Citations

Abstract Modern radiation therapy (RT) technologies allow for improved sparing of normal tissues, decreasing the risk of both acute and long-term toxicities. Existing RT dose constraints for prospective trials within the National Clinical Trials Network (NCTN) were formulated in the context of solid malignancies. As patients with hematologic malignancies are often treated with lower RT doses and are usually younger with more favorable prognoses, customized dose constraints are needed. The NRG Oncology Hematologic Malignancies Working Group (NRG HEME) commissioned a review of existing organ-at-risk (OAR) constraints from published primary literature, the NRG Center for Innovation in Radiation Oncology (CIRO), and national guidelines. Customized constraints were developed by iterative review by NRG HEME. Final recommendations were approved by radiation oncology representatives from all the lymphoma NCTN groups (NRG Oncology, Children’s Oncology Group, Alliance, ECOG-ACRIN, SWOG, Canadian Cancer Trials Group). For 49 OARs, a strict recommended constraint was determined, of which 20 were not present in CIRO. Of the remaining 29 constraints, 20 were lower, 2 were the same, and 5 used different metrics; 2 were higher than at least 1 CIRO trial constraint. Acceptable variations were determined and unacceptable variations were added for select critical OARs for plan scoring. While doses to OARs without explicit unacceptable variations should not exceed acceptable variations, violations should not be considered for plan quality assessment on trials. This consensus list of standard OAR constraints should be incorporated for all future NCTN trials in hematologic malignancies. Strict dose constraints will minimize long-term toxicities in this patient population.

Abstract Purpose: This multicenter, multi-surgeon retrospective study aimed to identify risk factors for postoperative cerebrospinal fluid (CSF) leak following endonasal resection of craniopharyngioma, while evaluating the "perception gap" through a surgeon survey. Methods: A retrospective review was conducted on 416 patients who underwent endoscopic transsphenoidal surgery (ETS) for craniopharyngioma from 20 institutions. Factors were compared between patients with and without postoperative CSF leak, and between Early (2007-2015) and Late (2016-2025) Epochs. Complementing the clinical data, a survey of 19 neurosurgeons captured expert perspectives on risk stratification and management strategies. Results: Overall postoperative CSF leak rate was 13.5% (56/416 patients). Univariate analysis identified predominantly cystic tumors (34% vs. 21%, p = 0.034)and intraoperative lumbar drain (LD) use ( p < 0.028) as associated with postoperative CSF leak. BMI ( p = 0.587), prior surgery ( p = 0.576), and tumor size ( p = 0.363) were not significant. In the multivariable analysis, LD use was associated with a higher postoperative CSF leak rate (OR 1.91, 95% CI 1.06–3.46; p = 0.030). Between Epochs, nasoseptal flap (NSF) utilization increased from 70.7% to 87.6% ( p <0.001). NSF was protective (OR 0.28, 95% CI 0.07–0.92; p = 0.037) in the Early Epoch; no factors were significant in the Late Epoch. The surgeons’ survey identified prior surgery and intraoperative high flow leaks as primary risks; however, their LD protocols diverged from clinical data. Conclusion: Despite increased use of NSF, CSF leak persists. The study highlights a significant divergence between expert perception and clinical data regarding lumbar drains.

Introduction Preoperative testosterone exposure has been associated with various health outcomes, but its impact on postoperative complications in patients undergoing total shoulder arthroplasty (TSA) has not been fully explored. This study aims to evaluate the association between preoperative testosterone exposure and postoperative medical and surgical complications in patients undergoing TSA. Methods A retrospective cohort study was conducted using the PearlDiver database. Patients who underwent TSA and used preoperative testosterone within 3 months of the index procedure were identified and matched 1:4 to controls without testosterone use using propensity score matching. Matching was performed based on age, gender, comorbidities, Charlson comorbidity index, obesity, tobacco use, and hypogonadism to balance the groups. Postoperative complications were assessed at 90 days and five years. Statistical comparisons were made using odds ratios (ORs) with 95% confidence intervals (CIs), and a p -value of <0.05 was considered statistically significant. Results The matched cohort included 677 testosterone users and 2554 controls. There were no statistically significant differences between the testosterone and control groups in 90-day complications such as myocardial infarction (OR 2.52, P = 0.31), pneumonia (OR 0.86, P = 0.70), and deep vein thrombosis (no cases in the testosterone group). Over five years, the testosterone group had a significantly higher risk of periprosthetic joint infection (4.1% vs. 2.4%, OR 1.76, 95% CI 1.10–2.75, P = 0.015), but no differences in revision rates, dislocation, aseptic loosening, or stiffness were observed. Conclusion Preoperative testosterone exposure was associated with a higher risk of periprosthetic joint infection following TSA, but no significant differences were found in major medical complications or revision rates.

