Histological Characteristics of Radical Prostatectomy Specimens in Men with a Serum Prostate Specific Antigen of 4 ng./ml. or Less

[Core needle biopsy twice negative with rising PSA level. Does imaging help?]

In compliance with guidelines in cases of suspected prostate cancer, the standard approach involves transrectal ultrasound-guided systematic biopsies. Currently, according to the new S3 guideline for prostate cancer, 10-12 tissue samples should be collected per patient and session. If these primary specimens are negative, the number of multiple biopsies is generally increased in the second session to improve the diagnostic certainty with more biopsies. At the latest when the second core needle biopsy is performed in the presence of rising prostate-specific antigen (PSA) level, an attempt is made to minimize the risk of overlooking prostate cancer by further increasing the number of multiple biopsies in the sense of achieving saturation. In this instance, the number ranges from 6 to 143 tissue samples per session. Studies have provided evidence that after two systematic random biopsies the same number of additional random biopsies does not accomplish any essential improvement of diagnostic certainty. There are hardly any studies in the literature dealing with the role of imaging procedures after negative prostate biopsies. In a prospective clinical trial including 132 patients with an average of 12 negative previous biopsies, a dramatically high number of prostate carcinomas (66 of 132) could be detected with innovative imaging (1-6 targeted biopsies). This raises the question of how reliably multiple systematic biopsies can in fact exclude the presence of cancer. Thus, particularly after a negative series of multiple biopsies, it appears to be expedient to use specific imaging to enhance diagnostic certainty through quality. However, prospective clinical validation of the diverse innovative methods seems to be important before broad application.

Characteristics and outcome of prostate cancer with PSA <4 ng/ml at diagnosis: a population-based study

This population-based study aims to assess prognosis of prostate cancer diagnosed with prostate-specific antigen (PSA) levels <4 ng/ml in routine care. Materials and methods We compared prostate cancer patients with low PSA values (n=59) with other prostate cancer patients (n=1330) by logistic regression and the Cox model using data from the Geneva Cancer Registry. Results Patients with low PSA values more frequently had early-stage and well differentiated tumours. Nevertheless, 35% presented with aggressive tumour characteristics or metastases. After adjustment for other prognostic factors, prostate cancer-specific mortality was similar for both groups (hazard ratio: 1.1; 95%CI: 0.6-2.2). Conclusion We conclude that cancer with low PSA values at diagnosis is not indolent.

Predictive value of prostate-specific antigen expression in prostate cancer: a tissue microarray study

OBJECTIVES

To evaluate the prognostic potential of prostate-specific antigen (PSA) expression in tumor specimens in a large cohort of prostate cancers treated by prostatectomy. Although serum PSA measurement has been established as a diagnostic and prognostic tool in prostate cancer, no larger studies have been done of the prognostic potential of this parameter.

METHODS

We used a tissue microarray containing samples of 3261 prostatectomy specimens. PSA expression was scored after immunohistochemical staining on a scale from 0 (absent) to 3 (strong) by an investigator unaware of all other variables. The results were correlated with the pre- and postoperative clinical and pathologic parameters and follow-up data.

RESULTS

Of 2556 eligible tumors, PSA expression was strong in 48.0%, moderate in 36.7%, weak in 12.2%, and absent in 3.1%. The loss of PSA expression correlated significantly with a greater Gleason score, the presence of extraprostatic extension, and a peripheral zone prostate cancer location. It was also significantly associated with PSA recurrence after prostatectomy on univariate analysis but not on multivariate analysis containing the pathologic parameters of the prostatectomy specimens. In the subsets of patients with a preoperative PSA value <6 ng/mL or biopsy Gleason score of 3 + 4, the loss of PSA expression in tissue microarray spots was significantly associated with nonorgan-confined disease.

CONCLUSIONS

The results of our study have shown that the loss of PSA expression in tissue samples of prostate cancer is associated with adverse pathologic features and clinical outcome but is not an independent prognostic factor for PSA recurrence after prostatectomy. However, in the biopsy scenario and in subgroups of patients, it might be a useful parameter for predicting extraprostatic tumor extension.

