Serial circulating tumour DNA analysis during multimodality treatment of locally advanced rectal cancer: a prospective biomarker study

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.

Liquid Biopsy in HPV-Associated Head and Neck Cancer: A Comprehensive Review

Objectives: Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer globally, with HPV-positive cases emerging as a distinct subtype with unique clinical and molecular characteristics. Current diagnostic methods, including tissue biopsy and imaging, face limitations in terms of invasiveness, static disease assessment, and difficulty in distinguishing recurrence from treatment-related changes. This review aimed to assess the potential of liquid biopsy as a minimally invasive tool for the diagnosis, treatment monitoring, and surveillance of HPV-associated HNSCC. Methods: This systematic review analyzed literature from PubMed/MEDLINE, Embase, and Web of Science, focusing on original research and reviews related to liquid biopsy applications in HPV-positive HNSCC. Included studies were evaluated based on the robustness of the study design, clinical relevance, and analytical performance of liquid biopsy technologies. Biomarker types, detection methods, and implementation strategies were assessed to identify advancements and challenges in this field. Results: Liquid biopsy technologies, including circulating HPV DNA, ctDNA, and extracellular vesicles, demonstrated high sensitivity (90-95%) and specificity (>98%) in detecting HPV-positive HNSCC. These methods enabled real-time monitoring of tumor dynamics, early detection of recurrence, and insights into treatment resistance. Longitudinal analysis revealed that biomarker clearance during treatment correlates strongly with patient outcomes. Conclusions: Liquid biopsy is a transformative diagnostic and monitoring tool for HPV-associated HNSCC, offering minimally invasive, real-time insights into tumor biology. While challenges remain in standardization and clinical implementation, ongoing research and technological innovations hold promise for integrating liquid biopsy into personalized cancer care, ultimately improving patient outcomes.

Rationale and design of a multicentre randomised controlled trial on circulating tumour DNA-guided neoadjuvant treatment strategy for locally advanced rectal cancer (CINTS-R)

BACKGROUND

The traditional neoadjuvant chemoradiotherapy (nCRT) combined with total mesorectal excision has been widely accepted as the standard treatment for patients with locally advanced rectal cancer (LARC). New strategies such as total neoadjuvant therapy (TNT) and neoadjuvant immunotherapy have shown great promise in certain patient populations. Currently, there is an urgent need to stratify patients before treatment to adopt the appropriate neoadjuvant strategies. Our previous study has shown that circulating tumour DNA (ctDNA) effectively reflects tumour burden and genetic characteristics and has significant predictive value for tumour recurrence, demonstrating great potential in guiding the choice of neoadjuvant strategies.

METHODS AND ANALYSIS

The CINTS-R trial is a multicentre, open-label, randomised controlled trial designed to evaluate the efficacy and safety of a ctDNA-guided neoadjuvant treatment strategy compared with conventional neoadjuvant therapy regime in patients with LARC. The trial will enrol 470 patients diagnosed with LARC (staged cT3-4N0 or cTanyN1-2) with tumours located ≤12 cm from the anal verge across seven centres in China. Patients will be randomly assigned in a 2:1 ratio to the experimental group or the control group. Patients in the experimental group will receive different intensities of neoadjuvant chemoradiotherapy (TNT or modified nCRT) or neoadjuvant immunotherapy based on the molecular features of the tumour, baseline ctDNA concentration and changes in ctDNA status early in treatment. Patients in the control group will receive modified nCRT. The primary endpoint is the 2-year disease-related treatment failure rate. The secondary endpoints include time to recurrence, 2-year overall survival, 2-year disease-free survival, clinical complete response (cCR) rate, near cCR rate and pathologically complete response rate, pathological tumour regression grade and quality of life.

ETHICS AND DISSEMINATION

This protocol has been approved by the ethics committee of Peking Union Medical College Hospital, with approval number I-23PJ157, and by the institutional review boards of all the participating centres. All data will be collected and stored in a specially designed database. The results of our trial will be disseminated through peer-reviewed publications and presented at national and international academic conferences.

TRIAL REGISTRATION NUMBER

This trial is registered on ClinicalTrials.gov and the registration ID is NCT05601505.

Circulating DNA in Rectal Cancer to Unravel the Prognostic Potential for Radiation Oncologist: A Meta-analysis

OBJECTIVES

Liquid biopsy, with its noninvasive nature and ability to detect tumor-specific genetic alterations, emerges as an ideal biomarker for monitoring recurrences for locally advanced rectal cancer (LARC). Completed studies have small sample sizes and different experimental methods. To consolidate and assess the collective evidence regarding the prognostic role of circulating DNA (ctDNA) detection in LARC patients undergoing neoadjuvant chemoradiotherapy (nCRT).

METHODS

Computerized bibliographic searches of MEDLINE and CANCERLIT (2000 to 2023) were supplemented with hand searches of reference lists. Study selection: studies evaluating oncological outcomes of patients with LARC treated with a nCRT comparing patients with positive and negative liquid biopsy at baseline and after nCRT. Data extraction: data on population, intervention, and outcomes were extracted from each study, in accordance with the intention to treat method, by 2 independent observers, and combined using the DerSimonian method and Laird method.

RESULTS

Nine studies follow inclusion criteria including 678 patients treated with nCRT. The pooled RD rate of ctDNA negative between measure at baseline and after nCRT is statistically significant 61% (95% CI: 53-70, P =0.0002). The hazard ratio (HR) of progression-free survival between ct-DNA negative and positive is significant 7.41 (95% CI: 4.87-11.289, P <0.00001).

CONCLUSIONS

ctDNA can identify patients with different recurrence risks following nCRT and assess prognosis in patients with LARC. Further prospective study is necessary to determine the utility of ctDNA in personalised therapy for patients with LARC.

Circulating tumour DNA in predicting and monitoring survival of patients with locally advanced rectal cancer undergoing multimodal treatment: long-term results from a prospective multicenter study

BACKGROUND

Neoadjuvant chemoradiotherapy (nCRT) is the standard for locally advanced rectal cancer (LARC). However, distant metastasis remains the primary cause of treatment failure. Early identification of high-risk individuals for personalized treatment may offer a solution. Circulating tumour DNA (ctDNA) could assist in this process.

METHODS

From September 2017 to June 2019, the study prospectively recruited 113 patients with LARC (cT3-4N0M0 or cTanyN + M0) who underwent nCRT followed by radical surgery across 8 tertiary centers. ctDNA was analysed using large-panel targeted sequencing at baseline, during nCRT, pre-surgery, post-surgery, post-adjuvant chemotherapy (ACT), and during annual follow-ups for 3 years.

FINDINGS

We analysed 103 tissue and 669 plasma samples from 103 patients. With a median 53-month follow-up, significantly worse progression-free survival (PFS) and overall survival (OS) were observed if median variant allele frequency (mVAF) of baseline ctDNA per patient was ≥0.5% (PFS, HR 4.39, p < 0.001; OS, HR 5.61, p = 0.004) or ctDNA was still detectable two weeks into nCRT (PFS, HR 7.63, p < 0.001; OS, HR 5.08, p < 0.001). Furthermore, when compared to the low-risk (C1) group (characterized by "ctDNA undetected during nCRT with baseline mVAF <0.5%" or "ctDNA undetected during nCRT with TMB (tumour mutational burden) ≥20/Mb"), the high-risk (C2) group (characterized by "ctDNA detected during nCRT" or "baseline mVAF ≥0.5% with TMB <20/Mb") showed significantly worse long-term outcomes (3 y-PFS, 55.9% vs. 94.2%; 3 y-OS, 79.4% vs. 100%). The ctDNA clearance during nCRT, baseline mVAF, and TMB may be effective prognostic indicators.

INTERPRETATION

Our findings reaffirm the clinical monitoring value of ctDNA and demonstrate the strong prognostic value of baseline ctDNA and its early clearance status in patients with LARC undergoing nCRT. This highlights the potential of dynamic ctDNA monitoring as actionable stratified indicators to guide personalized neoadjuvant treatment strategies.

FUNDING

This work was supported by the Major Grants Program of Beijing Science and Technology Commission (No. D171100002617003) and the National High Level Hospital Clinical Research Funding (2022-PUMCH-C-005).

