A nationwide propensity score analysis comparing ablation and resection for hepatocellular carcinoma.

BACKGROUND AND OBJECTIVES: Studies have reported ambiguous results regarding the efficacy of ablation for early-stage hepatocellular carcinoma (HCC). Our study compared outcomes of ablation versus resection for HCC ≤50 mm to identify tumor sizes that would most benefit from ablation in terms of long-term survival. METHODS: The National Cancer Database was queried for patients with stage I and II HCC ≤50 mm who underwent ablation or resection (2004-2018). Three cohorts were created based on tumor size: ≤20, 21-30, and 31-50 mm. A propensity score-matched survival analysis was performed using the Kaplan-Meier method. RESULTS: In total, 36.47% (n = 4263) and 63.53% (n = 7425) of patients underwent resection and ablation, respectively. After matching, resection was associated with a significant survival benefit compared to ablation (3-year survival: 78.13% vs. 67.64%; p < 0.0001) in patients with HCC of ≤20 mm. The impact of resection was even more striking among patients with HCC of 21-30 mm (3-year survival: 77.88% vs. 60.53%; p < 0.0001) and 31-50 mm (3-year survival: 67.21% vs. 48.55%; p < 0.0001). CONCLUSIONS: While resection offers a survival benefit over ablation in the treatment of early-stage HCC ≤50 mm, ablation may provide a feasible bridging strategy in patients awaiting transplantation.

Benefit and toxicity of programmed death-1 blockade vary by ethnicity in patients with advanced melanoma: an international multicentre observational study.

BACKGROUND: Programmed cell death receptor-1 (PD-1) monotherapy is a standard treatment for advanced cutaneous melanoma, but its efficacy and toxicity are defined in white populations and remain poorly characterized in other ethnic groups, such as East Asian, Hispanic and African. OBJECTIVES: To determine the efficacy and toxicity of PD-1 monotherapy in different ethnic groups. METHODS: Clinical data for patients with unresectable or advanced melanoma treated with anti-PD-1 monotherapy between 2009 and 2019 were collected retrospectively from five independent institutions in the USA, Australia and China. Tumour response, survival and immune-related adverse events (irAEs) were compared by ethnicity (white vs. East Asian/Hispanic/African) across different melanoma subtypes: nonacral cutaneous (NAC)/unknown primary (UP) and acral/mucosal/uveal. RESULTS: In total, 1135 patients were included. White patients had significantly higher objective response rate (ORR) [54%, 95% confidence interval (CI) 50-57% vs. 20%, 95% CI 13-28%; adjusted P < 0·001] and longer progression-free survival (14·2 months, 95% CI 10·7-20·3 vs. 5·4 months, 95% CI 4·5-7·0; adjusted P < 0·001) than East Asian, Hispanic and African patients in the NAC and UP subtypes. White ethnicity remained independently associated with a higher ORR (odds ratio 4·10, 95% CI 2·48-6·81; adjusted P < 0·001) and longer PFS (hazard ratio 0·58, 95% CI 0·46-0·74; adjusted P < 0·001) in multivariate analyses after adjustment for age, sex, primary anatomical location, metastasis stage, baseline lactate dehydrogenase level, mutational status and prior systemic treatment. White and East Asian/Hispanic/African patients shared similar ORR and progression-free survival in acral/mucosal/uveal melanomas. Similar melanoma-subtype-specific ethnic discrepancies were observed in complete response rate and overall survival. White patients had higher rates of gastrointestinal irAEs but lower rates of endocrine, liver and other rare types of irAEs. These differences in irAEs by ethnicity were not attributable to varying melanoma subtypes. CONCLUSIONS: Ethnic discrepancy in clinical benefit is specific to melanoma subtype, and East Asian, Hispanic and African patients with NAC and UP melanomas have poorer clinical benefits than previously recognized. The ethnic discrepancy in toxicity observed across different melanoma subtypes warrants an ethnicity-based irAE surveillance strategy. More research is needed to elucidate the molecular and immunological determinants of these differences. What is already known about this topic? There is a great difference in response to immunotherapy between different subtypes of melanoma (cutaneous, mucosal, acral and uveal) in patients with advanced disease. What does this study add? Our data show for the first time that there are differences between different ethnic groups in terms of both response and toxicity to immunotherapy beyond the well-appreciated discrepancies due to melanoma subtype.

