Immunohistochemical assessment of HER2 low breast cancer: interobserver reproducibility and correlation with digital image analysis.

PURPOSE: The recent findings from the DESTINY-Breast04 trial highlighted the clinical importance of distinguishing between HER2 immunohistochemistry (IHC) scores 0 and 1 + in metastatic breast cancer (BC). However, pathologist interpretation of HER2 IHC scoring is subjective, and standardized methodology is needed. We evaluated the consistency of HER2 IHC scoring among pathologists and the accuracy of digital image analysis (DIA) in interpreting HER2 IHC staining in cases of HER2-low BC. METHODS: Fifty whole-slide biopsies of BC with HER2 IHC staining were evaluated, comprising 25 cases originally reported as IHC score 0 and 25 as 1 +. These slides were digitally scanned. Six pathologists with breast expertise independently reviewed and scored the scanned images, and DIA was applied. Agreement among pathologists and concordance between pathologist scores and DIA results were statistically analyzed using Kendall coefficient of concordance (W) tests. RESULTS: Substantial agreement among at least five of the six pathologists was found for 18 of the score 0 cases (72%) and 15 of the score 1 + cases (60%), indicating excellent interobserver agreement (W = 0.828). DIA scores were highly concordant with pathologist scores in 96% of cases (47/49), indicating excellent concordance (W = 0.959). CONCLUSION: Although breast subspecialty pathologists were relatively consistent in evaluating BC with HER2 IHC scores of 0 and 1 +, DIA may be a reliable supplementary tool to enhance the standardization and quantification of HER2 IHC assessment, especially in challenging cases where results may be ambiguous (i.e., scores 0-1 +). These findings hold promise for improving the accuracy and consistency of HER2 testing.

The immunogenomic landscape of resected intrahepatic cholangiocarcinoma.

BACKGROUND AND AIMS: Cholangiocarcinoma (CCA) is a deadly and highly therapy-refractory cancer of the bile ducts, with early results from immune checkpoint blockade trials showing limited responses. Whereas recent molecular assessments have made bulk characterizations of immune profiles and their genomic correlates, spatial assessments may reveal actionable insights. APPROACH AND RESULTS: Here, we have integrated immune checkpoint-directed immunohistochemistry with next-generation sequencing of resected intrahepatic CCA samples from 96 patients. We found that both T-cell and immune checkpoint markers are enriched at the tumor margins compared to the tumor center. Using two approaches, we identify high programmed cell death protein 1 or lymphocyte-activation gene 3 and low CD3/CD4/inducible T-cell costimulator specifically in the tumor center as associated with poor survival. Moreover, loss-of-function BRCA1-associated protein-1 mutations are associated with and cause elevated expression of the immunosuppressive checkpoint marker, B7 homolog 4. CONCLUSIONS: This study provides a foundation on which to rationally improve and tailor immunotherapy approaches for this difficult-to-treat disease.

Treatment Variation and Long-Term Outcomes of Low-Grade Appendiceal Neoplasms.

BACKGROUND: Heterogenous nomenclature describing appendiceal neoplasms has added to uncertainty around their appropriate treatment. Although a recent consensus has established the term low-grade appendiceal neoplasm (LAMN), we hypothesize that significant variation remains in the treatment of LAMNs. METHODS: We retrospectively reviewed our prospectively maintained appendiceal registry, identifying patients with LAMNs from 2009 to 2019. We assessed variability in treatment, including whether patients underwent colectomy, spread of disease at presentation, and long-term outcomes. RESULTS: Of 136 patients with LAMNs, 88 (35%) presented with localized disease and 48 (35%) with disseminated peritoneal disease. Median follow-up was 2.9 years (IQR 1.9-4.4), and 120 (88%) patients underwent pre-referral surgery. Among 26 pre-referral colectomy patients, 23 (88%) were performed for perceived oncologic need/nodal evaluation; no nodal metastases were identified. In patients with resected LAMNs without radiographic evidence of disseminated disease, 41 (47%) underwent second look diagnostic laparoscopy (DL) to evaluate for occult metastases. No peritoneal metastases were identified. Patients with disseminated disease were treated with cytoreductive surgery/heated intraperitoneal chemotherapy (CRS/HIPEC). For patients undergoing CRS/HIPEC, 5-year recurrence-free survival was 94% (95% CI 81-98%). For patients with localized disease, 5-year RFS was 98% (95% CI 85-99%). CONCLUSIONS: Significant variation exists in treatment patterns for LAMNs, particularly prior to referral to a high-volume center. Patients frequently underwent colectomy without apparent oncologic benefit. In the current era of high-quality cross sectional imaging, routine use of DL has low yield and is not recommended. Recurrence in this population is rare, and low-intensity surveillance can be offered. Overall prognosis is excellent, even with peritoneal disease.

Prognostic significance of acellular mucin in patients undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) for appendiceal neoplasms.