Circulating Tumor DNA Testing for Minimal Residual Disease and Its Application in Colorectal Cancer

Colorectal cancer (CRC) represents a heterogeneous group of diseases that imposes a considerable global and national health burden. Although most CRC patients are diagnosed at an early stage and undergo potentially curative treatment, a significant proportion experience recurrence. Currently, adjuvant chemotherapy decisions are primarily based on clinicopathological characteristics, which have well-recognized limitations in accurately identifying patients harboring minimal residual disease (MRD), often resulting in unnecessary chemotherapy exposure. Circulating tumor DNA (ctDNA) has emerged as a promising surrogate marker for MRD, offering a more precise approach to identifying patients at risk of recurrence after curative-intent surgery and refining adjuvant chemotherapy decisions. Growing evidence from multiple studies has demonstrated that ctDNA outperforms traditional clinicopathological factors as a marker for MRD. This review synthesizes key studies supporting the role of ctDNA in MRD detection for CRC patients and evaluates clinical trials investigating the application of ctDNA in guiding adjuvant therapy decisions. This emerging strategy holds the potential to transform the adjuvant treatment paradigm in colorectal cancer by optimizing therapeutic precision and minimizing unnecessary treatment.

A Comprehensive Approach to Neoadjuvant Treatment of Locally Advanced Rectal Cancer

At the end of the past century, the introduction of Total Mesorectal Excision (TME), preceded by either short-course radiotherapy (SCRT) or chemoradiation (CRT), established the new standard of care for locally advanced rectal cancer (LARC). Recently, significant advancements were achieved for both dMMR/MSI and pMMR/MSS LARC patients. For the 2-3% of dMMR/MSI LARCs, ablative immunotherapy emerged as a curative approach, offering the possibility of avoiding chemotherapy (CT), radiotherapy, and surgery altogether. In pMMR/MSS LARCs, the intensification of preoperative treatments with Total Neoadjuvant Treatment (TNT) afforded three outcomes: (a) a reduction of distant metastases, positively impacting on survival endpoints, (b) a significant increase of complete clinical response (cCR) rate, paving the way for non-operative management (NOM), and (c) the selective omission of radiotherapy following induction CT. The choice of the most appropriate therapeutic strategy can only be made through the shared decision-making process between physician and patient based on risk stratification and patient preferences.

A non-randomised open-label exploratory 'window of opportunity' study of TG02 treatment in patients with locally advanced primary and recurrent RAS mutant colorectal cancer

Background

TG02 is a peptide-based cancer vaccine eliciting immune responses to oncogenic codon 12/13 RAS mutations. This phase 1 clinical trial (NCT02933944) assessed the safety and immunological efficacy of TG02 adjuvanted by GM-CSF in patients with KRAS-mutant colorectal cancer.

Methods

In the interval between completing CRT and pelvic exenteration, patients with resectable KRAS mutation-positive, locally advanced primary or current colorectal cancer, received 5-6 doses of TG02/GM-CSF. Immune response was defined as a positive delayed-type hypersensitivity or positive T cell proliferation assay response. Tumour biopsies were analysed for tumour-infiltrating lymphocytes (TILs) and blood for CEA and ctDNA. TILs and tumouroids were cultured, characterised and tested for their killing efficacy.

Results

Six patients with rectal cancer were recruited to evaluate TG02. Three patients experienced a total of 16 treatment-related adverse events; all grade 1. Four of the 6 patients (66.7 %) had at least one vaccine-induced TG02 immune response. Flow cytometry analysis showed high proportion of PD-1-expressing TILs in 2 of 3 patient specimens' post-treatment. A partial to near complete pathological response was reported in 4 of 6 patients.

Conclusions

This study demonstrated that TG02/GM-CSF was well tolerated and induced a vaccine specific systemic immune response in the majority of patients. Low numbers limit conclusive clinical outcome reporting. High PD-1 expression on post-treatment TILs encourages the addition of an immune checkpoint inhibitor to TG02 and potentially other studies of peptide vaccines in future studies.

Longitudinal circulating tumor DNA monitoring in predicting response to short-course radiotherapy followed by neoadjuvant chemotherapy and camrelizumab in locally advanced rectal cancer: data from a Phase Ⅲ clinical trial (UNION)

This study, conducted as part of a multicenter phase III clinical trial, aimed to assess the utility of circulating tumor DNA (ctDNA)-based minimal residual disease (MRD) in comparing the efficacy of short-course and long-course chemoradiotherapy (CRT) for locally advanced rectal cancer (LARC). A total of 244 plasma samples from 79 LARC patients undergoing neoadjuvant therapy (NAT) before surgery were collected at various time points. Targeted deep sequencing using a novel MRD panel was performed. During NAT, ctDNA levels declined significantly. Baseline ctDNA-MRD status did not correlate significantly with treatment response. Notably, compared to long-course radiotherapy, microsatellite instability increased significantly after short-course radiotherapy (shortRT). Additionally, ctDNA negativity or lower levels were significantly associated with pathological complete response (pCR). Clearance of ctDNA and MRD after shortRT correlated significantly with pCR. A predictive model based on ctDNA-MRD, combined with carcinoembryonic antigen (CEA), outperformed models using only MRD or only CEA in predicting pCR/non-pCR. These findings provide insights into NAT for LARC and highlight ctDNA-based MRD assessment's potential in tailoring treatment strategies, emphasizing the need for personalized approaches.

Introducing Neoadjuvant Immunotherapy for Colorectal Cancer: Advancing the Frontier

OBJECTIVE

To give surgeons a review of the current and future use of neoadjuvant immunotherapy in patients with localized colorectal cancer (CRC).

BACKGROUND

Immunotherapy has revolutionized the standard of care in oncology and improved survival outcomes in several cancers. However, the applicability of immunotherapy is still an ongoing challenge. Some cancer types are less responsive to immunotherapy, and the heterogeneity in responses within cancer types is poorly understood. Clinical characteristics of the patient, the timing of immunotherapy in relation to surgery, diversities in the immune responses, clonal heterogeneity, different features of the tumor microenvironment, and genetic alterations are some factors among many that may influence the efficacy of immunotherapy.

RESULTS

In this narrative review, we describe the major types of immunotherapy used to treat localized CRC. Furthermore, we discuss the prediction of response to immunotherapy in relation to biomarkers and radiologic assessment. Finally, we consider the future perspectives of clinical implications and response patterns, as well as the potential and challenges of neoadjuvant immunotherapy in localized CRC.

CONCLUSIONS

Establishing mismatch repair (MMR) status at the time of diagnosis is central to the potential use of neoadjuvant immunotherapy, in particular immune checkpoint inhibitors, in localized CRC. To date, efficacy is primarily seen in patients with deficient MMR status and polymerase epsilon mutations, although a small group of patients with proficient MMR does respond. In conclusion, neoadjuvant immunotherapy shows promising complete response rates, which may open a future avenue of an organ-sparing watch-and-wait approach for a group of patients.

The Role of Pulmonary Metastasectomy for Non-Primary Lung Cancer: Umbrella Review of Meta-Analyses

BACKGROUND AND OBJECTIVES

Due to heterogeneous characteristics of primary cancers, the efficacy of pulmonary metastasectomy (PM) in nonprimary lung cancers has not been investigated. This study aims to investigate the clinical outcomes of PM for non-primary lung cancer.

METHODS

A systematic search for meta-analyses on PM for nonprimary lung cancers was conducted, encompassing publications up to January 3, 2024. This included seven primary cancers: renal cell, breast, adrenocortical, head and neck cancers, melanoma, germ cell tumors, and sarcoma. Overall survival and recurrence rates post-PM were assessed using random-effect models.

RESULTS

This study included 16 systematic-review articles and 101 individual studies, involving 10 277 patients who underwent PM for nonprimary lung cancer. About half of the patients (47.1%) presented with multiple metastasis, and complete resection achieved in 87.2% [95% CI: 83.0-90.8]. The pooled 5-year overall survival rate post-PM was 41.2% [95%CI: 37.1%-45.4%]. Patients with germ cell tumors demonstrated higher survival rate (p < 0.05), while melanoma exhibited the worst outcome (p < 0.05). During follow-up, 57.6% [95% CI: 46.4-68.1] had recurrence; 48% of them had intrathoracic-only recurrence.

CONCLUSION

This study underscores the survival benefits associated with PM. Overall survival rates following PM did not differ based on primary cancer types. These findings highlight the importance of recognizing and incorporating PM into clinical practice when appropriate.

Circulating Tumor DNA for Prediction of Complete Pathological Response to Neoadjuvant Radiochemotherapy in Locally Advanced Rectal Cancer (NEORECT Trial)

BACKGROUND/OBJECTIVES

Locally advanced rectal cancer is treated with neoadjuvant chemoradiotherapy (nCRT) followed by total mesorectal excision (TME). As this approach achieves complete pathologic remissions (pCR) in approximately 30% of patients, it raises the question of whether surgery is always necessary. Non-surgical strategies, such as "watch and wait" (W&W), have shown similarly promising outcomes. However, there is an unmet need for reliable biomarkers predicting pCR. Analysis of circulating tumor DNA (ctDNA) has shown potential for monitoring treatment response and detecting minimal residual disease. We hypothesized that monitoring ctDNA changes during nCRT might facilitate the identification of individuals who achieve pCR.

