extraprostatic extension.

MATERIALS AND METHODS

We analyzed step sectioned prostatectomy specimens from 189 patients who had had positive peripheral zone biopsies. We measured the contact length, maximum length (mm.) of the portion of the peripheral zone cancer that was in contact with the fibromuscular rim, and determined the contact ratio from the quotient (%) of the contact length divided by the tumor circumference. We evaluated the correlation between the pathological and ultrasound measurements of these parameters, as well as the accuracy of these criteria for predicting microscopic extraprostatic extension.

RESULTS

Among the 189 cancers there was a significant difference (p <0.0001) between organ confined tumors and tumors with extraprostatic extension in contact length and contact ratio. There was a positive correlation (r = 0.691) between the contact lengths measured ultrasonically and histologically among 95 patients who had hypoechoic lesions associated with positive biopsies. A receiver operating characteristics curve of the ability of ultrasound estimated contact length to predict extraprostatic extension revealed the best cutoff value to be 23 mm. with 77% accuracy. Logistic regression analysis revealed that pathological contact length correlated better with extraprostatic extension than tumor volume, Gleason score, prostate specific antigen (PSA) level and pathological contact ratio. The best preoperative predictor of extraprostatic extension was the ultrasound contact length, followed by the contact ratio, PSA value, percentage of the biopsy specimen that was cancer and presence of perineural invasion in the biopsy specimen. Multiple logistic regression analysis revealed that the predictability of ultrasound contact length was improved by considering PSA value also. Probability plots for predicting extraprostatic extension were developed by combination of ultrasound contact length with PSA value.

CONCLUSIONS

The length of tumor contact with the fibromuscular rim is more significantly related to extraprostatic extension than tumor volume, PSA level and tumor grade. For hypoechoic cancers a new ultrasound staging criterion, contact length, has been defined. For men who are clinically candidates for radical prostatectomy and have peripheral zone hypoechoic cancers the combination of ultrasound contact length and PSA value is the best predictor of extraprostatic extension.

MR imaging of the prostate and bladder

Magnetic resonance imaging has become an important imaging modality for the male pelvis. Its unparalleled ability to depict soft tissue structures and highlight pathology have made it the best method for determining the extent of many disease processes. This article reviews the use of MR to evaluate diseases of the prostate gland and bladder. In both, the major indication for imaging is the local staging of cancer, and MR is currently the best imaging modality. This article will discuss the critical clinical issues concerning prostate cancer and neoplasms of the bladder, and the contribution of MR imaging.

Role of transrectal ultrasound and prostate biopsy

Transrectal ultrasound (TRUS) has revolutionized our ability to image the human prostate. In the present review, we have attempted to present salient observations with respect to this modality. We emphasize its use in combination with biopsy in men who are considered at risk for harboring carcinoma. The relevant English literature is reviewed. In addition, our experience with 2,231 consecutive ultrasound-guided biopsies performed at the University of Washington and the Seattle VA Medical Center is analyzed. TRUS appears to have its primary use in directing the biopsy needle into suspicious areas and in performing the so-called systematic sector approach to biopsy. The role of transrectal ultrasound in staging established malignancy or in monitoring men following therapy remains to be defined. In our experience, carcinoma was detected in 27.2% of the subjects. Carcinoma was found in 30.7% of patients with a hypoechoic sector. Of note, 18.4% of men had their only carcinoma found in isoechoic areas. Failure to biopsy isoechoic sectors would have resulted in missing almost 20% of men with carcinoma. The role of TRUS in men with initially negative biopsy is also discussed. In summary, ultrasound guided biopsy is a useful addition to our armamentarium, particularly with respect to performing biopsy. Future advances in this modality include image enhancement utilizing computer technology as well as the potential additive role of color flow ultrasound.

Construction and application of hierarchical decision tree for classification of ultrasonographic prostate images

A non-parametric algorithm is described for the construction of a binary decision tree classifier. This tree is used to correlate textural features, computed from ultrasonographic prostate images, with the histopathology of the imaged tissue. The algorithm consists of two parts; growing and pruning. In the growing phase an optimal tree is grown, based on the concept of mutual information. After growing, the tree is pruned by an alternating interaction of two data sets. Moreover, the structure and performance of the constructed tree are compared to the results using a slightly modified corresponding growing and pruning algorithm. The modified algorithm provides better retrospective and prospective classification results than the original algorithm. The use of the tree for automated cancer detection in ultrasonographic prostate images results in retrospective and prospective accuracy of 77.9% and 72.3%, respectively. Using this tissue characterisation, a supporting tool is provided for the interpretation of transrectal ultrasonographic images.

A three-dimensional ultrasound prostate imaging system

We have developed a three-dimensional (3D) transrectal ultrasound imaging system, based on using a motorized 5 MHz transducer assembly, rotated under microcomputer control, to collect a series of 100 two-dimensional (2D) images, digitized by a video frame-grabber. These are then reconstructed into a 3D image on a computer workstation, permitting the prostate anatomy to be visualized in three dimensions, and distance and volume measurements to be performed. The accuracy of the distance measurements was assessed with a string test phantom, and that of the volume measurements with balloons of known sizes. Also, the resolution degradation engendered by the reconstruction algorithm was assessed by comparing the full-width at half-maximum (FWHM) of string cross-sectional images in the 3D image to their 2D counterparts. The results show that distance and volume measurements are both accurate to about +/- 1%, and that the reconstruction algorithm increases the mean FWHM by 8 +/- 3% axially and 3 +/- 3% laterally.

