Use Of ctDNA Research Articles

The "oncological trace": circulating tumor DNA in uveal melanomas

Cell-free DNA (cfDNA) and the tumor DNA it contains can be detected in various body fluids and can be obtained in aminimally invasive manner using a liquid biopsy. The fragmented cell-free tumor DNA (ctDNA) serves as amarker for the presence of tumor cells in the body and its analysis enables genetic tumor characteristics to be determined. For some nonocular tumors ctDNA is already approved as apredictive or prognostic marker. This literature review article describes examples of the use of ctDNA as abiomarker in nonocular tumors and the current status of ctDNA analysis in cases of uveal melanomas. For this purpose, aselective literature search was carried out via PubMed. Uveal melanomas are nowadays usually treated by eye-preserving therapy. In these cases, there is usually no tumor tissue available for further diagnostic testing. Alternatively, molecular characteristics of the tumor can be determined by the genetic analysis of ctDNA. In uveal melanomas the presence of ctDNA in the plasma at the time of the primary diagnosis is controversial; however, an increase in the amount of ctDNA, which can be used to investigate diagnostically and prognostically relevant genetic changes, was detected during irradiation therapy of the primary tumor in some patients. In the later course of the disease, the amount of ctDNA in the plasma is asuitable marker for metastatic progression. In some cases, an increase in ctDNA levels could be recognized several months before the clinical detection of metastases. The analysis of cfDNA in patients with a uveal melanoma is apromising and minimally invasive method for obtaining information about the tumor or the course of the disease. It is currently being investigated which patients could benefit from it in the future. Several issues related to standardization and technical validation must be addressed for its routine clinical application.

Novel Combinations of Immunotherapies or DNA Damage Repair Inhibitors in Platinum-Refractory Extensive-Stage Small Cell Lung Cancer: The Phase II BALTIC Study.

The phase II, multiarm, signal-searching BALTIC study (NCT02937818) assessed novel treatment combinations for platinum-refractory/resistant extensive-stage small cell lung cancer (ES-SCLC). Patients with ES-SCLC with progressive disease during or within 90 days of completing first-line platinum-based chemotherapy received one of three regimens: durvalumab plus tremelimumab followed by durvalumab monotherapy (arm A), adavosertib plus carboplatin (arm B), or ceralasertib plus olaparib (arm C). The primary endpoint was the objective response rate. Prespecified exploratory biomarker analyses were conducted in arms A and C. In arm A (n = 41), arm B (n = 10), and arm C (n = 21), the confirmed objective response rates were 7.3%, 0%, and 4.8%, respectively. Safety profiles in all arms were consistent with those of the individual drugs. In arm A, patients with PD-L1 expression (tumor cells or immune cells) ≥1% seemed to have a greater likelihood of achieving disease control with durvalumab plus tremelimumab than those with PD-L1 (tumor cells and immune cells) <1%, and lower baseline ctDNA and reduction in the on-treatment ctDNA level were both associated with longer overall survival. Among patients treated with ceralasertib plus olaparib in arm C, specific immune response-relevant circulating chemokines and cytokines were identified as early biomarkers of survival and pharmacodynamic biomarkers. In BALTIC, all combination regimens demonstrated tolerable safety profiles, but antitumor activity was limited in refractory/resistant ES-SCLC. Among patients treated with durvalumab plus tremelimumab, an association of on-treatment reduction in ctDNA with longer overall survival suggests the potential use of ctDNA as a surrogate of treatment response, warranting further investigation.

SEOM-GEMCAD-TTD clinical guidelines for the adjuvant treatment of colon cancer (2023)

Colorectal cancer (CRC) has a 5-year overall survival rate of over 60%. The decrease in the rate of metastatic disease is due to screening programs and the population’s awareness of healthy lifestyle. Similarly, advancements in surgical methods and the use of adjuvant chemotherapy have contributed to a decrease in the recurrence of resected disease. Before evaluating a patient’s treatment, it is recommended to be discussed in a multidisciplinary tumor board. In stage II tumors, the pathologic characteristics of poor prognosis must be known (T4, number of lymph nodes analyzed less than 12, lymphovascular or perineural invasion, obstruction or perforation, poor histologic grade, presence of tumor budding) and it is mandatory to determine the MSI/MMR status for avoiding administering fluoropyridimidines in monotherapy to patients with MSI-H/dMMR tumors. In stage III tumors, the standard treatment consists of a combination of fluoropyrimidine (oral or intravenous) with oxaliplatin for 6 months although the administration of CAPOX can be considered for 3 months in low-risk tumors. Neoadjuvant treatment is not consolidated yet although immunotherapy is achieving very good preliminary results in MSI-H patients. The use of ctDNA to define the treatment and monitoring of resected tumors is only recommended within studies. These guidelines are intended to help decision-making to offer the best management of patients with non-metastatic colon cancer.

