Low prostate-specific antigen and no Gleason score upgrade despite more extensive cancer during active surveillance predicts insignificant prostate cancer at radical prostatectomy

PTEN loss and chromosome 8 alterations in Gleason grade 3 prostate cancer cores predicts the presence of un-sampled grade 4 tumor: implications for active surveillance

Men who enter active surveillance because their biopsy exhibits only Gleason grade 3 (G3) frequently have higher grade tumor missed by biopsy. Thus, biomarkers are needed that, when measured on G3 tissue, can predict the presence of higher grade tumor in the whole prostate. We evaluated whether PTEN loss, chromosome 8q gain (MYC) and/or 8p loss (LPL) measured only on G3 cores is associated with un-sampled G4 tumor. A tissue microarray was constructed of prostatectomy tissue from patients whose prostates exhibited only Gleason score 3+3, only 3+4 or only 4+3 tumor (n=50 per group). Cores sampled only from areas of G3 were evaluated for PTEN loss by immunohistochemistry, and PTEN deletion, LPL/8p loss and MYC/8q gain by fluorescence in situ hybridization. Biomarker results were compared between Gleason score 6 vs 7 tumors using conditional logistic regression. PTEN protein loss, odds ratio=4.99, P=0.033; MYC/8q gain, odds ratio=5.36, P=0.010; and LPL/8p loss, odds ratio=3.96, P=0.003 were significantly more common in G3 cores derived from Gleason 7 vs Gleason 6 tumors. PTEN gene deletion was not statistically significant. Associations were stronger comparing Gleason 4+3 vs 6 than for Gleason 3+4 vs 6. MYC/8q gain, LPL/8p loss and PTEN protein loss measured in G3 tissue microarray cores strongly differentiate whether the core comes from a Gleason 6 or Gleason 7 tumor. If validated to predict upgrading from G3 biopsy to prostatectomy these biomarkers could reduce the likelihood of enrolling high-risk men and facilitate safe patient selection for active surveillance.

The Significance of Accurate Determination of Gleason Score for Therapeutic Options and Prognosis of Prostate Cancer

The Gleason score (GS) to date remains one of the most reliable prognostic predictors in prostate cancer (PCa). However, the majority of studies supporting its prognostic relevance were performed prior to its modification by the International Society of Urological Pathology (ISUP) in 2005. Furthermore, the combination of Gleason grading and nuclear/nucleolar subgrading (Helpap score) has been shown to essentially improve grading concordance between biopsy and radical prostatectomy (RP) specimens. This prompted us to investigate the modified GS and combigrading (Gleason/Helpap score) in association with clinicopathological features, biochemical recurrence (BCR), and survival. Core needle biopsies and corresponding RP specimens from 580 patients diagnosed with PCa between 2005 and 2010 were evaluated. According to the modified GS, the comparison between biopsy and RP samples resulted in an upgrading from GS 6 to GS 7a and GS 7b in 65% and 19%, respectively. Combigrading further resulted in an upgrading from low grade (GS 6/2a) to intermediate grade PCa (GS 6/2b) in 11.1% and from intermediate grade (GS 6/2b) to high grade PCa (GS 7b/2b) in 22.6%. Overall, well-differentiated PCa (GS 6/2a) was detected in 2.8% of RP specimens, while intermediate grade (GS 6/2b and GS 7a/2b) and high grade cancers (≥ GS 7b) accounted for 39.5% and 57.4% of cases, respectively. At a mean follow-up of 3.9 years, BCR was observed in 17.6% of patients with intermediate (9.8%) or high grade PCa (30.2%), while PSA relapse did not occur in GS 6/2a PCa. In conclusion, adding nuclear/nucleolar subgrading to the modified GS allowed for a more accurate distinction between low and intermediate grade PCa, therefore offering a valuable tool for the identification of patients eligible for active surveillance (AS).

Variation in serum prostate-specific antigen levels in men with prostate cancer managed with active surveillance

OBJECTIVE

To describe fluctuations in prostate-specific antigen (PSA) levels in men managed with active surveillance (AS) to determine if a single PSA increase is a consistent measure to use to trigger intervention.

PATIENTS AND METHODS

We evaluated data on 541 patients undergoing AS between 1995 and 2011. PSA variation was described by studying the Kaplan-Meier probability of patients' PSA levels reaching 4 or 7 ng/mL, falling below those thresholds, and then rising to those thresholds again. We also examined PSA variation by calculating the Kaplan-Meier probability of a PSA change followed by an equal or greater change in the opposite direction.

RESULTS

We analysed data on 541 patients undergoing AS with a median (interquartile range [IQR]) of 8 (6-12) PSA measurements and undergoing AS for a median (IQR) of 4 (2-6) years. The 5-year estimate of the probability of reaching a threshold PSA of 7 ng/mL was 40% (95% confidence interval [CI] 35-46%) and the 5-year estimate of subsequently falling below this threshold was 90% (95% CI 82-95%). The 5-year estimate of a PSA direction change was 95% (95% CI 93-97%) overall and 56% (95% CI 51-61%) for PSA direction changes of ≥1 ng/mL.

