Untreated Cancers Research Articles

Cancer new treatment series: Comparison immune changes of HCC by scRNA-Seq following HELC treatment one case study

Immunotherapy has emerged as a novel treatment strategy for many types of cancers, among them, liver cancer. The major advances and achievements in recent years is the use of programmed death-1 (PD-1) blockers for cancer treatment. Since patients’ immune systems are already weak following concurrent surgery plus chemo or radiotherapy, it is necessary to restore and awake their immune cells to maximize the effect for immune therapy. Methods: Liver cancers were treated twice with hapten enhanced local chemotherapy (HELC) like tumor lysates vaccine and following PD-1. Single-cell RNA sequencing (scRNA-seq) was used to analyze the changes of immune responses prior and after treatments. Results: We observed upregulation of cytotoxicity-related genes of CD8 effector T cells and NK cells in untreated tumor; Both Bmem and Naive B cells in untreated tumor showed a significant increase in MHC II signaling pathway-related genes, while MHC I-related genes was upregulated in plasma cells. Significant tumor size shrinkage was observed in both treated and untreated tumors following the HELC+PD-1 therapy. Conclusions: This study provides new biological insights into the abscopal effect at the single-cell level related to the composition of T and B cells in untreated liver cancers before and after major primary tumors treated by HELC. Our data showed that intra-tumor HELC can kill tumor cells and induced immune activity, which is likely vital in modifying tumor associate antigens (TAAs) into neo TAAs. It induces immune response just like vaccine can wake up immune cells and therefore increasing the efficacy of PD1 therapy.

Mapping extrachromosomal DNA amplifications during cancer progression.

To understand the role of extrachromosomal DNA (ecDNA) amplifications in cancer progression, we detected and classified focal amplifications in 8,060 newly diagnosed primary cancers, untreated metastases and heavily pretreated tumors. The ecDNAs were detected at significantly higher frequency in untreated metastatic and pretreated tumors compared to newly diagnosed cancers. Tumors from chemotherapy-pretreated patients showed significantly higher ecDNA frequency compared to untreated cancers. In particular, tubulin inhibition associated with ecDNA increases, suggesting a role for ecDNA in treatment response. In longitudinally matched tumor samples, ecDNAs were more likely to be retained compared to chromosomal amplifications. EcDNAs shared between time points, and ecDNAs in advanced cancers were more likely to harbor localized hypermutation events compared to private ecDNAs and ecDNAs in newly diagnosed tumors. Relatively high variant allele fractions of ecDNA localized hypermutations implicated early ecDNA mutagenesis. Our findings nominate ecDNAs to provide tumors with competitive advantages during cancer progression and metastasis.

The role of neoadjuvant clinical trials in patients with newly diagnosed glioblastoma.

e14022 Background: Novel cytotoxic drugs are commonly first studied in patients with solid tumors who have recurrent disease. If high response rates and durable remissions are observed, further studies are conducted in previously untreated cancers where the novel agent can be combined with radiation or administered as neoadjuvant therapy (NAT) to reduce tumor size before surgery or radiation and to limit systemic dissemination. While NAT can provide critical information on response rates and survival in previously untreated patients, it can add toxicities and delay the administration of standard therapies. Neoadjuvant chemotherapy is now standard-of-care in many systemic cancers but is rarely considered in patients with glioblastoma (GBM). This literature review was conducted to describe factors leading to NAT playing an increasingly important role in systemic cancers and a diminishing role in patients with GBM. Methods: Prospective trials published between 1980 and 2023 where patients with newly diagnosed systemic cancers and GBM received NAT prior to radiation were identified in PubMed. Results: During these 43 years, over 5,000 NAT trials in patients with systemic cancers were published. As a result of these studies, NAT is now considered standard therapy for 28 different cancers. In contrast, during the same years only 51 prospective studies were reported evaluating the efficacy of NAT in newly diagnosed GBM. These clinical trials accrued a total of 2,047 patients and evaluated the efficacy of nitrosoureas, temozolomide, platinum-based agents, and targeted therapies. These studies peaked before 2005, when combining temozolomide and radiation was shown to improve survival, and declined thereafter. NAT temozolomide was studied in 12 trials (641 patients) resulting in a median response rate of 35% (range 8.7-51%) and a median overall survival of 12.5 (range 6-22) months. NAT trials in patients with GBM were not associated with unexpected toxicities, major reductions in survival, or poor patient accrual. Conclusions: As in other solid tumors, NAT in patients with GBM is relatively safe and feasible. Enthusiasm for this approach has been limited by the paucity of active agents in recurrent glioblastoma that could be subsequently evaluated in newly diagnosed patients. However, the neoadjuvant setting is ideally suited to rapidly screening novel cytotoxic agents for efficacy as it allows: 1) radiographic response rates in previously untreated patients to be the primary endpoint, 2) small sample sizes, and 3) efficacy results in 2-3 months when patients are transitioned to standard care. Given the well documented safety and feasibility history of using NAT in patients with solid tumors and GBM, this approach has the ability to rapidly identify potentially active, novel cytotoxic agents, especially in patients with MGMT unmethylated, IDH wildtype GBM who are unlikely to benefit from temozolomide.

