Irish experience suggests benefits of PSA screening

Key Points

Atlanta-Widespread PSA screening appears to lead to improvements in pathologic outcomes, according to a recent study.

The Republic of Ireland witnessed a rapid increase in opportunistic PSA screening about a decade after the U.S. Widespread screening in the U.S. starting in the 1990s means that American urologists are now treating men with prostate cancers at a substantially earlier stage.

In 2005, about 42% of Irish men 50 years of age and older received at least one PSA screening test, a dramatic increase from 3% in 1994.

"When PSA screening is initially introduced into a population, the 'prevalent pool' of advanced, high-risk cancers are largely discovered, ultimately resulting in a shift towards lower stage and grade cancers at diagnosis," Dr. McGuire said. For example, the PSA testing peak in the U.S. in 1992 was followed by an 80% decline in the rate of distant and locally advanced tumors and high-grade disease.

Dr. McGuire and co-authors from several institutions conducted a retrospective chart review of 651 men who underwent radical prostatectomy at a single tertiary referral institution in Ireland between 2000 and 2010. Clinical and pathologic features were compared to a population of 1,302 men treated in the U.S. by a single surgeon (senior author William J. Catalona, MD) over the same 10-year period (after matching on age and year of diagnosis).

A group of 150 American men who underwent prostatectomy during the early PSA era (1990 to 1992) served as a historical comparison.

The mean age of Irish men was 60 years and their median PSA value was 6.7 ng/mL. Overall, two-thirds of Irish men had biopsy Gleason 6 disease, 30% had Gleason 7, and 4% had Gleason 8 to 10.

Increase in biopsy Gleason grade seen

There was a highly significant increase in the biopsy Gleason grade over the study period (p<12 x 10^-6 ) in men who underwent radical prostatectomy: 44% had Gleason 6, 52% had Gleason 7, and 4% had Gleason 8 to 10. There was also a significant increase in prostatectomy Gleason grade over the study period (p<.001).

In comparison to contemporary Americans, patients in Ireland have higher preoperative PSA values (p<.001), more Gleason 7-10 tumors (p=.003), higher median tumor volume (20% versus 8%; p<.0001), and marginally higher stage disease (pT, 20% versus 17%; p=.06) on univariate analysis. Only tumor volume remained significant on multivariate analysis.

Compared to American men from the early U.S. PSA screening era, there were no significant differences except for slightly higher tumor volume in the Irish men, said Dr. McGuire.

"In terms of prostatectomy outcomes and cancer-specific survival figures, we're probably somewhere near where the American men were in the early- to mid-nineties," he said. "We're following the same pattern in PSA screening in Ireland that occurred in the U.S. Screening strikingly decreases the large advanced tumors, leading to a reduction in prostate cancer mortality that we have already seen in American men."

The comparison therefore suggests that widespread screening may facilitate improvement in prostatectomy outcomes, he said.

"Conversely, the increasing frequency of low-risk disease with screening will raise the challenge of effectively managing early-stage prostate cancer without overtreatment."