INTRODUCTION: Appendiceal neoplasms have a propensity for peritoneal dissemination. The standard of care for select individuals is CRS/HIPEC. In the current 8th AJCC Staging system, a finding of only intraperitoneal acellular mucin (M1a) is classified as Stage IVa. There is concern that the current AJCC system may over-stage patients. METHODS: This was a single-institution retrospective review of 164 cases of mucinous appendiceal neoplasm. Patients undergoing CRS/HIPEC with M1a disease were compared to patients with peritoneal deposits containing tumor cells (well-differentiated adenocarcinoma; low-grade mucinous carcinoma peritonei-M1b,G1). Overall and recurrence-free survival were assessed. RESULTS: Median age was 51 years, 70% were female, and 75% White. Sixty-four patients had M1a disease and 100 M1b,G1 disease. M1a disease had a lower median PCI score (11 vs. 20, p = .0001) and a higher rate of complete CRS (62% vs. 50%, p = .021). Median follow-up was 7.6 years (IQR 5.6-10.5 years). For M1a disease, there were no recurrences and only one patient died during the study interval. In comparison, for M1b disease, 66/100 (66%) recurred with a 5-year RFS of 40.5% (HR 8.0, 95% CI 4.9-15.1, p < .0001), and 31/100 (31%) died with a 5-year OS of 84.8% (HR 4.5, 95% CI 2.2-9.2, p < .0001). CONCLUSIONS: Acellular mucin (M1a disease) after CRS/HIPEC for appendiceal neoplasm is associated with longer OS and RFS compared to M1b, G1 disease. Current AJCC staging does not accurately reflect the differing outcomes of these two patient populations. The presence of acellular mucin in the peritoneal cavity should not be perceived as a metastatic equivalent.

Neutropenic Enterocolitis: Clinical Features and Outcomes.

BACKGROUND: Patients undergoing chemotherapy are at risk for mucosal injury and neutropenia, which facilitate colonic mucosal invasion by the bowel flora and subsequent neutropenic enterocolitis, which has a poor prognosis. OBJECTIVE: This study aimed to assess the clinical features and outcomes of neutropenic enterocolitis in patients at a comprehensive cancer center. DESIGN: This is a retrospective cohort study. SETTING: The study was conducted at the University of Texas MD Anderson Cancer Center. PATIENTS: Neutropenic enterocolitis was defined by the presence of an absolute neutrophil count <1000/mm, compatible abdominal symptoms, and either mucosal thickening on abdominal imaging or mucosal injury on colon biopsy. Patients who had been diagnosed between 2010 and 2018 were included. MAIN OUTCOMES: Complication and survival rates were analyzed using logistic regression and Cox regression analyses, respectively. RESULTS: Of the 49,244 patients who had neutropenia during the study period, 134 (2.7%) were included. The median time from neutropenia onset to neutropenic enterocolitis was 2 days (interquartile range, 1-10 days). Neutropenic enterocolitis symptoms lasted for a median of 11 days (interquartile range, 6-22 days). Most patients received antibiotics (88%) and granulocyte colony-stimulating factor (68%). Complications included sepsis (11%), colonic perforation (2%), pneumatosis intestinalis (2%), and abscess formation (2%). The risks associated with complications included immunosuppressive therapy use within 1 month before neutropenic enterocolitis onset (OR, 3.92; 95% CI, 1.04-14.76) and delayed imaging (OR, 1.10; 95% CI, 1.03-1.17). Older age, severe neutropenia, prolonged neutropenia before and after neutropenic enterocolitis diagnosis, and other concomitant systemic infections were associated with lower survival rates. LIMITATIONS: The performance of this study at a single center and its retrospective nature are limitations of the study. CONCLUSION: The prompt diagnosis and management of neutropenic enterocolitis are critical to prevent complications. The use of granulocyte colony-stimulating factor can be beneficial to shorten the duration of neutropenia. See Video Abstract at http://links.lww.com/DCR/B116. ENTEROCOLITIS NEUTROPÉNICA: CARACTERÍSTICAS CLÍNICAS Y RESULTADOS: Los pacientes sometidos a quimioterapia, están en riesgo de lesión de la mucosa y neutropenia, lo que facilita la invasión de la mucosa colónica por la flora intestinal y la subsecuente enterocolitis neutropénica, con un mal pronóstico.Evaluar las características clínicas y los resultados de la enterocolitis neutropénica de pacientes en un centro integral de cáncer.Estudio de cohorte retrospectivo.El estudio se realizó en el MD Anderson Cancer Center de la Universidad de Texas.Se definió la enterocolitis neutropénica, como la presencia de un recuento absoluto de neutrófilos <1000 / mm3, con síntomas compatibles abdominales y engrosamiento de la mucosa en imagen abdominal o lesión de la mucosa en biopsia de colon. Se incluyeron pacientes diagnosticados entre 2010 y 2018.Se analizaron las tasas de complicaciones y supervivencia mediante análisis de regresión logística y regresión de Cox.De 49,244 pacientes que tuvieron neutropenia durante el período de estudio, 134 (2.7%) fueron incluidos. La media del tiempo desde el inicio de la neutropenia hasta la enterocolitis neutropénica, fue de 2 días (RIC, 1-10 días). Los síntomas de enterocolitis neutropénica duraron una media de 11 días (RIC, 6-22 días). La mayoría de los pacientes recibieron antibióticos (88%) y factor estimulante de colonias de granulocitos (68%). Las complicaciones incluyeron sepsis (11%), perforación colónica (2%), neumatosis intestinal (2%) y formación de abscesos (2%). Los riesgos asociados con las complicaciones incluyeron, uso de terapia inmunosupresora dentro de 1 mes antes del inicio de la enterocolitis neutropénica (razón de probabilidades 3.92; intervalo de confianza del 95% 1.04-14.76) y demora en la obtención de imágenes (razón de probabilidades 1.10; intervalo de confianza del 95% 1.03-1.17), edad avanzada, neutropenia grave, neutropenia prolongada antes y después del diagnóstico de enterocolitis neutropénica y de otras infecciones sistémicas concomitantes, se asociaron con bajas tasas de supervivencia.Centro único y estudio retrospectivo.El rápidodiagnóstico y manejo de la enterocolitis neutropénica, es crítico para prevenir complicaciones. El uso del factor estimulante de colonias de granulocitos puede ser beneficioso para acortar la duración de la neutropenia. Consulte Video Resumen en http://links.lww.com/DCR/B116.

