Plasma-Based Genotyping in Advanced Solid Tumors: A Comprehensive Review

Longitudinal ctDNA profiling in precision oncology and immunο-oncology

Serial analysis of circulating tumor DNA (ctDNA) over the disease course is emerging as a prognostic, predictive and patient-monitoring biomarker. In the metastatic setting, several multigene ctDNA assays have been approved or recommended by regulatory organizations for personalized targeted therapy, especially for lung cancer. By contrast, in nonmetastatic disease, detection of ctDNA resulting from minimal residual disease (MRD) following multimodal treatment with curative intent presents major technical challenges. Several studies using tumor genotyping-informed serial ctDNA profiling have provided promising findings on the sensitivity and specificity of ctDNA in predicting the risk of recurrence. We discuss progress, limitations and future perspectives relating to the use of ctDNA as a biomarker to guide targeted therapy in metastatic disease, as well as the use of ctDNA MRD detection to guide adjuvant treatment in the nonmetastatic setting.

Single whole genome sequencing analysis blazes the trail for precision medicine

As precision oncology evolves toward developing more targeted therapies, sequencing has moved to the forefront of treatment decision-making. Whole genome sequencing (WGS) has emerged as a technology capable of identifying candidates for rare and targeted treatments. Yet, because the tumor is constantly evolving during relapse and therapy resistance, the frequency with which WGS should be performed to identify potential new therapies for progressing patients remains unknown. A recent study in Nature Medicine by Van de Haar et al. observed a remarkably stable driver gene mutational profile among 250 biopsy pairs from 231 patients undergoing standard of care treatments during the biopsy interval. Their findings suggest that the actionable metastatic cancer genome is relatively stable over time and that a single WGS provides a complete view of the treatment opportunities available to most metastatic cancer patients.