Citations

3516 Background: ICIs produce durable benefit in MSI-H CRC, yet optimal treatment duration and monitoring strategies remain unclear. ctDNA enables minimally invasive assessment of molecular response during and after ICI. We evaluated real-world treatment patterns, outcomes, and longitudinal ctDNA dynamics in pts with MSI-H CRC treated with ICI. Methods: Pts with MSI-H mCRC treated with first-line ICI were identified from Natera’s Real-World Database with linked longitudinal ctDNA results (Signatera, Natera, Inc.) and commercial claims data (Forian’s Hybrid data ecosystem, CHRONOS). Overall survival (OS) was estimated using available mortality data (Veritas Data Research, Fact of Death Mortality Data Index). ctDNA status was assessed pre-ICI when available and longitudinally following ICI initiation. Outcomes included OS and time to next trmt (TTNT); ctDNA dynamics following ICI discontinuation were descriptively evaluated. Results: Among 559 pts treated with first line ICI (pembrolizumab [70.1%], ipilimumab+nivolumab [15.7%], and nivolumab [11.8%]), the median duration of ICI was 266 days. Baseline (pre-ICI) ctDNA results were available for 180 pts, including 38% who were treated with chemotherapy, and most pts (71.7%, 129/180) were ctDNA-positive (ctDNA(+)) prior to ICI initiation. Of these, 89.9% (116/129) had ctDNA-timepoints after the start of ICI, and 81.0% (94/116) achieved anytime ctDNA clearance (from ctDNA(+) to negative), while 19.0% (22/116) remained ctDNA(+). ctDNA(+) at anytime after the start of ICI (HR: 8.0, p < 0.0001) or on first result after the start of ICI (HR: 3.4, p < 0.0001) was associated with inferior OS compared ctDNA-negativity (ctDNA(-)) at these time points. Among pts whose first post-ICI test was ctDNA(+), 32% switched treatments, with a median TTNT of 302 days, compared to only 6.6% of pts (median TTNT 683 days) whose first post-ICI test was ctDNA(-). First post-ICI ctDNA status was associated with longer ICI duration (median 192 days for ctDNA(+) vs 303 days for ctDNA(-)), and ctDNA(+) was predictive of inferior OS (HR: 4.9; p < 0.001). ctDNA after the end of ICI was available for 392 patients; it was persistently negative in 77.2% (303/392), persistently positive in 12.8% (50/392), cleared after the end of ICI (positive to persistently negative) in 4.1%, and the remaining 5.9% had variable patterns (e.g. positive to negative to positive). Conclusions: In this large real-world cohort of MSI-H mCRC treated with ICI, longitudinal ctDNA dynamics strongly correlated with treatment durability, time to subsequent therapy, and OS. These findings support further evaluation of ctDNA to inform treatment duration and surveillance strategies in MSI-H mCRC.