Computerized transrectal ultrasound (C-TRUS) of the prostate: detection of cancer in patients with multiple negative systematic random biopsies

This study was designed to compare the diagnostic yield of computerized transrectal ultrasound (C-TRUS) guided biopsies in the detection of prostate cancer in a group of men with a history of multiple systematic random biopsies with no prior evidence of prostate cancer. The question was asked: Can we detect cancer by C-TRUS that has been overlooked by multiple systematic biopsies? The entrance criteria for this study were prior negative systematic random biopsies regardless of number of biopsy sessions or number of individual biopsy cores. Serial static TRUS images were evaluated by C-TRUS, which assessed signal information independent of visual gray scale. Five C-TRUS algorithms were utilized to evaluate the information of the ultrasound signal. Interpretation of the results were documented and the most suspicious regions marked by C-TRUS were biopsied by guiding the needle to the marked location. Five hundred and forty men were biopsied because of an elevated PSA or abnormal digital rectal exam. 132 had a history of prior negative systematic random biopsies (1-7 sessions, median: 2 and between 6 and 72 individual prostate biopsies, median: 12 cores). Additionally, a diagnostic TUR-P of the prostate with benign result was performed in four patients. The PSA ranged from 3.1-36 ng/ml with a median of 9.01 ng/ml. The prostate volume ranged from 6-203 ml with a median of 42 ml. Of the 132 patients with prior negative systematic random biopsies, cancer was found in 66 (50%) by C-TRUS targeted biopsies. In this group the median number of negative biopsy sessions was two and a median of 12 biopsy cores were performed. From literature we would expect a cancer detection rate in this group with systematic biopsies of approximately 7%. We only found five carcinomas with a Gleason Score (GS) of 5, 25 with GS 6, 22 with GS 7, 8 with GS 8 and even 7 with GS 9. The results of this prospective clinical trail indicates that the additional use of the C-TRUS identifies clinical significant cancerous lesions that could not been visualized or detected by systematic random biopsies in a very high percentage. In addition, the results of the study support the efforts to search for strategies that utilize expertise and refinement of imaging modalities rather than elevating the number of random biopsies (f.e. 141 cores in one session) in the detection of prostate cancer.

Computergest�tzter transrektaler Ultraschall (C-TRUS) in der Diagnostik des Prostatakarzinoms

In the diagnosis of prostate cancer digital rectal examination and transrectal ultrasound (TRUS) are the most utilized methods for clinical evaluation. However, both methods are not able to differentiate between benign and malignant findings with a high amount of certainty. Nevertheless, TRUS is an excellent tool to guide biopsies in practically any region of the prostate. The most significant problem of visual TRUS interpretation is the lack of specificity, especially being an inexperienced user. In order to enhance the diagnostic capabilities of TRUS we developed a computerized analysis of the TRUS signal information (C-TRUS/ANNA), which was validated by the pathohistologic findings of radical prostatectomies. The question was asked: Can C-TRUS detect cancer that has been missed by even multiple systematic biopsies? The entrance criteria was prior negative systematic random biopsies regardless of number of biopsy sessions or number of individual biopsy cores. Five C-TRUS subvisual algorithms were utilized to evaluate the information of the ultrasound signal. The most suspicious regions were marked by C-TRUS and biopsied by guiding a needle into that specific location. In this study 132 with a history of 6-72 negative systematic random biopsies (median: 12 cores) were evaluated by C-TRUS. The PSA ranged from 3.1-36 ng/ml with a median of 9.01 ng/ml. C-TRUS detected in 66 (50%) of these 132 patients cancer by targeted biopsies. In thes 66 men the median number of negative biopsy sessions were two and a median of 12 biopsy cores had been taken. From the literature, we would expect a cancer detection rate in this group with systematic sextant biopsies of about 7%. Only five of the detected carcinomas showed a Gleason Score (GS) of 5, were as 25 had a GS of 6, 22 a GS of 7 and 15 a GS above 7. The results of this prospective clinical trail indicate that C-TRUS is able to identify clinically significant cancers that were missed by even multiple systematic random biopsies. In addition, the concept of searching for strategies that utilize expertise and refinement of imaging modalities is supported rather than just elevating the number of random biopsies (i.e. 141 cores in one session).

Prostate-specific antigen cutoff of 2.6 ng/mL for prostate cancer screening is associated with favorable pathologic tumor features

OBJECTIVES

To evaluate the pathologic characteristics of clinical Stage T1c (nonpalpable, prostate-specific antigen [PSA]-detected) prostate cancers detected in the 2.6 to 4.0-ng/mL PSA range and compare them with Stage T1c cancers concurrently detected in the 4.1 to 10.0-ng/mL PSA range. All cancers were detected in a prostate cancer screening study.

