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

When to biopsy seminal vesicles

OBJECTIVES

The involvement of seminal vesicles in prostate cancer can affect the prognosis and determine the treatment. The objective of this study was to determine whether we could predict its infiltration at the time of the prostate biopsy to know when to indicate the biopsy of the seminal vesicles.

MATERIAL AND METHODS

observational retrospective study of 466 patients who underwent seminal vesicle biopsy. The indication for this biopsy was a prostate-specific antigen (PSA) level greater than 10 ng/ml or an asymmetric or obliterated prostatoseminal angle. The following variables were included in the analysis: PSA level, PSA density, prostate volume, number of cores biopsied, suspicious rectal examination, and preservation of the prostatoseminal angle, studying its relationship with the involvement of the seminal vesicles.

RESULTS

Forty-one patients (8.8%) had infiltrated seminal vesicles and 425 (91.2%) had no involvement. In the univariate analysis, the cases with infiltration had a higher mean PSA level (P < .01) and PSA density (P < .01), as well as a lower mean prostate volume (P < .01). A suspicious rectal examination (20.7% of the infiltrated vesicles) and the obliteration or asymmetry of the prostatoseminal angle (33.3% of the infiltrated vesicles) were significantly related to the involvement (P < .01). In the multivariate analysis, we concluded that the probability of having infiltrated seminal vesicles is 5.19 times higher if the prostatoseminal angle is not preserved (P < .01), 4.65 times higher for PSA levels >19.60 ng/dL (P < .01) and 2.95 times higher if there is a suspicious rectal examination (P = .014). Furthermore, this probability increases by 1.04 times for each unit of prostate volume lower (P < .01). The ROC curves showed maximum sensitivity and specificity at 19.6 ng/mL for PSA and 0.39 for PSA density.

CONCLUSIONS

In this series, greater involvement of seminal vesicles was associated with a PSA level ≥20 ng/ml, a suspicious rectal examination and a lack of prostatoseminal angle preservation.

Imaging in prostate cancer staging: present role and future perspectives

Despite recent improvements in detection and treatment, prostate cancer continues to be the most common malignancy and the second leading cause of cancer-related mortality. Thus, although survival rate continues to improve, prostate cancer remains a compelling medical health problem. The major goal of prostate cancer imaging in the next decade will be more accurate disease characterization through the synthesis of anatomic, functional, and molecular imaging information in order to plan the most appropriate therapeutic strategy. No consensus exists regarding the use of imaging for evaluating primary prostate cancer. However, conventional and functional imaging are expanding their role in detection and local staging and, moreover, functional imaging is becoming of great importance in oncologic management and monitoring of therapy response. This review presents a multidisciplinary perspective on the role of conventional and functional imaging methods in prostate cancer staging.

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.

Complete Resection of Seminal Vesicles at Radical Prostatectomy Results in Substantial Long-Term Disease-Free Survival: Multi-institutional Study of 6740 Patients

OBJECTIVES

To estimate the disease-specific survival of patients with complete removal of the seminal vesicles (SVs) at radical prostatectomy and to develop a nomogram for the prediction of SV invasion (SVI).

METHODS

An analysis of 6740 patients from three institutions was performed. The primary outcome was biochemical failure analyzed according to the presence or absence of SVI using the Kaplan-Meier method and Cox proportional hazards model. The variables analyzed included age, biopsy Gleason score, clinical T stage, margin status, extracapsular extension, SVI, surgical Gleason score, initial prostate-specific antigen level, and institution. Logistic regression analysis was used to determine the preoperative factors predicting for SVI and create the model for the nomogram.

RESULTS

Of the 6740 patients, 566 (8.4%) had positive SVs. The median follow-up was 33.4 months (range 1 to 239). The 5 and 10-year biochemical relapse-free survival rate was 38.0% and 25.6%, respectively, for patients with positive SVs and 85.7% and 77.2%, respectively, for patients with negative SVs (P <0.0001). In the multivariate model, all variables, except for biopsy Gleason score and T stage, were significant predictors of biochemical failure (P <0.05), and all variables, except for age, were predictors of SVI. The nomogram achieved an area under the curve of 0.80.