Abstract PO5-01-09: Exploring cellular heterogeneity of localised breast cancers

Abstract Breast cancer is a heterogeneous disease at multiple levels, ranging from subtype differences between patients (inter-patient heterogeneity) to the diverse composition of malignant cells, heterogeneity of hormone receptor (HR) expression and cellular makeup within single breast cancer samples (intra-tumour heterogeneity). Despite an increase in the number of effective therapies available, many patients will experience an incomplete treatment response and subsequent relapse. These adverse treatment outcomes may be attributed to the often overlooked but critical factor of cellular heterogeneity. In order to gain deeper insights into intra-tumour heterogeneity, we have applied single-cell technologies on a cohort comprising 250 primary, untreated breast cancers. We have optimized methods for tissue cryopreservation, eliminating the need for fresh sample processing, and multiplex tissue profiling. Together, these are cost-efficient processes that allow for improved handling of small tissue sizes, such as biopsies, and reduce batch effect. To ensure accurate and reliable data processing, we have developed a scalable computational workflow that includes benchmarked methods for sample SNP-demultiplexing, doublet detection, high-resolution cell annotation and cellular integration. Finally, we are extending our existing methods1 to study the cellular heterogeneity of breast cancers. Our method, scSubtyper, explores the phenotypic differences between malignant cells within tumours, by comparing each single cell to distinct features associated with different molecular subtypes and assigning each cell to one of these subtypes. Our previous study1 and preliminary results of this project revealed that over 90% of the samples exhibit a mix of malignant cells of different subtypes, and 50% of samples contain cells that have characteristics of all subtypes, demonstrating cellular heterogeneity exists not only exists between malignant cells, but also within malignant cells of a tumour. Our second approach, known as ecotyping, assesses patterns of cell type frequencies across samples and groups them based on similarity of these co-occurences. Our preliminary results have revealed the existence of 5 ecotypes that lack significant associations with samples clinical subtypes. Applying the same approach exclusively within the HR-positive samples identified 4 ecotypes characterized by distinct abundances of immune and stromal cells. This analysis revealed that ecotypes are not a simple surrogate for clinical and molecular subtypes, but their presence could drive different response to treatment. Together, our high-throughput tissue processing and computational approaches to studying intra-tumour heterogeneity are now being applied to our large, well annotated, clinical cohort. Supported by the preliminary results, we hypothesize that this study will play a vital role in optimizing breast cancer patient stratification to improve treatment management and outcome. 1. Wu, Sunny Z., et al. "A single-cell and spatially resolved atlas of human breast cancers." Nature genetics 53.9 (2021): 1334-1347. Citation Format: Beata Kiedik, Daniel Roden, Kate Harvey, Ghamdan Al-Eryani, Sunny Wu, Mun Hui, Sandra O'Toole, Elgene Lim, Charles Perou, Alex Swarbrick. Exploring cellular heterogeneity of localised breast cancers [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-01-09.

Phenotypic immune characterization of gastric and esophageal adenocarcinomas reveals profound immune suppression in esophageal tumor locations.

Tumors in the distal esophagus (EAC), gastro-esophageal junction including cardia (GEJAC), and stomach (GAC) develop in close proximity and show strong similarities on a molecular and cellular level. However, recent clinical data showed that the effectiveness of chemo-immunotherapy is limited to a subset of GEAC patients and that EACs and GEJACs generally benefit less from checkpoint inhibition compared to GACs. As the composition of the tumor immune microenvironment drives response to (immuno)therapy we here performed a detailed immune analysis of a large series of GEACs to facilitate the development of a more individualized immunomodulatory strategy. Extensive immunophenotyping was performed by 14-color flow cytometry in a prospective study to detail the immune composition of untreated gastro-esophageal cancers (n=104) using fresh tumor biopsies of 35 EACs, 38 GEJACs and 31 GACs. The immune cell composition of GEACs was characterized and correlated with clinicopathologic features such as tumor location, MSI and HER2 status. The spatial immune architecture of a subset of tumors (n=30) was evaluated using multiplex immunohistochemistry (mIHC) which allowed us to determine the tumor infiltration status of CD3+, CD8+, FoxP3+, CD163+ and Ki67+ cells. Immunophenotyping revealed that the tumor immune microenvironment of GEACs is heterogeneous and that immune suppressive cell populations such as monocytic myeloid-derived suppressor cells (mMDSC) are more abundant in EACs compared to GACs (p<0.001). In contrast, GACs indicated a proinflammatory microenvironment with elevated frequencies of proliferating (Ki67+) CD4 Th cells (p<0.001), Ki67+ CD8 T cells (p=0.002), and CD8 effector memory-T cells (p=0.024). Differences between EACs and GACs were confirmed by mIHC analyses showing lower densities of tumor- and stroma-infiltrating Ki67+ CD8 T cells in EAC compared to GAC (both p=0.021). This comprehensive immune phenotype study of a large series of untreated GEACs, identified that tumors with an esophageal tumor location have more immune suppressive features compared to tumors in the gastro-esophageal junction or stomach which might explain the location-specific responses to checkpoint inhibitors in this disease. These findings provide an important rationale for stratification according to tumor location in clinical studies and the development of location-dependent immunomodulatory treatment approaches.

Identification of unique rectal cancer-specific subtypes.

