Prospective Feasibility Study for Using Cell-Free Circulating Tumor DNA-Guided Therapy in Refractory Metastatic Solid Cancers: An Interim Analysis

Travel Time and Distance and Participation in Precision Oncology Trials at the National Cancer Center Hospital

Importance

Genotype-matched trials, which are becoming increasingly important in the precision oncology era, require referrals from institutions providing comprehensive genomic profiling (CGP) testing to those conducting these trials, and the travel burden for trial participation is significant. However, it remains unknown whether travel time or distance are associated with genotype-matched trial participation.

Objective

To assess whether travel time or distance are associated with disparities in genotype-matched trial participation following CGP testing.

Design, Setting, and Participants

This retrospective cohort study from June 2020 to June 2022 included patients with advanced or metastatic solid tumors referred to the National Cancer Center Hospital for participation in genotype-matched trials following CGP testing and discussion by molecular tumor boards. Data were analyzed from June to October 2022.

Exposures

Travel time and distance.

Main Outcomes and Measures

The primary and secondary outcomes were enrollment in genotype-matched trials and all-cancer clinical trials, respectively.

Results

Of 1127 patients (mean [range] age, 62 [16-85] years; 584 women [52%]; all residents of Japan), 127 (11%) and 241 (21%) were enrolled in genotype-matched trials and all-cancer clinical trials, respectively. The overall median (IQR) travel distance and time were 38 (21-107) km and 55 (35-110) minutes, respectively. On multivariable regression with 23 covariates, travel distance (≥100 km vs <100 km) was not associated with the likelihood of genotype-matched trial participation (26 of 310 patients [8%] vs 101 of 807 patients [12%]; odds ratio [OR], 0.64; 95% CI, 0.40-1.02), whereas in patients with travel time of 120 minutes or more, the likelihood of genotype-matched trial participation was significantly lower than those with travel time less than 120 minutes (19 of 276 patients [7%] vs 108 of 851 patients [13%]; OR, 0.51; 95% CI, 0.29-0.84). The likelihood of genotype-matched trial participation decreased as travel time increased from less than 40 (38 of 283 patients [13%]) to 40 to 120 (70 of 568 patients [12%]) and 120 or more (19 of 276 patients [7%]) minutes (OR, 0.74; 95% CI, 0.48-1.17; OR, 0.41; 95% CI, 0.22-0.74, respectively). Neither travel time nor distance were associated with the likelihood of all-cancer clinical trial participation.

Conclusions and Relevance

In this cohort study of patients undergoing CGP testing, an increased travel time was associated with a decreased likelihood of genotype-matched trial participation. This warrants further research on interventions, such as decentralization of clinical trials to mitigate travel burden.

Analytical device miniaturization for the detection of circulating biomarkers

Diverse (sub)cellular materials are secreted by cells into the systemic circulation at different stages of disease progression. These circulating biomarkers include whole cells, such as circulating tumour cells, subcellular extracellular vesicles and cell-free factors such as DNA, RNA and proteins. The biophysical and biomolecular state of circulating biomarkers carry a rich repertoire of molecular information that can be captured in the form of liquid biopsies for disease detection and monitoring. In this Review, we discuss miniaturized platforms that allow the minimally invasive and rapid detection and analysis of circulating biomarkers, accounting for their differences in size, concentration and molecular composition. We examine differently scaled materials and devices that can enrich, measure and analyse specific circulating biomarkers, outlining their distinct detection challenges. Finally, we highlight emerging opportunities in biomarker and device integration and provide key future milestones for their clinical translation.

Circulating tumor nucleic acids: biology, release mechanisms, and clinical relevance

BACKGROUND

Despite advances in early detection and therapies, cancer is still one of the most common causes of death worldwide. Since each tumor is unique, there is a need to implement personalized care and develop robust tools for monitoring treatment response to assess drug efficacy and prevent disease relapse.

