Kumar, Harendra

Atezolizumab-bevacizumab and durvalumab-tremelimumab have established immunotherapy as a first-line standard of care in advanced hepatocellular carcinoma (HCC). Yet, objective response rates (ORRs) remain confined to approximately 15-20%, and no validated predictive biomarker exists for patient selection. Unlike melanoma and lung cancer, conventional markers, including programmed death-ligand 1, microsatellite instability-high status, and tumor mutational burden, have not demonstrated reliable predictive value in HCC. Prior narrative reviews comprehensively catalogued the biomarker landscape through 2022 but predate a wave of clinically significant publications. This narrative review synthesizes evidence published between 2020 and 2026, with particular emphasis on 2023–2026 data, within a unified clinical framework not provided by prior reviews. We critically evaluate tissue-based biomarkers, including the AI-derived Atezolizumab-Bevacizumab Response Signature-Pathology model, spatial multiplex immunohistochemistry, and β-catenin mutational profiling; blood-based biomarkers encompassing circulating tumor DNA for minimal residual disease detection and peripheral immune phenotyping; and serum indices including the CRAFITY score and neutrophil-to-lymphocyte ratio. Hepatitis B virus etiology and non-alcoholic steatohepatitis are discussed as biological modifiers of biomarker performance. We propose an original biomarker-guided clinical algorithm, a comparative clinical readiness table, and a disease-continuum biomarker timeline as practical tools for clinicians and trialists. Prospective biomarker-enrichment trials represent the most critical next step toward clinical translation.

Background Circulating tumor DNA (ctDNA) has rapidly evolved from a research tool to a clinically applicable biomarker in colorectal cancer (CRC), transforming the assessment of minimal residual disease (MRD) and recurrence risk. The growing availability of commercial assays has complicated test selection and interpretation, particularly for gastroenterologists who increasingly encounter ctDNA data in postoperative and surveillance settings. Methods We conducted a narrative review of the literature using PubMed, Embase, and Cochrane databases from January 2015 through March 2026, prioritizing randomized controlled trials, prospective cohort studies, and clinical practice guidelines relevant to ctDNA applications in CRC. The search employed predefined keyword combinations applied independently to each database. Two authors (A.S. and S.M.) independently screened titles and abstracts against the prespecified inclusion criteria, with disagreements resolved by discussion. Results Tumor-informed assays that analyze patient-specific mutations exhibit high specificity for MRD detection, with serial sampling sensitivity reaching 88% compared to 59% for tumor-agnostic approaches, based on a 2026 systematic review and diagnostic accuracy meta-analysis that pooled data across multiple platforms and settings; the authors note substantial study-level heterogeneity in platform design and patient populations, and results should be interpreted accordingly, but require tissue access and extended processing times. Tumor-agnostic tests are more rapid and accessible, incorporating genomic and epigenomic signals, though they exhibit site-specific sensitivity variations ranging from 100% for liver metastases to 40% for peritoneal recurrence and remain vulnerable to biological confounders such as clonal hematopoiesis (CH). Importantly, ctDNA interpretation is subject to additional biological limitations including tumor shedding variability by anatomical site and disease burden, the timing of sample collection relative to surgery or chemotherapy, platform-specific detection thresholds, and pre-analytical variables such as hemolysis and delayed plasma processing. Randomized evidence supports ctDNA-guided de-escalation of adjuvant therapy in stage II colon cancer, with 5-year follow-up from the DYNAMIC trial demonstrating comparable recurrence-free survival (88% vs. 87%) and overall survival (93.8% vs. 93.3%) despite reduced chemotherapy use. In stage III disease, ctDNA is strongly prognostic, but chemotherapy intensification based solely on molecular positivity has not improved outcomes. This review additionally addresses underexplored areas including ctDNA in rectal cancer and neoadjuvant therapy, the influence of microsatellite instability (MSI) status on assay performance, and disparities in ctDNA access across racial, socioeconomic, and geographic populations. Conclusions For gastroenterologists encountering ctDNA results in postoperative and surveillance settings, three principles should guide practice (i): match assay selection to clinical intent - tumor-informed platforms for MRD-directed adjuvant decisions, tumor-agnostic platforms when tissue is unavailable (ii); interpret results within biological and technical context, accounting for platform-specific sensitivity limitations, biological confounders, and quantitative VAF trajectory rather than binary thresholds; and (iii) integrate ctDNA findings into multidisciplinary pathways - de-escalation is supported by high-quality randomized evidence in stage II disease (Grade A; Level I), while chemotherapy escalation based solely on ctDNA positivity in stage III disease is not supported outside clinical trials (Grade C; Level I). Standardization of assay performance benchmarks and equitable access to testing remain critical unmet needs.