Plasma circulating tumor DNA in patients with cutaneous squamous cell carcinoma: Initial experience.

e15034 Background: Circulating tumor DNA (ctDNA) has emerged as a potential noninvasive biomarker to assess tumor burden throughout cancer treatment and to aid in clinical decision-making. However, data on the use of ctDNA in cutaneous squamous cell carcinoma (cSCC) is currently lacking. In this study, we report our first experience with ctDNA in patients with cSCC. Methods: In this IRB-approved study at a tertiary care center, an initial cohort of patients with intermediate to high-risk cSCC had tissue and plasma sent for ctDNA analysis using Natera®’s proprietary bioinformatics pipeline. This cohort included 21 patients treated from 2023 to the present. Initial tissue samples were obtained through biopsy (i.e., excisional, punch, or shave), Mohs surgery, or surgical resection. Some patients had additional plasma sample(s) drawn later during or after the treatment course. Patients either received a “positive,” “positive below analytical range,” or “negative” result or had ‘insufficient sample’ to receive a result based on Natera®’s analysis. All patients were treated curatively with surgical resection with or without adjuvant radiation as per the standard of care. The assessment of gross disease was determined based on whether the patient had disease present on imaging or physical exam at the time of the plasma draw. A comparison of ctDNA results and the presence of gross disease was done using Fisher’s exact test. Results: Of the samples submitted for Natera® ctDNA analysis, 18/21 had sufficient tissue for analysis of tumor DNA. All 3 tumors with insufficient tissue were from biopsies (6/9 sufficient), while 12/12 of those from Mohs or surgical resection had sufficient tissue. The average tumor volume in these patients with insufficient samples for tumor analysis was relatively low (0.35 cm3) compared to those that resulted (17-30 cm3). 7/9 (78%) patients with gross disease had a positive ctDNA result, which was significantly greater than those with no gross disease (1/9 patients, 11%) (p = 0.004). Three patients in our cohort with an initially positive ctDNA result had multiple plasma draws, with all having a later draw demonstrating a negative ctDNA result after having surgery and/or radiation. Conclusions: Circulating tumor DNA is a reliable marker for patients with cSCC with a high tumor burden and is feasible in those with adequate tissue. However, in patients where it is only possible to obtain a small volume of tumor tissue and/or low tumor burden, ctDNA may be a less reliable biomarker. [Table: see text]

Abstract PO2-15-02: Personalized circulating tumor DNA (ctDNA) monitoring can early identify disease progression and predict prognosis in patients with breast cancer undergoing neoadjuvant therapy

Abstract Background: Circulating tumor DNA (ctDNA) analysis offers a non-invasive method to assess tumor burden during treatment. Although some data have been reported on the use of ctDNA in neoadjuvant therapy (NAT) for breast cancer (BC), there is a lack of data on neoadjuvant efficacy and prognosis in China specifically using tumor-informed personalized ctDNA monitoring panel. Methods: We performed personalized ctDNA analyses at different time of NAT (before, during, and after) in 19 patients with Stage IIA-IIIB BC. WES was conducted on tumor tissues, and single nucleotide variants (SNVs) (20-40) were selected for each patient to ensure accurate and sensitive detection of individual ctDNA(Shanghai OrigiMed Co., Ltd.). Results: A total of 19 BC patients, 6 HER2-negative and 13 HER2-positive, were enrolled at the Breast Center, Fourth Hospital of Hebei Medical University (China) from June 2022 to May 2023. The median age of the patients was 53 (min-max: 28-64) years old. Through WES, it was discovered that 78.5% (3377/4303) of the mutated genes were unique to each patient. Additionally, 96.1% (637/663) of the selected tumor-informed SNVs were VUS variants. These findings suggest that tumor-informed ctDNA monitoring is more effective than panel-based ctDNA monitoring in BC. Among the patients, 84% (16/19) completed baseline blood collection, 63% (12/19) completed blood collection after NAT and 42% (8/12) patients completed blood collection after the surgery. The baseline positivity rate was 100%, and the baseline ctDNA variant allele frequency was significantly associated with T stage and N stage (both p &amp;lt; 0.01). This suggests that designing a panel based on puncture samples is feasible for ctDNA analysis. The detection of ctDNA before surgery after NAT correlated with the postoperative ctDNA status. Patients with persistently negative ctDNA during NAT were associated with pathologic complete response (pCR), although the difference was not statistically significant due to the small sample size (n=7). In 84% of patients, dynamic changes in ctDNA aligned with imaging findings, indicating a correlation between ctDNA and disease progression. A 56-year-old patient with HER2-negative stage IIIC BC had persistent ctDNA positivity during NAT. Imaging evaluation showed disease progression, with ctDNA allele frequency increasing 18 days before detection on imaging. After surgical tumor removal, the pathology assessment revealed a change in HER2 status from negative to positive. The patient received adjuvant chemotherapy combined with HER2-targeted therapy, resulting in a transition from positive to negative ctDNA status. The disease has remained stable for nearly 9 months. A 29-year-old patient with HER2-positive stage IIIA BC underwent NAT for 8 cycles. Due to drug intolerance, the treatment was interrupted multiple times during the first 4 cycles, and ctDNA remained positive. After modifying the treatment regimen in the 5th cycle, ctDNA became negative until the patient underwent surgery. The postoperative pathology evaluation revealed a pCR. Conclusions: Personalized ctDNA monitoring is more effective than panel-based ctDNA (a predefined set of cancer-associated genes) monitoring in BC. The status of ctDNA before and after surgery following NAT may be correlated, suggesting that patients with positive ctDNA before surgery may benefit from intensive therapy. More importantly, dynamic changes in ctDNA closely align with radiological findings, enabling early detection of disease progression and guiding treatment modifications. Citation Format: Yunjiang Liu, Chao Shi, Xiangmei Zhang, Xiaofei Ren, Shang Wu, Yaxian Wang, Yue Che, Zanmei Xu, Fei Pang. Personalized circulating tumor DNA (ctDNA) monitoring can early identify disease progression and predict prognosis in patients with breast cancer undergoing neoadjuvant therapy [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-15-02.