Existing colorectal cancer subtyping methods were generated without much consideration of potential differences in expression profiles between colon and rectal tissues. Moreover, locally advanced rectal cancers at resection often have received neoadjuvant chemoradiotherapy which likely has a significant impact on gene expression. We collected mRNA expression profiles for rectal and colon cancer samples (n = 2121). We observed that (i) Consensus Molecular Subtyping (CMS) had a different prognosis in treatment-naïve rectal vs. colon cancers, and (ii) that neoadjuvant chemoradiotherapy exposure produced a strong shift in CMS subtypes in rectal cancers. We therefore clustered 182 untreated rectal cancers to find rectal cancer-specific subtypes (RSSs). We identified three robust subtypes. We observed that RSS1 had better, and RSS2 had worse disease-free survival. RSS1 showed high expression of MYC target genes and low activity of angiogenesis genes. RSS2 exhibited low regulatory Tcell abundance, strong EMT and angiogenesis signalling, and high activation of TGF-β, NF-κB, and TNF-α signalling. RSS3 was characterised by the deactivation of EGFR, MAPK and WNT pathways. We conclude that RSS subtyping allows for more accurate prognosis predictions in rectal cancers than CMS subtyping and provides new insight into targetable disease pathways within these subtypes.

Abstract 3185: Glatiramer acetate enhances tumor retention and mitigates systemic toxicity of toll-like receptor 9 agonists as intratumoral immunotherapy

Abstract Pathogen-associated molecular patterns (PAMP) are conserved molecular structures produced by microorganisms that are recognized as foreign by receptors of the innate immune system. Unmethylated cytosine-guanine oligodeoxynucleotides (CpG ODNs) are a storied drug class from the PAMP family that ligates Toll-like receptor 9 (TLR9). CpG ODNs have shown promising antitumor effects in preclinical studies by inducing potent pro-inflammatory immune responses. However, there are still practical challenges that have hindered clinical success, including inefficient in vivo delivery and severe immune-related toxicities caused by systemic exposure to CpG. We previously identified that glatiramer acetate (GA), an FDA-approved, lysine-rich polypeptide, could be applied as a cationic drug delivery vector for CpG delivery proximal to the injection site while mitigating systemic release of pro-inflammatory cytokines. To dive into the mechanism and evaluate pharmacological efficacy in more pathological models that simulate colorectal carcinoma, we validated the biodistribution of GA-CpG complexes (or R4B) and explored their safety and antitumor immunity in multiple mouse colorectal carcinoma models. In the CT26 single tumor model, intratumoral R4B treatment displayed comparable antitumoral efficacy as CpG treatment. Genome-wide transcriptome analysis showed that R4B treatment elicited much more prominent immune system response pathways in both lesions and spleens. The biodistribution study proved that R4B localized and gradually released CpG around the injection site while ‘naked’ CpG diffused away from the injection site quickly. In the CT26 dual tumor-bearing model, intratumoral administration of R4B generated systemic immune efficacy that led to an abscopal effect on distant untreated cancers, comparable to treatment with CpG alone. Notably, R4B treatment accomplished these effects with greatly mitigated systemic pro-inflammatory cytokines compared to CpG alone. These data help further elucidate the noncanonical role of glatiramer acetate to serve as a nucleic acid delivery scaffold that potentiates the safety of CpG adjuvant for cancer immunotherapy. Citation Format: Huan Gong, Daniel J. Griffin, Chad E. Groer, Xiaoqing Wu, Moustafa M. Abdelaziz, Sa Wu, Liang Xu, Laird M. Forrest, Cory J. Berkland. Glatiramer acetate enhances tumor retention and mitigates systemic toxicity of toll-like receptor 9 agonists as intratumoral immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3185.

Comparation of EGFR-TKI (EGFR tyrosine kinase inhibitors) combination therapy and osimertinib for untreated EGFR-mutated advanced non-small cell lung cancers: A systematic review and network meta-analysis.

EGFR-TKI (tyrosine kinase inhibitor) monotherapy has become the first-line treatment option for patients with EGFR-mutated non-small cell lung cancer (NSCLC). Prolonging the survival time, improving the progression-free survival of front-line treatment, and delaying the occurrence of drug resistance. At present, combination therapy is being widely used. Evaluate the therapeutic effect of TKI joint and Osimertinib drug therapy for positive patients with gene positive. Articles that met the inclusion criteria were searched through electronic databases. treatment emergent adverse events were summarized, and progression-free survival (PFS) and overall survival (OS) were calculated. Appropriate networks for different outcomes were created to incorporate all the evidence. Bayesian network-based multitreatment was used to compare the efficacy and specific toxicity of all treatment regimens. Fourteen eligible studies involving 2325 patients were included. Of these, 7 studies compared EGFR-TKI plus chemotherapy with EGFR-TKI alone, and 6 studies compared EGFR-TKI plus antiangiogenic therapy with EGFR-TKI alone. One study compared Osimertinib and GP, ER, EB, and GCP were more effective than SOC in PFS analysis; however, there was no significant difference between osimertinib and the other 4 combination regimens. The cumulative probabilities of being the most efficacious treatments were (PFS, OS, treatment emergent adverse events): O (73%, 16%, 0%, 0%), GCP (14%, 64%, 10%, 16%), GP (2%, 17%,8%), and EB (3%, 3%, 8%), ER (5%, NA, 4%);GA(1%, NA, 69%). Osimertinib has the lowest side effects and provides better PFS first-line treatment in advanced EGFR-mutated NSCLC.GCP is the best regimen for OS, but its toxicity limits its application, and it may be the first choice for patients with higher survival requirements.

