Table 2. Concordance between ctDNA/radiologic and pathological response to neoadjuvant therapy in NSCLC.

	CT			Relative delta mean VAF
	ORR	SD/PD		Responder	Non-responder
MPR	8	1		6	0
Non-MPR	9	4		1	5
Sensitivity	88.89% (51.75–99.72%)			100% (54.07–100.00%)
Specificity	30.77% (9.09–61.43%)			83.33% (35.88–99.58%)
Accuracy	54.55% (32.21–75.61%)			91.67% (61.52–99.79%)
PPV	47.06% (36.64–57.74%)			85.71% (50.06–97.29%)
NPV	80.00% (34.67–96.79%)			100% (NA)
P value	0.360			0.015

A 2-sided Fisher’s exact test was conducted to analyze the association of pathologic response with ctDNA change and radiologic response. Tumor regression was assessed by CT imaging per RECIST v1.1. To aim for a maximum sum of specificity and sensitivity, the threshold for defining responders was determined to −0.98. ctDNA, circulating tumor DNA; NSCLC, non-small cell lung cancer; CT, computed tomography; VAF, variant allele frequency; ORR, objective response rate; SD, stable disease; PD, progressive disease; MPR, major pathologic response, defined as showing no more than 10% residual viable tumor cells; PPV, positive predictive value; NPV, negative predictive value; NA, not available.