Advancing Evidence Generation for Circulating Tumor DNA: Lessons Learned from A Multi-Assay Study of Baseline Circulating Tumor DNA Levels across Cancer Types and Stages.

Circulating tumor DNA (ctDNA) holds promise as a biomarker for predicting clinical responses to therapy in solid tumors, and multiple ctDNA assays are in development. However, the heterogeneity in ctDNA levels prior to treatment (baseline) across different cancer types and stages and across ctDNA assays has not been widely studied. Friends of Cancer Research formed a collaboration across multiple commercial ctDNA assay developers to assess baseline ctDNA levels across five cancer types in early- and late-stage disease. This retrospective study included eight commercial ctDNA assay developers providing summary-level de-identified data for patients with non-small cell lung cancer (NSCLC), bladder, breast, prostate, and head and neck squamous cell carcinoma following a common analysis protocol. Baseline ctDNA levels across late-stage cancer types were similarly detected, highlighting the potential use of ctDNA as a biomarker in these cancer types. Variability was observed in ctDNA levels across assays in early-stage NSCLC, indicative of the contribution of assay analytical performance and methodology on variability. We identified key data elements, including assay characteristics and clinicopathological metadata, that need to be standardized for future meta-analyses across multiple assays. This work facilitates evidence generation opportunities to support the use of ctDNA as a biomarker for clinical response.

Abstract 976: Detection of circulating tumor DNA predicts survival in advanced HCC patients treated with personalized therapeutic DNA cancer vaccine in combination with immune checkpoint blockade

