1190P - Circulating tumor DNA from the tumor-draining pulmonary vein as a biomarker in resected non-small cell lung cancer

Background

The detection of plasma circulating tumor DNA (ctDNA) is a promising approach for the surveillance of non-small cell lung cancer (NSCLC) after surgical resection. As the low abundance of ctDNA in peripheral blood is currently a limiting factor to detect traceable molecular alterations in resectablecases, we aimed to assess the value of ctDNA collected from tumor-draining vein blood at lung resection.

Methods

A cohort of patients with stage I-IV NSCLC was included in the study. Three blood samples were collected at 2 time points: blood from peripheral vein at resection (pB1), from tumor draining vein at resection (dB), peripheral vein at first radiological follow-up (pB2). Targeted next-generation sequencing (NGS) was performed with the Oncomine Precision Assay on all blood samples and on the resected tumors.

Results

32 consecutive patients who underwent curative anatomical resection of stage I (n=17), II (n=2), III (n=9) and IV (n=4) were included in this study. Oncogenic alterations were detected in 30 out of 32 tumors (93.8%), including KRAS (n=14), EGFR (n=6), TP53 (n=8), BRAF (n=1) and MET (n=1) alterations. In the blood sample pB1, the same molecular alterations as in the tumor were traceable in 3 cases (10.0%). In dB, correspondence was detected in 5 cases (16.7%). Median relapse-free survival (mRFS) was significantly shorter in patients with ctDNA in pB1, when compared to patients without traceable ctDNA in pB1 (pB1^positive: 5 (4-5) months, pB1^negative: 22 (7-29) months, HR, 95% CI: 6.1, 1.4 - 25.9, p=0.014). mRFS was significantly shorter in patients with ctDNA in dB, when compared to patients without (dB^positive: 6 (4-15) months, dB^negative: 22 (7-29) months, HR, 95% CI: 3.8, 1.1 - 13.1, p=0.038). mRFS was significantly shorter in patients with ctDNA in pB2, when compared to patients without in pB2 (pB2^positive: 4 (3-4) months, pB2^negative 22 (7-28) months, HR, 95% CI: 15.3, 2.5 - 92.2, p=0.003).

Conclusions

Despite the low number of cases, using blood from the tumor-draining vein during lung resection might improve the sensitivity of NGS-based detection of ctDNA when compared to peripheral blood.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

I. Schmitt-Opitz.

Funding

Thermo Fisher.

Disclosure

All authors have declared no conflicts of interest.