TRENDS IN GLEASON SCORE FOR PROSTATE CANCER DIAGNOSED BETWEEN 1983 AND 1993

Diagnostic assessment program for prostate cancer: Lessons learned after 2 years and degree of compliance to Canadian guidelines

BACKGROUND

In 2018, our Institute launched the Diagnostic Assessment Program (DAP) for prostate cancer. It enabled quick access to a urologist for patients presented to family physician with elevated PSA and allowed fast multidisciplinary patient care. We aim to document our data over 2 years in comparison to data before implementation of DAP and its impact on the degree of adherence to Canadian guidelines.

METHODS

From April 2016 to April 2020, 880 patients who were evaluated for prostate cancer at Thunder Bay Regional Health Sciences Centre (TBRHSC) were included in this study. Patients' characteristics, clinical data, waiting times and line of treatment before and after implementation of DAP were calculated and statistically analysed.

RESULTS

The median waiting time to urology consultation was significantly reduced from 68 (IQR 27-168) days to 34 (23-44) days (p < 0.001). The time from patient's referral to prostate biopsy decreased substantially from 34 (20-66) days to 18(11- 25) days after DAP (p < 0.001). After DAP, the percentage of Gleason 6 detected prostate cancers were significantly increased (19.7% to 30%) (p = 0.02). After DAP, rate for intermediate-risk patients elected for external beam radiotherapy (from 53.5% to 57.9%, p = 0.53) and radical prostatectomy (from 34.5% to 39.4%, p = 0.47) increased. More compliance to Canadian guidelines was observed in intermediate risk patients (88% vs 97.3%, p =.008).

CONCLUSIONS

Implementation of DAP has led to a notable reduction of waiting time to urology consult and prostate biopsy. There is significant increase in Gleason 6 detected prostate cancer. Increased compliance to Canadian guidelines was detected in intermediate risk patients.

Evolution, controversies and the future of prostate cancer grading

Histological grading of prostate cancer is one of the most important tissue-based parameters for prediction of outcome and treatment response. Gleason grading remains the foundation of prostate cancer grading, but has undergone a series of changes in the past 30 years, often initiated by consensus conference decisions. This review summarizes the most important modifications that were introduced by the 2005 and 2014 International Society of Urological Pathology (ISUP) revisions of Gleason grading and discusses the impact that these have had on current grading practices. A considerable inflation in Gleason scores has been observed, especially following the ISUP 2005 revision, and the effects of this are discussed. ISUP 2014 grading recommendations are described, including the reporting of ISUP grades 1-5. Controversial issues include methods for reporting of grades on needle biopsies, reporting of percent Gleason grades 4/5 and grading of cribriform and intraductal carcinoma of the prostate. Educational programs developed recently to promote standardization of grading are described and their results assessed.

Two susceptibility loci identified for prostate cancer aggressiveness

Most men diagnosed with prostate cancer will experience indolent disease; hence, discovering genetic variants that distinguish aggressive from nonaggressive prostate cancer is of critical clinical importance for disease prevention and treatment. In a multistage, case-only genome-wide association study of 12,518 prostate cancer cases, we identify two loci associated with Gleason score, a pathological measure of disease aggressiveness: rs35148638 at 5q14.3 (RASA1, P=6.49 × 10(-9)) and rs78943174 at 3q26.31 (NAALADL2, P=4.18 × 10(-8)). In a stratified case-control analysis, the SNP at 5q14.3 appears specific for aggressive prostate cancer (P=8.85 × 10(-5)) with no association for nonaggressive prostate cancer compared with controls (P=0.57). The proximity of these loci to genes involved in vascular disease suggests potential biological mechanisms worthy of further investigation.

Gleason inflation 1998-2011: a registry study of 97,168 men

OBJECTIVES

To study long-term trends in Gleason grading in a nationwide population and to assess the impact of the International Society of Urological Pathology (ISUP) revision in 2005 of the Gleason system on grading practices, as in recent years there has been a shift upwards in Gleason grading of prostate cancer.