Diagnostic value of biopsy sampling in predicting histology in patients with diffuse malignant pleural mesothelioma.

BACKGROUND: The classification of diffuse malignant mesothelioma into epithelioid, biphasic, and sarcomatoid types is based on histologic patterns. The diagnosis is made on biopsies, and because of intratumoral heterogeneity, they may not be representative of the entire tumor. The number and volume of biopsies needed to reach diagnostic accuracy in diffuse malignant mesothelioma and their prognostic value remain unclear. METHODS: This study examined 759 consecutive patients with pleural diffuse malignant mesothelioma treated by pleurectomy/decortication or extrapleural pneumonectomy for the presence of epithelioid and/or sarcomatoid histology and classified both the presurgery biopsies (core-needle or thoracoscopic) and surgical resection specimens. The number and volume of biopsies were correlated with pre- and postsurgery histologies and overall survival. RESULTS: Diffuse malignant mesothelioma was classified as epithelioid (76%), biphasic (18%), sarcomatoid (5%), or indeterminate (1%) in biopsies and as epithelioid (64%), biphasic (32%), and sarcomatoid (4%) in surgical resection specimens (overall concordance, 80.6%). The positive likelihood ratios were 2.4, 13.6, and 90.1 for biopsies with epithelioid, biphasic, and sarcomatoid histologies, respectively. Concordant histologies between biopsies and resections were associated with a higher number of biopsies (median tissue blocks for concordant histologies vs discordant histologies, 3 vs 2; P < .002) but were less associated with a higher volume (median, 1.2 vs 1.1 cm3 ; P = .06). In a multivariate analysis, overall survival was independently predicted by histology in the resection specimen (P < .0001) but not in the biopsy (P = .09). CONCLUSIONS: In contrast to epithelioid histology, sarcomatoid histology in biopsies is highly accurate. Despite intratumoral heterogeneity, the accuracy of histologic classification increases with the number of tissue blocks examined, emphasizing the diagnostic value of extensive sampling by presurgery biopsies.

Lynch Syndrome: Genomics Update and Imaging Review.

Lynch syndrome is the most common hereditary cancer syndrome, the most common cause of heritable colorectal cancer, and the only known heritable cause of endometrial cancer. Other cancers associated with Lynch syndrome include cancers of the ovary, stomach, urothelial tract, and small bowel, and less frequently, cancers of the brain, biliary tract, pancreas, and prostate. The oncogenic tendency of Lynch syndrome stems from a set of genomic alterations of mismatch repair proteins. Defunct mismatch repair proteins cause unusually high instability of regions of the genome called microsatellites. Over time, the accumulation of mutations in microsatellites and elsewhere in the genome can affect the production of important cellular proteins, spurring tumorigenesis. Universal testing of colorectal tumors for microsatellite instability (MSI) is now recommended to (a) prevent cases of Lynch syndrome being missed owing to the use of clinical criteria alone, (b) reduce morbidity and mortality among the relatives of affected individuals, and (c) guide management decisions. Organ-specific cancer risks and associated screening paradigms vary according to the sex of the affected individual and the type of germline DNA alteration causing the MSI. Furthermore, Lynch syndrome-associated cancers have different pathologic, radiologic, and clinical features compared with their sporadic counterparts. Most notably, Lynch syndrome-associated tumors tend to be more indolent than non-Lynch syndrome-associated neoplasms and thus may respond differently to traditional chemotherapy regimens. The high MSI in cases of colorectal cancer reflects a difference in the biologic features of the tumor, possibly with a unique susceptibility to immunotherapy. ©RSNA, 2018.

