Abstract 589P
Background
Circulating tumor DNA (ctDNA) based molecular residual disease (MRD) detection has been shown to predict prognosis and guide individualized management of colorectal cancer (CRC). The landmark point is usually set at 4-12 weeks post resection in consideration of the disturbance to cell-free DNA (cfDNA) by surgery. This study aimed to evaluate the feasibility of moving the landmark point to 1-week post resection.
Methods
The study prospectively and consecutively enrolled stage I-IV CRC patients who received R0 resection. Blood samples at baseline, post-operative day (POD) 7, POD30 and subsequent every 3-6 months surveillance were collected. The MRD status of all the samples were evaluated by the Burning Rock Patient-specific pROgnostic and Potential tHErapeutic marker Tracking (brPROPHETTM) approach. The cfDNA level, mean tumor mutant (MTM), positive predictive value (PPV) and negative predictive value (NPV) were compared between POD7 and POD30.
Results
In total, 164 eligible patients were enrolled. The median follow-up duration was 311 days (95% CI, 296-351) up to date. The brPROPHET displayed a high sensitivity of 95.1% (155/163) for detecting ctDNA preoperatively, with 88.5%, 96.1%, 96.2%, 100% in stage I to IV, respectively. Post-resection ctDNA positive rates were decreased to 15.2% (25/164) at POD7 and 12.8% (21/164) at POD30. The cfDNA levels of POD7 were significantly higher than those of baseline and POD30 (P<0.001). However, the MTMs were similar between POD7 and POD30 (P = 0.55). The accordance between POD7 and POD30 was 91.5% (150/164). For 6-month recurrence, the PPV was 13.6% vs 15.8% for POD7 and POD30, respectively, with NPV of 100% vs 98.2%. Of the 25 ctDNA positive patients at POD7, 9 turned negative at POD30 and had significantly lower ctDNA levels at POD7 than those who didn’t (P<0.001). Patients with decreased ctDNA from POD7 to POD30 had a higher ctDNA clearance rate during surveillance than those without decreased ctDNA (100% vs 30%, P = 0.02).
Conclusions
The performance of ctDNA detection in POD7 and POD30 was similar. Shift of the landmark time to 1-week post resection may provide an easier way to evaluate MRD status for prognostic stratification.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
548P - Diffuse midline gliomas H3K27-altered in adults, the experience of an oncology center
Presenter: Carolina Trabulo
Session: Poster session 10
561P - Risk of colorectal cancer and premalignant lesions after kidney transplantation
Presenter: Koen Zwart
Session: Poster session 10
562P - Quantifying the effect of colonoscopy and polypectomy rates in stage shift of colorectal cancer and reduced need for adjuvant chemotherapy
Presenter: Mina Sarofim
Session: Poster session 10
563P - The impact of participation in colorectal cancer screening: A population-based results from Lithuania
Presenter: Tomas Poskus
Session: Poster session 10
564P - A large-scale real-world study for colorectal cancer screening
Presenter: Song LIU
Session: Poster session 10
565P - Real-world data of early-onset colon cancer (early-onset CC) from the AIO colopredict plus (CPP) registry: Clinical and molecular characteristics, treatment and outcome
Presenter: Doreen Gisder
Session: Poster session 10
566P - Long-term survivorship outcomes of adolescents and young adults (AYA) with cancer of the lower gastrointestinal tract
Presenter: Winette Van Der Graaf
Session: Poster session 10
567P - Impact of concomitant medication on recurrence, survival and tolerability of chemotherapy in early colon cancer patients: Results from the PETACC 8 study
Presenter: Elisabeth Bergen
Session: Poster session 10
568P - Single cell AI-based detection of DNA mismatch repair deficiency in 1,988 colorectal cancers reveals prognostic and predictive value in the SCOT trial
Presenter: Faiz Jabbar
Session: Poster session 10
569P - Artificial intelligence for detection of mismatch repair deficiency in colon carcinomas (alliance)
Presenter: Frank Sinicrope
Session: Poster session 10