Prostate Cancer: Epidemiology, Risk Factors, and Screening

Prostate cancer is one of the most commonly diagnosed cancers in men worldwide and a leading cause of cancer death in men. Most cases are adenocarcinomas arising in the peripheral zone of the prostate. Its natural history is highly variable: many tumours are indolent and never threaten life, while a minority are aggressive, a heterogeneity that lies at the heart of long-standing debates about screening with the prostate-specific antigen (PSA) test.

Definition

Prostate cancer is a malignant neoplasm of the prostate gland, most commonly acinar adenocarcinoma, graded histologically (Gleason score / ISUP grade group) and staged using the TNM system.

Scope

This entry covers the descriptive epidemiology of prostate cancer, its established and probable risk factors, the principles of histological grading, and the evidence and controversy surrounding PSA-based screening. It is a reference-educational overview and does not provide diagnostic or treatment recommendations or advice on whether an individual should be screened.

Core questions

• How common is prostate cancer and how does its incidence vary by age, ancestry, and geography?
• What are the established risk factors for prostate cancer?
• What does the randomised evidence show about PSA screening and mortality?
• Why is overdiagnosis a central concern in prostate cancer screening?

Key concepts

• Acinar adenocarcinoma
• Prostate-specific antigen (PSA)
• Gleason score and ISUP grade group
• Overdiagnosis and overtreatment
• Active surveillance (as a management concept)
• Family history and hereditary risk
• Screening trials (ERSPC, PLCO)

Clinical relevance

Because many prostate cancers are slow-growing and would never cause symptoms in a man's lifetime, detecting them through PSA testing can lead to overdiagnosis and treatment of disease that posed no threat, while still potentially reducing deaths from aggressive cancers (Schröder, 2009; Andriole, 2009; Rebello, 2021). This tension is why screening decisions are framed as individualised and preference-sensitive. This entry describes the epidemiology and evidence and is not a basis for individual diagnostic, screening, or treatment decisions.

Epidemiology

Prostate cancer is among the most frequently diagnosed cancers in men globally and a major cause of cancer mortality, with incidence strongly influenced by age and by the intensity of PSA testing in a population (Bray, 2024). Established risk factors include increasing age, family history of prostate cancer, and African ancestry, which is associated with both higher incidence and worse outcomes; certain inherited mutations (e.g., in BRCA2) also raise risk (Rebello, 2021).

Evidence & guidelines

Two large randomised trials shaped the screening debate: the European Randomized Study of Screening for Prostate Cancer (ERSPC) reported a reduction in prostate-cancer mortality with PSA screening (Schröder, 2009), whereas the US Prostate, Lung, Colorectal, and Ovarian (PLCO) trial did not show a clear mortality benefit, in a context of substantial control-group contamination (Andriole, 2009). Reflecting this evidence and the harms of overdiagnosis, the US Preventive Services Task Force recommends individualised, shared decision-making about PSA screening for men aged 55-69 and recommends against routine screening at age 70 and older (USPSTF, 2018). Histological grading and classification follow the WHO scheme and the Gleason/ISUP system (Humphrey, 2016); readers should consult current guidelines.

Debates

Does PSA-based screening reduce prostate-cancer mortality, and is the benefit worth the harms?

The ERSPC trial found a relative reduction in prostate-cancer mortality with screening, while the PLCO trial did not show a clear benefit; both highlight substantial overdiagnosis, so the net value of screening is judged to depend on individual preferences and is addressed through shared decision-making rather than blanket recommendations.

Seminal works

• schroder-2009
• andriole-2009
• rebello-2021
• uspstf-2018

Frequently asked questions

What is overdiagnosis in prostate cancer?

Overdiagnosis refers to detecting, often through PSA testing, cancers that are so slow-growing they would never have caused symptoms or death in a man's lifetime; treating them can cause harm without benefit, which is a central concern in screening.

Did the major screening trials agree on PSA testing?

No. The European ERSPC trial reported reduced prostate-cancer mortality with screening, whereas the US PLCO trial did not show a clear mortality benefit, and this divergence underpins the cautious, individualised approach to PSA screening.