Unraveling the potential clinical utility of circulating tumor DNA detection in colorectal cancer-evaluation in a nationwide Danish cohort

The role of circulating tumor DNA (ctDNA) in urothelial cancers

The role of circulating tumor DNA (ctDNA) in urothelial cancers is a rapidly evolving area of research. Urothelial cancer is the most common subtype of bladder cancer, and biomarkers that predict response or prognosticate outcomes have been long sought after. Tumor-informed ctDNA assays have been utilized in several other cancers and increasingly used in both muscle invasive bladder cancer (MIBC) and metastatic urothelial cancer (mUC) to inform treatment decision-making. While a universal consensus on ctDNA testing has not been fully defined and discussed herein, understanding its benefits and limitations is important to help guide the practical application in the clinic.

Towards Recommendations for Cost-Effectiveness Analysis of Predictive, Prognostic, and Serial Biomarker Tests in Oncology

BACKGROUND

Cost-effectiveness analysis (CEA) of biomarkers is challenging due to the indirect impact on health outcomes and the lack of sufficient fit-for-purpose data. Hands-on guidance is lacking.

OBJECTIVE

We aimed firstly to explore how CEAs in the context of three different types of biomarker applications have addressed these challenges, and secondly to develop recommendations for future CEAs.

METHODS

A scoping review was performed for three biomarker applications: predictive, prognostic, and serial testing, in advanced non-small cell lung cancer, early-stage colorectal cancer, and all-stage colorectal cancer, respectively. Information was extracted on the model assumptions and uncertainty, and the reported outcomes. An in-depth analysis of the literature was performed describing the impact of model assumptions in the included studies.

RESULTS

A total of 43 CEAs were included (31 predictive, 6 prognostic, and 6 serial testing). Of these, 40 utilized different sources for test and treatment parameters, and three studies utilized a single source. Test performance was included in 78% of these studies utilizing different sources, but this parameter was differently expressed across biomarker applications. Sensitivity analyses for test performance was only performed in half of these studies. For the linkage of test results to treatments outcomes, a minority of the studies explored the impact of suboptimal adherence to test results, and/or explored potential differences in treatment effects for different biomarker subgroups. Intermediate outcomes were reported by 67% of studies.

CONCLUSIONS

We identified various approaches for dealing with challenges in CEAs of biomarker tests for three different biomarker applications. Recommendations on assumptions, handling uncertainty, and reported outcomes were drafted to enhance modeling practices for future biomarker cost-effectiveness evaluations.

Timing of ctDNA Analysis Aimed at Guiding Adjuvant Treatment in Colorectal Cancer

PURPOSE

Multiple clinical trials are investigating ctDNA to guide adjuvant chemotherapy (ACT) in colorectal cancer. Timely ACT initiation necessitates early ctDNA testing, but the impact of postoperative cell-free DNA (cfDNA) and ctDNA dynamics remains unclear, particularly with cost-reducing input caps employed in some assays. This study investigates ctDNA detection at day 14 versus day 30, comparing whole-sample analysis with capping the cfDNA input, and evaluates single and dual timepoint assessments for ACT allocation.

EXPERIMENTAL DESIGN

From 2019 to 2023, 611 patients with stage I to III colorectal cancer were enrolled. Blood was collected preoperatively and postoperatively on ∼day 14 and ∼day 30. The cfDNA levels were assessed using digital PCR, and ctDNA was assessed using tumor-informed digital PCR or targeted sequencing analyzing all cfDNA from 8 mL of plasma.

RESULTS

Despite elevated cfDNA in 85% of day 14 samples, performance was comparable between the two timepoints (sensitivity, 31% vs. 32% and specificity, both 98%). A 50-ng cfDNA input cap reduced ctDNA detection probability, affecting 78% of day 14 samples and 65% of day 30 samples. At both timepoints, ctDNA detection was prognostic of recurrence (day 14; HR, 9.0, 95% confidence interval, 5.5-14.8 and day 30: HR, 12.5, 95% confidence interval, 7.6-20.4). In 74% of ctDNA-positive recurrence patients, both samples had ctDNA detected. An increase in the ctDNA level from day 14 to day 30 was associated with a shorter time to recurrence (Pearson R = -0.63, P = 0.003). Combining the timepoints would increase sensitivity (36%) and allow earlier ACT start in 80% of patients.

CONCLUSIONS

Early ctDNA sampling is feasible and highly prognostic. Supplemental later testing may improve sensitivity while allowing early ACT initiation for most ctDNA-positive patients.

