Longer Prostate Ca Screening Intervals for Baseline PSAs less than 3 ng/mL?

In a population-based screening study of nearly 20,000 men in Rotterdam, men with baseline prostate-specific antigen (PSA) levels < 3 ng/mL were at very low risk of developing prostate cancer. Investigators concluded that a baseline PSA of 3 ng/mL is an appropriate minimum cutoff for determining the need for biopsy and that longer intervals between PSA screening may be possible in this group.

The results were presented at the 2011 Genitourinary Cancers Symposium, in Orlando, Florida, by lead investigator Monique Roobol, PhD, an epidemiologist from Erasmus University Medical Center in Rotterdam (Bul et al, abstract 7). The Rotterdam study is part of the European Randomised Study of Screening for Prostate Cancer (ERSPC), a randomized controlled trial running in eight European countries (Belgium, Finland, France, Italy, The Netherlands, Spain, Sweden, and Switzerland).

From November 1993 to December 1999, a total of 42,376 middle-aged and elderly men (55–74 years old) from population registries in the Rotterdam region were randomized to intervention (biopsy for men with initial PSA levels ≥ 3 ng/mL) or a control arm (no biopsy for baseline PSA < 3 ng/mL, but re-evaluation 4 years later). During the first screening round, 19,950 men were screened. Median overall follow-up was 11 years.

A total of 15,758 men (79% of screened group, median age 62.3 years) had an initial PSA < 3 ng/mL. From 1993–2008, there were 915 cases of prostate cancer diagnosed (5.8%) in these men; 169 were determined to have aggressive prostate cancers, but there were only 23 deaths. While overall risk of prostate cancer was low among men with baseline PSAs < 3 ng/mL, prostate cancer risk increased with increasing baseline PSA levels.

Importantly, said Dr. Roobol, in the lowest PSA range (baseline PSA < 1 ng/mL), median time to prostate cancer diagnosis was 8 years; 45% of men aged 55–74 were in this category, so a prolonged screening interval in this group may be feasible.

“I believe this study gives us some confidence that annual PSA screening is going to soon become a thing of the past,” and men with low baseline PSAs (< 2 ng/mL)  “certainly could be considered for substantially longer intervals of PSA screening,” said Nicholas Vogelzang, MD, of US Oncology, during a press briefing.

The GU Symposium is sponsored by ASCO, ASTRO, and the Society of Urologic Oncology of the AUA.