Ali Alqahtani, MD1, Sami Ghazaleh, MD2, Rakan Albalawy, MD, MS2, Waleed Abdulsattar, MD2, Michael Cook, MD3, Wade Lee-Smith4, Muhammad Aziz, MD2, Mohammed Najeeb Alhallak, MD, MS5; 1Georgetown University, Arlington, VA; 2University of Toledo Medical Center, Toledo, OH; 3Georgetown University, Washington, DC; 4University of Toledo, Toledo, OH; 5Karmanos Cancer Institute, Wayne State University, Detroit, MI
Introduction: Approximately 20% of stage II and 40% of stage III colon cancer patients experience recurrence of the disease despite primary therapies with curative intent. Circulating tumor DNA (ctDNA) is a novel method to detect residual disease in postoperative colon cancer patients. The purpose of our meta-analysis is to investigate the utility of postoperative ctDNA as a prognostic tool of relapse free survival in stage II/III colon cancer patients following curative intent surgery. Methods: We performed a comprehensive search in the literature for studies that evaluated postoperative ctDNA measurement in stage II and III colon cancer. We searched the databases of PubMed/MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and Web of Science Core Collection from databases inception until May 28, 2020. The search was not limited by language, study design, or country of origin. Two researchers (AA and SG) independently selected the studies; discrepancies were resolved by a third researcher (MA). We considered randomized controlled trials, cohort studies, case-control studies, and case series. We excluded animal studies, case reports, review articles, editorials, and letters to editor. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The random-effects model was used to calculate the Relapse Free Survival (RFS) Hazard Ratio (HR) and its 95% confidence interval (CI). Publication bias was assessed visually by generating a funnel plot of the studies . We also performed Egger’s regression to quantitively assess publication bias, where p < 0.05 was considered statistically significant for publication bias. Results: We included five studies with a total of 731 patients. A significantly worse relapse free survival was noted in patients with positive ctDNA compared to negative ctDNA (HR, 9.864; 95% CI, 6.345-15.334 P < .001). There was a visible symmetry in the funnel plot of the studies that reported positive ctDNA postoperatively, suggesting no publication bias. Similarly, Egger’s test was not statistically significant implying no publication bias (p = 0.75)
Discussion: In conclusion, our meta-analysis shows that postoperative ctDNA is a useful prognostic marker for RFS in patients with stage II/III colon cancer following surgery with curative intent. However, further prospective clinical trials are needed to validate the utility of ctDNA as a prognostic tool.
Disclosures: Ali Alqahtani indicated no relevant financial relationships. Sami Ghazaleh indicated no relevant financial relationships. Rakan Albalawy indicated no relevant financial relationships. Waleed Abdulsattar indicated no relevant financial relationships. Michael Cook indicated no relevant financial relationships. Wade Lee-Smith indicated no relevant financial relationships. Muhammad Aziz indicated no relevant financial relationships. Mohammed Najeeb Alhallak indicated no relevant financial relationships.