Clinical significance of inter-assay discrepancy in PD-L1 evaluation for the efficacy of pembrolizumab in advanced NSCLC with high PD-L1 expression

INTRODUCTION

Programmed cell death ligand-1 (PD-L1) expression is a predictive biomarker for the efficacy of anti-programmed cell death receptor-1/PD-L1 antibodies in advanced non-small cell lung cancer (NSCLC). Although several assays have been approved for evaluating PD-L1 expression status, inter-assay discordance has been observed between some assays. The clinical significance of these discrepancies is still unclear.

METHODS

We retrospectively reviewed treatment-naïve NSCLC patients whose PD-L1 expression was evaluated using both 22C3 and SP142 assays. Among those, efficacy analysis was performed for patients with PD-L1 tumor proportion score (TPS) ≥ 50 % (22C3), who had received first-line pembrolizumab monotherapy. Additionally, transcriptome analysis was conducted in the available tumors with TPS ≥ 50 % to investigate the distinct immune profiles that accompany inter-assay discordance.

RESULTS

In total, 611 patients were eligible. Among 198 patients with TPS ≥ 50 %, 91 (46 %) had tumor cell score ≤ 1 (SP142, i.e., inter-assay discrepancy). In the 52 patients who received first-line pembrolizumab monotherapy, treatment efficacy was significantly lower in patients with the discrepancy than that in those without (objective response rate: 18 % vs. 83 %, p < 0.001; median progression-free survival [months]: 3.2 vs. 8.3, p < 0.001). Transcriptome analysis revealed significantly more CD274 splice variants with aberrant 3'-terminal sequences in tumors with the inter-assay discrepancy than in those without.

CONCLUSION

The inter-assay discrepancy in the PD-L1 status of tumor cells between the 22C3 and SP142 assays, reflecting an imbalance in the CD274 splice variants, could be a biomarker for primary resistance against pembrolizumab monotherapy in high PD-L1-expressing NSCLCs.

Advances in cancer DNA methylation analysis with methPLIER: use of non-negative matrix factorization and knowledge-based constraints to enhance biological interpretability

DNA methylation is an epigenetic modification that results in dynamic changes during ontogenesis and cell differentiation. DNA methylation patterns regulate gene expression and have been widely researched. While tools for DNA methylation analysis have been developed, most of them have focused on intergroup comparative analysis within a dataset; therefore, it is difficult to conduct cross-dataset studies, such as rare disease studies or cross-institutional studies. This study describes a novel method for DNA methylation analysis, namely, methPLIER, which enables interdataset comparative analyses. methPLIER combines Pathway Level Information Extractor (PLIER), which is a non-negative matrix factorization (NMF) method, with regularization by a knowledge matrix and transfer learning. methPLIER can be used to perform intersample and interdataset comparative analysis based on latent feature matrices, which are obtained via matrix factorization of large-scale data, and factor-loading matrices, which are obtained through matrix factorization of the data to be analyzed. We used methPLIER to analyze a lung cancer dataset and confirmed that the data decomposition reflected sample characteristics for recurrence-free survival. Moreover, methPLIER can analyze data obtained via different preprocessing methods, thereby reducing distributional bias among datasets due to preprocessing. Furthermore, methPLIER can be employed for comparative analyses of methylation data obtained from different platforms, thereby reducing bias in data distribution due to platform differences. methPLIER is expected to facilitate cross-sectional DNA methylation data analysis and enhance DNA methylation data resources.

Passive smoking-induced mutagenesis as a promoter of lung carcinogenesis

INTRODUCTION

The International Agency for Research on Cancer has classified passive smoking (PS) or secondhand smoke exposure as a Group 1 carcinogen linked to lung cancer; however, in contrast to active smoking, the mutagenic properties of PS remain unclear.

METHODS

A consecutive cohort of 564 lung adenocarcinoma samples from female never-smokers, who provided detailed information about their exposure to PS during adolescence and in their thirties through a questionnaire, was prepared. Of these, all 291 cases for whom frozen tumor tissues were available were subjected to whole exome sequencing to estimate tumor mutational burden (TMB), and the top 84 cases who were exposed daily, or not, to PS during adolescence and/or in their thirties were further subjected to whole genome sequencing.

RESULTS

A modest yet statistically significant increase in TMB was observed in the group exposed to PS compared with the group not exposed to PS (median values = 1.44 vs. 1.29 per Mb, respectively; p = 0.020). Instead of inducing driver oncogene mutations, PS induced significant subclonal mutations exhibiting APOBEC-type signatures, including SMAD4 and ADGRG6 hotspot mutations. A polymorphic APOBEC3A/3B allele specific to the Asian population that leads to upregulated expression of APOBEC3A accentuated the mutational load in individuals exposed daily to PS during adolescence.

CONCLUSIONS

This study reveals that passive smoking-induced mutagenesis can promote lung carcinogenesis. The APOBEC3A/3B polymorphism may serve as a biomarker for identifying passive non-smoking individuals at high-risk of developing lung cancer.

Rare but clinically important salivary gland-type tumor of the lung: A review

Salivary gland-type tumor (SGT) of the lung, which arises from the bronchial glands of the tracheobronchial tree, was first recognized in the 1950s. SGT represents less than 1% of all lung tumors and is generally reported to have a good prognosis. Mucoepidermoid carcinoma (MEC) and adenoid cystic carcinoma (ACC) are the two most common subtypes, comprising more than 90% of all SGTs. The reported 5-year survival rate of patients with SGT is 63.4%. Because this type of tumor develops in major bronchi, patients with SGT commonly present with symptoms of bronchial obstruction, including dyspnea, shortness of breath, wheezing, and coughing; thus, the tumor is usually identified at an early stage. Most patients are treated by lobectomy and pneumonectomy, but bronchoplasty or tracheoplasty is often needed to preserve respiratory function. Lymphadenectomy in the surgical resection of SGT is recommended, given that clinical benefit from lymphadenectomy has been reported in patients with MEC. For advanced tumors, appropriate therapy should be considered according to the subtype because of the varying clinicopathologic features. MEC, but not ACC, is less likely to be treated with radiation therapy because of its low response rate. Although previous researchers have learned much from studying SGT over the years, the diagnosis and treatment of SGT remains a complex and challenging problem for thoracic surgeons. In this article, we review the diagnosis, prognosis, and treatment (surgery, chemotherapy, and radiotherapy) of SGT, mainly focusing on MEC and ACC. We also summarize reports of adjuvant and definitive radiation therapy for ACC in the literature.

Is 18F-fluorodeoxyglucose PET recommended for small lung nodules? CT findings of 18F-fluorodeoxyglucose non-avid lung cancer

OBJECTIVES

To determine the image characteristics associated with low 18F-FDG (18F-fluorodeoxyglucose) avidity among 8-15 mm solid lung cancer.

METHODS

Patients satisfying the following criteria were included: underwent surgery between January 2014 and December 2019 for lung cancer, presented 8-15 mm nodule without measurable ground glass component on preoperative CT, and underwent 18F-FDG PET before resection. Image characteristics, including air bronchogram, concave shape, pleural attachment, and background emphysema, were evaluated by two board-certified radiologists. The Mann-Whitney U test was used to compare maximum standardized uptake (SUVmax) values from 18F-FDG PET images.

RESULTS

The analysis included 235 patients. The SUVmax values of lesions with air bronchogram and concave shape were significantly lower than the SUVmax values of lesions without these features (median: 1.55 vs 2.56 and 1.66 vs 2.45, both P < .001), whereas lesions arising from emphysematous lungs had significantly higher SUVmax values than lesions arising from non-emphysematous lungs (2.90 vs 1.69, P < .001). No significant differences were detected between lesions attached and not attached to pleura. The interobserver agreement was almost perfect for air bronchograms and background emphysema (κ = 0.882 and 0.927, respectively), and 89.7% of lesions with air bronchograms and arising from non-emphysematous lungs showed SUVmax values below 2.5.

CONCLUSIONS

Among 8-15 mm solid lung cancer, the presence of air bronchograms and concave shape and the absence of background emphysema were associated with low 18F-FDG accumulation.

ADVANCES IN KNOWLEDGE

18F-FDG PET can be misleading in differentiating certain type of small solid lung cancer.

Genomic Staging of Multifocal Lung Squamous Cell Carcinomas Is Independent of the Comprehensive Morphologic Assessment

INTRODUCTION

Morphologic and molecular data for staging of multifocal lung squamous cell carcinomas (LSCCs) are limited. In this study, whole exome sequencing (WES) was used as the gold standard to determine whether multifocal LSCC represented separate primary lung cancers (SPLCs) or intrapulmonary metastases (IPMs). Genomic profiles were compared with the comprehensive morphologic assessment.