Use of immunotherapy and surgery for stage IV melanoma.

BACKGROUND: Immunotherapy for stage IV melanoma has dramatically changed the overall prognosis and treatment strategies. The aim of this study was to evaluate whether changes in systemic immunotherapy options have significantly altered surgical resection rates for patients with stage IV melanoma. METHODS: The National Cancer Database (2004-2015) was used to perform a difference-in-difference analysis to evaluate whether the rate of surgical resection of metastatic disease for stage IV melanoma differed with the use of immunotherapy in the checkpoint inhibitor era in comparison with the use of immunotherapy in the pre-checkpoint inhibitor era. An adjusted difference-in-difference analysis stratified by facility type was performed. An adjusted Poisson regression analysis evaluated predictors of surgical resection in patients with stage IV melanoma who received immunotherapy. RESULTS: There were 14,433 patients with stage IV melanoma (median age, 66 years [interquartile range, 56-76 years]; female, 31.7%), and of all patients in the checkpoint inhibitor era (n = 7,524), 25% (n = 1,879) received immunotherapy. Patients with stage IV disease who received immunotherapy in the checkpoint inhibitor era were more likely to be younger, be healthier, have private insurance, come from upper income quartiles, and be treated at academic programs. A difference-in-difference analysis revealed similar rates of surgical resection of metastatic disease with the use of immunotherapy in the checkpoint inhibitor era and the pre-checkpoint inhibitor era, regardless of facility type. CONCLUSIONS: The distribution of immunotherapy was unequal among patients with stage IV melanoma. Across all facilities, the rates of surgical resection of metastatic disease for stage IV melanoma did not differ with the use of immunotherapy between the checkpoint inhibitor era and the pre-checkpoint inhibitor era.

Genome-wide prediction of synthetic rescue mediators of resistance to targeted and immunotherapy.

Most patients with advanced cancer eventually acquire resistance to targeted therapies, spurring extensive efforts to identify molecular events mediating therapy resistance. Many of these events involve synthetic rescue (SR) interactions, where the reduction in cancer cell viability caused by targeted gene inactivation is rescued by an adaptive alteration of another gene (the rescuer). Here, we perform a genome-wide in silico prediction of SR rescuer genes by analyzing tumor transcriptomics and survival data of 10,000 TCGA cancer patients. Predicted SR interactions are validated in new experimental screens. We show that SR interactions can successfully predict cancer patients' response and emerging resistance. Inhibiting predicted rescuer genes sensitizes resistant cancer cells to therapies synergistically, providing initial leads for developing combinatorial approaches to overcome resistance proactively. Finally, we show that the SR analysis of melanoma patients successfully identifies known mediators of resistance to immunotherapy and predicts novel rescuers.

The Role of Venous and Arterial Resection in Pancreatic Cancer Surgery.

Pancreatic cancer continues to carry a dismal prognosis with the majority of patients presenting at advanced stages of disease. Complete surgical resection remains essential for prolonging survival and increasing the possibility of cure. However, few patients will be resectable at diagnosis, with a significant portion presenting with borderline or locally advanced disease. The addition of vascular resection and reconstruction at the time of pancreatectomy enables expansion of the patient population able to undergo resection with curative intent and achieve tumor-free margins. This review provides an overview of the literature regarding the role of venous and arterial resection in the treatment of pancreatic cancer, with a focus on outcomes including survival, morbidity, and mortality.

Pathological Margin Clearance and Survival After Pancreaticoduodenectomy in a US and European Pancreatic Center.

