Circulating Tumor DNA Analysis Guiding Adjuvant Therapy in Stage II Colon Cancer

[What is confirmed in the treatment of colon cancer?]

Colorectal cancer is the second most common cancer diagnosed in Germany and is the third most frequent cause of cancer-related death in both males and females. The majority of colorectal cancers occur via the adenoma-carcinoma sequence of origin. This means that colorectal cancers can be endoscopically detected in premalignant stages and can be curatively treated within the framework of early detection. Screening colonoscopy and, to a lesser extent, fecal occult blood testing, have led to a reduction in the colon cancer-related incidence and mortality. The acceptance and the use of screening colonoscopy should therefore be developed further. Treatment strategies for colorectal cancer are based on TNM staging, supplemented by anatomical and histopathological risk features as well as individual patient characteristics and treatment preferences. The molecular tumor profile is increasingly used to complement decision-making in the surgical, adjuvant and palliative treatment of colorectal cancer. Colon and rectal cancer have many similarities; however, they differ in the preoperative, surgical and adjuvant treatment strategies. This article focuses on colon cancer.

Practical Considerations for the Use of Circulating Tumor DNA in the Treatment of Patients With Cancer: A Narrative Review

Importance

Personalized medicine based on tumor profiling and identification of actionable genomic alterations is pivotal in cancer management. Although tissue biopsy is still preferred for diagnosis, liquid biopsy of blood-based tumor analytes, such as circulating tumor DNA, is a rapidly emerging technology for tumor profiling.

Observations

This review presents a practical overview for clinicians and allied health care professionals for selection of the most appropriate liquid biopsy assay, specifically focusing on circulating tumor DNA and how it may affect patient treatment and case management across multiple tumor types. Multiple factors influence the analytical validity, clinical validity, and clinical utility of testing. This review provides recommendations and practical guidance for best practice. Current methodologies include polymerase chain reaction-based approaches and those that use next-generation sequencing (eg, capture-based profiling, whole exome, or genome sequencing). Factors that may influence utility include sensitivity and specificity, quantity of circulating tumor DNA, detection of a small vs a large panel of genes, and clonal hematopoiesis of indeterminate potential. Currently, liquid biopsy appears useful in patients unable to undergo biopsy or where mutations detected may be more representative of the predominant tumor burden than for tissue-based assays. Other potential applications may include screening, primary diagnosis, residual disease, local recurrence, therapy selection, or early therapy response and resistance monitoring.

Conclusions and Relevance

This review found that liquid biopsy is increasingly being used clinically in advanced lung cancer, and ongoing research is identifying applications of circulating tumor DNA-based testing that complement tissue analysis across a broad range of clinical settings. Circulating tumor DNA technologies are advancing quickly and are demonstrating potential benefits for patients, health care practitioners, health care systems, and researchers, at many stages of the patient oncologic journey.

Tumour break load is a biologically relevant feature of genomic instability with prognostic value in colorectal cancer

BACKGROUND

Clinically implemented prognostic biomarkers are lacking for the 80% of colorectal cancers (CRCs) that exhibit chromosomal instability (CIN). CIN is characterised by chromosome segregation errors and double-strand break repair defects that lead to somatic copy number aberrations (SCNAs) and chromosomal rearrangement-associated structural variants (SVs), respectively. We hypothesise that the number of SVs is a distinct feature of genomic instability and defined a new measure to quantify SVs: the tumour break load (TBL). The present study aimed to characterise the biological impact and clinical relevance of TBL in CRC.

METHODS

Disease-free survival and SCNA data were obtained from The Cancer Genome Atlas and two independent CRC studies. TBL was defined as the sum of SCNA-associated SVs. RNA gene expression data of microsatellite stable (MSS) CRC samples were used to train an RNA-based TBL classifier. Dichotomised DNA-based TBL data were used for survival analysis.

RESULTS

TBL shows large variation in CRC with poor correlation to tumour mutational burden and fraction of genome altered. TBL impact on tumour biology was illustrated by the high accuracy of classifying cancers in TBL-high and TBL-low (area under the receiver operating characteristic curve [AUC]: 0.88; p < 0.01). High TBL was associated with disease recurrence in 85 stages II-III MSS CRCs from The Cancer Genome Atlas (hazard ratio [HR]: 6.1; p = 0.007) and in two independent validation series of 57 untreated stages II-III (HR: 4.1; p = 0.012) and 74 untreated stage II MSS CRCs (HR: 2.4; p = 0.01).

CONCLUSION

TBL is a prognostic biomarker in patients with non-metastatic MSS CRC with great potential to be implemented in routine molecular diagnostics.

The ctDNA-based postoperative molecular residual disease status in different subtypes of early-stage breast cancer

Background

Breast cancer is a highly heterogeneous disease. Early-stage, non-metastatic breast cancer is considered curable after definitive treatment. Early detection of tumor recurrence and metastasis through sensitive biomarkers is helpful for guiding clinical decision-making and early intervention in second-line treatment, which could improve patient prognosis and survival.