METHODS

We studied 94 patients with clinical Stage T1c prostate cancer diagnosed by four or six-sector ultrasound-guided needle biopsy who underwent radical prostatectomy between June 1995 and December 1996. We included all men whose prostatectomy specimens were processed with complete embedding of all prostatic tissue. Of these, 42 had a PSA level of 2.6 to 4.0 ng/mL and 52 a PSA level 4.1 to 10.0 ng/mL at the time of cancer detection. We determined the tumor volume by complete embedding and grid morphometry, pathologic stage, Gleason sum, and surgical margin status and compared the cancer volume and pathologic tumor stages for each group.

RESULTS

Men with cancer detected at the 2.6 to 4.0 ng/mL PSA range had significantly smaller cancer volumes (1.1 +/- 1.1 cm(3) versus 1.8 +/- 1.5 cm(3), P = 0.02); however, no difference was found in the proportion (11.9% versus 11.5%, P = 0.9, and 23.8% versus 26.9%, P = 0.7, respectively) of tumors that met previously published criteria of "clinically insignificant" (organ confined, less than 0.2 cm(3) tumor volume, Gleason sum 6 or less) or "clinically unimportant" (organ confined, less than 0.5 cm(3) tumor volume, and Gleason sum 6 or less) tumors. Using the lower PSA cutoff point resulted in the detection of a significantly higher percentage of organ-confined tumors (88% versus 63%, P = 0.01).

CONCLUSIONS

The use of a 2.6-ng/mL PSA threshold for screening resulted in the more frequent detection of small, organ-confined tumors without overdetecting possibly clinically insignificant ones.

Tumor characteristics in screening for prostate cancer with and without rectal examination as an initial screening test at low PSA (0.0-3.9 ng/ml)

BACKGROUND

The value of rectal examination as initial screening test for prostate cancer at low PSA values (0.0-3.9 ng/ml) was determined by evaluating the number and tumor characteristics of the cancers detected.

METHODS

Two study populations were subjected to screening with (n = 10,226) and without (n = 10,753) rectal examination as initial screening test. The number of cancers detected at low PSA values for both screening regimens, the corresponding biopsy and radical prostatectomy tumor characteristics were assessed. Possibly harmless cancers were defined as small (< 0.5 ml) organ-confined tumors without Gleason growth-patterns 4/5.

RESULTS

At low PSA, 26.6% (117/440) of screen-detected cancers were detected after the evaluation of a suspicious rectal examination. The number of cancers and tumor aggressiveness features were highly associated with serum-PSA level. The proportion of possibly harmless disease steadily declined from 100% (PSA 0.0-0.9 ng/ml) to 15.4% (PSA 3.0-3.9 ng/ml). Rectal examinations were performed unnecessarily in 94.7-100% of cases, when detection of clinically significant disease was aimed at. Using PSA (and a cut-off of 3.0 ng/ml) as the only screening tool, 24.3% (121/498) of screen-detected cancers were in the PSA range 3.0-3.9 ng/ml, and 60.0% were assessed as clinically significant.

CONCLUSIONS

Rectal examination as initial screening test for prostate cancer at low PSA values may be replaced by screening using serum-PSA only. At PSA levels below 3.0 ng/ml, 289 rectal examinations are required to find one case of clinically significant disease, and 96 rectal examinations are needed to diagnose prostate cancer of any size, grade, or stage.

Defining the window of opportunity in screening for prostate cancer: validation of a predictive tumor classification model

BACKGROUND

Subdividing cancers according to the natural course of disease, both at the time of diagnosis and after radical prostatectomy, may influence management decisions of patients with prostate cancer. We investigated whether categorization of prostate cancers into different prognostic subgroups is feasible.

METHODS

In 218 screened participants of a randomized study, conventional post-operative tumor features were assessed for their accuracy in predicting PSA relapse after radical prostatectomy using Cox regression analysis. Independent prognostic tumor features were combined to identify subsets of cancers with similar biological potential. A cancer was defined that may be curable after its detection by screening tests, though is destined to progress to clinically manifest disease and cancer-related mortality in the absence of screening.

RESULTS

After a median follow-up of 33.0 months, pathological stage (P = 0.03), tumor volume (P = 0.04), and margin status (P = 0.01) each independently predicted PSA relapse after surgery. The proportion of poorly differentiated cancer proved highly superior to the Gleason score and most strongly predicted PSA relapse (P < 0.0001). Based on combined independent prognostic tumor features, a tumor classification model powerfully predicted PSA relapse.

CONCLUSIONS

Based on tumor characteristics, possibly harmless, and conversely, possibly non-curable disease, may be distinguished from cancers that are likely to show clinical progression in the absence of screening and treatment. Prediction of these subclasses prior to treatment may eventually lead to proper patient management.