METHODS

In the prospective single-center NEORECT trial, the plasma of forty rectal cancer patients was collected before, during, and after nCRT and before TME. Informative somatic mutations were identified in tissue biopsies by NGS and subsequently used for ctDNA quantification by dPCR.

RESULTS

The results identified three distinct ctDNA patterns: increase, decrease, and absence. Remarkably, undetectable DNA was observed in good responders, while a tenfold ctDNA increase was associated with the emergence of new metastases. Despite these insights, ctDNA alone demonstrated low specificity, with no significant correlation to pCR or long-term prognosis. A multimodal approach incorporating routinely available clinical parameters remains inadequate for accurately predicting pCR prior to TME.

CONCLUSIONS

In conclusion, the NEORECT trial establishes the feasibility of ctDNA-based personalized monitoring for rectal cancer patients undergoing nCRT. However, the utility of ctDNA in enhancing pCR prediction for a W&W strategy warrants further investigation. Larger studies integrating multi-gene analyses and expanded clinical datasets are essential in the future.

Landscape of Biomarkers and Pathologic Response in Rectal Cancer: Where We Stand?

Colorectal cancer (CRC) is a neoplasm with a high prevalence worldwide, with a multimodal treatment that includes a combination of chemotherapy, radiotherapy, and surgery in locally advanced stages with acceptable pathological complete response (pCR) rates, this has improved with the introduction of total neoadjuvant therapy (TNT) reaching pCR rates up to 37% in compare with classic neoadjuvant treatment (NAT) where pCR rates of around 20-25% are achieved. However, the patient population that benefits most from this therapy has not been determined, and there is a lack of biomarkers that can predict the course of the disease. Multiple biomarkers have been studied, ranging from hematological and molecular markers by imaging technique and combinations of them, with contradictory results that prevent their use in routine clinical practice. In this review, we evaluate the most robust prognostic biomarkers to be used in clinical practice, highlighting their advantages and disadvantages and emphasizing biomarker combinations and their predictive value.

Circulating Tumor DNA Testing in Curatively Resected Colorectal Cancer and Salvage Resection

Importance

Serial circulating tumor DNA (ctDNA) has emerged as a routine surveillance strategy for patients with resected colorectal cancer, but how serial ctDNA monitoring is associated with potential curative outcomes has not been formally assessed.

Objective

To examine whether there is a benefit of adding serial ctDNA assays to standard-of-care imaging surveillance for potential curative outcomes in patients with resected colorectal cancer.

Design, Setting, and Participants

In this single-center (City of Hope Comprehensive Cancer Center, Duarte, California), retrospective, case cohort study, patients with stage II to IV colorectal cancer underwent curative resection and were monitored with serial ctDNA assay and National Cancer Center Network (NCCN)-guided imaging surveillance from September 20, 2019, to April 3, 2024. The median duration of follow-up was 26 months (range, 2-54 months).

Interventions

Serial ctDNA assays were performed every 3 months for 2 years and every 6 months for the 3 following years in conjunction with NCCN-guided radiographic surveillance.

Main Outcomes and Measures

The primary outcome was the proportion of patients with clinical benefit from ctDNA testing, defined as the proportion of patients with a newly positive ctDNA assay and negative scheduled imaging (most recent or concurrent) that subsequently led to early imaging confirmation of recurrence, followed by curative-intent intervention with no evidence of recurrence at the time of data cutoff. Recurrence was categorized by ctDNA recurrence, radiographic recurrence, or concurrent ctDNA and imaging recurrence. Salvage resections and associated durable remissions were described within each of the 3 categories. Descriptive statistics were used to characterize the patient population.

Results

In total, 184 patients (median age, 59 years [range, 32-88 years]; 97 female [52.7%]) were included in this study, and 129 (70.1%) had stage II to III disease. Forty-five patients (24.5%) had ctDNA or imaging-confirmed recurrence. Of these 45 patients, 14 had radiographic recurrence with negative ctDNA, and 11 had concurrent ctDNA and imaging recurrence. Twenty of 45 patients had ctDNA positivity with negative imaging at first ctDNA positivity; 6 had reflex imaging that was positive for recurrence, and 14 continued with serial imaging and ctDNA monitoring. Ten of 14 patients had subsequent recurrent disease, 3 patients had a spontaneous clearance of ctDNA, and 1 patient remained imaging negative 7 months after positive ctDNA, after which she was lost to follow-up. Altogether, 11 of 20 patients with ctDNA recurrence without initial concurrent imaging recurrence had subsequent metastasectomy, and only 3 were disease-free at the cutoff date in April 2024, representing 1.6% of the surveilled population.

Conclusions and Relevance

In this cohort study of patients with stage II to IV colorectal cancer who underwent curative-intent resection, the addition of serial tumor-informed ctDNA assay to the standard NCCN-recommended surveillance had limited clinical benefits. Additional prospective research is needed to clarify the value of ctDNA testing in the surveillance setting.

Assessment of circulating tumor DNA in patients with locally advanced rectal cancer treated with neoadjuvant therapy

Post-neoadjuvant therapy (post-NAT) and post-surgical circulating tumor DNA (ctDNA) risk stratification may enhance the management of patients with locally advanced rectal cancer (LARC). In this study, we assessed the prognostic value of ctDNA-based MRD detection in LARC patients using a personalized, tumor-informed ctDNA assay. Plasma samples from LARC patients (N = 30) were analyzed retrospectively using the Signatera™ assay. The neoadjuvant rectal (NAR) score was calculated and compared to ctDNA status to predict recurrence risk and survival outcomes. ctDNA-positive patients post-NAT and post-surgery had worse Disease Free Survival (DFS) (HR: 7.82; p = 0.001, HR: 19.65; p = 0.001) when compared to ctDNA-negative patients. In the post-NAT setting, patients who responded to NAT had superior DFS compared to patients who did not clear their ctDNA or showed no radiological response (HR: 24.7, p = 0.001 and HR: 5.1, p = 0.054, respectively). When ctDNA status is used alongside the NAR score in the post-NAT setting, patients who were ctDNA-positive with an intermediate or high NAR score showed significantly worse DFS (HR: 47.5, p < 0.001) compared to ctDNA-negative patients with either a low or intermediate/high NAR score (HR: 9.8, p = 0.0301). Post-NAT ctDNA status, whether used alone or in combination with the NAR score, may predict NAT response, and improve risk stratification.

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.

Dynamics of cell-free tumor DNA correlate with early MRI response during chemoradiotherapy in rectal cancer

BACKGROUND

In locally advanced rectal cancer, the prediction of tumor response during and after neoadjuvant treatment remains challenging. In terms of organ preservation, adaptive radiotherapy, and intensified (total) neoadjuvant therapies, biomarkers are desirable for patient stratification.

METHODS

In 16 patients, weekly blood samples (n = 86) to detect cell-free tumor DNA (ctDNA) during long-course neoadjuvant chemoradiotherapy were analyzed. Data were correlated with initial tumor volumes, MRI response in week 2 and 5 of radiotherapy as well as with pathologic tumor response after resection and outcome parameters.

RESULTS

Most patients showed decreasing ctDNA during the course of radiochemotherapy. However, we found heterogenous dynamics of ctDNA and could identify three groups: (1) decline (2) no clear decline and/or late shedding (3) persistence of ctDNA. In seven patients we could detect significant amounts of ctDNA in week 5 or week 6 of treatment. In our pilot cohort, we did not find significant correlations of ctDNA dynamics with pathologic response or outcome parameters. However, patients with distinct decline of ctDNA had larger tumor volumes prior to treatment, and MRI imaging in week 2 and 5 revealed bigger absolute decrease of tumor volumes. If significant levels of ctDNA were found in week 5 and / or 6, patients showed less absolute tumor volume decrease in week 2 and 5.

CONCLUSIONS

Weekly measurement of ctDNA during radiochemotherapy is feasible and might represent a promising biomarker. Bigger initial primary tumors showed different ctDNA shedding profiles compared with smaller primary tumors and correlations of ctDNA dynamics with early imaging response were found.

