Concurrent Tissue and Circulating Tumor DNA Molecular Profiling to Detect Guideline-Based Targeted Mutations in a Multicancer Cohort.

Importance: Tissue-based next-generation sequencing (NGS) of solid tumors is the criterion standard for identifying somatic mutations that can be treated with National Comprehensive Cancer Network guideline-recommended targeted therapies. Sequencing of circulating tumor DNA (ctDNA) can also identify tumor-derived mutations, and there is increasing clinical evidence supporting ctDNA testing as a diagnostic tool. The clinical value of concurrent tissue and ctDNA profiling has not been formally assessed in a large, multicancer cohort from heterogeneous clinical settings. Objective: To evaluate whether patients concurrently tested with both tissue and ctDNA NGS testing have a higher rate of detection of guideline-based targeted mutations compared with tissue testing alone. Design, Setting, and Participants: This cohort study comprised 3209 patients who underwent sequencing between May 2020, and December 2022, within the deidentified, Tempus multimodal database, consisting of linked molecular and clinical data. Included patients had stage IV disease (non-small cell lung cancer, breast cancer, prostate cancer, or colorectal cancer) with sufficient tissue and blood sample quantities for analysis. Exposures: Received results from tissue and plasma ctDNA genomic profiling, with biopsies and blood draws occurring within 30 days of one another. Main Outcomes and Measures: Detection rates of guideline-based variants found uniquely by ctDNA and tissue profiling. Results: The cohort of 3209 patients (median age at diagnosis of stage IV disease, 65.3 years [2.5%-97.5% range, 43.3-83.3 years]) who underwent concurrent tissue and ctDNA testing included 1693 women (52.8%). Overall, 1448 patients (45.1%) had a guideline-based variant detected. Of these patients, 9.3% (135 of 1448) had variants uniquely detected by ctDNA profiling, and 24.2% (351 of 1448) had variants uniquely detected by solid-tissue testing. Although largely concordant with one another, differences in the identification of actionable variants by either assay varied according to cancer type, gene, variant, and ctDNA burden. Of 352 patients with breast cancer, 20.2% (71 of 352) with actionable variants had unique findings in ctDNA profiling results. Most of these unique, actionable variants (55.0% [55 of 100]) were found in ESR1, resulting in a 24.7% increase (23 of 93) in the identification of patients harboring an ESR1 mutation relative to tissue testing alone. Conclusions and Relevance: This study suggests that unique actionable biomarkers are detected by both concurrent tissue and ctDNA testing, with higher ctDNA identification among patients with breast cancer. Integration of concurrent NGS testing into the routine management of advanced solid cancers may expand the delivery of molecularly guided therapy and improve patient outcomes.

Role of Tumor-informed Personalized Circulating Tumor DNA Assay in Informing Recurrence in Patients With Peritoneal Metastases From Colorectal and High-grade Appendix Cancer Undergoing Curative-intent Surgery.

