Utility of preoperative serum prostate-specific antigen concentration and biopsy Gleason score in predicting risk of pelvic lymph node metastases in prostate cancer

Staging laparoscopic pelvic lymphadenectomy in prostate cancer

OBJECTIVE

To assess the results of transperitoneal laparoscopic pelvic lymphadenectomy as a separate staging procedure in patients with early prostate cancer.

PATIENTS AND METHODS

The results were reviewed from the first 27 patients with prostate cancer admitted for laparoscopic lymphadenectomy between January 1994 and March 1998. Initially, all patients with a negative bone scan and either a negative computed tomography or negative magnetic resonance scan were admitted for laparoscopic staging. After several reports detailing ways of reducing the number of negative lymphadenectomy operations, from July 1996 only those patients with a preoperative prostate specific antigen (PSA) serum level of >10 ng/mL were admitted to the study. All procedures were performed by one experienced laparoscopic surgeon. A radical retropubic prostatectomy was performed as a separate procedure by a consultant urologist within 2 weeks. The effectiveness of the staging operation was analysed by assessing the nodal yield, and the results, including operative duration, complications and length of stay, were compared with other published series. Further analysis was provided by reviewing the PSA levels, Gleason grade sum and clinical digital staging.

RESULTS

The nodal yield was similar to that published in series from other institutions, with a median (range) of 6.5 (0-12). However, the operation was significantly quicker, at a median (range) of 55 (40-110) min for a bilateral dissection. There were only minor complications, with no detectable reduction in complications with experience; the median (range) postoperative stay was 1 (1-4) days. Two of the 27 patients had metastatic disease within the lymph nodes. If a PSA level of >10 ng/mL had been instituted as an entry criteria at the start of the study, six patients would have been excluded and thus the positive lymphadenectomy rate would have been two of 21 patients (10%). Of 54 patients eligible to enter the study, half did not require a lymphadenectomy.

CONCLUSIONS

Laparoscopic transperitoneal lymphadenectomy can be performed expeditiously and safely. A two-stage procedure in some patients with prostate cancer is the management of choice. Attention to carefully closing the peritoneum with sutures minimizes any retropubic adhesions and no problems associated with the staging procedure were encountered during subsequent radical retropubic prostatectomy. In efforts to reduce negative staging lymphadenectomies, the exclusion values for staging should not be set too high (PSA and Gleason grading sum). Such practice, despite a relatively safe staging procedure, would lead to unnecessary radical prostatectomy.

Prostate-specific antigen ratio correlates with aggressiveness of histology grades of prostate cancer

OBJECTIVES

To compare prostate-specific antigen (PSA) ratio to total PSA (tPSA) assay for prostate cancer diagnosis and to study the correlation of PSA ratio with histology grade of prostate cancer.

METHODS

Among 334 selected cases, 136 had benign prostate diseases and 198 had prostate cancer. All cases underwent transrectal ultrasound (TRUS) and tissue biopsies within 6 months of their tPSA measurements. All of the tPSA levels taken were between 2 and 20 microg/L. The serum tPSA and free PSA were assayed using the Abbott AxSYM immunoassay system (Abbott Laboratories; Abbott Park, IL, USA). The PSA ratios of patients with prostate cancer were compared to those with benign prostate diseases (BPD) using the Student's t test. Correlation between the histology grades and PSA ratios was calculated by Pearson test. Receiver operating characteristic (ROC) curves were generated from sensitivities and specificity of various PSA ratios and tPSA levels.

RESULTS

We found an inverse correlation between PSA ratios and aggressiveness of histology grades (r = -0.995, p < 0.01). The higher the histology grade, the lower the PSA ratio tended to be, and the more sensitive and specific the PSA ratio was in the diagnosis of prostate cancer. No correlation was found between histology grades and tPSA levels. A PSA ratio of 0.25 diagnosed 93% of patients with Gleason score greater than 7 and 83% of all prostate cancer patients. It would have reduced unnecessary biopsies by 23% compared to the tPSA level of 4 microg/L. Sensitivity of PSA ratios was higher and specificity was lower in high tPSA level group than they were in low tPSA level group.