2646 Background: Immune checkpoint inhibitors (ICIs) have transformed the management of many advanced cancers but identifying patients who are likely or unlikely to benefit from ICI treatment remains a critical challenge. Biomarkers, such as PD-L1, mismatch repair deficiency, and tumor mutational burden, capture only static, unidimensional features of the complex tumor microenvironment, and therefore inadequately predict response to immunotherapy in patients. In contrast, live tumor fragments (LTFs) preserve the full complexity of the tumor microenvironment and enable functional ex vivo assessments of ICI activity. Previous efforts have had limited clinical applicability because they required larger resection specimens often collected at a single academic center. Here, the predictive capability of an ex vivo platform using core needle and forceps biopsies from multiple clinical sites was assessed and compared to approved biomarkers. Methods: Patients with eligible solid tumors (where ICI has an indication, including renal, non-small cell lung, bladder, colorectal, and triple-negative breast cancer, and others) were enrolled in ongoing, prospective observational trials (NCT05478538, NCT05520099, NCT06349642). Biopsies were cut into LTFs, encapsulated in hydrogel, and treated sequentially with IgG antibody followed by ICI (αPD-[L]1 with or without αCTLA-4). Cytokine production was assessed by a multiplexed bead-based immunoassay at multiple time points during ex vivo treatment. Using receiver operating characteristic and precision recall analyses, we identified 9 predictive cytokines (including IFN-γ, granzyme B, and CXCL9/10), which were used to develop the Elephas score (ELP-score) to assess cytokine response to ex vivo ICI treatment. Results: Of 167 eligible patient specimens, 85% (n = 142) passed quality control metrics and 130 were used for model development. Hierarchical clustering of cytokine production revealed that 27% (n = 35) of patient specimens exhibited a cytokine response to ICI. In a validation set of 20 tumors, collected from patients who were subsequently treated with ICI, ELP-score positivity correctly identified 9 of 11 patients (82%) who had an objective response (PR/CR) to ICI, including 2 patients who were negative for FDA-approved standard-of-care ICI biomarkers. Furthermore, 5 of 5 patients (100%) with clinical progressive disease were correctly characterized as ELP-score negative. Conclusions: Using routine biopsy specimens, the ex vivo live tumor platform accurately identifies patients with clinical response to ICI therapy, including those incorrectly identified by conventional biomarkers. Ongoing efforts will test these findings in an additional validation set. If confirmed, the ex vivo LTF platform could enable the identification of patients likely to benefit from ICI therapy. Clinical trial information: NCT05478538 , NCT05520099 , NCT06349642 .

11177 Background: Early detection of recurrence after curative-intent treatment is a critical priority, traditional imaging often detects relapse when disease burden is high, potentially limiting treatment efficacy. ctDNA has emerged as an established prognostic biomarker for molecular residual disease (MRD) detection and early relapse. We performed a real-world meta-analysis on published datasets that utilized personalized, tumor-informed ctDNA testing to assess its performance across tumor types and clinical management approaches. Methods: Real-world studies published from December 2022 to December 2025 using the personalized, tumor-informed Signatera ctDNA assay (Natera, Inc.) were included. Eligibility required ctDNA assessment in the MRD (2–16 weeks post-surgery (histology dependent)/pre adjuvant therapy (ACT)) and/or surveillance (post-ACT/end of the MRD window if no ACT was given) settings, with outcomes stratified by ctDNA status and hazard ratios (HR) reported from univariable or time-dependent Cox regression analysis. Exclusions included: clinical trials, biobanks, metastatic disease treated with palliative intent, case reports, reviews, editorials, or commentaries. Clinical outcomes were harmonized into a composite event-free survival (EFS) endpoint (time to recurrence, progression, or death). Pooled HRs and 95% CIs were estimated using random and fixed effects models and heterogeneity between studies was assessed using the I 2 and Cochran’s Q test. Median lead time from ctDNA-positivity to radiographic or clinical recurrence was summarized when available. Results: We identified 18 eligible publications comprising 3,004 unique patients across 15 solid tumor types. During the MRD window, ctDNA positivity was associated with a significantly increased risk of an EFS event compared with ctDNA negativity (pooled HR: 8.15; 95% CI: 6.12–10.85, I 2 = 0.00%, P = 0.844, n = 13). During the surveillance window, inclusive of post-definitive treatment, ctDNA positivity conferred an even greater EFS risk (pooled HR: 18.30; 95% CI: 14.17–23.65, I 2 = 0%, P = 0.911 for heterogeneity, n = 16). Across studies, ctDNA detection during surveillance preceded radiographic or clinical recurrence by a median of 3.20 months (95% CI: 2.50-4.10, P < 0.0001, n = 10), although this varied substantially by study/tumor type (I 2 = 80.9%). Conclusions: In this pan-cancer real-world meta-analysis, ctDNA positivity assessed using a tumor-informed assay was highly prognostic following curative-intent therapy at all timepoints evaluated with low heterogeneity between studies. These findings support the broad clinical utility of tumor-informed ctDNA testing for post-treatment risk stratification and longitudinal disease monitoring across solid tumors.