Abstract 5910: Prospective platform to define microbiome correlates of metastasis and therapy resistance in early onset and average onset gastrointestinal cancers

Abstract Background: The incidence of early onset (EO) gastrointestinal (GI) cancers prior to age 50 is rising, and the etiology is unknown. The gut microbiome may contribute to GI cancer pathogenesis, though how bacteria drive metastasis and treatment resistance is not known. Purpose: To define the microbiome contribution to EO-GI cancers and metastasis by analyzing longitudinal samples from previously untreated patients with GI cancers. Methods: We designed a prospective biospecimen collection platform. We selected patients with newly diagnosed, previously untreated colorectal cancer (CRC) and esophagogastric cancer (EGC). We collected stool, biopsy or surgical tissue, and peripheral blood mononuclear cells (PBMCs) at baseline prior to treatment and at each restaging scan for patients with metastatic disease. For those with locally advanced disease, we collected samples at baseline and after each treatment phase (surgery, radiation, chemotherapy). Stool samples were analyzed using shotgun sequencing. Tissue samples were banked for further analysis. Clinical data was manually curated. Relative abundances of bacteria at the species level were compared between groups. Alpha diversity was calculated using the inverse Simpson index and compared between groups using the Wilcoxon signed-rank test. Beta diversity was analyzed using the Bray-Curtis dissimilarity matrix and compared using PERMANOVA. Multivariate association between species abundance and clinical covariates was performed using MaAsLin2 R package. Results: We analyzed a total of 150 stool samples from 76 patients (colorectal n=53, esophagogastric n=23), including up to 6 samples from a single patient over time. Mean alpha diversity did not differ significantly by primary site or age at diagnosis in patients with CRC but was higher in stage IV compared with stage I disease (P=0.054). Beta diversity was significantly different between samples from patients with right- compared with left-sided CRC (P=0.005) but did not differ significantly by diagnosis age (&amp;lt;50 vs. &amp;gt; 50). Among those with EGC, mean alpha diversity was not significantly different in samples from patients with esophagus or gastroesophageal junction (proximal) tumors compared with gastric (distal) tumors and did not differ significantly by age group. Beta diversity was significantly different between patients with EGC over 50 compared with those under 50 (P=0.002). When CRC baseline samples were examined, several bacterial species were associated with age &amp;lt;50 at diagnosis, including Streptococcus anginosus group (P=0.001), Solobacterium moorei (P=0.013), and Firmicutes bacterium CAG83 (P=0.016). Conclusions/Future Directions: Microbiome composition may cluster by primary tumor site and age at diagnosis in patients with previously untreated GI cancers. Functional analysis and is ongoing and will be presented. Citation Format: Melissa A. Lumish, Asha R. Saxena, Nicholas Waters, Anqi Dai, Saskia Hartner, Teng Fei, Matthew Drescher, Jonathan Bermeo, Dorina Ismailgeci, Maggie Fox, Yelena Y. Janjigian, Luis A. Diaz, Martin R. Weiser, Jonathan Peled, Marcel van den Brink, Karuna Ganesh. Prospective platform to define microbiome correlates of metastasis and therapy resistance in early onset and average onset gastrointestinal cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5910.

TGF-β in the microenvironment induces a physiologically occurring immune-suppressive senescent state

TGF-β induces senescence in embryonic tissues. Whether TGF-β in the hypoxic tumor microenvironment (TME) induces senescence in cancer and how the ensuing senescence-associated secretory phenotype (SASP) remodels the cellular TME to influence immune checkpoint inhibitor (ICI) responses are unknown. We show that TGF-β induces a deeper senescent state under hypoxia than under normoxia; deep senescence correlates with the degree of E2F suppression and is marked by multinucleation, reduced reentry into proliferation, and a distinct 14-gene SASP. Suppressing TGF-β signaling in tumors in an immunocompetent mouse lung cancer model abrogates endogenous senescent cells and suppresses the 14-gene SASP and immune infiltration. Untreated human lung cancers with a high 14-gene SASP display immunosuppressive immune infiltration. In a lung cancer clinical trial of ICIs, elevated 14-gene SASP is associated with increased senescence, TGF-β and hypoxia signaling, and poor progression-free survival. Thus, TME-induced senescence may represent a naturally occurring state in cancer, contributing to an immune-suppressive phenotype associated with immune therapy resistance.

Effect of EGFR and ERBB2 amplifications and activating alterations on efficacy of lenvatinib in hepatocellular carcinoma.

600 Background: Hepatocellular carcinoma (HCC) is the most common primary liver cancer and is associated with a high mortality burden. Lenvatinib is an effective frontline tyrosine kinase inhibitor for HCC but is associated with primary and acquired resistance in most patients. Molecular mechanisms of resistance to lenvatinib remain unclear. Methods: We retrospectively analyzed 227 patients with HCC who underwent baseline ctDNA profiling as a component of routine clinical care, including 46 patients who had serial ctDNA analysis done at baseline and after progression to lenvatinib or ICI. Clinical data including demographics, treatment history, tumor responses, and survival outcomes were abstracted from the electronic medical record. Tumor response was categorized according to RECIST 1.1. A national registry of HCC that underwent ctDNA testing using Guardant360 was analyzed to determine the prevalence of EGFR/ERBB2 alterations in HCC. Results: Nearly a third of patients who progressed on lenvatinib demonstrated a gain in EGFR/ ERBB2 amplifications or activating mutations. No consistent trend in EGFR/ ERBB2 amplifications and alterations was found among ICI refractory HCC. Disease control rates (including complete response, partial response, and stable disease) were 20% in EGFR/ERBB2 altered HCC treated with lenvatinib, 62.5% in EGFR/ERBB2 wildtype HCC treated with lenvatinib (p = 0.05), and 58% in EGFR/ERBB2 altered HCC treated with ICIs (p = 0.09). PFS was also longer in EGFR/ERBB2 wildtype HCC treated with lenvatinib (5.9 months) and EGFR/ERBB2 altered HCC treated with ICIs (7.1 months) compared to EGFR/ERBB2 altered HCC treated with lenvatinib (2.2 months, p = 0.002). In a national cohort of 1739 patients with HCC, EGFR amplifications and activating mutations occurred in 6.5% and 1.5% of cases, respectively, and ERBB2 amplifications and activating mutations occurred in 1.9% and 0.7% of cases, respectively. Among EGFR/ERBB2 mutations, we identified recurrent gatekeeper mutations, including multiple A547T and T790M mutations, in 31% of patients. Conclusions: Our study substantiates EGFR/ERBB2 amplifications and mutations as putative drivers of lenvatinib resistance in patients with HCC and identifies the genetic mechanisms for EGFR pathway activation in refractory cancers. EGFR/ERBB2 alterations may thus represent predictive and pharmacodynamic markers of lenvatinib resistance. These findings lend support to the use of EGFR inhibitors combined with lenvatinib in previously untreated or lenvatinib refractory cancers.

