Circulating tumor DNA (ctDNA) analysis has been successfully applied to therapy selection and treatment monitoring in advanced cancer patients. However, it is not yet established whether ctDNA can be used clinically for early cancer detection or recurrence prediction in early stage lung cancer patients.
We analyzed pre-operative plasma samples from 55 early stage NSCLC patients (stages I-IIIA) using next-generation sequencing assay incorporating somatic and epigenomic analysis, and a bioinformatic classifier to filter non-tumor derived variants.Cell type Stage Somatic mutation Epigenetic pattern Total number Recurrence+, n (%) Site of recurrence Adenocarcinoma stage 1 ctDNA- methylation- 9 1 (11) Lung n = 17 methylation+ 6 2 (33.3) Stump, bone ctDNA+ 2 1 (50) lung stage 2 ctDNA- methylation- 0 0 (0) n = 2 methylation+ 0 0(0) ctDNA+ 1 1 (100) multiple stage 3 ctDNA- methylation- 0 0 (0) n = 4 methylation+ 2 0 (0) ctDNA+ 2 2 (100) brain, multiple Sqaumous cell carcinoma stage1 ctDNA- methylation- 0 0 (0) n = 7 methylation+ 3 0 (0) ctDNA+ 4 1 (25) multiple stage2 ctDNA- methylation- 0 0 (0) n = 9 methylation+ 0 0 (0) ctDNA+ 9 2 (22.2) multiple, lung stage3 ctDNA- methylation- 0 0 (0) n = 4 methylation+ 1 0 (0) ctDNA+ 3 1 (33.3) Mediastinal LNs
Somatic mutation analysis alone detected ctDNA in 42% (23/55) of patients, whereas combined mutational and epigenomic analysis detected ctDNA in 67% (37/55). ctDNA detection rate varied by pathological subtypes; using combined approach, ctDNA was detected in all squamous cell carcinoma patients, while only 55% (12/22) in adenocarcinoma (ADC) (
Utilizing a plasma-only sequencing assay incorporating somatic genomic and epigenomic analysis, ctDNA detection rate in early stage lung cancer (stage I-III) can far outperform the detection rate of somatic sequence variant detection alone. And, the presence of pre-operative ctDNA in patients with early stage lung adenocarcinoma may identify those who are more likely to have disease recurrence.
Legal entity responsible for the study: Guradant Health, Inc.
Guardant Health, Redwood City, CA, USA.
I. Kim: Full / Part-time employment, Officer / Board of Directors: Guardant Health. M. Shultz: Officer / Board of Directors: Guardant Health. A. Jaimovich: Officer / Board of Directors: Guardant Health. J. Odegaard: Officer / Board of Directors: Guardant health, Inc. S. Olsen: Officer / Board of Directors: Guardant Health, Inc. A. Talasaz: Officer / Board of Directors: Guardant health. J. Kim: Research grant / Funding (self): Guardant health, Inc. All other authors have declared no conflicts of interest.