High Community-Level Social Vulnerability is Associated with Worse Recurrence-Free Survival (RFS) After Resection of Extremity and Truncal Soft Tissue Sarcoma

BACKGROUND

Although social vulnerability has been associated with worse postoperative and oncologic outcomes in other cancer types, these effects have not been characterized in patients with soft tissue sarcoma. This study evaluated the association of social vulnerability and oncologic outcomes.

METHODS

The authors conducted a single-institution cohort study of adult patients with primary and locally recurrent extremity or truncal soft tissue sarcoma undergoing resection between January 2016 and December 2021. The social vulnerability index (SVI) was measured on a low (SVI 1-39%, least vulnerable) to high (60-100%, most vulnerable) SVI scale. The association of SVI with overall survival (OS) and recurrence-free survival (RFS) was evaluated by Kaplan-Meier analysis and Cox proportional hazard regression.

RESULTS

The study identified 577 patients. The median SVI was 44 (interquartile range [IQR], 19-67), with 195 patients categorized as high SVI and 265 patients as low SVI. The median age, tumor size, histologic subtype, grade, comorbidities, stage, follow-up time, and perioperative chemotherapy and radiation utilization were similar between the high and low SVI cohorts. The patients with high SVI had worse OS (p = 0.07) and RFS (p = 0.016) than the patients with low SVI. High SVI was independently associated with shorter RFS in the multivariate analysis (hazard ratio, 1.64; 95% confidence interval, 1.06-2.54) but not with OS (HR, 1.47; 95% CI 0.84-2.56).

CONCLUSION

High community-level social vulnerability appears to be independently associated with worse RFS for patients undergoing resection of extremity and truncal soft tissue sarcoma. The effect of patient and community-level social risk factors should be considered in the treatment of patients with extremity sarcoma.

When to ditch the ladder and take the elevator: The Anderson SArcoma Risk of Complications (A-SARC) score to guide reconstructive decision-making in extremity soft tissue sarcoma patients

BACKGROUND

The reconstructive ladder relies mostly on defect size and depth to determine reconstructive technique, however, in actuality, many more variables ultimately inform reconstructive decision making, especially regarding extremity soft tissue sarcoma (eSTS) defects. The purpose of this study was to describe eSTS patients who will most optimally benefit from an advanced method of reconstruction (defined as a pedicled regional flap or free flap) and to create a simple risk assessment scale that can be employed in clinical practice.

STUDY DESIGN

A single-institution retrospective cohort study examined patients undergoing resection of soft tissue sarcoma affecting the upper or lower extremities between 2016 and 2021. We categorized patients who required a pedicled or free flap as having had advanced reconstruction, and all other techniques were considered simple reconstruction. A regression was used to create a risk scale to guide reconstructive decision-making.

RESULTS

The following variables were identified as independent predictors of complications and used to create our risk scale: lower extremity tumor location, preoperative radiotherapy, tumor bed excision, male sex, hypertension, and tumor volume. Intermediate and high-risk patients reconstructed using simple techniques had significantly greater overall complication rates compared to those reconstructed with advanced techniques. Major complications were significantly greater in low-risk patients reconstructed with advanced techniques.

CONCLUSIONS

To minimize postoperative wound complications, low-risk patients should receive simple methods of reconstruction, whereas high-risk patients should be reconstructed using advanced techniques.

A randomized, non-comparative phase 2 study of neoadjuvant immune-checkpoint blockade in retroperitoneal dedifferentiated liposarcoma and extremity/truncal undifferentiated pleomorphic sarcoma

Based on the demonstrated clinical activity of immune-checkpoint blockade (ICB) in advanced dedifferentiated liposarcoma (DDLPS) and undifferentiated pleomorphic sarcoma (UPS), we conducted a randomized, non-comparative phase 2 trial ( NCT03307616 ) of neoadjuvant nivolumab or nivolumab/ipilimumab in patients with resectable retroperitoneal DDLPS (n = 17) and extremity/truncal UPS (+ concurrent nivolumab/radiation therapy; n = 10). The primary end point of pathologic response (percent hyalinization) was a median of 8.8% in DDLPS and 89% in UPS. Secondary end points were the changes in immune infiltrate, radiographic response, 12- and 24-month relapse-free survival and overall survival. Lower densities of regulatory T cells before treatment were associated with a major pathologic response (hyalinization > 30%). Tumor infiltration by B cells was increased following neoadjuvant treatment and was associated with overall survival in DDLPS. B cell infiltration was associated with higher densities of regulatory T cells before treatment, which was lost upon ICB treatment. Our data demonstrate that neoadjuvant ICB is associated with complex immune changes within the tumor microenvironment in DDLPS and UPS and that neoadjuvant ICB with concurrent radiotherapy has significant efficacy in UPS.

Sarcoma Size and Limb Dimensions Predict Complications, Recurrence, and Death in Patients with Soft Tissue Sarcoma in the Thigh: A Multidimensional Analysis

BACKGROUND

Limb-sparing resections of thigh soft tissue sarcomas (STSs) can result in adverse outcomes. Identifying preoperative predictors for wound healing complications, tumor recurrence, and mortality is crucial for informed reconstructive decision-making. We hypothesized that preoperative measurements of thigh and tumor dimensions could serve as reliable indicators for postoperative complications, recurrence, and death.

PATIENTS AND METHODS

In this retrospective cohort study conducted from March 2016 to December 2021, we analyzed patients undergoing thigh STS excisions followed by reconstruction. Preoperative magnetic resonance imaging or computed tomography scans provided necessary thigh and tumor dimensions. Univariate and multivariate regression assessed relationships between these dimensions and postoperative outcomes, including complications, recurrence, and death.

RESULTS

Upon the analysis of 123 thighs, we found thigh width to be highly predictive of postoperative complications, even surpassing body mass index (BMI) and retaining significance in multivariate regression [odds ratio (OR) 1.19; 95% CI 1.03-1.39; p = 0.03]. Sarcoma-to-thigh width and thickness ratios predicted STS recurrence, with the thickness ratio retaining significance in multivariate regression (OR 1.03; 95% CI 1.001-1.05; p = 0.041). Notably, greater thigh thickness was independently protective against mortality in multivariate analysis (OR 0.80; 95% CI 0.65-0.98; p = 0.030).

CONCLUSIONS

Thigh width outperformed BMI in association with postoperative complications. This may create an opportunity for intervention, where weight loss can play a role during the neoadjuvant therapy period to potentially reduce complications. Sarcoma-to-thigh width and thickness ratios, particularly the latter, hold substantial predictive value in terms of STS recurrence. Moreover, thigh thickness is an independent predictor of survival.

Identifying risk factors and analyzing reconstructive outcomes in patients with lower-extremity soft-tissue sarcoma

PURPOSE

Reconstructing defects after resecting soft-tissue sarcoma (STS) can be challenging. The aim of this retrospective study was to analyze the reconstructive outcomes and identify the potential risk factors in patients undergoing reconstruction after excision of lower-extremity STS.

METHODS

Patients with lower-extremity STS were included. This database was compiled of patients from a single, large National Cancer Institute-accredited academic hospital. In total, 302 patients were included between January 2016 to January 2022. Univariate and multivariate analyses were performed to calculate odds ratios (ORs) for developing complications for each patient and surgical characteristic.

RESULTS

The following factors were independent predictors of any complication: benign pulmonary disease (OR = 4.2; p = 0.02), preoperative radiotherapy (RT; OR = 2.5; p = 0.047), a tumor in the medial thigh (OR = 1.9; p = 0.03), body mass index (BMI) > 30 kg/m2 (OR = 1.05; p = 0.037), and full-thickness skin graft (OR = 5.4; p = 0.01). In the preoperative RT subgroup, reconstructing a defect via undermining and layered closure alone was an independent predictor of dehiscence (OR = 2.1; p = 0.02) and seroma (OR = 3.1; p = 0.02), whereas pedicled flaps (OR = 0.08; p = 0.001) and free flaps (OR = 0.05; p = 0.001) were independent protectors against any complication.

CONCLUSION

Information derived from this analysis will assist with accurate preoperative patient counseling, which is crucial for informed decision-making and expectation management in lower-extremity STS. BMI and pulmonary function should be optimized to the extent possible to reduce postoperative complications. Patients treated preoperatively with RT should be reconstructed with a pedicled or free flap to optimize recovery.

