Novel Methods to Assess Tumor Burden and Minimal Residual Disease in Genitourinary Cancers

Abstract

Background and objective: Advances in molecular diagnostics have ushered in a new era for patients with prostate, renal, and urothelial cancers, with novel radiographic and molecular modalities for the assessment of disease burden and minimal residual disease (MRD). Conventional imaging has a limited threshold for disease detection and is often unable to discern clinically occult disease with varying risks of false-negative or false-positive findings depending on the disease state and type of imaging.

Methods: We provide an overview of emerging radiographic and molecular tools in development within the genitourinary (GU) disease space. A literature review of contemporary basic, translational, and clinical research studies was performed, covering the timeframe of 1980-2024 through the MEDLINE (via PubMed) and Scopus databases. We highlight select examples of emerging technologies and biomarker-informed clinical trials, which aim to quantify disease at lower thresholds and have the potential for integrating MRD in clinical practice for GU patients.

Key findings and limitations: The development of novel radiotracers, such as prostate-specific membrane antigen or carbonic anhydrase IX, is being evaluated in both clinical practice and trial setting, aiming to change the management of these tumors. Molecular tools including circulating tumor cells and byproducts such as plasma and urine cell-free circulating tumor DNA provide the opportunity for MRD detection. MRD capture on single-cell or cellular byproducts can serve as a conduit for genomic and transcriptomic analyses, providing insight into the molecular underpinnings and clonal evolution of disease.

Conclusions and clinical implications: While the full potential for MRD applications has yet to be realized, we are witnessing the emergence of novel techniques aimed at MRD detection and the rapid development of elegantly designed studies implementing iterative detection of MRD as means to provide biological rationale and tailor therapeutic options in GU tumors.

Keywords: Circulating tumor DNA; Clinical trials; Minimal residual disease; Radiotracers; Tumor response.