MAIN BODY

Recent developments in liquid biopsies have enabled real-time noninvasive monitoring of tumor burden through the detection of molecules shed by tumors in the blood. These molecules include circulating tumor nucleic acids (ctNAs), comprising cell-free DNA or RNA molecules passively and/or actively released from tumor cells. Often highlighted for their diagnostic, predictive, and prognostic potential, these biomarkers possess valuable information about tumor characteristics and evolution. While circulating tumor DNA (ctDNA) has been in the spotlight for the last decade, less is known about circulating tumor RNA (ctRNA). There are unanswered questions about why some tumors shed high amounts of ctNAs while others have undetectable levels. Also, there are gaps in our understanding of associations between tumor evolution and ctNA characteristics and shedding kinetics. In this review, we summarize current knowledge about ctNA biology and release mechanisms and put this information into the context of tumor evolution and clinical utility.

CONCLUSIONS

A deeper understanding of the biology of ctDNA and ctRNA may inform the use of liquid biopsies in personalized medicine to improve cancer patient outcomes.

Clinical value of next-generation sequencing in guiding decisions regarding endocrine therapy for advanced HR-positive/HER-2-negative breast cancer

OBJECTIVE

The mechanism of acquired gene mutation plays a major role in resistance to endocrine therapy in hormone receptor (HR)-positive advanced breast cancer. Circulating tumor DNA (ctDNA) has been allowed for the assessment of the genomic profiles of patients with advanced cancer. We performed this study to search for molecular markers of endocrine therapy efficacy and to explore the clinical value of ctDNA to guide precise endocrine therapy for HR-positive/human epidermal growth factor receptor-2 (HER-2)-negative metastatic breast cancer patients.

METHODS

In this open-label, multicohort, prospective study, patients were assigned to four parallel cohorts and matched according to mutations identified in ctDNA: 1) activation of the phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway preferred mTOR inhibitor combined with endocrine therapy; 2) estrogen receptor 1 (ESR1) mutation preferred fulvestrant; 3) HER-2 mutations preferred pyrotinib; and 4) no actionable mutations received treatment according to the clinical situation. In all cohorts, patients were divided into compliance group and violation group. The primary outcome measure was progression-free survival (PFS), and the secondary outcome measure was overall survival (OS).

RESULTS

In all cohorts, the combined median PFS was 4.9 months, and median PFS for the compliance and violation groups was 6.0 and 3.0 months, respectively [P=0.022, hazard ratio (HR)=0.57]. Multivariate Cox regression model showed the risk of disease progression was lower in compliance group than in violation group (P=0.023, HR=0.55). Among the patients with HER-2 mutations, the median PFS was 11.1 months in the compliance group and 2.2 months in the violation group (P=0.011, HR=0.20). There was no significant difference in the median PFS between patients who did and did not comply with the treatment protocol in patients with activation of the PI3K/AKT/mTOR or ESR1 mutation.

CONCLUSIONS

The results suggest that ctDNA may help to guide the optimal endocrine therapy strategy for metastatic breast cancer patients and to achieve a better PFS. Next-generation sequencing (NGS) detection could aid in distinguishing patients with HER-2 mutation and developing new treatment strategies.

Liquid Biopsy for Biomarker Testing in Non-Small Cell Lung Cancer: A European Perspective

The development of targeted therapies has improved survival rates for patients with advanced non-small cell lung cancer (NSCLC). However, tissue biopsy is unfeasible or inadequate in many patients, limiting biomarker testing and access to targeted therapies. The increasing numbers of established and emerging biomarkers with available targeted treatments highlights the challenges associated with sequential single-gene testing and limited tissue availability. Multiplex next-generation sequencing (NGS) offers an attractive alternative and represents a logical next step, and in cases where the tumour is inaccessible, tissue biopsy yields insufficient tumour content, or when the patient’s performance status does not allow a tissue biopsy, liquid biopsy can provide valuable material for molecular diagnosis. Here, we explore the role of liquid biopsy (i.e., circulating cell-free DNA analysis) in Europe. Liquid biopsies could be used as a complementary approach to increase rates of molecular diagnosis, with the ultimate aim of improving patient access to appropriate targeted therapies. Expert opinion is also provided on potential future applications of liquid biopsy in NSCLC, including for cancer prevention, detection of early stage and minimum residual disease, monitoring of response to therapy, selection of patients for immunotherapy, and monitoring of tumour evolution to enable optimal adaptation/combination of drug therapies.