OBJECTIVE: To investigate the role of a personalized, tumor-informed circulating tumor DNA (ctDNA) assay in informing recurrence in patients with peritoneal metastases (PM) from colorectal (CRC) and high-grade appendix (HGA) cancer after curative cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC). BACKGROUND: Over 50% of patients with CRC/HGA-PM recur after optimal CRS-HIPEC. The limited sensitivity of axial imaging and diagnostic biomarkers is a significant cause of delay in the detection of recurrence and initiation of further therapies. Plasma ctDNA has a promising role in monitoring response to treatment and/or recurrence after primary cancer resection. METHODS: Patients with CRC/HGA-PM who underwent curative CRS-HIPEC and serial postresection ctDNA assessments were included. Patients with rising postoperative ctDNA levels were compared with those with stable, undetectable ctDNA levels. Primary outcomes were the percentage of patients with recurrence and disease-free survival (DFS). Secondary outcomes were overall survival, ctDNA sensitivity, lead time, and performance of ctDNA compared with carcinoembryonic antigen. RESULTS: One hundred thirty serial postresection ctDNA assessments [median 4, interquartile range (IQR), 3 to 5] were performed in 33 patients (n = 13 CRC, n = 20 HGA) who underwent completeness of cytoreduction-0/1 CRS with a median follow-up of 13 months. Of the 19 patients with rising ctDNA levels, 90% recurred versus 21% in the stable ctDNA group (n = 14, < 0.001). Median DFS in the rising ctDNA cohort was 11 months (IQR, 6 to 12) and not reached in the stable ( P = 0.01). A rising ctDNA level was the most significant factor associated with DFS (hazard ratio: 3.67, 95% CI: 1.06-12.66, P = 0.03). The sensitivity and specificity of rising ctDNA levels in predicting recurrence were 85% and 84.6%, respectively. The median ctDNA lead time was 3 months (IQR, 1 to 4). Carcinoembryonic antigen was less sensitive (50%) than ctDNA. CONCLUSIONS: This study supports the clinical validity of serial ctDNA assessment as a strong prognostic biomarker in informing recurrence in patients with CRC/HGA-PM undergoing curative resection. It also holds promises for informing future clinical trial designs and further research.

Minimal Residual Disease-Directed Adjuvant Therapy for Patients With Early-Stage Colon Cancer: CIRCULATE-US.

BACKGROUND: The ability to detect circulating tumor DNA (ctDNA), a novel surrogate for minimal residual disease (MRD) for patients with solid tumors, has significantly evolved over the past decade. Several studies have shown that ctDNA may provide clinical insight into the biological dynamics of MRD. The CIRCULATE-US (NRG-GI008; NCT05174169) trial will aim to address the role of ctDNA for risk stratification to intensify and deintensify adjuvant chemotherapy for patients with early-stage colon cancer. METHODS: CIRCULATE-US, a prospective phase 2/3 randomized trial, is investigating the molecular dynamics and prognostic role of ctDNA (evaluated by Natera's Signatera assay) for patients with resected colon cancer. Patients with negative postoperative ctDNA will be enrolled in cohort A and randomized to receive either immediate treatment with 5-fluorouracil and folinic acid or capecitabine plus oxaliplatin (FOLFOX6 or CAPEOX; Arm 1) or serial ctDNA surveillance with delayed adjuvant therapy (Arm 2). Patients randomized to Arm 2 with subsequent positive ctDNA results will be enrolled in cohort B for a second randomization to receive either FOLFOX6/CAPEOX (Arm 3) or 5-fluorouracil, folinic acid, oxaliplatin, and irinotecan (FOLFIRINOX; Arm 4) for 6 months. Patients with positive postoperative ctDNA results will be directly enrolled in cohort B and randomized to receive either FOLFOX6/CAPEOX (Arm 3) or FOLFIRINOX (Arm 4). Patients with stage II or stage IIIC colon cancer with positive ctDNA results (tested as standard of care with commercial testing) will be eligible for enrollment in cohort B. The primary end point for cohort A is time to positive ctDNA status for phase 2 and disease-free survival for phase 3 with a noninferiority design. The primary end point for cohort B is disease-free survival for both phase 2 and phase 3 with a superiority design. DISCUSSION: CIRCULATE-US will aim to understand postoperative ctDNA dynamics in early-stage colon cancer and will investigate escalation and de-escalation approaches by using ctDNA status as a surrogate for MRD status.

Tumor Fraction Correlates With Detection of Actionable Variants Across > 23,000 Circulating Tumor DNA Samples.