Abstract Circulating tumor DNA (ctDNA) has enabled the non-invasive monitoring of molecular residual disease (MRD) which reflects therapeutic response/resistance prior to conventional imaging approaches. However, little is known about the applications of ctDNA in the neoantigen-targeted personalized cancer vaccine setting, potentially due to the limited sensitivity of current ctDNA assays. NeXT Personal®, an ultra-sensitive tumor-informed ctDNA assay was used to longitudinally track ctDNA in advanced hepatocellular carcinoma (HCC) patients treated with GNOS-PV02 (a personalized therapeutic DNA cancer vaccine) in combination with pembrolizumab. Advanced unresectable or metastatic HCC patients that progressed on, or were intolerant to, first-line TKI therapy were enrolled into the Phase 1b/2a GT-30 study [NCT04251117]. Whole exome/transcriptome tumor sequencing was used for the design of GNOS-PV02. Patients were treated with GNOS-PV02 (1mg; Q3W x 4, Q9W) and plasmid-encoded IL-12 (0.3mg; Q3W x 4, Q9W) in combination with pembrolizumab (200mg; Q3W). Clinical Response was evaluated by RECIST 1.1 at baseline and Q9W. The ctDNA analysis and tracking for progression was performed as an exploratory objective. Over 200 prospective baseline and on-treatment plasma samples from 31 patients were collected and analyzed using NeXT Personal. WGS was performed to identify up to ~1,800 selected tumor variants to create a personalized panel for MRD detection. NeXT Personal has been analytically validated to detection thresholds down to 1-3 parts per million (PPM) of ctDNA with &amp;gt;99.95% specificity. ctDNA was detected in 152 of 207 plasma samples with a dynamic range of 1.76 - 166,968 PPM. The limit of ctDNA detection ranged down to 1.05 PPM. 96% (24/25) of patients were baseline ctDNA+. The percentage change of ctDNA relative to baseline at week 9 (C4D1) significantly correlated with best overall response (CR/PR/SD vs. PD: p = 0.0076). The ctDNA change from baseline to week 9 was predictive of OS (P=0.008), with 31.2% 2-yr OS (95% CI: 13.2 - 73.7%) for molecular non-responders vs 100% 2-yr OS (95%CI: 100 - 100%) for molecular responders. In addition, the ctDNA levels at week 9 were predictive of best overall response (P = 0.017). ctDNA burden at week 9 was significantly correlated with overall survival (HR = 5.46, 95%CI: 1.79 - 16.65; P=0.003; C-index = 0.886). ctDNA clearance was observed in all 3 CR patients with a lead time of 483, 126 and 105 days compared with MRI. This ultra-sensitive ctDNA assay shows significant association between ctDNA change and clinical response and survival, and can be used to accurately predict clinical outcome. The convenience of non-invasive liquid biopsy and rapid availability of data could enable the use of ctDNA to allow real-time monitoring of personalized cancer immunotherapy. Citation Format: Jian Yan, Bailiang Li, Josette Northcott, Charles W. Abbott, Rachel M. Pyke, Renzo Perales-Linares, Neil Cooch, Sarah Rochestie, Joann Peters, Edward J. Gane, Mark Yarchoan, Thomas U. Marron, Sean M. Boyle, Ildiko Csiki, Richard Chen, Niranjan Y. Sardesai. Detection of circulating tumor DNA predicts survival in advanced HCC patients treated with personalized therapeutic DNA cancer vaccine in combination with immune checkpoint blockade [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 976.

Circulating tumor DNA (ctDNA) as a biomarker for lung cancer: Early detection, monitoring and therapy prediction.

Circulating tumor DNA (ctDNA), i.e., DNA shed from tumor cells into the bloodstream, is emerging as one of the most useful plasma biomarkers in patients with multiple types of cancer, including patients with non-small cell lung cancer (NSCLC). Indeed, NSCLC was the first malignancy in which measurement of ctDNA was approved for clinical use, i.e., mutational testing of EGFR for predicting response to EGFR tyrosine kinase inhibitors in patients with advanced disease. Although historically the gold standard method for EGFR mutational analysis required tumor tissue, the use of ctDNA is more convenient and safer for patients, results in a faster turn-around-time for return of results, provides a more complete representation of genetic alteration in heterogeneous tumors and is less costly to perform. Emerging uses of ctDNA in patients with lung or suspected lung cancer include screening for early disease, surveillance following initial treatment and monitoring response to therapy in metastatic disease. For evaluating therapy response, ctDNA appears to be especially useful in patients receiving targeted therapies against driver oncogenes or immunotherapy. Further work should not only validate these emerging findings but also aim to optimize and standardize ctDNA assays.

Circulating Tumor DNA (ctDNA) and Its Role in Gynecologic Malignancies.

Circulating tumor DNA (ctDNA) refers to small fragments of DNA released into the bloodstream by cancer cells. It is obtained through "liquid biopsy;" which most commonly refers to plasma or blood samples, but can be obtained from a number of bodily fluids including ascitic fluid, saliva, and even urine and stool. ctDNA is detected via polymerase chain reaction (PCR) or next-generation sequencing (NGS). The DNA from these samples is analyzed for the detection of point mutations, copy-number alterations, gene fusion, and DNA methylation. These results have the potential for use in cancer diagnosis, determining prognosis, targeting gene-specific therapies, and monitoring for/predicting disease recurrence and response to treatment. ctDNA offers an alternative to tissue biopsy; it is less invasive and can be monitored serially over time without multiple procedures. Moreover it may have the ability to detect disease recurrence or predict behavior in a way that solid tissue biopsies, tumor marker surveillance, and imaging cannot. Recent explosion in interest in ctDNA shows promising developments for widespread adoption of these techniques in cancer care. However, the use of ctDNA in diagnosis and treatment of gynecologic malignancies is currently limited, compared to adoption in other solid-organ tumors such as breast and colorectal cancers. Compared to other cancer types, there appear to be fewer comprehensive studies and clinical validations specifically focusing on the use of ctDNA in gynecologic cancers. More research is needed in this area to advance the potential for use of ctDNA in ovarian, endometrial, and cervical cancers before this can be routinely adopted to improve care for patients with gynecologic malignancies.

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

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

Use of tumor-informed ctDNA across gastrointestinal cancers.