10610 Background: The role for genetic testing (GT) for prostate cancer (PCa) patients (pts) has expanded to find pts with germline pathogenic variants (PV) for therapeutic opportunities given FDA-approvals for PARP inhibitors in metastatic PCa as well as understanding familial cancer risk and opportunities for tailored screening and risk reduction. The PROMISE Registry (NCT04995198) was set up as a genetic registry to partner with PCa pts for rapid access to a new standard of care given insurance coverage and clinical implementation were initially major barriers. A second goal is to characterize disease features and treatment outcomes to inform management and provide updates about novel therapeutic clinical trials, both of which remain important to rare genetic variant carriers. Methods: PROMISE is a US decentralized prospective PCa genetic registry initiated in 2021 with initial phase to enroll and provide clinical-grade germline genetic testing (30 gene cancer-specific panel) to 5,000 PCa pts to identify ~500 PCa pts with variants of interest (pathogenic variants, PV, and variants of uncertain significance, VUS) in DNA repair genes for long-term clinical follow-up of 15 years (LTFU). Here, we report the initial phase testing results and identification of the LTFU cohort. Study design and enrollment strategy have been reported separately. Results: Between 2021-2026, 7,275 pts with any stage PCa across 50 US states self-consented to PROMISE, of which 5,674 (78%) of pts completed genetic testing, indicating feasibility of patient-directed, decentralized enrollment. We have identified 495 (8.7%) pts for LTFU. Baseline data is reported for n=367 (Table 1, will be updated at time of presentation). The most frequently observed PV/LPV variants being in CHEK2 (25%) , BRCA2 (23%) , ATM (12%) , and BRCA1 (4.6%). At the time of PCa diagnosis, the majority of LTFU pts had non-metastatic disease, with 47% of pts with Gleason>7, median PSA of 5 ng/mL, and median time from diagnosis to PROMISE GT of 25 months. Conclusions: PROMISE is a nationwide decentralized PCa genetic registry that has completed initial goal to recruit 5,000 PCa pts to offer germline genetic testing and recruit a cohort of 500 for LTFU. Data about diagnosis characteristics are reported, and analysis of ongoing disease course, treatment response/outcomes and overall survival is being collected. Clinical trial information: NCT04995198 . Long-term follow-up participant demographics. Characteristic Overall, N = 367 Age at Diagnosis (yrs) 63 (57, 69) Race N = 361 (6, nr) Asian, American Indian or Alaska Native, Multiracial, Other 22 (6.0%) Black or African American 22 (6.0%) White 317 (86%) Disease State at Diagnosis N = 348 (19, nr) Metastatic 46 (13%) Non-metastatic 302 (87%) Time from Diagnosis to PROMISE GT (months) 25 (4, 82) Gleason Score N = 280 (87, nr) </= 7 148 (53%) >7 132 (47%) PSA At Diagnosis (ng/mL) 5 (0, 10) (88, nr) Subjects with baseline data entered. nr=not reported. Median (Q1, Q3); n (%).

SUMMARY Neurodegenerative diseases are often accompanied by systemic comorbidities, including changes in bone health, but the molecular relationship between neurodegeneration, skeletal decline, and cellular senescence remains poorly understood. In this study, we investigated sex-specific changes in circulating bone- and senescence-related proteins across the spectrum of Alzheimer’s disease(AD), Lewbody dementia(LB) and Parkinson’s disease(PD). Plasma proteomic profiling was performed on samples from 408 participants deeply phenotyped for neurodegenerative diseases, followed by differential protein and pathway analyses. This study reveals sex-dependent alterations in bone and senescence-related circulating proteins in AD-related, PD and LB-related neurodegenerative diseases, providing insights into the complex relationship between neurodegeneration and bone health. Several candidate proteins were also associated with established plasma neurodegeneration biomarkers, particularly pTau181. Pathway analyses revealed shared mitochondrial and metabolic dysfunction across neurodegenerative diseases, with disease-specific features including vesicle trafficking disruption in AD and inflammatory-senescence pathways in LB, plus sex-divergent patterns in inflammatory signaling and bone-related pathways.