PATIENTS AND METHODS

All newly diagnosed prostate cancers in Sweden are reported to the National Prostate Cancer Register (NPCR). In 97 168 men with a primary diagnosis of prostate cancer on needle biopsy from 1998 to 2011, Gleason score, clinical T stage (cT) and serum levels of prostate-specific antigen (s-PSA) at diagnosis were analysed.

RESULTS

Gleason score, cT stage and s-PSA were reported to the NPCR in 97%, 99% and 99% of cases. Before and after 2005, Gleason score 7-10 was diagnosed in 52% and 57%, respectively (P < 0.001). After standardisation for cT stage and s-PSA with 1998 as baseline these tumours increased from 59% to 72%. Among low-risk tumours (stage cT1 and s-PSA 4-10 ng/mL) Gleason score 7-10 increased from 16% in 1998 to 40% in 2011 (P trend < 0.001), mean 19% and 33% before and after 2005 (P < 0.001). Among high-risk tumours (stage T3 and s-PSA 20-50 ng/mL) Gleason score 7-10 increased from 65% in 1998 to 94% in 2011 (P trend < 0.001), mean 78% and 90% before and after 2005 (P < 0.001). A Gleason score of 2-5 was reported in 27% in 1998 and 1% in 2011. Gleason score 5 decreased sharply after 2005 and Gleason score 2-4 was almost abandoned.

CONCLUSIONS

There has been a gradual shift towards higher Gleason grading, which started before 2005 but became more evident after the ISUP 2005 revision. Among low-stage tumours reporting of Gleason score 7-10 was more than doubled during the study period. When corrected for stage migration upgrading is considerable over recent decades. This has clinical consequences for therapy decisions such as eligibility for active surveillance. Grading systems need to be as stable as possible to enable comparisons over time and to facilitate the interpretation of the prognostic impact of grade.

Changing trends in symptomatology, diagnostics, stage and survival of prostate cancer in Northern Finland during a period of 20 years

BACKGROUND

Prostate cancer is the most common cancer among men in many countries. The aim of the present study was to find out how the symptoms leading to a diagnosis, diagnostic procedures and stages of the disease among prostate cancer patients have changed over a period of 20 years.

METHODS

This retrospective chart review consisted of 421 prostate cancer patients whose treatment was started in the years 1982, 1987, 1992, 1997 and 2002 at the Oulu University Hospital. Earlier prostatic disorders, specific urological symptoms, diagnostic procedures, the TNM classification and histological grade were recorded.

RESULTS

The number of symptom-free prostate cancer patients increased over the 20 years, as did the number of men suffering from chronic prostatitis, although the latter increase was not statistically significant. A drop in the number of clinical T4 cases and increase of clinical T1 and clinical T2 cases was recorded but no clear change in the histological distribution occurred. The 5-year prostate cancer-specific survival improved significantly over the 20 years. The urologist was found to be the person who was contacted first most often.

CONCLUSIONS

Our data indicate that the number of prostate cancer patients has increased hugely over the period from 1982 to 2002 and although the clinical T stage has moved towards earlier stages, the proportion of well differentiated cancers remains low, so that most patients have clinically significant cancer with the need of some form of therapy. Further, prostate cancer-specific survival improved significantly over the period.

Socioeconomic variation and prostate specific antigen testing in the community: a United Kingdom based population study

PURPOSE

We examined the association of prostate specific antigen testing with prostate cancer incidence, tumor differentiation and mortality according to socioeconomic status.

MATERIALS AND METHODS

Participants were 96,484 men between 40 and 99 years old without preexisting prostate cancer who were registered with a general practitioner in the Tayside region of Scotland, United Kingdom, between January 1, 2003 and December 31, 2008. We performed a retrospective cohort analysis using anonymized health data, including biochemistry data on prostate specific antigen tests, Scottish Index of Multiple Deprivation, cancer registry data set and General Register Office for Scotland death records. Main outcome measures were prostate specific antigen testing, prostate cancer incidence and death.