Development of a Novel Comprehensive Hepatocellular Carcinoma Outcome Prognostic Scoring System With Integration of Imaging Features

BACKGROUND

Accurate prognostic stratification of hepatocellular carcinoma (HCC) is vital for clinical trial enrollment and treatment allocation. Multiple scoring systems have been created to predict patient survival, but no standardized scoring systems account for radiologic tumor features. We sought to create a generalizable scoring system for HCC which incorporates standardized radiologic tumor features and more accurately predicts overall survival (OS) than established systems.

METHODS

Clinicopathologic parameters were collected from a prospectively collected cohort of patients with HCC treated at a single institution. Imaging studies were evaluated for tumor characteristics. Patients were randomly divided into a training set for identification of covariates that impacted OS and a validation set. Cox models were used to determine the association of various factors with OS and a scoring system was created.

RESULTS

We identified 383 patients with HCC with imaging and survival outcomes, n = 255 in the training set and 128 in the validation cohort. Factors associated with OS on multivariate analysis included: tumor margin appearance on CT or MRI (hazard ratio [HR] 1.37, 95% CI, 1.01-1.88) with infiltrative margins portending worse outcomes than encapsulated margins, massive tumor morphology (HR 1.64, 95% CI, 1.06-2.54); >2 lesions (HR 2.06, 95% CI, 1.46-2.88), Child-Turcotte-Pugh class C (HR 3.7, 95% CI, 2.23-6.16), and portal vein thrombus (HR 2.41, 95% CI, 1.71-3.39). A new scoring system was developed and more predictive of OS than other well-established systems.

CONCLUSIONS

Incorporation of standardized imaging characteristics to established clinical and lab predictors of outcome resulted in an improved predictive scoring system for patients with HCC.

Primary tumor site for localized Merkel cell carcinoma drives different management strategies without impacting oncologic outcomes

BACKGROUND AND PURPOSE

Clinically localized Merkel cell carcinoma (MCC) has been associated with high rates of disease relapse. This study examines how primary tumor anatomic site drives patterns of care and outcomes in a large cohort treated in the contemporary era.

MATERIALS AND METHODS

Patterns of care and associated outcomes were evaluated for clinically Stage I-II MCC patients treated at our institution with adjuvant radiation therapy (RT) to the primary site and/or regional nodal basin as a component of their curative intent therapy between 2014-2021.

RESULTS

Of 80 patients who met inclusion criteria, the primary tumor anatomic site was head and neck (HN) for 42 (53%) and non-head and neck (NHN) for 38 (47%). Primary tumor risk factors were similar between cohorts. Fewer patients with HN tumors had wide local excision (WLE; HN-81% vs. NHN-100% p < 0.01). Of those undergoing WLE, patients with HN tumors received higher dose adjuvant RT (>50 Gy: HN-70% vs. NHN-8%; p < 0.01). Patients with HN tumors were less likely to undergo sentinel lymph node biopsy (HN-62%vs. NHN-100%; p < 0.01) and more likely to have elective nodal RT (HN-48% vs. NHN-0%). Despite varying management strategies, there was no significant difference in local recurrence-free survival (3-yr LRFS HN-94% vs. NHN-94%; p = 0.97), nodal recurrence-free survival (3-yr NRFS HN-89% vs. NHN-85%; p = 0.71) or overall recurrence-free survival (3-yr RFS 73% HN vs. 80% NHN; p = 0.44).

CONCLUSIONS

Among patients with primary MCC who had RT as a component of their initial treatment strategy, anatomically-driven heterogeneous treatment approaches were associated with equally excellent locoregional disease control.

Gut Microbiome in Patients With Early-Stage and Late-Stage Melanoma

Importance

The gut microbiome modulates the immune system and responses to immunotherapy in patients with late-stage melanoma. It is unknown whether fecal microbiota profiles differ between healthy individuals and patients with melanoma or if microbiota profiles differ among patients with different stages of melanoma. Defining gut microbiota profiles in individuals without melanoma and those with early-stage and late-stage melanoma may reveal features associated with disease progression.

Objective

To characterize and compare gut microbiota profiles between healthy volunteers and patients with melanoma and between patients with early-stage and late-stage melanoma.

Design, Setting, and Participants

This single-site case-control study took place at an academic comprehensive cancer center. Fecal samples were collected from systemic treatment-naive patients with stage I to IV melanoma from June 1, 2015, to January 31, 2019, and from healthy volunteers from June 1, 2021, to January 31, 2022. Patients were followed up for disease recurrence until November 30, 2021.

Main Outcomes and Measures

Fecal microbiota was profiled by 16S ribosomal RNA sequencing. Clinical and pathologic characteristics, treatment, and disease recurrence were extracted from electronic medical records. Fecal microbiome diversity, taxonomic profiles and inferred functional profiles were compared between groups.

Results

A total of 228 participants were enrolled (126 men [55.3%]; median age, 59 [range, 21-90] years), including 49 volunteers without melanoma, 38 patients with early-stage melanoma (29 with stage I or melanoma in situ and 9 with stage II), and 141 with late-stage melanoma (66 with stage III and 75 with stage IV). Community differences were observed between patients with melanoma and volunteers. Patients with melanoma had a higher relative abundance of Fusobacterium compared with controls on univariate analysis (0.19% vs 0.003%; P < .001), but this association was attenuated when adjusted for covariates (log2 fold change of 5.18 vs controls; P = .09). Microbiomes were distinct between patients with early-stage and late-stage melanoma. Early-stage melanoma had a higher alpha diversity (Inverse Simpson Index 14.6 [IQR, 9.8-23.0] vs 10.8 [IQR, 7.2-16.8]; P = .003), and a higher abundance of the genus Roseburia on univariate analysis (2.4% vs 1.2%; P < .001) though statistical significance was lost with covariate adjustment (log2 fold change of 0.86 vs controls; P = .13). Multiple functional pathways were differentially enriched between groups. No associations were observed between the microbial taxa and disease recurrence in patients with stage III melanoma treated with adjuvant immunotherapy.

Conclusions and Relevance

The findings of this case-control study suggest that fecal microbiota profiles were significantly different among patients with melanoma and controls and between patients with early-stage and late-stage melanoma. Prospective investigations of the gut microbiome and changes that occur with disease progression may identify future microbial targets for intervention.

Diverse clonal fates emerge upon drug treatment of homogeneous cancer cells

Even among genetically identical cancer cells, resistance to therapy frequently emerges from a small subset of those cells1-7. Molecular differences in rare individual cells in the initial population enable certain cells to become resistant to therapy7-9; however, comparatively little is known about the variability in the resistance outcomes. Here we develop and apply FateMap, a framework that combines DNA barcoding with single-cell RNA sequencing, to reveal the fates of hundreds of thousands of clones exposed to anti-cancer therapies. We show that resistant clones emerging from single-cell-derived cancer cells adopt molecularly, morphologically and functionally distinct resistant types. These resistant types are largely predetermined by molecular differences between cells before drug addition and not by extrinsic factors. Changes in the dose and type of drug can switch the resistant type of an initial cell, resulting in the generation and elimination of certain resistant types. Samples from patients show evidence for the existence of these resistant types in a clinical context. We observed diversity in resistant types across several single-cell-derived cancer cell lines and cell types treated with a variety of drugs. The diversity of resistant types as a result of the variability in intrinsic cell states may be a generic feature of responses to external cues.

Comparative analysis of opioid use between robotic and open pancreatoduodenectomy

BACKGROUND/PURPOSE

Risk-stratified pancreatectomy clinical pathways using regional anesthesia and multimodality analgesia have decreased overall opioid use, but the additional benefits of robotic surgery in opioid reduction for pancreatoduodenectomy (PD) are unknown. We compared the inpatient opioid use between robotic PD and open PD.

METHODS

Patients undergoing open PD within a protocol evaluating preincisional regional anesthetic block bundles were compared to consecutively-treated patients undergoing robotic PD identified from a prospectively maintained single-institutional database. Clinical characteristics, operative outcomes, pain scores and inpatient oral morphine equivalent (OME) use were compared between patients treated with robotic or open PD. Patients with a history of continuous-release opioid dependence were excluded.

