Applications of Liquid Biopsy for Surgical Patients With Cancer: A Review

Importance

Liquid biopsy is an emerging tool with the potential to change oncologic care practices. Optimal clinical applications for its use are currently undefined for surgical patients.

Observations

Liquid biopsy analytes such as circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) have been the most clinically studied assays and were initially limited to advanced-stage disease. In the metastatic setting, CTCs and ctDNA levels are prognostic. Although their levels correlate with treatment response, CTC-guided systemic regimen switches for nonresponders have not been shown to improve clinical outcomes. ctDNA genomic profiling has succeeded, and there are now multiple plasma-based assays approved by the US Food and Drug Administration that can detect actionable mutations to guide systemic therapy. Technological advancements in assay sensitivity have expanded the use of ctDNA to early-stage and resectable disease, allowing for detection of minimal residual disease. Postoperative ctDNA levels are a strong predictor of disease recurrence, and ctDNA detection often precedes serum carcinoembryonic antigen elevation and radiographic changes. However, its use for surveillance has not been shown to improve clinical outcomes. A promising application of ctDNA is for adjuvant therapy escalation and de-escalation. A phase 2 clinical trial demonstrated that treatment de-escalation for patients with high-risk stage II colorectal cancer and negative postoperative ctDNA had similar recurrence-free survival as patients receiving standard-of-care chemotherapy. These results suggest that ctDNA may help select patients who will benefit from adjuvant chemotherapy, and multiple clinical trials are actively underway.

Conclusions and Relevance

Although uncertainties regarding the optimal use of liquid biopsy remain, it has the potential to significantly improve care for patients with cancer at all stages of disease. It is critical that surgeons understand how to use and interpret these assays, and they should be active participants in clinical trials to advance the field.

Clinical application of circulating tumour DNA in colorectal cancer

Liquid biopsies that detect circulating tumour DNA (ctDNA) have the potential to revolutionise the personalised management of colorectal cancer. For patients with early-stage disease, emerging clinical applications include the assessment of molecular residual disease after surgery, the monitoring of adjuvant chemotherapy efficacy, and early detection of recurrence during surveillance. In the advanced disease setting, data highlight the potential of ctDNA levels as a prognostic marker and as an early indicator of treatment response. ctDNA assessment can complement standard tissue-based testing for molecular characterisation, with the added ability to monitor emerging mutations under the selective pressure of targeted therapy. Here we provide an overview of the evidence supporting the use of ctDNA in colorectal cancer, the studies underway to address some of the outstanding questions, and the barriers to widespread clinical uptake.

Report from the 24th Annual Western Canadian Gastrointestinal Cancer Consensus Conference on Colorectal Cancer, Richmond, British Columbia, 28-29, October 2022

The 24th annual Western Canadian Gastrointestinal Cancer Consensus Conference (WCGCCC) was held in Richmond, British Columbia, on 28-29 October 2022. The WCGCCC is an interactive multidisciplinary conference attended by healthcare professionals from across Western Canada (British Columbia, Alberta, Saskatchewan, and Manitoba) who are involved in the care of patients with gastrointestinal cancer. Surgical, medical, and radiation oncologists; pathologists; radiologists; and allied health care professionals such as dieticians, nurses and a genetic counsellor participated in presentation and discussion sessions for the purpose of developing the recommendations presented here. This consensus statement addresses current issues in the management of colorectal cancer.

Circulating tumor DNA in early-stage colon cancer: ready for prime time or needing refinement?