Nivolumab for previously treated unresectable metastatic anal cancer (NCI9673): a multicentre, single-arm, phase 2 study.

BACKGROUND: Squamous cell carcinoma of the anal canal (SCCA) is a rare malignancy associated with infection by human papillomavirus (HPV). No consensus treatment approach exists for the treatment of metastatic disease. Because intratumoral HPV oncoproteins upregulate immune checkpoint proteins such as PD-1 to evade immune-mediated cytotoxicity, we did a trial of the anti-PD-1 antibody nivolumab for patients with metastatic SCCA. METHODS: We did this single-arm, multicentre, phase 2 trial at ten academic centres in the USA. We enrolled patients with treatment-refractory metastatic SCCA, who were given nivolumab every 2 weeks (3 mg/kg). The primary endpoint was response according to Response Evaluation Criteria in Solid Tumors, version 1.1, in the intention-to-treat population. At the time of data cutoff, the study was ongoing, with patients continuing to receive treatment. The study is registered with ClinicalTrials.gov, number NCT02314169. RESULTS: We screened 39 patients, of whom 37 were enrolled and received at least one dose of nivolumab. Among the 37 patients, nine (24% [95% CI 15-33]) had responses. There were two complete responses and seven partial responses. Grade 3 adverse events were anaemia (n=2), fatigue (n=1), rash (n=1), and hypothyroidism (n=1). No serious adverse events were reported. INTERPRETATION: To our knowledge, this is the first completed phase 2 trial of immunotherapy for SCCA. Nivolumab is well tolerated and effective as a monotherapy for patients with metastatic SCCA. Immune checkpoint blockade appears to be a promising approach for patients with this orphan disease. FUNDING: National Cancer Institute/Cancer Therapy Evaluation Program, the HPV and Anal Cancer Foundation, the E B Anal Cancer Fund, The University of Texas MD Anderson Moon Shots Program, and an anonymous philanthropic donor.

Utility of Appendiceal Calcifications Detected on Computed Tomography as a Predictor for an Underlying Appendiceal Epithelial Neoplasm.

BACKGROUND: Mucinous appendiceal neoplasms can contain radiopaque calcifications. Whether appendiceal radiographic calcifications indicate the presence of an appendiceal epithelial neoplasm is unknown. This study aimed to determine whether appendiceal calcifications detected by computed tomography (CT) correlate with the presence of appendiceal epithelial neoplasms. METHODS: From prospective appendiceal and pathology databases, 332 cases of appendiceal neoplasm and 136 cases of control appendectomy were identified, respectively. Only cases with preoperative CT scans available for review were included in the study. Images were reviewed by two abdominal radiologists. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were calculated, and the kappa statistic was used to determine agreement between the radiologists' interpretations. RESULTS: Interobserver agreement between the radiologists was substantial, with a kappa of 0.74. Appendiceal mural calcifications were identified on CT scans in 106 appendiceal neoplasm cases (32%) and in 1 control case (1%) (P = 0.0001). In the appendiceal neoplasm subgroup, the presence of radiographic calcifications was associated with mucinous histology (35% vs 17%; P = 0.006; odds ratio [OR], 0.38; 95% confidence interval [CI], 0.18-0.78) and with well-differentiated histologic grade (40% vs 24%; P = 0.002; OR, 0.47; 95% CI, 0.29-0.76). The findings showed a sensitivity of 31.9% (95% CI, 26.9-37.2%), a specificity of 99.3% (95% CI, 96-100%), a PPV of 99.1% (95% CI, 94.9-100%), and an NPV of 37.4% (95% CI, 32.4-42.6%). CONCLUSION: This case-control study showed that appendiceal mural calcifications detected on CT are associated with underlying appendiceal epithelial neoplasms and that the identification of incidental mural appendiceal calcifications may have an impact on decisions regarding surgical intervention.

Serum Tumor Markers and Outcomes in Patients With Appendiceal Adenocarcinoma.