Lymphatic drainage of prostatic transition and peripheral zones visualized on a three-dimensional workstation

OBJECTIVES

To determine whether the prostate has lymphatic/lymph node drainage that is not sampled by conventional lymphadenectomy and whether the transition and peripheral zones of the prostate have a different lymphatic drainage, because up to one quarter of lymph-node-negative patients who undergo radical prostatectomy will develop distant metastases.

METHODS

Ten patients (mean age 62.3 years, range 50 to 76) scheduled for transrectal ultrasound-guided sextant biopsy because of an elevated serum prostate-specific antigen level of 4 to 10 ng/mL and a normal digital rectal examination were included in this study. All patients underwent ultrasound-guided sextant biopsies. Subsequently, an oily contrast medium was injected into the transition zone (group A, n = 5) or peripheral zone (group B, n = 5) of the prostate under transrectal ultrasound guidance and fluoroscopy. Immediately, 1 hour, and 24 hours after the procedure, anteroposterior and lateral radiographs were obtained. In addition, spiral computed tomography of the abdomen was performed 10 minutes after the procedure and analyzed on a three-dimensional workstation.

RESULTS

No difference in the lymphatic drainage system between the transition and peripheral zones of the prostate was found. In all patients (n = 10), the lymphatic drainage comprised three major routes: (1) the prostate to the lymph nodes along the lateral bony wall of the pelvis to the angle of internal/external iliac lymph nodes to the common iliac lymph nodes, (2) the prostate to the perineal floor to the pudenda internal lymph nodes to the angle of the internal/external iliac lymph nodes to the common iliac lymph nodes, and (3) the prostate to the sacral lymph nodes. In all 10 patients, main contrast medium enhancement was seen immediately after procedure indicating drainage from the prostate to the lymph nodes along the lateral bony wall of the pelvis. Presacral lymph node enhancement was seen in all patients only in the late (24 hours after contrast injection) radiograph.

CONCLUSIONS

Our data suggest that the main lymphatic drainage, irrespective of the prostatic region (transition or peripheral zone), runs to the pelvic regions that are mostly removed by standard lymphadenectomy techniques. However, one has to bear in mind that the prostate has some lymphatic drainage that is not covered by standard lymphadenectomy and therefore carries the risk of metastatic tumor spread.

Prostate-specific antigen-based early detection of prostate cancer--validation of screening without rectal examination

OBJECTIVES

The evaluation of the screening procedures for prostate cancer (PCa) was a part of the protocol of the European Randomized Study of Screening for Prostate Cancer (ERSPC), section Rotterdam, The Netherlands. We sought to establish an improved strategy for the early detection of PCa using a prostate-specific antigen (PSA) cutoff of 3.0 ng/mL or greater as the only indication for prostate biopsy with omission of the digital rectal examination (DRE).

METHODS

In June 1996, 8612 men, 55 to 74 years old, were randomized to screening and were screened within the ERSPC Rotterdam by a PSA level of 4.0 ng/mL or greater or positive DRE or transrectal ultrasound findings as the indication for biopsy. Four hundred thirty men had PCa. Those treated by radical prostatectomy provided the tumor characteristics considered essential for a change in the screening strategies. Various options were evaluated and predictions made by logistic regression analyses. The protocol change was implemented in February 1997. Another 7943 men were screened according to the new protocol (PSA 3.0 ng/mL or greater). The resulting data were used to compare the two protocols.

RESULTS

The detection rate (proportion of PCa in those screened) turned out to be very similar, with rates of 5.0 and 4.7 at a PSA cutoff of 4.0 ng/mL or greater and 3.0 ng/mL or greater, respectively. This was due to a much larger number of cases of PCa per biopsy in the PSA range of 3 to 3.9 ng/mL than expected. The positive predictive value of the PSA range 3.0 to 3.9 ng/mL in the two protocols was 18.0% and 6.4%, respectively. Tumor characteristics were studied on radical prostatectomy specimens from the original protocol. PCa detected with the new screening regimen had a similar distribution of Gleason scores but a larger proportion of confined disease. Tumor volumes were smaller in patients with PSA levels of less than 2.9 ng/mL; the proportion of "minimal disease" in that group was 50% compared with 28% in the group with a PSA level between 3.0 and 3.9 ng/mL.