RESULTS

Of 114 total patients, 25 underwent robotic PD and 89 underwent open PD. Intraoperative opioid use was not different (P = .87), nor were cumulative pain scores. Robotic PD patients used significantly fewer OMEs per day on postoperative days 1-4 (P = .039), used fewer total OMEs during hospitalization (robotic: median = 79, IQR 42.5-141; open: median = 126, IQR 61.3-203.8; P = .0036) and were discharged with fewer OMEs (robotic: median = 0, IQR 0-43.8; open: median = 25, IQR 0-75; P = .009) despite a shorter length of stay (robotic: median = 4, open: median = 5, P = .002).

CONCLUSIONS

Robotic PD patients required fewer inpatient OMEs than open PD while maintaining similar pain scores. A higher percentage of robotic PD patients tapered off of opioids prior to discharge than open surgery patients treated with a standardized opioid reduction protocol despite a shorter length of stay. These results provide a rationale for choosing robotic PD when feasible to minimize opioid use.

Clinical Impact of External Beam Radiotherapy for Surgically Resected Primary Retroperitoneal Liposarcoma

INTRODUCTION

EORTC-62092 (STRASS) was a phase 3, randomized study that compared surgery alone versus surgery plus neoadjuvant radiotherapy (RT) for retroperitoneal sarcomas. RT was not associated with improved abdominal recurrence-free survival, the primary outcome measure, although on subanalysis, there may have been benefit for well-differentiated (WD) liposarcoma. This study investigated the real-world use and outcomes of RT (neoadjuvant and adjuvant) for the management of retroperitoneal liposarcoma.

METHODS

We queried the National Cancer Database (NCDB) (2004-2017) for patients with nonmetastatic, primary retroperitoneal liposarcoma treated with resection with or without RT (n = 3911). Patients were stratified by treatment type and histology [WD (n = 2252), dedifferentiated (DD) (n = 1659)]. Propensity score (PS) matching was used before comparison of treatment groups. Overall survival (OS) was the primary outcome measure.

RESULTS

Median follow-up time was 4.1 years, and median OS was 10.7 years. There was no association between RT and OS for either WDLPS or DDLPS cohorts. We performed a subgroup analysis of neoadjuvant RT only, similar to STRASS. For WDLPS after PS matching (n = 208), neoadjuvant RT was not associated with OS (hazard ratio [HR] 1.01, p = 0.0523) but was associated with longer postoperative hospital stay (p = 0.012). For DDLPS after PS matching (n = 290), neoadjuvant RT was not associated with OS (HR 1.02, p = 0.889). For both WD-LPS and DD-LPS, utilization of neoadjuvant RT was associated with treatment at high-volume (≥ 10 cases/year) and academic/network facilities.

CONCLUSIONS

For primary retroperitoneal liposarcoma treated with surgical resection, radiotherapy was not associated with an overall survival benefit in this propensity-matched, adjusted analysis of the NCDB.

Practice Pattern Variability in the Management of Regional Lymph Node Metastasis in Extremity and Trunk Soft Tissue Sarcoma: A Survey of the Society of Surgical Oncology and Musculoskeletal Tumor Society Membership

BACKGROUND

Regional lymph node metastasis in extremity and trunk soft tissue sarcoma (ETSTS) is rare with no standardized management. We sought to determine management patterns for regional lymph node metastasis in ETSTS.

METHODS

A survey regarding the management of ETSTS lymph node metastasis was distributed to the membership of the Musculoskeletal Tumor Society (MSTS) and the Society of Surgical Oncology (SSO) in January 2022. The survey queried the type of training (surgical oncology, orthopedic oncology), details of their practice setting, and management decisions of hypothetical ETSTS scenarios that involved potential or confirmed lymph node metastasis.

RESULTS

The survey was distributed to 349 MSTS members (open rate of 63%, completion rate 21%) and 3026 SSO members (open rate of 55%, completion rate 4.7%) and was completed by 214 respondents, of whom 73 (34.1%) and 141 (65.9%) were orthopedic oncology and surgical oncology fellowship-trained, respectively. The majority of respondents practiced in an academic setting (n = 171, 79.9%) and treat >10 extremity sarcoma cases annually (n = 138, 62.2%). In scenarios with confirmed nodal disease for clear cell and epithelioid sarcoma, surgical oncologists were inclined to perform lymphadenectomy, while orthopedic oncologists were inclined to offer targeted lymph node excision with adjuvant radiation (p < 0.001). There was heterogeneity of responses regarding the management of nodal disease regardless of training background.

CONCLUSION

Self-reported management of nodal disease in ETSTS was variable among respondent groups with differences and similarities based on training background. These data highlight the variability of practice for nodal disease management and the need for consensus-based guidelines.

Modulation of the Gut Microbiome to Enhance Immunotherapy Response in Metastatic Melanoma Patients: A Clinical Review

For patients with metastatic melanoma, immunotherapy agents represent a promising treatment option, and researchers are actively seeking to identify factors that may predict a favorable response in patients. Recent studies have elucidated possible associations between the gut microbiome and the effects of immunotherapy, where variations in the gut microbiome may influence treatment response and frequency of adverse effects. In this clinical review, we describe the current literature related to the gut microbiome in the setting of immunotherapy, and we provide an overview of interventions under investigation that may modulate the gut microbiome. These interventions include fecal microbiota transplantation, probiotics, and dietary modifications.

The immune landscape of undifferentiated pleomorphic sarcoma

Introduction

Undifferentiated pleomorphic sarcoma (UPS) can be associated with a relatively dense immune infiltration. Immune checkpoint inhibitors (anti-PD1, anti-PDL1, and anti-CTLA4) are effective in 20% of UPS patients. We characterize the immune microenvironment of UPS and its association with oncologic outcomes.

Material and methods

Surgically resected UPS samples were stained by immunohistochemistry (IHC) for the following: tumor-associated immune cells (CD3, CD8, CD163, CD20), immune checkpoints (stimulatory: OX40, ICOS; inhibitory: PD-L1, LAG3, IDO1, PD1), and the adenosine pathway (CD73, CD39). Sections were reviewed for the presence of lymphoid aggregates (LA). Clinical data were retrospectively obtained for all samples. The Wilcoxon rank-sum and Kruskal-Wallis tests were used to compare distributions. Correlations between biomarkers were measured by Spearman correlation. Univariate and multivariate Cox models were used to identify biomarkers associated with overall survival (OS) and disease-free survival (DFS). Unsupervised clustering was performed, and Kaplan-Meier curves and log-rank tests used for comparison of OS and DFS between immune clusters.

Results

Samples analyzed (n=105) included 46 primary tumors, 34 local recurrences, and 25 metastases. LA were found in 23% (n=10/43), 17% (n=4/24), and 30% (n=7/23) of primary, recurrent, and metastatic samples, respectively. In primary UPS, CD73 expression was significantly higher after preoperative radiation therapy (p=0.009). CD39 expression was significantly correlated with PD1 expression (primary: p=0.002, recurrent: p=0.004, metastatic: p=0.001), PD-L1 expression (primary: p=0.009), and CD3+ cell densities (primary: p=0.016, recurrent: p=0.043, metastatic: p=0.028). In recurrent tumors, there was a strong correlation between CD39 and CD73 (p=0.015), and both were also correlated with CD163+ cell densities (CD39 p=0.013; CD73 p<0.001). In multivariate analyses, higher densities of CD3+ and CD8+ cells (Cox Hazard Ratio [HR]=0.33; p=0.010) were independently associated with OS (CD3+, HR=0.19, p<0.001; CD8+, HR= 0.33, p=0.010) and DFS (CD3+, HR=0.34, p=0.018; CD8+, HR=0.34, p= 0.014). Unsupervised clustering of IHC values revealed three immunologically distinct clusters: immune high, intermediate, and low. In primary tumors, these clusters were significantly associated with OS (log-rank p<0.0001) and DFS (p<0.001).

Conclusion

We identified three immunologically distinct clusters of UPS Associated with OS and DFS. Our data support further investigations of combination anti-PD-1/PD-L1 and adenosine pathway inhibitors in UPS.

Sentinel Lymph Node Biopsy and Formal Lymphadenectomy for Soft Tissue Sarcoma: A Single Center Experience of 86 Consecutive Cases

BACKGROUND

Lymph node metastases (LNMs) are rare in patients with soft tissue sarcoma (STS), and there is limited evidence to guide clinical management. We describe our experience with sentinel lymph node biopsy (SLNB) and lymphadenectomy in STS patients.