Importance: Serum tumor markers carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), and cancer antigen 125 (CA125) have been useful in the management of gastrointestinal and gynecological cancers; however, there is limited information regarding their utility in patients with appendiceal adenocarcinoma. Objective: To assess the association of serum tumor markers (CEA, CA19-9, and CA125) with clinical outcomes and pathologic and molecular features in patients with appendiceal adenocarcinoma. Design, Setting, and Participants: This is a retrospective cohort study at a single tertiary care comprehensive cancer center. The median (IQR) follow-up time was 52 (21-101) months. Software was used to query the MD Anderson internal patient database to identify patients with a diagnosis of appendiceal adenocarcinoma and at least 1 tumor marker measured at MD Anderson between March 2016 and May 2023. Data were analyzed from January to December 2023. Main Outcomes and Measures: Association of serum tumor markers with survival in patients with appendiceal adenocarcinoma. Cox proportional hazards regression analyses were also performed to assess associations between clinical factors (serum tumor marker levels, demographics, and patient and disease characteristics) and patient outcomes (overall survival). Results: A total of 1338 patients with appendiceal adenocarcinoma were included, with a median (range) age at diagnosis of 56.5 (22.3-89.6) years. The majority of the patients had metastatic disease (1080 patients [80.7%]). CEA was elevated in 742 of the patients tested (56%), while CA19-9 and CA125 were elevated in 381 patients (34%) and 312 patients (27%), respectively. Individually, elevation of CEA, CA19-9, or CA125 were associated with worse 5-year survival; elevated vs normal was 81% vs 95% for CEA (hazard ratio [HR], 4.0; 95% CI, 2.9-5.6), 84% vs 92% for CA19-9 (HR, 2.2; 95% CI, 1.4-3.4), and 69% vs 93% for CA125 (HR, 4.6; 95% CI, 2.7-7.8) (P < .001 for all). Quantitative evaluation of tumor markers was associated with outcomes. Patients with highly elevated (top 10th percentile) CEA, CA19-9, or CA125 had markedly worse survival, with 5-year survival rates of 59% for CEA (HR, 9.8; 95% CI, 5.3-18.0), 64% for CA19-9 (HR, 6.0; 95% CI, 3.0-11.7), and 57% for CA125 (HR, 7.6; 95% CI, 3.5-16.5) (P < .001 for all). Although metastatic tumors had higher levels of all tumor markers, when restricting survival analysis to 1080 patients with metastatic disease, elevated CEA, CA19-9, or CA125 were all still associated worse survival (HR for CEA, 3.4; 95% CI, 2.5-4.8; P < .001; HR for CA19-9, 1.8; 95% CI, 1.2-2.7; P = .002; and HR for CA125, 3.9; 95% CI, 2.4-6.4; P < .001). Interestingly, tumor grade was not associated with CEA or CA19-9 level, while CA-125 was slightly higher in high-grade tumors relative to low-grade tumors (mean value, 18.3 vs 15.0; difference, 3.3; 95% CI, 0.9-3.7; P < .001). Multivariable analysis identified an incremental increase in the risk of death with an increase in the number of elevated tumor markers, with an 11-fold increased risk of death in patients with all 3 tumor markers elevated relative to those with none elevated. Somatic mutations in KRAS and GNAS were associated with significantly higher levels of CEA and CA19-9. Conclusions and Relevance: In this retrospective study of serum tumor markers in patients with appendiceal adenocarcinoma, CEA, CA19-9, and CA125 were associated with overall survival in appendiceal adenocarcinoma. Given their value, all 3 biomarkers should be included in the initial workup of patients with a diagnosis of appendiceal adenocarcinoma.

Interobserver Variability and Challenges in Intraoperative Frozen Section Evaluation of Pancreatic Margins in Pancreatectomy Specimens.

OBJECTIVE: Frozen-section evaluation of the pancreatic margin is challenging. We aimed to determine interobserver variability among gastrointestinal pathologists for the assessment of frozen sections of pancreatic margins with marked chronic pancreatitis and to determine the challenging histological features in discrepant cases. METHODS: We identified 45 patients who underwent pancreas resection for pancreatic ductal adenocarcinoma and showed marked chronic pancreatitis at pancreatic margin. Deidentified first levels of frozen-sections of the pancreatic margins from all cases were independently reviewed by 5 experienced gastrointestinal pathologists for the presence of carcinoma and/or high-grade dysplasia. RESULTS: Interobserver agreement among pathologists was calculated as kappa coefficients ([Formula: see text]). A consensus diagnosis for discordant cases was obtained after group review and discussion. Interobserver agreement for adenocarcinoma diagnosis was 87%, and there was "substantial agreement" (Fleiss [Formula: see text]=0.78, P<0.01) and "almost perfect agreement" (Brennan-Prediger [Formula: see text]=0.86, P<0.01). Using the final diagnosis based on frozen and permanent sections as the gold standard and the concordant read of at least 3 of 5 pathologists for comparison, the diagnosis of adenocarcinoma was made in frozen-sections of pancreas margins, with accuracy 98%, sensitivity 83%, specificity 100%, negative predictive value 97%, positive predictive value 100%, false negative rate 9%, and false positive rate 0%. CONCLUSIONS: We showed excellent interobserver agreement among gastrointestinal pathologists for diagnosis of adenocarcinoma on frozen sections of pancreatic margins with marked chronic pancreatitis. Missed adenocarcinoma at the margin was mainly caused by freezing or cautery artifacts or by overlooking a tiny focus of perineural invasion in a background of marked chronic pancreatitis. The evaluation of deeper levels led to perfect agreement.

Neoadjuvant Pembrolizumab in Localized Microsatellite Instability High/Deficient Mismatch Repair Solid Tumors.