RESULTS

Men in the most affluent Scottish Index of Multiple Deprivation quintile had a greater chance of undergoing a prostate specific antigen test (OR 1.48, 95% CI 1.40-1.57, p <0.001) and having prostate cancer (OR 1.48, 95% CI 1.15-1.91, p = 0.002) than men in the most deprived quintile, adjusting for age. There was no association between deprivation index quintile and prostate cancer death.

CONCLUSIONS

Increased affluence was associated with a higher likelihood of a prostate specific antigen test and a higher incidence of prostate cancer. However, there were no observed differences by social class of the likelihood of a positive prostate specific antigen test or prostate cancer related death.

Temporal changes in the pathologic assessment of prostate cancer

Thirty years have witnessed dramatic changes in the manner in which we diagnose and manage prostate cancer. With prostate-specific antigen screening, there was a shift towards smaller, clinically localized tumors. Tumors are often multifocal and display phenotypic and molecular heterogeneity. Pathologic evaluation of tissue obtained by needle biopsy remains the gold standard for the diagnosis and risk assessment of prostate cancer. Years of experience with grading, along with changes in the amount of biopsy tissue obtained and diagnostic tools available, have produced shifts in grading practices among genitourinary pathologists. Trends in Gleason grading and advances in pathological risk assessment are reviewed with particular emphasis on recent Gleason grading modifications of the International Society of Urologic Pathology. Efforts to maximize the amount of information from pathological specimens, whether it be morphometric, histochemical, or molecular, may improve predictive accuracy of prostate biopsies. New diagnostic techniques are needed to optimize management decisions.

Current perspectives on Gleason grading of prostate cancer

The 5-tier Gleason grading system for prostate cancer, introduced in 1966, has been proven to be one of the main independent predictors of prostate cancer outcome. This review addresses interobserver concordance in Gleason grading; the persistence of grading discrepancies with frequent upgrading from the biopsy to the prostatectomy specimen; the 2005 International Society of Urologic Pathologists' modifications to Gleason grading; the impact of this modified grading on grade migration and outcome prediction; and molecular correlates of cancer morphology. Data from the most recent years are emphasized.

The impact of the 2005 International Society of Urological Pathology (ISUP) consensus on Gleason grading in contemporary practice

AIMS

To investigate the impact of the 2005 International Society of Urological Pathology (ISUP) Gleason grading consensus in contemporary practice.

METHODS AND RESULTS

The Gleason scores (GS) were compared in two consecutive patient cohorts with matched biopsies and prostatectomies: (i) 908 patients evaluated before the ISUP consensus (July 2000-June 2004) and (ii) 423 patients evaluated after the ISUP consensus (October 2005-June 2007). All biopsies and prostatectomies were performed and scored in one institution and were sampled and processed identically. There was a higher percentage of biopsy and prostatectomy specimens with GS > or = 7 after the ISUP consensus (GS > or = 7 on biopsy in 32% before ISUP versus 46% after ISUP; GS > or = 7 on prostatectomy in 53% before ISUP versus 68% after ISUP; P < 0.001). No significant difference in the complete and + or -1 unit Gleason agreement was found before and after the ISUP consensus. There was a trend towards better complete agreement for GS > or = 7 after the ISUP consensus.

CONCLUSIONS

There was a shift towards higher GS on biopsy and prostatectomy in our practice after the ISUP consensus, although - there was no significant impact on the biopsy-prostatectomy Gleason agreement. The significance of this shift for patient management and prognosis is uncertain.

Clinical presentation and initial management of black men and white men with prostate cancer in the United Kingdom: the PROCESS cohort study

Background:

In the United States, Black men have a higher risk of prostate cancer and worse survival than do White men, but it is unclear whether this is because of differences in diagnosis and management. We re-examined these differences in the United Kingdom, where health care is free and unlikely to vary by socioeconomic status.

Methods:

This study is a population-based retrospective cohort study of men diagnosed with prostate cancer with data on ethnicity, prognostic factors, and clinical care. A Delphi panel considered the appropriateness of investigations and treatments received.