Optimization of prostate carcinoma staging: comparison of imaging and clinical methods

PURPOSE

The diagnostic value of endorectal coil MRI, body coil MRI, transrectal ultrasound, digital rectal examination and PSA levels were prospectively analysed in order to define the most accurate preoperative staging method.

METHODS

33 patients with prostate carcinoma, who underwent subsequent prostatectomy, were enrolled in the study and examined on a 1.5T system using the body coil as well as the endorectal surface coil before and after the administration of contrast material. The results were compared to digital rectal examination, prostate specific antigen levels and endorectal ultrasound.

RESULTS

Staging accuracy of endorectal coil MRI was 87.9% with a sensitivity of 88.9% and specificity of 86.7%. For body coil MRI, the staging accuracy was 75.7%, the sensitivity 66.7% and the specificity 87.9%, for transrectal ultrasound 69.6%, 41.7% and 100% and for the digital rectal examination 56.6%, 33.3% and 100%, respectively. Prediction was improved by combining results of endorectal coil MRI with PSA values.

CONCLUSION

Endorectal ultrasound and digital rectal examination both had a tendency to underestimate the extent of the lesion. Endorectal coil MRI proved to be the best preoperative staging method. In combination with PSA values, diagnostic accuracy could be further improved. Therefore, local staging of prostate cancer could be based on these two parameters alone.

Topography of neovascularity in human prostate carcinoma

BACKGROUND

All neoplasms require angiogenesis and resulting neovascularity for growth. The authors and others have confirmed the staging and prognostic significance of quantitative microvascularity density (MVD) in human prostate carcinoma (CAP). In the present investigation, the authors sought to identify the specific site of neovascularity within the neoplasm and adjacent benign tissue.

METHODS

Histologically benign and malignant tissues from 14 random radical prostatectomy specimens were studied. The tumor edge was defined precisely by immunohistochemistry, suggesting a high molecular weight cytokeratin that stains only the basal cells of benign histology. Microvascularity density quantification was performed using von Willebrand factor antigen immunohistochemistry as previously defined. Five parallel arcs were defined along which vessel density was calculated including arcs within, on the edge, and removed from the neoplasm.

RESULTS

In 13 of 14 cases, the highest vessel density was found within the tumor. Significant differences were observed between the edge of the tumor and 2.5 mm within the benign periphery, between the benign and malignant tissue at the border, and between CAP at the edge and CAP 2.0 mm within the neoplasm. These findings suggest a stepwise increase in MVD toward the center of the neoplasm.

CONCLUSIONS

These data confirm the authors' previous observation that prostate cancer has approximately a two-fold increase in MVD compared with the benign tissue. Moreover, high vascularization of the center explains the rare finding of necrosis in CAP. These data suggest that angiogenic promoters may have their highest activity in the center of the neoplasm.

Computerized analysis of transrectal ultrasonography images in the detection of prostate carcinoma

OBJECTIVE

To report on the use of automated image analysis in the interpretation of transrectal ultrasonographic images of the prostate.

PATIENTS AND METHODS

During transrectal ultrasonography, images were recorded from biopsies performed in 127 patients. Subsequently in the image, the puncture place was marked and analysed. Analysis of the images was performed with the Automated Urologic Diagnostic Expert (AUDEX) system, consisting of a personal computer connected to the ultrasound machine. From the images collected, parameters can be calculated for image classification. The parameters obtained with this procedure were correlated with the histological result.

RESULTS

Evaluation showed a sensitivity of 84.8% and specificity of 87.5%. The positive and negative predictive values, to predict prostate carcinoma, were 84.8% and 87.5%, respectively.

CONCLUSION

Automated image analysis can help in the diagnosis of prostate carcinoma. In patients with non-palpable lesions or with poorly visualized tumours, image analysis is superior to the standard current diagnostic techniques.

Carcinoma prostatico: Confronto tra tomografia assiale computerizzata e risonanza magnetica nucleare nella stadiazione locale: Prostatic carcinoma: Comparison between computed tomography and magnetic resonance in local tumour staging

We evaluated 20 patients with prostatic carcinoma who subsequently underwent radical prostatectomy with pelvic lymphadenectomy. All patients were examined with CT scan (CT) and magnetic resonance (MR) and the findings compared with definitive pathological stage. The neoplasia was correctly diagnosed in 19/20 patients with MR, but in no-one with CT. Sensitivity and diagnostic accuracy of CT and MR were respectively: for capsular penetration 15%/20% and 36.8%/40%; for seminal vesicle involvement 20%/60% and 60%/80%; bladder involvement 25%/85% and 50%/90%; nodal involvement 0%/60% and 16.6%/65%. MR seems to be more reliable than CT in detecting seminal vesicle involvement. Nevertheless, neither MR nor CT gave an adequate evaluation of capsular penetration or tumour spread to lymph nodes.