Leveraging the Fragment Length of Circulating Tumour DNA to Improve Molecular Profiling of Solid Tumour Malignancies with Next-Generation Sequencing: A Pathway to Advanced Non-invasive Diagnostics in Precision Oncology?

Circulating cell-free DNA (ccfDNA) has emerged as a promising diagnostic tool in oncology. Identification of tumour-derived ccfDNA (i.e. circulating tumour DNA [ctDNA]) provides non-invasive access to a malignancy’s molecular landscape to diagnose, inform therapeutic strategies, and monitor treatment efficacy. Current applications of ccfDNA to detect somatic mutations, however, have been largely constrained to tumour-informed searches and identification of common mutations because of the interaction between ctDNA signal and next-generation sequencing (NGS) noise. Specifically, the low allele frequency of ctDNA associated with non-metastatic and early-stage lesions may be indistinguishable from artifacts that accrue during sample preparation and NGS. Thus, using ccfDNA to achieve non-invasive and personalized molecular profiling to optimize individual patient care is a highly sought goal that remains limited in clinical practice. There is growing evidence, however, that further advances in the field of ccfDNA diagnostics may be achieved by improving detection of somatic mutations through leveraging the inherently shorter fragment lengths of ctDNA compared to non-neoplastic ccfDNA. Here, the origins and rationale for seeking to improve the mutation-based detection of ctDNA by using ccfDNA size profiling are reviewed. Subsequently, in vitro and in silico methods to enrich for a target ccfDNA fragment length are detailed to identify current practices and provide perspective into the potential of using ccfDNA size profiling to impact clinical applications in oncology.

A Patient With Locally Advanced Mismatch-Repair-Deficient Pancreatic Ductal Adenocarcinoma Successfully Treated With Neoadjuvant Immunotherapy

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with a dismal prognosis. Approximately 30% of patients present with locally advanced disease, defined as pancreatic tumor with invasion to adjacent structures, including the vasculatures that preclude an upfront surgical resection. Emerging data suggest that neoadjuvant therapy, typically consisting of systemic chemotherapy followed by concurrent chemoradiation, increases the likelihood of potentially curative R0 resection by downstaging the tumor and improves survival in patients with locally advanced PDAC. PDAC with deficient DNA mismatch repair (dMMR)/microsatellite instability-high molecular signature is exceedingly rare. The role of immunotherapy is emerging in various dMMR gastrointestinal tumors, both in the metastatic and neoadjuvant settings. However, the efficacy of immunotherapy in the neoadjuvant setting in patients with dMMR locally advanced PDAC remains unknown. Herein, we describe a patient who presented with unresectable dMMR locally advanced PDAC and underwent neoadjuvant immunotherapy with pembrolizumab that resulted in a remarkable reduction of the tumor size, rendering the tumor resectable. Furthermore, the presence of dMMR signature in the tumor was detected by circulating tumor DNA analysis. This is the first report, to our knowledge, of the successful use of neoadjuvant immunotherapy in a patient with locally advanced PDAC.

Prolonged response to treatment based on cell-free DNA analysis and molecular profiling in three patients with metastatic cancer: a case series

Background:

Patients with advanced and/or metastatic solid tumors have limited treatment options. Mutations that serve as biomarkers of carcinogenesis can be found in cell-free DNA of patients’ plasma. Analysis of circulating tumor DNA (ctDNA) was developed as a non-invasive, cost-effective alternative to tumor biopsy when such biopsy is not technically feasible or it is associated with high risk for complications. The role of ctDNA in precision oncology is promising but its clinical significance across tumor types remains to be validated. We report a case series of three heavily pretreated patients with advanced solid tumors who received matched targeted therapy based on ctDNA analysis and/or tumor molecular profiling.