CONCLUSIONS

Lowering the biopsy indication to a PSA cutoff of 3.0 ng/mL or greater without a DRE improved the positive predictive value from 18.2% to 24.3%. The number of biopsies necessary to detect 1 case of PCa accordingly changed from 5.2 to 3.4. The overall characteristics of the cases detected at that PSA cutoff differed very little from those detected with the regimen based on PSA, DRE, and transrectal ultrasound.

Treatment of refractory interstitial cystitis

Interstitial cystitis is the most therapeutically frustrating condition of the urinary tract. The vast array of treatments available clearly indicates that none is particularly effective. As the majority of patients fail to experience a significant and prolonged response to standard treatments, new options are frequently being developed. These include the oral administration of cimetidine, the intravesical use of hyaluronic acid and BCG, and total cystectomy with the formation of a continent urinary diversion. Unfortunately, the acceptance of many new treatments is based on incomplete evaluation, and this has resulted in a confusing array of disparate alternatives. Effective and durable treatment will not be available until the nature of the disease is better understood and the mechanisms of action of current therapies are elucidated.

Artificial neural network analysis (ANNA) of prostatic transrectal ultrasound

BACKGROUND

Our purpose was to determine the diagnostic potential of a new, computerized method of interpreting transrectal ultrasound (TRUS) information by artificial neural network analysis (ANNA). This method was developed to resolve the current dilemma of visual differentiation between benign and malignant tissue on TRUS. To train and objectively evaluate ANNA, a new precise method of computerized virtual correlation of preoperative ultrasound findings and radical prostatectomy histopathology was devised. After training with this pathologically confirmed digitized TRUS information, ANNA was tested in a blinded study.

METHODS

Following radical prostatectomy, 289 pathology whole-mount sections of 61 patients were correlated digitally with the corresponding TRUS slices. Specific selection of TRUS areas unequivocally identified on the correlated digitized pathohistology resulted in 553 pathology-confirmed representations (samples). Of these, 53 were used for training and 500 were subjected to blind analysis by ANNA.

RESULTS

ANNA classified 378 (99%) of the 381 benign pathology-confirmed samples correctly as benign. The false-positive rate was 1% (n = 3). Of the 119 pathology-confirmed malignant samples, 94 (79%) were classified correctly; 25 (21%) were falsely classified as normal. Out of all 119 cancers, ANNA classified 60 (71%) of the hypoechoic cancers as malignant and 24 (29%) as benign. Surprisingly, 34 (97%) of the isoechoic cancers were correctly classified by ANNA, missing only one sample.

CONCLUSIONS

The introduction of ANNA enhanced the accuracy of TRUS prostate cancer identification. Although not all malignant areas were detected, cancer was detected in each patient. The ability to detect isoechoic cancerous lesions appears to be the essential innovation over conventional TRUS interpretation.

Observations on pathology trends in 62,537 prostate biopsies obtained from urology private practices in the United States

OBJECTIVES

To evaluate pathology trends of 62,537 first-time prostate needle-core biopsies submitted by office-based urologists, processed at a single pathology laboratory.

METHODS

Prostate biopsy cases obtained over a 2-year period were assessed. Patient information included age, digital rectal examination (DRE) status, and prostate-specific antigen (PSA) serum levels. Biopsy pathology results included the number of tissue samples per case, Gleason score, presence of Gleason grades 4 or 5, percent of biopsy length with evidence of cancer, number of samples with cancer per biopsy, and determination of DNA ploidy status using microspectrophotometry.

RESULTS

Adenocarcinoma, suspicious lesions, and isolated high-grade prostatic intraepithelial neoplasia (PIN) were diagnosed in 38.3%, 2.9%, and 4.1% of the biopsies, respectively. For each serum PSA and age range assessed, the positive biopsy rate and incidence of critical pathologic features increased consistently. The average percentage of biopsy length with evidence of tumor, the percentage of cases with Gleason grades 4 or 5, and the percentage of cases with an abnormal DNA ploidy all decreased significantly over the 2-year period (P <0.01).

CONCLUSIONS

The number of tissue cores and anatomic sites (locations) being sampled per biopsy are increasing. The tumor size detected and percentage of cases with Gleason grades 4 and 5 are decreasing. There has been a slight increase in the number of biopsies performed on men younger than 60 years of age and a slight decrease in biopsies performed on men older than 70 years of age. The decline in meaningful pathologic features observed in biopsies over time may be clinically relevant to improved disease management.