Anatomy of the prostate and distribution of early prostate cancer

Many of the difficulties in understanding diseases of the prostate have arisen through poor understanding of the anatomy of the prostate. The recent description of histologically separate zones in the prostate has been an important advance, allowing evaluation of separate cancers arising in the transition and peripheral zones of the prostate. While the majority of cancers sampled at transurethral resection of the prostate (TURP) are of transition zone origin, most of these prostates contain separate cancers in the peripheral zone. The peripheral zone cancers have a higher grade-to-volume ratio and are more frequently associated with histological features of progression (extracapsular extension, seminal vesicle invasion) than transition zone cancers. Furthermore, peripheral zone cancers are frequently associated with prostatic intraepithelial neoplasia, in contrast to transition zone cancers. These findings suggest a greater biological activity for cancers arising in the peripheral zone. The majority of cancers detected by digital rectal examination are of peripheral zone origin. While associated transition zone cancers are less frequently present than in TURP sampled prostates, a similarly high association of peripheral zone cancers with histological indicators of biological activity is seen. DNA ploidy analysis of separate foci in radical prostatectomy specimens confirms a significantly higher rate of non-diploidy in cancers of peripheral zone origin, some of very small volume, which further suggests a greater biological activity compared to transition zone cancers.

DNA ploidy measurements in prostate cancer: differences between image analysis and flow cytometry and clinical implications

The relationship between DNA ploidy and prognostic parameters has been established in prostate cancer. However, comparison of various techniques used for DNA ploidy analysis has not been sufficiently addressed in prostate carcinoma. In the present study, grossly identified discrete carcinoma foci from 48 consecutive radical prostatectomy specimens were analyzed by flow cytometry and image analysis using both imprints and tissue sections. Correlations with other prognostically important pathological findings such as grade, size, extracapsular extension, positive surgical margin, and seminal vesicle and lymph node involvement were done. Image analysis detected 26 (54.2%) nondiploid tumors compared to 15 (31.3%) nondiploid tumors by flow cytometry. No significant differences were demonstrated between imprints and tissue sections. DNA ploidy status showed a good correlation with most other pathological findings listed above. In conclusion, DNA ploidy status determination gives clinically useful information which correlates well with the other useful pathological parameters of prognostic importance. Image analysis may be more sensitive than flow cytometry in detecting nondiploid populations. Tissue sections appear to be as reliable as imprints when properly controlled.

Influence of initial presentation on treatment outcome of clinically localized prostate cancer treated by definitive radiation therapy

PURPOSE

The increasing proportion of early stage prostate cancer diagnosed by various early detection methods together with reports espousing watchful waiting as a management option raise the possibility that patients may be selected for surveillance according to their initial presentation.

METHODS AND MATERIALS

The outcome for 427 men with clinical stages T1 to T4 localized prostate cancer treated with radiation therapy was evaluated according to their presentation: elevated prostate-specific antigen (PSA) level; abnormal digital rectal examination; or, urologic symptomatology.

RESULTS

With a median follow-up of 30 months, there were no significant differences in disease outcome according to initial presentation. The actuarial incidence of relapse at 5 years was: PSA-detected (54 patients), 24%; digital rectal-detected (173 patients) 29%; and, symptom-detected (200 patients) 31% (p = 0.79). Likewise, there were no significant differences in the incidence of postradiation rising PSA profiles among the three groups. The actuarial incidence of relapse and/or rising PSA at 5 years was: PSA-detected 35%; digital rectal-detected 42%; symptom-detected, 48% (p = 0.72). On the other hand, T-stage, Gleason grade, pretreatment PSA, pretreatment acid phosphatase, and transurethral resection in T3/T4 disease were each highly correlated with outcome. In multivariate proportional hazards regression pretreatment PSA (p = 0.0003), Gleason grade (p = 0.045), and transurethral resection in T3/T4 disease (p = 0.0562) correlated with outcome, but initial presentation did not (p = 0.25).

CONCLUSION

The absence of a prognostic gradient, good to bad, from PSA-detected through digital rectal-detected to symptom-detected cancer suggests that the initial presentation of patients with localized prostate cancer is not a valid basis for selecting watchful waiting vs. initial treatment.

Indications for and the significance of seminal vesicle irradiation during 3D conformal radiotherapy for localized prostate cancer

PURPOSE

To evaluate the use of pretreatment prostate specific antigen, Gleason score, and clinical stage as predictors of the risk of seminal vesicle involvement in patients with clinically localized prostatic cancer, and to determine the impact of excluding the seminal vesicles on the dose received by surrounding normal tissues.

METHODS AND MATERIALS

An empirically derived equation combining the preoperative prostate specific antigen and Gleason score was applied to 188 patients treated with radical prostatectomy, for whom pathologic evaluation of the seminal vesicles was available. High and low risk groups for seminal vesicle involvement were defined using this equation. The observed risks of seminal vesicle involvement was compared to the predicted risk using the preoperative prostate specific antigen, Gleason score or clinical stage alone or using the empirical equation. Dose-volume histograms for five patients treated using six-field conformal radiotherapy were compared including and excluding the seminal vesicles.