PURPOSE: Profiling of circulating tumor DNA (ctDNA) is increasingly adopted in the management of solid tumors, concurrent with increased availability of more comprehensive ctDNA panels. However, variable ctDNA shed can result in variable assay sensitivity. We studied the relationship between ctDNA tumor fraction (TF) and detection of actionable alterations across cancer types. METHODS: A total of 23,482 liquid biopsies (LBx) submitted between September 2020 and October 2021 were sequenced using a hybrid capture panel that reports genomic alterations (GAs) and genomic biomarkers across 324 cancer-related genes. The primary end points were the prevalence of targetable GAs by cancer type and detection in relationship to ctDNA TF. Sensitivity of detection in LBx was assessed in 1,289 patients with available tissue results. RESULTS: 94% (n = 22,130) of LBx had detectable ctDNA, with a median TF of 2.2%. LBx profiling detected GAs in National Comprehensive Cancer Network category 1 genes in 37% of lung, 30% of prostate, 36% of breast, and 51% of colon cancer cases. Potential germline GAs flagged on clinical reports were detected in genes including BRCA1/2, PALB2, CHEK2, and ATM. Polyclonal mutations in genes associated with resistance such as AR, ESR1, RB1, and NF1 were detected. The sensitivity of LBx to detect driver alterations identified in tissue biopsy from the same patient ranged from 58% to 86% but was consistently at or near 100% in cases with TF ≥ 10%. CONCLUSION: Elevated ctDNA shed is associated with both high sensitivity and negative predictive value for detection of actionable GAs. The presence of elevated TF suggests adequate tumor profiling and may reduce the value of subsequent reflex to confirmatory tissue testing in patients with negative LBx results.

An ultrasensitive electrochemical self-signal circulating tumor DNA recognition strategy employing black phosphorous nanosheets assembled with flavin adenine dinucleotide.

A self-signal electrochemical sensing platform was constructed for direct recognition of circulating tumor DNA (ctDNA) employing black phosphorous nanosheets (BPNS) assembled with flavin adenine dinucleotide (FAD) prepared by ultrasonication approach. FAD provided a highly efficient and stable dispersing medium for acquiring highly dispersed BPNS in aqueous phase. The obtained FAD/BPNS nanocomposite exhibited favorable electrochemical redox activity and was utilized as the interface for the immobilization and hybridization of DNA. The amine-terminated probe ssDNA was covalently assembled onto the FAD/BPNS nanocomposite with plentiful phosphonate groups accompanied by the decrease of the self-signal. The self-redox signal of the nanointerface regenerated after the probe hybridized with the complementary sequence as a result of DNA transformation. Electrochemical response enhanced with complementary DNA concentration from 1.0 × 10-18 to 1.0 × 10-8 mol/L with a detection limit of 2.6 × 10-19 mol/L. The DNA determination platform revealed outstanding sensitivity, specificity and stableness, and was successfully employed in the detection of ctDNA associated with colorectal cancer. The developed biosensing strategy is simple to accomplish and has the potency for the application for diverse morbific gene without sophisticated label procedure.

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

BACKGROUND: The role of adjuvant chemotherapy in stage II colon cancer continues to be debated. The presence of circulating tumor DNA (ctDNA) after surgery predicts very poor recurrence-free survival, whereas its absence predicts a low risk of recurrence. The benefit of adjuvant chemotherapy for ctDNA-positive patients is not well understood. METHODS: We conducted a trial to assess whether a ctDNA-guided approach could reduce the use of adjuvant chemotherapy without compromising recurrence risk. Patients with stage II colon cancer were randomly assigned in a 2:1 ratio to have treatment decisions guided by either ctDNA results or standard clinicopathological features. For ctDNA-guided management, a ctDNA-positive result at 4 or 7 weeks after surgery prompted oxaliplatin-based or fluoropyrimidine chemotherapy. Patients who were ctDNA-negative were not treated. The primary efficacy end point was recurrence-free survival at 2 years. A key secondary end point was adjuvant chemotherapy use. RESULTS: Of the 455 patients who underwent randomization, 302 were assigned to ctDNA-guided management and 153 to standard management. The median follow-up was 37 months. A lower percentage of patients in the ctDNA-guided group than in the standard-management group received adjuvant chemotherapy (15% vs. 28%; relative risk, 1.82; 95% confidence interval [CI], 1.25 to 2.65). In the evaluation of 2-year recurrence-free survival, ctDNA-guided management was noninferior to standard management (93.5% and 92.4%, respectively; absolute difference, 1.1 percentage points; 95% CI, -4.1 to 6.2 [noninferiority margin, -8.5 percentage points]). Three-year recurrence-free survival was 86.4% among ctDNA-positive patients who received adjuvant chemotherapy and 92.5% among ctDNA-negative patients who did not. CONCLUSIONS: A ctDNA-guided approach to the treatment of stage II colon cancer reduced adjuvant chemotherapy use without compromising recurrence-free survival. (Supported by the Australian National Health and Medical Research Council and others; DYNAMIC Australian New Zealand Clinical Trials Registry number, ACTRN12615000381583.).