PURPOSE: Pembrolizumab significantly improves clinical outcomes in advanced/metastatic microsatellite instability high (MSI-H)/deficient mismatch repair (dMMR) solid tumors but is not well studied in the neoadjuvant space. METHODS: This is a phase II open-label, single-center trial of localized unresectable or high-risk resectable MSI-H/dMMR tumors. Treatment is pembrolizumab 200 mg once every 3 weeks for 6 months followed by surgical resection with an option to continue therapy for 1 year followed by observation. To continue on study, patients are required to have radiographic or clinical benefit. The coprimary end points are safety and pathologic complete response. Key secondary end points are response rate and organ-sparing at one year for patients who declined surgery. Exploratory analyses include interrogation of the tumor immune microenvironment using imaging mass cytometry. RESULTS: A total of 35 patients were enrolled, including 27 patients with colorectal cancer and eight patients with noncolorectal cancer. Among 33 evaluable patients, best overall response rate was 82%. Among 17 (49%) patients who underwent surgery, the pathologic complete response rate was 65%. Ten patients elected to receive one year of pembrolizumab followed by surveillance without surgical resection (median follow-up of 23 weeks [range, 0-54 weeks]). An additional eight did not undergo surgical resection and received less than 1 year of pembrolizumab. During the study course of the trial and subsequent follow-up, progression events were seen in six patients (four of whom underwent salvage surgery). There were no new safety signals. Spatial immune profiling with imaging mass cytometry noted a significantly closer proximity between granulocytic cells and cytotoxic T cells in patients with progressive events compared with those without progression. CONCLUSION: Neoadjuvant pembrolizumab in dMMR/MSI-H cancers is safe and resulted in high rates of pathologic, radiographic, and endoscopic response, which has implications for organ-sparing strategies.

Differential Spatial Gene and Protein Expression Associated with Recurrence Following Chemoradiation for Localized Anal Squamous Cell Cancer.

The identification of transcriptomic and protein biomarkers prognosticating recurrence risk after chemoradiation of localized squamous cell carcinoma of the anus (SCCA) has been limited by a lack of available fresh tissue at initial presentation. We analyzed archival FFPE SCCA specimens from pretreatment biopsies prior to chemoradiation for protein and RNA biomarkers from patients with localized SCCA who recurred (N = 23) and who did not recur (N = 25). Tumor cells and the tumor microenvironment (TME) were analyzed separately to identify biomarkers with significantly different expression between the recurrent and non-recurrent groups. Recurrent patients had higher mean protein expression of FoxP3, MAPK-activation markers (BRAF, p38-MAPK) and PI3K/Akt activation (phospho-Akt) within the tumor regions. The TME was characterized by the higher protein expression of immune checkpoint biomarkers such as PD-1, OX40L and LAG3. For patients with recurrent SCCA, the higher mean protein expression of fibronectin was observed in the tumor and TME compartments. No significant differences in RNA expression were observed. The higher baseline expression of immune checkpoint biomarkers, together with markers of MAPK and PI3K/Akt signaling, are associated with recurrence following chemoradiation for patients with localized SCCA. These data provide a rationale towards the application of immune-based therapeutic strategies to improve curative-intent outcomes beyond conventional therapies for patients with SCCA.

Efficacy of Systemic Chemotherapy in Patients With Low-grade Mucinous Appendiceal Adenocarcinoma: A Randomized Crossover Trial.