Whole-exome tumor-agnostic ctDNA analysis enhances minimal residual disease detection and reveals relapse mechanisms in localized colon cancer

In stage 2-3 colon cancer (CC), postsurgery circulating tumor DNA (ctDNA) assessment is crucial for guiding adjuvant chemotherapy (ACT) decisions. While existing assays detect ctDNA and help identify high-risk persons with CC for recurrence, their limited sensitivity after surgery poses challenges in deciding on ACT. Additionally, a substantial portion of persons with CC fail to clear ctDNA after ACT, leading to recurrence. In this study, we performed whole-exome sequencing (WES) of ctDNA at different time points in participants with relapsed CC in two independent cohorts, alongside transcriptomic and proteomic analyses of metastases, to enhance comprehension of progression mechanisms. A plasma WES-based tumor-agnostic assay demonstrated higher sensitivity in detecting minimal residual disease (MRD) compared to current assays. Immune evasion appears to be the primary driver of progression in the localized CC setting, indicating the potential efficacy of immunotherapy for microsatellite stability in persons with CC. Organoid modeling further supports the promising potential of targeted therapy in eradicating MRD, surpassing conventional treatments.

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.

Liquid Biopsy in Peritoneal Carcinomatosis from Colorectal Cancer: Current Evidence and Future Perspectives

Peritoneal carcinomatosis (PC) represents a challenge in the management of metastatic colorectal cancer (mCRC) because of the difficulties in diagnosis, tumor burden assessment, and in selecting the optimal treatments. A critical limitation is the lack of robust prognostic and predictive biomarkers, largely relying on serum markers (e.g., carcinoembryonic antigen) or the peritoneal carcinomatosis index (PCI) for disease extent. Circulating tumor DNA (ctDNA)-genomic fragments shed by tumor cells into the bloodstream-is now recommended by international guidelines for mCRC management. Its potential extends to PC, where it may enhance diagnostic, therapeutic, and follow-up strategies. However, PC from CRC (PC-CRC) is associated with lower ctDNA levels and detection rates compared to other metastatic sites, posing a challenge for its clinical utility. To address these limitations, peritoneal fluid analysis has emerged as a promising alternative, with peritoneal tumor DNA (ptDNA) detected at higher concentrations in this anatomical space. Integrating ctDNA and ptDNA may offer a deeper understanding of PC-CRC biology and provide more precise tools for managing this complex disease. This approach has the potential to revolutionize the treatment paradigm for PC-CRC, bringing precision medicine even to this subgroup of patients traditionally associated with poor outcomes. This review aims to evaluate the diagnostic, prognostic, and therapeutic implications of ctDNA and ptDNA in PC-CRC, highlighting current limitations and future directions.

Prognostic significance of circulating tumor DNA detection and quantification in cervical cancer: a systematic review and meta-analysis

Background

Circulating tumor DNA (ctDNA) is an emerging biomarker in cervical cancer, with elevated levels typically indicating a higher tumor burden. However, its prognostic value in cervical cancer patients remains debated. This meta-analysis aims to clarify the prognostic significance of ctDNA in this patient population.

Methods

We searched the PubMed, Cochrane Library, CNKI, and EMBASE databases for studies published up to September 30, 2024, to investigate the prognostic significance of ctDNA in cervical cancer patients. The outcome measures included overall survival (OS) and progression-free survival (PFS)/disease-free survival (DFS).

Results

This analysis included 10 studies encompassing a total of 706 cervical cancer patients. Findings revealed that patients with detectable baseline ctDNA had significantly poorer OS(HR = 1.64, 95% CI = 1.45-1.86, P < 0.001) as well as worse PFS or DFS (HR = 1.42, 95% CI = 1.07-1.89, P = 0.015). Additionally, ctDNA detectability during treatment was strongly associated with poorer OS (HR = 17.22, 95% CI = 4.43-66.89, P < 0.001) and PFS/DFS (HR = 4.16, 95% CI = 2.57-6.73, P < 0.001).

Conclusions

This meta-analysis demonstrates that elevated ctDNA levels are significantly associated with poorer PFS, DFS, and OS in patients with cervical cancer. However, data regarding the association between ctDNA levels and OS are relatively limited, and the number of included studies remains small, with a potential risk of publication bias. Based on the current evidence, ctDNA shows promise as a valuable tool for pre-treatment assessment and an effective biomarker for monitoring therapeutic response and disease progression. Further large-scale, prospective studies are warranted to validate these findings and establish their reliability and clinical applicability.

Systematic Review Registration

inplasy.com, identifier INPLASY2024120083.

Japan society of clinical oncology position paper on appropriate clinical use of molecular residual disease (MRD) testing

Although the 5-year relative survival rates for resectable solid tumors have improved over the past few years, the risk of postoperative recurrence necessitates effective monitoring strategies. Recent advancements in molecular residual disease (MRD) testing based on circulating tumor DNA (ctDNA) analysis have shown considerable promise in the context of predicting recurrence; however, significant barriers to widespread clinical implementation remain-mainly, low awareness among healthcare professionals, high costs, and lack of standardized assays and comprehensive evidence. This position paper, led by the Japan Society of Clinical Oncology, aims to establish a common framework for the appropriate clinical use of MRD testing in a tumor type-agnostic manner. It synthesizes currently available evidence, reviews region-specific clinical trends, addresses critical clinical questions related to MRD testing, and offers recommendations to guide healthcare professionals, biotechnology and pharmaceutical companies, and regulatory authorities. These recommendations were developed based on a voting process involving 15 expert members, ensuring a consensus-driven approach. These findings underscore the importance of collaborative efforts among various stakeholders in enhancing the clinical utility of MRD testing. This project aimed to foster consensus and provide clear guidelines to support the advancement of precision medicine in oncology and improve patient outcomes in the context of perioperative care.