Optimization of staging algorithm for newly detected prostate cancer by using PET/CT with &lt;sup&gt;68&lt;/sup&gt;Ga-PSMA: a retrospective study

INTRODUCTION: Prostate cancer (PC) is the most common malignancy in men worldwide and ranks third in mortality. Improvement of the results of staging of newly detected prostate cancer is rightfully associated with the active use in clinical practice of positron emission tomography combined with computed tomography (PET/CT) with radiotracers based on prostate-specific membrane antigen (PSMA) ligands.OBJECTIVE: The aim of the study was to determine the capabilities of PET/CT with 68Ga-PSMA in evaluating the prevalence of newly diagnosed breast cancer in comparison with traditional imaging techniques (computed tomography, magnetic resonance imaging and bone scan) and to determine the role of this technology in the choice of treatment algorithm.MATERIALS AND METHODS: 120 patients aged 46 to 74 years (median age 62.5 years) with histologically verified prostate cancer underwent PET/CT with 68Ga-PSMA in our center to assess disease prevalence. The selection criteria for the study were: prostate-specific antigen (PSA) level of 5 ng/ml and above, presence of newly detected, histologically verified prostate cancer, no treatment, suspected metastatic lesion of pelvic and skeletal lymph nodes according to CT, MRI and OSG. All patients were divided into groups according to PSA level and Gleason score. Statistics: Statistical processing of the results was performed by methods of variance statistics using Statistica 10.0, GraphPad Prism 9.3.1. Wilcoxon-Mann-Whitney and Friedman tests for ANOVA were used to determine the significance of differences between comparison groups. The chi-square test with Yates correction was used to determine the reliability of intergroup differences for nominal measures (such as the presence of previous recurrences). The level of correlation was assessed using Spearman criterion.RESULTS: PET/CT imaging analysis in addition to MRI, CT, and OSG data showed TNM staging changes in 63 of 120 patients (52.3%) due to the detection of additional foci of metastatic lesions. Change of data about local spread of tumor with increasing of TNM stage due to detection of pathological RFP accumulation in seminal vesicles in 10 of 120 patients (8.3%), without structural changes using conventional imaging methods. In 20 of 64 patients (31.3%), PET/CT revealed lesions of regional lymph nodes (N) that were not visualized by conventional imaging methods due to their small size. Metastatic lesions of distant lymph nodes (M1a) and bones (M1b) undetected by CT, MRI, and OSG were found in 27 (22.5%) and 32 (26.7%) of 120 patients, respectively. At the same time, foci of pathological accumulation of 68Ga-PSMA in the bones without structural changes on CT were detected in 7 and 32 patients (21.8%).DISCUSSION: One of the objectives of this study was to compare the diagnostic capabilities of standard diagnostic imaging techniques, in particular MRI, CT and Bone scan, with the hybrid technology of PET/CT with 68Ga-PSMA to improve the accuracy of PCa staging in order to determine treatment tactics. The results demonstrate minimal superiority of PET/CT with 68Ga-PSMA over MRI in terms of sensitivity (96% and 94%, respectively) in assessing local disease prevalence. Tumor invasion of the seminal vesicles, in most cases, was detected in patients with a Gleason score greater than 8. At the same time there was a tendency for an increase in the level of radiotracer accumulation in the tumor tissue of the seminal vesicles depending on the differentiation group of PCa. Analysis of the histological material obtained after the prostatectomy demonstrated tumorous invasion of the seminal vesicles in 26 (37.1%) out of 70 operated patients. Coincidence of histological examination results with PET/CT data was found in 22 patients, with MRI data — in 20 patients. The sensitivity, specificity, positive predictive value, and negative predictive value of PET/CT were 85%, 92%, 85%, and 92%, while the corresponding values from MRI were as follows: 77%, 88%, 77%, and 88%. Analyzing the levels of 68Ga-PSMA uptake in the tumor tissue, we found that with increasing prostate differentiation group, there was a persistent increase in radiotracer accumulation in the prostate tumor tissue. We also evaluated the interrelation of RFP accumulation with PSA level. The patients with PCa with PSA level ≥10.0 ng/ml demonstrated high accumulation of radiotracer accumulation compared to those with PSA &lt;10.0 ng/ml (p&lt;0.001).CONCLUSIONS: The use of 68Ga-PSMA PET/CT in the staging of newly diagnosed and untreated cancers provides comprehensive information on the local, regional, and distant extent of the disease, and in some cases contributes to a change in TNM stage of the disease in a single study. The use of this method before planned surgical treatment of PCa can significantly reduce the risk of early postoperative relapse, especially in patients with a Gleason score of more than 7 and a PSA level greater than 20 ng/ml.