RESULTS

Using the empirically derived equation, a low risk group of 109 patients was identified with a calculated risk of seminal vesicle involvement of < or = 13% and an observed incidence of 7.3%. Among the high risk group of 79 patients, which included all patients with a calculated risk > 13%, 37% had seminal vesicle involvement (p < 0.001 low vs. high risk). Twenty percent of the rectal volume received on average above 86% of the total dose for the five plans which included the seminal vesicles compared to 68% for the five plans excluding the seminal vesicles. The doses to 40% of the rectal volume were 64% and 37% if the seminal vesicles were included and excluded, respectively. The dose to the bladder and femoral heads was also decreased but to a lesser extent.

CONCLUSION

The empirical formula predicts risk of seminal vesicle involvement with a higher degree of significance for a larger number of patients than either Gleason score, clinical stage, or prostate specific antigen alone. Based on an analysis of our first 100 patients treated with definitive conformal therapy alone, approximately 47% of those patients could have been treated excluding the seminal vesicles. Excluding the seminal vesicles may allow us to go to a higher total dose with less rectal toxicity.

Seminal vesicle volume as a sonographic predictor of prostate cancer stage

OBJECTIVES

Accurate clinical staging of prostate cancer continues to challenge the urologist, with understaging a common problem. Preoperative identification of men with capsular penetration or seminal vesicle invasion would allow deferment of radical surgery unlikely to cure the patient. We investigated the ability of seminal vesicle volume as determined by transrectal ultrasound (TRUS) to predict the stage of prostate carcinoma.

METHODS

Forty-seven consecutive men undergoing radical prostatectomy had preoperative determination of the seminal vesicle volume by TRUS. The volume was determined for each individual seminal vesicle as well as the total seminal vesicle volume. Asymmetry was defined as one seminal vesicle having twice the volume of the other.

RESULTS

Average total seminal vesicle volume was statistically greater for patients with Stage C disease as opposed to those with organ-confined tumors. Seminal vesicle asymmetry was also present statistically more often in Stage C patients than Stage B men. The combination of total seminal vesicle volume less than 15 cc and symmetrical seminal vesicles yielded a possibility of only 18% of extraprostatic extension of tumor.

CONCLUSIONS

We believe that seminal vesicle volume as determined by TRUS can aid in the staging of adenocarcinoma of the prostate and should be considered along with other parameters, such as prostate-specific antigen, acid phosphatase, and Gleason score, when planning therapy for this disease.

Detection of microscopic extracapsular extension prior to radical prostatectomy for clinically localized prostate cancer

OBJECTIVE

To assess better techniques of clinical staging to identify the presence and location of extracapsular extension (ECE) and assist the surgeon in the selection of candidates for resection or preservation of neurovascular bundles during radical prostatectomy.

PATIENTS AND METHODS

In a retrospective review of the records of 117 patients with clinically localized (31 T1 and 86 T2) prostate cancer treated with radical prostatectomy the results of digital rectal examination (DRE), real-time transrectal ultrasound (TRUS) and a retrospective review of static films were compared to assess their accuracy in the detection of ECE. The ultrasonic criterion for ECE was bulging or irregularity of the boundary echo adjacent to a hypoechoic lesion. On DRE, the criterion for ECE was palpable bulging of a nodule beyond the normal contour of the prostate. The reference standard was the presence and location of ECE in the whole-mount, serially sectioned radical prostatectomy specimens.

RESULTS

Microscopic ECE was present in 64 of the specimens (55%). There was no significant difference between DRE, prospective TRUS and retrospective TRUS in the overall accuracy of detection of ECE. However, when the results of DRE and TRUS were combined (if either was positive the result was considered positive), the positive predictive value (PPV) was 79% and the sensitivity (91%), with the overall accuracy increased significantly (P < 0.05).

CONCLUSION

The presence and precise location of microscopic ECE can be determined pre-operatively with reasonable accuracy using real-time ultrasound combined with the results of DRE.

Analysis of ultrasonographic prostate images for the detection of prostatic carcinoma: the automated urologic diagnostic expert system

This paper describes a study on the automated analysis of ultrasonographic prostate images. With image processing, tissue characterization in the prostate was performed to assess the probability of malignancy. During prostate examinations, images were recorded at the positions where biopsies were taken. The used samples were divided into three groups. Two of them were used for the construction of a classification tree, and the third was used for the evaluation of this classification. A sensitivity of 80.6% and specificity of 77.1% were reached retrospectively. In a prospective way, these results were 80.0% and 88.2%, respectively. The prospective predictive value for cancer detection was 85.7%. The presented prospective value for image analysis was almost twice as high as the values normally found for prostate examination.

Transrectal ultrasonography to assess local extent of prostatic cancer before radical prostatectomy

OBJECTIVE

To evaluate transrectal ultrasonography (TRUS) with a 7 mHz rotating probe as a staging procedure in 33 patients with localized prostatic carcinoma.

