Image guidance in the focal treatment of prostate cancer

Abstract

Purpose of Review The advent of PSA screening has led to a 7-fold increase in the incidence of prostate cancer (PCa) without a resultant decrease in mortality rate. This has led to the belief that urologists are over-detecting and over-treating the clinically insignificant disease. To maintain the delicate balance between high cancer cure rate and overtreatment, which could potentially lead to unnecessary morbidities, focal therapy (FT) has emerged as the reasonable “middle ground.” In this article, we present the conceptual basis and the challenges of FT, while emphasizing the critical role of imaging in focal treatment of prostate cancer. Recent Findings Multiple phase I trials have demonstrated the feasibility, short-term efficacy, and safety of FT. Fundamental to the success of these trials and the ultimate acceptance of FT is the integral role of imaging in optimal patient selection. Among the different imaging modalities, only ultrasound and multiparametric MRI (mpMRI) are intimately involved in the detection, diagnosis, staging, and treatment of PCa. Each modality has its own unique advantages and shortcomings. Recent advances in enhanced ultrasound modalities (EUSMs), functional MRIs, and biopsy platforms have taken FT one step closer to becoming the standard of care. Summary Although early results of phase I FT trials are encouraging, long-term oncological outcomes remain to be elucidated. Incorporation of these technological advances into large prospective trials is needed to establish FT as an important asset in the urologist’s armamentarium against prostate cancer.

Can Magnetic Resonance-Ultrasound Fusion Biopsy Improve Cancer Detection in Enlarged Prostates?

“…However, these small lesions most likely do not represent clinically significant prostate cancer. 29,30 Lastly, MP-MRI and MR-US fusion technology requires a high initial investment and technical support. As the technology becomes more readily available, costs may decrease.…”

Magnetic resonance imaging (MRI)‐guided transurethral ultrasound therapy of the prostate: a preclinical study with radiological and pathological correlation using customised MRI‐based moulds

“…In fact, up to 75% of patients are found to have localised disease . Current whole‐gland therapy offers the highest oncological efficacy in exchange for significant morbidities, which has motivated a growing interest in focal or regional treatment strategies that can achieve comparable oncological efficacy with minimal adverse effects on sexual and urinary function . Multiple phase I focal therapy trials, predominantly using cryotherapy, have shown the feasibility, safety, short‐term oncological control, and minimal adverse effects profile .…”

Considerations for patient selection for focal therapy

“…Transperineal prostate biopsy using a template-guided approach was the agreed upon standard to qualify a patient for focal therapy, though what constitutes acceptable biopsy findings was not defined by the panel [Gravas et al 2012]. There was also an overall agreement that multiparametric functional magnetic resonance imaging (MRI) and new transrectal ultrasound (TRUS) techniques show promising results in relation to characterizing men with prostate cancer and localizing their tumor, but that the exact role for patient selection needs to be further elucidated through multicenter studies [Hoang et al 2012]. …”