Methods

In this real-world study, we retrospectively analyzed 82 patients with stages I to III breast cancer who had been analyzed by molecular residual disease (MRD) assay. A total of 82 tumor tissues and 224 peripheral blood samples were collected and detected by next-generation sequencing (NGS) based on a 1,021-gene panel in this study.

Results

MRD positivity was detected in 18 of 82 patients (22.0%). The hormone receptor-/human epidermal growth factor receptor 2+ (HR-/HER2+) subgroup had the highest postoperative MRD detection rate at 30.8% (4/13). The BRCA2 and SLX4 genes were significantly enriched in all patients in the MRD positive group and FGFR1 amplification was significantly enriched in the MRD negative group with HR+/HER2-. The number of single nucleotide variants (SNVs) in tissue samples of MRD-positive patients was higher than that of MRD-negative patients (11.94 vs. 8.50 SNVs/sample). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that there was a similar biological function of the tumor-mutated genes in the 2 MRD status groups.

Conclusions

This real-world study confirmed that patient samples of primary tumor tissue with different MRD status and molecular subtypes had differential genetic features, which may be used to predict patients at high risk for recurrence.

Role of ctDNA for the detection of minimal residual disease in resected non-small cell lung cancer: a systematic review

Background

Operable stage I-III non-small cell lung cancer (NSCLC) has a high risk of recurrence, mainly due to remnant clones of the disease defined as minimal residual disease (MRD). Adjuvant chemotherapy has a limited efficacy in reducing the risk of relapse, and prognostic as well as predictive biomarkers in this context are currently missing.

Methods

We performed a systematic review to evaluate the state of the art about the role of circulating tumor DNA detection through liquid biopsy for the assessment of MRD in resected early-stage NSCLC patients.

Results

Among the 650 studies identified, 13 were eligible and included. Although highly heterogeneous, all the studies demonstrated a poor prognosis in patients with post-operative MRD, with a detection rate ranging from 6% to 45%. MRD detection preceded radiographic/clinical recurrence by a mean of 5.5 months. MRD positive patients were most likely to benefit from adjuvant treatment in terms of recurrence-free survival (RFS). Consistently, adjuvant therapy did not minimize the risk of relapse in the MRD negative group.

Conclusions

Liquid biopsy has a relevant role in assessing post-surgical MRD in resected NSCLC. Since currently there are no criteria other than stage and risk factors for the choice of adjuvant treatment in this setting, post-operative assessment of MRD through liquid biopsy might be a promising approach to guide the decision.

Epithelial to Mesenchymal Transition as Mechanism of Progression of Pancreatic Cancer: From Mice to Men

Owed to its aggressive yet subtle nature, pancreatic cancer remains unnoticed till an advanced stage so that in most cases the diagnosis is made when the cancer has already spread to other organs with deadly efficiency. The progression from primary tumor to metastasis involves an intricate cascade of events comprising the pleiotropic process of epithelial to mesenchymal transition (EMT) facilitating cancer spread. The elucidation of this pivotal phenotypic change in cancer cell morphology, initially heretic, moved from basic studies dissecting the progression of pancreatic cancer in animal models to move towards human disease, although no clinical translation of the concept emerged yet. Despite this transition, a full-blown mesenchymal phenotype may not be accomplished; rather, the plasticity of the program and its dependency on heterotopic signals implies a series of fluctuating modifications of cancer cells encompassing mesenchymal and epithelial features. Despite the evidence supporting the activation of EMT and MET during cancer progression, our understanding of the relationship between tumor microenvironment and EMT is not yet mature for a clinical application. In this review, we attempt to resume the knowledge on EMT and pancreatic cancer, aiming to include the EMT among the hallmarks of cancer that could potentially modify our clinical thinking with the purpose of filling the gap between the results pursued in basic research by animal models and those achieved in translational research by surrogate biomarkers, as well as their application for prognostic and predictive purposes.

Biomarkers in the management of lung cancer: changing the practice of thoracic oncology

Lung cancer currently represents a leading cause of cancer death. Substantial progress achieved in the medical therapy of lung cancer during the last decade has been associated with the advent of targeted therapy, including immunotherapy. The targeted therapy has gradually shifted from drugs suppressing general mechanisms of tumor growth and progression to agents aiming at transforming mechanisms like driver mutations in a particular tumor. Knowledge of the molecular characteristics of a tumor has become an essential component of the more targeted therapeutic approach. There are specific challenges for biomarker determination in lung cancer, in particular a commonly limited size of tumor sample. Liquid biopsy is therefore of particular importance in the management of lung cancer. Laboratory medicine is an indispensable part of multidisciplinary management of lung cancer. Clinical Chemistry and Laboratory Medicine (CCLM) has played and will continue playing a major role in updating and spreading the knowledge in the field.