Perioperative Use of ctDNA to Guide Treatment for Urothelial Carcinoma: The Future is Now

 Muscle-invasive bladder cancer represents a potentially curable disease, yet often disease recurs and is ultimately fatal. Outcomes for patients with localized urothelial carcinoma are heterogeneous with some patients cured with surgery alone, deriving no benefit from perioperative systemic therapy, while others are left with residual disease and may benefit from additional therapy. Neoadjuvant chemotherapy increases cure rates but comes with significant toxicity. Recently, adjuvant nivolumab has demonstrated significant improvement in disease free survival (DFS), and overall survival analysis is pending. With more therapies approved for urothelial cancer within the last 5 years than ever before, there is incredible potential to improve clinical outcomes and potentially cure more patients with integrated multimodal therapy. Biomarkers are needed to dichotomize those most likely to benefit from perioperative systemic therapy for residual disease, and de-escalate therapy for those likely to be cured with surgery alone. Ultrasensitive assays for circulating tumor DNA (ctDNA) have emerged as a method to identify patients at high risk of recurrence after definitive therapy and may benefit from escalated therapy, while also identifying those least likely to benefit from systemic therapy. Studies have demonstrated that the presence of ctDNA after surgery is prognostic of disease recurrence across multiple cancer types, including bladder cancer, but questions remain as to the utility of these tests, and whether they can be predictive of benefit of adjuvant therapy. Although these liquid biopsies hold significant promise to transform perioperative treatment, prospective studies are needed to validate their utility as prognostic and predictive biomarkers. To bridge this knowledge gap, contemporary clinical trials are incorporating ctDNA as an integral biomarker to guide therapy for MIBC.

Circulating tumour DNA in patients with hepatocellular carcinoma across tumour stages and treatments

OBJECTIVE

Circulating tumour DNA (ctDNA) is a promising non-invasive biomarker in cancer. We aim to assess the dynamic of ctDNA in patients with hepatocellular carcinoma (HCC).

DESIGN

We analysed 772 plasmas from 173 patients with HCC collected at the time of diagnosis or treatment (n=502), 24 hours after locoregional treatment (n=154) and during follow-up (n=116). For controls, 56 plasmas from patients with chronic liver disease without HCC were analysed. All samples were analysed for cell free DNA (cfDNA) concentration, and for mutations in TERT promoter, CTNNB1, TP53, PIK3CA and NFE2L2 by sequencing and droplet-based digital PCR. Results were compared with 232 corresponding tumour samples.

RESULTS

In patients with active HCC, 40.2% of the ctDNA was mutated vs 14.6% in patients with inactive HCC and 1.8% in controls (p<0.001). In active HCC, we identified 27.5% of mutations in TERT promoter, 21.3% in TP53, 13.1% in CTNNB1, 0.4% in PIK3CA and 0.2% in NFE2L2, most of the times similar to those identified in the corresponding tumour. CtDNA mutation rate increased with advanced tumour stages (p<0.001). In 103 patients treated by percutaneous ablation, the presence and number of mutations in the ctDNA before treatment were associated with higher risk of death (p=0.001) and recurrence (p<0.001). Interestingly, cfDNA concentration and detectable mutations increased 24 hours after a locoregional treatment. Among 356 plasmas collected in 53 patients treated by systemic treatments, we detected mutations at baseline in 60.4% of the cases. In patients treated by atezolizumab-bevacizumab, persistence of mutation in ctDNA was associated with radiological progression (63.6% vs 36.4% for disappearance, p=0.019). In two patients progressing under systemic treatments, we detected the occurrence of mutations in CTNNB1 in the plasma that was subclonal in the tumour for one patient and not detectable in the tumour for the other one.

CONCLUSION

ctDNA offers dynamic information reflecting tumour biology. It represents a non-invasive tool useful to guide HCC clinical management.

The potential of an artificial intelligence for diagnosing MRI images in rectal cancer: multicenter collaborative trial

BACKGROUND

An artificial intelligence-based algorithm we developed, mrAI, satisfactorily segmented the rectal tumor, rectum, and mesorectum from MRI data of rectal cancer patients in an initial study. Herein, we aimed to validate mrAI using an independent dataset.

METHODS

We utilized MRI images collected in another nationwide research project, "Open versus Laparoscopic Surgery for Advanced Low Rectal Cancer Patients". MRIs from 467 cases with upfront surgery were utilized; six radiologists centralized the MRI evaluations. The diagnostic accuracies of mrAI and the radiologists for tumor depth were compared using pathologic diagnosis as a reference.

RESULTS

For all cases, centralized diagnosis demonstrated 84.2% sensitivity, 37.7% specificity, and 73.7% accuracy; mrAI exhibited 70.6% sensitivity, 61.3% specificity, and 68.5% accuracy. After limiting MRIs to those acquired by a Philips scanner, with an inter-slice spacing of ≤ 6 mm-both conditions similar to those used in the development of mrAI-the performance of mrAI improved to 76.8% sensitivity, 76.7% specificity, and 76.7% accuracy, while the centralized diagnosis showed 81.8% sensitivity, 36.7% specificity, and 71.3% accuracy. Regarding relapse-free survival, the prognosis for tumors staged ≥ T3 was significantly worse than for tumors staged ≤ T2 (P = 0.0484) in the pathologic diagnosis. While no significant difference was observed between ≥ T3 and ≤ T2 tumors in the centralized diagnosis (P = 0.1510), the prognosis for ≥ T3 was significantly worse in the mrAI diagnosis (P = 0.0318).

CONCLUSION

Proper imaging conditions for MRI can enhance the accuracy of mrAI, which has the potential to provide feedback to radiologists without overestimating tumor stage.

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.

ctDNA responds to neoadjuvant treatment in locally advanced rectal cancer

BACKGROUND

Liquid biopsy is a minimally invasive procedure investigating tumor mutations.

METHODS

In our retrospective study, we investigated whether molecular therapy monitoring of patients receiving neoadjuvant radio(chemo)therapy on a daily routine is possible in 17 patients with locally advanced rectal cancer. Six patients received short-course radiotherapy (5 × 5 Gy) with subsequent surgery, six patients were treated according RAPIDO protocol with short-course radiotherapy followed by chemotherapy (FOLFOX4) and subsequent surgery and five patients received conventional neoadjuvant radiochemotherapy with 5-FU followed by surgery. Response was assessed by Dworak. Liquid biopsies were taken before and immediately after neoadjuvant radiotherapy to isolate and ultradeeply sequence cell free DNA with a panel of 127 genes. Somatic mutations were determined bioinformatically by comparison with normal DNA from leukocytes to distinguish them from germline variants or aging mutations.

RESULTS

In 12 patients (71%) at least one somatic mutation was detected. In 8/12 patients a decrease and in 4/12 an increase or mixed response in ctDNA was seen. Statistical correlation between ctDNA analysis and clinical response could not be seen.

CONCLUSION

ctDNA is responding to neoadjuvant therapy and liquid biopsy is easily integrated into a daily routine. As part of translational research this protocol leaves room for further investigations.

Association of post-operative ctDNA detection with outcomes of patients with early breast cancers

BACKGROUND

In early breast cancer (EBC) patients, we aimed to determine whether circulating tumor DNA (ctDNA) analysis following primary surgery, before systemic therapy, identified molecular residual disease and was associated with risk of relapse and relapse-free survival (RFS).

METHODS

Plasma was collected, retrospectively, before surgery, 1-14 weeks post-operatively, and before adjuvant therapy, and in a subset of patients after adjuvant therapy. A personalized, tumor-informed, multiplex PCR next generation sequencing assay (Signatera™) was used for ctDNA detection and quantification. The primary objective was to compare RFS and distant recurrence-free survival (DRFS) in patients with detected versus non-detected ctDNA.

RESULTS

A total of 48 patients with EBC (median age 50.5 years) [34 hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-), 5 HER2+, 9 triple-negative breast cancer) were included. ctDNA was detected in 64.5% (20/31) of patients before surgery, and 35.4% (17/48) after surgery. ctDNA detection before surgery was associated with tumor grade (P = 0.019), ctDNA detection after surgery was associated with receptor subtype (P = 0.01). Patients with ctDNA detected after surgery had worse DRFS [hazard ratio = 5.5, 95% confidence interval (CI) 1.1-28.5, P = 0.04]. RFS in patients with ctDNA detected after surgery was worse than in those with lack of ctDNA detection, although not statistically significant (hazard ratio = 3.7, 95% CI 0.9-15.7, P = 0.073). Patients with ctDNA detected preoperatively or post-operatively had a trend towards worse RFS (hazard ratio = 7.8, 95% CI 0.9-63.7, P = 0.05) and DRFS (hazard ratio = 6.8, 95% CI 0.8-57, P = 0.07) compared with those with ctDNA undetected at both timepoints. ctDNA detection anticipated clinical relapse with a median lead time of 16 months.

CONCLUSIONS

In patients with treatment-naive EBC, ctDNA is detectable after surgery. The absence of ctDNA at a single post-surgical timepoint is associated with improved DRFS, supporting the development of future trials studying de-escalation of systemic therapy.

