Abstract
Background/Aims A prostate specific antigen (PSA) level =4 ng/mL has historically been used as a screening threshold to recommend biopsy; however, guidelines have been changing to recommend lower cutoffs (2.5 ng/mL) and incorporate velocity in decisions to refer men to biopsy. Little is known about how physicians and patients respond to elevated PSA tests. Our objective was to examine trends in biopsy practices over the past decade to identify whether there has been a shift towards lowering PSA thresholds for biopsy referral.
Methods We reviewed electronic records, including laboratory results, for 59,764 members of Group Health who received a PSA test between 1998 and 2007. We identified 3 types of follow-up within 12 months of a test: biopsy, urology visit without a biopsy, or additional PSA testing. Log binomial models were used to examine the relative risk of biopsy within 12 months adjusting for covariates and accounting for clustering of repeated tests within subjects.
Results There appeared to be no shift over time towards lower thresholds for biopsy referral, with 3.0% (123/4,156), 3.1% (111/3,528) and 2.6% (91/3,565) of tests with PSA levels between 2.5 and 3.9 ng/ml resulting in biopsy among within 12 months in the calendar periods 1998–2001, 2002–2004, and 2005–2007 respectively, and 2.9% (325/11,249) overall. For tests with PSA =4.0 ng/ml, 29.7% (1,564/5,271), 26.4% (1,024/3,878), and 27.1% (1,027/3,786) resulted in biopsy across the three time periods, respectively, and 28.0% (3,615/12,935) overall. For tests with PSA levels <2.5 ng/ml, the biopsy frequencies were 0.6% (160/28,188), 0.4% (120/27,690), and 0.4% (111/31,307), respectively and 0.4% (391/87,185) overall. Men with PSA levels =4.0 ng/ml who did not undergo biopsy often attended urology visits (38.6%, 4,992/ 12,935). PSA velocity was strongly associated with biopsy, for example, when PSA was below 4.0 ng/ml, a velocity =0.75ng/mL/year was associated with an 8.4 fold increase in biopsy.
Conclusions Biopsy practices following PSA testing have been stable over time in Group Health. As little is known about real-world biopsy patterns, these data should be helpful to other providers and patients who are uncertain about what is considered common practice in an HMO setting.