758 Background: In colorectal cancer (CRC), the use of ctDNA for the purpose of early recurrence detection and prognostication is established, and multiple studies are testing its utility for guiding adjuvant therapy decisions. Tumor informed testing can be performed in clinical situations where adequate tissue is available for next-generation sequencing (NGS). Increasingly, ctDNA testing is being used clinically for colorectal cancer patients and other gastrointestinal (GI) cancers when there is an appropriate clinical scenario and adequate tumor tissue is available for sequencing. Methods: We identified GI cancer patients treated at our institution where Signatera (Natera) testing was ordered and performed between 2020 – 2023. We included all patients for whom testing was ordered. Then, among patients with any result further analyzed results by disease type, stage, and results. We examined clinical rationale for testing and whether results informed subsequent decisions. Results: A total of 99 GI cancer patients for whom ctDNA testing was ordered were identified. 80 patients had at least 1 ctDNA result including 68 colorectal patients and 12 other GI cancers (anal, bile duct, esophagogastric, pancreatic, and small bowel). Among patients with measurable ctDNA, at the most recent testing timepoint 16 had levels that met criteria for positive detection, while 64 were undetectable. Most commonly, testing was ordered in stage II/III CRC patients for post-operative surveillance. Other clinical use scenarios included 1) surveillance/treatment monitoring in oligometastatic CRC, 2) surveillance in non-metastatic esophagogastric cancer, 3) treatment monitoring in MSI-H/immunotherapy sensitive GI cancers. For at least 18 patients, results were a factor in shared clinical decision making between patients and providers. Conclusions: We found ctDNA monitoring is most commonly used in the adjuvant setting for CRC patients which is best supported by existing studies. Our data demonstrates that tumor informed testing can be successful in other GI cancers for both surveillance and therapy monitoring. Given the broad and rapid adoption of this technology, there needs to be continued efforts for both prospective validation studies and retrospective real world studies to guide clinical practice.

Role of circulating tumor DNA in metastatic appendiceal neoplasms: A systematic review.

757 Background: Circulating tumor DNA (ctDNA), tumor DNA fragments detected in blood sourced from primary malignancy, is an emerging non-invasive tool in oncology for screening, diagnosis, and surveillance. Here, we analyze its utility in patients with metastatic appendiceal neoplasms. Methods: Following PRISMA guidelines, PubMed, Cochrane, and Clinicaltrials.gov were searched for ‘Appendiceal Neoplasms’ AND ‘Circulating Tumor DNA’. Four original studies reporting the role of ctDNA in appendiceal cancer were included after screening 195 articles. Results: A total of 196 patients were included in the review. (Table) The total number of collected samples was 209 and 41% were tested positive for ctDNA. Singh et al. 2023 reported eight stage IV appendiceal cancer patients with the median age of 64.5 (45-75) years. 37.5% were tested positive for ctDNA while 37.5% had undetectable ctDNA despite having residual peritoneal disease and 25% had insufficient DNA from tumor specimen. López-Rojo et al. 2020 reported 50% ctDNA positive rate. All included patients had KRAS mutation and received hyperthermic intraperitoneal chemotherapy (HIPEC). On 36.5 months follow-up all the patients were alive but one out of two ctDNA positive patients had a relapse at 39 months follow-up. Kothary et al. 2022 reported 51% ctDNA positivity and 11% had longitudinal ctDNA measurements available which correlated well with their disease course. Zeineddine et al. 2023 collected 160 blood samples from 147 patients. Of 75% with radiographically metastatic disease, 38% had positive ctDNA while out of 25% with no radiographically metastatic disease, 38% had positive ctDNA. The overall survival and progression free survival for ctDNA positive patients was 46.2 months and 60 months, respectively, versus not reached for ctDNA negative patients. When stratified according to tumor grade, the ctDNA detection rate was 22% for well-differentiated, 39% for moderately differentiated, and 49% for poorly differentiated tumors. Conclusions: The use of ctDNA in metastatic appendiceal tumor is not widespread and detection rates are heterogenous. It was observed more in poorly differentiated appendiceal cancers but further studies are needed to evaluate its utility in clinical practice. [Table: see text]

Association of pathologic nodal status with minimal residual disease after neoadjuvant treatment and resection of locally advanced rectal cancer.