A comprehensive overview of liquid biopsy applications in pediatric solid tumors

Liquid biopsies are emerging as an alternative source for pediatric cancer biomarkers with potential applications during all stages of patient care, from diagnosis to long-term follow-up. While developments within this field are reported, these mainly focus on dedicated items such as a specific liquid biopsy matrix, analyte, and/or single tumor type. To the best of our knowledge, a comprehensive overview is lacking. Here, we review the current state of liquid biopsy research for the most common non-central nervous system pediatric solid tumors. These include neuroblastoma, renal tumors, germ cell tumors, osteosarcoma, Ewing sarcoma, rhabdomyosarcoma and other soft tissue sarcomas, and liver tumors. Within this selection, we discuss the most important or recent studies involving liquid biopsy-based biomarkers, anticipated clinical applications, and the current challenges for success. Furthermore, we provide an overview of liquid biopsy-based biomarker publication output for each tumor type based on a comprehensive literature search between 1989 and 2023. Per study identified, we list the relevant liquid biopsy-based biomarkers, matrices (e.g., peripheral blood, bone marrow, or cerebrospinal fluid), analytes (e.g., circulating cell-free and tumor DNA, microRNAs, and circulating tumor cells), methods (e.g., digital droplet PCR and next-generation sequencing), the involved pediatric patient cohort, and proposed applications. As such, we identified 344 unique publications. Taken together, while the liquid biopsy field in pediatric oncology is still behind adult oncology, potentially relevant publications have increased over the last decade. Importantly, steps towards clinical implementation are rapidly gaining ground, notably through validation of liquid biopsy-based biomarkers in pediatric clinical trials.

Trial Protocol of a Phase II Study of mFOLFOXIRI after Metastasectomy in Patients with Oligometastatic Colorectal Cancer (FANTASTIC Study)

Background

The survival benefit of adjuvant chemotherapy after surgical resection of oligometastases from colorectal cancer (CRC) remains unclear. The prognostic role of circulating-tumor DNA (ctDNA) was reported recently and a risk stratification strategy based on monitoring minimal/molecular residual disease (MRD) has been proposed, however, which drug regimen is most effective for ctDNA-positive patients is unknown.

Methods/Design

Oligometastatic CRC patients planning to undergo surgery were registered in this study. After metastasectomy, the registered patients were enrolled in the treatment arm, in which 8 courses of modified-FOLFOXIRI (mFOLFOXIRI; irinotecan 150 mg/m2, oxaliplatin 85 mg/m2, l-leucovorin (l-LV) 200 mg/m2, and 46-h continuous infusion of 5-fluorouracil (5-FU) 2400 mg/m2 every 2 weeks) followed by 4 courses of 5-FU/l-LV are administered. The patients who did not meet the eligibility criteria for the treatment arm or did not consent to mFOLFOXIRI enrolled in the observation arm in which standard of care treatment is provided. Prospective blood collections for retrospective ctDNA analysis are scheduled pre-surgery, and at 28 days, 4 and 7 months after surgery. The primary endpoint is treatment compliance at 8 courses of mFOLFOXIRI and the key secondary endpoints are the ctDNA-positivity rate and survival outcomes in ctDNA-positive and -negative groups. A total of 85 patients will be enrolled from 11 institutions. First patient-in was on July 2020. Accrual completed in February 2024.

Discussion

This study will potentially identify a better treatment strategy for patients with resectable oligometastatic CRC having postsurgical ctDNA positivity, compared to the current standard of care approaches.

Alliance A022104/NRG-GI010: The Janus Rectal Cancer Trial: a randomized phase II/III trial testing the efficacy of triplet versus doublet chemotherapy regarding clinical complete response and disease-free survival in patients with locally advanced rectal cancer

BACKGROUND

Recent data have demonstrated that in locally advanced rectal cancer (LARC), a total neoadjuvant therapy (TNT) approach improves compliance with chemotherapy and increases rates of tumor response compared to neoadjuvant chemoradiation (CRT) alone. They further indicate that the optimal sequencing of TNT involves consolidation (rather than induction) chemotherapy to optimize complete response rates. Data, largely from retrospective studies, have also shown that patients with clinical complete response (cCR) after TNT may be managed safely with the watch and wait approach (WW) instead of preemptive total mesorectal resection (TME). However, the optimal consolidation chemotherapy regimen to achieve cCR has not been established, and a randomized clinical trial has not robustly evaluated cCR as a primary endpoint. Collaborating with a multidisciplinary oncology team and patient groups, we designed this NCI-sponsored study of chemotherapy intensification to address these issues and to drive up cCR rates, to provide opportunity for organ preservation, improve quality of life for patients and improve survival outcomes.

METHODS

In this NCI-sponsored multi-group randomized, seamless phase II/III trial (1:1), up to 760 patients with LARC, T4N0, any T with node positive disease (any T, N +) or T3N0 requiring abdominoperineal resection or coloanal anastomosis and distal margin within 12 cm of anal verge will be enrolled. Stratification factors include tumor stage (T4 vs T1-3), nodal stage (N + vs N0) and distance from anal verge (0-4; 4-8; 8-12 cm). Patients will be randomized to receive neoadjuvant long-course chemoradiation (LCRT) followed by consolidation doublet (mFOLFOX6 or CAPOX) or triplet chemotherapy (mFOLFIRINOX) for 3-4 months. LCRT in both arms involves 4500 cGy in 25 fractions over 5 weeks + 900 cGy boost in 5 fractions with a fluoropyrimidine (capecitabine preferred). Patients will undergo assessment 8-12 (± 4) weeks post-TNT completion. The primary endpoint for the phase II portion will compare cCR between treatment arms. A total number of 312 evaluable patients (156 per arm) will provide statistical power of 90.5% to detect a 17% increase in cCR rate, at a one-sided alpha = 0.048. The primary endpoint for the phase III portion will compare disease-free survival (DFS) between treatment arms. A total of 285 DFS events will provide 85% power to detect an effect size of hazard ratio 0.70 at a one-sided alpha of 0.025, requiring enrollment of 760 patients (380 per arm). Secondary objectives include time-to event outcomes (overall survival, organ preservation time and time to distant metastasis) and adverse event rates. Biospecimens including archival tumor tissue, plasma and buffy coat, and serial rectal MRIs will be collected for exploratory correlative research. This study, activated in late 2022, is open across the NCTN and had accrued 330 patients as of May 2024. Study support: U10CA180821, U10CA180882, U24 CA196171; https://acknowledgments.alliancefound.org .

DISCUSSION

Building on data from modern day rectal cancer trials and patient input from national advocacy groups, we have designed The Janus Rectal Cancer Trial studying chemotherapy intensification via a consolidation chemotherapy approach with the intent to enhance cCR and DFS rates, increase organ preservation rates, and improve quality of life for patients with rectal cancer.

TRIAL REGISTRATION

Clinicaltrials.gov ID: NCT05610163; Support includes U10CA180868 (NRG) and U10CA180888 (SWOG).

Surveillance after Total Neoadjuvant Therapy: What to do for Near-Complete Responders

A proportion of patients who undergo total neoadjuvant therapy for rectal cancer will achieve what is classified as a near-complete response. Significant debate exists as to the optimal management strategy for these patients with large heterogeneity in management. This article will examine the therapeutic and surveillance options for these patients as well as the relevant outcomes data.

The Role of Circulating Tumor DNA for Management of Patients With Rectal Cancer: Challenges and Opportunities

ABSTRACT

Recently, organ preservation with total neoadjuvant therapy resulted in substantial progress in the management of locally advanced rectal cancer (LARC). The PROSPECT trial showed noninferiority of de-escalation of radiotherapy for patients with low-risk LARC who do not need abdominoperineal resection. Although these escalation and de-escalation approaches offer more personalized therapeutic approaches, the current state of care for patients with rectal cancer is far from individualized management. Circulating tumor DNA (ctDNA) is known to be one of the most powerful prognostic factors for early relapse and has been investigated in several interventional clinical trials to offer more precise treatment algorithms. In this review article, we discuss recent updates from studies examining the role of ctDNA for the prediction of treatment response and recurrence for patients with rectal cancer. We also elaborate on the future potential use of ctDNA in treatment escalation and de-escalation approaches for more personalized therapeutic interventions.

Circulating tumor DNA in patients with locally advanced rectal cancer treated with multimodal treatment

Background

The management of locally advanced rectal cancer (LARC) relies on a multimodal approach. Neither instrumental work-up nor molecular biomarkers are currently available to identify a risk-adapted strategy.

Objectives

We aim to investigate the role of circulating tumor DNA (ctDNA) and its clearance at different timepoints during chemo-radiotherapy (CRT) and correlate them with clinical outcomes.