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.

Minimal residual disease in colorectal cancer. Tumor-informed versus tumor-agnostic approaches: unraveling the optimal strategy

BACKGROUND

Circulating tumor DNA (ctDNA) analysis has emerged as a minimally invasive tool for detecting minimal residual disease (MRD) in colorectal cancer (CRC) patients. This enables dynamic risk stratification, earlier recurrence detection and optimized post-surgical treatment. Two primary methodologies have been developed for ctDNA-based MRD detection: tumor-informed strategies, which identify tumor-specific mutations through initial tissue sequencing to guide ctDNA monitoring, and tumor-agnostic approaches, which utilize predefined panels to detect common cancer-associated genomic or epigenomic alterations directly from plasma without prior tissue analysis. The debate over which is superior in terms of sensitivity, specificity, cost-effectiveness and clinical feasibility remains unsolved.

DESIGN

This review summarizes studies published up to November 2024, exploring the utility and performance of tumor-informed and tumor-agnostic approaches for ctDNA analysis in CRC. We evaluate the strengths and limitations of each methodology, focusing on sensitivity, specificity and clinical outcomes.

RESULTS

Both strategies demonstrate clinical utility in post-operative risk stratification and guiding adjuvant chemotherapy decisions in CRC patients. Tumor-informed approaches generally exhibit superior sensitivity and specificity for recurrence prediction, attributed to their personalized tumor profile designs. However, these methods are limited by the need for prior tissue sequencing and higher associated costs. In contrast, tumor-agnostic approaches offer broader applicability due to their reliance on plasma-only analysis, although with relatively lower sensitivity. Technological advancements, including fragmentomics and multi-omic integrations, are expanding the capabilities of ctDNA-based MRD detection, enhancing the performance of both approaches.

CONCLUSIONS

While tumor-informed strategies currently offer higher precision in MRD detection, tumor-agnostic approaches are gaining traction due to their convenience and improving performance metrics. The integration of novel technologies in ongoing clinical trials may redefine the optimal approach for MRD detection in CRC, paving the way for more personalized and adaptive patient management strategies.

Proposal of real-world solutions for the implementation of predictive biomarker testing in patients with operable non-small cell lung cancer

The implementation of biomarker testing for targeted therapies and immune checkpoint inhibitors is a cornerstone in the management of metastatic and locally advanced non-small cell lung cancer (NSCLC), playing a pivotal role in guiding treatment decisions and patient care. The emergence of precision medicine in the realm of operable NSCLC has been marked by the recent approvals of osimertinib, atezolizumab, nivolumab, pembrolizumab and alectinib for early-stage disease, signifying a shift towards more tailored therapeutic strategies. Concurrently, the landscape of this disease is rapidly evolving, with several further pending approvals and numerous clinical trials in progress. To harness the benefits of these innovative neo-adjuvant and adjuvant therapies, the integration of predictive biomarker testing into standard clinical protocols is imperative for patients with operable NSCLC. A multidisciplinary international consortium has identified three primary obstacles impeding the effective testing of patients with operable NSCLC. These challenges encompass the limited number of test requests by physicians, the inadequacy of tissue samples for comprehensive testing, and the prevalence of cost-reduction measures leading to suboptimal testing practices. This review delineates the aforementioned challenges and proposed solutions, and strategic recommendations aimed at enhancing the testing process. By addressing these issues, we strive to optimize patient outcomes in operable NSCLC, ensuring that individuals receive the most appropriate and effective care based on their unique disease profile.

The role of renal and liver function in clinical ctDNA testing

Circulating tumor DNA (ctDNA) has high clinical potential in early cancer detection. The renal system and the liver are involved in clearing circulating cell free DNA (cfDNA) from the blood. Recent studies on mice show that inhibiting the liver's ability to clear cfDNA results in elevated ctDNA levels in blood samples. Emphasizing the need for studies in humans exploring if markers of renal and liver function are associated with cfDNA and ctDNA levels in the blood. The present study investigates if cfDNA level, ctDNA level and ctDNA detection is affected in colorectal cancer (CRC) patients with clinical biomarkers indicative of low renal and liver function. We requisitioned standard laboratory tests of renal and liver function, measured within thirty days of curative intended surgery from 846 stage I-III CRC patients. For each patient, matching preoperative cfDNA and ctDNA data was available. We investigated the correlation between impaired renal and liver function and cfDNA level, ctDNA level, and ctDNA detection. The findings revealed that variation in renal and liver function in stage I-III CRC patients did not affect cfDNA level, ctDNA level, or ctDNA detection and that ctDNA test results remain stable over a wide range of renal and liver biomarker results.

