Postoperative circulating tumor DNA detection is associated with the risk of recurrence in patients resected for a stage II colorectal cancer

Early Dynamics of Circulating Tumor DNA Following Curative Hypofractionated Radiotherapy Related to Disease Control in Lung Cancer

Background/objectives: We aimed to characterize the dynamic pattern of circulating tumor DNA (ctDNA) during hypofractionated radiation therapy (RT) in patients with lung cancer and assess its clinical relevance. Metholds: Prospectively, 24 patients diagnosed with early-stage lung cancer underwent curative RT with 60-64 Gy in 4-20 fractions. Blood samples were collected at baseline (D0) and on post-RT days 1-3 and 7 (D1-3 and D7). The ctDNA was longitudinally analyzed using LiquidSCAN. To find a feasible index associated with outcome, total VAF(%), max VAF(%), total GE (hGE/mL) and max GE (hGE/mL), were evaluated. Results: Thirteen patients with available samples were analyzed with a median 22.2-month follow-up (range, 5.2-34.3 months). Four patients experienced progression between 7.9 and 16.6 months after RT (PD group), and the nine presented no evidence of disease (NED group). The Dmax, the day with the highest ctDNA level among D0-7, was significantly different between the groups with total GE and max GE (p = 0.035 and 0.021, respectively). According to the ROC curves, the max GE showed the best AUC (86.1%) and the cut-off value of the Dmax was 1.5 (sensitivity: 66.7%, specificity: 100%, positive-predictive value: 100%, and negative-predictive value: 57.1%). Tumor size ≥ 3 cm, squamous histology, and a daily dose 3-4 Gy were correlated with the Dmax = D2-3. The Dmax showed better disease control rate with marginal significance (p = 0.081). Conclusions: The timing of early ctDNA elevation may have the potential to predict RT response. The max GE may be an index to verify the ctDNA levels after RT.

Circulating tumor DNA: A new tool to predict recurrence and guide treatment of colorectal cancer

Circulating tumor DNA (ctDNA) has emerged as a promising biomarker with diverse applications across different stages of colorectal cancer management. One of its primary roles is as a prognostic biomarker for detecting post-surgical molecular residual disease and predicting recurrence risk. Compared to traditional biomarkers and tissue biopsies, ctDNA provides a minimally invasive, dynamic, and comprehensive representation of tumor burden and molecular heterogeneity. However, challenges persist in standardizing ctDNA testing, improving sensitivity for early-stage disease, and ensuring widespread accessibility. In this review, we explore the biological characteristics of ctDNA, the methodologies for its detection, and its broad clinical applications in both localized and metastatic colorectal cancer.

Utility of circulating tumor DNA to detect minimal residual disease in colorectal cancer: A systematic review and network meta-analysis

Circulating tumor DNA (ctDNA) is a promising biomarker for predicting minimal residual disease (MRD) and guiding treatment decisions in patients with colorectal cancer (CRC). This study aimed to examine the study designs and settings of ongoing clinical trials that use ctDNA to guide treatment decisions and to determine the best timing for detecting MRD in non-metastatic CRC. We searched PubMed, Embase, Web of Science, Cochrane Library, and clinicaltrials.gov for English language records. The ctDNA settings from the clinical trials were categorized by randomization to ctDNA testing, treatment options based on ctDNA results, and the timing of ctDNA testing relative to adjuvant therapy. For prospective studies, a network meta-analysis using a frequentist approach was conducted to examine the pairwise associations between different ctDNA timing strategies and MRD, defined as recurrence, relapse, and progression. The main approaches in ctDNA-based interventional trial designs were categorized as ctDNA-guided treatment, ctDNA-by-treatment, ctDNA-guided surveillance, and ctDNA-enriched adjuvant therapy for guiding treatment decisions, including both escalation and de-escalation strategies, and surveillance. Overall, both preoperative and postoperative ctDNA detection were linked to higher risks of progression, with pooled hazard ratios (95% confidence intervals) of 5.23 (2.10-13.00) and 7.95 (5.30-11.91), respectively. Among the timing strategies, ctDNA testing after adjuvant therapy was the most effective for identifying high-risk patients, strongly suggesting the presence of residual disease. This study comprehensively reviewed the clinical settings of ctDNA testing in ongoing trials and provided evidence supporting the selection of post-adjuvant therapy as the optimal timing for ctDNA testing.