Design

Between November 2014 and November 2019, we conducted a monocentric prospective observational study enrolling consecutive patients with LARC managed with neoadjuvant standard CRT (capecitabine and concomitant pelvic long-course radiotherapy), followed by consolidation capecitabine in selected cases and surgery.

Methods

Blood samples for ctDNA were obtained at pre-planned timepoints. We evaluated the correlation of baseline variant allele frequency (VAF) with pathologic complete response (pCR) down-staging, node regression (pN0), event-free survival (EFS), and overall survival (OS).

Results

Among 112 screened patients, 61 were enrolled. In all, 38 (62%) had a positive ctDNA at baseline with VAF > 0 and 23 had negative ctDNA (VAF = 0). Among patients with negative ctDNA, 30% had a complete response, while only 13% of positive ctDNA patients had pCR [odds ratio (OR) 0.35 (95% confidence interval (CI): 0.10-1.26), p = 0.11]. Similarly, 96% and 74% of pN0 were observed among negative and positive ctDNA patients, respectively [OR 0.13 (95% CI: 0.02-1.07), p = 0.058]. The presence of a baseline VAF > 0 was associated with a trend toward a lower EFS compared with VAF = 0 patients [hazard ratio (HR) = 2.30, 95% CI: 0.63-8.36, p = 0.21]. Within the limitations of small sample size, no difference in OS was observed according to the baseline ctDNA status (HR = 1.18, 95% CI: 0.35-4.06, p = 0.79).

Conclusion

Within the limitations of a reduced number of patients, patients with baseline negative ctDNA seem to show a higher probability of pN0 status and a trend toward improved EFS. Prospective translational studies are required to define the role of ctDNA analysis in the multimodal treatment of LARC.

A dynamic nomogram for predicting pathologic complete response to neoadjuvant chemotherapy in locally advanced rectal cancer

AIM

To explore the clinical factors associated with pathologic complete response (pCR) for locally advanced rectal cancer (LARC) patients treated with neoadjuvant chemoradiotherapy (nCRT) and develop a web-based dynamic nomogram.

METHODS

Retrospective analysis of patients with examination confirmed LARC from 2011 to 2022. Patients from the Union Hospital of Fujian Medical University were included as the training cohort (n = 1579) and Zhangzhou Hospital of Fujian Medical University as the external validation cohort (n = 246).

RESULTS

In the training cohort, after nCRT, 350 (22.2%) patients achieved pCR. More stomas were avoided in pCR patients (73.9% vs. 69.7%, p = 0.043). After a median follow-up time of 47.7 months (IQR 2-145) shown OS (5-year: 93.7% vs. 81.0%, HR = 0.310, 95%CI: 0.189-0.510, p < 0.001) and DFS (5-year: 91.2% vs. 75.0%, HR = 0.204, 95%CI: 0.216-0.484, p < 0.001) were significantly better among patients with pCR than non-pCR. Multivariable Logistic analysis shown pCR was significantly associated with Pre-CRT CEA (HR = 0.944, 95%CI: 0.921-0.968; p < 0.001), histopathology (HR = 4.608, 95%CI: 2.625-8.089; p < 0.001), Pre-CRT T stage (HR = 0.793, 95%CI: 0.634-0.993; p = 0.043), Pre-CRT N stage (HR = 0.727, 95%CI: 0.606-0.873; p = 0.001), Pre-CRT MRI EMVI (HR = 0.352, 95%CI: 0.262-0.473; p < 0.001), total neoadjuvant therapy (HR = 2.264, 95%CI: 1.280-4.004; p = 0.005). Meanwhile, the online version of the nomogram established in this study was publicized on an open-access website (URL: https://pcrpredict.shinyapps.io/LARC2/). The model predicted accuracy with a C-index of 0.73 (95% CI: 0.70-0.75), with an average C-index of 0.73 for the internal cross validation and 0.78 (95% CI: 0.72-0.83) for the external validation cohort, showing excellent model accuracy. Delong test results showed the model has an important gain value for clinical characteristics to predict pCR in rectal cancer.

CONCLUSIONS

Patients with pCR had a better prognosis, including OS and DFS, and were independently associated with Pre-CRT CEA, histopathology, Pre-CRT T/N stage, Pre-CRT MRI EMVI, and TNT. A web-based dynamic nomogram was successfully established for clinical use at any time.

Assessing circulating tumour DNA (ctDNA) as a prognostic biomarker in locally advanced rectal cancer: a systematic review and meta-analysis

INTRODUCTION

Circulating tumour DNA (ctDNA) has emerged as a promising biomarker in various cancer types, including locally advanced rectal cancer (LARC), offering potential insights into disease progression, treatment response and recurrence. This review aims to comprehensively evaluate the utility of ctDNA as a prognostic biomarker in LARC.

METHODS

PubMed, EMBASE and Web of Science were searched as part of our review. Studies investigating the utility of ctDNA in locally advanced rectal cancer (LARC) were assessed for eligibility. Quality assessment of included studies was performed using the Newcastle Ottawa Scale (NOS) risk of bias tool. Outcomes extracted included basic participant characteristics, ctDNA details and survival data. A meta-analysis was performed on eligible studies to determine pooled recurrence-free survival (RFS).

RESULTS

Twenty-two studies involving 1676 participants were included in our analysis. Methodological quality categorised by the Newcastle Ottawa Scale was generally satisfactory across included studies. ctDNA detected at various time intervals was generally associated with poor outcomes across included studies. Meta-analysis demonstrated a pooled hazard ratio of 8.87 (95% CI 4.91-16.03) and 15.15 (95% CI 8.21-27.95), indicating an increased risk of recurrence with ctDNA positivity in the post-neoadjuvant and post-operative periods respectively.

CONCLUSION

Our systematic review provides evidence supporting the prognostic utility of ctDNA in patients with LARC, particularly in identifying patients at higher risk of disease recurrence in the post-neoadjuvant and post-operative periods.

PTEN and P-4E-BP1 might be associated with postoperative recurrence of rectal cancer patients undergoing concurrent radiochemotherapy

BACKGROUND

Local recurrence after surgery and radiochemotherapy seriously affects the prognosis of locally advanced rectal cancer (LARC) patients. Studies on molecular markers related to the radiochemotherapy sensitivity of cancers have been widely carried out, which might provide valued information for clinicians to carry out individual treatment.

AIM

To find potential biomarkers of tumors for predicting postoperative recurrence.

METHODS

In this study, LARC patients undergoing surgery and concurrent radiochemotherapy were enrolled. We focused on clinicopathological factors and PTEN, SIRT1, p-4E-BP1, and pS6 protein expression assessed by immunohistochemistry in 73 rectal cancer patients with local recurrence and 76 patients without local recurrence.

RESULTS

The expression of PTEN was higher, while the expression of p-4E-BP1 was lower in patients without local recurrence than in patients with local recurrence. Moreover, TNM stage, lymphatic vessel invasion (LVI), PTEN and p-4E-BP1 might be independent risk factors for local recurrence after LARC surgery combined with concurrent radiochemotherapy.

CONCLUSIONS

This study suggests that PTEN and p-4E-BP1 might be potential biomarkers for prognostic prediction and therapeutic targets for LARC.

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.

Personalized circulating tumor DNA monitoring improves recurrence surveillance and management after curative resection of colorectal liver metastases: a prospective cohort study

BACKGROUND

Approximately 60% of patients with colorectal liver metastases (CRLM) experience relapse within 2 years after radical resection, previous studies have proven that repeat local treatment (LT) could prolong survival, however, it is difficult to seize the window for LT due to the lack of a high-sensitive surveillance method. In this study, the authors aim to examine the value of longitudinal circulating tumor DNA (ctDNA) in guiding adjuvant chemotherapy, optimizing clinical surveillance strategy, and thereby improving CRLM outcomes.

MATERIALS AND METHODS

The authors conducted a prospective clinical trial using a personalized, tumor-informed ctDNA assay to monitor 60 CRLM patients undergoing resection with curative intent. Formalin-fixed paraffin-embedded tumor samples were collected after surgery. Blood samples were collected before surgery, 30 days after surgery (post-OP), and every third month until relapse or up to 2 years.

RESULTS

A total of 394 plasma samples from 60 eligible patients were analyzed, with a median follow-up time of 31.3 months. Landmark analyses revealed that detectable ctDNA at post-OP (HR, 4.8), postadjuvant chemotherapy (HR, 6.0), and end-of-treatment (HR, 5.6) were associated with higher recurrence risk ( P <0.001). Post-OP ctDNA positivity served as the only independent prognostic marker in the multivariant analysis (HR, 5.1; P <0.001). Longitudinal ctDNA analysis identified relapsed patients at both sensitivity and specificity of 100%. Most (75%) patients were found with radiological relapse within 6 months after the first detectable ctDNA with a median lead time of 3.5 months. In relapsed patients, 73.2% had oligometastatic disease and 61% were liver-restricted, of which 72.0% received repeat LTs, and 60.0% achieved a secondary no evidence of disease status.