Liquid biopsies are the detection of molecular information in fluids from patients with cancer. In colorectal cancer (CRC), the most promising liquid biopsy strategy is the use of circulating tumor DNA (ctDNA) from plasma. In early-stage CRC, the potential for ctDNA to impact care stems from the detection of minimal residual disease (MRD) to guide adjuvant therapy after curative intent treatment and in identifying recurrences during surveillance. As for any new diagnostic test, ctDNA assays must overcome pre-analytical and analytical challenges before clinical implementation. We will discuss important logistical and assay considerations that clinicians and patients should understand when assessing ctDNA assays. We will also delve into important concepts to aid in interpreting ctDNA results and potential incidental findings that may arise. Sequencing errors, germline variants, and clonal hematopoiesis of indeterminate potential (CHIP) must be addressed to properly interpret results. CHIP is also an important consideration that impacts patient prognosis through association with cardiovascular and hematologic diseases. With this background in place, we next review the best available evidence for the use of ctDNA in early-stage colon cancer. Observational cohorts have established MRD after surgery as a significant prognostic factor for recurrence in stage II and III colon cancer. It also has the ability to anticipate clinical recurrence before standard investigations when used in surveillance. The first and only interventional randomized trial to date evaluating ctDNA is DYNAMIC. The study demonstrated the noninferiority of a MRD detection-guided approach in selecting patients with stage II colon cancer for adjuvant treatment. Notwithstanding the important results, there are still important questions to be answered before ctDNA enters prime time in the clinic. However, future appears bright and ongoing trials will help clarify how to best use this technology in early-stage colon cancer.

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.

The current state of molecular profiling in gastrointestinal malignancies

This is a review of the current state of molecular profiling in gastrointestinal (GI) cancers and what to expect from this evolving field in the future. Individualized medicine is moving from broad panel testing of numerous genes or gene products in tumor biopsy samples, identifying biomarkers of prognosis and treatment response, to relatively noninvasive liquid biopsy assays, building on what we have learned in our tumor analysis and growing into its own evolving predictive and prognostic subspecialty. Hence, the field of GI precision oncology is exploding, and this review endeavors to summarize where we are now in preparation for the journey ahead.

Cell-free circulating tumor DNA in colorectal cancer: a proof of concept with simplified methodology

BACKGROUND

Cell-free DNA analysis (cfDNA) holds promise for residual disease or tumor burden quantification in colorectal cancer, with reduced costs and diagnostic equipment compared to gold standard-specific tumor DNA (ctDNA) analysis.

METHODS

This prospective case-control study included 46 colorectal cancer patients and healthy controls to perform cfDNA quantification by fluorometry using Quantus Fluorometer (Promega, Madison, WI) and using cell-free DNA ScreenTape assay (Agilent) and 4200 TapeStation instrument (Agilent Technologies, Inc., Santa Clara, CA, USA). cfDNA quantification results were correlated with stage, clinical and histopathological features.

RESULTS

33 localized (8 stage I, 12 stage II, and 13 stage III) and 13 advanced colorectal cancer patients were included. No differences in cfDNA quantification by fluorometry were demonstrated depending on stage or histopathological features in localized disease patients. Differences in cfDNA quantification by fluorometry could be demonstrated in patients with advanced disease depending on the presence of liver metastases and synchronous or metachronous metastatic disease. Differences in cfDNA quantification by fluorometry could be demonstrated between advanced colorectal cancer patients and both localized disease patients and healthy controls. Secondary cfDNA analysis by electrophoresis, although showing more specificity to measure ctDNA in cfDNA values, could not improve the capacity to detect differences between analyzed a groups beyond previously achieved with fluorometry.

CONCLUSION

This exploratory analysis of cfDNA based on fluorometry and electrophoresis methods showed promising results discriminating colorectal cancer and non-cancer patients, as well as different colorectal cancer stages and disease profiles. Further studies are needed to increase our knowledge and to help to overcome barriers to broader implementation and applications.

Circulating tumor DNA (ctDNA) in adjuvant therapy of early stage colon cancer: current status and future perspectives

BACKGROUND

This article reviews the current knowledge on circulating tumor DNA (ctDNA) in early stage colon cancer and ongoing trials on ctDNA-guided treatment in the adjuvant setting.

METHODS

A literature search of Pubmed was performed to identify studies on ctDNA in early stage colon cancer and neoadjuvant or adjuvant treatment. For ongoing trials, we searched clinicaltrials.gov and the Australian New Zealand Clinical Trials Registry (ANZCTR).

RESULTS

Several studies show that ctDNA is a strong predictor for recurrence and survival after surgery and adjuvant chemotherapy. The specificity of this marker is extremely high, and the sensitivity is increasing with the development of technology. Recurrences can be detected very early and the analysis can potentially be used to guide neoadjuvant and adjuvant treatment. Ongoing and planned studies are now looking into escalation and de-escalation of therapy according to ctDNA-status after surgery.