A scoping review of factors influencing the implementation of liquid biopsy for cancer care

BACKGROUND

Liquid biopsy (LB) offers a promising, minimally invasive alternative to traditional tissue biopsies in cancer care, enabling real-time monitoring and personalized treatment. Despite its potential, the routine implementation of LB in clinical practice faces significant challenges. This scoping review examines the barriers and facilitators influencing the implementation of liquid biopsies into standard cancer care.

METHODS

Four academic databases (PubMed, Scopus, Embase, and Web of Science) were systematically searched without language restrictions. We included peer-reviewed articles that were published between January 2019 and March 2024 that focused on the implementation of LB in cancer care or described barriers and facilitators to its implementation. Data relevant to the review objective, including key article characteristics; barriers and facilitators of implementation; and recommendations for advancement or optimisation; were extracted and analysed using thematic and visual network analyses.

RESULTS

The majority of the included articles were narrative review articles (84%), with most from China (24.2%) and the United States (20%). Thematic analysis identified four main categories and their associated barriers and facilitators to the implementation of LB in cancer care: (1) Laboratory and personnel requirements; (2) Disease specificity; (3) Biomarker-based liquid biopsy; and (4) Policy and regulation. The majority of barriers identified were concentrated in the pre-analytical phase, highlighting the lack of standardization in LB technologies and outcomes.

CONCLUSIONS

Through a thematic analysis of the barriers and facilitators to LB implementation, we present an integrated tool designed to encourage the standardization of testing methods for clinical practice guidelines in the field.

Advances in liquid biopsy: From exploration to practical application

Liquid biopsy has received tremendous attention as a non-invasive approach for detecting and tracking cancer. Here, we discuss the latest work on circulating tumor DNA and circulating tumor cells with respect to clinical applications, including cancer screening, early detection of relapse, real-time monitoring of therapeutic efficacy, and detection of therapeutic targets and resistance mechanisms.

The prognostic value of circulating tumor DNA in malignant melanoma patients treated with immune checkpoint inhibitors: a systematic review and meta-analysis

Background

Circulating tumor DNA (ctDNA) is an emerging biomarker in malignant melanoma(MM), and high levels of ctDNA may reflect a higher tumor load. However, its prognostic value for MM receiving immune checkpoint inhibitors(ICI) remains controversial. This meta-analysis aimed to elucidate the prognostic significance of ctDNA in this patient population.

Methods

We conducted a comprehensive search of the PubMed, Cochrane Library, CNKI, and EMBASE databases, including studies published up to August 15, 2024, to investigate the prognostic impact of ctDNA in MM patients treated with ICI. Using a fixed-effects model, we systematically evaluated the association between ctDNA levels and key survival outcomes, including overall survival (OS) and progression-free survival (PFS). Additionally, funnel plots, Begg's test, and Egger's test were employed to assess potential publication bias.

Results

Twelve studies from eleven articles, involving a total of 1063 eligible MM patients receiving ICI therapy, were included. The results indicated that patients with detectable ctDNA before initiating ICI therapy had significantly poorer OS (HR = 3.19, 95% CI = 2.22-4.58, P < 0.001) and PFS (HR = 2.08, 95% CI = 1.61-2.69, P < 0.001). Furthermore, the detectability of ctDNA during treatment was also significantly associated with worse OS (HR = 4.57, 95% CI = 3.03-6.91, P < 0.001) and PFS (HR = 3.79, 95% CI = 2.13-6.75, P < 0.001).

Conclusions

This meta-analysis indicates that in MM patients receiving ICI therapy, detectable and high levels of ctDNA are significantly associated with poorer OS and PFS. Therefore, ctDNA can serve as a diagnostic and stratification tool prior to treatment, as well as an effective indicator for monitoring treatment response and disease progression.

Systematic Review Registration

www.inplasy.com, identifier INPLASY2024110018.

Value of ctDNA in surveillance of adjuvant chemosensitivity and regimen adjustment in stage III colon cancer: a protocol for phase II multicentre randomised controlled trial (REVISE trial)

INTRODUCTION

The standard of care for stage III colon cancer is 3 or 6 months of double-drug regimen chemotherapy following radical surgery. However, patients with positive circulating tumour DNA (ctDNA) exhibit a high risk of recurrence risk even if they receive standard adjuvant chemotherapy. The potential benefit of intensified adjuvant chemotherapy, oxaliplatin, irinotecan, leucovorin and fluoropyrimidine (FOLFOXIRI), for ctDNA-positive patients remains to be elucidated.

METHODS AND ANALYSIS

This multicentre phase II randomised controlled trial aims to investigate the utility of ctDNA in monitoring chemosensitivity and to preliminarily assess whether intensified chemotherapy with FOLFOXIRI can increase ctDNA clearance and improve survival outcomes. A total of 60 eligible patients with stage III colon cancer exhibiting postoperatively positive ctDNA before and after two cycles of oxaliplatin and capecitabine (XELOX) will be randomly assigned to continue five additional cycles of XELOX (control arm) or switch to eight cycles of FOLFOXIRI (experimental arm). This sequential approach is designed to escalate treatment for patients with persistent ctDNA positivity while avoiding overtreatment in those who may respond well to standard chemotherapy. The primary endpoint is the change in ctDNA concentration, defined as the difference between the ctDNA concentration measured after two cycles of XELOX and after the completion or termination of chemotherapy. Secondary endpoints include the ctDNA clearance rate, 2-year disease-free survival, distant metastasis-free survival, chemotherapy-related side effects and quality of life.