PATIENTS AND METHODS

The ultrasound scans were compared to histopathological whole-mount step sections of the surgical specimens. Twenty-five of the patients had tumours with pathological stage T3 (pT3) and eight had tumours with stage pT2 giving a prevalence of extracapsular growth of 0.76.

RESULTS

The overall sensitivity, specificity, positive and negative predictive values for detection of extracapsular tumour growth by TRUS of prostatic cancer were found to be 0.68, 0.63, 0.85 and 0.38, respectively. Six tumours showed solely microscopic foci of extracapsular tumour growth.

CONCLUSION

This technique gives a high percentage of both understaging (32%) and overstaging (37%) and therefore TRUS is an unreliable tool in the staging protocol prior to radical prostatectomy.

The reliability of computer analysis of ultrasonographic prostate images: the influence of inconsistent histopathology

This article describes a method to investigate the influence of inconsistent histopathology during the development of tissue discrimination algorithms. Review of the pathology is performed on the biopsies used as training set of a computer system for cancer detection in ultrasonographic prostate images. The influence of the discrepancies found between independent pathologists on the discriminating power of the system is investigated. A high diagnostic consistency in histopathology concerning only the categories malignant and nonmalignant is found. Therefore, review of the pathology does not significantly influence the results of tissue discrimination algorithms for cancer detection. However a high interobserver variability is obtained in the differentiation between more histology classes.

Selection of patients for laparoscopic pelvic lymphadenectomy prior to radical prostatectomy: a decision analysis

Indications for laparoscopic pelvic lymphadenectomy prior to radical prostatectomy have not been established. Criteria to predict lymph node metastases were derived from the preoperative evaluations of 164 prostate cancer patients undergoing pelvic lymphadenectomy. Decision analysis was used to determine which criteria would be optimal indicators for laparoscopic pelvic lymphadenectomy prior to intended radical prostatectomy. Besides a digital rectal examination suggesting uncontained tumor, which was the best indication for laparoscopic pelvic lymphadenectomy, the most useful criteria were sonographic tumor volume > or = 3 cc and prostate-specific antigen (PSA) > or = 20 ng/mL. If either parameter was met, the sensitivity for identifying patients with pelvic lymph node metastases was 88 percent and the positive predictive value was 42 percent. When both were met, the sensitivity fell to 47 percent but the positive predictive value increased to 67 percent. A combination of Gleason biopsy score and PSA was the best criterion that was independent of transrectal ultrasonography. Using a PSA > or = 15 ng/mL for tumors with Gleason biopsy score > or = 7 or a PSA > or = 25 ng/mL for tumors with a Gleason biopsy score of 5-6 had a sensitivity of 71 percent and positive predictive value of 48 percent for identifying patients with pelvic lymph node metastases. In selecting patients for laparoscopic pelvic lymphadenectomy prior to radical retropubic prostatectomy, criteria with a positive predictive value greater than 39 percent maximize the utility of laparoscopic pelvic lymphadenectomy. Prior to radical perineal prostatectomy, laparoscopic pelvic lymphadenectomy will identify pelvic lymph node metastases that would otherwise be undetected by prostatectomy alone. The sensitivity of selection criteria, therefore, should be increased, as long as the positive predictive value remains above 20 percent.

Ultrasonic detection of non-palpable seminal vesicle invasion: a clinicopathological study

In an effort to identify reliable criteria for detecting seminal vesicle invasion (SVI) with transrectal ultrasonography (TRUS) in patients with clinically localised prostate cancer, we reviewed the pre-operative sonograms in 230 patients who underwent radical retropubic prostatectomy; 49 patients (21%) had pathologically confirmed SVI. Conventional sonographic criteria for SVI (asymmetry, distension, atrophy, abnormal echogenicity and irregularity in outline) were present in 58 patients, but only 16 (28%) had pathologically confirmed SVI. On the basis of the results of a preliminary comparison of radical prostatectomy specimens and TRUS, we had revised our criteria for the recognition of SVI: (1) a hypoechoic lesion at the base of the prostate (within 10 mm of the seminal vesicle); (2) an "adhesion sign" resulting from the loss of the echo reflections from the normal fat plane between the prostate and the seminal vesicle; (3) "posterior convexity" of the seminal vesicles. When we reviewed the 230 sonograms retrospectively, we found a hypoechoic tumour at the base in 70 patients, of whom 37 had SVI (positive predictive value (PPV) 53%). An adhesion sign was found in 16 patients, 12 of whom had SVI (PPV 75%). Posterior convexity was present in 4 patients, all of whom had SVI. If any one of our sonographic signs was present, the overall accuracy (83%), sensitivity (90%) and positive predictive value (51%) were significantly better than with any one of the conventional criteria. Patients with SVI were also more likely to have a high serum prostate specific antigen (PSA) level. The PPV for SVI of a PSA level > or = 10 ng/ml was 38%. If the PSA was > 10 ng/ml and TRUS was positive (> or = 1 of our sonographic criteria), 16 (62%) of 26 patients had SVI. If the PSA was < 10 ng/ml and TRUS was negative, only 3 (3%) of 86 patients had SVI. It was concluded that the conventional criteria for detecting SVI on ultrasonography are not accurate in patients with early stage prostate cancer. There are, however, reliable criteria that predict SVI with reasonable accuracy and these criteria, combined with the serum PSA levels, can stratify patients into those with a low risk and those with a high risk of SVI.