METHODS

A single-center, retrospective review was performed for patients with STS treated with SLNB and/or lymphadenectomy from 1994 to 2018. Clinicopathologic characteristics, multimodality treatment, regional/distant recurrence-free survival (RFS), and overall survival (OS) were examined.

RESULTS

Eighty-six patients underwent SLNB (n = 34) and/or lymphadenectomy (n = 60) for STS. The most frequent histologic subtypes were epithelioid, clear cell, and undifferentiated pleomorphic sarcoma. Eight of 34 (23.5%) patients had a positive SLNB with 5-year OS of 71.4% compared with 71.9% for those with a negative SLNB. Eight of the 26 SLN-negative patients (30.8%) eventually developed nodal recurrence (n = 2) and/or (n = 6) distant metastasis with an estimated 5-year OS of 50%. Of patients undergoing lymphadenectomy, estimated 5-year OS was 44.6% and median RFS was 12 months. Eight (13.3%) had distant disease at time of lymphadenectomy, 20 (33.3%) developed distant recurrence after lymphadenectomy, and 6 (10%) developed regional-only recurrence. Patients with regional-only recurrence after lymphadenectomy had an estimated 5-year OS of 66.7% compared with 29.1% for those who recurred distantly.

CONCLUSIONS

Patients with positive SLNB had similar survival to those with negative SLNB. Lymphadenectomy for isolated nodal disease is associated with poor RFS but reasonable 5-year OS when recurrence is regional-only. In STS, regional disease appears clinically distinct from distant metastatic disease and has better outcomes.

Abstract PR002: Antigen presentation and processing pathway is associated with early relapse after neoadjuvant immune checkpoint blockade (ICB) in dedifferentiated liposarcomas (DDLPS)

Background: We evaluated the activity of neoadjuvant ICB in localized resectable DDLPS (n=17) and undifferentiated pleomorphic sarcomas (UPS; n=10). DDLPS and UPS patients were randomized to neoadjuvant nivolumab or ipilimumab+nivolumab, with UPS patients receiving concurrent radiotherapy. We assessed genomic markers of early relapse (progression before surgery or relapse within 52 weeks following surgery) using longitudinally acquired tumor samples. Methods: RNA sequencing (RNAseq) and whole genome sequencing (WGS) were performed on longitudinally acquired samples (baseline biopsies and surgical specimens). Differential gene expression between any two groups of patients (i.e., non-early relapse [non-relapsers] vs early relapse [relapsers]) were selected (fold change&gt;1.5 and p value&lt;0.05). Gene set enrichment analyses (GSEA) of KEGG pathways were performed and a network-based approach used to identify genes/pathways associated with MHC-I. Results: At a median follow-up of 23 months, 12 patients (9 DDLPS, 3 UPS) relapsed, including 7 early relapses (relapsers: 5 DDLPS, 2 UPS). The median relapse-free survival was 22 months in DDLPS patients (6 months in relapsers; not reached [NR] in non-relapsers) and NR in UPS patients. At baseline, the most differentially upregulated pathways in non-relapsers compared to relapsers were “graft versus host disease” (GSEA Normalized Enrichment Score[NES]=2.25; False Discovery Rate[FDR] q= 0.009), “natural killer cell mediated cytotoxicity” (NES=2.17; FDR q=0.009), “antigen processing and presentation” (NES=2.16; FDR q=0.009), “allograft rejection” (NES=1.99; FDR q=0.019) and “B-cell receptor signaling pathway” (NES=1.87; FDR q=0.018). In DDLPS patients, the antigen presentation and processing pathway was the most upregulated pathway in non-relapsers compared to relapsers (NES=2.01; FDR q=0.025) while it was not significantly upregulated in UPS (NES=1.15; FDR q=0.62). When looking at pathways longitudinally, the antigen presentation and processing pathway was significantly upregulated at surgery compared to baseline in DDLPS. As antigen presentation and processing was significantly upregulated in DDLPS patients and associated with relapse, we looked for expressed neoantigens that may be processed and presented. Using WGS, we detected 5712 rearrangements at baseline in DDLPS, of which 230 were found in more than one tumor specimen. We also sought to identify genes associated with MHC-I. We selected genes upregulated during ICB comparing baseline to surgical specimens in DDLPS relapsers and looked at the top 10% of genes associated with MHC-I in order to identify potential therapeutic targets for combination. We identified 41 genes upregulated during ICB and associated with MHC-I in relapsers, for which up to 275 inhibitory compounds were found in drug databases. Conclusion: Antigen presentation and processing is a major driver of response to immunotherapy. Future efforts should focus on identifying which antigens are presented to find synergizing compounds in order to increase the clinical benefit of ICB.

Citation Format: Elise F. Nassif, Chia-Chin Wu, Kadir Akdemir, Russell G. Witt, Raymond Traweek, Brandon Cope, Prapassorn Thirasastr, Taylor Tate, Grace Mathew, Shadarra Crosby, Randy Chu, Mohammad Mohammad, Kenna Shaw, Ingram Davis, Khalida Wani, Alexander J. Lazar, Wei-Lien Wang, Sheila Duncan, Ashleigh B. Guadagnolo, Andrew J. Bishop, Valerae Lewis, Justin E. Bird, Keila E. Torres, Kelly K. Hunt, Barry W. Feig, Christopher P. Scally, Ravin Ratan, Shreyaskumar Patel, Robert S. Benjamin, Robert Satcher, Kevin McBride, Wolf H. Fridman, Ignacio Wistuba, Andrew Futreal, Jennifer A. Wargo, Neeta Somaiah, Christina L. Roland, Emily Z. Keung. Antigen presentation and processing pathway is associated with early relapse after neoadjuvant immune checkpoint blockade (ICB) in dedifferentiated liposarcomas (DDLPS) [abstract]. In: Proceedings of the AACR Special Conference: Sarcomas; 2022 May 9-12; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2022;28(18_Suppl):Abstract nr PR002.

Real-world use of palbociclib monotherapy in retroperitoneal liposarcomas at a large volume sarcoma center

Palbociclib has been evaluated in early phase trials for well-differentiated liposarcoma (WDLPS) and dedifferentiated liposarcoma (DDLPS) patients, with reported median progression-free survival (PFS) of 18 weeks. Here, we report on real-world use and surgical outcomes associated with palbociclib treatment. We retrospectively reviewed 61 consecutive patients with retroperitoneal WDLPS (n = 14) or DDLPS (n = 47) treated with palbociclib monotherapy between 1 March 2016 and 28 February 2021 at The University of Texas MD Anderson Cancer Center. At palbociclib initiation, median age was 64 (interquartile range [IQR] 56-72). In WDLPS and DDLPS cohorts, the median number of prior systemic treatments was 0 (IQR 0-0) and 2 (IQR 0-4), respectively. Median number of prior surgeries was 2 (WDLPS IQR 1-2.75) and 2 (DDLPS IQR 1-3). Median PFS was 9.2 (WDLPS IQR 3.9-21.9) and 2.6 months (DDLPS IQR 2.0-6.1), with median time on treatment of 7.4 months (WDLPS IQR 3.5-14.2) and 2.7 months (DDLPS IQR 2.0-5.7). Twelve patients ultimately underwent surgical resection. Resections were macroscopically complete (R0/R1) in half (n = 6/12), among whom only one patient experienced relapse after resection (median follow-up 7.5 months). All patients who underwent macroscopically incomplete resections progressed after surgery with median time to progression of 3.3 months (IQR 2.3-4.4). Surgery after palbociclib treatment was not associated with improved overall survival. Efficacy of palbociclib monotherapy for patients with advanced WDLPS and DDLPS is disappointing. While palbociclib may have been used to delay surgery, there was no clear benefit from treatment and few patients achieved prolonged tumor control.