METHODS

WES was performed on 20 tumor pairs of multifocal LSCC and matched normal lymph nodes using the Illumina NovaSeq6000 S4-Xp (Illumina, San Diego, CA). WES clonal and subclonal analysis data were compared with histologic assessment by 16 thoracic pathologists. In addition, the immune gene profiling of the study cases was characterized by the HTG EdgeSeq Precision Immuno-Oncology Panel.

RESULTS

By WES data, 11 cases were classified as SPLC and seven cases as IPM. Two cases were technically suboptimal. Analysis revealed marked genomic and immunogenic heterogeneity, but immune gene expression profiles highly correlated with mutation profiles. Tumors classified as IPM have a large number of shared mutations (ranging from 33.5% to 80.7%). The agreement between individual morphologic assessments for each case and WES was 58.3%. One case was unanimously interpreted morphologically as IPM and was in agreement with WES. In a further 17 cases, the number of pathologists whose morphologic interpretation was in agreement with WES ranged from two (one case) to 15 pathologists (one case) per case. Pathologists showed a fair interobserver agreement in the morphologic staging of multiple LSCCs, with an overall kappa of 0.232.

CONCLUSIONS

Staging of multifocal LSCC based on morphologic assessment is unreliable. Comprehensive genomic analyses should be adopted for the staging of multifocal LSCC.

Optimizing tissue stewardship in non-small cell lung cancer to support molecular characterization and treatment selection: statement from a working group of thoracic pathologists

Many patients with non-small cell lung cancer do not receive guideline-recommended, biomarker-directed therapy, despite the potential for improved clinical outcomes. Access to timely, accurate, and comprehensive molecular profiling, including targetable protein overexpression, is essential to allow fully informed treatment decisions to be taken. In turn, this requires optimal tissue management to protect and maximize the use of this precious finite resource. Here, a group of leading thoracic pathologists recommend factors to consider for optimal tissue management. Starting from when lung cancer is first suspected, keeping predictive biomarker testing in the front of the mind should drive the development of practices and procedures that conserve tissue appropriately to support molecular characterization and treatment selection.

Inflammatory Rhabdomyoblastic Tumor: Clinicopathologic and Molecular Analysis of 13 Cases

Inflammatory rhabdomyoblastic tumors (IRMTs) are newly recognized skeletal muscle tumors with uncertain malignant potential. We investigated 13 IRMTs using clinicopathologic, genetic, and epigenetic methods. The cohort included 7 men and 6 women, aged 23 to 80 years (median, 50 years), of whom 2 had neurofibromatosis type 1. Most tumors occurred in the deep soft tissues of the lower limbs, head/neck, trunk wall, and retroperitoneum/pelvis. Two tumors involved the hypopharyngeal submucosa as polypoid masses. Eight tumors showed conventional histology of predominantly spindled cells with nuclear atypia, low mitotic activity, and massive inflammatory infiltrates. Three tumors showed atypical histology, including uniform epithelioid or plump cells and mitotically active histiocytes. The remaining 2 tumors demonstrated malignant progression to rhabdomyosarcoma; one had additional IRMT histology and the other was a pure sarcoma. All 11 IRMTs without malignant progression exhibited indolent behavior at a median follow-up of 43 months. One of the 2 patients with IRMTs with malignant progression died of lung metastases. All IRMTs were positive for desmin and PAX7, whereas myogenin and MyoD1 were expressed in a subset of cases. Targeted next-generation sequencing identified pathogenic mutations in NF1 (5/8) and TP53 (4/8). All TP53 mutations co-occurred with NF1 mutations. TP53 variant allele frequency was much lower than that of NF1 in 2 cases. These tumors showed geographic (subclonal) strong p53 immunoreactivity, suggesting the secondary emergence of a TP53-mutant clone. DNA methylation-based copy number analysis conducted in 11 tumors revealed characteristic flat patterns with relative gains, including chromosomes 5, 18, 20, 21, and/or 22 in most cases. Widespread loss of heterozygosity with retained biparental copies of these chromosomes was confirmed in 4 tumors analyzed via allele-specific profiling. Based on unsupervised DNA methylation analysis, none of the 11 tumors tested clustered with existing reference entities but formed a coherent group, although its specificity warrants further study.

Impact of 18F-FDG PET on TNM Staging and Prognosis in Thymic Epithelial Tumors

BACKGROUND

Preoperative fluorine-18-fluorodeoxyglucose positron emission tomography (18F-FDG PET) of thymic epithelial tumors (TETs) is well known for identifying malignant-grade TETs; however, its predictive power for determining locally advanced tumors, lymph node (LN) metastasis, and prognosis remains unknown.

PATIENTS AND METHODS

We retrospectively evaluated patients with resectable TETs who were preoperatively assessed using 18F-FDG PET from January 2012 to January 2023. The receiver operating characteristic curve was used to evaluate the cutoff value of the maximum standardized uptake value (SUVmax) to predict advanced-stage disease. Recurrence/progression-free survival (RFS/PFS) was analyzed using the Kaplan-Meier method. The staging was classified according to the tumor-node-metastasis system.

RESULTS

Our study included 177 patients; 145 (81.9%) had pathological early-stage TET (stage I or II), and 32 (19.1%) had advanced stage (stage III or IV). The area under the curve value for predicting the advanced stage was 0.903, and the cutoff value was 5.6 (sensitivity 81.3%, specificity 84.8%). SUVmax > 5.6 was associated with worse prognosis for RFS/PFS. LN metastasis was preoperatively detected by FDG uptake in 30.8% of patients with pathological LN positivity, whereas LN metastasis was not pathologically detected in patients with SUVmax < 5.9. In patients with advanced-stage TETs, LN recurrence was more frequent in patients who were preoperatively detected by 18F-FDG PET than those who were not (75.0% versus 7.1%).

CONCLUSIONS

18F-FDG PET is a potentially valuable tool for predicting advanced stage and poor prognosis of recurrence in patients with TETs. SUVmax can help thoracic surgeons to guide them in selecting appropriate therapeutic strategies for TETs.

Molecular pathology of non-small cell carcinoma

Currently, lung cancer is treated by the highest number of therapeutic options and the benefits are based on multiple large-scale sequencing studies, translational research and new drug development, which has promoted our understanding of the molecular pathology of lung cancer. According to the driver alterations, different characteristics have been revealed, such as differences in ethnic prevalence, median age and alteration patterns. Consequently, beyond traditional chemoradiotherapy, molecular-targeted therapy and treatment with immune check-point inhibitors (ICI) also became available major therapeutic options. Interestingly, clinical results suggest that the recently established therapies target distinct lung cancer proportions, particularly between the EGFR/ALK and PD-1/PD-L1-positive subsets, e.g. the kinase inhibitors target driver mutation-positive tumours, whereas driver mutation-negative tumours respond to ICI treatment. These therapeutic efficacy-related differences might be explained by the molecular pathogenesis of lung cancer. Addictive driver mutations promote tumour formation with powerful transformation performance, resulting in a low tumour mutation burden, reduced immune surveillance, and subsequent poor response to ICIs. In contrast, regular tobacco smoke exposure repeatedly injures the proximal airway epithelium, leading to accumulated genetic alterations. In the latter pathway, overgrowth due to alteration and immunological exclusion against neoantigens is initially balanced. However, tumours could be generated from certain clones that outcompete immunological exclusion and outgrow the others. Consequently, this cancer type responds to immune check-point treatment. These pathogenic differences are explained well by the two-compartment model, focusing upon the anatomical and functional composition of distinct cellular components between the terminal respiratory unit and the air-conducting system.