Use of endorectal surface coil magnetic resonance imaging for local staging of prostate cancer

A total of 111 patients with clinically localized prostate cancer (stage A or B) underwent endorectal surface coil magnetic resonance imaging (MRI) for preoperative staging of the disease. Of the patients 43 with advanced disease on endorectal surface coil MRI (33 with stage C and 10 with stage D disease) received alternative therapy, as did 21 with stage B disease on MRI. The overall staging accuracy for the remaining 47 patients was 68%, with a 74% accuracy rate in staging advanced disease and a 91% accuracy rate for depiction of seminal vesicle involvement. Failure to recognize microscopic extracapsular disease was responsible for the majority of staging inaccuracies in this highly select group of patients. Endorectal surface coil MRI provides extremely high resolution images of the prostate and periprostatic structures, and is an exciting new modality for local staging of prostatic carcinoma.

Combined role of transrectal ultrasonography, Gleason score, and prostate-specific antigen in predicting organ-confined prostate cancer

Prostate cancer staging is frequently inaccurate. By combining transrectal ultrasonography (TRUS) with a retrospectively derived grade-stratified prostate-specific antigen (PSA-GS) scale, we demonstrated 77 percent staging accuracy in 155 men with clinically localized prostate cancer undergoing radical prostatectomy. When used as the first step in a staging algorithm, PSA-GS (Score > or = 7: PSA > or = 4.0 ng/mL, uncontained; Score = 5 or 6: PSA > or = 8.0 ng/mL, uncontained; Score < or = 4: PSA > or = 16.0 ng/mL, uncontained) had a sensitivity of 75 percent and a specificity of 72 percent. The addition of TRUS to the staging algorithm, necessary only in patients with negative predictions by PSA-GS (46%), increased the sensitivity to 86 percent and the negative predictive value to 79 percent, while positive predictive value was unchanged at 77 percent. The combination of TRUS with PSA < 4 ng/mL or > or = 16 ng/mL identified subsets of patients with 85 percent and 88 percent likelihood of contained and uncontained disease, respectively. Our algorithm minimizes operator dependency by requiring TRUS in less than half of the patients. It produced improved staging, but the overall results were inaccurate in 23 percent of patients. Further refinements in prostate cancer staging are still necessary.

Value of transrectal ultrasound in identifying local disease after radical prostatectomy

Transrectal ultrasound was performed on 15 men with clinical suspicion of local disease after radical retropubic prostatectomy. Clinical suspicion was defined as an elevation in serial serum prostate-specific antigen (PSA, above 0.4 ng/mL, Tandem-R + Assay) and/or palpable mass in the rectal vault. Post-radical prostatectomy ultrasound was normal if there was smooth tapering of the bladder neck to the urethra with no foci of variable echogenicity, and suspicious if any hyper- or hypo-echoic foci were present or if a mass was detected. Thirteen of 15 ultrasounds (87%) were described as suspicious while 2 of 15 (13%) were described as normal. Only 6 of 13 patients (46%) with suspicious findings on ultrasound had biopsy-proved carcinoma. Both patients with normal findings on post-radical prostatectomy ultrasound had biopsy-proved cancer. Transrectal ultrasound of the prostatic fossa when used independently is of no value in the diagnosis of local disease after radical prostatectomy. Transrectal ultrasound may help to direct systematic biopsies of the prostatic fossa in those patients in whom local disease is suspected on the basis of elevated serum PSA and/or a mass found on rectal examination.

Comparison of the pathologic features and DNA ploidy value of prostate cancers detectable by sonography and by palpation

Ultrasonography of the prostate detects some cancers that are not palpable, but the pathologic features of such cancers have not been well described. Since screening trials consistently find sonography more sensitive (though less specific) than digital rectal examination, nonpalpable cancers that are visible as hypoechoic lesions on ultrasound have been postulated to be early cancers of limited malignant potential and may not require aggressive treatment. To test this hypothesis, we determined the pathologic features and DNA ploidy value of prostate cancers in 63 radical prostatectomy specimens taken from patients with clinical stage T1 (n = 28) and T2 (n = 35) prostate cancer. In 40 patients (63%), the cancer appeared hypoechoic on ultrasound. The median volume of these cancers was 4.19 cm3 (range 0.45-19.22); 80% exhibited extra-capsular extension (ECE); 30% had seminal vesicle invasion (SVI); and 95% were nondiploid by nuclear image analysis (CAS 200 system). In patients with isoechoic cancer, tumor volume was significantly less (median 0.38 cm3) and ECE and SVI occurred less frequently (13% and 0%, respectively). Only seven (30%) had nondiploid tumors. In 35 patients, the tumor was palpable, and the pathologic features and DNA ploidy values (94% nondiploid) of these cancers were similar to those of the tumors that were visible on ultrasound. In seven patients, the cancer was visible by ultrasound but not palpable by digital rectal examination. Median tumor volume was 1.72 cm3 (range 0.45-18.98); four patients (57%) had ECE; one (14%) had SVI, and six (86%) had nondiploid cancers. We conclude that most cancers that appear hypoechoic on ultrasound are clinically important and exhibit aggressive pathologic features. Palpable cancers and sonographically visible cancers are similar and should be staged and treated similarly.