Early stage breast cancer follow-up in real-world clinical practice: the added value of cell free circulating tumor DNA.

PURPOSE: Physical examinations and annual mammography (minimal follow-up) are as effective as laboratory/imaging tests (intensive follow-up) in detecting breast cancer (BC) recurrence. This statement is now challenged by the availability of new diagnostic tools for asymptomatic cases. Herein, we analyzed current practices and circulating tumor DNA (ctDNA) in monitoring high-risk BC patients treated with curative intent in a comprehensive cancer center. PATIENTS AND METHODS: Forty-two consecutive triple negative BC patients undergoing neoadjuvant therapy and surgery were prospectively enrolled. Data from plasma samples and surveillance procedures were analyzed to report the diagnostic pattern of relapsed cases, i.e., by symptoms, follow-up procedures and ctDNA. RESULTS: Besides minimal follow-up, 97% and 79% of patients had at least 1 non-recommended imaging and laboratory tests for surveillance purposes. During a median follow-up of 5.1(IQR, 4.1-5.9) years, 13 events occurred (1 contralateral BC, 1 loco-regional recurrence, 10 metastases, and 1 death). Five recurrent cases were diagnosed by intensive follow-up, 5 by symptoms, and 2 incidentally. ctDNA antedated disseminated disease in all evaluable cases excepted two with bone-only and single liver metastases. The mean time from ctDNA detection to suspicious findings at follow-up imaging was 3.81(SD, 2.68), and to definitive recurrence diagnosis 8(SD, 2.98) months. ctDNA was undetectable in the absence of disease and in two suspected cases not subsequently confirmed. CONCLUSIONS: Some relapses are still symptomatic despite the extensive use of intensive follow-up. ctDNA is a specific test, sensitive enough to detect recurrence before other methods, suitable for clarifying equivocal imaging, and exploitable for salvage therapy in asymptomatic BC survivors.

Evaluation of Comparative Surveillance Strategies of Circulating Tumor DNA, Imaging, and Carcinoembryonic Antigen Levels in Patients With Resected Colorectal Cancer.