CONCLUSIONS

These results have demonstrated that a substantial number of patients with SVI are disease free at 5 and 10 years after complete excision without adjuvant therapy. These findings suggest the therapeutic efficacy of complete SV excision and can identify those with a nomogram-predicted increased risk of SVI who might benefit from complete excision.

Predictors of seminal vesicle invasion before radical prostatectomy

AIM

To predict whether or not seminal vesicle invasion is present before radical prostatectomy, the relationships between clinical parameters and seminal vesicle invasion were analyzed.

METHODS

A review was conducted of 187 patients who had been clinically diagnosed with stages A(2), B(0), B(1), B(2) or C prostate cancer and who had undergone radical prostatectomy without neoadjuvant therapy. The parameters analyzed for potential predictors of seminal vesicle invasion before radical prostatectomy included age, clinical stage, serum prostate-specific antigen (PSA) level at biopsy, tumor differentiation of biopsy specimens and percentage of cancer positive cores by biopsy. For percentage of cancer positive cores by biopsy, 143 of 187 patients who underwent transrectal sextant biopsy or more than six transrectal ultrasound guided core biopsies were evaluated. These parameters were subjected to univariate and multivariate logistic regression analyses to identify predictors for seminal vesicle invasion.

RESULTS

The median age was 66.8 years (range 51-77 years). Of 187 patients, 27 (14.4%) had seminal vesicle invasion confirmed pathologically. There were significant differences in all parameters except for age between patients with positive and negative seminal vesicle invasion on univariate analysis. Multivariate analysis revealed that serum PSA level, tumor differentiation of biopsy specimens and percentage of cancer positive cores were significant independent predictors of seminal vesicle invasion.

CONCLUSIONS

The results showed serum PSA level, tumor differentiation of biopsy specimens and percentage of cancer positive cores by biopsy before radical prostatectomy may be useful predictors for seminal vesicle invasion.

Endorectal MR Imaging in the Evaluation of Seminal Vesicle Invasion: Diagnostic Accuracy and Multivariate Feature Analysis

PURPOSE

To retrospectively determine the accuracy of endorectal magnetic resonance (MR) imaging in demonstrating seminal vesicle invasion (SVI) and to investigate the MR imaging features that can predict SVI.

MATERIALS AND METHODS

The Institutional Review Board granted exempt status for this retrospective study, with waiver of informed consent; patient data were collected and handled in accordance with HIPAA regulations. Fifty-one men (age range, 44-73 years) with SVI and 303 men (age range, 40-76 years) without SVI who underwent endorectal MR imaging before radical prostatectomy between January 2000 and October 2004 were included in the study. Endorectal MR images were retrospectively and independently analyzed by two radiologists for SVI, tumor at prostate base, extracapsular extension, and other features considered indicative of SVI. Areas under the receiver operating characteristic curves (AUCs) were used to assess the accuracy of detecting SVI at endorectal MR imaging. A multiple logistic regression was used to explore the combinations of MR imaging features that might facilitate the detection of SVI.

RESULTS

Readers 1 and 2 had an AUC of 0.93 and 0.81, respectively, for the detection of SVI. For both readers, the features that had the highest sensitivity and specificity were low signal intensity within the seminal vesicle and lack of preservation of seminal vesicle architecture. At multiple regression analysis, tumor at the prostate base that extended beyond the capsule and low signal intensity within a seminal vesicle that has lost its normal architecture were highly predictive of SVI.

CONCLUSION

Endorectal MR imaging is accurate in demonstrating SVI prior to radical prostatectomy, and recognition of the most predictive features may facilitate the use of this modality.

Preoperative parameters, including percent positive biopsy, in predicting seminal vesicle involvement in patients with prostate cancer

PURPOSE

Complete dissection of the SVs during RP can contribute to increased morbidity including erectile dysfunction and incontinence. Therefore we evaluated the clinical parameters associated with a positive SV finding on final pathology and identified those patients with a minimal risk of SV involvement for potential SV sparing surgery.

MATERIALS AND METHODS

We retrospectively reviewed our RP database from 1991 to 1999 to evaluate the incidence and clinical correlates of SV invasion. Variables studied included preoperative total serum PSA, percent positive biopsy cores, DRE and biopsy Gleason score. Statistical analysis included univariate, multivariate regression analysis and ROC curves.

