Table 1 Detection of ctDNA in plasma samples obtained from patients just before surgery to remove primary tumour (“pre-op”) and within five days after surgery (“post-op”).

From: Individualised multiplexed circulating tumour DNA assays for monitoring of tumour presence in patients after colorectal cancer surgery

Patient ctDNA fraction Days after surgery
Pre-op Post-op
Early stage cancer, curative-intent surgery
 130 0.0022 ND 3
 206 0.0006 ND 4
 405 0.0047 ND 4
 410 0.0011
 417 ND ND 5
 440 0.0107 ND 4
 441 ND ND 4
 442 0.0019
 478 0.0050 ND 3
 480 0.0015 ND 4
 486 0.0065 ND 4
 495 0.0038 ND 4
Metastatic cancer, palliative resection
 494 0.0135 0.021 3
  1. ‘ND’ refers to ‘not detected’ and a dash means no plasma sample was available.