Circulating tumor DNA as a biomarker of prognosis prediction in colorectal cancer: a systematic review and meta-analysis

OBJECTIVE

Circulating tumor DNA (ctDNA) is increasingly being used as a potential biomarker in colorectal cancer (CRC) patients. However, the role of ctDNA in CRC prognosis prediction remains unclear. The objective is to systematically assess the clinical value of ctDNA in colorectal cancer prognosis prediction throughout the treatment cycle.

METHODS

PubMed, Web of Science, Embase, Cochrane Library, Scopus, and clinical trials.gov database was searched from January 2016 to April 2023. Observational studies and randomized clinical trials reporting on ctDNA and prognostic outcomes in CRC patients were included. Pooled hazard risk ratios (HRs) were calculated for the primary outcomes, relapse-free survival (RFS), and overall survival (OS). Random-effects models were preferred considering the potential heterogeneity.

RESULTS

Sixty-five cohort studies were included. Association between ctDNA and shorter RFS or OS was significant, especially after the full-course treatment recommended by the guidelines (HR = 8.92 [ 95 % CI: 6.02-13.22], P < 0.001, I2 = 73 %; HR = 3.05 [ 95 % CI: 1.72-5.41], P < 0.001, I2 = 48 %) for all types of CRC patients. Despite the presence of heterogeneity, subgroup analyses showed that the cancer type and ctDNA detection assays may be the underlying cause. Besides, ctDNA may detect recurrence earlier than radiographic progression, but no uniform sampling time point between studies might bring bias. However, ctDNA detection did not appear to correlate with pathological complete response achievement in patients with locally advanced rectal cancer.

CONCLUSION

ctDNA detection was significantly associated with poorer prognosis. The potential applications in prognostic prediction are promising and remain to be evaluated in other fields.

Circulating tumor DNA to monitor treatment response in solid tumors and advance precision oncology

Circulating tumor DNA (ctDNA) has emerged as a dynamic biomarker in cancer, as evidenced by its increasing integration into clinical practice. Carrying tumor specific characteristics, ctDNA can be used to inform treatment selection, monitor response, and identify drug resistance. In this review, we provide a comprehensive, up-to-date summary of ctDNA in monitoring treatment response with a focus on lung, colorectal, and breast cancers, and discuss current challenges and future directions.

Circulating Tumor DNA as a Real-Time Biomarker for Minimal Residual Disease and Recurrence Prediction in Stage II Colorectal Cancer: A Systematic Review and Meta-Analysis

The role of adjuvant chemotherapy (adj-CT) in stage II colon cancer remains controversial. Circulating tumor DNA (ctDNA) is a promising biomarker for detecting minimal residual disease (MRD) and predicting recurrence. This systematic review and meta-analysis evaluated the prognostic value of ctDNA in stage II colorectal cancer (CRC), focusing on postoperative detection, post adj-CT outcomes, and dynamic surveillance. A literature search identified studies correlating ctDNA positivity in stage II CRC with recurrence risk, recurrence-free survival (RFS), and disease-free survival (DFS). Seven studies met the inclusion criteria. Postoperative ctDNA positivity significantly increased the risk of recurrence (pooled risk ratio [RR:] 3.66; 95% confidence interval [CI]: 1.25-10.72; p = 0.002). CtDNA positivity after adj-CT was strongly associated with poor survival, while dynamic ctDNA monitoring detected recurrence earlier than conventional methods, including carcinoembryonic antigen (CEA) and imaging. CtDNA is a robust prognostic biomarker in stage II CRC, enabling personalized treatment. High-risk ctDNA-positive patients may benefit from intensified therapy, while ctDNA-negative patients could avoid unnecessary treatments. However, the standardization of detection methods and large-scale validation studies are needed before integrating ctDNA into routine clinical practice as a non-invasive, dynamic tool for personalized care.