- Postsurgical circulating tumor DNA (ctDNA) detected recurrence before computed tomographic (CT) scans and serum carcinoembryonic antigen (CEA) tests in patients with nonmetastatic colorectal cancer (CRC).
Why this matters
- Existing detection methods fall short: CEA lacks sensitivity and specificity, and CT can return nonspecific findings and leads to radiation exposure.
- Findings suggest that ctDNA analysis could complement conventional surveillance strategies to stratify recurrence risk.
- Prospective study of 58 patients with stage I, II, or III CRC who underwent radical surgical resection; blood sample obtained at 1 month postsurgery and every 3-6 months thereafter (n=319).
- Funding: Various nonindustry sources.
- 40 patients received no adjuvant chemotherapy; all 8 with recurrence had a positive ctDNA result.
- 45 patients were ctDNA negative throughout follow-up, and none had a recurrence (0%). Of 13 ctDNA-positive patients, 10 had a recurrence (77%). ctDNA positivity occurred a median of 4 (range, 2-31) months before CT detection.
- Of 32 patients with no recurrence, 29 (91%) had negative ctDNA throughout a median follow-up of 49 months. The 3 ctDNA false-positive cases had stage II/III disease, and later tests returned to normal ctDNA levels.
- CEA was positive in 5 of 8 patients with a recurrence (63%).
- Small study.