The results of prostate carcinoma screening in the U.S. as reflected in the surveillance, epidemiology, and end results program

BACKGROUND

The rapid escalation in the incidence of prostate carcinoma between the years 1988 and 1992 has been attributed to prostate specific antigen screening. There have been concerns regarding the possible diagnosis and treatment of insignificant tumors in the absence of randomized, controlled trial evidence of a decrease in mortality. Descriptive studies suggest that serial screening decreases the detection of advanced disease. In November 1996, the National Center for Health Statistics recorded a decrease in prostate carcinoma mortality.

METHODS

The basis of this analysis is 208,234 prostate carcinoma cases diagnosed between 1973 and 1993 in population-based Surveillance, Epidemiology, and End Results registries. The general staging system was used rather than that of the American Joint Committee on Cancer to permit observation of long term trends. Grade incorporating Gleason scores was used as an indication of the significance of the prostate carcinoma. Age-adjusted survival rates were used to separate prostate carcinoma deaths from deaths due to other causes.

RESULTS

The increase in the incidence of prostate carcinoma has been greater than for any other malignancy. The increase was largely in Grade 2 significant tumors and not in Grade 1 (15%) insignificant tumors. There was a decrease in the detection of advanced disease. After the peak incidence in 1992, a progressive decrease to near baseline levels occurred. Approximately 38% of all deaths were from prostate carcinoma. Deaths from other causes increased with age. When corrected for death from other causes, men age > 69 years had a greater rate of death from prostate carcinoma than men age 50-69 years. Approximately 61% of all deaths from prostate carcinoma occurred within 5 years of diagnosis and 88% within 10 years. The 10-year survival rate for patients treated by radical prostatectomy was 100%, 78% for patients treated by radiation, and 33% for patients treated with other (noncomparable modalities).

CONCLUSIONS

The indirect evidence suggested that prostate carcinoma screening of men ages >50 years decreased the incidence of distant disease, which influences the mortality rate.

Update on the appropriate staging evaluation for newly diagnosed prostate cancer

PURPOSE

Prostate cancer clinical staging methods and decision support tools were reviewed to assess their accuracy to predict pathological staging results and determine what comprises an appropriate clinical staging evaluation.

MATERIALS AND METHODS

The MEDLINE data base was searched and 238 abstracts were obtained. Data were extracted from 142 articles that evaluated the preoperative accuracy of digital rectal examination, prostate specific antigen, prostatic acid phosphatase, systematic biopsy parameters (including Gleason scoring), seminal vesicle biopsy, various imaging studies and pelvic lymphadenectomy versus pathological staging results. The sensitivity, specificity and accuracy rates were calculated and tabulated from the reported data on each method or decision support tools for organ confined, nonorgan confined and lymph node metastatic tumor.

RESULTS

Decision support tools based on logistic regression analysis, which combine several statistically independent staging parameters, had greater accuracy than any single clinical staging method alone. The most accurate decision support tools for clinical staging combined digital rectal examination (T stage), systematic biopsy parameters (including Gleason scoring) and prostate specific antigen.

CONCLUSIONS

The components that comprise the most accurate decision support tools for clinical staging represent an appropriate staging evaluation for the newly diagnosed prostate cancer patient in 1997. Limited use of radiographic imaging and seminal vesicle biopsy may be indicated in select patients to detect bone metastases, and plan pelvic lymphadenectomy and surgical therapy.

Statistical review and analysis of the relationship between serum prostate specific antigen and age

PURPOSE

We investigated the possibility that the variations in the reported correlation coefficient (r) between age and serum prostate specific antigen (PSA) is simply a reflection of the differences in the age mix of the population studied, that is the younger the population the greater the correlation and vice versa. Also, we quantified the value of r for different age groups to evaluate finally the plausibility of its practical application on sound statistical basis.

MATERIALS AND METHODS

Bivariate and multivariate regression analyses were done of all identified reports in the literature that specified the exact value of r and the percentage distribution of the population studied in 10-year age groups.

RESULTS

The correlation coefficient between r and the percentage of the population in different age groups was statistically significant, confirming the hypothesis that the greater the percentage of younger population in the study, the greater the value of r and vice versa. The correlation between age and PSA did change with age. It was significantly high in the fifth to sixth decades of life (range 0.5 to 0.7) [corrected] and markedly decreased in decade 7 to become low and insignificant in decade 8.

CONCLUSIONS

The value of the correlation between age and PSA is sufficiently high to allow for its practical application up to age 60 years. Beyond that age the correlation is so low that its practical application becomes statistically flawed. This finding seems to match the practical experience when applying age-specific PSA ranges in the diagnosis of early prostate cancer.