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

Circulating tumor DNA (ctDNA) is reported to be promising in localized colorectal cancer (CRC). The present study aimed to retrospectively evaluate the impact of ctDNA in patients with a resected stage II CRC from the PROGIGE 13 trial with available paired tumor and blood samples. A group of recurrent patients were matched one-to-one with nonrecurrent patients according to sex, tumor location, treatment sequence, and blood collection timing. CtDNA was analyzed by digital PCR according to NGS of tumors. Disease-free survival (DFS) and overall survival (OS) were analyzed based on ctDNA, and the risks of recurrence and death were determined. A total of 134 patients were included, with 67 patients in each group. At least one alteration was identified in 115/134 tumors. Postoperative ctDNA was detected in 10/111 (9.0%) informative samples and was detected more frequently in the recurrent group (16.7% versus 1.8%; p = 0.02). The median DFS of ctDNA+ versus ctDNA- patients was 16.8 versus 54 months (p = 0.002), respectively, and the median OS was 51.3 versus 69.5 months (p = 0.03), respectively. CtDNA was associated with recurrence (ORa = 11.13, p = 0.03) and death (HRa = 3.15, p = 0.01). In conclusion, the presence of postoperative ctDNA is associated with both recurrence and survival in stage II CRC.

Molecular testing to deliver personalized chemotherapy recommendations: risking over and undertreatment

BACKGROUND

In the adjuvant setting of cancer treatment, de-escalation strategies have the goal of omitting or minimizing treatment in patients, without compromising outcomes. Historically, eligibility for adjuvant treatment solely relied on the patient's clinical and tumor's pathological characteristics. At the turn of the century, based on new biological understanding, molecular-based strategies were tested and sometimes implemented.

MAIN BODY

However, we illustrate how molecularly based de-escalation strategies may paradoxically lead to overtreatment. This may happen when the novel approach is tested in lieu of standard management and may not yield the same results when being implemented in addition to usual practice. In the DYNAMIC trial, adjuvant chemotherapy decision in stage II colon cancer was compared between a circulating tumor DNA (ctDNA)-based approach and the standard care. We show this may result in more patients receiving oxaliplatin-based chemotherapy and may expose a similar proportion of patients to chemotherapy if the novel strategy is implemented in addition to usual practice. The other potential risk is undertreatment. We provide an illustration of early breast cancer, where the decision of adjuvant chemotherapy based on the gene expression signature MammaPrint may lead to inferior outcomes as compared with the clinico-pathologic strategy. This may also happen when non-inferiority designs have large margins. Among solutions, it should be acknowledged that clinico-pathological features, like T4 in colon cancer, may not be abandoned and replaced by novel strategies in real-life practice. Therefore, novel strategies should be tested in addition to standard of care, and not in lieu of. Second, de-escalation trials should focus on the settings where the standard of care has a widespread agreement. This would avoid the risk of testing non-inferiority against an ineffective therapy, which guarantees successes without providing informative data.

CONCLUSION

Simply because a molecular test is rational does not mean it can improve patient outcomes. Here, we highlight how molecular test-based strategies may result in either overtreatment or undertreatment. In the rapidly evolving field of medicine, where technological advances may be transformative, our piece highlights scientific pitfalls to be aware of when considering running such trials or before implementing novel strategies in daily practice.

Clinical Applications of Liquid Biopsy in Colorectal Cancer Screening: Current Challenges and Future Perspectives

Colorectal cancer (CRC) represents the third most prevalent cancer worldwide and a leading cause of mortality among the population of western countries. However, CRC is frequently a preventable malignancy due to various screening tests being available. While failing to obtain real-time data, current screening methods (either endoscopic or stool-based tests) also require disagreeable preparation protocols and tissue sampling through invasive procedures, rendering adherence to CRC screening programs suboptimal. In this context, the necessity for novel, less invasive biomarkers able to identify and assess cancer at an early stage is evident. Liquid biopsy comes as a promising minimally invasive diagnostic tool, able to provide comprehensive information on tumor heterogeneity and dynamics during carcinogenesis. This review focuses on the potential use of circulating tumor cells (CTCs), circulating nucleic acids (CNAs) and extracellular vesicles as emerging liquid biopsy markers with clinical application in the setting of CRC screening. The review also examines the opportunity to implement liquid biopsy analysis during everyday practice and provides highlights on clinical trials researching blood tests designed for early cancer diagnosis. Additionally, the review explores potential applications of liquid biopsies in the era of immunotherapy.

