Multi-institutional Study Research Articles

A prospective 10-year follow-up study after sublobar resection for ground-glass opacity-dominant lung cancer

This single-arm multi-institutional prospective study aimed to evaluate the 10-year outcomes of sublobar resection for small-sized ground-glass opacity-dominant lung cancer. Among 73 patients prospectively enrolled from 13 institutions between November 2006 and April 2012, 53 ground-glass opacity-dominant lung cancer patients underwent sublobar resection with wedge resection as the first choice. The inclusion criteria were maximum tumor size of 8–20 mm; ≥ 80% ground-glass opacity ratio on high-resolution computed tomography; lower 18F-fluorodeoxyglucose accumulation than the mediastinum; intraoperative pathological diagnosis of adenocarcinoma in situ; and no cancer cells on intraoperative cut margins. The primary endpoint was a 10-year disease-specific survival. The 53 eligible patients had a mean tumor size of 14 ± 3.4 mm and a mean ground-glass opacity ratio of 95.9 ± 7.2%. Wedge resection and segmentectomy were performed in 39 and 14 patients, respectively. The final pathological diagnoses were adenocarcinoma in situ in 47 patients (88.7%) and adenocarcinoma with mixed subtype in 6 patients (11.3%). The 10-year disease-specific survival and overall survival were 100% and 96.2%, respectively, during a median follow-up period of 120 months (range, 37–162 months). Ground-glass opacity-dominant small lung cancer is cured by sublobar resection when patients are strictly selected by the inclusion criteria of this study.

Prediction of H3K27M alteration in midline gliomas of brain using radiomics- A multi-institute study

Abstract Background Non-invasive prediction of H3K27M-altered Diffuse midline gliomas is important because of the involvement of deep locations and proximity to eloquent structures. We aim to predict H3K27M alteration in midline gliomas using radiomics features of T2W images. Methods Radiomics features extracted from 124 subjects (69 H3K27M-altered/55 H3K27M-wildtype). T2W-images were resampled to 1x1x1mm voxel-size, pre-processed, and normalized for artefact correction, intensity variations. Feature-set was normalized, subjected to reduction by variance thresholding, correlation coefficient thresholding, and sequential feature selector. Adaptive synthesis oversampling technique was used to over-sample the training data. Random forest classifier (RFC), Decision tree classifier (DTC) and K-nearest neighbors classifier (KNN) were trained over the training dataset and the performance was assessed over the internal test dataset and external test data set (52 subjects: 33 H3K27M-altered/19-H3K27M-wildtype). Results DTC achieved validation score of 77.33% (5-fold cross-validation) and accuracy of 80.64%, 75% on internal and external test dataset. RFC achieved validation score of 80.7% (5-fold cross-validation) and accuracy of 80.6%, 73% on internal and external test dataset. DTC achieved validation score of 78.67% (5-fold cross-validation) and accuracy of 80.64%, 61.53% on internal and external test dataset. Accuracy score of DTC, RFC, and KNN on internal test dataset was approximately 80% while on the external test dataset, DTC achieved 75% accuracy, RFC achieved 73% accuracy and KNN achieved 65.1% accuracy. Conclusion H3K27M alteration is a potential immunotherapeutic marker and is associated with poor prognosis and radiomics features extracted from conventional T2W-images can help in identifying H3K27M-altered cases non-invasively with high precision.

Perfusion Strategies for Cytoreductive Surgery With Heated Intraperitoneal Chemotherapy for Malignant Peritoneal Mesothelioma.

Cytoreductive surgery (CRS) with heated intraoperative intraperitoneal chemotherapy (HIPEC) has been shown to improve survival for patients with malignant peritoneal mesothelioma (MPM). Presently, there is no standardized HIPEC protocol with respect to chemotherapeutic agent, dose, administration temperature, or duration and limited literature comparing outcomes in different regimens. In this study, we analyze common practices and outcomes of published HIPEC regimens to gain insight into current practice to inform future directions of study. We conducted a literature search for investigational studies of CRS and HIPEC for MPM treatment in adults and identified 35 such articles. These studies were analyzed for institution type and location, drug regimens, perfusion temperatures and time, and study outcomes including median survival, complication rates, and perioperative mortality rates. On review, there is significant heterogeneity in HIPEC regimens and outcome reporting metrics, suggesting a need for multi-institutional standardized study protocols to better determine the safest and most efficacious treatment regimen.