Frequency and location of extracapsular extension and positive surgical margins in radical prostatectomy specimens

Positive surgical margins have been reported with disturbing frequency in radical prostatectomy specimens and may portend an increased risk of eventual treatment failure. We determined the location of any cancer, extracapsular extension and positive surgical margins in 144 consecutive step-sectioned radical prostatectomy specimens. Of the 46 stage A cancer patients 98% had residual cancer in the prostate after transurethral resection and in 76% cancer was found posteriorly in the gland. Extracapsular extension was identified in 10 patients (22%): anteriorly in 5, posterolaterally in 5 and on the most apical transverse section in 4. Positive margins were found in 10 patients (22%) and half of these occurred posterolaterally. Of the 98 stage B cancer patients tumor was located posteriorly in 97%. Extracapsular extension was found in 62 patients (63%) and in 87% of these it was located posterolaterally. Positive margins were found in 23%, most commonly in the posterolateral and rectal areas (57% and 26%, respectively), and in more than half of these the positive margin resulted from incision into the capsule. In 18 of the 144 patients (13%) a single positive surgical margin was the only pathological indicator of treatment failure and half of these occurred in the area of the neurovascular bundle. Some of these patients with extraprostatic tumor might have been cured if wide excision of the neurovascular bundle had been performed. Overemphasis on preservation of potency during radical prostatectomy may leave some patients with persistent local disease.

Early detection of prostate cancer

Prostate cancer is unique among the potentially lethal human malignancies in the wide discrepancy between the high prevalence of histologic changes recognizable as cancer and the much lower prevalence of the clinical disease. Despite the availability of effective tests for early detection and of effective treatment for cancers so detected, the diagnosis usually is not established until the tumor is locally advanced or metastatic. Yet, physicians hesitate to use these tests for fear that many cancers found would be latent, of little threat to the life or health of the host, and treatment could introduce inappropriate morbidity. Latent or "clinically unimportant" cancers can be distinguished from those that are clinically important by the larger volume, higher grade, and greater invasiveness of the latter. The available tests can detect only those cancers large enough to be palpable, visible on ultrasound, or capable of elevating the serum level of prostate-specific antigen. Such cancers are clinically important and should be treated for cure if the life expectancy of the patient is sufficiently long and the morbidity rate of therapy is low. Early detection of prostate cancer using the tests that are available today may widen the window of opportunity so that treatment indeed becomes possible in those for whom it is necessary.

Unusual hyperechoic appearance of prostate cancer on transrectal ultrasonography

A series of 157 patients with prostate cancer underwent transrectal ultrasonography prior to radical prostatectomy. In 112 patients (71.3%) the tumours appeared hypoechoic relative to the echo pattern of the normal peripheral zone; in 43 (27.4%) they appeared isoechoic, and in only 2 (1.3%) did they appear purely or predominantly hyperechoic. These 2 hyperechoic tumours were unusual ductal adenocarcinomas with central necrosis and dystrophic calcification within solid tumour nests, a pattern similar to that of comedo-carcinoma of the breast. Calcification within prostate cancer was found in 4 of the 157 radical prostatectomy specimens, including 2 other hypoechoic cancers which contained intraluminal or psammomatous calcification. Although the most common sonographic appearance of localised prostate cancer is hypoechoic, a predominantly hyperechoic pattern is seen occasionally and suggests the presence of a high grade ductal adenocarcinoma.

Local staging of prostate cancer with transrectal ultrasound: a literature review

A literature review was undertaken to investigate whether transrectal ultrasound can predict the local stage of prostate cancer. Twelve papers were found which correlated ultrasound findings with surgical findings and another paper reported on strategic staging biopsies guided by transrectal ultrasound. Eleven of these papers reported on ultrasound findings in patients in whom digital rectal examination had defined localized disease. One paper compared ultrasound findings and digital rectal findings. One paper indicated that transrectal ultrasound, though not suited to patients with clinically localized disease defined by digital rectal examination, may be superior as the initial staging tool. We conclude that transrectal ultrasound has too low a specificity to upgrade the diagnostic results of digital rectal examination, but that it may be more useful as the primary staging tool and for guidance in strategic staging biopsies.

Transrectal ultrasonography in the staging of localized prostatic carcinoma. A pilot study

Transrectal ultrasonography (TRUS) was evaluated as a staging procedure in ten patients with localized prostatic carcinoma. The ultrasound images were correlated to histopathological whole-mount step sections of the surgical specimens after radical prostatectomy. Nine of the patients had pathological stage T3 (pT3) and only one was pT2. TRUS gave a diagnostic accuracy of 60% compared to 10% both for digital rectal examination (DRE) and computer tomography (CT) in detecting extracapsular tumor spread. We conclude so far that TRUS is superior to DRE and CT in detecting extracapsular tumor spread. Further we state that whole-mount step section of the surgical specimens is mandatory in order to achieve a correct pathological staging (pT-stage).