Case presentation:

Three patients with advanced, metastatic cancer and the following characteristics are presented: a 71-year-old woman with ovarian cancer and BRCA2 mutation identified in ctDNA and tumor tissue was treated with a PARP inhibitor and achieved partial response by RECIST (Response Evaluation Criteria in Solid Tumors) for 22.6+ months; a 40-year-old woman with adenoid cystic carcinoma of the parotid gland was treated with a MEK/RAF pathway inhibitor on the basis of RAF1 amplification on ctDNA analysis and had stable disease for 20.2 months; and a 56-year-old woman with breast cancer and a BRCA1 mutation identified by ctDNA analysis was treated with a PARP inhibitor and achieved stable disease for 9.1 months. All three patients are alive at the time of this report.

Conclusions:

These results suggest that ctDNA analysis can contribute to selection of targeted therapy in patients with advanced, metastatic cancer. Prospective clinical trials to evaluate and optimize ctDNA biomarkers, as well as the integration of novel and/or alternative targeted therapies, are warranted to fully assess the role of ctDNA analysis in cancer therapy.

Trial registration:

www.clinicaltrials.gov (NCT02152254). Registered May 28, 2014. https://www.clinicaltrials.gov/ct2/show/NCT02152254. MD Anderson protocol # PA12-1161 (approval ID IRB1 FWA00000121) and # PA11-0377 (approval ID IRB4 FWA00005015).

Circulating tumour DNA in metastatic breast cancer to guide clinical trial enrolment and precision oncology: A cohort study

BACKGROUND

Metastatic breast cancer (mBC) is a heterogenous disease with increasing availability of targeted therapies as well as emerging genomic markers of therapeutic resistance, necessitating timely and accurate molecular characterization of disease. As a minimally invasive test, analysis of circulating tumour DNA (ctDNA) is well positioned for real-time genomic profiling to guide treatment decisions. Here, we report the results of a prospective testing program established to assess the feasibility of ctDNA analysis to guide clinical management of mBC patients.

METHODS AND FINDINGS

Two hundred thirty-four mBC patients (median age 54 years) were enrolled between June 2015 and October 2018 at the Peter MacCallum Cancer Centre, Melbourne, Australia. Median follow-up was 15 months (range 1-46). All patient samples at the time of enrolment were analysed in real time for the presence of somatic mutations. Longitudinal plasma testing during the course of patient management was also undertaken in a subset of patients (n = 67, 28.6%), according to clinician preference, for repeated molecular profiling or disease monitoring. Detection of somatic mutations from patient plasma was performed using a multiplexed droplet digital PCR (ddPCR) approach to identify hotspot mutations in PIK3CA, ESR1, ERBB2, and AKT1. In parallel, subsets of samples were also analysed via next-generation sequencing (targeted panel sequencing and low-coverage whole-genome sequencing [LC-WGS]). The sensitivity of ddPCR and targeted panel sequencing to identify actionable mutations was compared. Results were discussed at a multidisciplinary breast cancer meeting prior to treatment decisions. ddPCR and targeted panel sequencing identified at least 1 actionable mutation at baseline in 80/234 (34.2%) and 62/159 (39.0%) of patients tested, respectively. Combined, both methods detected an actionable alteration in 104/234 patients (44.4%) through baseline or serial ctDNA testing. LC-WGS was performed on 27 patients from the cohort, uncovering several recurrently amplified regions including 11q13.3 encompassing CCND1. Increasing ctDNA levels were associated with inferior overall survival, whether assessed by ddPCR, targeted sequencing, or LC-WGS. Overall, the ctDNA results changed clinical management in 40 patients including the direct recruitment of 20 patients to clinical trials. Limitations of the study were that it was conducted at a single site and that 31.3% of participants were lost to follow-up.

CONCLUSION

In this study, we found prospective ctDNA testing to be a practical and feasible approach that can guide clinical trial enrolment and patient management in mBC.

