Prostate-specific antigen velocity in a prospective prostate cancer screening study of men with genetic predisposition

BACKGROUND

Prostate-specific antigen (PSA) and PSA-velocity (PSAV) have been used to identify men at risk of prostate cancer (PrCa). The IMPACT study is evaluating PSA screening in men with a known genetic predisposition to PrCa due to BRCA1/2 mutations. This analysis evaluates the utility of PSA and PSAV for identifying PrCa and high-grade disease in this cohort.

METHODS

PSAV was calculated using logistic regression to determine if PSA or PSAV predicted the result of prostate biopsy (PB) in men with elevated PSA values. Cox regression was used to determine whether PSA or PSAV predicted PSA elevation in men with low PSAs. Interaction terms were included in the models to determine whether BRCA status influenced the predictiveness of PSA or PSAV.

RESULTS

1634 participants had ⩾3 PSA readings of whom 174 underwent PB and 45 PrCas diagnosed. In men with PSA >3.0 ng ml-l, PSAV was not significantly associated with presence of cancer or high-grade disease. PSAV did not add to PSA for predicting time to an elevated PSA. When comparing BRCA1/2 carriers to non-carriers, we found a significant interaction between BRCA status and last PSA before biopsy (P=0.031) and BRCA2 status and PSAV (P=0.024). However, PSAV was not predictive of biopsy outcome in BRCA2 carriers.

CONCLUSIONS

PSA is more strongly predictive of PrCa in BRCA carriers than non-carriers. We did not find evidence that PSAV aids decision-making for BRCA carriers over absolute PSA value alone.

An examination of the dynamic changes in prostate-specific antigen occurring in a population-based cohort of men over time

OBJECTIVE

• To determine whether prostate-specific antigen velocity (PSA-V), PSA doubling time (PSA-DT), or PSA percentage change (PSA-PC) add incremental information to PSA alone for community-based men undergoing prostate cancer (PCa) screening.

PARTICIPANTS AND METHODS

• A population-based cohort of 11 872 men from Olmsted County, MN undergoing PSA screening for PCa from 1993 to 2005 was analysed for PSA, PSA-DT, PSA-PC and PSA-V and subsequent PCa. • Receiver-operating characteristics curves and logistic regression were used to calculate the area under the curve (AUC) and Aikaike's information criterion. • Reclassification analysis was performed and the net reclassification improvement and integrated discrimination improvement were measured. • The method of Begg and Greenes was used to adjust for verification bias.

RESULTS

• The single best predictor of future PCa was PSA (AUC = 0.773) with PSA-V (AUC = 0.729) and PSA-DT/PSA-PC (AUC = 0.689) performing worse. • After age adjustment, combining PSA with PSA-V (AUC = 0.773) or PSA-DT/PSA-PC (AUC = 0.773) resulted in no better predictions than PSA alone. • Reclassification analysis showed that adding PSA-V or PSA-DT/PSA-PC to PSA did not result in a meaningful amount of reclassification.

CONCLUSIONS

• PSA is a better predictor of future PCa than PSA-V, PSA-DT, or PSA-PC. • Adding PSA-V, PSA-DT, or PSA-PC to PSA does not result in clinically relevant improvements in the ability to predict future PCa.

Oral selenium supplementation has no effect on prostate-specific antigen velocity in men undergoing active surveillance for localized prostate cancer