Myxoid liposarcoma with nuclear pleomorphism: a clinicopathological and molecular study

Myxoid liposarcoma (MLS) is a common type of liposarcoma. It is characterized by variably lipogenic uniform cells in myxoid stroma with arborizing capillaries and DDIT3 fusion. Nuclear uniformity is the rule, which is maintained even in high-grade round cell examples. In this study, we conducted an in-depth investigation of four MLS tumors that demonstrated nuclear pleomorphism in three patients. These cases accounted for 2.1% of 142 patients with MLS. All patients were male aged 26, 33, and 49 years. Nuclear pleomorphism was observed in both primary and metastatic tumors in one patient, a primary tumor in one patient, and a metastatic tumor in another patient. Pleomorphism was severe in three tumors and moderate in one. Histology resembled that of dedifferentiated liposarcoma with myxoid features, pleomorphic liposarcoma with myxoid features, or myxoid pleomorphic liposarcoma in two tumors, pleomorphic sarcoma with focal cartilaginous and rhabdomyoblastic differentiation in one tumor, and epithelioid pleomorphic liposarcoma in one tumor. All tumors harbored FUS::DDIT3 fusions and immunohistochemically expressed DDIT3. All tumors had TP53 mutations, whereas previous specimens with uniform cytology from the same patients lacked TP53 mutations. One tumor showed RB1 deletion and complete loss of Rb expression, which was unclassifiable using DNA methylation-based methods. The rare occurrence of nuclear pleomorphism is underrecognized in MLS and increases the complexity to the diagnosis of liposarcoma. DDIT3 evaluation can be liberally considered in liposarcoma assessment even in the presence of nuclear pleomorphism.

Whole-genome sequencing reveals the molecular implications of the stepwise progression of lung adenocarcinoma

The mechanism underlying the development of tumors, particularly at early stages, still remains mostly elusive. Here, we report whole-genome long and short read sequencing analysis of 76 lung cancers, focusing on very early-stage lung adenocarcinomas such as adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma. The obtained data is further integrated with bulk and spatial transcriptomic data and epigenomic data. These analyses reveal key events in lung carcinogenesis. Minimal somatic mutations in pivotal driver mutations and essential proliferative factors are the only detectable somatic mutations in the very early-stage of AIS. These initial events are followed by copy number changes and global DNA hypomethylation. Particularly, drastic changes are initiated at the later AIS stage, i.e., in Noguchi type B tumors, wherein cancer cells are exposed to the surrounding microenvironment. This study sheds light on the pathogenesis of lung adenocarcinoma from integrated pathological and molecular viewpoints.

Dynamics of recurrence after curative resection of nonsmall cell lung cancer

BACKGROUND AND OBJECTIVES

This study examined the trend of hazards for postoperative recurrence of lung cancer according to pathologic stages.

METHODS

We reviewed the records of 1987 patients who underwent resection for lung cancer between 2007 and 2012. Postoperative recurrence and development of second primary lung cancer were analyzed to evaluate the trend of hazard rate.

RESULTS

Recurrence-free survival (RFS) probabilities at 5 postoperative years in patients with stage I/II/III disease were 87.8%/54.7%,/33.4%, respectively. The hazard rate of RFS was consistently low (<0.005) for stage I patients for 5 years after surgery. The hazard rate of RFS for stage II patients showed a peak of 0.016 at 12.4 months after surgery, and that for stage III patients had a higher peak of 0.029 at 13.7 months after surgery, after which they showed a gradual decrease. The hazard rate for the development of second primary lung cancer exceeded that of recurrence of first primary lung cancer after 72 months postoperatively.

CONCLUSIONS

Short-interval postoperative surveillance might be unnecessary for stage I patients but should be considered in stage II/III patients. Screening of second primary lung cancer rather than surveillance of recurrence might be beneficial after more than 6 years postoperatively.

Strategic Approach to Heterogeneity Analysis of Cutaneous Adnexal Carcinomas Using Computational Pathology and Genomics

Cutaneous adnexal tumors are neoplasms that arise from skin appendages. Their morphologic diversity and phenotypic variability with rare progression to malignancy make them difficult to diagnose and classify, and there is currently no established treatment strategy. To overcome these difficulties, this study investigated the transcription factor SOX9 expression, morphology, and genetics of skin adnexal tumors for understanding their biology, especially their histogenesis. We showed that cutaneous adnexal tumors and their nontumor counterparts of skin and appendages exhibit expression patterns similar to that of SOX9. Its expression intensity and pattern, as well as histopathologic evaluation of tumors, were analyzed using digital images of 69 normal skin adnexal 9-type organs and 185 skin adnexal 29-type tumors as references. It was possible to distinguish basal cell carcinoma from squamous cell carcinoma, sebaceous carcinoma, and pilomatrixoma with significant differences, along with porocarcinoma from squamous cell carcinoma. Furthermore, unsupervised machine learning "computational pathology" was used to derive a multiregion whole-exome sequencing fusion method termed "genocomputed pathology." The genocomputed pathology of three representable adnexal carcinomas (porocarcinoma, hidradenocarcinoma, and spiradenocarcinoma) was evaluated for total nine cases. We showed that there was more heterogeneity than expected within the tumors as well as the coexistence of components lacking driver fusion genes. The presence or absence of potential driver genes, such as PIK3CA, YAP1, and PTEN, in each region was identified, highlighting a therapeutic strategy for cutaneous adnexal carcinoma encompassing heterogeneous tumors.

Genome Doubling Shapes High-Grade Transformation and Novel EWSR1::LARP4 Fusion Shows SOX10 Immunostaining in Hyalinizing Clear Cell Carcinoma of Salivary Gland

Hyalinizing clear cell carcinoma (HCCC) is a rare indolent malignant tumor of minor salivary gland origin with EWSR1::ATF1 rearrangement. Pathologically, the tumor cells possess a clear cytoplasm in a background of hyalinized stroma. Generally, the tumor cells are positive for p63 and p40 and negative for s100 and α-smooth muscle actin, suggesting that they differentiate into squamous epithelium and not into myoepithelium. In this study, we performed a detailed histopathological and genomic analysis of 6 cases of HCCC, including 2 atypical subtypes-a case of "high-grade transformation" and 1 "possessing a novel partner gene for EWSR1." We performed a sequential analysis of the primary and recurrent tumor by whole-exome sequencing, RNA sequencing, Sanger sequencing, and fluorescence in situ hybridization to investigate the effect of genomic changes on histopathology and clinical prognosis. A fusion gene involving the EWSR1 gene was detected in all cases. Five cases, including the "high-grade transformation," harbored a known EWSR1::ATF1 fusion gene; however, 1 case harbored a novel EWSR1::LARP4 fusion gene. This novel EWSR1::LARP4-fused HCCC has a SOX10-positive staining, which is different from the EWSR1::ATF1-fused HCCC. According to whole-exome sequencing and fluorescence in situ hybridization analysis, the "whole-genome doubling" and focal deletion involving CDKN2A, CDKN2B, and PTEN were detected in HCCC with "high-grade transformation." Conclusively, we identified a novel partner gene for EWSR1, LARP4, in indolent HCCC. Importantly, "high-grade transformation" and poor prognosis were caused by whole-genome doubling and subsequent genomic aberrations.

A comprehensive appraisal of HER2 heterogeneity in HER2-amplified and HER2-low colorectal cancer

BACKGROUND

This study aimed to elucidate the clinicopathological and molecular features of HER2-amplified and HER2-low colorectal cancers (CRCs). We also characterised HER2 expression statuses in CRCs focusing on their intratumoral heterogeneity and alterations in metastatic lesions to establish practical HER2 status assessment.

METHODS

We evaluated 1009 CRCs for HER2 expression and HER2 amplification by immunohistochemistry and FISH, respectively, and correlated the results to clinicopathological and molecular data. For HER2-positive tumours, HER2 expression in metastatic lesions was also assessed.

RESULTS

Twenty-five HER2-amplified (2.5%) and 46 HER2-low tumours (4.6%) were identified. HER2-amplified tumours consistently lacked a mucinous component and HER2-low tumours tended to be in the right colon, but no other clinicopathological features were noted. KRAS, NRAS or BRAF mutations were detected in only two HER2-amplified tumours (8%), whereas 23 HER2-low tumours (50%) had one of these mutations. Most HER2-amplified and HER2-low tumours showed a homogeneous or mosaic HER2 expression pattern and a clustered heterogeneous expression pattern was rather rare. HER2 expression was maintained in most metastatic lesions in both HER2-amplified (93%) and HER2-low tumours (81%).

CONCLUSIONS

These results suggest that biopsy-based assessment of primary lesions is appropriate for the identification of CRC patients eligible for systemic HER2-targeted therapy.

