Citations

Abstract The primary objective is to evaluate the potential dosimetric gains of performing functional avoidance‐based proton treatment planning using 4DCT derived ventilation imaging. 4DCT data of 31 patients from a prospective functional avoidance clinical trial were evaluated with intensity modulated proton therapy (IMPT) plans and compared with clinical volumetric modulated arc therapy (VMAT) plans. Dosimetric parameters were compared between standard and functional plans with IMPT and VMAT with one‐way analysis of variance and post hoc paired student t‐test. Normal Tissue Complication Probability (NTCP) models were employed to estimate the risk of two toxicity endpoints for healthy lung tissues. Dose degradation due to proton motion interplay effect was evaluated. Functional IMPT plans led to significant dose reduction to functional lung structures when compared with functional VMAT without significant dose increase to Organ at Risk (OAR) structures. When interplay effect is considered, no significant dose degradation was observed for the OARs or the clinical target volume (CTV) volumes for functional IMPT. Using fV20 as the dose metric and Grade 2+ pneumonitis as toxicity endpoint, there is a mean 5.7% reduction in Grade 2+ RP with the functional IMPT and as high as 26% in reduction for individual patient when compared to the standard IMPT planning. Functional IMPT was able to spare healthy lung tissue to avoid excess dose to normal structures while maintaining satisfying target coverage. NTCP calculation also shows that the risk of pulmonary complications can be further reduced with functional based IMPT.

Abstract Background Colon cancer (CC) incidence in young adults (age 20-49 years), termed early-onset CC (EO-CC), is increasing. Methods Individual patient data on 35 713 subjects with stage III colon cancer from 25 randomized studies in the Adjuvant Colon Cancer ENdpoint database were pooled. The distributions of demographics, clinicopathological features, biomarker status, and outcome data were summarized by age group. Overall survival, disease-free survival, time to recurrence, and survival after recurrence were assessed by Kaplan-Meier curves and Cox models stratified by treatment arms within studies, adjusting for sex, race, body mass index, performance status, disease stage, grade, risk group, number of lymph nodes examined, disease sidedness, and molecular markers. All statistical tests were 2-sided. Results Using a 5% difference between age groups as the clinically meaningful cutoff, patients with stage III EO-CC had similar sex, race, performance status, risk group, tumor sidedness, and T stage compared with patients with late-onset CC (age 50 years and older). EO-CC patients were less likely to be overweight (30.2% vs 36.2%) and more commonly had 12 or more lymph nodes resected (69.5% vs 58.7%). EO-CC tumors were more frequently mismatch repair deficient (16.4% vs 11.5%) and less likely to have BRAFV600E (5.6% vs 14.0%), suggesting a higher rate of Lynch syndrome in EO-CC. Patients with EO-CC had statistically significantly better overall survival (hazard ratio [HR] = 0.81, 95% confidence interval [CI] = 0.74 to 0.89; P < .001), disease-free survival (HR = 0.91, 95% CI = 0.84 to 0.98; P = .01), and survival after recurrence (HR = 0.88, 95% CI = 0.80 to 0.97; P = .008) in the analysis without molecular markers; however, age at onset of CC lost its prognostic value when outcome was adjusted for molecular markers. Conclusion Tumor biology was found to be a more important prognostic factor than age of onset among stage III colon cancer patients in the Adjuvant Colon Cancer ENdpoint database.

Transforming growth factor (TGF)‐b signaling in naïve T cells induces expression of transcription factor Foxp3, a master regulator in the regulatory T cells (Tregs). However, the molecular mechanisms leading to Foxp3 induction remain unclear. Here we show that Itch−/− T cells are resistant to TGF‐b treatment with reduced Foxp3 expression. The E3 ubiquitin ligase Itch associates with and promotes ubiquitin conjugation to TGF‐b inducible early gene1 product (TIEG1). More importantly, Itch cooperates with TIEG1 to induce Foxp3 expression, which is reversed by TIEG1 deficiency. Functionally TGF‐b‐converted Tregs generated from TIEG1−/− mice are unable to inhibit naïve T cell proliferation in vitro and suppress airway inflammation in vivo. The results suggest an ubiquitin‐dependent non‐proteolytic pathway that is critical for Foxp3 expression and regulation of allergic responses.

Abstract Basilar artery occlusions (BAOs) are devastating ischemic strokes that account for 1% of all strokes with high morbidity and mortality; however, neuroendovascular techniques such as ADAPT have recently revolutionized the clinical outcomes of these patients. 1-3 Common underlying pathology in patients with BAO include intracranial atherosclerotic disease (ICAD) as well as thromboembolic origin. 4 Basilar artery ICAD in a setting of acute stroke portends a poor prognosis and post-thrombectomy residual critical flow limiting stenosis treatment options, including balloon angioplasty with or without stent placement. 5-7 We present a video illustration of neuroendovascular technique and challenges encountered when managing this pathology. Image at 5:42 reprinted with permission from Alawieh et al, Lessons learned over more than 500 stroke thrombectomies using ADAPT with increasing aspiration catheter size, Neurosurgery , 86(1), 2020, pp. 61-70, with permission from the Congress of Neurological Surgeons. 1