Circulating tumor DNA analysis in the era of precision oncology

The spatial and temporal genomic heterogeneity of various tumor types and advances in technology have stimulated the development of circulating tumor DNA (ctDNA) genotyping. ctDNA was developed as a non-invasive, cost-effective alternative to tumor biopsy when such biopsy is associated with significant risk, when tumor tissue is insufficient or inaccessible, and/or when repeated assessment of tumor molecular abnormalities is needed to optimize treatment. The role of ctDNA is now well established in the clinical decision in certain alterations and tumors, such as the epidermal growth factor receptor (EGFR) mutation in non-small cell lung cancer and the v-Ki-ras2 kirsten rat sarcoma viral oncogene homolog (KRAS) mutation in colorectal cancer. The role of ctDNA analysis in other tumor types remains to be validated. Evolving data indicate the association of ctDNA level with tumor burden, and the usefulness of ctDNA analysis in assessing minimal residual disease, in understanding mechanisms of resistance to treatment, and in dynamically guiding therapy. ctDNA analysis is increasingly used to select therapy. Carefully designed clinical trials that use ctDNA analysis will increase the rate of patients who receive targeted therapy, will elucidate our understanding of evolution of tumor biology and will accelerate drug development and implementation of precision medicine. In this article we provide a critical overview of clinical trials and evolving data of ctDNA analysis in specific tumors and across tumor types.

Matched Whole-Genome Sequencing (WGS) and Whole-Exome Sequencing (WES) of Tumor Tissue with Circulating Tumor DNA (ctDNA) Analysis: Complementary Modalities in Clinical Practice

Tumor heterogeneity, especially intratumoral heterogeneity, is a primary reason for treatment failure. A single biopsy may not reflect the complete genomic architecture of the tumor needed to make therapeutic decisions. Circulating tumor DNA (ctDNA) is believed to overcome these limitations. We analyzed concordance between ctDNA and whole-exome sequencing/whole-genome sequencing (WES/WGS) of tumor samples from patients with breast (n = 12), gastrointestinal (n = 20), lung (n = 19), and other tumor types (n = 13). Correlation in the driver, hotspot, and actionable alterations was studied. Three cases in which more-in-depth genomic analysis was required have been presented. A total 58% (37/64) of patients had at least one concordant mutation. Patients who had received systemic therapy before tissue next-generation sequencing (NGS) and ctDNA analysis showed high concordance (78% (21/27) vs. 43% (12/28) p = 0.01, respectively). Obtaining both NGS and ctDNA increased actionable alterations from 28% (18/64) to 52% (33/64) in our patients. Twenty-one patients had mutually exclusive actionable alterations seen only in either tissue NGS or ctDNA samples. Somatic hotspot mutation analysis showed significant discordance between tissue NGS and ctDNA analysis, denoting significant tumor heterogeneity in these malignancies. Increased tissue tumor mutation burden (TMB) positively correlated with the number of ctDNA mutations in patients who had received systemic therapy, but not in treatment-naïve patients. Prior systemic therapy and TMB may affect concordance and should be taken into consideration in future studies. Incorporating driver, actionable, and hotspot analysis may help to further refine the correlation between these two platforms. Tissue NGS and ctDNA are complimentary, and if done in conjunction, may increase the detection rate of actionable alterations and potentially therapeutic targets.

Detection of ERBB2 (HER2) Gene Amplification Events in Cell-Free DNA and Response to Anti-HER2 Agents in a Large Asian Cancer Patient Cohort