Importance: Appendiceal adenocarcinoma is a rare tumor, and given the inherent difficulties in performing prospective trials in such a rare disease, there are currently minimal high-quality data to guide treatment decisions, highlighting the need for more preclinical and clinical investigation for this disease. Objective: To prospectively evaluate the effectiveness of fluoropyrimidine-based systemic chemotherapy in patients with inoperable low-grade mucinous appendiceal adenocarcinoma. Design, Setting, and Participants: This open-label randomized crossover trial recruited patients at a single tertiary care comprehensive cancer center from September 2013 to January 2021. The data collection cutoff was May 2022. Enrollment of up to 30 patients was planned. Eligible patients had histological evidence of a metastatic low-grade mucinous appendiceal adenocarcinoma, with radiographic imaging demonstrating the presence of mucinous peritoneal carcinomatosis and were not considered candidates for complete cytoreductive surgery. Key exclusion criteria were concurrent or recent investigational therapy, evidence of bowel obstruction, and use of total parenteral nutrition. Data were analyzed from November 2021 to May 2022. Interventions: Patients were randomized to either 6 months observation followed by 6 months of chemotherapy, or initial chemotherapy followed by observation. Main Outcomes and Measures: The primary end point was the percentage difference in tumor growth in treatment and observation groups. Key secondary end points included patient-reported outcomes in the chemotherapy and observation periods, objective response rate, rate of bowel complications, and differences in overall survival (OS). Results: A total of 24 patients were enrolled, with median (range) age of 63 (38 to 82) years, and equal proportion of men and women (eg, 12 men [50%]); all patients had ECOG performance status of 0 or 1. A total of 11 patients were randomized to receive chemotherapy first, and 13 patients were randomized to receive observation first. Most patients (15 patients [63%]) were treated with either fluorouracil or capecitabine as single agent; 3 patients (13%) received doublet chemotherapy (leucovorin calcium [folinic acid], fluorouracil, and oxaliplatin or folinic acid, fluorouracil, and irinotecan hydrochloride), and bevacizumab was added to cytotoxic chemotherapy for 5 patients (21%). Fifteen patients were available to evaluate the primary end point of difference in tumor growth during treatment and observation periods. Tumor growth while receiving chemotherapy increased 8.4% (95% CI, 1.5% to 15.3%) from baseline but was not significantly different than tumor growth during observation (4.0%; 95% CI, -0.1% to 8.0%; P = .26). Of 18 patients who received any chemotherapy, none had an objective response (14 patients [77.8%] had stable disease; 4 patients [22.2%] had progressive disease). Median (range) OS was 53.2 (8.1 to 95.5) months, and there was no significant difference in OS between the observation-first group (76.0 [8.6 to 95.5] months) and the treatment-first group (53.2 [8.1 to 64.1] months; hazard ratio, 0.64; 95% CI, 0.16-2.55; P = .48). Patient-reported quality-of-life metrics identified that during treatment, patients experienced significantly worse fatigue (mean [SD] score, 18.5 [18.6] vs 28.9 [21.3]; P = .02), peripheral neuropathy (mean [SD] score, 6.67 [12.28] vs 38.89 [34.88]; P = .01), and financial difficulty (mean [SD] score, 8.9 [15.2] vs 28.9 [33.0]; P = .001) compared with during observation. Conclusions and Relevance: In this prospective randomized crossover trial of systemic chemotherapy in patients with low-grade mucinous appendiceal adenocarcinoma, patients did not derive clinical benefit from fluorouracil-based chemotherapy, given there were no objective responses, no difference in OS when treatment was delayed 6 months, and no difference in the rate of tumor growth while receiving chemotherapy. Trial Registration: ClinicalTrials.gov Identifier: NCT01946854.

The Clinical Significance of CEA, CA19-9, and CA125 in Management of Appendiceal Adenocarcinoma.

Importance: Serum tumor markers CEA, CA19-9, & CA125 have been useful in the management of gastrointestinal and gynecological cancers, however there is limited information regarding their utility in patients with appendiceal adenocarcinoma. Objective: Assessing the association of serum tumor markers (CEA, CA19-9, and CA125) with clinical outcomes, pathologic, and molecular features in patients with appendiceal adenocarcinoma. Design: This is a retrospective study with results reported in 2023. The median follow-up time was 43 months. Setting: Single tertiary care comprehensive cancer center. Participants: Under an approved Institutional Review Board protocol, the Palantir Foundry software system was used to query the MD Anderson internal patient database to identify patients with a diagnosis of appendiceal adenocarcinoma and at least one tumor marker measured at MD Anderson between 2016 and 2023. Results: A total of 1,338 patients with appendiceal adenocarcinoma were included, with a median age of 56.5 years. The majority of the patients had metastatic disease (80.7%). CEA was elevated in more than half of the patients tested (56%), while CA19-9 and CA125 were elevated in 34% and 27%, respectively. Individually, elevation of CEA, CA19-9, or CA125 were associated with worse 5-year survival; 82% vs 95%, 84% vs 92%, and 69% vs 93% elevated vs normal for CEA, CA19-9, and CA125 respectively (all p<0.0001). Quantitative evaluation of tumor markers increased prognostic ability. Patients with highly elevated (top 10th percentile) CEA, CA19-9 or CA125 had markedly worse survival with 5-year survival rates of 59%, 64%, and 57%, respectively (HR vs. normal : 9.8, 6.0, 7.6, all p<0.0001). Although metastatic tumors had higher levels of all tumor markers, when restricting survival analysis to 1080 patients with metastatic disease elevated CEA, CA19-9 or CA125 were all still associated worse survival (HR vs. normal : 3.4, 1.8, 3.9, p<0.0001 for CEA and CA125, p=0.0019 for CA19-9). Interestingly tumor grade was not associated with CEA or CA19-9 level, while CA-125 was slightly higher in high relative to low-grade tumors (18.3 vs. 15.0, p=0.0009). Multivariable analysis identified an incremental increase in the risk of death with an increase in the number of elevated tumor markers, with a 11-fold increased risk of death in patients with all three tumor markers elevated relative to those with none elevated. Mutation in KRAS and GNAS were associated with significantly higher levels of CEA and CA19-9. Conclusions: These findings demonstrate the utility of measuring CEA, CA19-9, and CA125 in the management of appendiceal adenocarcinoma. Given their prognostic value, all three biomarkers should be included in the initial workup of patients diagnosed with appendiceal adenocarcinoma.

Intestinal toxicity to CTLA-4 blockade driven by IL-6 and myeloid infiltration.