TERT promoter mutations and additional molecular alterations in thyroid fine-needle aspiration specimens: A multi-institutional study with histopathologic follow-up

Abstract Objectives TERT promoter mutations are not infrequently encountered in thyroid carcinomas; however, it is unclear if additional molecular alterations may play a role in determining tumor behavior. Methods Fine-needle aspiration (FNA) specimens from 32 patients with TERT promoter mutations detected by ThyroSeq v3 from 4 institutions were included in the study. FNA diagnoses, molecular results, and surgical follow-up were retrospectively reviewed and analyzed. Results There were 5 benign and 27 malignant neoplasms, including 7 high-grade thyroid carcinomas (HGCs) on histopathologic follow-up. Of 4 cases with an isolated TERT mutation, 3 (75%) cases were malignant. Of 17 cases harboring a co-occurring TERT mutation with 1 additional molecular alteration, 13 (76%) displayed malignancy on histopathologic follow-up. All 11 cases with TERT mutations plus 2 or more additional molecular alterations were malignant on follow-up. Furthermore, HGC was not seen in cases with an isolated TERT mutation, while 80% of cases harboring TERT mutations plus 3 additional molecular alterations showed HGC. Conclusions TERT promoter mutations are commonly associated with malignancy, particularly HGCs, when multiple co-occurring molecular alterations are present. However, TERT promoter mutations may occasionally be detected in benign thyroid neoplasms when encountered in isolation or with fewer than 2 additional molecular alterations.

Angiomyolipomatous Lesions of the Nasal Cavity (Sinonasal Angioleiomyoma with Adipocytic Differentiation): A Multi-Institutional Immunohistochemical and Molecular Study.

Mesenchymal neoplasms composed of vascular, smooth muscle, and adipocytic components are uncommon in the nasal cavity. While angioleiomyoma (AL) is a smooth muscle tumor in the Head & Neck WHO classification, it is considered of pericytic origin in the Skin as well as Soft Tissue and Bone classifications. For nasal AL with an adipocytic component, the terms AL with adipocytic differentiation and angiomyolipoma (AML) have been applied, among others. AML is a type of perivascular epithelioid cell tumor (PEComa), most often arising in the kidney, sometimes associated with the tuberous sclerosis complex (TSC). It is uncertain whether nasal cavity AML and AL are best considered hamartomas or neoplasms, as their genetics are largely unexplored. We performed a multi-institutional retrospective study of nasal cavity mesenchymal lesions. Patient demographics, clinical histories, and histologic and immunohistochemical findings were collected. DNA and RNA were extracted from formalin-fixed, paraffin-embedded tissue and analyzed by SNP-based chromosomal microarray, targeted RNA fusion sequencing, and whole-exome sequencing. Fifteen lesions (3 to 42 mm) were identified predominantly in male (87%) patients with a median age of 60. Patients typically presented with obstructive symptoms, and none had a history of TSC. One AL was a recurrence from six years prior; 11 cases showed no recurrence (median 4.7 years, range: 0.88-12.4). Morphologically, 11 AMLs contained 30-80% smooth muscle, 10-25% vasculature, and 2-60% adipose tissue, while four ALs contained 70-80% smooth muscle and 20-30% vasculature. Other histologic observations included surface ulceration, vascular thrombosis, chronic inflammation, and myxoid change; no well-developed epithelioid cell morphology was identified. Immunohistochemically, all cases were positive for smooth muscle markers (actin and/or desmin) and negative for melanocytic markers. Molecular analysis revealed loss of 3p and 11q in a single AML. No other known pathogenic copy number or molecular alterations were seen, including in TSC1/2, TFE3, or NOTCH2. Nasal cavity AML lacks morphologic, immunophenotypic, and genetic features of PEComa family AMLs. The significant histologic overlap between nasal AML and AL without distinguishing molecular features in either entity suggests "sinonasal angioleiomyoma with adipocytic differentiation" may be the most appropriate terminology for hybrid vascular and smooth muscle lesions containing adipocytic components.