ETHICS AND DISSEMINATION

This trial has been approved by the Ethics Committee of the West China Hospital, Sichuan University (approval number: 20231998). The findings will be disseminated through peer-reviewed publications and presentations at scientific conferences.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov (NCT06242418, registered on 27 January 2024).

Minimal residual disease as a target for liquid biopsy in patients with solid tumours

Metastasis is the leading cause of cancer-related death in patients with solid tumours. Current imaging technologies are not sufficiently sensitive to detect minimal residual disease (MRD; also known as measurable or molecular residual disease) after initial surgery or chemotherapy, pointing to the need for more sensitive tests to detect remaining traces of cancer in the body. Liquid biopsy, or the analysis of tumour-derived or tumour-induced cells or cellular products in the blood or other body fluids, has opened a new diagnostic avenue to detect and monitor MRD. Liquid biopsy is already used in clinical decision making for patients with haematological malignancies. Here, we review current knowledge on the use of circulating tumour DNA (ctDNA) to detect and monitor MRD in patients with solid tumours. We also discuss how ctDNA-guided MRD detection and characterization could herald a new era of novel 'post-adjuvant therapies' with the potential to eliminate MRD and cure patients before terminal metastatic disease is evident on imaging.

Application of Circulating Tumor DNA in the Auxiliary Diagnosis and Prognosis Prediction of Glioma

Glioma is the most common primary malignant brain tumor. Despite significant advances in the past decade in understanding the molecular pathogenesis of this tumor and exploring therapeutic strategies, the prognosis of patients with glioma remains poor. Accurate diagnosis of glioma is very important for the treatment and prognosis. Although the gold-standard method for the diagnosis and prognosis prediction of patients with glioma is tissue biopsy, it still has many limitations. Liquid biopsy can provide information on the auxiliary diagnosis and prognosis of gliomas. In this review, we summarized the application of cell-free DNA (cfDNA) and circulating tumor DNA (ctDNA) in the auxiliary diagnosis and prognosis of glioma. The common methods used to detect ctDNA in gliomas using samples including blood and cerebrospinal fluid (CSF) and the detection techniques for ctDNA, including droplet digital PCR (ddPCR) and next-generation sequencing (NGS), were discussed. Detection of ctDNA from plasma of patients with brain tumors remains challenging because of the blood-brain barrier (BBB). CSF has been proposed as a medium for ctDNA analysis in brain tumors, and mutation detection using plasma ctDNA was less sensitive than CSF ctDNA sequencing. Moreover, ongoing relevant clinical studies were summarized. Finally, we discussed the challenges, and future directions for the studies on ctDNA in glioma.

ctDNA in the reading room: A guide for radiologists

Liquid biopsy with sequencing of circulating tumor DNA (ctDNA) is a minimally invasive method for sampling body fluids and offers a promising alternative to tissue biopsies that involve greater risks, costs, and time. ctDNA not only identifies actionable targets by revealing unique molecular signatures in cancer, but also may assess treatment response, treatment resistance and progression, and recurrence. Imaging correlates of these applications are already being identified and utilized for various solid tumors. Radiologists have new challenges in interpreting oncologic imaging. Given their integral role in cancer surveillance, they must become familiar with the importance of ctDNA in detecting recurrence and minimal residual disease, measuring treatment response, predicting survival and metastatic patterns, and identifying new molecular therapeutic targets. In this review, we provide an overview of ctDNA testing, and a snapshot of current clinical guidelines from the National Comprehensive Cancer Network and the European Society of Molecular Oncology on the use of ctDNA in lung, breast, colorectal, pancreatic, and hepatobiliary cancers. For each cancer type, we also highlight current research applications of ctDNA that are relevant to the field of diagnostic radiology.

Stool and blood biomarkers for colorectal cancer management: an update on screening and disease monitoring

BACKGROUND

Biomarkers have revolutionized the management of colorectal cancer (CRC), facilitating early detection, prevention, personalized treatment, and minimal residual disease (MRD) monitoring. This review explores current CRC screening strategies and emerging biomarker applications.

MAIN BODY

We summarize the landscape of non-invasive CRC screening and MRD detection strategies, discuss the limitations of the current approaches, and highlight the promising potential of novel biomarker solutions. The fecal immunochemical test remained the cornerstone of CRC screening, but its sensitivity has been improved by assays that combined its performance with other stool analytes. However, their sensitivity for advanced adenomas and the patient compliance both remain suboptimal. Blood-based tests promise to increase compliance but require further refinement to compete with stool-based biomarker tests. The ideal scenario involves leveraging blood tests to increase screening participation, and simultaneously promote stool- and endoscopy-based screening among those who are compliant. Once solely reliant on upfront surgery followed by stage and pathology-driven adjuvant chemotherapy, the treatment of stage II and III colon cancer has undergone a revolutionary transformation with the advent of MRD testing after surgery. A decade ago, the concept of using a post-surgical test instead of stage and pathology to determine the need for adjuvant chemotherapy was disruptive. Today, a blood test may be more informative of the need for chemotherapy than the stage at diagnosis.

