Table 1.

Trends in ctDNA literature by cancer type

Cancer types	1989–1999	2000–2004	2005–2009	2010–2014	2015–
NSCLC	1 [104]		6 [39, 40, 105–108]	22 [49, 50, 56, 76, 79, 82, 84, 89, 90, 109–121]	21 [10, 14, 16, 47, 52, 57, 64, 8 3, 85, 122–133]
SCLC					1 [134]
Lung cancer			1 [78]		1 [135]
CRC		1 [77]	2 [41, 136]	12 [48, 98, 137–146]	9 [15, 62, 87, 147–152]
Colon cancer					1 [73]
Breast cancer				4 [66, 69, 153, 154]	7 [8, 61, 67, 99, 155–157]
Ovarian cancer			1 [158]	1 [159]	2 [160, 161]
HCC				2 [34, 162]	2 [163, 164]
Brain tumor					1 [165]
Pancreatic adenocarcinoma	2 [27, 166]				1
Bladder cancer					1 [167]
Prostate cancer				1 [35]	2 [53, 168]
Renal cell carcinoma				1 [1]
Melanoma				1 [169]	5 [88, 170–173]
Lymphoma					1 [174]
Nasopharyngeal carcinoma		1 [175]		1 [176]
Various type	1 [26]	1 [32]	2 [177, 178]	4 [36, 42, 71, 179]	9 [21, 22, 97, 180–185]

Note: The number of publications followed by the references in the bracket are shown in the table.