Results:

At diagnosis, Black men had similar clinical stage and Gleason scores but higher age-adjusted prostate-specific antigen levels (geometric mean ratio 1.41, 95% confidence interval (95% CI): 1.15–1.73). Black men underwent more investigations and were more likely to undergo radical treatment, although this was largely explained by their younger age. Even after age adjustment, Black men were more likely to undergo a bone scan (odds ratio 1.37, 95% CI: 1.05–1.80). The Delphi analysis did not suggest differential management by ethnicity.

Conclusions:

This UK-based study comparing Black men with White men found no evidence of differences in disease characteristics at the time of prostate cancer diagnosis, nor of under-investigation or under-treatment in Black men.

Trends in distribution and prognostic significance of Gleason grades on radical retropubic prostatectomy specimens between 1989 and 2001

BACKGROUND

The objectives of the current study were to examine time trends in the prevalence of Gleason grades of prostate cancer on radical retropubic prostatectomy (RRP) specimens and to assess the resultant impact on prognosis.

METHODS

The authors examined the prevalence over time of each grade and Gleason score (GS) on RRP specimens from 8750 patients who were treated between 1989 and 2001. Biochemical recurrence-free survival (BRFS), which was estimated by using Kaplan-Meier methodology, was examined in subgroups of patients defined by tumor grade and era of surgery.

RESULTS

The prevalence of Grade 3 prostate cancers increased (86% vs. 49% for primary Gleason grade and 71% vs. 47% for secondary Gleason grade; 1999-2001 vs. 1989-1990, respectively), whereas the prevalence of Grade 2 tumors decreased (0.4% vs. 38% for primary Gleason grade and 1.3% vs. 28% for secondary Gleason grade, respectively) over the study period, leading to fewer GS 4 and 5 tumors and more GS 6 and 7 tumors. BRFS improved over time for patients who had GS 5 tumors (hazards ratio [HR], 0.92 per year; P = .003) and GS 6 tumors (HR, 0.93; P < .001) but remained unchanged for GS 7 tumors (HR 0.99; P = .462) and GS 8-10 tumors (HR 1.02; P = .360). Patients who were treated in the recent era (1997-2001) had greater differentiation of BRFS based on GS or Gleason grade compared with patients who were treated earlier (1989-1991).

CONCLUSIONS

The current results confirmed that there were changes in the prevalence of Gleason grades on RRP specimens between 1989 and 2001. A chronological change in pathologic grading classification is suggested by evolving prognostic implications, which must be accounted for when comparing outcomes from different eras.

Prostate cancer and the Will Rogers phenomenon

BACKGROUND

Information on tumor stage and grade are used to assess cancer prognosis and to produce standardized comparisons of end results over time. Changes in the interpretation of classification schemes can alter the apparent distribution of cancer stage or grade in the absence of a true biologic change. Since the introduction of prostate-specific antigen testing, the reported incidence of low-grade prostate cancer has declined. To determine whether this decline is in part a result of Gleason score reclassification during the same time period, we documented the potential impact of reclassification between 1992 and 2002 on clinical outcomes.

METHODS

A population-based cohort of 1858 men who were < or = 75 years of age at diagnosis of prostate cancer in 1990-1992 was assembled retrospectively from the Connecticut Tumor Registry. Histology slides of the diagnostic prostate tissue were retrieved and reread in 2002-2004 by an experienced pathologist blinded to the original Gleason score readings. Prostate cancer mortality rates for the cohort calculated using the original Gleason score readings were compared with those calculated using the contemporary Gleason score readings. Statistical tests were two sided.

RESULTS

The contemporary Gleason score readings were statistically significantly higher than the original readings (mean score increased from 5.95 to 6.8; difference = 0.85, 95% confidence interval = 0.79 to 0.91; P < .001). Consequently, the Gleason score-standardized contemporary prostate cancer mortality rate (1.50 deaths per 100 person-years) appeared to be 28% lower than standardized historical rates (2.08 deaths per 100 person-years), even though the overall outcome was unchanged. This apparent improvement in mortality held for all Gleason score categories.

