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BackgroundMetformin slows tumor growth and progression in vitro, and in combination with chemoradiotherapy, resulted in high overall survival in patients with head and neck cancer squamous cell carcinoma (HNSCC) in our phase 1 clinical trial (NCT02325401). Metformin is also postulated to activate an antitumor immune response. Here, we investigate immunologic effects of metformin on natural killer (NK) and natural killer T cells, including results from two phase I open-label studies in patients with HNSCC treated with metformin (NCT02325401, NCT02083692).MethodsPeripheral blood was collected before and after metformin treatment or from newly diagnosed patients with HNSCC. Peripheral immune cell phenotypes were evaluated using flow cytometry, cytokine expression by ELISA and/or IsoLight, and NK cell-mediated cytotoxicity was determined with a flow-based NK cell cytotoxicity assay (NKCA). Patient tumor immune infiltration before and after metformin treatment was analyzed with immunofluorescence. NK cells were treated with either vehicle or metformin and analyzed by RNA sequencing (RNA-seq). NK cells were then treated with inhibitors of significant pathways determined by RNA-seq and analyzed by NKCA, ELISA, and western blot analyses.ResultsIncreased peripheral NK cell activated populations were observed in patients treated with metformin. NK cell tumor infiltration was enhanced in patients with HNSCC treated with metformin preoperatively. Metformin increased antitumorigenic cytokines ex vivo, including significant increases in perforin. Metformin increased HNSCC NK cell cytotoxicity and inhibited the CXCL1 pathway while stimulating the STAT1 pathway within HNSCC NK cells. Exogenous CXCL1 prevented metformin-enhanced NK cell-mediated cytotoxicity. Metformin-mediated NK cell cytotoxicity was found to be AMP-activated protein kinase independent, but dependent on both mechanistic target of rapamycin and pSTAT1.ConclusionsOur data identifies a new role for metformin-mediated immune antitumorigenic function through NK cell-mediated cytotoxicity and downregulation of CXCL1 in HNSCC. These findings will inform future immunomodulating therapies in HNSCC.

IntroductionSurgery is the primary treatment for resectable, non-metastatic recurrent head and neck squamous cell carcinoma (HNSCC). We explore the safety and oncologic benefit of intraoperative Cesium-131 (Cs-131) brachytherapy combined with salvage local and/or regional surgical resection.Methods and materialsFindings were reported from a single arm multi-institutional prospective phase 1/2 trial involving surgery plus Cs-131 (surgery + Cs-131) treatment. The results of two retrospective cohorts-surgery alone and surgery plus intensity modulated radiation therapy (surgery + ReIMRT)-were also described. Included patients had recurrent HNSCC and radiation history. Safety, tumor re-occurrence, and survival were evaluated.ResultsForty-nine patients were enrolled in the surgery + Cs-131 prospective study. Grade 1 to 3 adverse events (AEs) occurred in 18 patients (37%), and grade 4 AEs occurred in 2 patients. Postoperative percutaneous endoscopic gastrostomy (PEG) tubes were needed in 10 surgery + Cs-131 patients (20%), and wound and vascular complications were observed in 12 patients (24%). No cases of osteoradionecrosis were reported in the surgery + Cs-131 cohort. We found a 49% 2-year disease-free survival at the site of treatment with a substantial number of patients (31%) developing metastatic disease, which led to a 31% overall survival at 5 years.ConclusionsAmong patients with local/regional recurrent HNSCC status-post radiation, surgery + Cs-131 demonstrated acceptable safety with compelling oncologic outcomes, as compared to historic control cohorts.Clinical trial registrationClinicalTrials.gov, identifiers NCT02794675 and NCT02467738.