Colorectal cancer (CRC) is responsible for a high cancer burden and a high number of deaths all over the world, although effective screening can make it preventable to a significant extent. Stool-based tests, such as the fecal immunochemical test (FIT) and multitarget stool DNA (mt-sDNA) testing, are gaining considerable popularity as non-invasive procedures that can be a replacement for colonoscopies for people at an average risk for colon cancer. Despite evidence from several randomized controlled trials supporting the use of these tests for colorectal cancer screening, their external validity in a real-world setting is influenced by many factors such as adherence, timely follow-up post testing, the healthcare cost burden, accessibility and the capacity of the health system. In this article, we have performed an extensive narrative literature review of research published between 2020 and 2025 comparing FIT and the mt-sDNA test with reference to diagnostic accuracy, cost-effectiveness, adherence and outcomes of implementation. We discuss the issues of sensitivity and specificity, look at post-test requirements for colonoscopy and check if there is any discrimination in healthcare. These findings suggest that FIT and mt-sDNA tests should not be considered competing technologies but rather complementary screening methods, with their overall effectiveness contingent upon appropriate patient selection and widespread system-level implementation. It is crucial to combine strategic test selection with a robust follow-up infrastructure to ensure that the entire population benefits from the CRC prevention program.

e19116 Background: PET/CT is the primary end-of-treatment (EOT) evaluation for diffuse large B-cell lymphoma (DLBCL); yet, false positives and insufficient prognostic clarity continue to be significant problems. Circulating tumor DNA (ctDNA)-based minimum residual disease (MRD) provides a tumor-informed, noninvasive way to assess recurrence risk. Methods: We used the MEDLINE, Embase, CENTRAL, and Web of Science databases to perform a systematic review and meta-analysis in accordance with PRISMA 2020 guidelines. DLBCL cohorts with end-of-treatment ctDNA-MRD status and survival outcomes were considered eligible research. The key outcome measures were progression-free survival (PFS) and overall survival (OS). Random-effects models calculated hazard ratios (HRs) and measured heterogeneity using I². Results: Eleven trials with 1,247 participants were included. Individuals with ctDNA-MRD had significantly worse progression-free survival (PFS) (pooled HR 5.48, 95% CI 3.96-7.58; I² = 42%) and overall survival (OS) (pooled HR 4.21, 95% CI 2.71-6.54; I² = 36%) compared to those without MRD. In MRD-positive patients, the 24-month recurrence rate was 68% compared to 14% in MRD-negative patients (absolute difference 54%, p < 0.001), with ctDNA indicating return 4.2 months before clinical advancement. In studies reporting combined PET/CT, ctDNA-MRD showed superior predictive performance, with a higher positive predictive value (79% vs 41%) and negative predictive value (92% vs 78%) compared to PET positivity. Conclusions: End-of-treatment ctDNA-MRD is a strong predictor of DLBCL recurrence and survival, outperforming PET/CT for risk classification. Integrating ctDNA-MRD into post-therapy assessments may allow for early intervention and reduce the number of unnecessary biopsies. Clinical Takeaway: ctDNA-MRD at EOT identifies high-risk DLBCL patients missed by imaging and supports precision-guided post-remission management.

e19092 Background: Advances in immunochemotherapy and cellular treatment have improved outcomes for diffuse large B-cell lymphoma (DLBCL), but the population-level effect and equity of benefit are unclear. Understanding mortality trends and inequality is critical to developing targeted medicines. Methods: We used ICD-10 codes to assess DLBCL mortality from the CDC WONDER Multiple Causes of Death data (1999-2023). The age-adjusted mortality rates (AAMR) per 100,000 were calculated using the 2000 US standard population. Trends were assessed using Joinpoint regression to calculate annual percent change (APC) and average annual percent change (AAPC). Mortality was broken out by gender, race/ethnicity, age group, US Census area, and urban-rural categorization. Results: From 1999 to 2023, the national AAMR for DLBCL decreased from 3.8 to 2.5 per 100,000 (AAPC -2.1%) (p < 0.001). Non-Hispanic White patients saw the greatest decline (AAPC -2.5%), followed by non-Hispanic Black patients (AAPC -1.2%), resulting in increasing racial inequalities (rate ratio Black:White 1.35 in 2023 vs. 1.18 in 1999). Urban areas had much larger mortality decreases than rural areas (AAPC −2.3% versus −1.1%). Regional disparities were clear, with rates typically higher in the Southeast and Midwest. Inflection points were identified in 2006 and 2012, coinciding with widespread use of rituximab-based therapy and better availability of second-line medications. Conclusions: Although DLBCL mortality has decreased throughout the US over the last two decades, progress has been patchy, with significant racial and regional differences. Clinical Takeaway: Targeted interventions addressing access to therapy and early detection in high-risk populations are needed to close persistent DLBCL outcome gaps.