CONCLUSIONS

In this population, a decline in the reported incidence of low-grade prostate cancers appears to be the result of Gleason score reclassification over the past decade. This reclassification resulted in apparent improvement in clinical outcomes. This finding reflects a statistical artifact known as the Will Rogers phenomenon.

Trends in Reporting Gleason Score 1991 to 2001: Changes in the Pathologist's Practice

OBJECTIVE

The prostate specific antigen (PSA) era has been associated with a grade migration towards moderately-differentiated (Gleason 5-7) prostate cancer. We investigated whether changes in interpretation of the Gleason system could be a contributing factor by reviewing the Gleason scores for prostate cancer in our region.

PATIENTS AND METHODS

Records of patients with prostate cancer assigned a Gleason score between 1991-2001 were retrospectively reviewed. We analysed trends in Gleason score, method of diagnosis and age at diagnosis. Following this, 50 cases from the dataset were randomly selected (stratified to contain half Gleason 2-4 reports) and reviewed in a blinded manner by an uropathologist and given a new Gleason score.

RESULTS

2737 patients were diagnosed and given a Gleason score; 1484 by prostate biopsy (PB) and 1172 by transurethral resection of prostate (TURP). 273 radical prostatectomy (RP) specimens were received, although the results of pre-operative biopsies were available in only 192 of these patients. Over time, there was an increase in the proportion of patients with Gleason 5-7, and a significant decrease in reporting of Gleason 2-4 cancer (r2 = 0.81, p < 0.0001). In 1991, 24% of cancers were Gleason 2-4; in 2001 this had decreased to 2.4%. TURP was associated with more Gleason 2-4 reports (23%) compared with PB (13.2%) and RP (9.2%). On blinded review, all Gleason 2-4 reports were upgraded to Gleason 5-7 cancer (p < 0.001).

CONCLUSION

Over time, the proportion of Gleason 2-4 prostate cancer reported has significantly decreased. Our study suggests that a change in practice by the pathologist is a significant factor in this grade migration.

Potentially advanced malignancies detected by screening for prostate carcinoma after an interval of 4 years

BACKGROUND

At the Rotterdam branch of the European Randomized Study of Screening for Prostate Cancer, a cohort of 19,970 men ages 55-75 years is screened at an interval of 4 years. Screening includes systematic sextant needle biopsy for men with elevated prostate-specific antigen (PSA) levels and/or positive findings on digital rectal examination or transrectal ultrasound. Detection during the second screening round of a large number of high-grade (Gleason Grade 4 or 5) malignancies and/or a large number of malignancies in general could be considered the result of a failure to identify these malignancies at an early stage, during prevalence screening.

METHODS

Men diagnosed during the second screening round with potentially advanced carcinoma (PAC), characterized by a biopsy Gleason score of 7 (4 + 3, or 3 + 4 with > 30% malignant involvement) or a biopsy Gleason score of 8-10, were identified. Clinical data, including PSA values on prevalence screening, biopsy history, clinical stage, and follow-up data, were retrieved for these patients. Tumor features were further analyzed in radical prostatectomy specimens.

RESULTS

During the second screening round, 503 malignancies, including 30 (6.0%) with features of PAC on diagnostic biopsy, were detected in 11,210 patients. Curative treatment was offered to 26 patients. Prostatectomy demonstrated the presence of organ-confined disease in 11 of 12 specimens, and tumor volume ranged from 0.11-7.93 cm3 (median, 1.05 cm3). PSA failure was noted in 6 of 22 patients who were offered curative therapy.

CONCLUSIONS

PAC is a rare finding in the second round of screening after a 4-year interval, and a substantial proportion of PAC cases detected in the second screening round represent organ-confined disease. The findings of the current study suggest that the screening protocol used is sufficiently effective for detecting > 95% of malignancies before they develop features that would make them incurable.