Background: HER2 antagonists have marked activity and are approved for the treatment of HER2 overexpressing breast and gastric cancers. Recent studies have shown that ERBB2 (HER2) gene amplification and overexpression may also be actionable in other tumor types. Inter- and intratumoral heterogeneity in HER2 status, however, poses a significant challenge in identifying patients that may benefit from HER2-targeted therapies. ERBB2 amplification as identified by circulating cell-free DNA (cfDNA), which circumvents tissue heterogeneity issues, is emerging as a robust biomarker predictive of response to anti-HER2 agents. Here, the prevalence and genomic landscape of ERBB2 alterations detectable by next-generation sequencing (NGS) of cfDNA was evaluated in a large cohort of Asian patients with advanced solid tumors. Methods: Results were queried for consecutive patients (n = 469) tested by a comprehensive 70/73-gene cfDNA NGS assay (Guardant360®) between November 2015 and June 2018. Patients with ERBB2 gene alterations including copy number amplifications (CNAs), single nucleotide variants (SNVs), and insertion-deletions (indels) were identified. Results: ERBB2 alterations were detected in 52 patients (11.1%); ERBB2 SNVs, CNAs, and indels were found in 27 (5.8%), 27 (5.8%), and 10 (2.1%) patients, respectively. ERBB2 amplification was most frequently identified in gastric (21.4%; 6/28), colorectal (11.1%; 5/45), lung (3.9%; 9/231), and breast (3.2%; 1/31) cancer patients. ERBB2 amplification was often mutually exclusive with other oncogenic alterations in gastric (83.3%; 5/6) and colorectal (60%; 3/5) cancer patients. ERBB2 copy number gains were also highest in gastric and colorectal cancers (median 4.8 and 6.6, respectively). We further report two cases of advanced gastric cancer patients, one treatment naïve, and the other having failed four lines of therapy, whose ERBB2 CNAs were identified by cfDNA and derived clinical benefit from HER2-based therapies. Conclusion: Our data indicate that ERBB2 amplification is a common event in solid tumors among Asian cancer patients. High ERBB2 incidence and copy number gains were observed in gastric and colorectal cancer patients, often in the absence of other oncogenic mutations, underscoring its likely role as the driver alteration in those settings. Finally, we show the potential of comprehensive cfDNA testing in identifying patients who are most likely to benefit from HER2-targeted therapies.

Real-World Utility of an Amplicon-Based Next-Generation Sequencing Liquid Biopsy for Broad Molecular Profiling in Patients With Advanced Non-Small-Cell Lung Cancer

PURPOSE

To assess the feasibility and utility of circulating tumor DNA (ctDNA) by amplicon-based next-generation sequencing (NGS) analysis in the daily clinical setting in a cohort of patients with advanced non-small-cell lung cancer (NSCLC), as an alternative approach to tissue molecular profiling.

PATIENTS AND METHODS

In this single-center prospective study, treatment-naïve and previously treated patients with advanced NSCLC were enrolled. Clinical validation of ctDNA using amplicon-based NGS analysis (with a 36-gene panel) was performed against standard-of-care tissue molecular analysis in treatment-naïve patients. The feasibility, utility, and prognostic value of ctDNA as a dynamic marker of treatment efficacy was evaluated. Results of tissue molecular profile were blinded during ctDNA analysis.

RESULTS

Of 214 patients with advanced NSCLC who were recruited, 156 were treatment-naïve patients and 58 were pretreated patients with unknown tissue molecular profile. ctDNA screening was successfully performed for 91% (n = 194) of all patients, and mutations were detected in 77% of these patients. Tissue molecular analysis was available for 111 patients (52%), and tissue somatic mutations were found for 78% (n = 87) of patients. For clinically relevant variants, concordance agreement between ctDNA and tumor tissue analysis was 95% among 94 treatment-naïve patients who had concurrent liquid and tumor biopsy molecular profiles. Sensitivity and specificity were 81% and 97%, respectively. Of the 103 patients with no tissue available, ctDNA detected potential actionable mutations in 17% of patients; of these, 10% received personalized treatment. ctDNA kinetics correlated with response rate and progression-free survival in 31 patients treated with first-line platinum-based chemotherapy.

CONCLUSION

These real-world data from a prospective study endorse ctDNA molecular profile by amplicon-based NGS as an accurate and reliable tool to detect and monitor clinically relevant molecular alterations in patients with advanced NSCLC.

