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Jun Huang
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P07 - Early Stage/Localized Disease - Imaging and Biomarkers (ID 116)
- Event: WCLC 2020
- Type: Posters
- Track: Early Stage/Localized Disease
- Presentations: 1
- Moderators:
- Coordinates: 1/28/2021, 00:00 - 00:00, ePoster Hall
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P07.04 - Using ctDNA to Detect Minimal Residual Disease after Surgery in Resectable Lung Cancer (ID 1775)
00:00 - 00:00 | Presenting Author(s): Jun Huang
- Abstract
Introduction
ctDNA is a blood-based biomarker with promising potential in lung cancer for minimal residual disease (MRD) assessment and early detection of recurrence. However, there are few studies about ctDNA in postoperative monitoring for resectable lung cancer.
Methods
We retrospectively analyzed paired surgical tissues and postoperative ctDNA next-generation sequencing (NGS) results from 49 lung cancers patients (pts) who underwent surgery. We used 1021-gene panel to assess the genetic variations. ctDNA positive defined as at least one mutation from tissue was detected in postoperative plasma. The cutoff value of TMB-H/L in tissue samples was 9.0 Muts/Mb.
Results
A total of 49 pts included in this analysis with median age 59 (range 37-76), 30 were males. Histologically contained 47 adenocarcinoma, 1 squamous cell carcinoma, 1 LCNEC, and 1 SCLC. One patient had simultaneous multiple primary lung adenocarcinoma and squamous cell carcinoma in different left lobes. Tumors were in different stages, 17 were stage I, 17 were stage II, 15 were stage III and 1 was unknown. Genetic variations were found in all tissue samples. TP53 (60%) was the most common gene, followed by EGFR (42%), LRP1B (16%), KRAS (16%), et. And a total of 63 actionable mutations were found in 84.0% (42/50) tissue samples, including EGFR, KRAS, PIK3CA, ALK, RET, ERBB2, et. Meanwhile, 11 (22.9%) were high tumor mutation burden (TMB) in 48 samples which met TMB assessment conditions. Plasma samples were collected within a few weeks after surgery. Postoperative ctDNA positive rate was 26.5% (13/49) in all patients, and 17.6% (3/17) in stage I, 29.4% (5/17) in stage Ⅱ and 33.3% (5/15) in stage Ⅲ. The ctDNA status had no relationship with collection time from surgery. The median mutation number in ctDNA was 2 (range 1-27). ctDNA positive rate was higher in TMB-H group 63.6% (7/11) than TMB-L 13.5% (5/37) (p=0.003). Considering the possible interference caused by the mutation number in tissue, we limited the top10 genes from tissues to analyze ctDNA again. And the result was the same as previous (p=0.027). Interestingly, in the patient with simultaneous adenocarcinoma and squamous cell carcinoma, we found that the six mutations in ctDNA were 100% matched to adenocarcinoma, and very different from squamous cell carcinoma.
Conclusion
CtDNA is a meaningful and feasible biomarker for postoperative monitoring in resectable lung cancer. Moreover, it can identify the source of MRD in multiple primary lung cancer.