Treatment Outcomes after Postoperative Radiotherapy in Triple-Negative Breast Cancer: Multi-Institutional Retrospective Study (KROG 17-05).

We designed a multi-institutional retrospective study to investigate the previously unreported failure pattern, survivals, and prognostic factors after postoperative radiotherapy (PORT) in triple negative breast cancer (TNBC) patients in South Korea. We retrospectively reviewed 699 patients with TNBC who underwent PORT at six institutions between 2008 and 2010. The median follow-up period was 94 months (range: 7-192 months). There were 216, 380, and 100 patients in stages I, II, and III, respectively. After 94 months post-treatment, all patients with pathologic complete remission after neoadjuvant chemotherapy were alive without any failure. Distant metastasis was the main cause of failure. The 5-year overall survival rate was 91.4%, 5-year loco-regional relapse-free survival rate (LRRFS) was 92.3%, 5-year distant metastasis-free survival rate (DMFS) was 89.4%, and 5-year disease-free survival rate (DFS) was 85.2%. On multivariate (Cox) analysis, T and N stages were significant prognostic factors for survival, and lympho-vascular invasion (LVI) was a significant factor for LRRFS and DMFS. Ki-67 expression was significantly associated with LRRFS and DFS. We verified that T and N stages, LVI, and Ki-67 expression were significantly associated with survival outcomes after PORT in TNBC.

A Multi-Institutional Study of Magnetic Resonance/Ultrasound Fusion-Guided Nanoparticle-Directed Focal Therapy for Prostate Ablation.

Focal therapy aims to provide a durable oncologic treatment option for men with prostate cancer (PCa), while preserving their quality of life. Most focal therapy modalities rely on the direct tissue effect, resulting in a possible nontargeted approach to ablation. Here, we report the results of the first human feasibility trial utilizing nanoparticle-directed focal photothermal ablation for PCa. A prospective, open-label, single-arm, multicenter study of men with localized PCa in Gleason Grade Group 1 to 3 was conducted. Men received a single infusion of gold nanoparticles (AuroShells), followed by magnetic resonance (MR)/ultrasound (US) fusion-guided laser excitation of the target tissue to induce photothermal ablation. MRI was used to assess the effectiveness of prostate tissue ablation at 48 to 96 hours, 3 months, and 12 months post treatment. At 3 months, a targeted fusion biopsy of the lesion(s) was conducted. At 12 months, a targeted fusion biopsy and standard templated biopsy were performed. Treatment success was determined based on a negative MR/US fusion biopsy outcome within the treated area. Forty-six men were enrolled in the study, and 44 men with 45 lesions completed nanoparticle infusion and laser treatment. The mean PSA level at baseline was 9.5 ng/mL, which decreased to 5.9 ng/mL at 3 months and to 4.7 ng/mL at 12 months (P < .0001). The oncologic success rates at 3 and 12 months resulted in 29 (66%) and 32 (73%) of 44 patients, respectively, being successfully treated, confirmed with negative MR/US fusion biopsies within the ablation zone. Among Gleason Grade Group, maximum lesion diameter on MRI, prostate volume, and Prostate Imaging Reporting and Data System scoring, the maximum lesion diameter was significantly associated with the odds of treatment failure at 12 months (P = .046). Nanoparticle-directed focal laser ablation of neoplastic prostate tissue resulted in 73% of patients with successful treatment at 12 months post treatment, confirmed by negative MR/US fusion biopsy of the treated lesion and a systematic biopsy. 02680535.