CONCLUSION

Serial measurement of ctDNA shows great promise as a marker for both prognosis and response to treatment in early colon cancer. Future studies will show whether we can use this analysis for tailoring treatment for patients in the adjuvant and neoadjuvant setting. With improved technology, ctDNA has the potential of becoming a 'game-changer' in the treatment of early stage colon cancers.

Liquid biopsies for colorectal cancer: a narrative review of ongoing clinical trials and the current use of this technology at a comprehensive cancer center

OBJECTIVE

In this review, we summarize ongoing clinical trials involving liquid biopsies (LB) for colorectal cancer (CRC), outlining the current landscape and the future implementation of this technology. We also describe the current use of LB in CRC treatment at our institution, the Mayo Clinic Enterprise.

BACKGROUND

The use of LB in CRC treatment merits close attention. Their role is being evaluated in the screening, non-intervention, intervention, and surveillance settings through many active trials. This, coupled with the technique's rapid integration into clinical practice, creates constant evolution of care.

METHODS

Review of ClinicalTrials.gov was performed identifying relevant and active trials involving LB for CRC. "Colorectal cancer" plus other terms including "liquid biopsies" and "ctDNA" were used as search terms, identifying 35 active trials.

CONCLUSIONS

LB use for the CRC is actively being investigated and requires close attention. Based on current evidence, Mayo Clinic Enterprise currently uses LB in the non-interventional, interventional and surveillance setting, but not for screening. Results of these trials may further establish the use of LB in the management of CRC.

Potential utility of liquid biopsies in the management of patients with biliary tract cancers: A review

Biliary tract cancer, comprising gallbladder cancer, cholangiocarcinoma and ampullary cancer, represents a more uncommon entity outside high-endemic areas, though global incidence is rising. The majority of patients present at a late stage, and 5-year survival remains poor. Advanced stage disease is incurable, and though palliative chemotherapy has been shown to improve survival, further diagnostic and therapeutic options are required in order to improve patient outcomes. Although certain subtypes of biliary tract cancer are relatively rich in targetable mutations, attaining tumour tissue for histological diagnosis and treatment monitoring is challenging due to locoregional anatomical constraints and patient fitness. Liquid biopsies offer a safe and convenient alternative to invasive procedures and have great potential as diagnostic, predictive and prognostic biomarkers. In this review, the current standard of care for patients with biliary tract cancer, future treatment horizons and the possible utility of liquid biopsies within a variety of contexts will be discussed. Circulating tumour DNA, circulating microRNA and circulating tumour cells are discussed with an overview of their potential applications in management of biliary tract cancer. A summary is also provided of currently recruiting clinical trials incorporating liquid biopsies within biliary tract cancer research.

Use of Molecular Assays and Circulating Tumor DNA in Early-Stage Colorectal Cancer: A Roundtable Discussion of the Gastrointestinal Cancer Therapy Expert Group

The use of genomic testing is rapidly emerging as an important clinical tool both for cancer diagnosis and for guiding treatment decisions in a wide range of malignancies, including gastrointestinal (GI) cancers such as colorectal cancer (CRC). Advances in technologies such as polymerase chain reaction and next-generation sequencing methods have made it possible to noninvasively screen for CRC through, for example, the use of blood- or stool-based testing, with high specificity. Tests are also available that can provide prognostic information beyond traditional clinicopathologic factors such as tumor size, grade, and nodal status, which can enable clinicians to more accurately risk stratify patients for recurrence. Lastly, in the setting of resected CRC, tests are now available that can detect circulating tumor DNA as a means for noninvasive minimal/molecular residual disease monitoring, thereby potentially guiding the use of adjuvant chemotherapy and/or escalating or de-escalating therapy. The Gastrointestinal Cancer Therapy Expert Group (GICTEG) recently convened a virtual meeting to discuss current issues related to genomic testing in GI cancer, with the goal of providing guidance on the use of these tests for the practicing community oncologist, for whom GI cancer may be only one of many tumor types encountered. This article provides a summary of the discussion and highlights the key opinions of the GICTEG on this topic. IMPLICATIONS FOR PRACTICE: The Gastrointestinal Cancer Therapy Expert Group seeks to provide practical guidance and opinion on the treatment of gastrointestinal malignancies, including colorectal cancer (CRC), for the practicing community oncologist in situations for which guidelines from established bodies, such as the National Comprehensive Cancer Network and the American Society of Clinical Oncology, may be less clear. In the present report, clinical guidance on the use of molecular assays for a range of clinical indications in CRC is presented, including the use of circulating tumor DNA to detect minimal/molecular residual disease in patients with successfully resected early-stage CRC.