Immune checkpoint blockade (ICB) has revolutionized cancer treatment, yet quality of life and continuation of therapy can be constrained by immune-related adverse events (irAEs). Limited understanding of irAE mechanisms hampers development of approaches to mitigate their damage. To address this, we examined whether mice gained sensitivity to anti-CTLA-4 (αCTLA-4)-mediated toxicity upon disruption of gut homeostatic immunity. We found αCTLA-4 drove increased inflammation and colonic tissue damage in mice with genetic predisposition to intestinal inflammation, acute gastrointestinal infection, transplantation with a dysbiotic fecal microbiome, or dextran sodium sulfate administration. We identified an immune signature of αCTLA-4-mediated irAEs, including colonic neutrophil accumulation and systemic interleukin-6 (IL-6) release. IL-6 blockade combined with antibiotic treatment reduced intestinal damage and improved αCTLA-4 therapeutic efficacy in inflammation-prone mice. Intestinal immune signatures were validated in biopsies from patients with ICB colitis. Our work provides new preclinical models of αCTLA-4 intestinal irAEs, mechanistic insights into irAE development, and potential approaches to enhance ICB efficacy while mitigating irAEs.

Interleukin-6 blockade abrogates immunotherapy toxicity and promotes tumor immunity.

Immune checkpoint blockade (ICB) therapy frequently induces immune-related adverse events. To elucidate the underlying immunobiology, we performed a deep immune analysis of intestinal, colitis, and tumor tissue from ICB-treated patients with parallel studies in preclinical models. Expression of interleukin-6 (IL-6), neutrophil, and chemotactic markers was higher in colitis than in normal intestinal tissue; T helper 17 (Th17) cells were more prevalent in immune-related enterocolitis (irEC) than T helper 1 (Th1). Anti-cytotoxic T-lymphocyte-associated antigen 4 (anti-CTLA-4) induced stronger Th17 memory in colitis than anti-program death 1 (anti-PD-1). In murine models, IL-6 blockade associated with improved tumor control and a higher density of CD4+/CD8+ effector T cells, with reduced Th17, macrophages, and myeloid cells. In an experimental autoimmune encephalomyelitis (EAE) model with tumors, combined IL-6 blockade and ICB enhanced tumor rejection while simultaneously mitigating EAE symptoms versus ICB alone. IL-6 blockade with ICB could de-couple autoimmunity from antitumor immunity.

Oncogenic KRAS Requires Complete Loss of BAP1 Function for Development of Murine Intrahepatic Cholangiocarcinoma.

Intrahepatic cholangiocarcinoma (ICC) is a primary biliary malignancy that harbors a dismal prognosis. Oncogenic mutations of KRAS and loss-of-function mutations of BRCA1-associated protein 1 (BAP1) have been identified as recurrent somatic alterations in ICC. However, an autochthonous genetically engineered mouse model of ICC that genocopies the co-occurrence of these mutations has never been developed. By crossing Albumin-Cre mice bearing conditional alleles of mutant Kras and/or floxed Bap1, Cre-mediated recombination within the liver was induced. Mice with hepatic expression of mutant KrasG12D alone (KA), bi-allelic loss of hepatic Bap1 (BhomoA), and heterozygous loss of Bap1 in conjunction with mutant KrasG12D expression (BhetKA) developed primary hepatocellular carcinoma (HCC), but no discernible ICC. In contrast, mice with homozygous loss of Bap1 in conjunction with mutant KrasG12D expression (BhomoKA) developed discrete foci of HCC and ICC. Further, the median survival of BhomoKA mice was significantly shorter at 24 weeks when compared to the median survival of ≥40 weeks in BhetKA mice and approximately 50 weeks in BhomoA and KA mice (p < 0.001). Microarray analysis performed on liver tissue from KA and BhomoKA mice identified differentially expressed genes in the setting of BAP1 loss and suggests that deregulation of ferroptosis might be one mechanism by which loss of BAP1 cooperates with oncogenic Ras in hepato-biliary carcinogenesis. Our autochthonous model provides an in vivo platform to further study this lethal class of neoplasm.

Pathological Tumor Response Following Immune Checkpoint Blockade for Deficient Mismatch Repair Advanced Colorectal Cancer.

Immune checkpoint inhibition (CPI) for metastatic colorectal cancer (mCRC) with deficient mismatch repair (dMMR) demonstrates high clinical activity that appears durable, but the impact of CPI on pathological tumor response is unknown. In this retrospective analysis, our objective was to assess pathological response and clinical outcomes in dMMR mCRC patients treated with CPI prior to surgical resection of primary and/or metastatic tumor. Among 121 advanced dMMR mCRC patients treated with CPI at 2 institutions between November 2016 and December 2018, 14 underwent surgery. Pathologic complete response was noted in the resected specimens of 13 patients despite the presence of residual tumor on preoperative imaging in 12 of those patients. With median follow-up of 9 months, no patients have had disease relapse or progression. For this small retrospective study, the data suggest that residual radiographic tumor may not require systematic resection following response to anti-PD1-based therapy. However, larger prospective studies are warranted.