Clinical applications of circulating tumor-derived DNA in the management of gastrointestinal cancers - current evidence and future directions

Advances in Next Generation Sequencing (NGS) technologies have enabled the accurate detection and quantification of circulating tumor-derived (ct)DNA in most gastrointestinal (GI) cancers. The prognostic and predictive utility of ctDNA in patiets with different stages of colorectal (CRC), gastro-esophageal (GEC) and pancreaticobiliary cancers (PBC) are currently under active investigation. The most mature clinical data to date are derived from studies in the prognostic utility of personalized ctDNA-based NGS assays in the detection of minimal residual disease (MRD) and early recurrence after surgery in CRC and other GI cancers. These findings are being validated in several prospective studies which are designed to test if ctDNA could outperform conventional approaches in guiding adjuvant chemotherapy, and in post-operative surveillance in some GI cancers. Several adaptive studies using ctDNA as a screening platform are also being used to identify patients with actionable genomic alterations for clinical trials of targeted therapies. In the palliative setting, ctDNA monitoring during treatment has shown promise in the detection and tracking of clonal variants associated with acquired resistance to targeted therapies and immune-checkpoint inhibitors (ICI). Moreover, ctDNA may help to guide the therapeutic re-challenge of targeted therapies in patients who have prior exposure to such treatment. This review will examine the most updated research findings on ctDNA as a biomarker in CRC, GEC and PBCs. It aims to provide insights into how the unique strengths of this biomarker could be optimally leveraged in improving the management of these GI cancers.

Minimal residual disease in EGFR-mutant non-small-cell lung cancer

Targeted therapy with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) is an effective treatment for EGFR-mutant non-small-cell lung cancer (NSCLC), however most patients invariably relapse after a period of minimal residual disease (MRD). This mini-review explores the mechanistic pathways leading to tumour dormancy, cellular senescence and epigenetic changes involving YAP/TEAD activation. We describe the various approaches of utilising TKIs in combination with agents to intensify initial depth of response, enhance apoptosis and target senescence-like dormancy. This mini-review will also highlight the potential novel therapies under development targeting MRD to improve outcomes for patients with EGFR-mutant NSCLC.

ctDNA-guided adjuvant chemotherapy for colorectal cancer-ready for prime time?

In stage II colorectal cancer, adjuvant chemotherapy is controversial, and overtreatment is substantial due to suboptimal risk stratification. In a recent New England Journal of Medicine article reporting from a prospective randomized phase II trial, Tie and colleagues demonstrate how ctDNA-guided risk-stratification reduces the use of adjuvant chemotherapy without compromising recurrence risk.

Clinical application of advanced multi-omics tumor profiling: Shaping precision oncology of the future

Next-generation DNA sequencing technology has dramatically advanced clinical oncology through the identification of therapeutic targets and molecular biomarkers, leading to the personalization of cancer treatment with significantly improved outcomes for many common and rare tumor entities. More recent developments in advanced tumor profiling now enable dissection of tumor molecular architecture and the functional phenotype at cellular and subcellular resolution. Clinical translation of high-resolution tumor profiling and integration of multi-omics data into precision treatment, however, pose significant challenges at the level of prospective validation and clinical implementation. In this review, we summarize the latest advances in multi-omics tumor profiling, focusing on spatial genomics and chromatin organization, spatial transcriptomics and proteomics, liquid biopsy, and ex vivo modeling of drug response. We analyze the current stages of translational validation of these technologies and discuss future perspectives for their integration into precision treatment.

Accelerating the Development and Validation of Liquid Biopsy for Early Cancer Screening and Treatment Tailoring

Liquid biopsy (LB) is a minimally invasive method which aims to detect circulating tumor-derived components in body fluids. It provides an alternative to current cancer screening methods that use tissue biopsies for the confirmation of diagnosis. This paper attempts to determine how far the regulatory, policy, and governance framework provide support to LB implementation into healthcare systems and how the situation can be improved. For that reason, the European Alliance for Personalised Medicine (EAPM) organized series of expert panels including different key stakeholders to identify different steps, challenges, and opportunities that need to be taken to effectively implement LB technology at the country level across Europe. To accomplish a change of patient care with an LB approach, it is required to establish collaboration between multiple stakeholders, including payers, policymakers, the medical and scientific community, and patient organizations, both at the national and international level. Regulators, pharma companies, and payers could have a major impact in their own domain. Linking national efforts to EU efforts and vice versa could help in implementation of LB across Europe, while patients, scientists, physicians, and kit manufacturers can generate a pull by undertaking more research into biomarkers.

Liquid Biopsies in Colorectal Liver Metastases: Towards the Era of Precision Oncologic Surgery

Tumor mutational analysis has been incorporated into the management of patients with CRLM since it can provide valuable prognostic information as well as guide peri-operative systemic treatment. Unlike tumor biopsy, liquid biopsy has emerged as a promising, non-invasive alternative that can detect cell-derived markers from a variety of body fluids and might better characterize all subclones present at a specific time point and allow sequential monitoring of disease evolution. Although not currently considered standard of care, an increasing number of cancer centers are nowadays routinely using liquid biopsies in the treatment of CRLM patients with promising results. The current review provides an overview of liquid biopsies in cancer therapeutics and focuses on the application of this relatively new approach on patients with CRLM.

