Abstract 2313: Real-world concordance between tumor mutation burden from blood and tissue
Authors: Kim Leeseul , Oh Youjin , Park Jewel , Hong Ilene , Chae Lena , Viveiros Pedro 
Published: April 2023

Abstract
Background: Tissue tumor mutational burden (tTMB) is known to have predictive value for response to immune checkpoint inhibitor treatment of cancer. Utilization of next-generation sequencing of circulating tumor DNA added another data point of blood tumor mutational burden (bTMB). However, the concordance between tTMB and bTMB is not well understood.
Method: A total of 119 patients with solid tumors who had both tTMB and bTMB (collected from 10/2020 to 10/2022) results were included in the analysis. Patients' tTMB and bTMB concordance were analyzed according to the interval between tTMB and bTMB collection, tumor type, and site of tTMB collection using the Pearson correlation coefficient.
Result: Median tTMB was 4.2 mut/Mb and median bTMB was 9.61mut/Mb. bTMB was moderately correlated with tTMB (Pearson r 0.54) in total patient population. The median interval between tTMB and bTMB collection was 27 days (Q1:14, Q3:1834). Concordance did not significantly change when the interval was under 30 days (Pearson r 0.51). Patients with metastatic disease had higher concordance compared to patients without metastasis of cancer (Pearson r 0.58 vs 0.39). bTMB and tTMB were most strongly correlated when tTMB was collected from metastatic lesions (Pearson r 0.92). No significant correlation was observed when tTMB was collected from lymph nodes (Pearson r 0.20). Regarding cancer types, adenocarcinoma of the lung had a moderate correlation between bTMB and tTMB (Pearson r 0.63) while small cell lung cancer did not demonstrate a significant correlation between bTMB and tTMB (Pearson t -0.30).
Correlation between tTMB and bTMB Total study population 119 Interval between bTMB and tTMB collection &lt;30days 64 Pearson R (p value, CI) 0.55 (0.00, 0.41-0.66) Pearson R (p value, CI) 0.52 (0.00, 0.27-0.70) R squared 0.30 R squared 0.27 Patients with metastatic disease 89 Patients without metastatic disease 30 Pearson R (p value, CI) 0.58 (0.00, 0.42-0.70) Pearson R (p value, CI) 0.39 (0.03, 0.04-0.66) R squared 0.33 R squared 0.16 tTMB collected from primary lesion 51 Lung adenocarcinoma 53 Pearson R (p value, CI) 0.52 (0.00, 0.29-0.70) Pearson R (p value, CI) 0.63 (0.00, 0.45-0.77) R squared 0.27 R squared 0.41 tTMB collected from metastatic lesion 29 Lung squamous cell carcinoma 16 Pearson R (p value, CI) 0.92 (0.00, 0.84-0.96) Pearson R (p value, CI) 0.56 (0.02, 0.09-0.82) R squared 0.85 R squared 0.31 tTMB collected from lymph nodes 34 Lung small cell carcinoma 10 Pearson R (p value, CI) 0.20 (0.25, -0.14-0.50) Pearson R (p value, CI) -0.30 (0.38, -0.79-0.40) R squared 0.04 R squared 0.09
Citation Format: Leeseul Kim, Youjin Oh, Jewel Park, Ilene Hong, Lena Chae, Pedro Viveiros. Real-world concordance between tumor mutation burden from blood and tissue [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2313.