KRAS G12C in advanced NSCLC: Prevalence, co-mutations, and testing

KRAS is the most commonly mutated oncogene in advanced, non-squamous, non-small cell lung cancer (NSCLC) in Western countries. Of the various KRAS mutants, KRAS G12C is the most common variant (~40%), representing 10-13% of advanced non-squamous NSCLC. Recent regulatory approvals of the KRASG12C-selective inhibitors sotorasib and adagrasib for patients with advanced or metastatic NSCLC harboring KRASG12C have transformed KRAS into a druggable target. In this review, we explore the evolving role of KRAS from a prognostic to a predictive biomarker in advanced NSCLC, discussing KRAS G12C biology, real-world prevalence, clinical relevance of co-mutations, and approaches to molecular testing. Real-world evidence demonstrates significant geographic differences in KRAS G12C prevalence (8.9-19.5% in the US, 9.3-18.4% in Europe, 6.9-9.0% in Latin America, and 1.4-4.3% in Asia) in advanced NSCLC. Additionally, the body of clinical data pertaining to KRAS G12C co-mutations such as STK11, KEAP1, and TP53 is increasing. In real-world evidence, KRAS G12C-mutant NSCLC was associated with STK11, KEAP1, and TP53 co-mutations in 10.3-28.0%, 6.3-23.0%, and 17.8-50.0% of patients, respectively. Whilst sotorasib and adagrasib are currently approved for use in the second-line setting and beyond for patients with advanced/metastatic NSCLC, testing and reporting of the KRAS G12C variant should be included in routine biomarker testing prior to first-line therapy. KRAS G12C test results should be clearly documented in patients' health records for actionability at progression. Where available, next-generation sequencing is recommended to facilitate simultaneous testing of potentially actionable biomarkers in a single run to conserve tissue. Results from molecular testing should inform clinical decisions in treating patients with KRAS G12C-mutated advanced NSCLC.

Japanese Society of Medical Oncology/Japan Society of Clinical Oncology/Japanese Society of Pediatric Hematology/Oncology-led clinical recommendations on the diagnosis and use of immunotherapy in patients with DNA mismatch repair deficient (dMMR) tumors, third edition

BACKGROUND

Clinical trials have reported the efficacy of immune checkpoint inhibitors in the treatment of mismatch repair-deficient (dMMR) advanced solid tumors. The accumulated evidence of tumor agnostic agent has been made since PD-1 inhibitor was approved and used in clinical practice. Therefore, we have revised the guideline "Japan Society of Clinical Oncology provisional clinical opinion for the diagnosis and use of immunotherapy in patients with deficient DNA mismatch repair tumors, cooperated by Japanese Society of Medical Oncology, First Edition".

METHODS

Clinical questions regarding medical care were formulated for patients with dMMR advanced solid tumors. Relevant publications were searched by PubMed and Cochrane Database. Critical publications and conference reports were added manually. Systematic reviews were performed for each clinical question for the purpose of developing clinical recommendations. The committee members identified by Japan Society of Clinical Oncology (JSCO), Japanese Society of Medical Oncology (JSMO), and Japanese society of pediatric hematology/oncology (JSPHO) voted to determine the level of each recommendation considering the strength of evidence, expected risks and benefits to patients, and other related factors. Thereafter, a peer review by experts nominated from JSCO, JSMO, and JSPHO and the public comments among all societies' members were done.

RESULTS

The current guideline describes two clinical questions and eight recommendations for whom, when, and how MMR status should be tested.

CONCLUSION

In this guideline, the committee proposed eight recommendations for performing MMR testing properly to select patients who are likely to benefit from immunotherapy.

Whole Exome Sequencing of Thymoma Patients Exhibiting Exceptional Responses to Pemetrexed Monotherapy

BACKGROUND

Pemetrexed is used for the chemotherapy of advanced thymoma. Exceptional responses of thymoma to pemetrexed treatment are not frequently observed. The underlying genetic mechanism of the exceptional responses remains unclear. We used whole-exome sequencing to explore the specific genomic aberrations that lead to an extreme and durable response.

METHODS

Whole-exome sequencing using NovaSeq6000 (150 bp paired-end sequencing) was performed on nine formalin-fixed paraffin-embedded tissues from patients with advanced thymomas treated with pemetrexed (two exceptional responders and seven typical responders).

RESULTS

We identified 284 somatic single-nucleotide variants (SNVs; 272 missense, 8 missense/splice-site, 3 stop-gain, and 1 stop-gain/splice-site), 34 insertions and deletions (Indels; 33 frameshift and one splice region), and 21 copy number variations (CNVs; 15 gains and six losses). No difference in the number of SNVs variants and distribution of deleterious Indels was observed between the exceptional and typical responders. Interestingly, arm-level chromosomal CNVs (15 gains and six losses) were detected in four patients, including an exceptional responder. The highest number of arm-level CNVs was observed in an exceptional responder.

CONCLUSION

Exceptional responders to pemetrexed for metastatic thymomas may be characterized by arm-level CNVs. Further, whole-genome and RNA sequencing studies should be performed.

Japanese Society of Medical Oncology/Japan Society of Clinical Oncology/Japanese Society of Pediatric Hematology/Oncology-led clinical recommendations on the diagnosis and use of immunotherapy in patients with high tumor mutational burden tumors

The development of novel antitumor agents and accompanying biomarkers has improved survival across several tumor types. Previously, we developed recommendations for tumor-agnostic treatments in patients with solid tumors with DNA mismatch repair deficient or neurotrophic receptor tyrosine kinase fusions. Recently, immune checkpoint inhibitors have shown efficacy in patient with tumor mutation burden-high (TMB-H) solid tumors and have been established as a third tumor-agnostic agent, making it necessary to develop the guideline prioritized for these patients. Clinical questions regarding medical care were formulated for patients with TMB-H advanced solid tumors. Relevant publications were searched by PubMed and Cochrane Database. Critical publications and conference reports were added manually. Systematic reviews were performed for each clinical question for the purpose of developing clinical recommendations. The committee members identified by Japan Society of Clinical Oncology (JSCO), Japanese Society of Medical Oncology (JSMO), and Japanese society of pediatric hematology/oncology (JSPHO) voted to determine the level of each recommendation considering the strength of evidence, expected risks and benefits to patients, and other related factors. Thereafter, a peer review by experts nominated from JSCO, JSMO, and JSPHO, and the public comments among all societies' members was done. The current guideline describes three clinical questions and seven recommendations for whom, when, and how TMB should be tested, and what is recommended for patients with TMB-H advanced solid tumors. In this guideline, the committee proposed seven recommendations for performing TMB testing properly to select patients who are likely to benefit from immunotherapy.

Clinical and pathological features of second primary neoplasms arising in head and neck reconstructive skin flaps

The incidence of second primary neoplasms arising in the skin reconstructive flap (SNAF) is increasing because of the increase in head and neck flap reconstruction and cancer survival. Prognosis, optimal treatment, and their clinicopathological-genetic features are under debate and are difficult to diagnose. We retrospectively reviewed SNAFs based on a single center's experience over 20 years. Medical records and specimens of 21 patients with SNAF who underwent biopsies between April 2000 and April 2020 at our institute were retrospectively analyzed. Definite squamous cell carcinoma and the remaining neoplastic lesions were subclassified as flap cancer (FC) and precancerous lesions (PLs), respectively. Immunohistochemical studies focused on p53 and p16. TP53 sequencing was conducted using next-generation sequencing. Seven and 14 patients had definite FC and PL, respectively. The mean number of biopsies/latency intervals was 2.0 times/114 months and 2.5 times/108 months for FC and PL, respectively. All lesions were grossly exophytic and accompanied by inflamed stroma. In FC and PL, the incidences of altered p53 types were 43% and 29%, respectively, and those of positive p16 stains were 57% and 64%, respectively. Mutation of TP53 in FC and PL were 17% and 29%, respectively. All except one patient with FC under long-term immunosuppressive therapy survived in this study. SNAFs are grossly exophytic tumors with an inflammatory background and show a relatively low altered p53 and TP53 rate and a high p16 positivity rate. They are slow-growing neoplasms with good prognoses. Diagnosis is often difficult; therefore, repeated or excisional biopsy of the lesion may be desirable.

Pediatric Precision Medicine at the National Cancer Center Japan: Prospective Genomic Study of Pediatric Patients with Cancer as Part of the TOP-GEAR Project

PURPOSE

This single-center, prospective molecular profiling study characterizes genomic alterations and identifies therapeutic targets in advanced pediatric solid tumors.

METHODS

As part of the TOP-GEAR (Trial of Onco-Panel for Gene profiling to Estimate both Adverse events and Response by cancer treatment) project at the National Cancer Center (NCC), Japan, we enrolled pediatric patients with a refractory or recurrent disease during August 2016-December 2021 and performed genomic analysis of matched tumors and blood using originally developed cancer gene panels, NCC Oncopanel (ver. 4.0) and NCC Oncopanel Ped (ver. 1.0).