Importance: A circulating tumor DNA (ctDNA) assay (Signatera; Natera) has been marketed for use in the surveillance of resected colorectal cancer despite limited data supporting such practice. Objective: To compare a ctDNA assay with standard radiographic imaging and measurement of carcinoembryonic antigen (CEA) levels, per National Comprehensive Cancer Network guidelines, in the surveillance of resected colorectal cancer. Design, Setting, and Participants: This retrospective, single-center cohort study evaluated surveillance strategies of ctDNA, imaging, and measurement of CEA levels in patients with resected colorectal cancer from September 1, 2019, to November 30, 2021. Main Outcomes and Measures: The sensitivity and specificity of ctDNA, imaging, measurement of CEA levels, and combination of imaging plus measurement of CEA levels in detecting a confirmed recurrence of colorectal disease. A confirmed recurrence was defined as a positive ctDNA finding or a finding on imaging confirmed by biopsy, CEA level elevation, or subsequent tumor radiographic dynamics. Results: A total of 48 patients with curatively resected colorectal cancer satisfied the inclusion criteria for this study (28 men [58.3%]; median age, 60 [IQR, 34-85] years) and underwent surveillance by ctDNA, imaging, and measurement of CEA levels. Fifteen patients had disease recurrence during surveillance. Positive ctDNA findings confirmed disease recurrence in 8 patients; imaging, in 9 patients; CEA levels, in 3 patients; and combined imaging plus CEA levels, in 11 patients. Numerically, ctDNA did not perform better than imaging in detecting recurrence, with sensitivities of 53.3% (95% CI, 27.4%-77.7%) and 60.0% (95% CI, 32.9%-82.5%), respectively (P > .99). The combination of imaging plus measurement of CEA levels (sensitivity, 73.3% [95% CI, 44.8%-91.1%]) had a numerical advantage compared with ctDNA in identifying recurrence (P = .55). In addition, no significant difference was noted among ctDNA (median, 14.3 months), imaging (median, 15.0 months), or imaging plus measurement of CEA levels (median, 15.0 months) in the time to identify disease recurrence. Conclusions and Relevance: The findings of this cohort study suggest that ctDNA assay may not provide advantages as a surveillance strategy compared with standard imaging combined with CEA levels when performed per National Comprehensive Cancer Network guidelines.

Circulating Tumor DNA as a Potential Prognostic Marker in Patients with Borderline-Resectable Pancreatic Cancer Undergoing Neoadjuvant Chemotherapy Followed by Pancreatectomy.

BACKGROUND: Circulating tumor DNA (ctDNA) might be a promising biomarker for pancreatic cancer in liquid biopsy. This study aimed to evaluate the usefulness of liquid biopsy for patients with borderline-resectable pancreatic cancer (BR-PC). METHODS: Patients with BR-PC according to the National Comprehensive Cancer Network guidelines (2017) and eligible for neoadjuvant chemotherapy (NAC) followed by pancreatectomy were recruited at Wakayama Medical University Hospital (UMIN000026647) between March 2017 and April 2020. The study enrolled 55 patients with locally advanced PC, and each patient consented to inclusion in the study. The study investigated the relationship between KRAS status in ctDNA and clinicopathologic features, analyzing ctDNA at three time points: pretreatment, post-NAC, and post-operation. RESULTS: Of the 55 enrolled patients with a diagnosis of BR-PC, 34 were scheduled to undergo pancreatectomy. From 27 patients with resected BR-PC, 81 blood samples were analyzed in triplicate for ctDNA. The patients with positive pretreatment and post-NAC ctDNA status had no significant decrease in median relapse-free survival (RFS) or overall survival (OS). However, the patients with positive postoperation ctDNA status had a significantly shorter median OS (723 days) than the patients with negative ctDNA results (not reached; P = 0.0148). A combined analysis of postoperative ctDNA and CA19-9 values showed the cumulative effect on both RFS (P = 0.0066) and OS (P = 0.0046). The adjusted hazard ratio for risk of survival computed for the patients carrying risk factors (either detectable ctDNA or CA19-9 > 37 U/ml) increased from 4.13-fold to 17.71-fold (both P = 0.0055) compared with the patients who had no risk factors. CONCLUSION: Positive ctDNA predicts poor survival for patients with BR-PC who undergo NAC followed by pancreatectomy.

Clinical and biological determinants of circulating tumor DNA detection and prognostication using a next-generation sequencing panel assay.