The DKTK EXLIQUID consortium – exploiting liquid biopsies to advance cancer precision medicine for molecular tumor board patients

Testing for genetic alterations in tumor tissue allows clinicians to identify patients who most likely will benefit from molecular targeted treatment. EXLIQUID – exploiting liquid biopsies to advance cancer precision medicine – investigates the potential of additional non-invasive tools for guiding therapy decisions and monitoring of advanced cancer patients. The term “liquid biopsy” (LB) refers to non-invasive analysis of tumor-derived circulating material such as cell-free DNA in blood samples from cancer patients. Although recent technological advances allow sensitive and specific detection of LB biomarkers, only few LB assays have entered clinical routine to date. EXLIQUID is a German Cancer Consortium (DKTK)-wide joint funding project that aims at establishing LBs as a minimally-invasive tool to analyze molecular changes in circulating tumor DNA (ctDNA). Here, we present the structure, clinical aim, and methodical approach of the new DKTK EXLIQUID consortium. Within EXLIQUID, we will set up a multicenter repository of high-quality LB samples from patients participating in DKTK MASTER and local molecular tumor boards, which use molecular profiles of tumor tissues to guide targeted therapies. We will develop LB assays for monitoring of therapy efficacy by the analysis of tumor mutant variants and tumor-specific DNA methylation patterns in ctDNA from these patients. By bringing together LB experts from all DKTK partner sites and exploiting the diversity of their particular expertise, complementary skills and technologies, the EXLIQUID consortium addresses the challenges of translating LBs into the clinic. The DKTK structure provides EXLIQUID a unique position for the identification of liquid biomarkers even in less common tumor types, thereby extending the group of patients benefitting from non-invasive LB testing. Besides its scientific aims, EXLIQUID is building a valuable precision oncology cohort and LB platform which will be available for future collaborative research studies within the DKTK and beyond.

Leveraging Comprehensive Cancer Registry Data to Enable a Broad Range of Research, Audit and Patient Support Activities

Simple Summary

Registry data has the potential to support a broad range of research, audit and education initiatives. Here, we describe the experience and learnings of a series of large multi-institutional cancer registries that leverage real-world clinical data for a range of purposes, that informs the conduct and output of each registry in a virtuous cycle. Lessons learnt include the need for careful and continuous curation of information being collected, regular database updates, and the need for a continued focus on data quality. As a standalone resource, each registry has supported numerous projects, but linkage with external datasets with patients in common has enhanced the research potential. Multiple projects have linked registry data with matched tissue specimens to support the discovery and valiation of prognostic and predictive markers in the tumour and blood specimens. Registry-based biomarker trials have been successfully supported, generating novel and practice-changing data. Registry-based clinical trials, particularly studies exploring the best use of drug options are now complementing the research conducted in traditional clinical trials. More recent projects supported by the registries include health economic studies, personalised patient education material, and increased consumer engagement, including consumer entered data.

Abstract

Traditional cancer registries have often been siloed efforts, established by single groups with limited objectives. There is the potential for registry data to support a broad range of research, audit and education initiatives. Here, we describe the establishment of a series of comprehensive cancer registries across the spectrum of common solid cancers. The experience and learnings of each registry team as they develop, implement and then use collected data for a range of purposes, that informs the conduct and output of other registries in a virtuous cycle. Each registry is multi-site, multi-disciplinary and aims to collect data of maximal interest and value to a broad range of enquiry, which would be accessible to any researcher with a high-quality proposal. Lessons learnt include the need for careful and continuous curation of data fields, with regular database updates, and the need for a continued focus on data quality. The registry data as a standalone resource has supported numerous projects, but linkage with external datasets with patients in common has enhanced the audit and research potential. Multiple projects have linked registry data with matched tissue specimens to support prognostic and predictive biomarker studies, both validation and discovery. Registry-based biomarker trials have been successfully supported, generating novel and practice-changing data. Registry-based clinical trials, particularly randomised studies exploring the optimal use of available therapy options are now complementing the research conducted in traditional clinical trials. More recent projects supported by the registries include health economic studies, personalised patient education material, and increased consumer engagement, including consumer entered data.

How Can the EU Beating Cancer Plan Help in Tackling Lung Cancer, Colorectal Cancer, Breast Cancer and Melanoma?

Cancer is the second leading cause of mortality in EU countries, and the needs to tackle cancer are obvious. New scientific understanding, techniques and methodologies are opening up horizons for significant improvements in diagnosis and care. However, take-up is uneven, research needs and potential outstrip currently available resources, manifestly beneficial practices—such as population-level screening for lung cancer—are still not generalised, and the quality of life of patients and survivors is only beginning to be given attention it merits. This paper, mainly based on a series of multistakeholder expert workshops organised by the European Alliance for Personalised Medicine (EAPM), looks at some of those specifics in the interest of planning a way forward. Part of this exercise also involves taking account of the specific nature of Europe and its constituent countries, where the complexities of planning a way forward are redoubled by the wide variations in national and regional approaches to cancer, local epidemiology and the wide disparities in health systems. Despite all the differences between cancers and national and regional resources and approaches to cancer care, there is a common objective in pursuing broader and more equal access to the best available care for all European citizens.