CONCLUSION

Biomarker research is not just improving, but bringing a transformative change to CRC clinical management. Early detection is not just getting better, but improving thanks to a multi-modality approach, and personalized treatment plans are not just becoming a reality, but a promising future with MRD testing.

A novel risk classification model integrating CEA, ctDNA, and pTN stage for stage 3 colon cancer: a post hoc analysis of the IDEA-France trial

BACKGROUND

We assessed the added value of incorporating carcinoembryonic antigen (CEA) to circulating tumor DNA (ctDNA) and pathological TN (pTN) stage for risk classification in stage 3 colon cancer (CC).

PATIENTS AND METHODS

We retrospectively analyzed postoperative CEA values in patients with CC from the IDEA-France phase 3 trial. The relation between disease-free survival (DFS) and CEA was modeled through restricted cubic splines. Prognostic value of CEA, ctDNA, and pTN was assessed with the Kaplan-Meier method. Multivariate analysis was used to identify prognostic and predictive factors for DFS.

RESULTS

Among 696 patients (35%), CEA values were retrievable, and for 405 (20%) both CEA and ctDNA were available. An optimized CEA threshold of 2 ng/mL was identified, the 3-year DFS was 66.4% for patients above the threshold and 80.9% for those below (HR, 1.74; 95% CI, 1.33-2.28, P < .001). In multivariate analysis, CEA ≥ 2 ng/mL contributed significantly to model variability, becoming an independent prognostic factor for DFS (HR, 1.82; 95% CI,1.27-2.59), alongside ctDNA (HR, 1.88; 95% CI, 1.16-3.03) and pTN (HR, 1.78; 95% CI, 1.24-2.54). A novel integrated risk classification combining CEA, ctDNA, and pTN stage reclassified 19.8% of pT4/N2 patients as low risk and 2.5% of pT3/N1 patients as high risk. This new classification demonstrated the 3-year DFS of 80.8% for low-risk patients and 55.4% for high-risk patients (HR, 2.66, 95% CI, 1.84-3.86, P < .001).

CONCLUSIONS

Postoperative CEA value is a prognostic factor for DFS in stage 3 CC, independently of ctDNA and pTN. It advocates for systematic reporting in future adjuvant trials. Integrating both biomarkers with pTN could refine risk classification in stage 3 CC.

Essential updates 2022-2023: Surgical and adjuvant therapies for locally advanced colorectal cancer

Pivotal articles that had been published between 2022 and 2023 on surgical and perioperative adjuvant treatments for locally advanced colorectal cancer (CRC) were reviewed. This review focuses on new evidence in the following areas: optimization of surgical procedures for colon cancer, including the optimal length of bowel resection and use of the no-touch isolation technique; minimally invasive surgery for rectal cancer, such as laparoscopic transanal total mesorectal excision and robotic surgery; neoadjuvant treatments for rectal cancer, including total neoadjuvant therapy; neoadjuvant chemotherapy for colon cancer; and postoperative adjuvant chemotherapy for Stage II and III colon cancer. Although the current understanding may not enable perfect decision-making for patients and medical professionals, ongoing advancements are expected to result in more effective personalized treatment plans, ultimately improving the prognosis and quality of life of patients.

Circulating tumour DNA and risk of recurrence in patients with asymptomatic versus symptomatic colorectal cancer

BACKGROUND

Multiple initiatives aim to develop circulating tumour DNA (ctDNA) tests for early cancer detection in asymptomatic individuals. The few studies describing ctDNA-testing in both asymptomatic and symptomatic patients report lower ctDNA detection in the asymptomatic patients. Here, we explore if asymptomatic patients differ from symptomatic patients e.g. by including a 'low-ctDNA-shedding' and 'less-aggressive' subgroup.

METHODS

ctDNA assessment was performed in two independent cohorts of consecutively recruited patients with asymptomatic colorectal cancer (CRC) (Cohort#1: n = 215, Cohort#2: n = 368) and symptomatic CRC (Cohort#1: n = 117, Cohort#2: n = 722).

RESULTS

After adjusting for tumour stage and size, the odds of ctDNA detection was significantly lower in asymptomatic patients compared to symptomatic patients (Cohort#1: OR: 0.4, 95%CI: 0.2-0.8, Cohort#2: OR: 0.7, 95%CI: 0.5-0.9). Further, the recurrence risk was lower in asymptomatic patients (Cohort#1: sHR: 0.6, 95%CI: 0.3-1.2, Cohort#2: sHR: 0.6, 95%CI: 0.4-1.0). Notably, ctDNA-negative asymptomatic patients had the lowest recurrence risk compared to the symptomatic patients (Cohort#1: sHR: 0.2, 95%CI: 0.1-0.6, Cohort#2: sHR: 0.3, 95%CI: 0.2-0.6).