CONCLUSIONS

PSA ratio inversely correlates to aggressiveness of prostate cancer and has a potential to predict histology grade of prostate cancer. PSA ratio improves sensitivity and specificity for prostate cancer diagnosis compared to tPSA assay.

Novel staging tool for localized prostate cancer: a pilot study using genetic adaptive neural networks

PURPOSE

An estimated $1.5 billion is spent annually for direct medical expenses and an additional $2.5 billion for indirect costs for the management of prostate cancer. Today there are several procedures for staging prostate cancer, including lymph node dissection. Despite these procedures, the accuracy of predicting extracapsular disease remains low (range 37 to 63, mean 45%). Use of multiple staging procedures adds significantly to the costs of managing prostate cancer. Recently artificial intelligence based neural networks have become available for medical applications. Unlike traditional statistical methods, these networks do not assume linearity or homogeneity of variance and, thus, they are more accurate for clinical data. We applied this concept to staging localized prostate cancer and devised an algorithm that can be used for prostate cancer staging.

MATERIALS AND METHODS

Our study comprised 1,200 men with clinically organ confined prostate cancer who underwent preoperative staging using serum prostate specific antigen, systematic biopsy and Gleason scoring before radical prostatectomy and lymphadenectomy. The performance of the neural network was validated for a subset of patients and network predictions were compared with actual pathological stage. Mean patient age was 62.9 years, mean serum prostate specific antigen 8.1 ng./ml. and mean biopsy Gleason 6. Of the patients 55% had organ confined disease, 27% positive margins, 8% seminal vesicle involvement and 7% lymph node disease. Of margin positive patients 30% also had seminal vesicle involvement, while of seminal vesicle positive patients 50% also had positive margins.

RESULTS

The sensitivity of the network was 81 to 100%, and specificity was 72 to 75% for various predictions of margin, seminal vesicle and lymph node involvement. The negative predictive values tended to be relatively high for all 3 features (range 92 to 100%). The neural network missed only 8% of patients with margin positive disease, and 2% with lymph node and 0% with seminal vesicle involvement.

CONCLUSIONS

Our study suggests that neural networks may be useful as an initial staging tool for detection of extracapsular extension in patients with clinically organ confined prostate cancer. These networks preclude unnecessary staging tests for 63% of patients with clinically organ confined prostate cancer.

Systematic sextant biopsies improve preoperative prediction of pelvic lymph node metastases in patients with clinically localized prostatic carcinoma

PURPOSE

An algorithm including the results of systematic sextant biopsies was statistically developed and evaluated to predict the probability of pelvic lymph node metastases in patients with clinically localized carcinoma of the prostate.

MATERIALS AND METHODS

Clinical stage, serum prostate specific antigen concentration, Gleason score, number of positive biopsies, number of biopsies containing any Gleason grade 4 or 5 cancer and number of biopsies predominated by Gleason grade 4 or 5 cancer were recorded in 345 patients undergoing pelvic lymph node dissection and correlated with the incidence of lymph node metastases. Multivariate logistic regression, and classification and regression trees analyses were performed.

RESULTS

In univariate analysis all variables had a statistically significant influence on lymph node status. Logistic regression showed that the amount and distribution of undifferentiated Gleason grade 4 and 5 cancer in the biopsies were the best predictors of lymphatic spread followed by serum prostate specific antigen. Classification and regression trees analysis classified 79.9% of patients who had 3 or fewer biopsies with Gleason grade 4 or 5 cancer and no biopsies predominated by undifferentiated cancer as a low risk group. In this group positive lymph nodes occurred in only 2.2% (95% confidence interval 0.8 to 4.7%).