Cell-Free DNA Profiling to Discover Mechanisms of Exceptional Response to Cabozantinib Plus Panitumumab in a Patient With Treatment Refractory Metastatic Colorectal Cancer

MET amplification is rare in treatment-naïve metastatic colorectal cancer (CRC) tumors, but can emerge as a mechanism of resistance to anti-EGFR therapies. Preclinical and clinical data suggest that patients with MET amplified tumors benefit from MET-targeted therapy. Cabozantinib is an inhibitor of multiple tyrosine kinases, included c-MET. Panitumumab is an inhibitor of EGFR. This report describes a patient with KRAS, NRAS, and BRAF wild-type metastatic CRC who experienced disease progression on all standard chemotherapy and anti-EGFR antibody therapy. The patient was enrolled in a clinical trial evaluating the combination of cabozantinib plus panitumumab. After only 6 weeks of treatment, the patient experienced a significant anti-tumor response. Although tumor tissue was negative for MET amplification, molecular profiling of cell-free DNA (cfDNA) revealed MET amplification. This case represents the first report showing the activity of cabozantinib in combination with panitumumab in a patient with metastatic CRC, and suggests that MET amplification in cfDNA may be a biomarker of response. A clinical trial targeting MET amplified metastatic CRC is currently underway.

The Clinical Landscape of Circulating Tumor DNA in Gastrointestinal Malignancies

Technologies for genomic analyses have revealed more details in cancer biology and have changed standard treatments for cancer, including the introduction of targeted gene-specific therapy. Currently, liquid biopsies are increasingly being utilized in clinical trials and research settings to analyze circulating tumor DNA (ctDNA) from peripheral blood. Several studies have shown the potential of ctDNA in the screening, prognostication, molecular profiling, and monitoring of gastrointestinal malignancies. Although limitations continue to exist in the use of ctDNA, such as method standardization, the sensitivity, concordance with tumor tissue, and regulatory issues, this field offers promising benefits for cancer treatment. A deeper understanding of tumor biology via ctDNA analyses and ctDNA-guided clinical trials will lead to the increasing use of ctDNA in clinical practice in the near future; this development will result in the improvement of outcomes among patients with gastrointestinal malignancies.

Secondary Germline Finding in Liquid Biopsy of a Deceased Patient; Case Report and Review of the Literature

Liquid biopsies are increasingly used in the care of patients with advanced cancers. These tests are used to find mutations and other genomic alterations, quantify these findings over time, and guide treatment. It is not unexpected that germline mutations contributing to the development of cancer can be identified in cell-free DNA. Consequently, increased use of liquid biopsies has resulted in subsequent rise of secondary identification of germline mutations. Clinicians need to be aware of this potential use of liquid biopsies and the need to evaluate the patient and family members for confirmation. Our case documents a deceased patient's liquid biopsy result that was confirmed as a germline mutation through a methodical work-up of the patient's family members. Here, we present the case and provide a brief review of pertinent literature.

Incorporating blood-based liquid biopsy information into cancer staging: time for a TNMB system?

Tissue biopsy is the standard diagnostic procedure for cancer. Biopsy may also provide material for genotyping, which can assist in the diagnosis and selection of targeted therapies but may fall short in cases of inadequate sampling, particularly from highly heterogeneous tumors. Traditional tissue biopsy suffers greater limitations in its prognostic capability over the course of disease, most obviously as an invasive procedure with potential complications, but also with respect to probable tumor clonal evolution and metastasis over time from initial biopsy evaluation. Recent work highlights circulating tumor DNA (ctDNA) present in the blood as a supplemental, or perhaps an alternative, source of DNA to identify the clinically relevant cancer mutational landscape. Indeed, this noninvasive approach may facilitate repeated monitoring of disease progression and treatment response, serving as a means to guide targeted therapies based on detected actionable mutations in patients with advanced or metastatic solid tumors. Notably, ctDNA is heralding a revolution in the range of genomic profiling and molecular mechanisms to be utilized in the battle against cancer. This review will discuss the biology of ctDNA, current methods of detection and potential applications of this information in tumor diagnosis, treatment, and disease prognosis. Conventional classification of tumors to describe cancer stage follow the TNM notation system, heavily weighting local tumor extent (T), lymph node invasion (N), and detectable metastasis (M). With recent advancements in genomics and bioinformatics, it is conceivable that routine analysis of ctDNA from liquid biopsy (B) may make cancer diagnosis, treatment, and prognosis more accurate for individual patients. We put forward the futuristic concept of TNMB tumor classification, opening a new horizon for precision medicine with the hope of creating better outcomes for cancer patients.