RESULTS

Of our 1,056 patients 79 (7.4%) had SV involvement. Of the 356 patients with less than 17% positive biopsies, only 2 (0.5%) had SV involvement on final pathology. Preoperative PSA, biopsy Gleason score and percent positive biopsies were all highly predictive of SV invasion on multivariate analysis. Percent positive biopsy was found to be the single best predictor of seminal vesicle invasion (p <0.0001).

CONCLUSIONS

In our series percent positive biopsy was the single best predictor of SV invasion at the time of RP. An analysis of preoperative parameters including percent positive biopsy, biopsy Gleason score and preoperative PSA may define a subset of patients in which prospective studies could be used to determine the value and safety of SV sparing surgery.

A nomogram to predict seminal vesicle invasion by the extent and location of cancer in systematic biopsy results

PURPOSE

We determined whether systematic biopsy results increases the accuracy of standard clinical information in predicting seminal vesicle invasion (SVI).

MATERIALS AND METHODS

We analyzed a retrospective cohort of 763 patients with clinical stages T1c-T3 prostate cancer who were diagnosed by systematic biopsy and treated with radical prostatectomy. We recorded the location of each biopsy core and measured the length of cancer and total length of each core. Using logistic regression analysis we constructed and internally validated a nomogram to predict SVI.

RESULTS

A total of 60 patients (7.9%) had SVI. Cancer was present in a biopsy core from the base in 437 patients, of whom 12.8% had SVI compared with only 1.2% of the 326 without cancer at the base. None of the 275 patients with prostate specific antigen (PSA) 10 ng/ml or less and no cancer at the base had SVI. On multivariate analysis serum PSA (p <0.0005), primary Gleason grade (p = 0.028) and percent cancer at the base (p <0.005) were the only significant predictors of SVI. The predictive accuracy of a standard model that included only stage, grade and PSA was maximally enhanced by including the percent cancer at the base (p = 0.0013). A nomogram that incorporated this variable produced probabilities of SVI that differed from the standard model by +/- 10% in 68% of the cases.

CONCLUSIONS

The presence and amount of cancer in systematic needle biopsy cores from the base of the prostate strongly predicts the presence of SVI. Systematic biopsy results enhance the accuracy of nomograms to predict SVI.

Introducing a prognostic score for pretherapeutic assessment of seminal vesicle invasion in patients with clinically localized prostate cancer

PURPOSE

To identify prostate cancer patients who will have the most likely benefit from sparing the seminal vesicles during 3D conformal radiation therapy.

METHODS AND MATERIALS

From 1988 to 2001, 532 patients underwent radical prostatectomy for clinically localized prostate cancer. Primary endpoint was the pathological evidence of seminal vesicle invasion. Variables for univariate and multivariate analyses were age, prostate weight, clinical stage, PSA level, Gleason score, number and site of positive prostate sextant biopsies. Multivariate logistic regression with backward stepwise variable selection was used to identify a set of independent predictors of seminal vesicle invasion, and the variable selection procedure was validated by non-parametric bootstrap.

RESULTS

Seminal vesicle invasion was reported in 14% of the cases. In univariate analysis, all variables except age and prostate weight were predictors of seminal vesicle invasion. In multivariate analysis, only the number of positive biopsies (P<0.0001), Gleason score (P<0.007) and PSA (P<0.0001) were predictors for seminal vesicles invasion. Based on the multivariate model, we were able to develop a prognostic score for seminal vesicle invasion, which allowed us to discriminate two patient groups: A group with low risk of seminal vesicles invasion (5.7%), and the second with a higher risk of seminal vesicles invasion (32.7%).

CONCLUSIONS

Using the number of positive biopsies, Gleason score and PSA, it is possible to identify patients with low risk of seminal vesicles invasion. In this population, seminal vesicles might be excluded as a target volume in radiation therapy of prostate cancer.

Do impalpable stage T1c prostate cancers visible on ultrasound differ from those not visible?

PURPOSE

We assessed whether the appearance of cancer within the prostate on sonography is associated with different pathological features and/or prognoses compared with nonvisible impalpable cancers defined as stage T1c by the TNM staging system.

MATERIALS AND METHODS

We analyzed the clinical and pathological features, and progression rate in 323 patients with clinical stage T1cNX M0 cancer treated with radical prostatectomy between 1983 and 1998. Mean followup was 46.8 months (range 1 to 186).