Clinical outcomes of first-line combination therapy with immune checkpoint inhibitor for metastatic non-clear cell renal cell carcinoma: a multi-institutional retrospective study in Japan.

In metastatic clear cell renal cell carcinoma (ccRCC), recent studies have shown promising efficacy of immune checkpoint inhibitor (ICI) combination therapy. However, there are insufficient evidences about clinical efficacy and safety of ICI combination therapy in metastatic non-ccRCC (nccRCC). We retrospectively investigated 44 patients treated with nivolumab plus ipilimumab (ICI + ICI group) or anti-PD-1/PD-L1 inhibitor plus tyrosine kinase inhibitors (TKI) (ICI + TKI group), and assessed clinical efficacy in both groups. Of all patients, overall response rate and disease control rate for ICI combination treatments were 36.3% and 75%, respectively. The median progression-free survival (PFS) and overall survival (OS) was 8.8 and 23.9months, respectively. Multivariate analysis revealed that the presence of liver metastasis significantly affected worse PFS and OS (p = 0.035 and p = 0.049). Importantly, PFS and OS seemed similar in ICI + ICI group and ICI + TKI group (p = 0.778 and p = 0.559). Although the discontinuation rate of the combination therapy due to adverse effects in patients aged ≥ 75years was significantly higher compared to that in patients aged < 75years (45% versus 12%, p = 0.017), there were no significant differences in PFS and OS between two groups (p = 0.290 and p = 0.257, respectively). This study confirms clinical benefit of ICI combination therapy for metastatic nccRCC patients in real-world settings. Furthermore, the effectiveness of combination therapy was comparable between patients aged < 75 and those ≥75years with respect to clinical prognosis.

A Multi-Institutional Study from the US ROPE Consortium Examining Factors Influencing Vascular Surgery Specialization among General Surgery Residents

There remains a progressive projected deficit in the vascular surgery (VS) workforce for decades yet to come. Despite the rise of an expanding integrated VS residency pathway, the fellowship training model remains critical in supporting our future workforce. Therefore, it is imperative to understand the resident and program-specific factors that influence VS specialization among general surgery (GS) residents. Data from the US Resident OPerative Experience (ROPE) Consortium, comprising 20 Accreditation Council for Graduate Medical Education (ACGME)-accredited GS residency programs across the United States, were queried for resident demographics and residency program-related details. Logistic regression analysis was used to identify factors associated with VS specialization. From 2010 to 2020, a total of 1343 graduating GS residents were included in the study. Of these, 135 (10.1%) pursued VS fellowship training. Residents pursuing VS were more frequently male (80.7% vs 62.8%, p<0.0001) and younger (median 32 vs 33 yr, p=0.03) compared with other GS residents. Racial and ethnic group, underrepresented in medicine (URiM) status, and international medical graduate (IMG) status were similar between VS and non-VS groups. Residency program-level details were also similar between groups, including program type (university vs community-based), region, size, resident volume, dedicated research experience, and National Institutes of Health funding. Dedicated vascular rotations were common among all GS programs (95.4%), and total months spent on a VS rotation (median 4 vs 4.5 mo, p=0.11) did not differ among residents pursuing VS and all other residents. The presence of a collocated traditional (5+2) VS fellowship (91.1% vs 90.4%, p=0.79) or integrated (0+5) VS residency (56.3% vs 55.0%, p=0.77) were also similar between groups. On multivariate analysis, only male sex (odds ratio 2.34, 95% confidence interval, 1.50-3.81, p<0.001) was associated with pursuing VS fellowship. Factors that did not impact VS specialization included resident age, URiM status, IMG status, program volume, dedicated research experience, or total months spent on a VS rotation. In this multi-institutional study, we did not find any program-specific factors that influence VS specialization among GS residents. Notably, the presence of a collocated 0+5 residency or 5+2 fellowship program did not appear to deter GS residents from pursuing VS fellowship. These data suggest that individual factors, such as mentorship, may be more impactful in recruiting GS residents to the VS specialty.