CONCLUSIONS

Our study suggests that asymptomatic patients are enriched for a 'low-ctDNA-shedding-low-recurrence-risk' subgroup. Such insights are needed to guide ctDNA-based early-detection initiatives and should prompt discussions about de-escalation of therapy and follow-up for ctDNA-negative asymptomatic CRC patients.

ctDNA-based molecular residual disease and survival in resectable colorectal cancer

The interim analysis of the CIRCULATE-Japan GALAXY observational study demonstrated the association of circulating tumor DNA (ctDNA)-based molecular residual disease (MRD) detection with recurrence risk and benefit from adjuvant chemotherapy (ACT) in resectable colorectal cancer (CRC). This updated analysis with a 23-month median follow-up, including 2,240 patients with stage II-III colon cancer or stage IV CRC, reinforces the prognostic value of ctDNA positivity during the MRD window with significantly inferior disease-free survival (DFS; hazard ratio (HR): 11.99, P < 0.0001) and overall survival (OS; HR: 9.68, P < 0.0001). In patients who experienced recurrence, ctDNA positivity correlated with shorter OS (HR: 2.71, P < 0.0001). The significantly shorter DFS in MRD-positive patients was consistent across actionable biomarker subsets. Sustained ctDNA clearance in response to ACT was an indicator of favorable DFS and OS compared to transient clearance (24-month DFS: 89.0% versus 3.3%; 24-month OS: 100.0% versus 82.3%). True spontaneous clearance rate with no clinical recurrence was 1.9% (2/105). Overall, our findings provide evidence for the utility of ctDNA monitoring for post-resection recurrence and mortality risk stratification that could be used for guiding adjuvant therapy.

Detection of circulating tumor DNA by tumor-informed whole-genome sequencing enables prediction of recurrence in stage III colorectal cancer patients

INTRODUCTION

Circulating tumor (ctDNA) can be used to detect residual disease after cancer treatment. Detecting low-level ctDNA is challenging, due to the limited number of recoverable ctDNA fragments at any target loci. In response, we applied tumor-informed whole-genome sequencing (WGS), leveraging thousands of mutations for ctDNA detection.

METHODS

Performance was evaluated in serial plasma samples (n = 1283) from 144 stage III colorectal cancer patients. Tumor/normal WGS was used to establish a patient-specific mutational fingerprint, which was searched for in 20x WGS plasma profiles. For reproducibility, paired aliquots of 172 plasma samples were analyzed in two independent laboratories. De novo variant calling was performed for serial plasma samples with a ctDNA level > 10 % (n = 17) to explore genomic evolution.

RESULTS

WGS-based ctDNA detection was prognostic of recurrence: post-operation (Hazard ratio [HR] 6.75, 95 %CI 3.18-14.3, p < 0.001), post-adjuvant chemotherapy (HR 28.9, 95 %CI 10.1-82.8; p < 0.001), and during surveillance (HR 22.8, 95 %CI 13.7-37.9, p < 0.0001). The 3-year cumulative incidence of ctDNA detection in recurrence patients was 95 %. ctDNA was detected a median of 8.7 months before radiological recurrence. The independently analyzed plasma aliquots showed excellent agreement (Cohens Kappa=0.9, r = 0.99). Genomic characterization of serial plasma revealed significant evolution in mutations and copy number alterations, and the timing of mutational processes, such as 5-fluorouracil-induced mutations.

CONCLUSION

Our study supports the use of WGS for sensitive ctDNA detection and demonstrates that post-treatment ctDNA detection is highly prognostic of recurrence. Furthermore, plasma WGS can identify genomic differences distinguishing the primary tumor and relapsing metastasis, and monitor treatment-induced genomic changes.

Colorectal Cancer Recurrence Prediction Using a Tissue-Free Epigenomic Minimal Residual Disease Assay

PURPOSE

Posttreatment detection of ctDNA is strongly predictive of recurrence. Most minimal/molecular residual disease assays require prior tissue testing to guide ctDNA analysis, resulting in lengthy time to initial results and unevaluable patients.

EXPERIMENTAL DESIGN

We assessed a tissue-free assay (Guardant Reveal) that bioinformatically evaluates >20,000 epigenomic regions for ctDNA detection in 1,977 longitudinally collected postoperative plasma samples from 342 patients with resected colorectal cancer.

RESULTS

We observed sensitive and specific detection of minimal/molecular residual disease associated with clinically meaningful differences in recurrence-free intervals at each time point evaluated with a median lead time of 5.3 months. The longitudinal sensitivity in stage II or higher colon cancer was 81%. Sensitivity increased with serial measurement and varied by recurrence site: higher for liver (100%) versus lung (53%) and peritoneal (40%). Sensitivity among patients with rectal cancer was 60% owing to a high proportion of lung metastases. Specificity was 98.2% among 1,461 posttreatment samples (99.1% among those with follow-up longer than the upper IQR of the lead time observed in this study).