RESULTS

Of 142 patients (age, 1-28 years) enrolled, 128 (90%) were evaluable for genomic analysis; 76 (59%) patients harbored at least one reportable somatic or germline alteration. The tumor samples were collected during the initial diagnosis in 65 (51%) patients, after treatment initiation in 11 (9%) patients, and upon either disease progression or relapse in 52 (41%) patients. The leading altered gene was TP53, followed by MYCN, MYC, CDKN2A, and CDK4. The commonly affected molecular processes were transcription, cell-cycle regulation, epigenetic modifiers, and RAS/mitogen-activated protein kinase signaling. Twelve (9%) patients carried pathogenic germline variants in cancer-predisposing genes. Potentially actionable findings were identified in 40 (31%) patients; to date, 13 (10%) patients have received the recommended therapy on the basis of their genomic profiles. Although four patients had access to targeted therapy through clinical trials, the agents were used in nine patients in an off-label setting.

CONCLUSION

The implementation of genomic medicine has furthered our understanding of tumor biology and provided new therapeutic strategies. However, the paucity of proposed agents limits the full potential of actionability, emphasizing the significance of facilitating access to targeted cancer therapies.

Concordance between cryobiopsy and forceps biopsy specimens in assessment of immunohistochemistry staining for non-small cell lung carcinoma

Background

Cryobiopsy is recently being promoted for biopsy of tumors in the lung periphery in precision medicine for lung cancer; the obtained tissue samples have been reported to be more useful compared to those obtained using forceps, because of the larger volume and higher quality. However, the influence of freezing and thawing of tissues when performing cryobiopsy on the results of immunohistochemistry (IHC) has not been completely understood.

Methods

In this study, consecutive patients who underwent diagnostic bronchoscopy with cryobiopsy for peripheral pulmonary lesions (PPLs) at our institution between June 2017 and November 2021 were reviewed retrospectively. Specimens of diagnosed cases of unresectable or recurrent non-small cell lung carcinoma (NSCLC) were selected. We compared the results of IHC assessment for programmed death-ligand 1 (PD-L1), human epidermal growth factor receptor 2 (HER2), and human epidermal growth factor receptor 3 (HER3) in cryobiopsy specimens versus conventional forceps biopsy specimens from the same site in the same procedure.

Results

Twenty-four of 40 patients were male (60%). The most frequent histologic type of cancer was adenocarcinoma (n=31, 77.5%), followed by NSCLC (n=4, 10%), squamous cell carcinoma (n=3, 7.5%), and others (n=2, 5%). The concordance rates of the tumor proportion scores (TPSs) for PD-L1, IHC score for HER2 and, IHC scores for HER3 were 85%, 72.5%, and 75%, respectively; the weighted kappa were 0.835, 0.637, and 0.697, respectively.

Conclusions

Freezing and thawing associated with cryobiopsy had virtually no effect on the results of IHC. We suggest that cryobiopsy specimens would therefore be ideal for precision medicine and translational research.

Genome-wide association study of lung adenocarcinoma in East Asia and comparison with a European population

Lung adenocarcinoma is the most common type of lung cancer. Known risk variants explain only a small fraction of lung adenocarcinoma heritability. Here, we conducted a two-stage genome-wide association study of lung adenocarcinoma of East Asian ancestry (21,658 cases and 150,676 controls; 54.5% never-smokers) and identified 12 novel susceptibility variants, bringing the total number to 28 at 25 independent loci. Transcriptome-wide association analyses together with colocalization studies using a Taiwanese lung expression quantitative trait loci dataset (n = 115) identified novel candidate genes, including FADS1 at 11q12 and ELF5 at 11p13. In a multi-ancestry meta-analysis of East Asian and European studies, four loci were identified at 2p11, 4q32, 16q23, and 18q12. At the same time, most of our findings in East Asian populations showed no evidence of association in European populations. In our studies drawn from East Asian populations, a polygenic risk score based on the 25 loci had a stronger association in never-smokers vs. individuals with a history of smoking (Pinteraction = 0.0058). These findings provide new insights into the etiology of lung adenocarcinoma in individuals from East Asian populations, which could be important in developing translational applications.

Japanese Society of Medical Oncology/Japan Society of Clinical Oncology/Japanese Society of Pediatric Hematology/Oncology-led clinical recommendations on the diagnosis and use of tropomyosin receptor kinase inhibitors in adult and pediatric patients with neurotrophic receptor tyrosine kinase fusion-positive advanced solid tumors

BACKGROUND

Clinical trials have reported the efficacy of tropomyosin receptor kinase (TRK) inhibitors against neurotrophic receptor tyrosine kinase (NTRK) fusion gene-positive advanced solid tumors. The accumulated evidence of tumor-agnostic agent has made since TRK inhibitors were approved and used in clinical practice. Therefore, we have revised the 'Japan Society of Clinical Oncology (JSCO)/Japanese Society of Medical Oncology (JSMO)-led clinical recommendations on the diagnosis and use of tropomyosin receptor kinase inhibitors in adult and pediatric patients with neurotrophic receptor tyrosine kinase fusion-positive advanced solid tumors, cooperated by the Japanese Society of Pediatric Hematology/Oncology (JSPHO)'.

METHODS

Clinical questions regarding medical care were formulated for patients with NTRK fusion-positive advanced solid tumors. Relevant publications were searched by PubMed and Cochrane Database. Critical publications and conference reports were added manually. Systematic reviews were performed for each clinical question for the purpose of developing clinical recommendations. The committee members identified by JSCO, JSMO, and JSPHO voted to determine the level of each recommendation considering the strength of evidence, expected risks and benefits to patients, and other related factors. Thereafter, a peer review by experts nominated from JSCO, JSMO, and JSPHO, and the public comments among all societies' members was done.

RESULTS

The current guideline describes 3 clinical questions and 14 recommendations for whom, when, and how NTRK fusion should be tested, and what is recommended for patients with NTRK fusion-positive advanced solid tumors.

CONCLUSION

The committee proposed 14 recommendations for performing NTRK testing properly to select patients who are likely to benefit from TRK inhibitors.

Role of 18F-FDG PET in selecting candidates for a minimally invasive approach for thymic epithelial tumour resection

OBJECTIVES

We evaluated the potential of preoperative fluorine-18-fluorodeoxyglucose positron emission tomography (18F-FDG PET) to predict invasive thymic epithelial tumours in patients with computed tomography (CT)-defined clinical stage I thymic epithelial tumours ≤5 cm in size who are generally considered to be candidates for minimally invasive approaches.

METHODS

From January 2012 to July 2022, we retrospectively analysed patients who exhibited tumor-node-metastasis (TNM) clinical stage I thymic epithelial tumours with lesion sizes ≤5 cm as determined by CT. All patients underwent 18F-FDG PET preoperatively. We analysed the association of maximum standardized uptake values (SUVmax) with both the World Health Organization histological classification and the TNM staging classification.

RESULTS

A total of 107 patients with thymic epithelial tumours (thymomas, 91; thymic carcinomas, 14; carcinoids, 2) were evaluated. Nine patients (8.4%) were pathologically upstaged: TNM pathological stage II in three (2.8%), III in four (3.7%), and IV in two (1.9%). Among these nine upstaged patients, five had thymic carcinoma with stage III/IV, three had type B2/B3 thymoma with stage II/III, and one had type B1 thymoma with stage II. SUVmax was a predictive factor that distinguished pathological stage > I thymic epithelial tumours from pathological stage I (best cut-off value, 4.2; area under the curve [AUC] = 0.820) and thymic carcinomas from other thymic tumours (best cut-off value, 4.5; AUC = 0.882).

CONCLUSIONS

Thoracic surgeons should carefully determine the surgical approach for high FDG-uptake thymic epithelial tumours and keep in mind the issues associated with thymic carcinoma and potential combined resections of neighbouring structures.

The evolution of cancer genomic medicine in Japan and the role of the National Cancer Center Japan

The journey to implement cancer genomic medicine (CGM) in oncology practice began in the 1980s, which is considered the dawn of genetic and genomic cancer research. At the time, a variety of activating oncogenic alterations and their functional significance were unveiled in cancer cells, which led to the development of molecular targeted therapies in the 2000s and beyond. Although CGM is still a relatively new discipline and it is difficult to predict to what extent CGM will benefit the diverse pool of cancer patients, the National Cancer Center (NCC) of Japan has already contributed considerably to CGM advancement for the conquest of cancer. Looking back at these past achievements of the NCC, we predict that the future of CGM will involve the following: 1) A biobank of paired cancerous and non-cancerous tissues and cells from various cancer types and stages will be developed. The quantity and quality of these samples will be compatible with omics analyses. All biobank samples will be linked to longitudinal clinical information. 2) New technologies, such as whole-genome sequencing and artificial intelligence, will be introduced and new bioresources for functional and pharmacologic analyses (e.g., a patient-derived xenograft library) will be systematically deployed. 3) Fast and bidirectional translational research (bench-to-bedside and bedside-to-bench) performed by basic researchers and clinical investigators, preferably working alongside each other at the same institution, will be implemented; 4) Close collaborations between academia, industry, regulatory bodies, and funding agencies will be established. 5) There will be an investment in the other branch of CGM, personalized preventive medicine, based on the individual's genetic predisposition to cancer.