Radiotherapy for prostate cancer: should the seminal vesicles be considered target?

During radiotherapy for prostate cancer, the ability to predict occult seminal vesicle invasion is important since irradiation of the entire seminal vesicles necessitates enlarging the radiation fields beyond what is usually used to irradiate the prostate gland alone. We analyzed the records of 302 patients with clinical Stage T1 or T2 adenocarcinoma of the prostate treated with radical surgery at Duke University Medical Center between 1970 and 1983. Univariate and multivariate analyses were used to examine the relationship between the risk of occult seminal vesicle involvement (defined herein as histologic involvement of the seminal vesicles not detected by physical or radiologic examination) and the following factors: histologic grade, age, clinical stage, and preoperative acid phosphatase. Among 249 patients with complete information, increasing histologic grade (p < 0.001) and clinical stage (p < 0.04) were found to be the strongest predictors of occult seminal vesicle invasion. Conversely, seminal vesicle invasion was very unusual in well-differentiated T1-T2 tumors (6%). This low risk group represented 28% (70/249) of this patient population. There appears to be a substantial subset of patients with well differentiated T1 or T2 tumors who are at very low risk for occult seminal vesicle involvement and in whom the seminal vesicles can be excluded from the target volume. The reduction in target volume may reduce normal tissue reactions, facilitate dose escalation, and possibly increase local control rates.

Relationship between clinical stage and histological zone of origin in early prostate cancer: morphometric analysis

A detailed morphometric analysis of 96 radical prostatectomy specimens (13 clinical stage A1, 29 A2, 34 B1 and 20 B2) was undertaken to examine the relationship of zone of origin to volume, grade and extraprostatic extension of cancer. In patients with stage A disease, transition zone (TZ) cancer (present in 81%) was significantly larger but of lower grade than peripheral zone (PZ) cancer (present in 90%). The total volume of cancer in stage A1 patients averaged 1.55 ml with 72% of TZ origin. In patients with stage A2 disease, tumour volume averaged 5.83 ml with only 57% of TZ origin. Specimens taken during transurethral resection of the prostate (TURP) revealed TZ cancer in 82% and PZ cancer either alone or with TZ cancer in 22%. The 9 patients with PZ cancer in the TURP specimen included 5 of the 11 with extracapsular extension and all 5 of those with seminal vesicle invasion. Every patient with stage B disease had PZ cancer which, in all except 3 cases, was of significantly larger volume and higher grade than any TZ cancer (present in 43%) in the same gland. In patients with stage B cancer, total tumour volume was 5.13 ml with 91% of PZ origin. TZ cancer tended to be well differentiated in all patients, even at large volumes, whereas PZ cancer was often moderately or poorly differentiated even at low volumes. In patients with stage B disease, TZ cancer appeared to be incidental and of no clinical importance, while in stage A patients PZ cancers were sometimes large, poorly differentiated and extended outside the prostate. Progression of a stage A cancer seems more likely to result from PZ cancer than TZ cancer, and the finding of PZ cancer in a TURP specimen should probably preclude its classification as stage A1.

The effect of local control on metastatic dissemination in carcinoma of the prostate: long-term results in patients treated with 125I implantation

The study evaluates the effect of the locally recurring tumor on the incidence of metastatic disease in early stage carcinoma of the prostate. The probability of distant metastases was studied in 679 patients with Stage B-C/N0 carcinoma of the prostate treated at MSKCC between 1970 and 1985 (median follow-up of 97 months). Patients were staged with pelvic lymph node dissection and treated with retropubic 125I implantation. The actuarial distant metastases free survival (DMFS) for patients at risk at 15 years after initial therapy was 37%. Cox proportional hazard regression analysis of covariates affecting the metastatic outcome showed that local failure, used in the model as a time dependent variable, was the most significant covariate, although stage, grade, and implant volume were also found to be independent variables. The relative risk of metastatic spread subsequent to local failure was 4-fold increased compared to the risk without evidence of local relapse. The 15-year actuarial DMFS in 351 patients with local control was 77% compared to 24% in 328 patients who developed local relapses (p less than 0.00001). The relation of distant spread to the local outcome was observed regardless of stage, grade, or implant dose. Even stage B1/N0-Grade I patient with local control showed a 15-year actuarial DMFS of 82%, compared to 22% in patients with local relapse; p less than 0.00001). The median local relapse-free survival (LRFS) in the 268 patients with local recurrences who did not receive hormonal therapy before distant metastases were detected was 51 months, compared to a median of 71 months for DMFS in the same patients (p less than 0.001), consistent with the possibility that distant dissemination may develop secondary to local failure. Furthermore, distant metastases in patients with local control, apparently already existing as micrometastases before treatment, were detected earlier (median DMFS of 37 months) than in patients with local relapse (median DMFS of 54 months; p = 0.009). These data suggest that the existence and re-growth of local residual disease in localized prostatic carcinoma promotes an enhanced spread of metastatic disease, and that early and complete eradication of the primary tumor is required if a long term cure is to be achieved, although the clinical expression of secondary metastases may not become apparent for 6.5 years or more in one-half of the patients.