BACKGROUND: The optimal definition of a margin-negative resection and its exact prognostic significance on survival in resected pancreatic adenocarcinoma remains unknown. This study was designed to assess the relationship between pathological margin clearance, margin type, and survival. METHODS: Patients who underwent pancreaticoduodenectomy with curative intent at two academic institutions, in Amsterdam, the Netherlands, and Boston, Massachusetts, between 2000 and 2014 were retrospectively evaluated. Overall survival, recurrence rates, and progression-free survival (PFS) were assessed by Kaplan-Meier estimates and multivariate Cox proportional hazards analysis, according to pathological margin clearance and type of margin involved. RESULTS: Of 531 patients identified, the median PFS was 12.9, 15.4, and 24.1 months, and the median overall survival was 17.4, 22.9, and 27.7 months for margin clearances of 0, < 1, and ≥1 mm, respectively (all log-rank p < 0.001). On multivariate analysis, patients with a margin clearance of ≥1 mm demonstrated a survival advantage relative to those with 0 mm clearance [hazard ratio (HR) 0.71, p < 0.01], whereas survival was comparable for patients with a margin clearance of < 1 mm versus 0 mm (HR: 0.93, p = 0.60). Patients with involvement (0 or < 1 mm margin clearance) of the SMV/PV margin demonstrated prolonged median overall survival (25.7 months) relative to those with SMA involvement (17.5 months). CONCLUSIONS: In patients undergoing pancreaticoduodenectomy for pancreatic adenocarcinoma, a margin clearance of ≥1 mm correlates with improved survival relative to < 1 mm clearance and may be a more accurate predictor of a complete margin-negative resection in pancreatic cancer. The type of margin involved also appears to impact survival.

Neoadjuvant therapy affects margins and margins affect all: perioperative and survival outcomes in resected pancreatic adenocarcinoma.

BACKGROUND: Resection margin status is an important prognostic factor in pancreatic cancer; however, the impact of positive resection margins in those who received neoadjuvant therapy remains unclear. The current study investigates the prognostic impact of resection margin status after neoadjuvant therapy and pancreaticoduodenectomy for patients with pancreatic adenocarcinoma. METHODS: Patients who underwent pancreaticoduodenectomy for pancreatic adenocarcinoma between 2006 and 2013 were identified from the National Cancer Database. Multivariable logistic regression analysis was utilized to examine the predictive value of neoadjuvant therapy for resection margin status. Long-term outcomes were compared using a Cox proportional hazards model. RESULTS: 7917 patients were identified in total: 1077 (13.6%) and 6840 (86.4%) patients received neoadjuvant therapy and upfront surgery, respectively. Upfront surgery was independently predictive of a positive margin (25.7% vs. 17.7%; OR, 1.54) compared to neoadjuvant therapy. After receipt of neoadjuvant therapy, positive margins (median overall survival, 18.5 vs. 25.9 months; HR, 1.58) remained significantly associated with poor survival on multivariable analysis. DISCUSSION: While neoadjuvant therapy is associated with decreased R1/R2-resection rates after pancreaticoduodenectomy, the poor prognostic impact of positive margins is not abrogated by neoadjuvant therapy, stressing the need for complete tumor clearance and postoperative treatment even after neoadjuvant therapy.

Unique predictors and economic burden of superficial and deep/organ space surgical site infections following pancreatectomy.

BACKGROUND: Surgical site infections (SSIs) are common following pancreatectomy and associated with significant morbidity and economic burden. We sought to identify distinct predictors for superficial versus deep/organ space SSIs and their effects on surgical outcomes. METHODS: ACS-NSQIP targeted pancreatectomy 2014 and 2015 databases were queried. Univariate and multivariate models were developed for both types of SSI, length of stay (LOS), and readmission. Costs were estimated based on Centers for Medicare & Medicaid Services (CMS) recommendations. RESULTS: Of 8093 patients, there were 422 (5.2%) superficial and 1005 (12.4%) deep/organ space SSIs. On multivariate analyses, preoperative biliary stenting was predictive only for superficial SSI (OR: 2.21), while BMI of 25-29.9 (OR: 1.25) and BMI ≥30 kg/m2 (OR: 1.53), pancreatic duct size <3 mm (OR: 1.30), and intermediate (OR: 1.67) versus hard gland texture were predictors of deep/organ-space SSI. Superficial and deep/organ space SSIs were independent predictors of prolonged LOS (OR: 1.74 vs 1.80) and readmission (OR: 2.59 vs 6.57). Additional readmission costs per patient secondary to superficial SSI and deep/organ space SSI were $7661.37 and $18,409.42, respectively. CONCLUSION: Deep/organ space SSI contributes more profoundly to prolonged hospital stay, readmission, and additional costs, suggesting that strategies should focus on preferential prevention of deep/organ space infections.