CONCLUSIONS

Including the results of systematic sextant biopsies substantially enhances the predictive accuracy of algorithms that define the probability of lymph node metastases in prostatic cancer. Patients thus defined as having no lymphatic spread could potentially be spared pelvic lymph node dissection before definitive local treatment.

Localised carcinoma of the prostate: a paradigm of uncertainty

The incidence and prevalence of prostate cancer is increasing. A number of aetiological factors including age, race, family history and diet have been implicated. The majority of patients present with disease which is amenable only to palliation. Digital rectal examination, serum prostate-specific antigen and transrectal ultrasound can lead to a prostatic biopsy. Transrectal ultrasound, magnetic resonance imaging, bone scan and a chest X-ray are used for staging. The management of localised cancer is shrouded in uncertainty. Three options exist, watchful waiting, radiotherapy, and radical total prostatectomy. The published data are inadequate for a valid comparison of these, and none has been shown to offer an advantage. Surgery, and to a lesser degree radiotherapy, have a significant morbidity. It is hoped that through better understanding our management of this disease will improve.

Interobserver variation in prostate cancer Gleason scoring: are there implications for the design of clinical trials and treatment strategies?

A series of prostate cancer histological slides from 71 patients were used to measure the interobserver variation among three pathologists awarding a Gleason score. The study was prompted on account of the use of histological grade to stratify patients prior to randomization within two clinical trials currently recruiting at our centre, and a proposed study that would allocate treatment depending upon the score awarded. The pathologists were expected to award a score based upon their day to day experience, there being no consensus meeting before-hand to agree on the grey areas of the Gleason grading system. We used the kappa statistic to assess the level of agreement. This was calculated both for comparison of the raw scores awarded by the three observers, as well as the grouped scores corresponding to those groupings used for the purposes of stratification in the two trials. The extent of the interobserver variation (weighted kappa) for the raw scores (Gleason scores 2-10) was 0.16 to 0.29 and for the grouped scores (Gleason scores < or = 7 or > or = 8), kappa was 0.15 to 0.29. For the raw scores, the total agreement rate was 9.9% and the total disagreement 26.8%; for the grouped scores the total agreement rate was 43.7%. It is concluded that, despite this level of agreement there is no concern regarding stratification using the Gleason score, because of the subsequent randomization. However, using a reported Gleason score to determine treatment might be inappropriate. These data indicate the value of a central review process for pathology grading in clinical trials, especially where the treatment is directly affected by this information.

The Rational Choice in the Diagnosis and Therapy of Prostatic Cancer

The authors analyse which is the best approach in diagnosing and staging prostatic cancer. They tackle the problem of screening by analysing current methods, concluding that PSA measurement is the best. It is impossible not to consider a combination of prognostic factors (Gleason score, PSA, clinical staging) when choosing pre-operative staging methods.

The anatomic radical perineal prostatectomy: a contemporary and anatomic approach

OBJECTIVES

We applied the advances in anatomic techniques as developed for the radical retropubic prostatectomy to the perineal approach to radical prostatectomy. The anatomic radical perineal prostatectomy maximizes cancer control and minimizes postoperative incontinence and impotence. This technique capitalizes on the many advantages associated with the perineal approach to the prostate.

METHODS

The anatomic radical perineal prostatectomy addresses the posterior surface and posterior bladder neck regions prior to urethral division at the prostatic apex. Anatomic dissection of the striated urethral sphincter and preservation of the bladder neck, as well as a "watertight" anastomosis, are accomplished with excellent exposure. Cavernosal nerve preservation is possible in appropriately selected patients. Data are accumulated prospectively and reported herein.

RESULTS

Prostate-specific antigen detectability is seen in 2% and 4% of pT2 and pT2 to T3b cases, respectively at an average follow-up of 1 year. Immediate full continence is seen in 30% of cases; ultimately, 97.5% achieve full urinary control. Nerve-sparing techniques result in spontaneous erectile activity in 73%. Average length of hospital stay is less than 2 days, with most recent patients discharged on the day after surgery.