Androgen receptor blockade promotes response to BRAF/MEK-targeted therapy

9523

Background: Treatment with BRAF+/-MEK inhibition (BRAF+/-MEKi) has revolutionized treatment in melanoma and other cancers, but resistance is common and innovative treatment strategies are needed. Sexual dimorphism in response to BRAF+/-MEKi have been noted, but mechanisms behind this are poorly understood and hormonal modulation has not been well-studied in this setting. Methods: We examined outcomes by sex in five clinical cohorts of patients (pts) (total n = 792, 362 female, 430 male) with BRAF-mutated melanoma who were treated with BRAF/MEKi in either the neoadjuvant or metastatic setting. Rates of major pathologic response (MPR), clinical benefit (CB), progression free survival (PFS) relapse-free survival (RFS) and overall survival (OS) were assessed. Translational research studies were performed on available pre- and on-treatment tumor samples (n = 27 pts) including RNA sequencing and profiling androgen receptor (AR) expression. Parallel studies were performed in preclinical models to assess the effect of sex and AR modulation on response to BRAF+/-MEKi. Results: In this study, improved rates of MPR, CB, PFS and OS were observed in female vs male pts. Specifically, female patients treated with neoadjuvant BRAF+MEKi showed significantly higher rates of MPR (66% v. 14%, p = 0.001), and improved RFS (64% versus 32% at 2 years, p = 0.021) vs male pts in the neoadjuvant setting (n = 51). These findings were not observed in a 2nd smaller trial of pts (n = 35), but were validated in a cohort of pts with unresectable metastatic melanoma treated with BRAF+MEKi (n = 69), with significantly higher rates of CB (80% v. 68%, p = 0.022) and PFS (12 v. 7 months, p = 0.003) in female vs male pts. Data from several published trials was analyzed (COMBI-D and METRIC trials), demonstrating improved PFS/OS at 2 years in female vs male pts treated with combined BRAF/MEKi (n = 211; p = 0.03 and, p = 0.04) and in female vs male pts treated with MEKi monotherapy (n = 206; p = 0.04 and p = 0.002), but not in female vs male pts treated with BRAFi monotherapy (n = 211; p = 0.21 and 0.095). Significantly higher expression AR expression was observed in available on- vs pre-treatment samples from male pts (p = 0.01), suggesting that treatment with BRAF/MEKi may induce AR expression in tumors. Findings were recapitulated in several preclinical models, and treatment with pharmacologic inhibitors of AR signaling (enzalutamide) in combination with BRAF/MEKi was associated with significantly enhanced anti-tumor activity in both male and female mice (p = 0.003 and p < 0.0001). Conversely, systemic treatment with testosterone was associated with significantly impaired tumor control in male and female mice (p = 0.021 and < 0.001). Conclusions: These data suggest that AR blockade may promote BRAF/MEKi response in melanoma, warranting further investigation in clinical trials. The impact of AR signaling, and modulation should be studied in MAPK-targeted therapy across other cancer types.

Androgen receptor blockade promotes response to BRAF/MEK-targeted therapy

Treatment with therapy targeting BRAF and MEK (BRAF/MEK) has revolutionized care in melanoma and other cancers; however, therapeutic resistance is common and innovative treatment strategies are needed^1,2. Here we studied a group of patients with melanoma who were treated with neoadjuvant BRAF/MEK-targeted therapy ( NCT02231775 , n = 51) and observed significantly higher rates of major pathological response (MPR; ≤10% viable tumour at resection) and improved recurrence-free survival (RFS) in female versus male patients (MPR, 66% versus 14%, P = 0.001; RFS, 64% versus 32% at 2 years, P = 0.021). The findings were validated in several additional cohorts^2-4 of patients with unresectable metastatic melanoma who were treated with BRAF- and/or MEK-targeted therapy (n = 664 patients in total), demonstrating improved progression-free survival and overall survival in female versus male patients in several of these studies. Studies in preclinical models demonstrated significantly impaired anti-tumour activity in male versus female mice after BRAF/MEK-targeted therapy (P = 0.006), with significantly higher expression of the androgen receptor in tumours of male and female BRAF/MEK-treated mice versus the control (P = 0.0006 and P = 0.0025). Pharmacological inhibition of androgen receptor signalling improved responses to BRAF/MEK-targeted therapy in male and female mice (P = 0.018 and P = 0.003), whereas induction of androgen receptor signalling (through testosterone administration) was associated with a significantly impaired response to BRAF/MEK-targeted therapy in male and female patients (P = 0.021 and P < 0.0001). Together, these results have important implications for therapy.

A single-center experience of 98 patients (pts) with regionally metastatic Merkel cell carcinoma (MCC) of known (MCCKP) and unknown (MCCUP) primary at presentation

9576

Background: MCC is a rare skin cancer historically associated with poor survival rates and which is increasing in incidence. A small number of retrospective series suggest that MCCUP may be associated with better prognosis than MCCKP while others report worse outcomes. Recent advances in immunotherapy have changed the multimodal treatment landscape and outcomes of advanced MCC pts. We describe our experience with the management and outcomes of pts presenting with regional MCC metastasis of known and unknown primary origin. Methods: A retrospective review of pts with clinical regional disease at MCC diagnosis treated at our institution from 3/2003-3/2021 was performed. Clinicopathologic variables and outcomes were assessed. Overall survival (OS), recurrence-free survival (RFS) and progression-free survival (PFS) were estimated by the Kaplan Meier method. Results: Of 98 pts with regional disease on exam at presentation, 56 (57%) had MCCUP and 42 (43%) had MCCKP. Median follow-up from diagnosis to last follow-up or death was 33 months. Pts were generally older (MCCUP vs MCCKP: 68.7 vs 73.1 years), male (MCCUP vs MCCKP: 82% vs 74%) and Caucasian (MCCUP vs MCCKP: 84% vs 83%). Over half the pts had a history of another malignancy (MCCUP vs MCCKP: 52% vs 60%) with 9% and 14% being immunocompromised at diagnosis, respectively. After completion of staging workup, MCCUP pts had earlier stage disease at presentation compared with MCCKP pts (stage IIIA: 80% vs 55%, IIIB: 5% vs 31%, IV: 15% vs 14%, respectively). The cervical nodal basin was most commonly involved in MCCUP pts while regional disease was more varied in MCCKP pts (MCCUP vs MCCKP: cervical 54% vs 28%, axillary 15% vs 33%, inguinal 33% vs 3%, inguinal and pelvic 0% vs 11%, in transit 0% vs 14%). Formal lymphadenectomy (LND) was performed in 27 (48%) and 18 (43%) of MCCUP and MCCKP pts, respectively. Of these pts, 33% and 50% received neoadjuvant systemic therapy, most commonly immunotherapy; 70% and 55% received adjuvant radiotherapy. MCCUP pts had better outcomes compared to MCCKP pts (Table), with longer RFS in pts who underwent LND (not reached [NR] vs 13.1 months) as well as longer PFS in pts who did not undergo LND (17 vs 9 months) with longer OS in both subgroups (LND: NR vs 102.7 months; no LND: 74.4 vs 48.7 months). Conclusions: MCCUP patients with regional disease on exam at presentation have improved survival compared to MCCKP. Current stage III survival estimates may underestimate survival in patients with resectable disease. [Table: see text]

Identifying gut microbial signatures associated with B cells and tertiary lymphoid structures (TLS) in the tumor microenvironment (TME) in response to immune checkpoint blockade (ICB)