ABSTRACT Introduction/Aims Eplontersen is approved in multiple regions for adults with hereditary transthyretin amyloidosis with polyneuropathy (ATTRv‐PN). This exploratory analysis was conducted to evaluate the treatment effect of eplontersen by sex in patients with ATTRv‐PN from the NEURO‐TTRansform trial (NCT04136184). Methods Participants in NEURO‐TTRansform who received ≥ 1 dose of eplontersen were included in this analysis; participants in the inotersen reference group who switched to eplontersen were excluded. Eplontersen was evaluated in the overall patient population and in a subgroup with cardiomyopathy. Change from baseline in the NEURO‐TTRansform primary endpoints of serum transthyretin (TTR) levels to Week 65, modified Neuropathy Impairment Score +7 (mNIS+7) composite score to Week 66, and Norfolk Quality of Life‐Diabetic Neuropathy (Norfolk QoL‐DN) total score to Week 66 were evaluated. A historical placebo group from the NEURO‐TTR trial (NCT01737398) was included as a control. Results The eplontersen group comprised 100 (69.4%) male and 44 (30.6%) female patients. The placebo group comprised 41 (68.3%) male and 19 (31.7%) female patients. For both sexes, treatment with eplontersen decreased serum TTR levels by > 80% (vs. reductions of 3%–13% with placebo), maintained mNIS+7 scores, and improved Norfolk QoL‐DN scores (vs. deterioration with placebo). The treatment effect of eplontersen was similar in male and female patients with cardiomyopathy. Discussion Eplontersen halted neuropathy impairment and improved quality of life versus placebo to a similar degree in both male and female patients with ATTRv‐PN, including those with cardiomyopathy. These findings support the use of eplontersen as an effective treatment for ATTRv‐PN regardless of sex.

PURPOSE Homologous recombination deficiency (HRD) is a key determinant of sensitivity to DNA-damaging agents; however, its genomic characterization in colorectal cancer (CRC) remains limited. This study investigated whether low RNA expression of homologous recombination (HR) genes identifies patients with metastatic CRC who derive survival benefit from oxaliplatin- or irinotecan-based therapy. METHODS A total of 22,957 metastatic CRC samples were subjected to DNA and RNA sequencing (Caris Life Sciences, Dallas, TX). Patients with microsatellite instability–high or pathogenic HR gene mutations were excluded to define a HR-proficient cohort. Overall survival (OS) was compared between patients with low (bottom 25%) versus high (top 25%) RNA expression of HR genes after oxaliplatin or irinotecan exposure. Validation was performed in the PARADIGM phase III trial cohort (n = 262) of first-line modified fluorouracil, leucovorin, and oxaliplatin-treated patients with available RNAseq data. RESULTS In the discovery cohort, low expression of core HR genes correlated with significantly longer OS after oxaliplatin or irinotecan exposure, specifically RAD51 (43.0 v 36.3 months; P < .005) and BLM (42.9 v 34.2 months; P < .005). Similar associations were observed for RAD51 (28.1 v 22.9 months; P = .02) and BLM (29.1 v 23.2 months; P < .005) in irinotecan-treated patients. In the PARADIGM validation cohort, low BLM expression was associated with improved OS (41.5 v 22.4 months; HR = 0.52; P = .002), whereas RAD51 showed a favorable but nonsignificant trend. These findings remained significant after adjustment for treatment arm, tumor sidedness, and metastatic burden. CONCLUSION Low BLM RNA expression is associated with improved survival after treatment with DNA-damaging agents, whereas low RAD51 expression shows a favorable but nonsignificant trend. These findings are exploratory and suggest that RNA-based HR gene expression may warrant further investigation as a potential prognostic biomarker in metastatic CRC.