Spectrum of EGFR mutation and its relation with high-risk predictors in thyroid cancer in Kashmiri population: 2 years prospective study at a tertiary care hospital

BackgroundEGFR mutation has not been extensively studied in thyroid cancer. This study was conducted to study spectrum of EGFR mutation in thyroid cancer in Kashmiri population for possible therapeutic purpose.MethodsIt was 2 years prospective cross-sectional study conducted at a tertiary care center in which histologically confirmed, untreated thyroid cancers were included. These specimens were subjected to EGFR mutation analysis by AS-PCR method.ResultsThere were a total 60 patients with preponderance of females [44(73%) vs 16(27%)]. Most were in the age group of less than 45 years (75%). Most of these patients were non-smokers [50(83.3%) vs 10 (17.3%)]. Papillary thyroid carcinoma (PTC) was the commonest type 48(80%), rest was follicular type (FTC) 12(20%). Well-differentiated carcinoma (WDC) was common than poorly differentiated (PDC) [41(68.4%) vs 19 (31.6%)]. Lymph node metastasis and vascular invasion were present in 32 (53.4%) and 17 (28.4%) respectively. Thirty-two (53.3%) patients were having 15 bp deletion in exon 19 of EGFR. These deletions were common in PTC than FTC, 29(60.5%) vs 3(25%) which was statistically significant (p = 0.04, CI = 0.2). The total mutational rate of T790M in EGFR tyrosine kinase domain (exon 20) was found to be only 8.4% (5 of 60). Only 4 (8.3%) of these mutations were detected in PTC and rest in FTC (1 of 12). Twenty-six (43.3%) of exon 21 were positive for L858R mutation in EGFR tyrosine kinase domain. Married persons and PDC were significant predictors of L858R mutation in EGFR tyrosine kinase domain in thyroid cancer as this was statistically significant in them with p = 0.04, 0.03 respectively.ConclusionIn our population, PTC is common in females with half of population harboring EGFR mutation and it is statistically significant in poorly differentiated carcinoma and in married individuals.It implies that EGFR may be used in thyroid cancer as a possible therapeutic agent in our set of population.

EP08.02-104 Osimertinib in Untreated EGFR-Mutant Non-small Cell Lung Cancers: Overall Survival and Budget Impact Analysis in Real-World

The observational prospective multicenter FLOWER study (NCT04965701) confirmed effectiveness and safety of osimertinib in the real-world (RW) management of untreated EGFR-mutant advanced non-small cell lung cancer (aNSCLC) patients (Lorenzi M. et al., The Oncologist, 2021, DOI:https://doi.org/10.1002/onco.13951). Herein, we report updated effectiveness data, post-progression diagnostic-therapeutic pathway and the budget impact (BI) of osimertinib on the national health system (NHS).

Genomic and transcriptomic determinants of response to neoadjuvant therapy in rectal cancer.

The incidence of rectal cancer is increasing in patients younger than 50 years. Locally advanced rectal cancer is still treated with neoadjuvant radiation, chemotherapy and surgery, but recent evidence suggests that patients with a complete response can avoid surgery permanently. To define correlates of response to neoadjuvant therapy, we analyzed genomic and transcriptomic profiles of 738 untreated rectal cancers. APC mutations were less frequent in the lower than in the middle and upper rectum, which could explain the more aggressive behavior of distal tumors. No somatic alterations had significant associations with response to neoadjuvant therapy in a treatment-agnostic manner, but KRAS mutations were associated with faster relapse in patients treated with neoadjuvant chemoradiation followed by consolidative chemotherapy. Overexpression of IGF2 and L1CAM was associated with decreased response to neoadjuvant therapy. RNA-sequencing estimates of immune infiltration identified a subset of microsatellite-stable immune hot tumors with increased response and prolonged disease-free survival.

Report on lung cancer surgery during COVID-19 pandemic at a high volume US institution.

BackgroundThe impact of COVID-19 has been felt in every field of medicine. We sought to understand how lung cancer surgery was affected at a high volume institution. We hypothesized that patients would wait longer for surgery, have more advanced tumors, and experience more complications during the COVID-19 crisis.MethodsA retrospective review was conducted, comparing pathologically confirmed non-small cell lung cancer (NSCLC) surgical cases performed in 2019 to cases performed from March to May 2020, during the height of the COVID-19 crisis. Clinical and pathologic stage, tumor size, time to surgery, follow up time, and complications were evaluated.ResultsA total of 375 cases were performed in 2019 vs. 58 cases in March to May 2020. Overall, there were no differences in the distribution of clinical stages or in the distribution of median wait times to surgery between groups (COVID-19 16.5 days vs. pre-COVID-19 17 days, P=0.54), nor were there differences when subdivided into Stage I-II and Stage III-IV. Case volume was lowest in April 2020 with 6 cases vs. 37 in April 2019, P<0.01. Tumor size was clinically larger in the COVID-19 group (median 2.1 vs. 1.9 cm, P=0.05) but not at final pathology. No differences in complications were observed between groups (COVID-19 31.0% vs. pre-COVID-19 30.9%, P=1.00). No patients from the COVID-19 group tested positive for the disease during their hospital stay or by the median 15 days to first follow-up.ConclusionsSurgical wait time, pathologic tumor size, and complications were not different among patients undergoing surgery before vs. during the pandemic. Importantly, no patients became infected as a result of their hospital stay. The significant decrease in surgical cases is concerning for untreated cancers that may progress without proper treatment.