2511

Background: While ICB has significantly improved clinical outcomes across several cancer types, only 15-20% of patients develop a durable response. Thus, novel and targetable biomarkers are needed. There is increased appreciation of the role of the gut microbiome, and TLS and B-cells in the TME in response to ICB. Here, we investigate the association between these two determinants of response in patient specimens from three randomized phase 2 neoadjuvant ICB trials of nivolumab +/- ipilimumab (melanoma (MEL; NCT02519322; n=23), non-small-cell lung cancer (NSCLC; NCT03158129; n=31), sarcoma (SARC; NCT02301039; n=17). Methods: Patients were categorized as responders (R) or non-responders (NR) based on major pathologic response, as defined in each histotype (MEL and NSCLC viable tumor ≤10%; SARC hyalinization>30%). Baseline fecal samples were profiled via 16S rRNA gene sequencing from all three cohorts to assess the composition of patient gut microbiomes. Transcriptional profiles of biopsies collected pre-ICB for MEL and SARC, and post-ICB for MEL, SARC, and NSCLC were used to assess TLS (CXCL13, CCL18, CCL19, CCL21) and B-cell (PAX5, CD79B, CR2, MS4A1) signatures in the TME, by calculated mean values of normalized gene expressions. Comparison between samples were carried out using the Wilcoxon signed-rank test. Results: There were 21 R overall (NSCLC n=9; MEL n=9; SARC n=3). Despite significant differences in alpha and beta diversity across cohorts, relative abundance of Ruminococcus was significantly higher in R (p=0.003; NSCLC p<0.001; MEL p=0.049; SARC p=0.7). B-cell signature was significantly higher post-ICB in R (R vs NR, post, TLS p=0.13; B-cell p=0.003), with consistent trends in each cohort. Longitudinal evaluation of transcriptional profiles showed that expression of TLS and B-cell signatures increased with treatment in R (pre vs post, MEL and SARC; TLS p=0.0098; B-cell p<0.001) but not NR (pre vs post; TLS p= 0.87; B-cell p= 0.15), with consistent trends in sarcoma and melanoma subgroups. Combined correlative analysis with matched specimen showed that patients with higher pre-ICB relative abundance of Ruminococcus (above median) had significant increase in B-cell signatures (pre vs post, MEL and SARC; TLS p=0.052; B-cell p=0.002) which was not seen in patients with low abundance (below median) of Ruminococcus (pre vs post, MEL and SARC; TLS p=0.56; B-cell p=0.69). Conclusions: Unifying signatures in the gut microbiome are associated with response to ICB and increased B-cell infiltration and TLS formation in the TME. We expect these findings to energize mechanistic studies and new microbiome-based interventional approaches to improve clinical outcomes with ICB. Clinical trial information: NCT02519322, NCT03158129, NCT02301039.

Evaluating the impact of perioperative antibiotic prophylaxis on the microbiome in patients with cutaneous malignancy

TPS9602

Background: Preoperative antibiotic prophylaxis is commonly used to reduce surgical site infections (SSIs). However, the rate of SSIs following surgical procedures classified as clean is only 2-3%. Overuse of antibiotics is associated with several potential adverse effects, including dysregulation of the gut microbiome. Disruption of the composition and function of the native gut microbiota, referred to as dysbiosis, has been implicated in a number of inflammatory and autoimmune disorders, as well as gastrointestinal (GI) and non-GI cancers. Recent studies have demonstrated that antibiotics have a profound and persistent effect on the gut microbiota, as evidenced by diminished overall abundance and diversity, as well as alteration of community composition that includes a decreased relative abundance of bacteria in the Ruminococcaceae family. In melanoma, diversity of gut microbiota and relative abundance of Ruminococaceae have been linked to improved survival and enhanced response following immune checkpoint blockade. In this study, we seek to determine the impact of preoperative prophylactic antibiotic use on the gut microbiome in patients following surgery for stage I or II melanoma. Methods: In this non-comparative randomized pilot trial, the impact of prophylactic antibiotic use at the time of surgical intervention on gut microbiome diversity and composition will be studied. Patients diagnosed with clinical stage I or II melanoma undergoing wide excision with or without lymphatic mapping and sentinel lymph node biopsy are randomized 1:1 to either receive preoperative cefazolin or no preoperative antibiotics. Stool samples and peripheral blood are collected before surgery, the day of surgery (optional), on post-operative day 3 (optional), and 2 weeks and 3 months following surgery. The primary endpoint for the study is change in microbiome alpha diversity at 2 weeks following surgery. Secondary endpoints are change in relative abundance of microbes at 2 weeks and 3 months after surgery and SSI rates according to whether or not prophylactic antibiotics were administered at time of surgery. Exclusion criteria include recent antibiotic use (within 3 months), allergy to beta-lactam or cephalosporin antibiotics, increased risk of infection due to medical comorbidity or use of immunosuppressive medication. Enrollment began in October 2021. As of January 2022, 22 of 30 patients have been accrued to ensure complete sample collection for 20 patients. Study findings may inform a larger trial evaluating interventions to mitigate antibiotic impact. Clinical trial information: NCT04875728.

Analysis of Opioid Use in Patients Undergoing Open Versus Robotic Gastrectomy

BACKGROUND

Minimally invasive, robotic gastrectomy is associated with better short-term outcomes and quicker functional recovery. However, the degree to which the robotic approach influences postoperative pain and opioid use after gastrectomy is unknown. Our primary aim was to determine whether the robotic approach to gastrectomy reduces postoperative opioid use compared with the open approach.

METHODS

Patients who underwent gastrectomy (November 2018 to September 2021) were identified retrospectively. Clinical characteristics, short-term surgical outcomes, oral morphine equivalent (OME) use, and pain scores were collected. Both groups were managed through an enhanced recovery program in the perioperative period.

RESULTS

Of 81 patients, 50 underwent open and 31 underwent robotic gastrectomy. Compared with open gastrectomy patients, robotic gastrectomy patients had longer surgery time (360 vs. 288 min), less blood loss (50 vs. 138 mL), and shorter hospital stay (4 vs. 6 days) (all medians, P < 0.001). Robotic gastrectomy patients used lower OMEs on postoperative days 0-4 (all P < 0.05) and in total for days 0-4 (total mean dose 65.0 vs. 169.5 mg; P < 0.001) than did open gastrectomy patients. The robotic gastrectomy patients were prescribed a lower mean OME dose than the open gastrectomy patients (19.0 vs. 29.0 mg, respectively; P = 0.001). Multivariable analysis showed that robotic approach was associated with lower opioid use (odds ratio 3.70; 95% CI 1.01-14.3; P = 0.049).

CONCLUSIONS

Compared with open gastrectomy, robotic gastrectomy reduces opioid use in the early postoperative period and is associated with fewer OME discharge prescriptions and shorter hospital stay.

Neoadjuvant therapy for melanoma: rationale for neoadjuvant therapy and pivotal clinical trials

The treatment of malignant melanoma has drastically changed over the past decade with the advent of immune checkpoint blockade, targeted therapy with BRAF/MEK inhibition, and other novel therapies such as oncolytic virus intralesional therapy. Despite improvements in patient response rates and survival with these new treatments, there exists a large portion of patients with surgically resectable disease that are high risk for relapse. Patients with high-risk resectable melanoma account for up to 20% of newly diagnosed cases. For this high-risk group of patients, neoadjuvant therapy has many purposed advantages over adjuvant therapy, including a more robust immune response due to abundant tumor antigens at treatment initiation, the ability to assess pathologic response to therapy, tumor downstaging leading to increased disease resectability, and a potential decreased need for extensive lymphadenectomies. These findings have been backed by preclinical models and multiple neoadjuvant trials are underway. In this review, we will discuss the trials that have set the foundation for the current treatment standards and discuss the role and rationale for neoadjuvant therapy for high-risk malignant melanomas.

Utilization and evolving prescribing practice of opioid and non-opioid analgesics in patients undergoing lymphadenectomy for cutaneous malignancy

BACKGROUND AND OBJECTIVES

Opioids are commonly prescribed following surgery and can lead to persistent opioid use. We assessed changes in prescribing practices following an opioid education initiative for patients undergoing lymphadenectomy for cutaneous malignancy.

METHODS

A single-institution retrospective study of all eligible patients (3/2016-3/2020) was performed.

RESULTS

Indications for lymphadenectomy in 328 patients were metastatic melanoma (84%), squamous cell carcinoma (10%), and Merkel cell carcinoma (5%). At discharge, non-opioid analgesics were increasingly utilized over the 4-year study period, with dramatic increases after education initiatives (32%, 42%, 59%, and 79% of pts, respectively each year; p < 0.001). Median oral morphine equivalents (OMEs) prescribed also decreased dramatically starting in year 3 (250, 238, 150, and 100 mg, respectively; p < 0.001). Patients discharged with 200 mg OMEs were less likely to also be discharged with non-opioid analgesics (40% vs. 64%. respectively, p < 0.001).

CONCLUSIONS

Analgesic prescribing practices following lymphadenectomy for cutaneous malignancy improved significantly over a 4-year period, with use of non-opioids more than doubling and a 60% reduction in median OME. Opportunities exist to further increase non-opioid use and decrease opioid dissemination after lymphadenectomy for cutaneous malignancy.