CONCLUSIONS

Longitudinal ctDNA monitoring assists in early prediction of relapse, and thereby improves survival of CRLM patients by increased secondary resection rate and secondary no evidence of disease rate.

Multi-Institutional Study Evaluating the Role of Circulating Tumor DNA in the Management of Appendiceal Cancers

PURPOSE

Conventional surveillance methods are poorly sensitive for monitoring appendiceal cancers (AC). This study investigated the utility of circulating tumor DNA (ctDNA) in evaluating systemic therapy response and recurrence after surgery for AC.

METHODS

Patients from two specialized centers who underwent tumor-informed ctDNA testing (Signatera) were evaluated to determine the association between systemic therapy and ctDNA detection. In addition, the accuracy of ctDNA detection during surveillance for the diagnosis of recurrence after complete cytoreductive surgery (CRS) for grade 2-3 ACs with peritoneal metastases (PM) was investigated.

RESULTS

In this cohort of 94 patients with AC, most had grade 2-3 tumors (84.0%) and PM (84.0%). Fifty patients completed the assay in the presence of identifiable disease, among which ctDNA was detected in 4 of 7 (57.1%), 10 of 16 (62.5%), and 19 of 27 (70.4%) patients with grade 1, 2, and 3 diseases, respectively. Patients who had recently received systemic chemotherapy had ctDNA detected less frequently (7 of 16 [43.8%] v 26 of 34 [76.5%]; odds ratio, 0.22 [95% CI, 0.06 to 0.82]; P = .02). Among 36 patients with complete CRS for grade 2-3 AC-PM, 16 (44.4%) developed recurrence (median follow-up, 19.6 months). ctDNA detection was associated with shorter recurrence-free survival (median 11.3 months v not reached; hazard ratio, 14.1 [95% CI, 1.7 to 113.8]; P = .01) and showed high accuracy for the detection of recurrence (sensitivity 93.8%, specificity 85.0%). ctDNA was more sensitive than carcinoembryonic antigen (62.5%), CA19-9 (25.0%), and CA125 (18.8%) and was the only elevated biomarker in four (25%) patients with recurrence.

CONCLUSION

This study revealed a reduced ctDNA detection frequency after systemic therapy and accurate recurrence assessment after CRS. These findings underscore the role of ctDNA as a predictive and prognostic biomarker for grade 2-3 AC-PM management.

Circulating tumour DNA-Based molecular residual disease detection in resectable cancers: a systematic review and meta-analysis

BACKGROUND

Circulating tumour DNA (ctDNA)-based molecular residual disease (MRD) detection technology has been widely used for recurrence evaluation, but there is no agreement on the efficacy of assessing recurrence and overall survival (OS) prognosis, as well as the sensitivity and specificity of landmark detection and longitudinal detection.

METHODS

We systematically searched Pubmed, Embase, Cochrane, and Scopus for prospective studies or randomized controlled trials that collected blood samples prospectively. The search period was from Jan 1, 2013, to Sept 10, 2023. We excluded retrospective studies. The primary endpoint was to assess the hazard ratio (HR) between circulating tumour DNA positive (ctDNA+) and negative (ctDNA-) for recurrence-free survival incidence (RFS), disease-free survival (DFS), progression-free survival (PFS), event-free survival (EFS), time to recurrence (TTR), distant metastasis-free survival (DMFS) or OS in patients with resectable cancers. We calculated the pooled HR of recurrence and OS and 95% confidence interval (CI) in patients with resected cancers using a random-effects model. Pooled sensitivity and specificity were estimated using the bivariate random effects model.

FINDINGS

This systematic review and meta-analysis returned 7578 records, yielding 80 included studies after exclusion. We found that the HR of recurrence across all included cancers between patients with ctDNA+ and ctDNA- was 7.48 (95% CI 6.39-8.77), and the OS was 5.58 (95% CI 4.17-7.48). We also found that the sensitivity, area under the summary receiver operating characteristic curve (AUSROC) and diagnostic odds ratio (DOR) of longitudinal tests were higher than that of landmark tests between patients with ctDNA+ and ctDNA- (0.74, 95% CI 0.68-0.80 vs 0.50, 95% CI 0.46-0.55; 0.88 vs. 0.80; 25.70, 95% CI 13.20-45.40 vs. 9.90, 95% CI 7.77-12.40).

INTERPRETATION

Postoperative ctDNA testing was a significant prognosis factor for recurrence and OS in patients with resectable cancers. However, the overall sensitivity of ctDNA-MRD detection could be better. Longitudinal monitoring can improve the sensitivity, AUSROC, and DOR.

FUNDING

Special fund project for clinical research of Qingyuan People's Hospital (QYRYCRC2023006), plan on enhancing scientific research in GMU (GZMU-SH-301).

Noninvasive Blood-Based Cancer Detection in Veterinary Medicine

The past decade has seen incredible advances in blood-based cancer detection in people and in dogs - yet this represents only a glimpse of the benefits these tests can provide to patients. The clinical uses of this technology range from screening asymptomatic individuals for early detection to use as an aid in diagnosis when cancer is suspected, to cancer monitoring both during and after treatment. This article summarizes the benefits of early cancer detection and examines use cases and methods of blood-based cancer detection in dogs, including quantitative, qualitative, and alternative approaches.

ALLIANCE A022104/NRG-GI010: The Janus Rectal Cancer Trial: a randomized phase II/III trial testing the efficacy of triplet versus doublet chemotherapy regarding clinical complete response and disease-free survival in patients with locally advanced rectal cancer

Background

Recent data have demonstrated that in locally advanced rectal cancer (LARC), a total neoadjuvant therapy (TNT) approach improves compliance with chemotherapy and increases rates of tumor response compared to neoadjuvant chemoradiation (CRT) alone. They further indicate that the optimal sequencing of TNT involves consolidation (rather than induction) chemotherapy to optimize complete response rates. Data, largely from retrospective studies, have also shown that patients with clinical complete response (cCR) after neoadjuvant therapy may be managed safely with the watch and wait approach (WW) instead of preemptive total mesorectal resection (TME). However, the optimal consolidation chemotherapy regimen to achieve cCR has not been established, and a randomized clinical trial has not robustly evaluated cCR as a primary endpoint. Collaborating with a multidisciplinary oncology team and patient groups, we designed this NCI-sponsored study of chemotherapy intensification to address these issues and to drive up cCR rates, to provide opportunity for organ preservation, improve quality of life for patients and improve survival outcomes.

Methods

In this NCI-sponsored multi-group randomized, seamless phase II/III trial (1:1), up to 760 patients with LARC, T4N0, any T with node positive disease (any T, N+) or T3N0 requiring abdominoperineal resection or coloanal anastomosis and distal margin within 12 cm of anal verge will be enrolled. Stratification factors include tumor stage (T4 vs T1-3), nodal stage (N+ vs N0) and distance from anal verge (0-4; 4-8; 8-12 cm). Patients will be randomized to receive neoadjuvant long course chemoradiation (LCRT) followed by consolidation doublet (mFOLFOX6 or CAPOX) or triplet chemotherapy (mFOLFIRINOX) for 3-4 months. LCRT in both arms involves 4500 cGy in 25 fractions over 5 weeks + 900 cGy boost in 5 fractions with a fluoropyrimidine (capecitabine preferred). Patients will undergo assessment 8-12 (+/- 4) weeks post-TNT completion. The primary endpoint for the phase II portion will compare cCR between treatment arms. A total number of 296 evaluable patients (148 per arm) will provide statistical power of 90.5% to detect an 17% increase in cCR rate, at a one-sided alpha=0.048. The primary endpoint for the phase III portion will compare disease-free survival (DFS) between treatment arms. A total of 285 DFS events will provide 85% power to detect an effect size of hazard ratio 0.70 at a one-sided alpha of 0.025, requiring enrollment of 760 patients (380 per arm). Secondary objectives include time-to event outcomes (overall survival, organ preservation time and time to distant metastasis) and adverse effects. Biospecimens including archival tumor tissue, plasma and buffy coat in EDTA tubes, and serial rectal MRIs will be collected for exploratory correlative research. This study, activated in late 2022, is open across the NCTN and has a current accrual of 312. Support: U10CA180821, U10CA180882, U24 CA196171; https://acknowledgments.alliancefound.org .