Abstract Breast and ovarian cancers are major causes of cancer mortality in women with frequent relapse after curative intent treatment, underscoring the need for novel therapeutics. To this end, we identified CTPS1 as an essential gene in multiple breast and ovarian cancer models, including those resistant to chemotherapy and PARP inhibitors. CTPS1 and CTPS2 are responsible for de novo synthesis of cytidine triphosphate (CTP) which is required for DNA/RNA polymerization, phospholipid synthesis and protein glycosylation. We found CTPS1 to be the predominant isoform expressed in cancer cells, with significantly higher levels in advanced and resistant disease models compared to normal tissue, benign lesions and treatment naïve cancers. Using CTPS1 siRNAs and CTPS1-dTAG (degradation tag) cell lines, we discovered that depletion of CTPS1 induces S-phase cell cycle arrest followed by apoptosis. Leveraging a first-in-class, highly selective, and orally bioavailable CTPS1 inhibitor (STP938) developed by Step Pharma, we identified nanomolar IC50 values across a panel of cell lines, both in 2D and 3D culture systems, and potent anti-neoplastic activity ex vivo and in vivo using patient-derived xenograft (PDX) models. STP938 also synergized with standard-of-care chemotherapy agents and PARP inhibitors, including in therapy-resistant models. Given the essentiality of CTP for biosynthetic processes, we performed bulk and single cell RNA-seq, total and phospho-proteomics, metabolomics, and lipidomic strategies to examine changes induced by acute and chronic STP938 exposure. This revealed that cancer cells are able to overcome pharmacologic CTPS1 inhibition by rewiring of pyrimidine and purine synthesis pathways, upregulation of the pentose phosphate pathway, and extensive remodeling of lipid synthesis pathways including shifts in PC/PE content, increased lysophospholipid production, and altered mitochondrial lipid composition (decreased cardiolipin and increased PG). To identify genetic drivers of STP938 resistance and synthetic lethal vulnerabilities, we performed a genome-wide CRISPR knockout screen together with a PRISM drug sensitivity screen. Genes regulating dNTP biosynthesis, S-phase progression, and RNA processing were identified as primary escape mechanisms, while DHODH inhibitors, purine and nucleoside analogs, and mitosis modifiers were implicated as synthetic lethal opportunities. Notably, we discovered that 25% of ovarian tumors lack CTPS2 protein expression, suggesting near complete reliance on CTPS1 for survival. Thus, a Phase 1a/b clinical trial of STP938 (NCT06297525) has been initiated, including an expansion cohort for patients with CTPS2-null ovarian tumors. These laboratory discoveries and ongoing clinical efforts aim to enable broader uptake of this novel therapeutic approach to improve long-term outcomes in patients with CTPS1-dependent disease. Citation Format: Xiyin Wang, Michael Emch, Lauren Voll, Rebecca Epp, Esther Rodman, Noa Odell, Hannah Smith, Nicole Pearson, Xiaonan Hou, Matthew Goetz, Scott Kaufmann, S. John Weroha, Phillip Beer, John Hawse. CTPS1 as a metabolic vulnerability and novel therapeutic target in breast and ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 4560.

Abstract Breast cancer accounts for nearly a quarter of all cancers in women with an estimated 2.3 million new diagnoses and over 670,000 deaths annually. Triple-negative breast cancer (TNBC) is an aggressive subtype characterized by lack of estrogen receptor alpha (ERα) and progesterone receptor (PR) expression in the absence of HER2 amplification. TNBC accounts for ∼15% of all incident breast cancers and is associated with poor patient outcomes. Problematically, TN tumors exhibit vast inter-patient molecular heterogeneity making the identification of novel therapeutic vulnerabilities difficult and the development of alternative treatment strategies problematic. We and others have demonstrated that estrogen receptor beta (ERβ) is expressed in about 20% of TN tumors and potently suppresses proliferation, invasion, and migration in TNBC cells in vitro and in vivo. We thus hypothesized that endocrine therapies that selectively activate ERβ would be an effective treatment approach for this subset of patients. We also anticipated that some tumors would display de novo or acquired resistance to ERβ targeted therapies despite ERβ protein expression. We therefore sought to define mechanisms of resistance to ERβ targeted therapy and to identify synthetic lethal vulnerabilities. We generated the first models of ERβ resistant TNBC through chronic exposure to estradiol or an ERβ specific agonist (LY500307) and through a CRISPR genome wide knockout screen. We identified the LncRNA XIST as one of the most upregulated transcripts in multiple models of ERβ resistant disease, and knockdown of XIST expression was shown to resensitize resistant cell to estradiol and LY500307 treatment. XIST was not found to be directly regulated by ERβ in TNBC further suggesting that its overexpression is a bona fide mechanism of resistance to ERβ mediated suppression of proliferation. The phenomena of chronic ligand exposure leading to activation of XIST expression in ERβ+ cells is not shared with ERα suggesting that the mechanism by which XIST expression is elevated during the development of resistance is distinct between the two sister receptors. We further characterized XIST expression in patient samples of TNBC and found that XIST expression varies, but largely exhibits a bimodal distribution with most tumors displaying either low or high transcript levels. In conclusion, we have identified the X-inactivating transcript as a driver of resistance to ERβ targeted therapies in TNBC. Future studies aimed at uncovering the consequences of XIST over-expression on global gene expression, functionality of ERβ, and aggressiveness of TNBC are ongoing. Citation Format: Michael Emch, Kirsten Aspros, Matthew P. Goetz, John Hawse. The LncRNA XIST mediates resistance to estrogen receptor beta targeted therapies in triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 2293.