Stereotactic body radiotherapy for unresected pancreatic cancer: A nationwide review.

BACKGROUND: The role of conventional radiotherapy in the management of pancreatic cancer has yet to be elucidated. Over the past decade, stereotactic body radiotherapy (SBRT) has emerged as a novel therapeutic option in pancreatic cancer care. This study evaluated the survival impact of SBRT on patients with unresected pancreatic cancer. METHODS: The National Cancer Data Base was queried for unresected patients who received chemotherapy for nonmetastatic pancreatic adenocarcinoma between 2004 and 2012. Four treatment groups were identified: chemotherapy alone, chemotherapy combined with external-beam radiotherapy (EBRT), chemotherapy combined with intensity-modulated radiotherapy (IMRT), and chemotherapy combined with SBRT. Propensity score models predicting the odds of receiving SBRT were created to control for potential selection bias, and patients were matched by propensity scores. The survival analysis was performed with the Kaplan-Meier method. RESULTS: A total of 14,331 patients met the inclusion criteria. Chemotherapy alone was delivered to 5464 patients (38.1%); 6418 (44.8%), 322 (2.3%), and 2127 (14.8%) received chemotherapy along with EBRT, IMRT, and SBRT, respectively. The unadjusted median survival before matching was 9.9, 10.9, 12.0, and 13.9 months for patients treated with chemotherapy, EBRT, IMRT, and SBRT, respectively. In separate matched analyses, SBRT remained superior to chemotherapy alone (log-rank P < .0001) and EBRT (log-rank P = .0180). After matching, survival did not differ between patients receiving IMRT and patients receiving SBRT (log-rank P = .0492). CONCLUSIONS: SBRT is associated with a significantly better outcome than chemotherapy alone or in conjunction with traditional EBRT. These results support the idea that SBRT is a promising treatment approach for patients with unresected pancreatic cancer. Cancer 2017;123:4158-4167. © 2017 American Cancer Society.

Surgical Management of Gallbladder Cancer: Simple Versus Extended Cholecystectomy and the Role of Adjuvant Therapy.

OBJECTIVE: To assess if simple cholecystectomy with adjuvant therapy could provide outcomes comparable to extended cholecystectomy. BACKGROUND: Current guidelines recommend extended/radical cholecystectomy for T2/T3 gallbladder cancer; however, many tumors are discovered incidentally at laparoscopic cholecystectomy. METHODS: The national Cancer Data Base 2004 to 2014 was queried for patients with pT2/T3 gallbladder adenocarcinoma who underwent resection. Adjuvant therapy was defined as chemotherapy, with or without radiotherapy, within 90 days of surgery. Baseline characteristics and overall survival were compared by χ and Kaplan-Meier method, respectively. One-to-one propensity score matching for receipt of adjuvant therapy was used to account for potential selection bias. RESULTS: A total of 6825 patients were identified. Diagnosis was made predominantly (78.9%) at the time of surgery or on pathology; 31.8% (2168) received adjuvant therapy. The majority, 88.8% (6060), had a simple cholecystectomy. Patients who received adjuvant therapy versus surgery alone were more likely to: be younger, privately insured, have no comorbidities, pT3 disease, positive lymph nodes, positive resection margins, and extended cholecystectomy. After matching, median survival was significantly longer for extended cholecystectomy with adjuvant therapy (23.3 months) than cholecystectomy with adjuvant therapy (16.4 months), which was significantly longer than either simple (12.4 months) or extended (10.7 months) cholecystectomy alone (all log-rank P<0.001). CONCLUSIONS: Adjuvant therapy prolongs survival after resection of T2/T3 tumors. Simple cholecystectomy with adjuvant therapy appears to be superior to extended resection alone in the short term and may serve as a potential alternative to re-resection in select high-risk individuals.

Hemorrhage after pancreaticoduodenectomy: does timing matter?

