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The clinical implications of adding plasma-based circulating tumor DNA next-generation sequencing (NGS) to tissue NGS for targetable mutation detection in non-small cell lung cancer (NSCLC) have not been formally assessed. OBJECTIVE To determine whether plasma NGS testing was associated with improved mutation detection and enhanced delivery of personalized therapy in a real-world clinical setting. DESIGN, SETTING, AND PARTICIPANTS This prospective cohort study enrolled 323 patients with metastatic NSCLC who had plasma testing ordered as part of routine clinical management. Plasma NGS was performed using a 73-gene commercial platform. Patients were enrolled at the Hospital of the University of Pennsylvania from April 1, 2016, through January 2, 2018. The database was locked for follow-up and analyses on January 2, 2018, with a median follow-up of 7 months (range, 1-21 months). MAIN OUTCOMES AND MEASURES The number of patients with targetable alterations detected with plasma and tissue NGS; the association between the allele fractions (AFs) of mutations detected in tissue and plasma; and the association of response rate with the plasma AF of the targeted mutations. RESULTS Among the 323 patients with NSCLC (60.1% female; median age, 65 years [range, 33-93 years]), therapeutically targetable mutations were detected in EGFR, ALK, MET, BRCA1, ROS1, RET, ERBB2, or BRAF for 113 (35.0%) overall. Ninety-four patients (29.1%) had plasma testing only at the discretion of the treating physician or patient preference. Among the 94 patients with plasma testing alone, 31 (33.0%) had a therapeutically targetable mutation detected, thus obviating the need for an invasive biopsy. Among the remaining 229 patients who had concurrent plasma and tissue NGS or were unable to have tissue NGS, a therapeutically targetable mutation was detected in tissue alone for 47 patients (20.5%), whereas the addition of plasma testing increased this number to 82 (35.8%). Thirty-six of 42 patients (85.7%) who received a targeted therapy based on the plasma result achieved a complete or a partial response or stable disease. The plasma-based targeted mutation AF had no correlation with depth of Response Evaluation Criteria in Solid Tumors response (r = −0.121; P = .45). CONCLUSIONS AND RELEVANCE Integration of plasma NGS testing into the routine management of stage IV NSCLC demonstrates a marked increase of the detection of therapeutically targetable mutations and improved delivery of molecularly guided therapy.

Purpose The expanding number of targeted therapeutics for non-small cell lung cancer (NSCLC) necessitates real-time tumor genotyping, yet tissue biopsies are difficult to perform serially and often yield inadequate DNA for next-generation sequencing (NGS). We evaluated the feasibility of using cell-free circulating tumor DNA (ctDNA) NGS as a complement or alternative to tissue NGS. Experimental Design 112 plasma samples obtained from a consecutive study of 102 prospectively enrolled patients with advanced NSCLC were subjected to ultra-deep sequencing of up to 70 genes and matched with tissue samples, when possible. Results We detected 275 alterations in 45 genes, and at least one alteration in the ctDNA for 86 of 102 patients (84%), with EGFR variants being most common. ctDNA NGS detected 50 driver and 12 resistance mutations, and mutations in 22 additional genes for which experimental therapies, including clinical trials, are available. While ctDNA NGS was completed for 102 consecutive patients, tissue sequencing was only successful for 50 patients (49%). Actionable EGFR mutations were detected in 24 tissue and 19 ctDNA samples, yielding concordance of 79%, with a shorter time interval between tissue and blood collection associated with increased concordance (p=0.038). ctDNA sequencing identified 8 patients harboring a resistance mutation who developed progressive disease while on targeted therapy, and for whom tissue sequencing wasn’t possible. Conclusions Therapeutically targetable driver and resistance mutations can be detected by ctDNA NGS, even when tissue is unavailable, thus allowing more accurate diagnosis, improved patient management, and serial sampling to monitor disease progression and clonal evolution.

IMPORTANCE Patients with oligometastatic non-small cell lung cancer (NSCLC) may benefit from locally ablative therapy (LAT) such as surgery or stereotactic radiotherapy. Prior studies were conducted before the advent of immunotherapy, and a strong biological rationale for the use of immunotherapy exists in a minimal residual disease state.OBJECTIVE To evaluate whether the addition of pembrolizumab after LAT improves outcomes for patients with oligometastatic NSCLC. DESIGN, SETTING, AND PARTICIPANTSThis single-arm phase 2 trial of pembrolizumab therapy was performed from February 1, 2015, through September 30, 2017, at an academic referral cancer center. The 51 eligible patients enrolled had oligometastatic NSCLC (Յ4 metastatic sites) and had completed LAT to all known sites of disease. Data were analyzed from February 1, 2015, to August 23, 2018.INTERVENTIONS Within 4 to 12 weeks of completing LAT, patients began intravenous pembrolizumab therapy, 200 mg every 21 days, for 8 cycles, with provision to continue to 16 cycles in the absence of progressive disease or untoward toxic effects. MAIN OUTCOMES AND MEASURESThe 2 primary efficacy end points were progression-free survival (PFS) from the start of LAT (PFS-L), which preceded enrollment in the trial, and PFS from the start of pembrolizumab therapy (PFS-P). The study was powered for comparison with historical data on the first efficacy end point. Secondary outcomes included overall survival, safety, and quality of life as measured by the Functional Assessment of Cancer Therapy-Lung instrument.RESULTS Of 51 patients enrolled, 45 (24 men [53%]; median age, 64 years [range, 46-82 years]) received pembrolizumab. At the time of analysis, 24 patients had progressive disease or had died. Median PFS-L was 19.1 months (95% CI, 9.4-28.7 months), significantly greater than the historical median of 6.6 months (P = .005). Median PFS-P was 18.7 months (95% CI, 10.1-27.1 months). Eleven patients died. Overall mean (SE) survival rate at 12 months was 90.9% (4.3%); at 24 months, 77.5% (6.7%). Neither programmed death ligand 1 expression nor CD8 T-cell tumor infiltration was associated with PFS-L. Pembrolizumab after LAT yielded no new safety signals and no reduction in quality of life.

In this prospective study, PRT for recurrent NSCLC is feasible but can be associated with significant toxicity. Providers should remain cautious in reirradiating NSCLC, paying close consideration to tumor volume, location, and relevant dosimetric parameters. Further research is needed for optimal patient selection to improve overall outcomes.