Abstract 1963: Spatial patterns of microenvironmental biomarkers drive long-term breast cancer outcome

Abstract Determining early biomarkers of long-term survival remain a significant challenge for solid tumors. Certain spatial patterns of immune and stroma cells within tumors have been correlated with treatment response across cancer types, including breast cancer. Mechanical and physical microenvironmental signatures have emerged as drivers of cancer aggressiveness and invasiveness. This suggests that physio/mechanical structures may drive the formation of favorable immune-tumor-stroma cell patterns. In this work, we use a novel 60-marker imaging mass cytometry panel that included 16 tumor markers, 20 immune markers and 24 microenvironmental markers to resolve spatial patterns of cells, mechanical, structural, and other biomarkers within 700 clinical tumor samples (tissue microarrays from untreated primary breast cancers). Table 1 Sample distribution, patients were also treated surgically. Imaging and clinical data (eg. pathology, treatment, 10+ years survival) were integrated and analyzed to extract cell phenotypes, neighboring cells/markers and establish cell density, microenvironmental marker presence, and repeating spatial cell/marker patterns in all samples. Several markers showed significant increased expression in the survival group including CD3, CD44, CD20 for cellular markers, α-SMA, Pan-Cytokeratin, Cytokeratin 5, MMP2, LOX, and HIF1α for mechanical/microenvironmental markers. Conversely, breast cancer death samples exhibited upregulation of Na+/K+ ATPase, hCA9, and Ki67. Moreover, we identified that the co-localization of mechanical markers such as Integrin β1 and Plakoglobin is a signature of tumors with poor outcome, while the individual presence of either does not affect survival. For each of the cells/markers studied, we investigated functional relationships and identified clusters that drive survival such as Vimentin+/β-actin+ B cells, which suggests that the role of mechanics is critical to the tumor-controlling functions of immune cells. Long-term survival Cohort Survival Breast cancer death N samples 174 113 Long-term disease status Disease-free 94% 14% Local reoccurrence 4% 59% Distant reoccurrence 2% 27% Treatment No adjuvant treatment 3% 10% Adj. radiation 3% 4% Adj. chemo 0% 4% Adj. endocrine 28% 7% Adj .rad + chemo 13% 30% Adj. rad + endocrine 25% 35% Adj. chemo + endocrine 6% 4% Adj. rad + chemo + endocrine 21% 6% Citation Format: Sara Nizzero, Licheng Zhang, Yitian Xu, Maria J. Pelaez-Soni, Prashant Dogra, Brian A. Menegaz, Lee B. Jordan, Colin A. Purdie, Philip R. Quinlan, Chandandeep Nagi, Karla A. Sepulveda, Philipp Oertle, Tobias A. Appenzeller, Shu-Hsia Chen, Marko Loparic, Zhihui Wang, Vittorio Cristini, Marija Plodinec, Alastair M. Thompson. Spatial patterns of microenvironmental biomarkers drive long-term breast cancer outcome [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1963.

Abstract 6342: Pan-cancer analysis of promoter or promoter-proximal somatic mutations defines transcription-replication conflict mutational signature

Abstract Introduction: While the nature of somatic mutations in cancer exomes has been described, mutations in non-coding regions are less well-characterized. Compared to the rest of the genome, promoter or promoter-proximal (PPP) regions are more susceptible to mutagenesis and distinct mutational processes [e.g., transcription-replication conflicts (TRCs)]. We sought to investigate the nature of mutations in PPP regions across human cancer types and to define a novel TRC mutational signature. Methods: Whole genome and RNA sequencing data for untreated primary cancers were downloaded from the International Cancer Genome Consortium repository. PPP regions were defined as 1kb upstream of transcription start sites. We quantified the number of mutations in 1) PPP regions, 2) PPP regions of highly transcribed genes (HTGs; ≥75th percentile), and 3) common fragile sites (CFS). Results: A total of 835 patients across 12 tumor types were included in our analysis. Our data show significant variation in PPP mutations across cancer types with liver, pancreatic, and ovarian cancers demonstrating the highest burden of PPP mutations (Table 1). These same cancer types also possessed high numbers of PPP mutations specifically in HTGs. Since PPP mutations may be caused by TRCs, we proposed that liver, pancreatic, and ovarian cancers exhibited a strong TRC mutational signature. Therefore, we examined the correlation between the signature and CFS mutations—known to be caused by TRCs—to validate our results. The data show a positive correlation across tumor types; this correlation was strongest for cancer types where a TRC signature was more prevalent [correlation coefficient (R): liver: 0.985, pancreas: 0.991, ovary: 0.964]. Conclusions: Our analysis of PPP and CFS mutations suggests that transcription-dependent genome instability is more prevalent in liver, pancreatic, and ovarian cancers. Further, PPP in HTGs may be a novel TRC mutational signature. Medians and interquartile ranges of mutations by disease type. PPP: promoter or promoter-proximal Disease type Number of patients Mutations in PPP regions Mutations in PPP regions of highly transcribed genes (≥75%ile) Mutations in common fragile sites Bladder 23 4 (2-8) 2 (1-5) 12 (7-17) Bone 49 5 (2-12) 2 (0-3) 14 (7-43) Breast 89 1 (0-2) 0 (0-2) 5 (2-7) Cervix 20 1 (0-2) 1 (0-1) 3 (2-5) Colorectal 43 2 (1-14) 1 (0-5) 11 (6-81) Liver 227 54 (37-75) 13 (9-18) 264 (180-368) Lung 38 3 (1-6) 1 (0-2) 9 (4-24) Ovary 102 41 (3-68) 36 (16-52) 148 (7-213) Pancreas 140 31 (15-45) 25 (19-37) 113 (66-161) Prostate 19 0 (0-0) 0 (0-0) 1 (0-1) Stomach 34 2 (1-3) 1 (0-2) 8 (3-17) Uterus 51 1 (0-4) 1 (0-3) 6 (3-21) Citation Format: Marc A. Attiyeh, Fan Meng, Yilun Liu, Nicholas Banovich, Mustafa Raoof. Pan-cancer analysis of promoter or promoter-proximal somatic mutations defines transcription-replication conflict mutational signature [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6342.