The Provocative Roles of Platelets in Liver Disease and Cancer

Both platelets and the liver play important roles in the processes of coagulation and innate immunity. Platelet responses at the site of an injury are rapid; their immediate activation and structural changes minimize the loss of blood. The majority of coagulation proteins are produced by the liver—a multifunctional organ that also plays a critical role in many processes: removal of toxins and metabolism of fats, proteins, carbohydrates, and drugs. Chronic inflammation, trauma, or other causes of irreversible damage to the liver can dysregulate these pathways leading to organ and systemic abnormalities. In some cases, platelet-to-lymphocyte ratios can also be a predictor of disease outcome. An example is cirrhosis, which increases the risk of bleeding and prothrombotic events followed by activation of platelets. Along with a triggered coagulation cascade, the platelets increase the risk of pro-thrombotic events and contribute to cancer progression and metastasis. This progression and the resulting tissue destruction is physiologically comparable to a persistent, chronic wound. Various cancers, including colorectal cancer, have been associated with increased thrombocytosis, platelet activation, platelet-storage granule release, and thrombosis; anti-platelet agents can reduce cancer risk and progression. However, in cancer patients with pre-existing liver disease who are undergoing chemotherapy, the risk of thrombotic events becomes challenging to manage due to their inherent risk for bleeding. Chemotherapy, also known to induce damage to the liver, further increases the frequency of thrombotic events. Depending on individual patient risks, these factors acting together can disrupt the fragile balance between pro- and anti-coagulant processes, heightening liver thrombogenesis, and possibly providing a niche for circulating tumor cells to adhere to—thus promoting both liver metastasis and cancer-cell survival following treatment (that is, with minimal residual disease in the liver).

Elevated serum carcinoembryonic antigen level after curative surgery is a prognostic biomarker of stage II-III colorectal cancer

BACKGROUND

High preoperative carcinoembryonic antigen (CEA) is a well-known risk factor for stage II-III colorectal cancer (CRC); however, in most cases, cancer does not recur. Conversely, postoperative CEA (post-CEA) is occasionally measured, and high post-CEA patients often develop recurrence; however, the clinical significance of post-CEA testing is unknown. The purpose of this study was to determine whether post-CEA elevation might indicate a poor prognosis for stage II-III CRC patients who underwent curative surgery.

PATIENTS AND METHODS

482 patients with pathological stage II-III CRC were included. Univariate and multivariate analyses were performed to evaluate post-CEA levels.

RESULTS

Multivariate analysis showed that elevated post-CEA (hazard ratio (HR): 3.14, P < 0.001), pathological lymph node metastasis (pN+), and pathological T4 (pT4) are associated with poor recurrence-free survival (RFS), and that elevated post-CEA (HR: 3.12; P = 0.002), pN+, pT4, age >70, and smoking are independently associated with poor overall survival. Subgroup analysis among stage III patients, in combination with the risk classification of the International Duration Evaluation of Adjuvant Chemotherapy (IDEA) study, showed that elevated post-CEA is a significant indicator of poor prognosis for RFS in both low-risk (73.8% vs. 21.2%, P < 0.001) and high-risk (49.9% vs. 25.0%, P = 0.04) groups.

CONCLUSIONS

Post-surgical CEA elevation is independently associated with poor prognosis in stage II-III CRC. Adding post-CEA levels to the IDEA risk classification may provide a more reliable indicator of the need for individualized surveillance and adjuvant chemotherapeutic strategies.