Abstract In-stent stenosis has a reported prevalence of 14% to 19% at 1-yr follow-up after carotid stenting and is associated with an increased risk of acute ischemic stroke. 1,2 Risk factors include female sex, diabetes, and dyslipidemia. Cutting balloon angioplasty is a safe and effective treatment modality for the treatment of carotid in-stent stenosis, and alternative treatment options include observation with medical management and placement of another stent. 3,4 The authors present the case of a 61-yr-old man with carotid in-stent restenosis and progressive worsening on serial imaging with ultrasound. The patient had a history of carotid stenting for symptomatic stenosis 6 mo prior and was maintained on aspirin and clopidogrel. In light of the progressive worsening, the in-stent stenosis was confirmed on computed tomography (CT) angiogram. The options were discussed with the patient and he consented for treatment with cutting balloon angioplasty. Final angiogram showed improvement of the luminal diameter with a residual stenosis of 15%. The patient tolerated the procedure well and was discharged home on postoperative day 1. Follow-up ultrasound demonstrated moderate improvement in peak systolic velocities, and the plan is to continue observation with a clinical follow-up and repeat carotid Dopplers at 3 mo.

11523 Background: Sarcoma pts often receive aggressive, highly immunosuppressive therapy and may be at high risk for severe COVID-19. Demographics, outcomes and risk factors for pts with sarcoma and COVID-19 are unknown. We aimed to describe the course of COVID-19 in sarcoma pts and to identify factors associated with adverse outcomes. Methods: The COVID-19 and Cancer Consortium (NCT04354701) is an international registry of pts with cancer and COVID-19. Adult pts (≥18 years old) with a diagnosis of sarcoma and laboratory confirmed SARS-CoV-2 were included from 50 participating institutions. Data including demographics, sarcoma diagnosis and treatment, and course of COVID-19 infection were analyzed. Primary outcome was the composite rate of hospitalization or death at 30 days from COVID-19 diagnosis. Secondary outcomes were 30 day all-cause mortality, rate of hospitalization, O2 need, and ICU admission. Descriptive statistics and univariate Fisher tests are reported. Results: From March 17, 2020 to February 6, 2021, N=204 pts were included. Median follow up was 42 days. Median age was 58 years (IQR 43-67). 97 (48%) were male. 30 (15%) had ECOG performance status ≥2. 104 (51%) received cancer treatment, including surgery or radiation, within 3 months of COVID-19 diagnosis. 153 (75%) had active cancer, of whom 34 (22%) had lung metastases. 100 (49%) pts met the composite primary endpoint; 96 (47%) were hospitalized and 18 (9%) died within 30 days from COVID-19 diagnosis. 64 (31%) required oxygen, and 16 (8%) required ICU admission. Primary endpoint rates were similar for pts who received cytotoxic chemotherapy (38/58, 66%) or targeted therapy (16/28, 57%). Pts with higher rates of the primary endpoint included patients ≥60 years old (59% vs 40%, OR 2.04, 95% CI 1.12-3.74, p=0.016), pts with ECOG PS ≥2 vs 0-1 (90% vs 41%, OR 12.2, 95% CI 3.44-66.8, p<0.001), pts receiving any systemic therapy within 3 months of COVID-19 diagnosis (62% vs 39%, OR 2.65, 95% CI 1.43-4.97, p=0.001), and pts with lung metastases (68% vs 42%, OR 2.77, 95% CI 1.19-6.79, p=0.013). Primary endpoint rates were similar across sarcoma subtypes (Table). Conclusions: This is the largest cohort study of pts with sarcoma and COVID-19 to date. Sarcoma pts have high rates of complications from COVID-19. Older patients, those with poor performance status, those recently receiving systemic cancer therapy, and those with lung metastases appear to have worse outcomes.[Table: see text]