Discussion

Building off of data from modern day rectal cancer trials and patient input from national advocacy groups, we have designed the current trial studying chemotherapy intensification via a consolidation chemotherapy approach with the intent to enhance cCR and DFS rates, increase organ preservation rates, and improve quality of life for patients with rectal cancer.

Trial Registration

Clinicaltrials.gov ID: NCT05610163 ; Support includes U10CA180868 (NRG) and U10CA180888 (SWOG).

Advancing Personalized Medicine in the Treatment of Locally Advanced Rectal Cancer

Rectal cancer presents a significant burden globally, often requiring multimodal therapy for locally advanced cases. Long-course chemoradiotherapy (LCRT) and short-course radiotherapy (SCRT) followed by surgery have been conventional neoadjuvant approaches. Recent trials favor LCRT due to improved local control. However, distant tumor recurrence remains a concern, prompting the exploration of total neoadjuvant therapy (TNT) as a comprehensive treatment strategy. Immune checkpoint inhibitors (ICIs) show promise, particularly in mismatch repair-deficient (dMMR) or microsatellite instability-high (MSI-H) tumors, potentially revolutionizing neoadjuvant regimens. Nonoperative management (NOM) represents a viable alternative post-neoadjuvant therapy for selected patients achieving complete clinical response (cCR). Additionally, monitoring minimal residual disease (MRD) using circulating tumor DNA (ctDNA) emerges as a non-invasive method for the assessment of treatment response. This review synthesizes current evidence on TNT, ICIs, NOM, and ctDNA, elucidating their implications for rectal cancer management and highlighting avenues for future research and clinical application.

Partial response to crizotinib + regorafenib + PD-1 inhibitor in a metastatic BRAF V600EMT colon cancer patient with acquired C-MET amplification and TPM4-ALK fusion: a case report

Background

Colorectal cancer (CRC) with the Raf murine sarcoma viral oncogene homolog B (BRAF) V600E had a relatively poor prognosis. Anaplastic lymphoma kinase (ALK) fusion and the mesenchymal-to-epithelial transition factor (MET) amplification have been recognized as potentially important therapeutic targets in non-small cell lung cancer (NSCLC). However, both of them are of extremely lower frequencies (<2%) in metastatic CRC, and few studies have mentioned the real application of their inhibitors in CRC treatment.

Case Description

A 49-year-old Chinese male was diagnosed with ascending colon adenocarcinoma (cT3N+?M1) with liver metastases. The patient performed next-generation sequencing (NGS) using tissue and circulating tumor DNA (ctDNA), and the results showed a BRAF V600E mutation. He received an initial combination treatment with cetuximab, dabrafenib, and trametinib with a partial response (PR) assessment. We changed the therapy regimen on this patient several times because of the patient's intolerance to the drugs or the inefficacy of the treatment. During this period, we detected the c-MET amplification and tropomyosin 4 (TPM4)-ALK fusion by NGS after triplet targeted therapy (tislelizumab, dabrafenib, and trametinib), thus he was finally treated with programmed cell death protein 1 (PD-1) inhibitor (tislelizumab), MET/ALK inhibitor (crizotinib) plus multikinase inhibitor (regorafenib). Imageological examinations showed that PR was achieved and ctDNA sequencing results indicated a significantly reduced BRAF mutation frequency, MET amplification and TPM4-ALK fusion were undetectable. NGS analysis of peripheral blood showed a recurrence of the MET acquired resistant amplification mutation over 2 months of ongoing treatment. but the patient was assessed as PR and still under treatment of crizotinib, tislelizumab and regorafenib within good physical condition. At the last follow-up on October 2021, the patient died of symptomatic treatment fail for obstructive jaundice. The patient finally achieved 11 months overall survival.

Conclusions

This study reported a co-existence of a BRAF V600E mutation, c-MET amplification and TPM4-ALK fusion in a CRC patient. Administration of crizotinib combined with regorafenib and tislelizumab obtained an obvious response. Furthermore, continuous ctDNA detection appears to be a promising technique to monitor tumor burden, which may provide better clinical decision support during the disease course.

Role of Circulating Tumor DNA Among Patients with Colorectal Peritoneal Metastases

PURPOSE

This was a review of circulating tumor DNA (ctDNA) in patients with peritoneal metastases from colorectal cancer.

METHODS

We searched the PubMed database for studies reporting detection of ctDNA in patients with colorectal cancer (CRC) and with peritoneal metastases (PM) from colorectal cancer (CRPM). We extracted data on the population included, number of subjects, study design, type of ctDNA assay used and schedule, and the major findings from these publications.

RESULTS

We identified 13 studies for review investigating ctDNA, using a variety of ctDNA assays, among 1787 patients with CRC without PM, as well as four eligible published and one unpublished (in press) studies, which included 255 patients with PM from any primary site and 61 patients with CRPM. Among the 13 studies investigating ctDNA among CRC without PM, posttreatment surveillance ctDNA was associated with recurrence and was generally more sensitive than imaging or tumor markers. Among the five studies including patients with PM, ctDNA was not universally able to detect the presence of PM, but when present, ctDNA predicted worse outcomes.

CONCLUSION

Circulating-tumor DNA is a potentially useful surveillance tool for patients with CRC. However, the sensitivity of ctDNA to detect CRPM is variable and warrants further inquiry.

ctDNA-based minimal residual disease detection in lung cancer patients treated with curative intended chemoradiotherapy using a clinically transferable approach

BACKGROUND

Reliable biomarkers are needed to identify tumor recurrence of non-small cell lung cancer (NSCLC) patients after chemoradiotherapy (CRT) with curative intent. This could improve consolidation therapy of progressing patients. However, the approach of existing studies has limited transferability to the clinic.

MATERIALS AND METHODS

A retrospective analysis of 135 plasma samples from 56 inoperable NSCLC patients who received CRT with curative intent was performed. Plasma samples collected at baseline, at the first check-up (average 1.6 months post-RT), and at the second check-up (average 4.5 months post-RT) were analyzed by deep sequencing with a commercially available cancer personalized profiling strategy (CAPP-Seq) using a tumor-agnostic approach.

RESULTS

Detection of circulating tumor DNA (ctDNA) at 4.5 months after therapy was significantly associated with higher odds of tumor recurrence (OR: 5.4 (CI: 1.1-31), Fisher's exact test: p-value = 0.022), and shorter recurrence-free survival (RFS) (HR: 4.1 (CI: 1.7-10); log-rank test: p-value = 9e-04). In contrast, detection of ctDNA at 1.6 months after therapy was not associated with higher odds of tumor recurrence (OR: 2.7 (CI: 0.67-12), Fisher's exact test: p-value = 0.13) or shorter RFS (HR: 1.5 (CI: 0.67-3.3); log-rank test: p-value = 0.32).

CONCLUSION

This study demonstrates that the detection of ctDNA can be used to identify minimal residual disease 4.5 months after CRT in NSCLC patients using a commercially available kit and a tumor-agnostic approach. Furthermore, the time point of collecting the plasma sample after CRT has decisive importance for the prognostic value of ctDNA.

MICRO ABSTRACT

This study analysed 135 plasma samples from 56 NSCLC patients treated with curative intent chemoradiotherapy using a tumor-agnostic approach. Detecting ctDNA at 4.5 months post-treatment was linked to higher recurrence odds, indicating ctDNA's potential as a biomarker for identifying residual disease after treatment with curative intent. Importantly, the study emphasizes the importance of timing for accurate ctDNA analysis results.

A Practical Approach to Interpreting Circulating Tumor DNA in the Management of Gastrointestinal Cancers

BACKGROUND

There is accumulating evidence supporting the clinical use of circulating tumor DNA (ctDNA) in solid tumors, especially in different types of gastrointestinal cancer. As such, appraisal of the current and potential clinical utility of ctDNA is needed to guide clinicians in decision-making to facilitate its general applicability.

CONTENT

In this review, we firstly discuss considerations surrounding specimen collection, processing, storage, and analysis, which affect reporting and interpretation of results. Secondly, we evaluate a selection of studies on colorectal, esophago-gastric, and pancreatic cancer to determine the level of evidence for the use of ctDNA in disease screening, detection of molecular residual disease (MRD) and disease recurrence during surveillance, assessment of therapy response, and guiding targeted therapy. Lastly, we highlight current limitations in the clinical utility of ctDNA and future directions.

SUMMARY

Current evidence of ctDNA in gastrointestinal cancer is promising but varies depending on its specific clinical role and cancer type. Larger prospective trials are needed to validate different aspects of ctDNA clinical utility, and standardization of collection protocols, analytical assays, and reporting guidelines should be considered to facilitate its wider applicability.