Abstract Introduction: Early relapse limits durable remissions in multiple myeloma (MM). Cell-free DNA (cfDNA) fragment patterns capture tumor burden and nucleosome positioning. We tested whether a fragmentomics signature trained at MRD time points stratifies progression-free survival (PFS) when applied to pretreatment plasma. Methods: We performed 30-40× whole-genome sequencing of plasma cfDNA from 43 newly diagnosed MM patients, with 65 additional MRD timepoint samples from 41 of those patients (post-ASCT n=30; 1-year maintenance n=30; other maintenance n=5) across eight Canadian sites (TFRIM4 and IMMAGINE studies) and one U.S. site (Mayo SPORE). MRD testing used multiparameter flow cytometry for all follow-up samples (n=65) and clonoSEQ in a subset (n=31). Logistic and elastic-net models were trained at MRD timepoints on fragmentomics features (short-fragment burden; a combined model integrating fragment-length distributions with inferred nucleosome positioning at MM-specific chromatin accessibility regions [Ordoñez et al., Genome Res. 2020]). A decision threshold was fixed by the Youden index during training and applied unchanged to diagnosis samples. PFS was analyzed by Kaplan-Meier, log-rank, and Cox models. Results: After a median follow-up of 49.1 months, 16 of 43 patients (37%) progressed. Using the prespecified locked threshold, patients classified as MRD+ by the proportion-of-short-fragments model had significantly shorter PFS than MRD- patients (HR = 5.12; 95% CI 1.16-22.57; log-rank p = 0.016), with median PFS of 49.2 months for MRD+ cases versus not reached for the MRD- group. Fixed-horizon PFS favored MRD- samples at 24/36/48 months (100/94/87% vs 85/81/53% for MRD+). A combined model integrating weighted fragment lengths with inferred nucleosome positioning also separated outcomes (log-rank p=0.054); the Cox HR was not estimable because no MRD- patients relapsed. At 24, 36, and 48 months, baseline MRD positivity by the short-fragment model identified 100%, 83%, and 86% of patients who relapsed within those intervals (specificity 44%, 43%, and 52%), while the combined model detected all early relapses across the same horizons (specificity 15-21%), indicating consistently high sensitivity but modest specificity for predicting early progression. Conclusions: A cfDNA fragmentomics signature trained at MRD time points stratified PFS when applied to diagnostic plasma, identifying patients at risk of early relapse. Short-fragment burden was most discriminative, and a combined model with nucleosome positioning recapitulated it with higher sensitivity, albeit lower specificity. These data support cfDNA fragmentomics as a practical liquid-biopsy risk biomarker in MM and suggest higher signals may proxy aggressive disease with greater tumor shedding and chromatin disorganization. Future work will validate findings in larger cohorts and integrate cytogenetic and immune features. Citation Format: Dor David Abelman, Jenna Eagles, Aimee Wong, Saumil Shah, Jeffrey Bruce, Stephanie Pedersen, David S. Scott, Cecilia Bonolo de Campos, Signy Chow, Darrell White, Irwindeed Sandhu, Kevin Song, Esteban Braggio, Shaji Kunnathu Kumar, Alli Murugesan, Tony Reiman, A. Keith Stewart, Suzanne Trudel, Trevor J. Pugh. Baseline cfDNA fragmentomics identifies multiple myeloma patients at risk of early progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 2597.