NnU-Net-based Segmentation of Tumor Subcompartments in Pediatric Medulloblastoma Using Multiparametric MRI: A Multi-institutional Study.

Purpose To evaluate nnU-Net-based segmentation models for automated delineation of medulloblastoma tumors on multi-institutional MRI scans. Materials and Methods This retrospective study included 78 pediatric patients (52 male, 26 female), with ages ranging from 2 to 18 years, with medulloblastomas, from three different sites (28 from hospital A, 18 from hospital B, and 32 from hospital C), who had data available from three clinical MRI protocols (gadolinium-enhanced T1-weighted, T2-weighted, and fluid-attenuated inversion recovery). The scans were retrospectively collected from the year 2000 until May 2019. Reference standard annotations of the tumor habitat, including enhancing tumor, edema, and cystic core plus nonenhancing tumor subcompartments, were performed by two experienced neuroradiologists. Preprocessing included registration to age-appropriate atlases, skull stripping, bias correction, and intensity matching. The two models were trained as follows: (a) the transfer learning nnU-Net model was pretrained on an adult glioma cohort (n = 484) and fine-tuned on medulloblastoma studies using Models Genesis and (b) the direct deep learning nnU-Net model was trained directly on the medulloblastoma datasets, across fivefold cross-validation. Model robustness was evaluated on the three datasets when using different combinations of training and test sets, with data from two sites at a time used for training and data from the third site used for testing. Results Analysis on the three test sites yielded Dice scores of 0.81, 0.86, and 0.86 and 0.80, 0.86, and 0.85 for tumor habitat; 0.68, 0.84, and 0.77 and 0.67, 0.83, and 0.76 for enhancing tumor; 0.56, 0.71, and 0.69 and 0.56, 0.71, and 0.70 for edema; and 0.32, 0.48, and 0.43 and 0.29, 0.44, and 0.41 for cystic core plus nonenhancing tumor for the transfer learning and direct nnU-Net models, respectively. The models were largely robust to site-specific variations. Conclusion nnU-Net segmentation models hold promise for accurate, robust automated delineation of medulloblastoma tumor subcompartments, potentially leading to more effective radiation therapy planning in pediatric medulloblastoma. Keywords: Pediatrics, MR Imaging, Segmentation, Transfer Learning, Medulloblastoma, nnU-Net, MRI Supplemental material is available for this article. © RSNA, 2024 See also the commentary by Rudie and Correia de Verdier in this issue.

Association Between the Regular Use of Vaginal Dilators and/or Sexual Activity and Vaginal Morbidity in Locally Advanced Cervical Cancer Survivors: An EMBRACE-I Study Report

PurposeTo provide risk estimations for vaginal morbidity with regard to vaginal dilation (summarizing the use of dilators and/or sexual activity) in locally advanced cervical cancer patients (LACC) treated with definitive radiochemotherapy and image-guided adaptive brachytherapy (IGABT) within the prospective, multi-institutional EMBRACE-I study. Material/MethodsPhysician-assessed vaginal morbidity (CTCAEv3.0), use of vaginal dilators and patient-reported sexual activity (EORTC-CX24) were prospectively assessed at baseline and during regular follow-up.Frequency analysis for vaginal dilation was performed in a sub-cohort of patients with ≥3 follow-ups. Regular dilation was defined if reported in ≥50% of follow-ups, no/infrequent dilation if reported in <50%. Actuarial estimates were calculated with Kaplan-Meier method; comparisons evaluated with the log-rank test. Univariate and multivariable Cox proportional hazard regression were used to evaluate risk factors for vaginal stenosis G≥2. ResultsThe EMBRACE-I study included a total of 1416 patients (2008-2015); 882 were evaluated in the present report with a median follow-up of 60 months. Of those, 565 (64%) reported regular dilation. This was associated with a significantly lower 5-year risk of vaginal stenosis G≥2 compared to no/infrequent dilation (23% vs. 37%, p≤0.001). This univariate finding was confirmed by multivariable analysis, after adjusting for other risk factors (HR=0.630, p=0.001).Regular vaginal dilation was also associated with a significantly higher risk for vaginal dryness G≥1 (72% vs. 67%, p=0.028) and bleeding G≥1 (61% vs. 34%, p≤0.001). ConclusionVaginal stenosis represents irreversible fibrotic changes that can cause pain during gynecological examination and dyspareunia in LACC survivors. Regular vaginal dilation (defined as the use of dilators and/or sexual activity) is associated with a significantly lower risk for G≥2 vaginal stenosis, suggesting a potential improvement of vaginal patency. It is also associated with a significantly higher risk for mild G≥1 dryness and bleeding (no higher risk for G≥2), which both can be clinically managed.