205 Background: Studies have shown that minimal residual disease (MRD) identified by detection of circulating tumor DNA (ctDNA) is associated with recurrence after surgical resection of colorectal cancer. Though multiple trials are evaluating the use of ctDNA to guide adjuvant therapy, data on the utility of ctDNA after neoadjuvant therapy is limited. In this study, we evaluated the associations between ctDNA and recurrence after neoadjuvant treatment and resection of rectal cancer (LARC). Methods: Consecutive patients with primary rectal cancer treated with neoadjuvant systemic therapy and/or chemoradiotherapy followed by resection between 12/2020-4/2023 were identified. Patients were tested for ctDNA via the MD Anderson INTERCEPT platform using a high-sensitivity patient informed assay. Patients with metastases or a first ctDNA test more than 3 months after resection were excluded. MRI-determined stage, extramural vascular invasion (mrEMVI), pelvic sidewall adenopathy (PSW), pathologic lymphovascular invasion (LVI), perineural invasion (PNI) and tumor regression grade (TRG) were collected. Associations between these factors and ctDNA status were analyzed with Fischer’s exact test. Recurrence free survival (RFS) was analyzed with the log-rank test. Results: Sixty-seven patients (3 treated with chemoradiotherapy alone, 15 with systemic therapy alone and 49 with total neoadjuvant therapy) were identified. Positive ctDNA was identified in 6 (8.9%) within 3 months after resection, all of whom received total neoadjuvant therapy, and 3/6 recurred within 12 months. Clinical T status (p=0.146), N status (p=0.842), mrEMVI (p=0.475) and PSW (p=0.318) were not associated with MRD. TRG was not associated with MRD (TRG0-1: 4% vs TRG2-3: 11.3%, p=0.547). Pathologic N status was associated with MRD (ypN0: 4.4% vs ypN+: 18%, p=0.049). MRD was associated with a median RFS of 3.2 months (HR 39, 95% CI: 4.1-380, p=0.0015). 1-year RFS was 98% for patients without MRD. Conclusions: Minimal residual disease after multi-modality treatment of LARC is associated with early metastatic recurrence. The patient informed MRD assay appears both sensitive and specific for detection of relapse. Advanced clinical stage and high-risk radiologic features were not associated with MRD, while post-treatment pathologic N status was. Given the high relapse rate for MRD+ patients, MRD detection after resection warrants additional investigation for metastases and/or enrollment on MRD treatment clinical trial. Methods to predict MRD prior to resection are urgently needed.

Perioperative Use of ctDNA to Guide Treatment for Urothelial Carcinoma: TheFuture is Now.

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

Diagnostic peculiarities of lymphomas in the cervical region in children

Thisarticle discusses various aspects of pediatric lymphadenopathy, focusing on Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL). It outlines common etiologies, diagnostic techniques, and key characteristics of differ- ent lymphoma subtypes. HL is classified into classical HL (CHL) and nodular lymphocytic predominant HL (NLPHL), while NHL includes Burkitt lymphoma (BL), lymphoblastic lymphoma (LBL), diffuse large B-cell lymphoma (DLBCL), and anaplastic large cell lymphoma (ALCL). The text emphasizes the importance of accurate diagnosis through various tests, including imaging modalities such as positron emission tomography (PET) and computed tomography (CT). It also discusses the potential use of ctDNA as a prognostic marker and highlights genetic alterations contributing to lymphoma development. The relevance of these findings for pediatric patients and their impact on treatment strategies is emphasized throughout the text.

Circulating Tumor DNA (ctDNA) in Kidney Cancer: A Narrative Review

Circulating tumor DNA (ctDNA) has been investigated as a potential noninvasive biomarker for disease prognostication, monitoring, and treatment selection in various tumor types, including renal cell carcinoma (RCC). In this narrative review, we explore the current methods of ctDNA analysis and the use of ctDNA in both localized and metastatic RCC, focusing on plasma and urine samples. Additionally, we discuss several ongoing as well as upcoming clinical trials that incorporate ctDNA analyses into their study designs and outcomes. Despite the exciting potential of ctDNA in RCC, current assays still face significant limitations in sensitivity and detection limits.

Practical recommendations for using ctDNA in clinical decision making.

The continuous improvement in cancer care over the past decade has led to a gradual decrease in cancer-related deaths. This is largely attributed to improved treatment and disease management strategies. Early detection of recurrence using blood-based biomarkers such as circulating tumour DNA (ctDNA) is being increasingly used in clinical practice. Emerging real-world data shows the utility of ctDNA in detecting molecular residual disease and in treatment-response monitoring, helping clinicians to optimize treatment and surveillance strategies. Many studies have indicated ctDNA to be a sensitive and specific biomarker for recurrence. However, most of these studies are largely observational or anecdotal in nature, and peer-reviewed data regarding the use of ctDNA are mainly indication-specific. Here we provide general recommendations on the clinical utility of ctDNA and how to interpret ctDNA analysis in different treatment settings, especially in patients with solid tumours. Specifically, we provide an understanding around the implications, strengths and limitations of this novel biomarker and how to best apply the results in clinical practice.