CONCLUSIONS

We observed a high probability of variability in PSA levels for patients on AS. The probability of changes in PSA, defined by an increase to the specified thresholds or a rise >1 ng/mL within 6 months and subsequent decrease of equal or greater value on a subsequent measurement, increases over time; therefore, a single change in PSA level is not a reliable endpoint for patients on AS.

High risk of under-grading and -staging in prostate cancer patients eligible for active surveillance

Background

Active surveillance (AS) is increasingly offered to patients with low risk prostate cancer. The present study was conducted to evaluate the risk of tumor under-grading and -staging for AS eligibility. Moreover, we analyzed possible biomarkers for predicting more unfavorable final tumor histology.

Methods

197 patients who underwent radical prostatectomy (RPE) but would have met the EAU (European Association of Urology) criteria for AS (PSA<10 ng/ml, biopsy GS ≤6, ≤2 cancer-positive biopsy cores with ≤50% of tumor in any core and clinical stage ≤T2a) were included in the study. These AS inclusion parameters were correlated to the final histology of the RPE specimens. The impact of preoperative PSA level (low PSA ≤4 ng/ml vs. intermediate PSA of >4–10 ng/ml), PSA density (<15 vs. ≥ 15 ng/ml) and the number of positive biopsy cores (1 vs. 2 positive cores) on predicting upgrading and final adverse histology of the RPE specimens was analyzed in uni- and multivariate analyses. Moreover, clinical courses of undergraded patients were assessed.

Results

In our patient cohort 41.1% were found under-graded in the biopsy (final histology 40.1% GS7, 1% GS8). Preoperative PSA levels, PSA density or the number of positive cores were not predictive for worse final pathological findings including GS >6, extraprostatic extension and positive resection margin (R1) or correlated significantly with up-grading and/or extraprostatic extension in a multivariate model. Only R1 resections were predictable by combining intermediate PSA levels with two positive biopsy cores (p = 0.004). Sub-analyses showed that the number of biopsy cores (10 vs. 15 biopsy cores) had no influence on above mentioned results on predicting biopsy undergrading. Clinical courses of patients showed that 19.9% of patients had a biochemical relapse after RPE, among all of them were undergraded in the initial biopsy.

Conclusion

In summary, this study shows that a multitude of patients fulfilling the criteria for AS are under-diagnosed. The use of preoperative PSA levels, PSA density and the number of positive cores were not predictable for undergrading in the present patient collective.

Serum prostate-specific antigen (PSA) concentration is positively associated with rate of disease reclassification on subsequent active surveillance prostate biopsy in men with low PSA density

OBJECTIVE

To investigate the association between serum prostate-specific antigen (PSA) concentration at active surveillance (AS) entry and disease reclassification on subsequent AS biopsy ('biopsy reclassification') in men with low PSA density (PSAD). To investigate whether a clinically meaningful PSA threshold for AS eligibility/ineligibility for men with low PSAD can be identified based on risk of subsequent biopsy reclassification.

PATIENTS AND METHODS

We included men enrolled in the Johns Hopkins AS Study (JHAS) who had a PSAD of <0.15 ng/mL/g (640 men). We estimated the incidence rates (IRs; per 100 person years) and hazard ratios (HR) of biopsy reclassification (Gleason score ≥ 7, any Gleason pattern 4 or 5, ≥3 positive cores, or ≥50% cancer involvement/biopsy core) for categories of serum PSA concentration at the time of entry into AS. We generated predicted IRs using Poisson regression to adjust for age and prostate volume, mean percentage free PSA (ratio of free to total PSA) and maximum percentage biopsy core involvement with cancer.

RESULTS

The unadjusted IRs (per 100 person years) of biopsy reclassification across serum PSA concentration at entry into JHAS showed, in general, an increase; however, the pattern was not linear with higher IRs in the group ≥ 4 to <6 ng/mL (14.2, 95% confidence interval [CI] 11.8-17.2%) when compared with ≥6 to <8 ng/mL (8.4, 95% CI 5.7-12.3%) but almost similar IRs when compared with the group ≥ 8 to <10 ng/mL (14.8, 95% CI 8.4-26.1%). The adjusted predicted IRs of reclassification showed a similar non-linear increase in IRs, whereby the rates around 4 ng/mL were similar to the rates around 10 ng/mL.

CONCLUSION

Risk for biopsy reclassification increased non-linearly across PSA concentration in men with low PSAD, whereby no obvious clinically meaningful threshold could be identified. This information could be incorporated into decision-making for AS. However, longer follow-up times are needed to warrant final conclusions.