Minimally Invasive Real-Time Detection of Actionable Mutations in Patients With Metastatic Solid Tumors Using Fine-Needle and Liquid Biopsies.

Purpose: Fine-needle biopsy (FNB) and liquid biopsy are minimally invasive methods of tumor sampling that provide feasible means to assess tumor genotypes in real time. However, more data are needed to establish the strength of these methods by benchmarking against the current gold standard methods, core-needle biopsy (CNB) or surgical excision of the tumor.
Patients and Methods: Eligible patients with advanced solid tumors were prospectively recruited. We performed mutation profiling using matched tumor DNA obtained by CNB, FNB and liquid biopsy, and matrix-assisted laser desorption/ionization time-of-flight custom mass-spectrometry or targeted next-generation DNA sequencing. The actionability of detected mutations was determined using the OncoKB Web tool. Agreement between mutations detected in CNBs, FNBs, and circulating tumor DNA (ctDNA) was examined.
Results: Forty-one patients underwent tumor biopsy. Thirty CNBs (73%) and 34 FNBs (83%) had sufficient tumor and DNA for mutation profiling. Median DNA yield from CNB and FNB were 775 ng (interquartile range, 240 to 347 4ng) and 649 ng (interquartile range, 180 to1350 ng), respectively. Of 29 CNB/FNB pairs available for comparison, actionable mutation results were concordant in 28 (96%). Six of nine actionable mutations (67%) that were found by CNB, FNB, or both were detectable in ctDNA. Two additional actionable mutations were found exclusively in ctDNA.
Conclusion: Optimally processed FNB and liquid biopsy can be used routinely for tumor mutation profiling to identify actionable mutations.