Abstract 3995: Trastuzumab deruxtecan, antibody-drug conjugate targeting HER2, effectively inhibits growth of patient-derived xenograft model with CIC-rearranged sarcoma

Background: Capicua-double homeobox 4 (CIC-DUX4)-rearranged sarcomas (CDS) are extremely rare and highly aggressive sarcomas. There is no standard therapy for the patients with advanced CDS, and therapeutic development is needed. We evaluated preclinical efficacy of trastuzumab deruxtecan (T-DXd), a humanized monoclonal HER2-targeting antibody conjugated to a topoisomerase 1 inhibitor, DXd, in patient-derived xenograft (PDX) models with CDS.

Methods: Patient-derived tumor tissue was transplanted into subcutaneous around the flank of female NOG mice, which were treated with vehicle or T-DXd (3 mg/kg, intravenous, Day0) when the mean tumor volume reached 200 mm3. Tumor volume was assessed twice weekly for 3 weeks to assess the efficacy of T-DXd.

Results: This study included 3 CDS-derived PDXs. HER2 expression was low in one PDX and not expressed in two PDXs. One PDX was established from a specimen at initial diagnosis, two were established from specimens after prior-chemotherapy. T-DXd demonstrated significant tumor growth delay compared to vehicle in all PDX models investigated. One PDX with no efficacy was HER2-negative and had a treatment history of topoisomerase I inhibitor. In contrast, PDX of HER2-negative topoisomerase I inhibitor-resistant Ewing sarcoma was also administered T-DXd under the same conditions and was found to be refractory.

Conclusion: The present study showed that a therapeutic potential of T-DXd in CDS patients, including HER2-negative.

Citation Format: Yuki Kojima, Shigehiro Yagishita, Kazuki Sudo, Tatsunori Shimoi, Shintaro Iwata, Shun-ichi Watanabe, Chitose Ogawa, Akihiko Yoshida, Yasushi Yatabe, Kan Yonemori, Akinobu Hamada. Trastuzumab deruxtecan, antibody-drug conjugate targeting HER2, effectively inhibits growth of patient-derived xenograft model with CIC-rearranged sarcoma. [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 3995.

Frequent CD30 Expression in an Emerging Group of Mesenchymal Tumors With NTRK, BRAF, RAF1, or RET Fusions

Neurotrophic tyrosine receptor kinase (NTRK) fusions define infantile fibrosarcomas in young children and NTRK-rearranged spindle-cell tumors in older children and adults, which share characteristic spindle-cell histology and CD34 or S100 protein expression. Similar phenotypes were identified in tumors with BRAF, RAF1, or RET fusions, suggesting a unifying concept of "spindle-cell tumors with kinase gene fusions." In this study, we investigated CD30 expression in 38 mesenchymal tumors with kinase gene fusions using immunohistochemistry. CD30 was expressed in 15 of 22 NTRK-rearranged tumors and 12 of 16 tumors with BRAF, RAF1, or RET fusions. In total, CD30 was expressed in 27 of the 38 tumors (71%), with >50% CD30-positive cells in 21 tumors and predominantly moderate or strong staining in 24 tumors. CD34 and S100 protein were also expressed in 71% and 69% of the tumors, respectively. In contrast, CD30 was significantly less frequently expressed in other mesenchymal tumor types that histologically mimic kinase fusion-positive tumors (9 of 150 tumors, 6%), of which none showed >50% or predominantly strong staining. Among these mimicking tumors, malignant peripheral nerve sheath tumors occasionally (30%) expressed CD30, albeit in a weak focal manner in most positive cases. CD30 was also expressed in 3 of 15 separately analyzed ALK- or ROS1-positive inflammatory myofibroblastic tumors. Frequent expression of CD30 enhances the shared phenotype of spindle-cell tumors with NTRK and other kinase gene fusions, and its sensitivity seems similar to that of CD34 and S100 protein. Although moderate sensitivity hampers its use as a screening tool, CD30 expression could be valuable to rapidly identify high-yield candidates for molecular workup, particularly in communities that lack routine genetic analysis and/or for tumors with BRAF, RAF1, or RET fusions.

A case of vasculogenic mesenchymal tumor in the mediastinum: whole-exome sequencing reveals origin from pre-existing germ cell tumor

Vasculogenic mesenchymal tumor (VMT), a primitive mesenchymal neoplasm enriched by various-sized atypical vessels, is a new entity that develops in mediastinal germ cell tumors (GCTs) with yolk sac tumor (YST) components after chemotherapy. Notably, patients with VMT in the residual GCT have increased risk of developing sarcomas or hematopoietic malignancies. Here, we report a late-teenage male patient with residual teratoma and high-grade VMT after chemotherapy for a mediastinal mixed GCT, including YST. Whole-exome sequencing revealed biallelic inactivation of TP53 and extensive copy number alterations that suggested whole-genome doubling. The biopsy tissue of the mixed GCT before chemotherapy exhibited overlapping genetic alterations to those in the VMT. Immunohistochemical analyses of the VMT showed that the abnormal vessels were positive for cytokeratin, glypican 3, EZH2, and IMP3. The findings that VMT inherits the genetic alterations of pre-existing mixed GCT and exhibits a partly YST-like immunophenotype might contribute to its clinical aggressiveness.

Molecular pathology quality control in Southeast Asia: Results of a Multiregional Quality Assurance Study from MASTER KEY Asia

Tissue specimen quality assurance is a major issue of precision medicine for rare cancers. However, the laboratory standards and quality of pathological specimens prepared in Asian hospitals remain unknown. To understand the methods in Southeast Asian oncology hospitals and to clarify how pre-analytics affect the quality of formalin-fixed paraffin-embedded (FFPE) specimens, a questionnaire surveying pre-analytical procedures (Part I), quality assessment of immunohistochemistry staining (IHC) and DNA/RNA extracted from the representative FFPE specimen from each hospital (Part II), and quality of DNA/RNA extracted from FFPE of rare cancer patients for genomic sequencing (Part III), were conducted. Quality measurements for DNA/RNA included ΔΔCt, DV200, and cDNA yield. Six major cancer hospitals from Malaysia, Philippines, and Vietnam participated. One hospital showed unacceptable quality for the DNA/RNA assessment, but improved by revising laboratory procedures. Only 57% (n=73) of the 128 rare cancer patients' specimens met both DNA and RNA quality criteria for Next-Generation Sequencing. Median DV200 was 80.7% and 64.3% for qualified and failed RNA, respectively. Median ΔΔCt was 1.25 for qualified and 4.89 for failed DNA. Longer storage period was significantly associated with poor DNA (fail:qualify = 1579:321 days, p<0.001) and RNA (fail:qualify = 1070:280 days, p<0.001). After improvement of pre-analytical factors, the qualification rate increased for hospitals A and E from 41.5% to 70.5% and 62.5% to 86%, respectively. This is the first report to elucidate the pre-analytical laboratory procedures of main Southeast Asian oncology hospitals. An external quality assessment program may improve factors associated with tumor FFPE specimen quality.

Feasibility and effectiveness of segmentectomy versus wedge resection for clinical stage I non-small-cell lung cancer

OBJECTIVES

With recent improvements in surgical techniques for segmentectomy, we hypothesized that segmentectomy is feasible and more effective than wedge resection for non-small-cell lung cancer (NSCLC). We compared perioperative and oncological outcomes for segmentectomy and wedge resection.

METHODS

We performed a retrospective analysis of 720 patients who underwent sublobar resection (segmentectomy, 479; wedge resection, 241) for clinical stage 0 or I NSCLC from January 2017 to June 2020. An adequate surgical margin was defined as a surgical margin distance of ≥2 cm or ≥ the total tumour size. Recurrence-free survival (RFS) was estimated using the Kaplan-Meier method for clinical stage IA.