BACKGROUND: Hemorrhage after pancreaticoduodenectomy is a potentially fatal complication. We retrospectively reviewed state-wide data to evaluate incidence, type of hemorrhage, treatment modalities, and outcomes. METHODS: Healthcare Cost and Utilization Project's Florida State Inpatient Database was queried 2007-2011 for patients undergoing pancreaticoduodenectomy. Characteristics and outcomes were compared by χ2. Multivariate logistic regression model was generated for risk of hemorrhage during index visit. RESULTS: Of 2548 patients, 217 (8.5%) developed post-operative hemorrhage during their index visit with 139 (64.0%) requiring angiographic, endoscopic, or operative intervention. Overall mortality during index visit was 5.7% (146) - significantly higher in those patients who had post-operative hemorrhage (24.9%) vs not (4.0%) (p < 0.0001). Mortality was significantly higher when post-operative hemorrhage occurred during the second (POD 8-14) vs first (POD 0-7) week at 15/28 vs 16/74, respectively (p = 0.007). On multivariate analysis, male sex (OR 1.56, p = 0.003), vascular resection (OR 1.88, p = 0.017), very low hospital volume (≤7 PD/year; OR 1.62, p = 0.016), and post-operative intra-abdominal/wound infection (OR 2.31, p < 0.0001) were independent predictors for risk of hemorrhage during index visit. CONCLUSIONS: Hemorrhage following pancreaticoduodenectomy remains common, resulting in significantly increased mortality. Hemorrhage during the second post-operative week carries approximately double the mortality of early bleeding, suggesting different etiologies requiring differing treatment approaches.

Role of the CaMKII/NMDA receptor complex in the maintenance of synaptic strength.

During long-term potentiation (LTP), synapses undergo stable changes in synaptic strength. The molecular memory processes that maintain strength have not been identified. One hypothesis is that the complex formed by the Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) and the NMDA-type glutamate receptor (NMDAR) is a molecular memory at the synapse. To establish a molecule as a molecular memory, it must be shown that interfering with the molecule produces a persistent reversal of LTP. We used the CN class of peptides that inhibit CaMKII binding to the NR2B subunit in vitro to test this prediction in rat hippocampal slices. We found that CN peptides can reverse saturated LTP, allowing additional LTP to be induced. The peptide also produced a persistent reduction in basal transmission. We then tested whether CN compounds actually affect CaMKII binding in living cells. Application of CN peptide to slice cultures reduced the amount of CaMKII concentrated in spines, consistent with delocalization of the kinase from a binding partner in the spine. To more specifically assay the binding of CaMKII to the NMDAR, we used coimmunoprecipitation methods. We found that CN peptide decreased synaptic strength only at concentrations necessary to disrupt the CaMKII/NMDAR complex, but not at lower concentrations sufficient to inhibit CaMKII activity. Importantly, both the reduction of the complex and the reduction of synaptic strength persisted after removal of the inhibitor. These results support the hypothesis that the CaMKII/NMDAR complex has switch-like properties that are important in the maintenance of synaptic strength.

Disparities in access to care among patients with appendiceal or colorectal cancer and peritoneal metastases: A medicare insurance-based study in the United States.

Background: Prior studies attempting to identify disparities in the care of patients with appendiceal (AC) or colorectal cancer (CRC) with peritoneal metastasis (PM) are limited to single-institution, highly selected patient populations. This observational cohort study sought to identify factors associated with specialty care for Medicare beneficiaries with AC/CRC-PM. Materials and methods: Patients >65 years old in the United States diagnosed with AC/CRC and isolated PM were identified within the Medicare Standard Analytic File (2013-2017). Mixed-effects analyses assessed patient factors associated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) and outpatient consultation with a peritoneal surface malignancy (PSM) surgeon, and Cox proportional-hazards analysis compared 3-year overall survival (OS) between patients receiving CRS/HIPEC versus systemic therapy alone. Results: Among 7,653 patients, only 250 (3.3%) underwent CRS/HIPEC. Among those individuals who did not undergo CRS/HIPEC (N=7,403), only 475 (6.4%) had outpatient consultation with a PSM surgeon. Patient factors independently associated with lower odds of CRS/HIPEC and PSM surgery consultation included older age, greater comorbidity burden, higher social vulnerability index, and further distance from a PSM center (p<0.05). CRS/HIPEC was independently associated with better 3-year OS compared with systemic therapy alone (HR=0.29, 95%CI=0.21-0.38). Conclusion: An exceedingly small proportion of Medicare beneficiaries with AC/CRC-PM undergo CRS/HIPEC or even have an outpatient consultation with a PSM surgeon. Significant disparities in treatment and access to care exist for patients with higher levels of social vulnerability and those that live further away from a PSM center. Future research and interventions should focus on improving access to care for these at-risk patient populations.