CONCLUSIONS

The anatomic radical perineal prostatectomy is a safe and effective method of treating men with clinically localized prostate cancer and should be part of every urologist's surgical armamentarium.

Should cryosurgery be considered a therapeutic option in localized prostate cancer?

Cryosurgical ablation of the prostate currently is under investigation as a potential treatment for localized prostate cancer. Results to date indicate that the majority of patients have negative biopsies and a marked reduction in prostate-specific antigen levels following cryotherapy. This treatment, however, is associated with significant side effects, notably bladder outflow obstruction, impotence, and incontinence, and its long-term durability is still unknown.

A new minimally invasive open pelvic lymphadenectomy surgical technique for the staging of prostate cancer

We report a new method for lymphadenectomy, the minilaparotomy (inguinal) pelvic lymph node dissection (MLPLND), and compare it with laparoscopic pelvic lymph node dissection (LPLND) in terms of cost, effectiveness, operation time and morbidity. We reviewed a series of 111 consecutive patients: 51 had MLPLND and 60 had LPLND. All patients had proved adenocarcinoma of the prostate by biopsy. Of the MLPLND patients, only 1 had to stay overnight in the hospital, and all left within 24 hours. Pelvic lymphadenectomy consisted of nodal removal along the internal iliac vessels and the external iliac vein, and nodes of the obturator foramen. A total of 14% of the patients had disease involving the lymph nodes. The cost of MLPLND was 50% of the cost of LPLND, with no interoperative or postoperative morbidity. This new operation can be performed thoroughly an inexpensively in approximately 35 minutes, with little or no morbidity. Since the drawbacks of laparoscopic techniques associated with instrument costs and the learning curve for this technically difficult operation are eliminated, staging pelvic lymphadenectomy can be performed routinely on a wider variety of patients with potential metastatic disease. Currently, we recommend MLPLND to any patient with a tumor of Gleason score 7 or higher or a serum prostate-specific antigen value of 15 ng/mL or higher.

Predicting the patient at low risk for lymph node metastasis with localized prostate cancer: an analysis of four statistical models

PURPOSE

Statistical models using preoperative Prostate-Specific Antigen, Gleason primary grade or score of the biopsy specimen, and clinical stage have been developed to predict those patients with clinically localized prostate cancer at low risk for lymph node metastasis. It has been recommended that these patients do not require pelvic lymph node dissections. Four such models were evaluated to assess their accuracy in identifying this subgroup of patients.

METHODS AND MATERIALS

We reviewed the records of 214 patients with clinically localized prostate cancer who underwent pelvic lymph node dissections. Data from these patients were entered into the four models.

RESULTS

Lymph node metastasis was detected in 14% of patients. The results showed the following for each of the proposed models respectively: 78, 50, 76, and 42% of the patients were identified as low risk and, hence, would be spared pelvic lymph node dissections. The false negative rates are 13 (7.8%), 5 (4.6%), 14 (8.6%), and 1 (1.1%). Sensitivities are 56.7, 83.3, 53.3, and 96.7%.

CONCLUSIONS

While the pelvic lymph node dissection is the most accurate method of detecting occult nodal metastasis, statistical models can identify a cohort of low risk patients that may be spared lymphadenectomy.

Lack of correlation between prostate-specific antigen and the presence of measurable soft tissue metastases in hormone-refractory prostate cancer