Postoperative circulating tumor DNA detection and CBLB mutations are prognostic biomarkers for gastric cancer

BackgroundSeveral studies have demonstrated that circulating tumor DNA (ctDNA) can be used to predict the postoperative recurrence of several cancers. However, there are few studies on the use of ctDNA as a prognosis tool for gastric cancer (GC) patients.ObjectiveThis study aims to determine whether ctDNA could be used as a prognostic biomarker in GC patients through multigene-panel sequencing.MethodsUsing next-generation sequencing (NGS) Multigene Panels, the mutational signatures associated with the prognosis of GC patients were identified. We calculated the survival probability with Kaplan–Meier and used the Log-rank test to compare survival curves between ctDNA-positive and ctDNA-negative groups. Potential application of radiology combined with tumor plasma biomarker analysis of ctDNA in GC patients was carried out.ResultsDisease progression is more likely in ctDNA-positive patients as characterized clinically by a generally higher T stage and a poorer therapeutic response (P < 0.05). ctDNA-positive patients also had worse overall-survival (OS: P = 0.203) and progression-free survival (PFS: P = 0.037). The combined analysis of ctDNA, radiological, and serum biomarkers in four patients indicated that ctDNA monitoring can be a good complement to radiological and plasma tumor markers for GC patients. Kaplan–Meier analysis using a cohort of GC patients in the TCGA database showed that patients with CBLB mutations had shorter OS and PFS than wild-type patients (OS: P = 0.0036; PFS: P = 0.0027).ConclusionsThis study confirmed the utility and feasibility of ctDNA in the prognosis monitoring of gastric cancer.

Assessment of genomic profiling in patients with colorectal cancer treated in community oncology practices.

e15538 Background: Comprehensive genomic profiling is becoming the standard of care for oncology, though actionable biomarkers remain the focus. The value of expansion from single gene tests to large, next-generation sequencing (NGS) based tests can be seen in the application of precision medicine. Additionally, circulating tumor DNA (ctDNA) is becoming a key area of testing during and post treatment. In this study, we explored genetic testing rates in colorectal cancer (CRC) patients (pts). Methods: Pts were identified from the iKnowMedSM EMR data over 4 years (2018-2022) from 113 community oncology practices. Pts were required to have either primary colon or rectal cancer, be at least 20 yrs old at diagnosis, and have at least 2 office visits. All stages of disease were included. Genomic data was assessed from two sources: abstracted data from charts and genomics reports from clinical labs. Genomic tests included detection of mutations for relevant biomarkers, including but not limited to BRAF, KRAS, NRAS, NTRK, microsatellite instability (MSI), and tumor mutational burden (TMB), and entry of germline biomarkers relevant to Lynch syndrome. The use of ctDNA was also evaluated. Results: A cohort of 41,980 pts with CRC was identified. Median age was 66 yrs, 62% white. Of these, 18,782 pts (45%) had biomarker testing performed. Genomic testing rates were observed to have increased by 61% across all stages of disease over the four-year time span. The highest rate of biomarker testing was performed in pts with stage IV disease at diagnosis, representing 21% (n = 9021). Testing results were most often available for BRAF (n = 17576), with nearly 16% of the cohort showing a mutation, 35% of those with the V600E mutation (n = 967). MSI was observed in 14%. Increasing use of ctDNA observed, and 350 pts had multiple genetic reports (3+). Of the pts with genetic information, 245 were enrolled in clinical trials. Conclusions: In this study, we observed the increase of genetic profiling of CRC pts over time. Additional research into the use of targeted therapies and outcomes will be performed. The exploratory regions of the NGS-based assays tested may also provide new potential targets as the database of combined clinical and genetic information grows.

17th International Conference on Malignant Lymphoma, Palazzo dei Congressi, Lugano, Switzerland, 13 - 17 June, 2023.