Fine Needle Aspiration Cytology of Malignant Digestive System Gastrointestinal Neuroectodermal Tumor in a Lymph Node Metastasis from a Previously Diagnosed Liver Primary: A Case Report and Review of Literature.

Malignant gastrointestinal neuroectodermal tumor (GNET) is an extremely rare neoplasm. Immunohistochemically, GNET typically demonstrates neural differentiation but lacks melanocytic differentiation, making it distinct from clear cell sarcoma of the soft tissues (CCS). Herein we report for the first time the cytomorphologic features of lymph node metastasis from presumably liver GNET. A 36-year-old female presented with fevers, night sweats, loss of appetite, and a 20-lbs weight loss. Radiographic imaging showed a 13 cm heterogeneously enhancing mass in the right lobe of the liver and a hypermetabolic 0.9 cm periportal lymph node on positron emission tomography-computed tomography (PET/CT). Initially, a CT-guided liver biopsy was performed followed by right hepatic lobectomy and portal lymphadenectomy. The liver biopsy and resection showed an S100-protein and SOX10 positive malignant neoplasm and genomic profiling of liver biopsy revealed EWSR1-CREB1gene rearrangement. These findings in conjunction with the morphologic and immunohistochemical profile were diagnostic of GNET. Two months later, she presented with recurrent lymphadenopathy in the upper abdomen. Fine needle aspiration of the periportal nodal mass revealed single and clusters of primitive, large to medium-sized neoplastic cells with round to oval nuclei, high nuclear-cytoplasmic ratio, vesicular chromatin, and prominent nucleoli. The tumor cells were S100 protein and SOX10 positive, consistent with metastasis of the patient's recently diagnosed malignant digestive system GNET. Palliative chemotherapy was administered but the patient died a few days later, 4 months from the initial diagnosis. Awareness of this entity and judicial use of ancillary studies including molecular testing are essential for achieving accurate diagnosis.

Neutrophils Extracellular Traps Inhibition Improves PD-1 Blockade Immunotherapy in Colorectal Cancer.

Immune checkpoint inhibitors can improve the prognosis of patients with advanced malignancy; however, only a small subset of advanced colorectal cancer patients in microsatellite-instability-high or mismatch-repair-deficient colorectal cancer can benefit from immunotherapy. Unfortunately, the mechanism behind this ineffectiveness is unclear. The tumor microenvironment plays a critical role in cancer immunity, and may contribute to the inhibition of immune checkpoint inhibitors and other novel immunotherapies in patients with advanced cancer. Herein, we demonstrate that the DNase I enzyme plays a pivotal role in the degradation of NETs, significantly dampening the resistance to anti-PD-1 blockade in a mouse colorectal cancer model by attenuating tumor growth. Remarkably, DNase I decreases tumor-associated neutrophils and the formation of MC38 tumor cell-induced neutrophil extracellular trap formation in vivo. Mechanistically, the inhibition of neutrophil extracellular traps with DNase I results in the reversal of anti-PD-1 blockade resistance through increasing CD8+ T cell infiltration and cytotoxicity. These findings signify a novel approach to targeting the tumor microenvironment using DNase I alone or in combination with immune checkpoint inhibitors.

Radiological dynamics and SITC-defined resistance types of advanced melanoma during anti-PD-1 monotherapy: an independent single-blind observational study on an international cohort.