e19090 Background: PET/CT remains crucial for end-of-treatment (EOT) evaluation in large B-cell lymphoma (LBCL), but low specificity results in unnecessary biopsies and patient discomfort. Circulating tumor DNA (ctDNA)-based minimum residual illness (MRD) may aid in the identification of actual residual sickness. Methods: We conducted a systematic review and meta-analysis of diagnostic accuracy using MEDLINE, Embase, CENTRAL, and Scopus. Eligible studies compared EOT ctDNA-MRD to PET/CT with verified recurrence or long-term remission. The outcomes were sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). The study's quality was rated using the QUADAS-2 scale. A bivariate random-effects model combined sensitivity and specificity, yielding hierarchical summary receiver operating characteristic (HSROC) curves. Results: Nine studies with a total of 932 participants were included. ctDNA-MRD showed higher specificity (92%, 95% CI 88-95%) and PPV (81%, 95% CI 73-88%) than PET/CT (specificity 68%, 95% CI 60-75%; PPV 46%, 95% CI 38-55%), while maintaining similar sensitivity. The negative predictive value for ctDNA was higher (91%, 95% CI 86-95%) than for PET (79%, 95% CI 72-85%). Combined PET+ctDNA techniques had the highest diagnostic odds ratio and fewer false positives. The results were similar across Deauville criteria and testing systems. Conclusions: ctDNA-MRD has higher specificity and predictive value than PET/CT at EOT in LBCL and significantly improves risk categorization whether used alone or in conjunction with imaging. Clinical Takeaway: Incorporating ctDNA-MRD into EOT assessment can reduce unnecessary biopsies and enable more accurate, confidence-based post-treatment decision-making.

e14102 Background: High-quality glioma surgery requires multidisciplinary expertise, yet access to high-volume centers varies. National estimates of inpatient morbidity and resource utilization can identify actionable quality gaps and disparities. Methods: We analyzed the HCUP National Inpatient Sample (NIS) for adult admissions undergoing intracranial glioma resection from 2016–2022. Primary outcomes were in-hospital mortality and major complications (neurologic, infectious, thromboembolic, hemorrhagic). Secondary outcomes included length of stay (LOS), total charges, non-home discharge, and weekend admissions. Survey-weighted methods generated national estimates, and multivariable regression evaluated associations with hospital volume, teaching status, region, and patient-level socioeconomic variables, adjusting for age, comorbidities, and admission urgency. Results: Among 23,874 weighted admissions, in-hospital mortality was 2.1%, and major complications occurred in 14.7%. High-volume centers had lower odds of mortality (adjusted OR 0.62, 95% CI 0.51–0.75) and complications (OR 0.71, 95% CI 0.63–0.80) compared with low-volume hospitals. LOS was shorter at high-volume centers (median 5 vs 7 days, p < 0.001), with lower total charges. Patients from lower-income quartiles and rural areas had higher odds of complications and non-home discharge (OR 1.33, 95% CI 1.11–1.59). Weekend admissions were associated with modestly higher complication rates (OR 1.12, 95% CI 1.01–1.24). Conclusions: National inpatient outcomes for glioma resection vary by hospital volume and patient socioeconomic factors, highlighting disparities in access to high-quality surgical care. Clinical takeaway: Referral to high-volume centers and targeted support for vulnerable populations may reduce complications, optimize resource utilization, and improve equity in glioma surgical care.

Antibody–drug conjugates (ADCs) are reshaping the therapeutic approach to advanced gastrointestinal cancers by integrating tumor-specific monoclonal antibodies with potent cytotoxic payloads to improve targeted tumor cell destruction while minimizing systemic exposure. Compared to traditional chemotherapy, trastuzumab deruxtecan has significantly improved objective response rates and overall survival in HER2-positive gastric and gastroesophageal junction tumors after trastuzumab-based therapy. This supports its role as an important second-line or later treatment option. The ongoing advancement of ADCs targeting CLDN18.2, TROP2, and CEACAM5 indicates that this therapeutic category will continue to expand across gastrointestinal neoplasms. Nonetheless, these advancements are accompanied by a specific and clinically significant toxicity profile. Hematologic suppression, gastrointestinal side effects, hepatotoxicity, and notably interstitial lung disease (ILD) are essential consequences that may need inpatient assessment and care. Interstitial lung disease (ILD), although uncommon, may be severe or lethal if not identified immediately and treated swiftly with medication cessation and corticosteroids. In hospitalized patients, distinguishing ADC-related toxicity from infection or disease progression is often difficult owing to overlapping clinical manifestations, requiring meticulous evaluation and interdisciplinary cooperation. As ADCs are integrated into earlier treatment lines and across a broader patient population, hospital systems must evolve to ensure prompt identification, consistent management protocols, and efficient collaboration between oncology and inpatient teams. This study analyzes the mechanisms, clinical effectiveness, and safety profile of ADCs in gastrointestinal oncology, pointing out the importance of institutional preparedness to safely incorporate these medicines into standard clinical practice. These features also align ADC therapy with personalized medicine by emphasizing biomarker-guided patient selection and individualized toxicity monitoring.