The impact of COVID-19 pandemic in the diagnosis and management of colorectal cancer patients

The novel coronavirus disease 2019 (COVID-19) pandemic has posed an unprecedented challenge to healthcare systems worldwide, causing downscaling of almost all other activities, especially in its early stages. Currently, the availability of vaccines along with the spread of new viral variants has modified the epidemiology of the disease, and the previous activity is being gradually resumed in most healthcare facilities. In this review, we have summarized the influence of the COVID-19 pandemic in the diagnosis and management of colorectal cancer (CRC) patients. Population-based screening with either colonoscopy or fecal occult blood tests has proven to reduce CRC incidence and mortality, so screening programs have been implemented in most western countries. However, during the first COVID-19 wave, most of these programs had to be disrupted temporarily. In this review, we have thoroughly analyzed the consequences of these disruptions of screening programs as well as of the forced delays in diagnostic and therapeutic services on CRC prognosis, although its exact impact cannot be exactly measured yet. In any way, strategies to minimize its effect, such as catch-up strategies expanding the colonoscopy capacity or using fecal occult blood concentration and other risk factors to prioritize patients, are urgently needed. The COVID-19 pandemic has also led to a change in CRC patient presentation, with an overall temporary decreased incidence due to postponed diagnoses, but with more patients presenting in need of an emergency admission or with symptoms. Finally, changes in treatment approaches in CRC patients have been reported during the pandemic, namely a drop in the proportion of laparoscopic surgeries or a rise in short-term radiotherapy courses. We have therefore aimed to summarize the available evidence to guide the healthcare professionals treating CRC patients to choose the best treatment options in the current pandemic situation.

A nomogram for predicting 10-year cancer specific survival in patients with pathological T3N0M0 rectal cancer

Background

The pathological T3N0M0 (pT3N0M0) rectal cancer is the earliest stage and has the best prognosis in the locally advanced rectal cancer, but the optimal treatment remains controversial. A reliable prognostic model is needed to discriminate the high-risk patients from the low-risk patients, and optimize adjuvant chemotherapy (ACT) treatment decisions by predicting the likelihood of ACT benefit for the target population.

Patients and methods

We gathered and analyzed 276 patients in Sun Yat-sen University Cancer Center from March 2005 to December 2011. All patients underwent total mesorectal excision (TME), without preoperative therapy, and were pathologically proven pT3N0M0 rectal cancer with negative circumferential resection margin (CRM). LASSO regression model was used for variable selection and risk factor prediction. Multivariable cox regression was used to develop the predicting model. Optimum cut-off values were determined using X-Tile plot analysis. The 10-fold cross-validation was adopted to validate the model. The performance of the nomogram was evaluated with its calibration, discrimination and clinical usefulness.

Results

A total of 188 patients (68.1%) had ACT and no patients had adjuvant radiotherapy. Age, monocyte percentage, carbohydrate antigen 19–9, lymph node dissection numbers and perineural invasion (PNI) were identified as significantly associated variables that could be combined for an accurate prediction risk of Cancer Specific Survival (CSS) for pT3N0M0 patients. The model adjusted for CSS showed good discrimination with a C-index of 0.723 (95% CI: 0.652–0.794). The calibration curves showed that the nomogram adjusted for CSS was able to predict 3-, 5-, and 10-year CSS accurately. The corresponding predicted probability was used to stratify high and low-risk patients (10-year CSS: 69.1% vs. 90.8%, HR = 3.815, 95%CI: 2.102–6.924, P < 0.0001). ACT improved overall survival (OS) in the low-risk patients (10-year OS: 91.9% vs. 83.3%, HR = 0.338, 95% CI: 0.135–0.848, P < 0.0001), while it did not exhibit a significant benefit in the high-risk patients.

Conclusion

The present study showed that age, monocyte percentage, carbohydrate antigen 19–9, lymph node dissection numbers and PNI were independent prognostic factors for pT3N0M0 rectal cancer patients. A nomogram based on these prognostic factors effectively predicts CSS in patients, which can be conveniently used in clinical practice. ACT may improve overall survival in the low-risk patients. But the benefit of ACT was not seen in the high-risk patients.

Serial Circulating Tumor DNA in Monitoring the Effect of Neoadjuvant and Adjuvant Immunotherapy in Patients With Colon Cancer: Case Series and Review of the Literature

Although programmed death 1 blockade has significantly improved the survival of advanced colorectal cancer patients with DNA mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H), clinical data in neoadjuvant and adjuvant setting are limited. The role of circulating tumor DNA (ctDNA) in precision oncology is promising, but its clinical significance in immunotherapy needs to be validated. We report a case series of 3 colon patients who received neoadjuvant and adjuvant immunotherapy and serial ctDNA analysis. This report summarizes clinical and molecular details for 3 patients with locally advanced or recurrent dMMR/MSI-H/polymerase epsilon (POLE) mutation-positive tumors treated with neoadjuvant/adjuvant immunotherapy. One stage IV recurrent colon cancer patient diagnosed with Lynch syndrome received adjuvant sintilimab monotherapy and had a progression-free survival (PFS) over 16 months, one stage Ⅲc colon cancer patient with MSI-H/high tumor mutation burden received neoadjuvant toripalimab monotherapy, was assessed as clinical complete response before surgery, continued with adjuvant sintilimab monotherapy and had a PFS over 17 months, one stage Ⅱ colon cancer patient with POLE P286R also received adjuvant sintilimab monotherapy and had a PFS over 17 months. All patients had detectable ctDNA after radical surgery and clearance of ctDNA during adjuvant immunotherapy. All 3 patients are free of tumor disease at the time of this report. Further studies are warranted to evaluate the long-term efficacy of neoadjuvant and adjuvant programmed death 1 blockade in locally advanced and metastasis in dMMR/MSI-H/POLE mutated colorectal cancer and the role of ctDNA monitoring.