Background: Classical Hodgkin lymphoma (cHL), the most common lymphoma in young adults, is a disease of poorly understood heterogeneity. The need for enriching tumor cells before assaying has limited the granularity of its molecular sub-classification. Although the cure rates of patients with cHL have increased over time, new biomarkers are still needed for more precise treatment decision-making in this complex patient population. Patients with cHL frequently have significant amounts of circulating tumor DNA (ctDNA), suggesting an alternative approach for studying this enigmatic tumor. Methods: IOSI-EMA003 (NCT03280394) is a prospective, observational, multi-center study of adult patients with newly diagnosed cHL aiming at: (i) identifying subgroups of patients with phenotype- and outcome-associated molecular signatures; (ii) testing and validating baseline ctDNA load as a prognostic biomarker; (iii) testing if ctDNA can be used as biomarker for the early identification of chemoresistance. Blood samples were collected at staging and disease response assessment. PET scans were centrally and blindly reviewed. ctDNA was analyzed by using deep targeted and low pass whole genome sequencing to measure ctDNA load, capture mutations and profile ctDNA fragmentation patterns. Single-cell RNA sequencing has been used to deconvolute the composition of the tumor microenvironment. Results: A total of 215 patients were enrolled. Based on ctDNA fragmentation patterns reflecting chromatin accessibility in the regulatory region of germinal center (GC) B-cell genes, we segregated cHL into two previously unknown subgroups that we named SNCD (for sub-nucleosomal cfDNA) and NCD (for nucleosomal cfDNA). We hypothesized that SNCD cHL stems from a cell that is closer to the GC B-cell differentiation stage than NCD cHL. SNCD cHL and NCD cHL differed in many aspects, including activation induced cytidine deaminase (AID)-hypermutation profile, neoantigen load, immune editing mechanism and response to chemotherapy and checkpoint inhibitors. Clinically, SNCD cHL displayed less sensitivity to both chemotherapy and anti-PD1 antibodies. Immune editing of SNCD cHL points loss of MHC-I, recruitment of Treg and upregulation of LAG3 as prominent immune checkpoint. High load of pre-treatment ctDNA nominated high-risk patients more accurately than clinico-radiological features. In addition, persistence of residual 18FDG avid lesions along with measurable ctDNA after two chemotherapy courses was a better proof of chemoresistance than the sole persistence of residual 18FDG avid lesions. Also, persistence of measurable ctDNA after the end of therapy invariably predicted progression. Conclusions: Collectively, our results provide a roadmap for cHL subtyping and for the clinical use of ctDNA as a biomarker to aid risk stratification and guide treatment decisions in a more personalized approach. Encore Abstract - previously submitted to ASCO 2023 The research was funded by: Research Advisory Board of the Ente Ospedaliero Cantonale, ABREOC 2019-22514, Bellinzona, Switzerland; European Research Council (ERC) Consolidator Grant CLLCLONE, ID: 772051; Swiss Cancer Research Foundation, ID 3746, 4395, 4660, 5257, Bern, Switzerland; Swiss National Science Foundation, ID 320030_169670/1, 310030_192439, 320036_179318, Berne, Switzerland; The Leukemia & Lymphoma Society, Translational Research Program, ID 6594-20, New York; AFRI, Ente Ospedaliero Cantonale, Bellinzona, Switzerland; ASH Global Research Award, Washington DC, USA; Worldwide Cancer Research (ID: 10583); ISREC Foundation; Helmut Horten Foundation, Switzerland; Fondazione Fidinam, Lugano, Switzerland; Nelia & Amadeo Barletta Foundation, Lausanne, Switzerland; Fond’Action, Lausanne, Switzerland; Fondazione Jacob, Lugano, Switzerland; Fondazione Dr. Ettore Balli, Lugano, Switzerland; Fondazione Ticinese per la Ricerca sul Cancro, Bellinzona, Switzerland; Jacques & Gloria Gossweiler Foundation, Berne, Switzerland. Keywords: Diagnostic and Prognostic Biomarkers, Hodgkin lymphoma, Liquid biopsy Conflicts of interests pertinent to the abstract. M. C. Pirosa Educational grants: BeiGene A. Condoluci Honoraria: AbbVie, AstraZeneca and Janssen Research funding: Gilead and Pfizer A. Moccia Honoraria: Janssen and Takeda A. Stathis Honoraria: Eli Lilly, Bayer, Roche, Novartis, Janssen Oncology, AstraZeneca Research funding: ADC Therapeutics, Pfizer, Roche, Novartis, Bayer, Eli Lilly, MEI Pharma, Cellestia, Debiopharm Group, Merck/MSD, Abbvie, Amgen, AstraZeneca, Incyte, Loxo, and Philogen C. Carlo-Stella Consultant or advisory role: Celgene/Bristol-Myers Squibb, ADC Therapeutics, Karyopharm 767 Therapeutics, Roche, and Sanofi Honoraria: Bristol-Myers Squibb, Merck Sharp & Dohme, Janssen Oncology, AstraZeneca, Incyte, Novartis, Takeda, ADC Therapeutics Research funding: ADC Therapeutics, Sanofi, Roche G. Gaidano Honoraria: Abbvie, Astra Zeneca, BeiGene, Incyte, Janssen E. Zucca Honoraria: BeiGene, BMS, Celltion Healthcare, Curis, Eli/Lilly, Incyte, Ipsen, Janssen, Kyte, Merck, Miltenyi, Roche Research funding: AstraZeneca, BMS, Incyte, Janssen, Merck, Roche Educational grants: Abbvie, BeiGene, Janssen and Roche D. Rossi Honoraria: AbbVie, AstraZeneca, BeiGene, BMS, Janssen Research funding: AbbVie, AstraZeneca, Janssen Educational grants: AstraZeneca and Janssen.