Re-evaluating the role of digital rectal examination in prostate cancer diagnosis in the era of modern MRI

Prostate cancer remains one of the most prevalent malignancies affecting men worldwide, with early detection playing a crucial role in improving patient outcomes[1,2]. Traditional diagnostic methods for prostate cancer, such as digital rectal examination (DRE) and prostate-specific antigen (PSA) testing, have been widely used as primary tools for identifying patients at risk [3]. These methods have formed the basis for referral and further investigation in suspected cases. However, the advent of multiparametric magnetic resonance imaging (mpMRI) has introduced a paradigm shift in the diagnostic pathway for prostate cancer, offering superior sensitivity and specificity in detecting clinically significant cancers[4,5]. A recent study by Sajjad et al examined the diagnostic value of the abnormal DRE in the modern MRI-based prostate cancer pathway[6]. The study involved a retrospective review of 158 patients referred for suspected prostate cancer based on an abnormal DRE. Among these patients, 41% had a concurrent increase in PSA levels, and the overall detection rate of clinically significant cancer was 14%. Importantly, in patients with an abnormal DRE but a normal PSA level, the detection rate for clinically significant cancer was only 3%, compared to 29% in those with both abnormal DRE and elevated PSA levels. These findings suggest that combining DRE with PSA testing could enhance the efficiency of prostate cancer diagnosis, supporting the use of PSA to triage patients directly to mpMRI without the need for repeat DRE. Historically, DRE has been the cornerstone of prostate cancer screening, primarily because of its ability to detect palpable abnormalities within the prostate gland. However, its limitations, such as interobserver variability, low sensitivity, and specificity, have long been recognized[7]. Studies have shown that the positive predictive value of DRE ranges between 12-25%, depending on the experience of the clinician and the patient’s PSA levels[8]. While DRE can identify clinically significant cancers, especially when PSA levels are elevated, and it is less effective as a standalone tool in detecting early stage or smaller tumors[9-11]. With the introduction of PSA testing in the 1980s, the combined use of DRE and PSA has become the standard for prostate cancer screening. However, the specificity of PSA alone is suboptimal, leading to unnecessary biopsies and overdiagnosis of indolent cancers[12]. Consequently, the integration of mpMRI has gained traction as a more accurate and less invasive method for evaluating patients with suspected prostate cancer, particularly in cases where PSA levels are elevated[4]. The use of mpMRI in prostate cancer diagnostics has significantly improved the detection and characterization of clinically significant prostate cancer[13,14]. Unlike DRE and PSA, mpMRI offers a noninvasive approach with a higher sensitivity for identifying prostate lesions, which warrants further investigation. Numerous studies have demonstrated that mpMRI-guided biopsy can detect clinically significant cancers with greater accuracy, reducing the need for unnecessary biopsies and minimizing the risk of overdiagnosis[15,16]. A modeling study demonstrated that mpMRI can detect 30% of clinically significant prostate cancers[17]. This advancement has led to the widespread adoption of mpMRI in the diagnostic pathway, allowing for a more targeted approach to biopsy, especially in patients with elevated PSA or abnormal DRE findings. The integration of DRE with PSA testing and mpMRI represents the evolution of the diagnostic pathway for prostate cancer. By using PSA levels to triage patients, clinicians can more effectively determine those who require further evaluation with mpMRI. This approach reduces unnecessary repeat DREs in secondary care, and ensures that patients with a high likelihood of clinically significant cancer are promptly identified and managed. For patients with an abnormal DRE but normal PSA level, mpMRI can serve as a valuable tool for further assessment. Although the detection rate of clinically significant cancers remains relatively low in this group[18]. Implementing a risk-based approach that combines DRE, PSA, and mpMRI results offers a more precise method for identifying high-risk patients, ultimately improving diagnostic accuracy and reducing unnecessary interventions. The integration of DRE, PSA, and mpMRI in prostate cancer diagnostics represents a significant step toward a more efficient and patient-centered approach. However, challenges remain in ensuring that all patients receive appropriate evaluations and that diagnostic pathways are optimized to reduce unnecessary procedures. Further research is needed to validate the findings across diverse populations and healthcare settings, ensuring that the diagnostic pathway remains adaptable and responsive to individual patient risk profiles. Moreover, advancements in technology, such as artificial intelligence (AI) algorithms, have the potential to further enhance the accuracy of mpMRI interpretation, potentially reducing the reliance on invasive procedures and improving the detection of clinically significant cancers[19]. In conclusion, the role of DRE in prostate cancer diagnosis is evolving, particularly with the advent of mpMRI. Although DRE remains an important tool, its value is significantly enhanced when combined with PSA testing, allowing for a more targeted referral to mpMRI. As the use of mpMRI has become more widespread, integrating DRE and PSA testing into a risk-based model offers a promising approach for optimizing prostate cancer diagnosis and improving patient outcomes.