Making the Rounds: Exploring the Role of Circulating Tumor DNA (ctDNA) in Non-Small Cell Lung Cancer

Advancements in the clinical practice of non-small cell lung cancer (NSCLC) are shifting treatment paradigms towards increasingly personalized approaches. Liquid biopsies using various circulating analytes provide minimally invasive methods of sampling the molecular content within tumor cells. Plasma-derived circulating tumor DNA (ctDNA), the tumor-derived component of cell-free DNA (cfDNA), is the most extensively studied analyte and has a growing list of applications in the clinical management of NSCLC. As an alternative to tumor genotyping, the assessment of oncogenic driver alterations by ctDNA has become an accepted companion diagnostic via both single-gene polymerase chain reactions (PCR) and next-generation sequencing (NGS) for advanced NSCLC. ctDNA technologies have also shown the ability to detect the emerging mechanisms of acquired resistance that evolve after targeted therapy. Furthermore, the detection of minimal residual disease (MRD) by ctDNA for patients with NSCLC after curative-intent treatment may serve as a prognostic and potentially predictive biomarker for recurrence and response to therapy, respectively. Finally, ctDNA analysis via mutational, methylation, and/or fragmentation multi-omic profiling offers the potential for improving early lung cancer detection. In this review, we discuss the role of ctDNA in each of these capacities, namely, for molecular profiling, treatment response monitoring, MRD detection, and early cancer detection of NSCLC.

Cancer Prevention Prioritized at AACR Annual Meeting and a New Working Group

Scientific advances in the late 19th century set the stage for progress in understanding and treating cancer, a disease that was previously considered almost hopeless. One hundred years later, cancer prevention is becoming an increasingly important focus for oncology research. New tools and ideas bring to the field some extremely promising molecular, organizational, social, and political approaches, which were a focus of the American Association for Cancer Research 2022 Annual Meeting and of the newly launched AACR Cancer Prevention Working Group (CPWG). We are moving toward precision prevention, better tools for early detection and for risk assessment, the use of a Precancer Atlas, unveiling of new biomarkers. Besides improving lifestyle, by avoiding risk factors such as tobacco use, excessive UV exposure, infectious agents, as well as poor dietary habits, lack of exercise, overweight, and obesity, many other factors can impact cancer risk, which is a warning to consider a multifaceted molecular but also social approach. Gender, ethnicity, geographic, and economic lines are associated with disparities in prevention, which we want to overcome. Here we summarize some challenges and priorities in cancer prevention emerging from the work of AACR and CPWG.

Liquid biopsy: blood-based analyses of circulating cell-free DNA in xenografts

The liquid biopsy concept has been introduced for circulating tumor cells more than 10 years ago (Pantel & Alix-Panabieres, 2010) and rapidly extended to cell-free DNA released from tumor cells (ctDNA; Lo et al, 2021) and other tumor-derived products such as circulating cell-free RNA (noncoding and messenger RNA), extracellular vesicles, or tumor-educated platelets (Alix-Panabières & Pantel, 2021). In this issue of EMBO Molecular Medicine, the report of Sauer et al (2022) demonstrates the feasibility of longitudinal monitoring of disease burden and response using ctDNA from dried blood spots in xenograft models.

Extracellular Nucleic Acids in the Diagnosis and Progression of Colorectal Cancer

Colorectal cancer (CRC) is the 3rd most common malignant neoplasm worldwide, with more than two million new cases diagnosed yearly. Despite increasing efforts in screening, many cases are still diagnosed at a late stage, when mortality is high. This paper briefly reviews known genetic causes of CRC (distinguishing between sporadic and familial forms) and discusses potential and confirmed nucleic acid biomarkers obtainable from liquid biopsies, classified by their molecular features, focusing on clinical relevance. We comment on advantageous aspects such as better patient compliance due to blood sampling being minimally invasive, the possibility to monitor mutation characteristics of sporadic and hereditary CRC in a disease showing genetic heterogeneity, and using up- or down-regulated circulating RNA markers to reveal metastasis or disease recurrence. Current difficulties and thoughts on some possible future directions are also discussed. We explore current evidence in the field pointing towards the introduction of personalized CRC management.