Prostate cancer grade assignment: the effect of chronological, interpretive and translation bias

PURPOSE

Surveillance, Epidemiology and End Results (SEER) data reveal an increasing incidence in the detection of moderately differentiated prostate cancer and a stable or decreasing incidence in well and poorly differentiated cancer. Plausible reasons for this phenomenon include the decrease in transurethral resections performed and an increase in the number of prostate specific antigen triggered ultrasound guided needle biopsies. We examined additional explanations for the grade shift with time and addresses the impact of this grade shift on clinical end points.

MATERIALS AND METHODS

Archived slides from 100 patients (82 needle biopsy specimens and 18 transurethral resection specimens) treated for prostate cancer between 1975 and 1985 were reexamined. Current grades were assigned using the WHO and the Gleason grading systems, and they were compared with the original grade assignments. Current Gleason score was translated to WHO grade by operational SEER criteria (2 to 4-well, 5 to 7-moderately and 8 to 10-poorly differentiated). Analysis of the 100 specimens by life table methodology calculated cancer specific survival according to the era of grade assignment.

RESULTS

There was significant upward grade migration from the historic to the current WHO grade and from the translation by SEER methodology of the current Gleason score to WHO grade (p <0.0001). Interpretive and chronological bias caused expansion of the moderately differentiated category at the expense of well differentiated cancer and significant deviation in cancer specific survival curves (p <0.013). SEER translation bias resulted in expansion of the moderately differentiated grade category at the expense of poorly differentiated cancer and eliminated the significant difference in cancer specific survival between Gleason 5/6 and 7 (p <0.006).

CONCLUSIONS

Contemporary understanding of Gleason grading has lowered the threshold for assignment to higher grade. While a change in tumor biology may be partially responsible for the trend toward higher grade assignment, grade migration as described is also a significant contributing factor in reported histological trends for newly diagnosed prostate cancer and it significantly compromises efforts at historical comparisons.

The Gleason score shift: score four and seven years ago

PURPOSE

There is some evidence that Gleason scores (GS) have shifted over time, although documentation of the extent to which this has occurred and its clinical significance is sparse.

METHODS AND MATERIALS

Three types of analyses were performed to characterize the GS shift. First, the time-related changes in GS, T-stage category, and PSA for all 983 patients treated with conformal radiotherapy at our institution were examined between 1992 and 1997. Then a matched-pair analysis of patients treated without androgen deprivation was implemented. Patients were matched for grouped GS, grouped PSA, T category, and grouped radiation dose; 242 patients (Cohort 1) treated between 1992 and 1994 were compared to 242 patients treated between 1995 and 1997 (Cohort 2). Follow-up for each patient in Cohort 1 was truncated to match the length of follow-up for his counterpart in Cohort 2 (median follow-up 42 vs. 47 months). The ASTRO consensus definition of a rising PSA was used. Finally, the pathology slides of 106 patients treated with radiotherapy at another institution between 1987 and 1993 underwent a blind second review by one of the study pathologists (P.T.) in 1998.

RESULTS

The percentages of prostate cancer patients treated with radiotherapy at our institution from 1992 to 1994 vs. 1995 to 1997 were GS 2-5: 49% vs. 16%, GS 6: 27% vs. 59%, GS 7: 20% vs. 19%, and GS > or =8: 8.3% vs. 6%. There was no clear difference in T category over time with 92-96% having T1-T2 disease. The percentage of patients with a PSA < or = 10 ng/mL rose rapidly from 35% in 1992 to 63% in 1994. In corroboration of these findings, the pathologic review of specimens from 106 patients at another institution yielded changes between the initial reading to the recent reading of 50% to 6% for GS 2-5, 22% to 31% for GS 6, 16% to 25% for GS 7, and 12% to 25% for GS 8-10 (p < 0.0001). From the matched-pair analysis, 5-year Kaplan-Meier bNED rates were 68% and 82% (p = 0.03) favoring Cohort 2.

CONCLUSIONS

During the study period, pretreatment PSA values declined and T category remained stable; yet, GS increased. Upgrading of GS would be expected to lead to an improvement in outcome for all GS groups because of the Will Rogers effect, which explains in part the results of the matched-pair analysis. The GS shift confounds retrospective series spanning the 1990s.