Neoadjuvant everolimus in renal angiomyolipoma with or without tuberous sclerosis complex: Results from a multicenter, retrospective study.

To assess the efficacy and safety of preoperative neoadjuvant everolimus in renal angiomyolipomas (AML) patients with or without Tuberous Sclerosis Complex (TSC). This multi-institutional retrospective study enrolled renal AML patients who underwent partial nephrectomy (PN) or total nephrectomy after receiving at least 1 month of pre-operative everolimus. Imaging evaluations were collected before and after treatment, along with demographic, surgical, and follow-up information. The primary outcome was tumor volume reduction of ≥25%, with additional outcomes including recurrence, perioperative outcomes, renal function, and safety. From January 2015 to July 2022, 68 renal AML patients were studied-41 with TSC and 27 without. During everolimus treatment, 61.0% (25/41) of TSC patients and 44.4% (12/27) of non-TSC patients achieved tumor reduction of ≥25%. Additionally, 41.5% (17/41) of TSC patients and 18.5% (5/27) of non-TSC patients achieved a ≥ 50% reduction. Three TSC patients and 1 non-TSC patient discontinued treatment due to side-effects. Most patients (92.7% TSC, 85.2% non-TSC) underwent PN. After everolimus treatment, the necessary total nephrectomy decreased to 41.2% (7/17) from baseline. Postoperatively, 1 grade 3 and 3 grade 2 complications occurred, with no grade 4 or 5 complications. After a median follow-up of 24 months, only 1 TSC patient recurred with a diameter >3 cm. Retrospective nature is the major limitation of this study. Everolimus was effective and well-tolerated in neoadjuvant treatment for renal AML, especially in TSC patients. This neoadjuvant combination strategy of everolimus and PN could effectively controls recurrence and preserves renal function.

Redefining Candidates for Deintensification in Locoregionally Advanced P16+ Oropharyngeal Cancer Based on Relative Risk

Randomized trials have found that patients with locoregionally advanced p16+ oropharyngeal squamous cell carcinoma (OPSCC) do not benefit from treatment deintensification, even among favorable risk groups. Although various methods have been used to identify candidates for treatment deintensification, the optimal approach is unknown. We conducted a multi-institutional cohort study of 444 patients with previously untreated p16+ OPSCC undergoing definitive radiation therapy with or without systemic therapy between 2009 and 2022. We compared the following 2 approaches for identifying candidates for deintensification: (1) favorable versus unfavorable risk, using NRG-HN005 eligibility criteria, and (2) low versus high relative risk of cancer events, using the Head and Neck Cancer Intergroup predictive classifier ("omega score"). We tested differences in outcomes and systemic therapy allocation by risk group using multivariable Cox models, competing event models, and logistic regression, and compared characteristics of hypothetical deintensification trials using the 2 approaches. Progression-free survival events were defined as cancer recurrence (locoregional or distant) or death from any cause. Median follow-up time was 52 months; 120 patients (27.0%) were favorable risk; a different 120 patients had low omega score; 28 patients (6.3%) met both criteria; 184 patients (41.4%) had discordant classification. On ordinal logistic regression, decreasing omega score was associated with a statistically significantly lower odds of receiving intensive therapy (normalized odds ratio, 0.37 per SD; 95% CI, 0.24-0.57), with a greater magnitude than favorable risk group (odds ratio, 0.66; 95% CI, 0.44-0.99). Among patients receiving cisplatin and/or platinum-based induction (n = 374), favorable risk was associated with significantly improved progression-free survival (hazard ratio, 0.59; 95% CI, 0.36-0.99), whereas lower omega score was associated with a significantly decreased relative hazard for cancer events (relative hazard ratio, 0.18; 95% CI, 0.070-0.46). In simulations, selecting patients with low omega scores increased the efficiency of hypothetical noninferiority trials. Considering patients' relative risk of cancer events can help define optimal populations for treatment deintensification in p16+ OPSCC.