OBJECTIVE Historically, craniopharyngioma (CP) was divided into adamantinomatous CP (ACP) and papillary CP (PCP) subtypes based on histopathological features. However, each harbors a unique genetic profile and progressively differing treatment paradigms, leading to their reclassification by the WHO in 2016 as two distinct entities. Descriptive in nature, this large multi-institutional study aimed to establish current differences between the presentation, treatment patterns, and clinical course of these pathologies to serve as a baseline for future studies as new treatment paradigms emerge. METHODS The authors queried the Registry for Adenomas of the Pituitary and Related Disorders (RAPID) database, which encompassed patients from 14 participating institutions across the United States between 2000 and 2024. The database was screened for adult patients who underwent initial CP treatment with a confirmed histopathological diagnosis of ACP or PCP. Patient demographic characteristics, clinical course, tumor treatment, and outcomes data were collected and compared by CP type. RESULTS The final analysis included 273 ACP and 99 PCP adult patients who underwent initial surgical treatment. ACP patients presented younger on average (mean 48.3 vs 52.8 years, p = 0.034). PCP patients were more likely to present with hypothyroidism (33.3% vs 20.5%, p = 0.010), hyperlipidemia (25.3% vs 15.8%, p = 0.036), fatigue (28.3% vs 17.6%, p = 0.024), temperature intolerance (9.1% vs 1.5%, p < 0.001), and cardiac arrhythmia (6.1% vs 1.1%, p = 0.006). The groups demonstrated similar postsurgical and neuroendocrinological outcomes. Postoperative median (IQR) progression-free survival did not significantly differ between groups (19.0 [7.0–37.0] for ACP vs 5.0 [3.5–7.5] months for PCP, p = 0.972). ACP patients were more likely to receive radiation after surgery (27.8% vs 15.2%, p = 0.012). CONCLUSIONS This large multicenter descriptive study aimed to characterize similarities and differences between the clinical courses of molecularly distinct ACP and PCP, which has not previously been described. The findings should serve as a baseline to inform future studies, particularly with the recent introduction of targeted therapy for PCP.

OBJECTIVE Frailty is a known predictor of adverse outcomes in pituitary surgery, yet its impact regarding craniopharyngioma remains unclear. The authors assessed preoperative frailty, measured by the 11-factor modified frailty index (mFI-11), and its association with perioperative morbidity among adult patients undergoing craniopharyngioma surgery. METHODS Using the Registry for Adenomas of the Pituitary and Related Disorders (RAPID) database, the authors performed a retrospective cohort study of the records of patients ≥ 18 years of age who underwent craniopharyngioma surgery between June 2007 and November 2024. Patients were stratified into the following categories according to their numeric mFI-11 score: fit (scores 0 and 1), managing well (scores 2 and 3), and mildly frail (scores 4–6). Primary outcomes included hospital length of stay (LOS) and discharge disposition. Secondary outcomes included 90-day readmission, surgical outcomes, and complications. Multivariable analyses were performed to identify independent predictors of hospital LOS and non-home discharge, adjusting for age, surgeon experience, American Society of Anesthesiologists class, complications, and surgical approach. RESULTS Among 278 patients (221 fit, 43 managing well, 14 mildly frail), higher-frailty patients were older (mean age 47.8 ± 16.1 years in fit vs 60.1 ± 12.5 years in managing well vs 67.6 ± 8 years in mildly frail, p < 0.001) and more likely to present urgently (24.2% vs 36.4% vs 78.6%, p = 0.001). Gross-total resection was achieved less frequently in frail patients (44.8% vs 24.3% vs 23.1%, p = 0.030). Overall complication rates were similar; however, increasing frailty was associated with higher rates of postoperative mortality (0% vs 2.8% [1/36] vs 7.7% [1/13], p = 0.018), pneumonia (0.5% [1/195] vs 2.8% [1/36] vs 15.4% [2/13], p = 0.006), and reintubation (2.6% [5/195] vs 2.8% [1/36] vs 30.8% [4/13], p = 0.002). Higher frailty was associated with a stepwise rise in median [IQR] LOS (5 [3–8] days vs 7 [4–12] days vs 13 [6.5–21.8] days, p < 0.001) and remained an independent predictor of extended LOS on multivariable analysis (β = 1.729 per point, p = 0.006). Rates of non-home discharge showed a similar pattern (9.2% vs 30.0% vs 64.3%, p < 0.001), with frailty independently predicting non-home discharge (OR 2.352, 95% CI 1.527–3.822). Unplanned 90-day readmission rates were significantly higher in the mildly frail cohorts (22.5% vs 45.7% vs 53.8%, p = 0.002). CONCLUSIONS The mFI-11 scores independently predicted perioperative morbidity following craniopharyngioma resection. Incorporating frailty screening into preoperative screening may improve risk stratification, family and patient counseling, and discharge planning.