BACKGROUND: Although the Society for Immunotherapy of Cancer (SITC) Immunotherapy Resistance Taskforce recently defined primary and secondary resistance to anti-programmed cell death protein 1 (anti-PD-1) therapy, there is lack of real-world data regarding differences in these resistance subtypes with respect to radiological dynamics and clinical manifestations. METHODS: We performed single-blind re-evaluations of radiological images by independent radiologists on a retrospectively assembled cohort of patients with advanced melanoma (n=254, median follow-up 31 months) receiving anti-PD-1 monotherapy at Massachusetts General Hospital and Peking University Cancer Hospital. Radiological characteristics and timing at multiple crucial time points were analyzed and correlated with each other and with survival. Primary and secondary resistance was defined as per the SITC Immunotherapy Resistance Taskforce definitions. RESULTS: The most significant target lesion measurement change took place within the first 3 months after anti-PD-1 initiation. Patients with stable disease with versus without tumor shrinkage at the initial evaluation exhibited distinct disease trajectory, as the rate of further upgrade to a partial or complete remission (CR/PR) was 44% and 0%, respectively. Eleven per cent of PR patients ultimately achieved a CR. In multivariate analyses, deeper response depth was independently associated with a more limited progression pattern, fewer involved organs, lower tumor burden, slower growth rate at disease progression (PD) (all p≤0.001), and longer post-progression survival (PPS) (bivariate analysis, p=0.005). Compared with primary resistance, secondary resistance was associated with less widespread PD pattern, lower tumor burden and slower tumor growth (all p≤0.001). Patients with secondary resistance were less likely to receive further systemic therapy (28% vs 57%, p<0.001) yet had significantly better PPS (HR 0.503, 95% CI 0.288 to 0.879, p=0.02). CONCLUSIONS: Radiological dynamics were variable, yet significantly correlated with survival outcomes. SITC-defined primary and secondary resistance are distinct clinical manifestations in patients with melanoma, suggesting the possibility of resistance-type-based therapeutic decision-making and clinical trial design, once further validated by future prospective studies.

Early Use of High-Dose Glucocorticoid for the Management of irAE Is Associated with Poorer Survival in Patients with Advanced Melanoma Treated with Anti-PD-1 Monotherapy.

PURPOSE: Programmed cell death receptor-1 (PD-1) inhibitors are frontline therapy in advanced melanoma. Severe immune-related adverse effects (irAEs) often require immunosuppressive treatment with glucocorticoids (GCCs), but GCC use and its correlation with patient survival outcomes during anti-PD-1 monotherapy remains unclear. EXPERIMENTAL DESIGN: In this multicenter retrospective analysis, patients treated with anti-PD-1 monotherapy between 2009 and 2019 and detailed GCC use, data were identified from five independent cohorts, with median follow-up time of 206 weeks. IrAEs were tracked from the initiation of anti-PD-1 until disease progression, initiation of a new therapy, or last follow-up. Correlations between irAEs, GCC use, and survival outcomes were analyzed. RESULTS: Of the entire cohort of 947 patients, 509 (54%) developed irAEs. In the MGH cohort [irAE(+) n = 90], early-onset irAE (within 8 weeks of anti-PD-1 initiation) with high-dose GCC use (≥60-mg prednisone equivalent once a day) was independently associated with poorer post-irAE PFS/OS (progression-free survival/overall survival) [post-irAE PFS: HR, 5.37; 95% confidence interval (CI), 2.10-13.70; P < 0.001; post-irAE OS: HR, 5.95; 95% CI, 2.20-16.09; P < 0.001] compared with irAEs without early high-dose GCC use. These findings were validated in the combined validation cohort [irAE(+) n = 419, post-irAE PFS: HR, 1.69; 95% CI, 1.04-2.76; P = 0.04; post-irAE OS: HR, 1.97; 95% CI, 1.15-3.39; P = 0.01]. Similar findings were also observed in the 26-week landmark analysis for post-irAE-PFS but not for post-irAE-OS. A sensitivity analysis using accumulated GCC exposure as the measurement achieved similar results. CONCLUSIONS: Early high-dose GCC use was associated with poorer PFS and OS after irAE onset. Judicious use of GCC early during anti-PD-1 monotherapy should be considered. Further prospective randomized control clinical trials designed to explore alternative irAE management options are warranted.

Evolution of delayed resistance to immunotherapy in a melanoma responder.