Circulating tumor DNA (ctDNA) is utilized for molecular profiling of cancers, and is under investigation for a growing number of applications based on the assumption that ctDNA levels faithfully reflect disease burden. Our objective was to investigate whether patient and tumor characteristics may impact ctDNA detection or levels and the prognostic significance of ctDNA levels or mutations. We performed a retrospective cohort analysis of a comprehensively annotated cohort of 561 patients at a National Cancer Institute-designated comprehensive cancer center with advanced solid cancers who underwent ctDNA testing using a commercial targeted next-generation sequencing assay. ctDNA detection in advanced cancers was associated with older age, non-obese body mass index, and diabetes, but not with tumor diameter, volume, lesion number, or other pathological features. Regression models indicate that no more than 14.3% of the variance in ctDNA levels between patients was explained by known clinical factors and disease burden. Even after adjusting for established prognostic factors and tumor burden, ctDNA levels were associated with worse survival among patients without prior systemic therapy, while ctDNA mutations were associated with survival among patients who previously received systemic treatment. These findings uncover clinical factors that affect ctDNA detection in patients with advanced cancers and challenge the convention that ctDNA is a surrogate for tumor burden. Our study also indicates that the prognostic value of ctDNA levels and mutations are independent of tumor burden and dependent on treatment context.

Eradicating micrometastases with immune checkpoint blockade: Strike while the iron is hot.

Immune checkpoint blockade (ICB) is transforming treatment for many cancers. While ICB alone initially demonstrated efficacy in patients with metastatic melanoma, it has expanded to other types and to earlier-stage cancers. We describe ICB history, mechanisms underlying variation in response, and how ICB is being integrated into adjuvant and neoadjuvant treatment approaches.

Longitudinal assessment of B-RAF V595E levels in the peripheral cell-free tumor DNA of a 10-year-old spayed female Korean Jindo dog with unresectable metastatic urethral transitional cell carcinoma for monitoring the treatment response to a RAF inhibitor (sorafenib).

Transitional cell carcinoma (TCC) is the most common malignant tumor of the canine urinary tract. In this case study, a dog with metastatic urethral TCC was treated with sorafenib. The tumor expression levels of receptor tyrosine kinase genes, including VEGFR-1, VEGFR-2, PDGFR-α, PDGFR-ß, ALK, EGFR, ErbB2, and B-RAF, were analyzed. VEGFR was overexpressed in tumor tissues compared to the normal tissues. Considering the high frequency of B-RAF mutation in canine urological tumors, the B-RAF gene was examined, and the B-RAF V595E mutation was detected in the tumor tissue. Therefore, the antitumor effect of sorafenib, a multi-tyrosine kinase inhibitor, on unresectable metastatic urethral TCC characterized by B-RAF V595E was evaluated and circulating cell-free tumor DNA (ctDNA) was assessed for monitoring the treatment response. After the initiation of oral sorafenib therapy (4 mg/kg/day escalated to 10 mg/kg/day), the dysuria was alleviated gradually, and the patient remained stable for 3 months. During that treatment period, the patient showed various levels of changes associated with B-RAF V595E mutation in ctDNA as evident from longitudinal plasma samples after initiation of sorafenib therapy. The findings of this study suggest that ctDNA may serve as a useful non-invasive tool for monitoring the treatment response to anticancer drugs.

A supersensitive silicon nanowire array biosensor for quantitating tumor marker ctDNA.

Cancer has become one of the major diseases threatening human health and life. Circulating tumor DNA (ctDNA) testing, as a practical liquid biopsy technique, is a promising method for cancer diagnosis, targeted therapy and prognosis. Here, for the first time, a field effect transistor (FET) biosensor based on uniformly sized high-response silicon nanowire (SiNW) array was studied for real-time, label-free, super-sensitive detection of PIK3CA E542K ctDNA. High-response 120-SiNWs array was fabricated on a (111) silicon-on-insulator (SOI) by the complementary metal oxide semiconductor (CMOS)-compatible microfabrication technology. To detecting ctDNA, we modified the DNA probe on the SiNWs array through silanization. The experimental results demonstrated that the as-fabricated biosensor had significant superiority in ctDNA detection, which achieved ultralow detection limit of 10 aM and had a good linearity under the ctDNA concentration range from 0.1 fM to 100 pM. This biosensor can recognize complementary target ctDNA from one/two/full-base mismatched DNA with high selectivity. Furthermore, the fabricated SiNW-array FET biosensor successfully detected target ctDNA in human serum samples, indicating a good potential in clinical applications in the future.

