Abstract 509P
Background
Circulating tumor DNA (ctDNA) is a novel biomarker to monitor treatment response and predict cancer recurrence or progression. However, the real-world utilization and performance of ctDNA monitoring is not well-characterized, particularly in underrepresented patient populations like the Southeast Asians.
Methods
This retrospective multi-center analysis included patients who had stage I-IV lung, colorectal, breast, gastric, liver or ovarian cancer and had at least one commercial ctDNA test (K-TrackTM, Gene Solutions) between August 2022 and December 2023. A personalized tumor-informed ctDNA assay was performed for 623 patients and 815 plasma samples to quantify ctDNA before and after treatment. Clinical data of minimum 6 months after the last ctDNA test was available for 263 early-stage patients to analyze the prognostic value of ctDNA to predict recurrence.
Results
ctDNA was tested for only 1 time after treatment in 61.2% of the patients, and for those who had at least 2 tests, it was mainly repeated every 3-6 months. In the early-stage I-III, pre-operative ctDNA detection rates were 66.7%, 84.6%, 54.3%, 52.6%, 93.3%, 75.0% for lung, colorectal, breast, gastric, liver or ovarian cancer respectively. After surgery, 84.4% (38/45) of patients with recurrence had ctDNA detected in the plasma while 96.3% (210/218) of patients with no recurrence had negative results. ctDNA positivity significantly increased the risk of recurrence in lung (HR = 71.3; 95% CI: 17.6 – 287.8), colorectal (HR = 44.3; 95% CI: 11.3 – 173.2), breast (HR = 37.6, 95% CI: 3.09 – 456.8), and gastric (HR = >100, 95% CI: 26.9 – >100.0) cancer. In the metastatic stage IV, pre-treatment ctDNA detection rates were 80.0%, 87.7%, 73.3%, 70.6%, 91.7%, 81.8% for lung, colorectal, breast, gastric, liver or ovarian cancer respectively. Case studies were presented to demonstrate real-world utilization of ctDNA monitoring during all phases of cancer management.
Conclusions
This first analysis of real-world data indicated that ctDNA was an independent and strong prognostic biomarker to predict recurrence and progression in multiple types of cancer. This assay could be helpful for clinical decision making by enabling personalized intervention and surveillance.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Gene Solutions JSC.
Disclosure
All authors have declared no conflicts of interest.