4100 Background: Checkpoint inhibition with anti-PD1 is able to elicit objective response rates (ORR) of ̃ 20% in patients with advanced hepatocellular carcinoma (aHCC) but molecular biomarkers predicting response remain unknown. Here, we define biomarkers of response and primary resistance to anti-PD1 in aHCC by analyzing molecular features prior to systemic therapy. Methods: Through an international consortium of 13 referral centers, we gathered 111 fresh and archived tumor samples from patients with advanced HCC treated with single agent anti- PD1 therapy. Genomic analysis was performed with whole genome expression arrays, CTNNB1 exon 3 mutation assessment and histological evaluation. Results: Overall, we performed transcriptomic analysis in 83 patients, 28 of which were treated in first-line (ORR: 42.9%) while the remaining 55 patients were treated either in 2nd (41 patients, ORR 29.3%) or 3rd line (14 patients, ORR 7.1%) after prior therapy with tyrosine- kinase inhibitors (TKI) sorafenib or lenvatinib. In patients treated in frontline, response was associated with a significant upregulation in Interferon-γ signaling (IFNγ) and genesets relatedto the antigen presentation machinery (FDR < 0.05). Through differential expression analysis we defined an 11-gene signature that was significantly associated with both major pathways (FDR < 0.01) and was capable of predicting OR as well as progression-free- (PFS) and overall survival (OS) in patients with aHCC. The signature was validated in three independent cohorts of melanoma, lung cancer, and head and neck squamous cell cancer patients were high expression was associated with a significant increase in ORR and longer PFS. In HCC, high expression of the signature was associated with a distinct profile in the immune infiltrate, where an increase in M1 macrophages (p = 0.003), CD4 memory T cell (p < 0.01) and CD4 naïve T cell-infiltration (p = 0.026) was observed. Conversely, low expression of the signature was associated with a marked upregulation of regulatory T cells (p < 0.001). No association was found, however, between either the overall immune infiltrate or CTNNB1 mutations and response. In patients that were treated with TKIs in frontline before receiving subsequent anti-PD1 therapy, the signature was no longer able to predict either OR or PFS/OS, suggesting that TKIs may reshape the microenvironment in a way that renders previously inflamed tumors no longer amenable to anti-PD1. Conclusions: Here, we define an 11-gene signature of response to anti-PD1 in first line aHCC. The signature was validated in patients with other solid cancer types, where it retained its predictive ability. Of note, the signature was not able to identify responders among HCC patients that were treated with TKIs prior to anti-PD1 therapy. The molecular changes induced by different treatment lines would, thus, require fresh biopsies prior to anti-PD1to enable biomarker-driven treatment.

3597 Background: Colon cancer (CC) incidence and mortality have decreased since the 1970s, but the incidence in young adults (20-49 years) is increasing. There are limited data suggesting that, as a group, patients with early onset CRC (eoCC) may have different phenotypic characteristics compared to those with late onset CRC (loCC, age ≥ 50 years). Methods: Individual patient data on 35,713 subjects with stage III CC from 25 randomized studies (recruiting between 1987 and 2009) in the ACCENT database were pooled. The distributions of demographics, clinicopathological features, biomarkers, and outcome data were summarized by age group. Overall survival (OS), disease-free survival (DFS), recurrence free rate (RFR), and survival after recurrence (SAR) were assessed by Kaplan-Meier curves and Cox models stratified by treatment arms within studies, adjusting for gender, race, body mass index, performance status, disease stage, grade, risk group, number of lymph nodes examined, disease sidedness and molecular markers. Results: Using a 5% difference between age groups as the clinically meaningful cutoff, patients with stage III eoCC (n = 6246) had similar distributions according to gender, race, PS, risk group, tumor sidedness and T/N stage compared to those with loCC (n = 29467). Patients with eoCC were significantly less likely to be overweight (30.2% vs 36.2%) but more commonly had ≥ 12 lymph nodes resected (69.5% vs 58.7%). The eoCC tumors were more frequently mismatch repair deficient (16.4% vs 11.5%), and less likely to have BRAFV600E (5.6% vs 14.0%), suggesting a higher frequency of Lynch syndrome in eoCC. In univariate analysis, patients with stage III eoCC had significantly better OS, DFS, and SAR; the difference between 3-year DFS and RFR strongly suggests the OS/DFS difference between these the eoCC and loCC may be due to increased competing risks and comorbidities in patients with loCC. In multivariate analysis, age at onset lost its prognostic value when outcome was adjusted for molecular markers. The clear relation between age of onset and KRAS/BRAF status was confirmed in the interaction analysis. Conclusions: Tumor biology was an important determinant of prognosis regardless of patient age. In multivariate analysis age of onset was not a statistically significant determinant of outcome.[Table: see text]

When COVID-19 caused worldwide cancellations of summer research immersion programs in 2020, Mayo Clinic rallied to create an alternate virtual experience called Summer Foundations in Research (SFIR). SFIR was designed not only to ensure the continuance of science pathways training for undergraduate scientists but also to support undergraduate mental wellbeing, given the known pandemic stressors. A total of 170 participants took part in the program and were surveyed pre-post for outcomes in biomedical research career knowledge, biomedical research career interest, research skills confidence, and three dimensions of mental wellbeing. Knowledge of and interest in careers involving biomedical research rose significantly following participation in SFIR. The participants’ mean research skills confidence also rose between 0.08 and 1.32 points on a 7-point scale across 12 items from the Clinical Research Appraisal Inventory. Success in science pathways support was accompanied by positive shifts in participant mental wellbeing. Measurable decreases in stress (Perceived Stress Scale, p < 0.0001) accompanied gains in resilience (Brief Resilience Scale, p < 0.0001) and life satisfaction (Satisfaction with Life Scale, p = 0.0005). Collectively, the data suggest that core objectives of traditional in-person summer research programming can be accomplished virtually and that these programs can simultaneously impact student wellbeing. This theoretical framework is particularly salient during COVID-19, but the increased accessibility of virtual programs such as SFIR can continue to bolster science education pathways long after the pandemic is gone.