Neoadjuvant therapy for melanoma: new and evolving concepts

Effective systemic therapies, including targeted BRAF/MEK inhibition and immune checkpoint blockade, have significantly changed the treatment landscape for malignant melanoma. Specifically, there have been promising clinical trial findings associated with the use of neoadjuvant therapy for clinically node-positive and oligometastatic disease, conditions that have historically been managed with up-front surgical resection when possible. This review focuses on the burgeoning field of neoadjuvant therapy for melanoma. We review the rationale for this treatment approach, summarize completed and ongoing neoadjuvant clinical trials, and contextualize these findings within the growing body of knowledge about targeted and immune checkpoint therapy. Finally, we discuss future directions for neoadjuvant trials in melanoma, with particular focus on biomarker development, treatment effect modification, novel therapeutic regimens, and evolving surgical indications for regional and oligometastatic disease.

Short-term treatment with multi-drug regimens combining BRAF/MEK-targeted therapy and immunotherapy results in durable responses in Braf-mutated melanoma

Targeted and immunotherapy regimens have revolutionized the treatment of advanced melanoma patients. Despite this, only a subset of patients respond durably. Recently, combination strategies of BRAF/MEK inhibitors with immune checkpoint inhibitor monotherapy (α-CTLA-4 or α-PD-1) have increased the rate of durable responses. Based on evidence from our group and others, these therapies appear synergistic, but at the cost of significant toxicity. We know from other treatment paradigms (e.g. hematologic malignancies) that combination strategies with multi-drug regimens (>4 drugs) are associated with more durable disease control. To better understand the mechanism of these improved outcomes, and to identify and prioritize new strategies for testing, we studied several multi-drug regimens combining BRAF/MEK targeted therapy and immunotherapy combinations in a Braf-mutant murine melanoma model (Braf^V600E/Pten^−/−). Short-term treatment with α-PD-1 and α-CTLA-4 monotherapies were relatively ineffective, while treatment with α-OX40 demonstrated some efficacy [17% of mice with no evidence of disease, (NED), at 60-days]. Outcomes were improved in the combined α-OX40/α-PD-1 group (42% NED). Short-term treatment with quadruplet therapy of immunotherapy doublets in combination with targeted therapy [dabrafenib and trametinib (DT)] was associated with excellent tumor control, with 100% of mice having NED after combined DT/α-CTLA-4/α-PD-1 or DT/α-OX40/α-PD-1. Notably, tumors from mice in these groups demonstrated a high proportion of effector memory T cells, and immunologic memory was maintained with tumor re-challenge. Together, these data provide important evidence regarding the potential utility of multi-drug therapy in treating advanced melanoma and suggest these models can be used to guide and prioritize combinatorial treatment strategies.

Identification of MicroRNA-mRNA Networks in Melanoma and Their Association with PD-1 Checkpoint Blockade Outcomes

Metastatic melanoma is a deadly malignancy with poor outcomes historically. Immuno-oncology (IO) agents, targeting immune checkpoint molecules such as cytotoxic T-lymphocyte associated protein-4 (CTLA-4) and programmed cell death-1 (PD-1), have revolutionized melanoma treatment and outcomes, achieving significant response rates and remarkable long-term survival. Despite these vast improvements, roughly half of melanoma patients do not achieve long-term clinical benefit from IO therapies and there is an urgent need to understand and mitigate mechanisms of resistance. MicroRNAs are key post-transcriptional regulators of gene expression that regulate many aspects of cancer biology, including immune evasion. We used network analysis to define two core microRNA-mRNA networks in melanoma tissues and cell lines corresponding to 'MITF-low' and 'Keratin' transcriptomic subsets of melanoma. We then evaluated expression of these core microRNAs in pre-PD-1-inhibitor-treated melanoma patients and observed that higher expression of miR-100-5p and miR-125b-5p were associated with significantly improved overall survival. These findings suggest that miR-100-5p and 125b-5p are potential markers of response to PD-1 inhibitors, and further evaluation of these microRNA-mRNA interactions may yield further insight into melanoma resistance to PD-1 inhibitors.

Tolerance induction and microglial engraftment after fetal therapy without conditioning in mice with Mucopolysaccharidosis type VII

Mucopolysaccharidosis type VII (MPS7) is a lysosomal storage disorder (LSD) resulting from mutations in the β-glucuronidase gene, leading to multiorgan dysfunction and fetal demise. While postnatal enzyme replacement therapy (ERT) and hematopoietic stem cell transplantation have resulted in some phenotypic improvements, prenatal treatment might take advantage of a unique developmental window to penetrate the blood-brain barrier or induce tolerance to the missing protein, addressing two important shortcomings of postnatal therapy for multiple LSDs. We performed in utero ERT (IUERT) at E14.5 in MPS7 mice and improved survival of affected mice to birth. IUERT penetrated brain microglia, whereas postnatal administration did not, and neurological testing (after IUERT plus postnatal administration) showed decreased microglial inflammation and improved grip strength in treated mice. IUERT prevented antienzyme antibody development even after multiple repeated postnatal challenges. To test a more durable treatment strategy, we performed in utero hematopoietic stem cell transplantation (IUHCT) using congenic CX3C chemokine receptor 1-green fluorescent protein (CX3CR1-GFP) mice as donors, such that donor-derived microglia are identified by GFP expression. In wild-type recipients, hematopoietic chimerism resulted in microglial engraftment throughout the brain without irradiation or conditioning; the transcriptomes of donor and host microglia were similar. IUHCT in MPS7 mice enabled cross-correction of liver Kupffer cells and improved phenotype in multiple tissues. Engrafted microglia were seen in chimeric mice, with decreased inflammation near donor microglia. These results suggest that fetal therapy with IUERT and/or IUHCT could overcome the shortcomings of current treatment strategies to improve phenotype in MPS7 and other LSDs.

O27: MICROGLIAL CORRECTION AFTER FETAL THERAPY WITHOUT CONDITIONING IN MICE WITH MUCOPOLYSACCHARIDOSIS TYPE VII

Introduction

Mucopolysaccharidosis type 7 (MPS7) is a lysosomal storage disorder typically fatal in utero. Postnatal enzyme replacement therapy (ERT) to replace missing glucuronidase (GUS) does not penetrate the blood-brain barrier (BBB). We investigated whether in utero ERT (IUERT) specifically targets brain microglia (natural GUS storehouses and key brain inflammation mediators) and whether in utero hematopoietic stem cell transplantation (IUHSCT) results in microglial engraftment as a strategy for permanent correction.

Methods

We performed IUERT by injecting GUS into MPS7 fetuses mid-gestation, and analyzed tissue homogenates (via colorimetric substrate) and brain microglia (via flow cytometry) for enzyme activity after 4-7 days. We performed IUHSCT by transplanting HSCs mid-gestation from CX3CR1-GFP donors. We examined blood, bone marrow, and brain for engraftment. We assessed brain inflammation by staining for CD68. We performed RNA sequencing to characterize engrafted microglia.

Results

IUERT resulted in detectable brain GUS activity. Flow cytometry showed that GUS activity after IUERT was near wild-type levels, and brains harvested in adulthood had decreased inflammation via CD68 immunohistochemistry. IUHSCT resulted in multilineage engraftment of hematopoietic cells in blood and bone. Confocal microscopy revealed multifocal engraftment of donor-derived microglia. RNA sequencing indicated that engrafted microglia were nearly identical to endogenous microglia. MPS7 chimeras had evidence of reduced brain inflammation near donor microglia.

Conclusion

Both IUERT and IUHSCT are complementary treatment modalities that can penetrate the BBB and ameliorate neurologic manifestations of diseases such as MPS7. These results lay the foundation for future studies using in utero molecular therapies for MPS7 as well as other storage disorders.

Detection of microbial cell-free DNA in maternal and umbilical cord plasma in patients with chorioamnionitis using next generation sequencing

Background

Chorioamnionitis has been linked to spontaneous preterm labor and complications such as neonatal sepsis. We hypothesized that microbial cell-free (cf) DNA would be detectable in maternal plasma in patients with chorioamnionitis and could be the basis for a non-invasive method to detect fetal exposure to microorganisms.

Objective

The purpose of this study was to determine whether next generation sequencing could detect microbial cfDNA in maternal plasma in patients with chorioamnionitis.