Appropriate staging procedures for patients with hormone-refractory prostate cancer are poorly defined. In particular, there are no studies correlating prostate-specific antigen (PSA) with more traditional methods of staging. We have evaluated the abdominal/pelvic CT scan, bone scan, and PSA results following initial diagnosis of hormone-refractory prostate cancer in 177 consecutive patients (median age = 63.1 years, range 45-80). Thirty-four patients (19.2%) had measurable lesions (> or = 2 cm) on CT scan compatible with metastatic disease. Of the patients with measurable lesions, 29/34 (85.3%) had retroperitoneal and/or pelvic adenopathy; 5 patients (14.7%) had measurable lesions in the liver. Other sites of metastatic disease were detected in less than 1% of the patients receiving scans. All patients had bone scan abnormalities compatible with metastatic disease. Results of these imaging studies were then compared to PSA serum concentration (Abbott IMx). The mean PSA concentration was not different in those patients with soft tissue disease as compared to those without soft tissue involvement and there was no correlation between PSA concentration and the presence or absence of measurable soft tissue disease. In contrast to previously published studies in hormone-naïve prostate cancer patients, these studies in hormone-refractory patients indicate that the detection of metastatic disease by standard radiological procedures cannot be predicted by measurement of serum PSA.

Using prostate-specific antigen to eliminate unnecessary diagnostic tests: significant worldwide economic implications

As the 21st century approaches, it is necessary for urologists worldwide to diagnose and stage malignancies in a cost-effective manner. With the recent advances in the use of prostate-specific antigen (PSA), it is now possible to avoid many time-consuming, expensive, and invasive procedures that have been commonplace in the past. PSA has replaced transrectal ultrasonography (TRUS) as a first-line diagnostic test for evaluating men for early, curable prostate cancer. In older men, the use of age-specific reference ranges for serum PSA can significantly decrease the number of prostate biopsies that are routinely performed. With regard to staging procedures, PSA can now be used successfully to eliminate the bilateral pelvic lymphadenectomy in 30% of men with clinically localized disease and the radionuclide bone scan in 40% of patients with newly diagnosed prostate cancer. In the discussion that follows, the use of serum PSA in the diagnosis and staging of prostate cancer will be discussed. In addition, the economic benefit achieved through proper use of this tumor marker will be reviewed.

Open pelvic lymph node dissection for prostate cancer: a reassessment

OBJECTIVES

To provide a risk-to-benefit analysis of open staging pelvic lymph node dissection (PLND) for prostate cancer.

METHODS

The medical records of all patients presenting with prostate cancer from July 1989 to April 1994 were reviewed. A total of 245 patients with clinically localized disease were selected to undergo radical retropubic prostatectomy (RRP) preceded by open PLND. Univariate and multivariate analyses were performed to evaluate the predictive value of the preoperative serum prostate-specific antigen (PSA) concentration, clinical stage, and Gleason score with regard to final nodal status. The cost and morbidity associated with PLND in the setting of RRP was also defined.

RESULTS

Overall, only 16 patients (6.5%) had lymph node metastases. Lymph node involvement correlated significantly with elevated serum PSA values (P = 0.0001), high Gleason score (P = 0.0022), and advanced clinical stage (P = 0.0001). Lymph node metastases were particularly uncommon in patients with nonpalpable tumors (1 of 67 [1.5%]), PSA values less than 10 (2 of 154 [1.3%]), and Gleason score less than 6 (1 of 26 [3.8%]). Overall, 179 patients (73.1%) presented with at least one or more of these favorable characteristics, and only 4 (2.2%) had lymph node involvement. Complications related to the lymphadenectomy occurred in 10 patients (4.1%). The cost per metastasis diagnosed in patients with low-risk characteristics was approximatley $43,600.

CONCLUSIONS

An open staging PLND may no longer be justified on a routine basis in patients undergoing radical retropubic prostatectomy.

A guide to the interpretation of serum prostate specific antigen levels

OBJECTIVE

To review the factors that affect the concentration of prostate specific antigen (PSA) in the serum.

RESULTS

The discussion includes the structure of PSA; its distribution and metabolism; various analytical aspects of PSA measurements; the effects of clinical manipulations on PSA, including digital rectal examination, transrectal ultrasound, cystoscopy, biopsy and transurethral resection of the prostate; factors affecting PSA levels in health, in benign disease, and in prostate cancer; the effect of various treatments on PSA; and the issue of reference ranges.

CONCLUSION

Laboratory staff and physicians must take many factors into consideration when interpreting PSA results.