RESULTS

Of 323 impalpable stage T1c cancers 170 (53%) were visible and the remainder was not visible on ultrasound. There were no significant differences in clinical or pathological features of the cancers in these 2 groups. The prostate specific antigen nonprogression rate at 5 years was also similar for patients with impalpable cancer regardless of whether the lesion was or was not revealed by ultrasound (mean +/- SE 87% +/- 6% and 91% +/- 6%, respectively, p = 0.3767). Of the 170 visible cancers 55 patients had a hypoechoic lesion considered highly suspicious for cancer. These cancers were higher grade, more extensive, less likely to be confined to the prostate and the prognosis was significantly worse than that of impalpable cancer whether or not they were visible at a less suspicious level (IV or less, p = 0.011). However, such highly suspicious visible cancers are rarely visualized today. Initial serum prostate specific antigen more accurately predicts the pathological stage of impalpable cancer than transrectal ultrasound results.

CONCLUSIONS

Impalpable cancers currently detected have similar pathological features and prognoses whether or not they are visible by ultrasound. Therefore, it is reasonable to categorize impalpable cancers as stage T1c and analyze the response to treatment regardless of the results of ultrasound.

Use of systematic biopsy results to predict pathologic stage in patients with clinically localized prostate cancer: a preliminary report

BACKGROUND

The purpose of this study was to determine the ability of clinical tests to predict advanced pathologic stage (seminal vesicle invasion, pT3c, or pelvic lymph node metastases, pN+).

METHODS

T stage, PSA, PSA density, and pathologic features in systematic biopsy specimens were correlated with pathologic stage in 190 consecutive patients with clinically localized (T1-3) prostate cancer detected by systematic needle biopsies and treated with radical prostatectomies.

RESULTS

Thirty-three patients (17%) had an advanced pathologic stage cancer (pT3c or pN+). In logistic regression analysis, the total length of cancer in all biopsy cores (P < 0.0005), the percent of poorly-differentiated cancer in each specimen (P< 0.021), and serum PSA (P< 0.028) were the only significant predictors of advanced stage. A model was constructed to predict advanced stage: if the PSA was > or = 6 ng/mL and 4 or more biopsy cores were positive and the total length of cancer in all cores was > or = 20 mm and at least 10% of the cancer was poorly-differentiated, then 14 (93%) of 15 patients had an advanced pathologic stage cancer compared to 11% of the remaining 175 patients (P < 0.0005).

CONCLUSION

The pathologic features of cancer in systematic needle biopsy specimens more accurately predicts which patients have advanced stage cancer than standard clinical tests alone.

Stage T1c prostate cancer: defining the appropriate staging evaluation and the role for pelvic lymphadenectomy

A good staging system should be able to accurately reflect the natural history of a malignant disease, to express the extent of the disease at the time of diagnosis, and stratify patients in prognostically distinctive groups. The staging system for prostate cancer, as it is today, fails to fulfill these requirements. Approximately one third of the patients who undergo surgery for complete excision of prostate cancer in fact do not have a localize disease. The incidence of tumor at the inked margin may reach 30% for T1 stage and up to 60% for clinical T2b prostate cancer according to comparison with pathologic examination of resected specimen. Several concepts have been recently proposed as a means of improving the accuracy of the available staging system. In this paper, we review current aspects of clinical and pathological staging of prostate cancer, and the importance of these new concepts on the early stages of prostate cancer.

Use of prostate-specific antigen, Gleason score, and digital rectal examination in staging patients with newly diagnosed prostate cancer

CT Scan, MR Imaging Scan, and Pedal Lymphangiography. Patients with a PSA greater than 25 ng/mL, a Gleason score greater than 6, and a positive DRE should undergo CT scan with FNA of lymph nodes at least 6 mm in size. Otherwise, CT scan, MR imaging scan, and pelvic lymphangiogram are not indicated. This should eliminate use of these staging studies in over 90% of patients with newly diagnosed adenocarcinoma of the prostate. Pelvic Lymph-Node Dissection. Pelvic lymph-node dissection can be safely eliminated in patients who meet the following predictive criteria: 1. PSA not more than 5 ng/mL or 2. Gleason score not more than 5 or 3. A combination of the following: PSA not more than 25 ng/mL, Gleason score not more than 7, and negative DRE. Following these criteria should eliminate the need for pelvic lymphadenectomy in 60% of patients with newly diagnosed prostate cancer.

