(UroToday.com) Comprehensive genomic profiling by next-generation sequencing of circulating tumor DNA (ctDNA) from plasma provides a minimally invasive method to identify targetable genomic alterations and resistance mechanisms in patients with metastatic castration-resistant prostate cancer (mCRPC). However, the circulating tumor fraction in patients with mCRPC and the clinical validity of genomic alterations detected in plasma remains unknown. At the 2021 GU ASCO meeting, Hanna Tukachinsky and colleagues presented the results of their study evaluating the landscape of genetic alterations using ctDNA-based comprehensive genomic profiling and assessed concordance with tissue-based comprehensive genomic profiling.