304P Impact of estrogen receptor positivity for adjuvant endocrine therapy in luminal T1a/bN0M0 breast cancer: A multi-institutional retrospective observational study

304P Impact of estrogen receptor positivity for adjuvant endocrine therapy in luminal T1a/bN0M0 breast cancer: A multi-institutional retrospective observational study

Multi-Institutional Study of Referral Patterns for Gynecologic Oncology Consultation.

Evaluation by a gynecologic oncologist (GO) is associated with improved clinical outcomes for patients with gynecologic cancers, yet little is known about health care factors that influence patients' referrals to GO. Medical records of 50 consecutive new patients seen in GO clinics at each of six referral centers across the United States were reviewed. Patient and disease characteristics were collected along with referral indication, evaluation and referral dates, diagnostic procedures, provider specialties, and zone improvement plan (ZIP) code of up to three referring providers per patient. The primary outcome was interval between first evaluation and referral. Univariate associations were evaluated with Chi-square and Wilcoxon rank-sum tests and multivariable associations with negative binomial regression models. Secondary outcome was prolonged time to GO referral, defined as greater than the 75th percentile. Logistic regression was used for multivariable modeling. Three hundred patient records were analyzed. The median time from first health care encounter to referral was 15 days (IQR, 5-43). The mean distance from residence to GO was 39.8 miles (standard deviation, 53.8). Seventy-one percent of GO referrals were initiated by obstetrician-gynecologists, 9% by family physicians, and 6% internists. Presentation-to-referral interval was 76% shorter for patients evaluated by an emergency medicine clinician (exp(Beta), 0.24; 95% CI, 0.11 to 0.53; P < .001). Public insurance was associated with 1.47 times longer time to referral compared with private insurance (exp(Beta), 1.47; 95% CI, 1.05 to 2.04; P = .001). Residents of nonmetropolitan ZIP codes were less likely to have prolonged time to referral (odds ratio [OR], 0.288; P = .017). Distance from residence to GO (per 10 miles) increased the likelihood of prolonged time to referral (OR, 1.10; P = .010). Interventions are needed to improve recognition and referral of patients for gynecologic oncology evaluation. Community outreach and engagement with obstetrician-gynecologists should be prioritized to improve times to referral.

52141 Multi-institutional study evaluating efficacy of SPOTS (Sun Protection Outreach Teaching by Students) in adolescent students across the United States

52141 Multi-institutional study evaluating efficacy of SPOTS (Sun Protection Outreach Teaching by Students) in adolescent students across the United States

305P Prognosis of isolated locoregional recurrence after early breast cancer with immediate breast reconstruction surgery: A retrospective multi-institutional study

305P Prognosis of isolated locoregional recurrence after early breast cancer with immediate breast reconstruction surgery: A retrospective multi-institutional study

A multi-institutional study to investigate the sparing effect after whole brain electron FLASH in mice: Reproducibility and temporal evolution of functional, electrophysiological, and neurogenic endpoints