Despite initial responses1-3, most melanoma patients develop resistance4 to immune checkpoint blockade (ICB). To understand the evolution of resistance, we studied 37 tumor samples over 9 years from a patient with metastatic melanoma with complete clinical response to ICB followed by delayed recurrence and death. Phylogenetic analysis revealed co-evolution of seven lineages with multiple convergent, but independent resistance-associated alterations. All recurrent tumors emerged from a lineage characterized by loss of chromosome 15q, with post-treatment clones acquiring additional genomic driver events. Deconvolution of bulk RNA sequencing and highly multiplexed immunofluorescence (t-CyCIF) revealed differences in immune composition among different lineages. Imaging revealed a vasculogenic mimicry phenotype in NGFRhi tumor cells with high PD-L1 expression in close proximity to immune cells. Rapid autopsy demonstrated two distinct NGFR spatial patterns with high polarity and proximity to immune cells in subcutaneous tumors versus a diffuse spatial pattern in lung tumors, suggesting different roles of this neural-crest-like program in different tumor microenvironments. Broadly, this study establishes a high-resolution map of the evolutionary dynamics of resistance to ICB, characterizes a de-differentiated neural-crest tumor population in melanoma immunotherapy resistance and describes site-specific differences in tumor-immune interactions via longitudinal analysis of a patient with melanoma with an unusual clinical course.

Epitope spreading toward wild-type melanocyte-lineage antigens rescues suboptimal immune checkpoint blockade responses.

Although immune checkpoint inhibitors (ICIs), such as anti-programmed cell death protein-1 (PD-1), can deliver durable antitumor effects, most patients with cancer fail to respond. Recent studies suggest that ICI efficacy correlates with a higher load of tumor-specific neoantigens and development of vitiligo in patients with melanoma. Here, we report that patients with low melanoma neoantigen burdens who responded to ICI had tumors with higher expression of pigmentation-related genes. Moreover, expansion of peripheral blood CD8+ T cell populations specific for melanocyte antigens was observed only in patients who responded to anti-PD-1 therapy, suggesting that ICI can promote breakdown of tolerance toward tumor-lineage self-antigens. In a mouse model of poorly immunogenic melanomas, spreading of epitope recognition toward wild-type melanocyte antigens was associated with markedly improved anti-PD-1 efficacy in two independent approaches: introduction of neoantigens by ultraviolet (UV) B radiation mutagenesis or the therapeutic combination of ablative fractional photothermolysis plus imiquimod. Complete responses against UV mutation-bearing tumors after anti-PD-1 resulted in protection from subsequent engraftment of melanomas lacking any shared neoantigens, as well as pancreatic adenocarcinomas forcibly overexpressing melanocyte-lineage antigens. Our data demonstrate that somatic mutations are sufficient to provoke strong antitumor responses after checkpoint blockade, but long-term responses are not restricted to these putative neoantigens. Epitope spreading toward T cell recognition of wild-type tumor-lineage self-antigens represents a common pathway for successful response to ICI, which can be evoked in neoantigen-deficient tumors by combination therapy with ablative fractional photothermolysis and imiquimod.

Plasma-derived extracellular vesicle analysis and deconvolution enable prediction and tracking of melanoma checkpoint blockade outcome.

Immune checkpoint inhibitors (ICIs) show promise, but most patients do not respond. We identify and validate biomarkers from extracellular vesicles (EVs), allowing non-invasive monitoring of tumor- intrinsic and host immune status, as well as a prediction of ICI response. We undertook transcriptomic profiling of plasma-derived EVs and tumors from 50 patients with metastatic melanoma receiving ICI, and validated with an independent EV-only cohort of 30 patients. Plasma-derived EV and tumor transcriptomes correlate. EV profiles reveal drivers of ICI resistance and melanoma progression, exhibit differentially expressed genes/pathways, and correlate with clinical response to ICI. We created a Bayesian probabilistic deconvolution model to estimate contributions from tumor and non-tumor sources, enabling interpretation of differentially expressed genes/pathways. EV RNA-seq mutations also segregated ICI response. EVs serve as a non-invasive biomarker to jointly probe tumor-intrinsic and immune changes to ICI, function as predictive markers of ICI responsiveness, and monitor tumor persistence and immune activation.