Background: Medication related osteonecrosis of the jaw (MRONJ) requiring free flap (FF) reconstruction is uncommon with limited reported findings. Methods: Multicenter, retrospective case series of 49 consecutive adult patients presenting with advanced MRONJ requiring FF reconstruction from 2010 to 2022. Perioperative complications and outcomes were analyzed. Results: Eighty‐two percent (n = 40) of cases were of the mandible and 18% (n = 9) were of the maxilla. The mean follow‐up was 15 months (±19.6). The majority of FF survived (96%, n = 47). FF reconstructions of the maxilla were more likely to require postoperative debridement (56%, 95% CI [27, 81%] vs. 15%, 95% CI [7, 25%], p = 0.008) or develop intraoral bone exposure (56%, 95% CI [27, 81%] vs. 18%, 95% CI [9, 27%], p = 0.02). Most patients (71%, n = 35) received preoperative antibiotics which was associated with a higher rate of FF survival (100% vs. 86%, 95% CI [60, 96%], p = 0.02) and fewer complications. Conclusions: Patients undergoing FF reconstruction for MRONJ do well with high rates of FF success. MRONJ of the maxilla have a higher rate of some complications. Preoperative antibiotics correlated with higher FF survival and fewer postoperative complications. [ABSTRACT FROM AUTHOR]

Introduction: Oral cavity squamous cell carcinoma (OSCC) occurs most frequently in patients >60 years old with a history of tobacco and alcohol use. Epidemiological studies describe increased incidence of OSCC in younger adults (<45 years). Despite its poor prognosis, knowledge of OSCC tumor microenvironment (TME) characteristics in younger adults is scarce and could help inform possible resistance to emerging treatment options. Methods: Patients with OSCC were evaluated using TCGA-HNSC (n=121) and a stage and subsite-matched institutional cohort (n=8) to identify differential gene expression focusing on the extracellular matrix (ECM) and epithelialmesenchymal transition (EMT) processes in younger (=45 years) vs. older adults (=60 years). NanoString nCounter analysis was performed using isolated total RNA from formalin-fixed paraffin-embedded (FFPE) tumor samples. Stained tumor slides from young and old OSCC patients were evaluated for CD8+ Tcell counts using immunohistochemistry. Results: Younger OSCC patients demonstrated significantly increased expression of ECM remodeling and EMT process genes, as well as TME immunosuppression. Gene set enrichment analyses demonstrated increased ECM pathways and concurrent decreased immune pathways in young relative to old patients. Transcripts per million of genetic markers involved in ECM remodeling including LAMB3, VCAN, S100A9, COL5A1, and ITGB2 were significantly increased in tumors of younger vs. older patients (adjusted p-value < 0.10). Young patient TMEs demonstrated a 2.5-fold reduction in CD8+ T-cells as compared to older patients (p < 0.05). Conclusion: Differential gene expression impacting ECM remodeling and TME immunosuppression may contribute to disease progression in younger adult OSCC and has implications on response to evolving treatment modalities, such as immune checkpoint inhibitor therapy. [ABSTRACT FROM AUTHOR]

Background: There is sparse literature on the effect of preoperative immunotherapy on complications after surgery for primary head and neck squamous cell carcinoma (HNSCC). The objectives are to compare complication rates in patients receiving surgery with and without neoadjuvant immune checkpoint inhibitors (nICI) for primary HNSCC and to evaluate factors associated with increased odds of surgical complications. Methods: A retrospective review of patients who underwent ablation and free flap reconstruction or transoral robotic surgery (TORS) for primary HNSCC between 2017–2021 was conducted. Complications were compared between patients who underwent surgery with or without nICI before and after propensity score matching. Regression analysis to estimate odds ratios was performed. Results: A total of 463 patients met inclusion criteria. Free flap reconstruction constituted 28.9% of patients and TORS constituted 71.1% of patients. nICI was administered in 83 of 463 (17.9%) patients. There was no statistically significant difference in surgical, medical, or overall complications between patients receiving surgery with or without nICI. In the unmatched cohort, multivariable model identified non‐White race, former/current smoking history, free flap surgery, and perineural invasion as factors significantly associated with increased complications. In the matched cohort, multivariable model identified advanced age and free flap surgery as factors significantly associated with increased complications. Plain Language Summary: It is safe to give immunotherapy before major surgery in patients who have head and neck cancer.Advanced age, non‐White race, current/former smoking, free flap surgery, and perineural invasion may be associated with increased the odds of surgical complications. In this study, neoadjuvant immune checkpoint inhibitors (nICI) did not increase the risk of overall complications after adjusting for important confounders. Definitive surgery can be conducted safely after nICI. [ABSTRACT FROM AUTHOR]