High Gleason Scores and Lower Prostate-Specific Antigen Levels in a Single Institution Over the Past Decade

Recent trends suggest that carcinoma of the prostate is being detected at earlier stages in its natural history; our objective is to determine if this trend is accompanied by changes in tumor characteristics. Two hundred ninety-three men from 1990-1993, 308 from 1994-1996, and 323 from 1998-2000 with newly diagnosed prostate cancer have been evaluated at the University of Colorado Health Sciences Center. We compared the Gleason score, mean age, and the mean prostate-specific antigen (PSA) among the 3 cohorts. The same pathologist reviewed all the pathology slides. A high Gleason prostate cancer score was defined as > or = 7. One hundred seventy-two patients (53.3%) were found to have a high Gleason score in 1998-2000 compared to 116 patients (39.5%) in 1990-1993; the difference was statistically significant (P = 0.0009, Yates-corrected chi2 test). From 1994-1996, 141 patients (45.7%) had a high Gleason score. The mean PSA in high Gleason score, localized prostate cancer was 7.52 ng/mL (range, 0.9-15.3 ng/mL) in the 1998-2000 group, 9.09 ng/mL (range, 1.7-20 ng/mL) in the 1994-1996 group, and 12.6 ng/mL (range, 3.9-25 ng/mL) in the 1990-1993 group. The difference between these groups was statistically significant (P = 0.000018, one-way analysis of variance test). The mean ages for patients in the 3 cohorts were 64.4, 64.5, and 65.2 years of age for the 1998-2000, 1994-1996, and 1990-1993 groups, respectively (P = 0.702). These data suggest a trend toward the diagnosis of more aggressive prostate cancer, with higher Gleason score, and lower PSA in newly diagnosed patients. Continued screening for prostate cancer is resulting in the diagnosis of more unfavorable cancers.

Diagnostic significance of digital rectal examination and transrectal ultrasonography in men with prostate-specific antigen levels of 4 NG/ML or less

OBJECTIVES

To investigate the usefulness of digital rectal examination (DRE) and transrectal ultrasonography (TRUS) for prostate cancer diagnosis and to propose a diagnostic algorithm for individual-based cancer screening in subjects with prostate-specific antigen (PSA) levels of 4.0 ng/mL or less.

METHODS

Between January 1992 and March 2000, 129 subjects with PSA levels of 4.0 or less and abnormal findings on DRE or TRUS underwent prostate biopsy. The subjects were divided into four groups according to the PSA range: 0 to 0.9 ng/mL, 1.0 to 1.9 ng/mL, 2.0 to 2.9 ng/mL, and 3.0 to 4.0 ng/mL. The reliability of the DRE and TRUS and the clinicopathologic features of prostate cancer were investigated among these four groups.

RESULTS

Of the 129 subjects, 17 (13.2%) patients with prostate cancer were diagnosed. The detection rate was 2.2% (1 of 45), 0% (0 of 27), 20.6% (7 of 34), and 39.1% (9 of 23) in subjects with PSA levels of less than 1.0 ng/mL, 1.0 to 1.9 ng/mL, 2.0 to 2.9 ng/mL, and 3.0 to 4.0 ng/mL, respectively. The proportion of patients with Stage II, III, and IV was 58.8%, 41.2%, and 0%, respectively. The percentage with Gleason scores of 8 to 10 was 17.6%. The detection rate of abnormal findings on DRE and TRUS was 14.4% (13 of 90) and 9.5% (7 of 74), respectively. Adding TRUS to DRE in the screening program of subjects with PSA levels of 2.0 to 4.0 ng/mL, increased the detection rate of prostate cancer to 30.8% (4 of 13).

CONCLUSIONS

Routine prostate biopsy should not be undertaken except for highly suspicious DRE findings in subjects with PSA levels less than 2.0 ng/mL. The additional use of TRUS in subjects with PSA levels of 2.0 to 4.0 ng/mL would improve the sensitivity of prostate cancer detection. The diagnostic algorithm proposed in the present study is useful as a screening method for prostate cancer in subjects with PSA levels of 4.0 ng/mL or less.