Our understanding of the screening, prevention and treatment of early prostate cancer is improving. This is a result of new data from clinical trials and the incorporation of efficacy measures based on risk assessment and quality of life (QoL). This review aims to examine completed and ongoing clinical trials that address issues in early prostate cancer, including screening, prevention, treatment, and QoL. Prostate-specific antigen (PSA) testing has a crucial and evolving role in detecting primary prostate cancer, evaluating prevention interventions and assessing the effectiveness of treatment. Questions remain about the optimal PSA parameters appropriate for primary screening and for diagnosing relapse. Emerging and established data provide evidence that early intervention with hormone therapy, either as immediate or adjuvant therapy, delays progression in prostate cancer patients with intermediate or poor prognosis. The impact of therapeutic modality on QoL has become better characterized, as QoL instruments have been developed, validated and applied.