Objective: To identify practices in microvascular techniques in routine and challenging scenarios. Study Design: Cross‐sectional study. Methods: A national survey addressing practices related to microvascular free flap reconstruction was distributed to AHNS members between October and November 2021. Results: The respondents encompassed 95 microvascular surgeons. Median years of practice was 6 (interquartile range, 2–13) and median flaps per year was 35 (22–50). Common practices in arterial anastomosis included limited cleaning of artery (84.2%), use of a double approximating clamp (64.2%), and use of interrupted suture (88.4%). Common practices in venous anastomosis included limited cleaning (89.5%), downsizing the coupler (53.7%), and coupling to two independent venous systems (47.4%). In arterial anastomosis, respondents felt that kinking (50.5%) and tension (24.2%) were the riskiest challenges. Kinking was handled by loose sutures or native tissue/dissolvable biomaterial to orient pedicle. Excess tension was handled by additional dissection. With regards to associated practices, most surgeons perform anastomosis after partial inset (52.6%), give aspirin immediately postoperatively (66.3%), reserve transfusion for hemodynamic instability (69.5%), and utilize intraoperative pressors when needed (72.6%). More senior surgeons reported placing more suture to address leaks (p = 0.004) and perform end to side anastomosis on larger vein in case of venous mismatch (p = 0.012). In cases of tension, higher volume surgeons perform more extensive dissection (p = 0.035) and end to side coupling (p = 0.029). Conclusions: This survey of AHNS members indicates patterns of microvascular techniques in routine and challenging scenarios. There exists a variation in approaches amongst surgeons based on volume and practice length. Level of Evidence: 5 Laryngoscope, 134:1265–1277, 2024 [ABSTRACT FROM AUTHOR]

Objective: To assess if there is increased risk of free flap failure in renal failure patients undergoing head and neck reconstruction. We seek to primarily assess free flap outcomes based on stages of chronic kidney disease (CKD) and secondarily determine increased risk for postoperative complications. Methods: Retrospective chart review was performed at five tertiary care centers. Patients were identified that had undergone microvascular free flap reconstruction of the head and neck with diagnosis of renal failure, classified as Stage 3 CKD or higher. Demographic data was collected. Outcomes in the postoperative period were examined. Results: Seventy‐three patients met inclusion criteria. The average patient age was 69 years with a male predominance (n = 48). The majority of patients had CKD Stage 3 (n = 52). Overall flap failure rate was 12.33% (n = 9, CKD stage 3 = 7.69%, CKD stage 4 = 30%, CKD stage 5 = 18%). There was an increased risk of flap failure on multivariate analysis for CKD stage 4/5 patients when compared to CKD 3 patients (p = 0.0095). When compared to matched controls, there was an increased risk of flap failure in CKD patients (p = 0.01) as well as an increased risk of overall complications (p < 0.0001). Conclusions: Patients with CKD undergoing head and neck reconstruction are at a higher risk of flap failure and overall complications. When comparing CKD stages there may be increased risk of flap failure in later stages of CKD compared to CKD 3. Appropriate patient counseling is recommended pre‐operatively in this patient population with consideration for regional flaps in the appropriate patient. Level of Evidence: 3 Laryngoscope, 134:688–694, 2024 [ABSTRACT FROM AUTHOR]