Early plasma circulating tumor DNA (ctDNA) changes predict response to first-line pembrolizumab-based therapy in non-small cell lung cancer (NSCLC).

BACKGROUND: Currently available biomarkers are imperfect in their ability to predict responses to the multiple first-line treatment options available for patients with advanced non-small cell lung cancer (NSCLC). Having an early pharmacodynamic marker of treatment resistance may help redirect patients onto more effective alternative therapies. We sought to determine if changes in circulating tumor DNA (ctDNA) levels after initiation of first-line pembrolizumab±chemotherapy in NSCLC would enable early prediction of response prior to radiological assessment. METHODS: Plasma collected from patients with advanced NSCLC prior to and serially after starting first-line pembrolizumab±platinum doublet chemotherapy was analyzed by next-generation sequencing using enhanced tagged-amplicon sequencing of hotspots and coding regions from 36 genes. Early change in ctDNA allele fraction (AF) was correlated with radiographic responses and long-term clinical outcomes. RESULTS: Among 62 patients who received first-line pembrolizumab±platinum/pemetrexed and underwent ctDNA assessment, 45 had detectable ctDNA alterations at baseline. The median change in AF at the first follow-up (at a median of 21 days after treatment initiation) was -90.1% (range -100% to +65%) among patients who subsequently had a radiologic response (n=18), -19.9% (range: -100% to +1884%) among stable disease cases (n=15), and +28.8% (range: -100% to +410%) among progressive disease cases (n=12); p=0.003. In addition, there was a significant correlation between the percent change in ctDNA at the first follow-up and the percent change in tumor target lesions from baseline (R=0.66, p<0.001). AF decrease between the pretreatment and first on-treatment blood draw was associated with significantly higher response rate (60.7% vs 5.8%, p=0.0003), and significantly longer median progression-free survival (8.3 vs 3.4 months, HR: 0.29 (95% CI: 0.14 to 0.60), p=0.0007) and median overall survival (26.2 vs 13.2 months, HR: 0.34 (95% CI: 0.15 to 0.75), p=0.008) compared with cases with an AF increase. CONCLUSION: In patients with advanced NSCLC, rapid decreases in ctDNA prior to radiological assessment correlated with clinical benefit. These results suggest a potential role for ctDNA as an early pharmacodynamic biomarker of response or resistance to immunotherapies.

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.

Exosome-based liquid biopsies in cancer: opportunities and challenges.

Liquid biopsy in cancer has gained momentum in clinical research and is experiencing a boom for a variety of applications. There are significant efforts to utilize liquid biopsies in cancer for early detection and treatment stratification, as well as residual disease and recurrence monitoring. Although most efforts have used circulating tumor cells and circulating tumor DNA for this purpose, exosomes and other extracellular vesicles have emerged as a platform with potentially broader and complementary applications. Exosomes/extracellular vesicles are small vesicles released by cells, including cancer cells, into the surrounding biofluids. These exosomes contain tumor-derived materials such as DNA, RNA, protein, lipid, sugar structures, and metabolites. In addition, exosomes carry molecules on their surface that provides clues regarding their origin, making it possible to sort vesicle types and enrich signatures from tissue-specific origins. Exosomes are part of the intercellular communication system and cancer cells frequently use them as biological messengers to benefit their growth. Since exosomes are part of the disease process, they have become of tremendous interest in biomarker research. Exosomes are remarkably stable in biofluids, such as plasma and urine, and can be isolated for clinical evaluation even in the early stages of the disease. Exosome-based biomarkers have quickly become adopted in the clinical arena and the first exosome RNA-based prostate cancer test has already helped >50 000 patients in their decision process and is now included in the National Comprehensive Cancer Network guidelines for early prostate cancer detection. This review will discuss the advantages and challenges of exosome-based liquid biopsies for tumor biomarkers and clinical implementation in the context of circulating tumor DNA and circulating tumor cells.