RESULTS

There was no significant difference in the rate of major (grade ≥III) complications between segmentectomy (1.7%) and wedge resection (1.2%) (P = 0.76). The probability of obtaining adequate surgical margins was significantly higher with segmentectomy (71.4%) versus wedge resection (59.5%) (P = 0.002), and the difference was especially prominent for clinical stage IA2 (75.3% vs 56.9%; P = 0.012). Among patients with clinical stage IA, segmentectomy significantly improved the RFS compared with wedge resection (hazard ratio 2.7; 95% confidence interval 1.60-4.61; log-rank P < 0.001). Subgroup analysis based on the tumour status revealed that segmentectomy had a better RFS in clinical stage IA2 (P < 0.001) and in pure-solid tumours (P = 0.022) than wedge resection.

CONCLUSIONS

We demonstrate that segmentectomy is a feasible procedure with comparable safety outcomes and better surgical margins and cancer control than wedge resection, particularly for clinical stage IA2 NSCLC.

Impact of age for overall survival in head and neck sarcoma

The purpose to the present study is to research the association between age at surgery and survival outcomes of patients with sarcoma in head and neck. Twenty-six patients with head and neck sarcoma who underwent by surgery from 2003 to 2017 were enrolled in the present observation study. Patients who did not undergo chemotherapy were significantly older age at surgery by Mann-Whitney U test. Fifty-five was the cutoff age that predicted death by receiver operating curve analysis. Shorter survival rates of overall, disease-specific, local recurrence-free and disease-free were associated with older age by log-rank test. Age (≥55 years/<55 years) was correlated with shorter overall survival by multivariate analysis of Cox's proportional hazards model adjusting with chemotherapy (absence/presence). In conclusion, older age predicts worse overall survival in head and neck sarcoma.

Adjuvant Osimertinib vs. Placebo in Completely Resected Stage IA2-IA3 EGFR-Mutated NSCLC: ADAURA2

INTRODUCTION

Osimertinib is a third-generation, irreversible, oral epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) that potently and selectively inhibits both EGFR-TKI sensitizing and EGFR T790M resistance mutations, with demonstrated efficacy in EGFR mutation-positive (EGFRm) non-small cell lung cancer (NSCLC), including central nervous system (CNS) metastases. Here we present the rationale and study design for ADAURA2 (NCT05120349), which will evaluate adjuvant osimertinib vs. placebo in patients with stage IA2-IA3 EGFRm NSCLC, following complete tumor resection.

PATIENTS AND METHODS

ADAURA2 is a phase III, global, randomized, double-blind, placebo-controlled study. Patients will be adults aged ≥18 years with resected primary nonsquamous NSCLC stage IA2 or IA3 and central confirmation of an EGFR exon 19 deletion or L858R mutation. Patients will be stratified by pathologic risk of disease recurrence (high vs. low), EGFR mutation type (exon 19 deletion vs. L858R) and race (Chinese Asian vs. non-Chinese Asian vs. non-Asian), and randomized 1:1 to receive osimertinib 80 mg once daily (QD) or placebo QD until disease recurrence, treatment discontinuation, or a maximum treatment duration of 3 years. The primary endpoint of this study is disease-free survival (DFS) in the high-risk stratum. Secondary endpoints include DFS in the overall population, overall survival, CNS DFS, and safety. Health-related quality of life and pharmacokinetics will also be evaluated.

RESULTS

Study enrolment began in February 2022 and interim results of the primary endpoint are expected in August 2027.

Real-world study of next-generation sequencing diagnostic biomarker testing for patients with lung cancer in Japan

Our previous real-world studies raised concerns that sequential biomarker testing may lead to increased time to treatment when compared with simultaneous single biomarker testing. The Oncomine Dx target test (ODxTT), a next-generation sequencing-based multiplex biomarker panel test approved in Japan in 2019, is expected to improve time to treatment due to changes in testing methods. This retrospective observational study examined data claims for reimbursement submitted for patients with lung cancer in Japan between June 1, 2019, and March 31, 2020. To evaluate the change in testing prevalence over time and associated improvements in time to treatment, descriptive statistics were used to characterize biomarker testing patterns and rates and evaluate the time to treatment in the time following the approval of ODxTT considering transitions over time during the evaluation period. EGFR and programmed death ligand 1 (PD-L1) were the most tested biomarkers in overall single and simultaneous single testing in the 6177 patients in this study. Individual single biomarker testing gradually decreased over time, except testing for PD-L1, which remained constant. The use of ODxTT gradually increased in this period. Time to treatment decreased from 29 to 22 days with ODxTT, in contrast to single biomarker tests (median 21-23 days overall). These results indicate that biomarker testing frequency changed in Japanese clinical practice during the study and that the use of ODxTT has increased over time, which potentially contributed to the shortening of time to treatment.

Keratin-positive fibrotic extraskeletal myxoid chondrosarcoma: a close mimic of myoepithelial tumour

AIMS

Extraskeletal myxoid chondrosarcoma (EMC) is a rare form of adult sarcoma with distinct histology and NR4A3 gene fusion. Immunohistochemically, EMCs are variably positive for S100 protein and neuroendocrine markers. Unlike histologically similar soft-tissue myoepithelial tumours, keratin expression is rare. Prompted by two recent EMC cases with diffuse keratin expression, we investigated the expression of epithelial markers in a molecularly confirmed cohort of EMC and identified two additional similar cases.

METHODS AND RESULTS

Four keratin-positive EMCs occurred in one man and three women aged 46-59 years. All tumours displayed nonclassic histology with prominent stromal fibrosis, and keratin AE1/AE3 was expressed either diffusely (N = 2) or focally (N = 2). In one tumour, keratin expression was limited to the sclerotic area. All tumours coexpressed epithelial membrane antigen and two additionally expressed S100 protein or glial fibrillary acidic protein. All tumours harboured NR4A3 fusions, including TAF15::NR4A3 (N = 1) and EWSR1::NR4A3 (N = 3). Two cases were initially considered as most consistent with myoepithelial tumours based on widespread stromal fibrosis and keratin expression. DNA methylation analysis classified two tumours tested as EMCs.

CONCLUSIONS

We identified a small subset of EMCs characterised by keratin expression and prominent stromal fibrosis. This histological pattern must be recognised in the differential diagnosis of myoepithelial tumours because misclassification may lead to the erroneous prediction of tumour behaviour and may alter patient management. NR4A3 genetic analysis should be considered even in the face of keratin expression and prominent stromal fibrosis.

Long-Term Prognosis and Prognostic Indicators of Stage IA Lung Adenocarcinoma

BACKGROUND

The 8th edition of the TNM stage classification of lung cancer was developed based on an evaluation of the 5-year prognosis using an international database. Since recurrence after 5 years postoperatively is known to develop, the applicability of the stage classification beyond 5 years after treatment needs to be evaluated.

PATIENTS AND METHODS

Postoperative prognosis and prognostic indicators were analyzed using data for 648 patients of pathological stage IA adenocarcinoma, who underwent complete resection between 2007 and 2012.

RESULTS

The median age was 66 years (interquartile range 60-73 years), and the median follow-up duration was 100 months (interquartile range 70-116 months). Overall survival probabilities for pathological stage IA1, IA2, and IA3 patients were 100%, 96.3%, and 91.5% at 5 postoperative years, and 94.2%, 89.8%, and 83.5% at 10 postoperative years, respectively (IA1 vs IA2: p = 0.05; IA2 vs IA3: p = 0.05). Multivariate analysis for overall survival of patients who survived without recurrence for 5 postoperative years revealed that age (hazard ratio 3.21, p = 0.02) was the only factor that was significantly associated with long-term survival. Stage classification (IA1, IA2, or IA3) was not an associated factor. The incidence of secondary primary lung cancer continued to increase, resulting in an estimated probability of 8.6% at 10 postoperative years.

CONCLUSIONS

For patients who survived without recurrence for 5 postoperative years, age, not stage classification, was associated with survival thereafter. The long-term follow-up strategy does not need to be modified according to the stage classification, and screening for secondary primary lung cancer should be considered.

Radiological precursor lesions of lung squamous cell carcinoma: Early progression patterns and divergent volume doubling time between hilar and peripheral zones

OBJECTIVES

This study investigated the early progression patterns of lung squamous cell carcinoma (SqCC) on computed tomography (CT) images.

MATERIALS AND METHODS

In total, 65 patients with SqCC who underwent surgical resection and two CT scans separated by an interval of at least 6 months were enrolled. We categorized the findings of the initial and at-diagnosis CT images into five patterns as previously reported. The volume doubling time (VDT) was calculated for measurable lesions.

