Screening for prostate cancer

Ilic D, O'Connor D, Green S, Wilt TJ

Published Online:

November 10, 2010

Prostate cancer is one of the most prevalent forms of cancer in men worldwide. Screening for prostate cancer requires diagnostic tests to be performed in the absence of any symptoms or indications of disease. These tests include the digital rectal examination (DRE), the prostate-specific antigen (PSA) blood test and the transrectal ultrasound-guided biopsy (TRUS). Screening aims to identify cancers at an early and treatable stage, therefore increasing the chances of successful treatment while also improving a patient's future quality of life. This review identified five relevant studies, comprising of 341,351 participants in total. Two of the studies were assessed to be of low risk of bias, whilst the remaining three had methodological weaknesses. Meta-analysis of the five included studies demonstrated no statistically significant reduction in prostate cancer-specific mortality (RR 0.95, 95% CI 0.85 to 1.07). Only a preplanned analysis of a 'core' age group of men from the largest study included in this review reported a significant 20% relative reduction in prostate cancer-specific mortality. Among this 'core' group of men aged 55 to 69 the ERSPC authors report that 1410 men would need to be screened to prevent one additional death from prostate cancer during a 9-year period, which is also associated with 48 men needing to be treated for prostate cancer (RR 0.80, 95% CI 0.65 to 0.98). Harms included high rates of false-positive results for the PSA test (up to 75.9%), infection, bleeding, and pain associated with subsequent biopsy.

Abstract (click to read)

Background:

Any form of screening aims to reduce disease specific and overall mortality and improve a person's future quality of life. Screening for prostate cancer has generated considerable debate within the medical and broader community, as demonstrated by the varying recommendations made by medical organizations and governed by national policies. Much of this debate is due to the limited availability of high quality research and the influence of false-positive or false-negative results generated by use of the screening techniques such as the digital rectal examination (DRE) and prostate-specific antigen (PSA) blood test. Our 2006 Cochrane review identified insufficient evidence to either support, or refute, the use of routine mass, selective or opportunistic screening for prostate cancer. This article is an update of that review.

Objectives:

To determine whether screening for prostate cancer reduces prostate cancer-specific mortality, all-cause mortality, and its impact on quality of life, including adverse events.

Search strategy:

An updated search of electronic databases (PROSTATE register, CENTRAL the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, CANCERLIT and the NHS EED) was performed, in addition to hand searching of specific journals and bibliographies in an effort to identify both published and unpublished trials.

Selection criteria:

All randomised controlled trials (RCTs) of screening versus no screening for prostate cancer were eligible for inclusion in this review.

Data collection and analysis:

The original search (2006) identified 99 potentially relevant articles that were selected for full text review. From these citations, two RCTs were identified as meeting the inclusion criteria. In this updated version of the review, the updated search identified a further 106 potentially relevant articles. From these 106 citations, a further 3 RCTs were identified as meeting the inclusion criteria. Data from the trials were independently extracted by two authors.

Main results:

Five RCTs with a total of 341,351 participants were included in this review. All involved PSA testing, though the interval and threshold for further evaluation varied across trials. The age of participants ranged from 50 to 74 years and duration of follow up from 7 to15 years. The methodological quality of three of the studies was assessed as posing a high risk of bias. Our analysis of the five studies showed no statistically significant reduction in prostate cancer-specific or all-cause mortality among the whole population of men randomised to screening versus controls. A preplanned analysis of a 'core' age group of men aged 55 to 69 from the largest trial (ERSPC) reported a significant 20% relative reduction in prostate cancer-specific mortality; (95% CI 0.65 to 0.98) (ARR = 0.71 per 1000 men). Meta-analysis of the five included studies indicated no statistically significant difference in prostate cancer-specific mortality between men randomised to screening and control (RR 0.95, CI 0.85 to 1.07). Sub-group analyses indicated that prostate cancer-specific mortality was not affected by age at which participants were screened. Meta-analysis of two studies investigating all-cause mortality did not determine any significant differences between men randomised to screening or control (RR 1.00, 95% CI 0.98 to 1.02). A diagnosis of prostate cancer was significantly greater in men randomised to screening, compared to those randomised to control (RR 1.35, 95% CI 1.06 to 1.72). None of the studies provided detailed assessment of the effect of screening on quality of life or costs associated with screening. Harms of screening included high rates of false-positive results for the PSA test (up to 75.9%), over-diagnosis (up to 50% in the ERSPC study) and adverse events associated with transrectal ultrasound (TRUS) guided biopsies such as infection, bleeding and pain.

Authors' conclusions:

Prostate cancer screening did not significantly decrease prostate cancer-specific mortality in a combined meta-analysis of five RCTs. Only one study (ERSPC) reported a benefit in a subgroup of men aged 55 to 69. Within this subgroup of men it was determined that 1410 men needed to be invited to screening and 48 additional men subsequently diagnosed with prostate cancer needed to receive early intervention to prevent one additional prostate cancer death at 10 years. Men should be informed of this and the demonstrated adverse effects when deciding whether or not to undertake screening for prostate cancer. Any benefits from prostate cancer screening may take up to 10 years to accrue; therefore, men who have a life expectancy less than 10 to 15 years should be informed that screening for prostate cancer is unlikely to be beneficial.

This record should be cited as:

Ilic D, O'Connor D, Green S, Wilt TJ. Screening for prostate cancer. Cochrane Database of Systematic Reviews 2006, Issue 3. Art. No.: CD004720. DOI: 10.1002/14651858.CD004720.pub2

Assessed as up to date:

June 10, 2009

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Primary Review Group:

Prostatic Diseases and Urologic Cancers Group

Health topics:

Urology > Cancer > Prostate

Cancer > Prostate

Cancer > Screening

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