Can immediate reconstruction with submandibular gland transposition broaden indications for transoral surgery for tonsillar cancer?

e18054 Background: Stratification based on pathologic parameters allows for reduced adjuvant radiotherapy in intermediate risk and observation alone for low risk oropharyngeal p16+ cancer (E3311 ECOG-ACRIN trial). Selection for transoral surgery (TOS), usually robotically assisted, for tonsillar cancers depends on the size and invasiveness of the primary tumor, involvement of adjacent parts such as the soft palate, proximity to external carotid artery branches, medial ipsilateral carotid artery that might be exposed with radical resection, and the likelihood of substantial communication between the oropharynx and internal neck structures. Postoperative recovery can be associated with substantial pain and dysphagia and a length of stay of &gt; 5 days. There is a paucity of simple options for sealing the neck from the pharynx to prevent neck infection, exposure of larger vessels and salivary fistula, so large and deep tonsillar cancers are usually given chemoradiation. Larger surgical defects healing secondarily tend to require longer recoveries due to dysphagia and odynophagia. Methods: A prospective study of vascularized ipsilateral submandibular gland transposition flaps to primarily repair the surgical defect after TOS to resect previously untreated tonsillar cancers was performed from 2019 to 2022. A total of 19 patients underwent resection and repair. These included those with cancers extending to the soft palate (4) and medial position of internal carotid artery adjacent to the tumor (1). All had obvious communication between the neck and the pharynx after TOS, and had branches of the facial and external carotid arteries to the deep resection site ligated with neck dissection, prior to TOS. The submandibular gland flaps were sewn in place using robot assistance and hand. One patient had an extended flap with accompanying submental skin to repair the soft palate. Results: Partial dehiscence superiorly at the palate was the most common complication at 11%. None developed salivary fistulas or deep neck infections. Iatrogenic facial artery pedicle injury that was repaired occurred in one case. Oral intake was started at 1-3 days and length of stay averaged 5 days. There were no bleeding episodes at the TOS sites of cancer resection. All resections had clear margins. All submandibular gland flaps survived, with one patient having attached adipose tissue debrided in the office, healing uneventfully thereafter. Conclusions: The ability to primarily repair after resection of more extensive tonsillar cancers, that leave large communications between the pharynx and the neck, with a readily accessible and easy to harvest submandibular gland flap may change those previously selected for chemoradiation to be able to have TOS instead as initial treatment. This would allow for more pathological risk assessment of tonsil cancers and decreased adjuvant treatment when appropriate.

Preoperative Magnetic Resonance Image and Computerized Tomography Findings Predictive of Facial Nerve Invasion in Patients with Parotid Cancer without Preoperative Facial Weakness-A Retrospective Observational Study.

Simple SummaryFacial nerve invasion in parotid cancer affects survival outcomes as well as functional outcomes after surgery-based treatment. Normal facial muscle function before surgery does not always exclude the possibility of involvement of the facial nerve by a tumor. Especially in patients without facial palsy, accurate evaluation of invasion before surgery is necessary to plan optimal facial nerve resection and reconstruction. Various findings are obtained from preoperative radiological findings, such as CT and MRI. We evaluated the role of these radiological findings in predicting nerve invasion. Large tumor, spiculated margin, and anterolateral location may suggest a high risk of nerve involvement even in patients with normal preoperative facial function. These findings may help surgeons to avoid unexpected facial nerve invasion and to make adequate surgical plans to get optimal oncological and functional outcomes. (1) Background: Facial nerve resection with reconstruction helps achieve optimal outcomes in the treatment of facial nerve invasion (FNI) of parotid cancer. Preoperative imaging is crucial to predict facial nerve reconstruction. The radiological findings of CT or MRI may predict FNI in the parotid cancer even without facial paralysis. Methods: We retrospectively reviewed the records of 151 patients without facial nerve paralysis before surgery who had undergone tumor resection. Previously untreated parotid cancers were included. (2) Results: The median follow-up duration was 62 months (range: 24–120 months). The FNI (+) group (n = 30) showed a significantly worse 5-year overall survival compared with the FNI (−) group (75.5 vs. 93.9%; hazard ratio = 4.19; 95% confidence interval: 1.74–10.08; p = 0.001). The tumor margin, tumor size, presence in the anterolateral parotid region (area 3), retromandibular vein involvement, distance from the stylomastoid foramen to the upper tumor margin, and a high tumor grade were significant factors related to FNI in the univariate analysis. A spiculated tumor margin, the tumor size (2.2 cm), and presence in area 3 were factors predicting FNI in the logistic regression model (p = 0.020, 0.005, and 0.050, respectively; odds ratio: 4.02, 6.40, and 8.16, respectively). (3) Conclusions: The tumor size (≥2.2 cm), spiculated margin, and presence in area 3 as presented in CT and MRI may help clinicians preoperatively predict FNI in patients with parotid cancer and establish an appropriate surgical plan.