Background and PurposeUltra-high dose-rate radiotherapy (FLASH) has been shown to mitigate normal tissue toxicities associated with conventional dose rate radiotherapy (CONV) without compromising tumor killing in preclinical models. A prominent challenge in preclinical radiation research, including FLASH, is validating both the physical dosimetry and the biological effects across multiple institutions. Materials and MethodsWe previously demonstrated dosimetric reproducibility of two different electron FLASH devices at separate institutions using standardized phantoms and dosimeters. In this study, tumor-free adult female mice were given 10 Gy whole brain FLASH and CONV irradiation at both institutions and evaluated for the reproducibility and temporal evolution of multiple neurobiological endpoints. ResultsFLASH sparing of behavioral performance on novel object recognition (4 months post-irradiation) and of electrophysiologic long-term potentiation (LTP, 5 months post-irradiation) was reproduced between institutions. Differences between FLASH and CONV on the endpoints of hippocampal neurogenesis (Sox2, doublecortin), neuroinflammation (microglial activation), and electrophysiology (LTP) were not observed at early times (48 h to 2 weeks), but recovery of immature neurons by 3 weeks was greater with FLASH. ConclusionIn summary, we demonstrated reproducible FLASH sparing effects on the brain between two different beams at two different institutions with validated dosimetry. FLASH sparing effects on the endpoints evaluated manifested at later but not the earliest time points.

Post-operative Crohn's Disease Recurrence and Infectious Complications: A Transcriptomic Analysis.

Crohn's disease (CD) is a chronic inflammatory condition affecting the gastrointestinal tract, characterized by complications such as strictures, fistulas, and neoplasia. Despite medical advancements, a significant number of patients with Crohn's disease require surgery, and many experience post-operative complications and recurrence. Previous studies have analyzed gene expression to study recurrence and post-operative complications independently. This study aims to identify overlapping differentially expressed genes and pathways for recurrence and post-operative complications. A dataset including 45 patients with Crohn's disease, including gene expression from ileum and colon tissue, endoscopic recurrence, and intra-abdominal septic complications was analyzed. Gene set enrichment analysis was used to identify gene pathways associated with the outcomes. Finally, a multi-variable logistic regression model was created to assess whether gene pathways were independently associated with both outcomes. In ileum tissue, several inflammatory pathways, including interferon alpha and gamma response were upregulated in patients with endoscopic recurrence and intra-abdominal septic complications. In addition, there was upregulation of the epithelial mesenchymal transition pathway. In colon tissue, metabolic processes, such as myogenesis and oxidative phosphorylation were downregulated in both outcomes. In a multivariate model, downregulation of myogenesis in colon tissue was significantly associated with both endoscopic recurrence and intra-abdominal septic complications. These findings shed light on the underlying biology of these outcomes and suggest potential biomarkers or therapeutic targets to reduce their occurrence. Further validation and multi-institutional studies are warranted to confirm these results and improve post-operative outcomes for patients with Crohn's disease.

Effectiveness of Machine Learning in Predicting Orthodontic Tooth Extractions: A Multi-Institutional Study.

The study aimed to evaluate the effectiveness of machine learning in predicting whether orthodontic patients would require extraction or non-extraction treatment using data from two university datasets. A total of 1135 patients, with 297 from University 1 and 838 from University 2, were included during consecutive enrollment periods. The study identified 20 inputs including 9 clinical features and 11 cephalometric measurements based on previous research. Random forest (RF) models were used to make predictions for both institutions. The performance of each model was assessed using sensitivity (SEN), specificity (SPE), accuracy (ACC), and feature ranking. The model trained on the combined data from two universities demonstrated the highest performance, achieving 50% sensitivity, 97% specificity, and 85% accuracy. When cross-predicting, where the University 1 (U1) model was applied to the University 2 (U2) data and vice versa, there was a slight decrease in performance metrics (ranging from 0% to 20%). Maxillary and mandibular crowding were identified as the most significant features influencing extraction decisions in both institutions. This study is among the first to utilize datasets from two United States institutions, marking progress toward developing an artificial intelligence model to support orthodontists in clinical practice.