The role of transrectal ultrasound-guided biopsy-based staging, preoperative serum prostate-specific antigen, and biopsy Gleason score in prediction of final pathologic diagnosis in prostate cancer

OBJECTIVES

To evaluate the role of ultra sound-guided systematic and lesion-directed biopsies, biopsy gleason score, preoperative serum prostate-specific antigen (PSA) as three objective and reproducible variables to provide a reliable combination in preoperative identification of risk of extraprostatic extension in patients with clinically localized prostate cancer.

METHODS

The case records of 813 patients who underwent radical prostatectomy for clinically localized prostate cancer were analyzed. All had multiple systematic biopsies, two to three from each lobe, in addition to lesion-directed biopsies. Additionally, biopsies were done on seminal vesicles (SVs), if abnormal. Based on biopsy results, patients were classified as having stage B1 (T2a-T2b) or B2 (T2c) disease, depending on whether biopsies from one or both lobes were positive and stage C (T3) if there was evidence of SV involvement by biopsy of biopsies from areas of extracapsular extension as seen on transrectal ultrasound (TRUS) were positive. Logistic regression analyses with log likelihood chi-square test was used to define the correlation between individual as well as combination of preoperative variables and pathologic stage.

RESULTS

On final pathologic examination, 473 (58%) patients had organ-confined disease, 188 (23%) had extracapsular extension (ECE), with or without positive surgical margins, and 72 (9%) had SV involvement. Eighty (10%) patients had pelvic lymph node metastases. Biopsy-based staging was superior to clinical staging in predicting final pathologic diagnosis. Logistic regression analyses revealed that the combination of biopsy-based stage, preoperative serum PSA, and biopsy Gleason score provided the best prediction of final pathologic stage. Probability plots constructed with these data can provide significant information on risk of extraprostatic extension in individual patients.

CONCLUSIONS

This study demonstrates that TRUS-guided systematic biopsy in combination with preoperative serum PSA and biopsy Gleason score may provide a cost-effective approach for management decisions and prognostication in patients with prostate cancer.

The New American Joint Committee on Cancer and International Union Against Cancer TNM classification of prostate cancer. Clinicopathologic correlations

BACKGROUND

The 1992 American Joint Committee on Cancer and International Union Against Cancer TNM classification system for prostate cancer includes categories for the increasingly common nonpalpable cancers detected by serum prostate specific antigen (PSA) levels and transrectal ultrasonography (TRUS), but few details have been published about the pathologic features and prognosis of such cancers.

METHODS

We analyzed the clinical and pathologic features of 400 patients with clinical Stages T1-T3, NO or NX, M0 cancer treated with radical prostatectomy. We compared volume, grade, extension, and prognosis of cancers detected by PSA or TRUS to those detected by the traditional techniques of transurethral resection (TURP) or digital rectal examination.

RESULTS

As clinical stage increased in the TNM classification, the volume, grade, and frequency of extraprostatic spread increased significantly. The 33 nonpalpable, nonvisible tumors detected because of an elevated PSA (T1c) were similar in size and frequency of extension to TURP-detected (T1a-b) cancers, but more often were poorly differentiated (52% vs. 22%) (P < 0.03). No T1c cancer has recurred to date. Nonpalpable T2 cancers detected by TRUS (n = 42) were significantly more likely (47% vs. 18%) to extend outside the prostate than were T1c cancers. Compared to palpable T2 cancers, TRUS-detected T2 cancers were smaller but were similar in grade, extension, and prognosis. T3 cancers were extensive and recurred rapidly; only 6% were confined to the prostate. In contrast, 24% of the T1 and 57% of the T2 cancers were not confined (> or = pT3), but only 6-9% of T1-T2a cancers exhibited advanced pathologic features (seminal vesicle invasion or lymph node metastases), compared with 26% of the T2b-c cancers.

CONCLUSION

The new TNM staging system provides appropriate new categories for inclusion of nonpalpable cancers detected by PSA and ultrasound. This new classification is logical and generally reflects the pathologic extent and prognosis of these tumors, although cancers in the advanced T2 categories are often more extensive.