The Nutritional Prevention of Cancer trial showed a 52% lower incidence of prostate cancer in men supplemented with selenium. As a result, our study was designed to assess whether selenium supplementation attenuates the progression of prostate cancer. A phase 2 randomized, double-blind, placebo-controlled clinical trial was conducted in men with localized nonmetastatic prostate cancer who had elected to forgo active treatment and be followed by active surveillance. A total of 140 men were randomized to placebo (n = 46), 200 microg/d (n = 47), or 800 microg/d (n = 47) selenium p.o. (as selenized yeast) and followed every 3 months for up to 5 years. Prostate-specific antigen (PSA) velocity was used as a marker of prostate cancer progression and was estimated using mixed-effects regression. Adjusting for age, body mass index, baseline selenium, smoking, baseline PSA, race, PSA method, and Gleason score, PSA velocities for the 200 microg/d and 800 microg/d treatment groups were not statistically significantly different from placebo (P = 0.32 and P = 0.61, respectively). In the highest quartile of baseline selenium, men supplemented with 800 microg selenium showed statistically significantly higher PSA velocity as compared with placebo (P = 0.018). Selenium supplementation did not show a protective effect on PSA velocity in subjects with localized prostate cancer. On the contrary, supplementation with high-dose selenium was observed to be a risk factor for increased PSA velocity in men with high baseline plasma selenium concentrations.

Effect of aspirin, other NSAIDs, and statins on PSA and PSA velocity

BACKGROUND

Aspirin, other non-steroidal anti-inflammatory drugs (NSAIDs), and statins have been associated with lower risk of prostate cancer and its progression, though results have been inconsistent.

METHODS

Data from 140 men with prostate cancer enrolled in a Phase 2 clinical trial of selenium to prevent prostate cancer progression were analyzed to determine association between aspirin, other NSAIDs, or statin use with baseline serum prostate-specific antigen (PSA) levels and PSA velocity (rate of PSA change over time) using repeated measures over an average follow-up time of 3.2 years. Multiple linear regression and mixed effects models were used to model the association of medication use with PSA at baseline and with PSA velocity, respectively.

RESULTS

Baseline PSA levels were significantly lower in aspirin users compared to non-users (5.17 ng/ml vs. 7.58 ng/ml, P = 0.001). This association was statistically significant in never smokers (aspirin users vs. non-users: 4.19 ng/ml vs. 8.24 ng/ml, P = 0.004) but not in ever smokers (aspirin users vs. non-users: 5.52 ng/ml vs. 7.3 ng/ml, P = 0.101). Statin and other NSAID use was not associated with baseline PSA. Aspirin, statin, or other NSAID use at baseline demonstrated a non-significant negative association with PSA velocity.

CONCLUSION

These findings support an effect of aspirin use on PSA, particularly among never smokers. However, they do not suggest a protective effect on the disease and support previous findings that aspirin use may mask accurate measurement of PSA warranting consideration of washout procedures prior to testing.

Can prostate specific antigen velocity thresholds decrease insignificant prostate cancer detection?

PURPOSE

A controversy of current prostate specific antigen based prostate cancer screening is the over detection of potentially insignificant prostate cancer. Because PSA kinetics were previously linked to prostate cancer specific mortality, we determined whether prostate specific antigen velocity is associated with clinically significant prostate cancer.

MATERIALS AND METHODS

A total of 1,073 men underwent radical prostatectomy from 1992 to 2008 with data available on prostate specific antigen velocity and tumor volume. Insignificant cancer was defined by the Ohori criteria as organ confined, tumor volume 0.5 cc or less and no primary or secondary Gleason pattern 4 or 5. We calculated the proportion of men with pathologically insignificant prostate cancer stratified by prostate specific antigen velocity.

RESULTS

Preoperative prostate specific antigen velocity greater than 0.4 ng/ml per year was significantly associated with high grade disease (p = 0.008), positive surgical margins (p = 0.003) and seminal vesicle invasion (p = 0.007) at radical prostatectomy. Median tumor volume was also significantly higher in men with preoperative prostate specific antigen velocity greater than 0.4 ng/ml per year (3.1 vs 2.4 cc, p = 0.0001). Overall 69 men (6%) met the Ohori criteria for insignificant cancer. Patients with preoperative prostate specific antigen velocity greater than 0.4 ng/ml per year were 50% less likely to have insignificant disease (10% vs 5%, p = 0.003).

CONCLUSIONS

A prostate specific antigen velocity threshold of 0.4 ng/ml per year was associated with the likelihood of insignificant prostate cancer. This suggests that prostate specific antigen velocity may be a useful adjunct in prostate cancer screening to increase specificity for identifying patients with clinically significant disease.