OBJECTIVE Craniopharyngiomas are benign intracranial tumors that can be difficult to manage operatively and often result in postoperative complications and prolonged recovery. Understanding the factors that influence length of stay (LOS), discharge disposition, and readmission can guide perioperative planning and patient counseling. The authors examined the clinical, radiographic, and surgical predictors of extended LOS (eLOS), nonhome discharge, 90-day readmission, and hospitalization ratio (HR) after craniopharyngioma resection using a large, multicenter cohort. METHODS A retrospective analysis was conducted using the Registry of Adenomas of the Pituitary and Related Disorders database, encompassing 469 patients who underwent craniopharyngioma resection at 14 US academic centers from 2011 to 2025. Patients were stratified by 4 outcomes: eLOS (> 75th percentile), discharge to home versus skilled nursing facility/rehabilitation, 90-day hospital readmission, and hospitalization ratio (i.e., integration of initial and readmission LOS). Multivariable logistic regression models identified independent predictors for each outcome among patient and surgical variables. RESULTS An eLOS (> 10 days) was independently associated with preoperative memory loss (OR 3.75, 95% CI 1.95–7.21), gait imbalance (OR 5.90, 95% CI 1.53–22.70), and postoperative complications (OR 4.07, 95% CI 2.34–7.06). The use of a nasoseptal flap was protective against an eLOS (OR 0.52, 95% CI 0.28–0.93). Discharge to home was predicted by an endoscopic approach (OR 3.87, 95% CI 1.78–8.44) and postoperative intact thirst (OR 2.22, 95% CI 1.05–4.66) and negatively predicted by preoperative diabetes mellitus (OR 0.21, 95% CI 0.09–0.50), LOS (OR 0.87, 95% CI 0.84–0.91), and postoperative cognitive dysfunction (OR 0.30, 95% CI 0.13–0.72). Among 385 patients with follow-up data, a 90-day readmission was independently associated with postoperative complications (OR 5.62, 95% CI 3.12–10.13), preexisting coronary artery disease (OR 4.30, 95% CI 1.46–12.69), and postoperative cognitive dysfunction (OR 3.33, 95% CI 1.76–6.44). A higher HR was associated with diabetes mellitus (unstandardized B 0.059, 95% CI 0.010–0.108, p = 0.02), postoperative complications (unstandardized B 0.054, 95% CI 0.021–0.086, p = 0.001), and postoperative cognitive dysfunction (unstandardized B 0.049, 95% CI 0.006–0.092, p = 0.02). Tumor pathologic subtype and size, prior treatment, extent of resection, and surgeon experience were not directly predictive of outcomes. CONCLUSIONS Cognitive and functional status, systemic comorbidities, and postoperative complications, in addition to surgical approach, are important predictors of the early clinical course after craniopharyngioma surgery. Early identification of high-risk patients may help to guide treatment decisions, improve discharge planning, and reduce healthcare utilization.