CONCLUSIONS

Our data demonstrate the potential clinical utility of ctDNA as a tool to improve the management of stage II and higher colorectal cancer with a methodology that is noninvasive, accessible, and allows for rapid evaluation to inform clinical decisions.

A review of trials investigating ctDNA-guided adjuvant treatment of solid tumors: The importance of trial design

Circulating tumor DNA (ctDNA) holds promise as a biomarker for guiding adjuvant treatment decisions in solid tumors. This review systematically assembles ongoing and published trials investigating ctDNA-directed adjuvant treatment strategies. A total of 57 phase II/III trials focusing on ctDNA in minimal residual disease (MRD) detection were identified, with a notable increase in initiation over recent years. Most trials target stage II or III colon/colorectal cancer, followed by breast cancer and non-small cell lung cancer. Trial methodologies vary, with some randomizing ctDNA-positive patients between standard-of-care (SoC) treatment and intensified regimens, while others aim to de-escalate therapy in ctDNA-negative patients. Challenges in trial design include the need for randomized controlled trials to establish clinical utility for ctDNA, ensuring adherence to standard treatment in control arms, and addressing the ethical dilemma of withholding treatment in high-risk ctDNA-positive patients. Longitudinal ctDNA surveillance emerges as a strategy to improve sensitivity for recurrence, particularly in less proliferative tumor types. However, ctDNA as longitudinal marker is often not validated yet. Ultimately, designing effective ctDNA interventional trials requires careful consideration of feasibility, meaningful outcomes, and potential impact on patient care.

State-of-the-Art Management of Colorectal Cancer: Treatment Advances and Innovation

Colorectal cancer (CRC) remains a significant global health challenge, ranking among the leading causes of cancer-related morbidity and mortality worldwide. Recent advancements in molecular characterization have revolutionized our understanding of the heterogeneity within colorectal tumors, particularly in the context of tumor sidedness. Tumor sidedness, referring to the location of the primary tumor in either the right or left colon, has emerged as a critical factor influencing prognosis and treatment responses in metastatic CRC. Molecular underpinnings of CRC, the impact of tumor sidedness, and how this knowledge guides therapeutic decisions in the era of precision medicine have led to improved outcomes and better quality of life in patients. The emergence of circulating tumor DNA as a prognostic and predictive tool in CRC heralds promising advancements in the diagnosis and monitoring of the disease. This innovation facilitates better patient selection for exploration of additional treatment options. As the field progresses, with investigational agents demonstrating potential as future treatments for refractory metastatic CRC, new avenues for enhancing outcomes in this challenging disease are emerging.

Neoadjuvant treatment of colorectal cancer: comprehensive review

BACKGROUND

Neoadjuvant therapy has an established role in the treatment of patients with colorectal cancer. However, its role continues to evolve due to both advances in the available treatment modalities, and refinements in the indications for neoadjuvant treatment and subsequent surgery.

METHODS

A narrative review of the most recent relevant literature was conducted.

RESULTS

Short-course radiotherapy and long-course chemoradiotherapy have an established role in improving local but not systemic disease control in patients with rectal cancer. Total neoadjuvant therapy offers advantages over short-course radiotherapy and long-course chemoradiotherapy, not only in terms of increased local response but also in reducing the risk of systemic relapses. Non-operative management is increasingly preferred to surgery in patients with rectal cancer and clinical complete responses but is still associated with some negative impacts on functional outcomes. Neoadjuvant chemotherapy may be of some benefit in patients with locally advanced colon cancer with proficient mismatch repair, although patient selection is a major challenge. Neoadjuvant immunotherapy in patients with deficient mismatch repair cancers in the colon or rectum is altering the treatment paradigm for these patients.

CONCLUSION

Neoadjuvant treatments for patients with colon or rectal cancers continue to evolve, increasing the complexity of decision-making for patients and clinicians alike. This review describes the current guidance and most recent developments.

Waiting for the "liquid revolution" in the adjuvant treatment of colon cancer patients: a review of ongoing trials

Since colon cancer has a high rate of shedding of tumour fragments into the blood, several research efforts are now focused on the investigation of the minimal residual disease through the detection of ctDNA to tailor the adjuvant therapy of colon cancer patients and optimize its cost/effectiveness balance. The negative prognostic impact of detectable ctDNA in patients' blood after radical surgery for colon cancer is well established. Several clinical trials adopting heterogeneous designs and techniques are now ongoing to translate promises into daily practice by answering five general questions: i) is a ctDNA-guided decision making efficacious in the post-operative management of colon cancer patients? ii) are de-escalation strategies possible in ctDNA-negative cases? iii) are escalation strategies useful to improve the prognosis of ctDNA-positive patients? iv) when MRD is identified at the end of the adjuvant chemotherapy, is another post-adjuvant systemic therapy efficacious? v) can we exploit ctDNA technologies in the follow up of colon cancer patients? This review focuses on currently ongoing trials and how their results may affect the ctDNA "liquid revolution" of early colon cancer.