Prostate Cancer Risk Even with Low PSA: Contemporary Radiological Approaches
Prostate-specific antigen (PSA) levels are a widely used biomarker in prostate cancer screening. However, the diagnostic value of PSA alone is limited by benign prostatic conditions and various physiological factors. Notably, the possibility of clinically significant prostate cancer existing even in individuals with low PSA values remains a significant discussion point in contemporary oncological approaches. This arises from the heterogeneous nature of prostate cancer and the fact that PSA levels do not always correlate directly with tumour burden or aggressiveness.
Cases presenting with low PSA levels but in fact harbouring aggressive prostate cancer can be termed "hidden cancer" in clinical practice. This misleading situation can stem from various factors, such as the tumour being located in the anterior part of the prostate, tumour cells having a low PSA-producing capability, or the patient using certain medications (e.g., 5-alpha reductase inhibitors) that reduce PSA levels. Overlooking these cases can lead to diagnosis at advanced stages of the disease and a worsening prognosis. Consequently, the need for more advanced and precise diagnostic methods, moving beyond sole reliance on PSA values, has become imperative.
To overcome these diagnostic challenges, Multiparametric Magnetic Resonance (mpMR) imaging is now considered one of the gold standards in prostate cancer diagnosis. mpMR not only reveals the anatomical structure of the prostate but also provides revolutionary information for characterizing suspicious lesions by evaluating different sequences together, such as T2-weighted images (anatomy and zonal architecture), diffusion-weighted images (DWI) (cell density and mobility), and dynamic contrast-enhanced images (DCE) (vascularization and perfusion).
Thanks to the detailed information provided by mpMR, the detection rate of clinically significant cancers has increased significantly. Particularly, the detection of anteriorly located or small lesions and the targeted approach to biopsy decisions offer much superior accuracy compared to traditional random biopsies. This reduces the number of unnecessary biopsies while optimizing the diagnosis of high-grade cancers.
The integration of mpMR findings with biopsy is made possible by advanced technological approaches, particularly the 3-point volumetric fusion algorithm. This algorithm precisely merges mpMR images with real-time ultrasound images, allowing radiologists and interventional radiologists to directly target suspicious lesions with millimeter accuracy. Unlike traditional blind or systematic biopsies, fusion biopsy offers a distinct advantage in detecting clinically significant cancers that are at high risk of being missed.
The clinical practice guidelines and current findings from the Turkish Society of Interventional Radiology (TGRD) support the critical role of the 3-point volumetric fusion algorithm. Specifically, in a prostate-specific three-dimensional coordinate system, the localization of suspicious areas identified by MR imaging with millimeter precision using transrectal ultrasonography significantly increases diagnostic efficiency. This method has been observed to considerably enhance diagnostic success, especially in detecting cancers with high Gleason scores that are small in volume or located in difficult-to-access areas. This allows patients to be spared unnecessary biopsy burdens and enables accurate diagnosis at an early stage.
In conclusion, even when PSA levels are low, if clinical suspicion persists, advanced imaging and interventional radiology techniques such as Multiparametric MR and the 3-point volumetric fusion algorithm are indispensable tools for the early and accurate diagnosis of prostate cancer. As an Interventional Radiology specialist, I aim to provide our patients with the most accurate diagnosis and a personalized treatment pathway by utilising these technological advancements. The critical impact of early diagnosis on the course of the disease and treatment success should not be underestimated. For detailed information, please contact Prof. Dr. Aykut Recep Aktaş.