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Steven R. Olsen
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MA23 - Early Stage Lung Cancer: Present and Future (ID 926)
- Event: WCLC 2018
- Type: Mini Oral Abstract Session
- Track: Treatment of Early Stage/Localized Disease
- Presentations: 1
- Moderators:
- Coordinates: 9/26/2018, 10:30 - 12:00, Room 105
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MA23.02 - Circulating Tumor DNA Analysis with a Novel Variant Classifier for Recurrence Detection in Resected, Early-Stage Lung Cancer (ID 13498)
10:35 - 10:40 | Author(s): Steven R. Olsen
- Abstract
- Presentation
Background
ctDNA is a blood-based biomarker with promising potential in lung cancer for minimal residual disease (MRD) assessment and early detection of recurrence. However, data regarding feasibility are limited, especially for stage I-II disease.
a9ded1e5ce5d75814730bb4caaf49419 Method
We performed longitudinal plasma ctDNA profiling of early-stage lung cancer patients (pts) that underwent resection at MD Anderson Cancer Center from Apr 2016 to Jan 2017. Plasma ctDNA was analyzed from pre-operative and multiple post-operative time points until disease recurrence. ctDNA profiling was performed using a 30kb Digital Sequencing panel (Guardant Health) covering SNVs in 21 genes and indels in 9 genes that are commonly present in lung cancer. ctDNA profiles from ~30,000 lung cancer pts were used to train a classifier to exclude non-tumor related mutations.
4c3880bb027f159e801041b1021e88e8 Result
A total of 40 pts were included in this analysis, comprised of the first 17 pts with recurrence in the longitudinal study and 23 consecutive pts without recurrence. This cohort was primarily stage I and II (15 [38%], 16 [40%]). Histology included adenocarcinoma (29 [73%]), SCC (6 [15%]), and SCLC (2 [5%]). 58% had adjuvant therapy. Median follow-up was 17.7 (3.4 – 24.5) months and median time to recurrence was 7.1 (3.4 – 16.5) months in this selected cohort. At least one ctDNA alteration was detected in 55% (21/38) of pts with evaluable pre-op samples and in 22% (8/37) of pts at 4 weeks post-op. Presence of ctDNA at 4 weeks post-op heralded eventual recurrence with 43% sensitivity and 91% specificity (75% PPV, 73% NPV) and was significantly associated with worse recurrence free survival (p=0.022, HR 6.52; 95% CI 1.3 – 32.6), while also accounting for stage. In the absence of the variant classifier, an additional 7/37 pts had non-tumor alterations detected at 4 weeks post-op with a recurrence sensitivity and specificity of 57.1% and 69.6%. ctDNA was identified in 76% (13/17) of pts prior to or at the time of recurrence. The median interval between ctDNA detection and radiographic recurrence was 91 days.
8eea62084ca7e541d918e823422bd82e Conclusion
Detection of post-op ctDNA, as early as 4 weeks after resection of early-stage lung cancer, is associated with significantly increased risk of recurrence. Accurate detection of ctDNA in this MRD setting is enabled by a highly sensitive sequencing platform that incorporates a novel variant classifier to enhance clinical specificity.
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P2.03 - Biology (Not CME Accredited Session) (ID 952)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Track:
- Presentations: 1
- Moderators:
- Coordinates: 9/25/2018, 16:45 - 18:00, Exhibit Hall
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P2.03-02 - Cell-Free DNA (cfDNA) Testing in Lung Adenocarcinoma (LUAC) Patients: Spanish Lung Liquid Versus Invasive Biopsy Program (SLLIP) (ID 12561)
16:45 - 18:00 | Author(s): Steven R. Olsen
- Abstract
Background
Liquid biopsies are a revolution in cancer diagnostics as a minimally invasive alternative to tissue biopsy. cfDNA is used for the detection of biomarkers in LUAC patients if a tumor tissue sample is not available. We conducted the SLLIP study to prospectively validate Guardant360 for the detection of 7 targetable activating alterations (EGFR, ALK, ROS1, BRAF, MET, RET, and ERBB2) in LUAC.
a9ded1e5ce5d75814730bb4caaf49419 Method
Blood samples from treatment-naïve stage IIIB-IV LUAC patients were analyzed using Guardant360, a next-generation sequencing panel covering 73 genes. The assay includes complete exon sequencing for 19 cancer genes, sequencing of critical exons in 54 genes, and detection of amplifications (18 genes), fusions (6 genes), and indels (23 genes) with high overall clinical sensitivity rates (85%) and ultra-high specificity (>99.9%). Indels and point mutations can be detected at a mutant allele fraction as low as 0.1%. Guardant360 was compared with tissue genotyping performed as standard of care, using a variety of “real life” techniques. The primary objective was to demonstrate the non-inferiority of Guardant360 versus tissue analysis for the detection of the 7 genetic alterations. The study is registered with ClinicalTrials.gov, number NCT03248089.
4c3880bb027f159e801041b1021e88e8 Result
186 LUAC patients were enrolled over a period of 11 months (August 2016-July 2017). Median age 64, 65% male, 72% smoker/ex-smokers, 85% ECOG performance status 0-1. Targetable activating alterations were detected by the Guardant360 assay and by tissue analysis in 25% (n=47) and 26% (n=49) of patients, respectively (non-inferiority P=0.268). Thirty patients (16%) had alterations identified by both modalities. None of the 186 patients was successfully tested in tissue for all 7 alterations. Of the 17 patients who were negative in tissue but for whom Guardant360 identified targetable alterations, 3 had BRAF V600E mutations. For none of these patients was BRAF tested in tissue. Clinical efficacy per biomarker and treatment modality are awaited.
8eea62084ca7e541d918e823422bd82e Conclusion
Guardant360 cfDNA and tissue analysis detect relevant somatic tumor alterations at similar rates in LUAC patients. Under-genotyping in tissue is common but can be mitigated by the use of cfDNA next generation sequencing assays.
6f8b794f3246b0c1e1780bb4d4d5dc53