Retrospective analysis of real-world data to determine clinical outcomes of patients with advanced non-small cell lung cancer following cell-free circulating tumor DNA genomic profiling.

OBJECTIVES: Liquid biopsy and comprehensive genomic profiling (CGP) of circulating tumor DNA (ctDNA) are increasingly used for detection of targetable genomic alterations (GA) in non-small cell lung cancer (NSCLC). To examine the clinical outcomes for patients following CGP using liquid biopsy versus tissue biopsy, receipt of matched targeted therapy post-CGP and associated outcomes were evaluated in the real-world setting. METHODS: 6491 patients with NSCLC and liquid biopsy (N = 937 tests) and/or tissue (N = 5582 tests) CGP were included in a de-identified commercial clinico-genomic database. Targetable GAs included National Comprehensive Cancer Network NSCLC guideline biomarkers. Clinical characteristics, real-world progression, and real-world response (rwR) were obtained via technology-enabled abstraction of clinician notes and radiology/pathology reports. RESULTS: At the time of liquid biopsy CGP, 53% (496/937) of patients were documented to have received ≥1 line of prior therapy (tissue CGP: 13%, 735/5582). 90% (832/928) of liquid biopsy cases had evidence of ctDNA. A targetable GA was detected in 20% (188/937) of liquid biopsy and 22% (1215/5582) of tissue CGP cases. Use of matched targeted therapy overall was similar post-liquid biopsy or post-tissue CGP but varied considerably across emerging (25%, 79/317) versus standard of care (SOC) (74%, 475/640) GA. Real-world-progression free survival for patients receiving SOC first line matched targeted therapy administered following liquid biopsy (n = 33) and tissue (n = 229) CGP were similar (13.8 vs 10.6 months; aHR = 0.68 [0.36-1.26]). Among patients evaluated for rwR, overall response rate (partial/complete response) to matched targeted therapy post-liquid biopsy CGP was 75% (39/52) versus 66% post-tissue CGP (254/385, P = 0.51). CONCLUSION: Retrospective analysis of real-world clinico-genomic data demonstrated that clinical outcomes on matched targeted therapy were similar following liquid biopsy and tissue CGP in NSCLC, which suggests routine clinical use of liquid biopsy CGP can reliably guide therapy selection.

Sensitive and selective ctDNA detection based on functionalized black phosphorus nanosheets.

Circulating tumor DNA (ctDNA) identification is one of the most meaningful approaches towards early cancer diagnosis. However, effective and practical methods for analyzing this emerging class of biomarkers are still lacking. In this work, a biosensor based on nitrophenyl functionalized black phosphorus nanosheets (NP-BPs) is fabricated for sensitive and selective detection of ctDNA. In this work, a nitrophenyl functionalized black phosphorus nanosheets (NP-BPs) biosensor is fabricated for sensitive and selective detection of ctDNA. Due to the successful nitrophenyl functionalization, the NP-BPs biosensor shows higher quenching efficiency and stronger affinity towards single-stranded DNA (ssDNA), as compared with double-stranded DNA (dsDNA). Therefore, the NP-BPs biosensor exhibits 5.4-fold fluorescence enhancement when dye-labelled ssDNA probe forms dsDNA in the presence of its specific ctDNA target. This biosensor exhibits a detection limit of 50 fM and a wide linear detection range of 50 fM-80 pM, provides reliable readout in a short time (15 min). Moreover, the NP-BPs-based biosensor could be applied to discriminate single nucleotide polymorphisms in clinical serum samples. It is envisioned that the NP-BPs-based sensing platform has great potentials in early cancer diagnosis and monitoring cancer progression.