Study design

Maternal plasma (n = 94) and umbilical cord plasma (n = 120) were collected during delivery at gestational age 28–41 weeks. cfDNA was extracted and sequenced. Umbilical cord plasma samples with evidence of contamination were excluded. The prevalence of microorganisms previously implicated in choriomanionitis, neonatal sepsis and intra-amniotic infections, as described in the literature, were examined to determine if there was enrichment of these microorganisms in this cohort. Specific microbial cfDNA associated with chorioamnionitis was first detected in umbilical cord plasma and confirmed in the matched maternal plasma samples (n = 77 matched pairs) among 14 cases of histologically confirmed chorioamnionitis and one case of clinical chorioamnionitis; 63 paired samples were used as controls. A correlation of rank of a given microorganism across maternal plasma and matched umbilical cord plasma was used to assess whether signals found in umbilical cord plasma were also present in maternal plasma.

Results

Microbial DNA sequences associated with clinical and/or histological chorioamnionitis were enriched in maternal plasma in cases with suspected chorioamnionitis when compared to controls (12/14 microorganisms, p = 0.02). Analysis of the microbial cfDNA in umbilical cord plasma among the 1,251 microorganisms detectable with this assay identified Streptococcus mitis, Ureaplasma spp., and Mycoplasma spp. in cases of suspected chorioamnionitis. This assay also detected cfDNA from Lactobacillus spp. in controls. Comparison between maternal plasma and umbilical cord plasma confirmed these signatures were also present in maternal plasma. Unbiased analysis of microorganisms with significantly correlated signal between matched maternal plasma and umbilical cord plasma identified the above listed 3 microorganisms, all of which have previously been implicated in patients with chorioamnionitis (Mycoplasma hominis p = 0.0001; Ureaplasma parvum p = 0.002; Streptococcus mitis p = 0.007). These data show that the pathogen signal relevant for chorioamnionitis can be identified in both maternal and umbilical cord plasma.

Conclusion

This is the first report showing the detection of relevant microbial cell-free cfDNA in maternal plasma and umbilical cord plasma in patients with clinical and/or histological chorioamnionitis. These results may lead to the development of a specific assay to detect perinatal infections for targeted therapy to reduce early neonatal sepsis complications.

Evaluation of Clinical Outcomes of Sutureless vs Sutured Closure Techniques in Gastroschisis Repair

Importance

Sutureless gastroschisis repair offers an alternative to the traditional sutured method and has been associated with decreased intubation time. Published study results are inconsistent regarding the advantages of sutureless closure.

Objective

To compare the clinical outcomes of sutureless and sutured gastroschisis repair.

Design, Setting, and Participants

A single-center cohort review was performed of all consecutive patients (n = 97) who underwent gastroschisis repair from February 1, 2007, to April 30, 2017, at the University of California, San Francisco. Patients' medical records were evaluated for clinical characteristics and outcomes. Cases with incomplete data during initial hospitalization were excluded.

Main Outcomes and Measures

Length of hospital stay, time to full enteral feeds, total parenteral nutrition duration, days requiring intravenous analgesia, days intubated, wound infection rate, antibiotic treatment duration, rate of umbilical hernias that required an operation, and readmission rate.

Results

In total, 97 patients (47 [48%] were female and 50 [52%] were male with a mean [SD] age of 2.8 [2.8] days) underwent gastroschisis repair, of which 7 were excluded for incomplete medical record. Of the 90 patients included in the study, 50 (56%) underwent sutured closure and 40 (44%) underwent sutureless closure. No statistical difference was found between the sutured and sutureless groups in length of hospital stay (mean [SD] days, 43.9 [40.4] vs 36.7 [21.2]; P = .71), time to full enteral feeds (mean [SD] days, 31.4 [20.2] vs 27.9 [17.3]; P = .22), total parenteral nutrition duration (mean [SD] days, 33.5 [29.8] vs 27.4 [18.2]; P = .23), wound infection rates (14 [28%] vs 10 [25%]; P = .81), and readmission rates (5 [10%] vs 7 [18%]; P = .36). The sutureless group, compared with the sutured group, had substantially fewer days receiving antibiotics (mean [SD], 7.2 [6.4] vs 12.4 [13.2]; P = .003), fewer days intubated (mean [SD], 2.8 [3.3] vs 6.8 [1.3]; P = .001), fewer days receiving intravenous analgesia (mean [SD], 4.2 [4.0] vs 7.1 [4.5]; P = .003), and fewer patients that required silo reduction (25 [63%] vs 48 [96%]; P < .001). Sutureless closures, compared with the sutured technique, had considerably more umbilical hernias requiring surgical repair (5 [13%] vs 0; P = .02).

Conclusions and Relevance

Sutureless repair of gastroschisis appears to be associated with a statistically significant reduction in mechanical ventilation duration and pain medication requirements but may increase umbilical hernia risk. Multicenter randomized clinical trials are necessary to determine the true advantages of the sutureless approach.

Screening populations at high risk for soft tissue sarcoma and surveillance following soft tissue sarcoma resection

Soft tissue sarcomas (STS) are a rare and diverse group of tumors that affect both adult and pediatric populations. This review discusses current screening recommendations for populations at increased risk for STS, including those with genetic predispositions. We also review surveillance guidelines for those at risk for recurrence following curative-intent surgery.

Hand-assisted laparoscopic retroperitoneal donor nephrectomy: A single-institution experience of over 500 cases-Operative technique and clinical outcomes

OBJECTIVE

Although there are several variations of laparoscopic living-donor nephrectomies, there is no consensus as to the best technique. Our objective was to describe our technique and assess the outcomes of our approach to hand-assisted laparoscopic retroperitoneal donor nephrectomies.

METHODS

From July 2001 to October 2015, 507 consecutive hand-assisted laparoscopic retroperitoneal donor nephrectomies were performed. Their clinical information was retrospectively reviewed including warm ischemia time, skin incision to kidney ready time, estimated blood loss, adverse intraoperative events, and postoperative complications.

RESULTS

Mean incision time to kidney removal was 135 minutes (55-260), mean warm ischemia time was 125 seconds (30-390), and mean blood loss was 83 mL (20-500). Average length of stay was 3 days (1-6). There were no significant differences between left and right kidney donors based on demographics, length of hospital stay, or warm ischemia time. There were no conversions to open surgery. Complications occurred in 4.9% of patients (25/507), including 4 cases of perioperative bleeding.

CONCLUSIONS

This is a single-center series describing the safety and efficacy of the hand-assisted laparoscopic retroperitoneal donor nephrectomy for both right and left sides. It does not require intraperitoneal manipulation and allows for safe extraction of either kidney with minimal warm ischemia time.

Favorable outcomes after in utero transfusion in fetuses with alpha thalassemia major: a case series and review of the literature

OBJECTIVE

Alpha thalassemia major (ATM) is often fatal in utero due to severe hydrops fetalis. Although in utero transfusions (IUTs) are increasingly used to allow fetal survival in ATM, prenatal and postnatal outcomes are not well described.

METHODS

We retrospectively reviewed cases of ATM at our institution treated with consecutive IUT. Clinical records were reviewed for transfusion history, neurodevelopmental outcomes, anatomic abnormalities, survival to hematopoietic cell transplantation, and transfusion independence. A systematic review was performed, and additional reported cases are discussed.

RESULTS

Three patients who underwent IUT for ATM were identified, and review of the literature revealed 17 reported cases. Of patients who received IUT, reported neurodevelopmental deficits occurred in 29% (4/14) and anatomic abnormalities in 55% (11/20). Four patients eventually underwent successful hematopoietic cell transplantation. Transfusion volumes were less than suggested guidelines for other causes of fetal anemia in 91.7% of the transfusions.

CONCLUSION

This series demonstrates the potential for achieving full fetal development with normal neurologic outcomes in those affected by ATM. It provides support for continued patient and provider education about current benefits and risks of active prenatal therapy for fetuses with ATM, as well as continued research to optimize therapeutic strategies such as in utero transplantation. © 2016 John Wiley & Sons, Ltd.

Extracorporeal life support for nonimmune hydrops fetalis

A Down syndrome female born at 35 wk estimated gestational age with non-immune hydrops fetalis associated with a complete atrioventricular septal defect and large patent ductus arteriosus with hypoxemia, severe anasarca and hypotension was treated successfully with extracorporeal life support for severe cardiopulmonary failure leading to eventual hospital discharge and elective repair of her cardiac defect. The case demonstrates that extracorporeal life support may be an effective therapy when initiated early in patients with non-immune hydrops fetalis associated with significant cardiac abnormalities.