Liquid Biopsies and Molecular Imaging for Precise Cancer Management

In the last years, several body fluid-based tests, able to detect molecular alterations derived from tumors, have been proposed, and numerous others are in continuous development. These tests, commonly referred to as "liquid biopsies," encompass a wide spectrum of diagnostic procedures, such as circulating tumor cells (CTCs), cell-free circulating tumor DNA (ctDNA), circulating tumor-derived exosome, and other biomarkers, whose detection can offer precious information about tumor volume and disease status. Nevertheless, these novel biomarkers have limited sensitivity and specificity when used alone. In this scenario, molecular imaging with positron emission tomography (PET), due to its wide availability and the consolidated role in cancer patients' management, could be coupled with liquid biopsy for cancer characterization, patient stratification, and the early detection of recurrence. In this chapter, we will focus on studies that combine liquid biopsy and PET-based parameters across different cancer types and therapeutic settings.