Liquid Biopsy in Pre-Metastatic Niche: From Molecular Mechanism to Clinical Application

Metastatic dissemination represents a hallmark of cancer that is responsible for the high mortality rate. Recently, emerging evidence demonstrates a time-series event—pre-metastatic niche (PMN) has a profound impact on cancer metastasis. Exosomes, cell-free DNA (cfDNA), circulating tumor cells (CTC), and tumor microenvironment components, as critical components in PMN establishment, could be monitored by liquid biopsy. Intensive studies based on the molecular profile of liquid biopsy have made it a viable alternative to tissue biopsy. Meanwhile, the complex molecular mechanism and intercellular interaction are great challenges for applying liquid biopsy in clinical practice. This article reviews the cellular and molecular components involved in the establishment of the PMN and the promotion of metastasis, as well as the mechanisms of their interactions. Better knowledge of the characteristics of the PMN may facilitate the application of liquid biopsy for clinical diagnosis, prognosis, and treatment.

Finding Waldo: The Evolving Paradigm of Circulating Tumor DNA (ctDNA)—Guided Minimal Residual Disease (MRD) Assessment in Colorectal Cancer (CRC)

Simple Summary

After the surgical removal of colorectal cancer (CRC), residual cancer cells undetectable by standard blood tests and imaging studies are responsible for cancer recurrence. Currently, chemotherapy is often administered after surgery to eradicate residual cancer cells, a decision guided by clinical and pathologic criteria, which are imprecise. Circulating tumor DNA (ctDNA) consists of DNA fragments in the bloodstream derived from cancer cells, and the presence of ctDNA likely indicates the presence of residual cancer cells. The current article discusses how ctDNA technology can help guide treatment in patients with CRC after curative surgery.

Abstract

Circulating tumor DNA (ctDNA), the tumor-derived cell-free DNA fragments in the bloodstream carrying tumor-specific genetic and epigenetic alterations, represents an emerging novel tool for minimal residual disease (MRD) assessment in patients with resected colorectal cancer (CRC). For many decades, precise risk-stratification following curative-intent colorectal surgery has remained an enduring challenge. The current risk stratification strategy relies on clinicopathologic characteristics of the tumors that lacks precision and results in over-and undertreatment in a significant proportion of patients. Consequently, a biomarker that can reliably identify patients harboring MRD would be of critical importance in refining patient selection for adjuvant therapy. Several prospective cohort studies have provided compelling data suggesting that ctDNA could be a robust biomarker for MRD that outperforms all existing clinicopathologic criteria. Numerous clinical trials are currently underway to validate the ctDNA-guided MRD assessment and adjuvant treatment strategies. Once validated, the ctDNA technology will likely transform the adjuvant therapy paradigm of colorectal cancer, supporting ctDNA-guided treatment escalation and de-escalation. The current article presents a comprehensive overview of the published studies supporting the utility of ctDNA for MRD assessment in patients with CRC. We also discuss ongoing ctDNA-guided adjuvant clinical trials that will likely shape future adjuvant therapy strategies for patients with CRC.

Circulating DNA in patients undergoing loco-regional treatment of colorectal cancer metastases: a systematic review and meta-analysis

Background

Loco-regional treatment strategies of colorectal cancer (CRC) metastases are evolving, but biological markers that can benefit patients and assist physicians in clinical decisions are lacking. The primary objective of this systematic review and meta-analysis is to investigate the current knowledge on circulating DNA and its clinical utility in predicting outcomes in patients undergoing loco-regional treatment of CRC metastases.

Methods

A systematic search of PubMed, Embase, and Cochrane Central Register of Controlled Trials was conducted on March 22, 2022. We included studies on patients undergoing loco-regional treatment of CRC metastases reporting the predictive or prognostic value of circulating DNA in the blood. Hazard ratios (HR) were pooled in separate random-effects meta-analyses to investigate if pre- or post-ablation measurements of circulating DNA were associated with survival. The risk of bias was assessed according to the Quality in Prognosis Studies tool.

Results

Twenty-eight studies with 2868 patients were included, of which 16 studies were eligible for meta-analyses. As expected in this new research field, a majority of included studies (n = 21/28) had a high risk of bias in at least one domain. Circulating DNA above the cutoff in a plasma sample taken before loco-regional treatment was associated with a short recurrence-free survival [pooled HR = 2.8, 95% confidence interval (CI) 1.4-5.7, n = 162] and overall survival (pooled HR = 4.7, 95% CI 1.1-20.6, n = 105). Circulating DNA above the cutoff in a plasma sample taken after loco-regional treatment was associated with a short recurrence-free survival (pooled HR = 4.5, 95% CI 3.4-6.1, n = 569) and overall survival (pooled HR = 7.5, 95% CI 2.0-27.3, n = 161). There was limited data on the association between dynamics in circulating DNA and outcome.

Conclusions

Measurements of circulating DNA can be valuable when selecting and monitoring patients undergoing loco-regional treatment of CRC metastases. Studies designed to investigate the true clinical utility of circulating DNA in the context of various ablation modalities are warranted.The review has been registered at PROSPERO (ID: CRD42022320032).