RESULTS

A single nodule pattern on CT images at-diagnosis was most common in 56 (86.2 %) patients, in line with practical clinical findings. However, the patterns were diverse in the initial images, with 28 (43.1 %) patients displaying atypical findings, including multiple nodules (3.1 %), endobronchial lesions (20.0 %), subsolid nodules (10.8 %), and cyst wall thickening (9.2 %). All endobronchial lesions were located in the central/middle zone of the lung field, whereas lesions presented as multiple nodules, subsolid nodules, and cyst wall thickening were predominantly observed in the peripheral zone. The differences in the developed zones were reflected in the median VDT, and the tumors with an initial endobronchial pattern had a significantly shorter VDT than those with a subsolid nodule pattern (median: 140 days vs 276 days, p < 0.001).

CONCLUSIONS

Lung SqCC initiated with various CT image patterns, although most tumors ultimately developed a single nodule pattern by diagnosis. The initial CT image patterns differed between the hilar and peripheral zones, suggesting a difference in the progression scheme, which was also supported by differences in VDT.

Fine-needle biopsy with 19G needle is effective in combination with endoscopic ultrasound-guided tissue acquisition for genomic profiling of unresectable pancreatic cancer

OBJECTIVES

Comprehensive genomic profiling (CGP) has been approved in Japan since June 2019, enabling mutation-specific therapy. Although tissue sampling via endoscopic ultrasound-guided tissue acquisition (EUS-TA) is standard in pancreatic cancer, reports on obtaining appropriate samples for CGP, especially for the OncoGuide NCC Oncopanel System (NOP) and FoundationOne CDx (FOne), are lacking. Therefore, we investigated the success rate and factors related to appropriate EUS-TA sampling for CGP analysis suitability in unresectable pancreatic ductal adenocarcinoma (UR-PDAC).

METHODS

Participants comprised 150 UR-PDAC patients who underwent EUS-TA and tumor sample evaluation for CGP analysis suitability between June 2019 and December 2021. The proportion of patients meeting the criteria was evaluated considering tumor size, puncture lesion, presence of metastasis, type and size of puncture needle, suction method, number of punctures, and puncture route.

RESULTS

In total, 39.2% (60/153) of samples met NOP analysis suitability criteria and 0% met FOne analysis suitability criteria. The suitability rate was significantly higher with 19G fine-needle biopsy (FNB) (56.0%; 42/75) than with 22G FNB (32.6%; 14/43) and 22G fine-needle aspiration (11.4%; 4/35). Nineteen-gauge needle (odds ratio [OR] 2.53; 95% confidence interval [CI] 1.15-5.57; P = 0.021) and FNB (OR 3.57; 95% CI 1.05-12.20; P = 0.041) were independent factors contributing to NOP analysis suitability. Among 30 patients who underwent actual NOP analysis, the analysis success rate was 100% (30/30).

CONCLUSION

In sample collection via EUS-TA, 19G and FNB needles contribute to NOP analysis suitability.

Defining Morphologic Features of Invasion in Pulmonary Nonmucinous Adenocarcinoma With Lepidic Growth: A Proposal by the International Association for the Study of Lung Cancer Pathology Committee

INTRODUCTION

Since the eight edition of the Union for International Cancer Control and American Joint Committee on Cancer TNM classification system, the primary tumor pT stage is determined on the basis of presence and size of the invasive components. The aim of this study was to identify histologic features in tumors with lepidic growth pattern which may be used to establish criteria for distinguishing invasive from noninvasive areas.

METHODS

A Delphi approach was used with two rounds of blinded anonymized analysis of resected nonmucinous lung adenocarcinoma cases with presumed invasive and noninvasive components, followed by one round of reviewer de-anonymized and unblinded review of cases with known outcomes. A digital pathology platform was used for measuring total tumor size and invasive tumor size.

RESULTS

The mean coefficient of variation for measuring total tumor size and tumor invasive size was 6.9% (range: 1.7%-22.3%) and 54% (range: 14.7%-155%), respectively, with substantial variations in interpretation of the size and location of invasion among pathologists. Following the presentation of the results and further discussion among members at large of the International Association for the Study of Lung Cancer Pathology Committee, extensive epithelial proliferation (EEP) in areas of collapsed lepidic growth pattern is recognized as a feature likely to be associated with invasive growth. The EEP is characterized by multilayered luminal epithelial cell growth, usually with high-grade cytologic features in several alveolar spaces.

CONCLUSIONS

Collapsed alveoli and transition zones with EEP were identified by the Delphi process as morphologic features that were a source of interobserver variability. Definition criteria for collapse and EEP are proposed to improve reproducibility of invasion measurement.

Asian Thoracic Oncology Research Group (ATORG) Expert Consensus Statement on MET Alterations in NSCLC: Diagnostic and Therapeutic Considerations

Non-small cell lung cancer (NSCLC) is a heterogeneous disease, with many oncogenic driver mutations, including de novo mutations in the Mesenchymal Epithelial Transition (MET) gene (specifically in Exon 14 [ex14]), that lead to tumourigenesis. Acquired alterations in the MET gene, specifically MET amplification is also associated with the development of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) resistance in patients with EGFR-mutant NSCLC. Although MET has become an actionable biomarker with the availability of MET-specific inhibitors in selected countries, there is differential accessibility to diagnostic platforms and targeted therapies across countries in Asia-Pacific (APAC). The Asian Thoracic Oncology Research Group (ATORG), an interdisciplinary group of experts from Australia, Hong Kong, Japan, Korea, Mainland China, Malaysia, the Philippines, Singapore, Taiwan, Thailand and Vietnam, discussed testing for MET alterations and considerations for using MET-specific inhibitors at a consensus meeting in January 2022, and in subsequent offline consultation. Consensus recommendations are provided by the ATORG group to address the unmet need for standardised approaches to diagnosing MET alterations in NSCLC and for using these therapies. MET inhibitors may be considered for first-line or second or subsequent lines of treatment for patients with advanced and metastatic NSCLC harbouring MET ex14 skipping mutations; MET ex14 testing is preferred within multi-gene panels for detecting targetable driver mutations in NSCLC. For patients with EGFR-mutant NSCLC and MET amplification leading to EGFR TKI resistance, enrolment in combination trials of EGFR TKIs and MET inhibitors is encouraged.

Proportion of unresectable pancreatic cancer specimens obtained by endoscopic ultrasound-guided tissue acquisition meeting the OncoGuide™ NCC Oncopanel System analysis suitability criteria: a single-arm, phase II clinical trial

BACKGROUND

There are limited studies on the results of comprehensive genomic profiling testing for pancreatic cancer tissue specimens by endoscopic ultrasound-guided tissue acquisition (EUS-TA). This study aimed to evaluate the proportion of specimens obtained by EUS-TA using a 19-gauge (G) fine-needle biopsy (FNB) needle for unresectable pancreatic cancer (UR-PC) that met the OncoGuide^™ NCC Oncopanel System (NOP) analysis suitability criteria.

METHODS

In this single-arm, prospective, phase II study, EUS-TA was performed using a 19G FNB biopsy needle in patients with suspected UR-PC based on a contrast-enhanced computed tomography scan. The primary endpoint was the proportion of patients who met the NOP analysis suitability criteria, with a threshold, expected value, α-error, and power of 40%, 70%, 0.025, and 0.9, respectively, and the planned number of enrolled patients was 33. The NOP analysis suitability criteria were defined as tumor cell content ≥ 20% and tissue size ≥ 4 mm².

RESULTS

Thirty-three patients were enrolled. The procedural success rate was 100%, and the cytodiagnosis of class V was observed in all patients. The proportion of patients meeting the NOP analysis suitability criteria was 63.6% (95% CI 47.22-80.05), which satisfied the predefined criteria to be considered valid. Adverse events occurred in 9.0% of the patients.

CONCLUSIONS

The proportion of patients with UR-PC who met the NOP analysis suitability criteria for EUS-TA using a 19G FNB needle was effective for achieving the primary endpoint, making it a valid test method. Adverse events occurred at a higher rate than that previously reported.

Insulinoma-associated-1 (INSM1) expression in thymic squamous cell carcinoma

Thymic squamous cell carcinoma (TSC) presents distinct immunohistochemical features with its expression of CD5 and CD117, both of which are rarely expressed in squamous cell carcinoma in other organs. We found insulinoma-associated-1 (INSM1) expression in some TSCs; thus, a series of thymic tumors were examined retrospectively. Using surgically resected thymic tumors (TSC, n = 35; thymic atypical carcinoid [TAC], n = 4; and thymoma, n = 112) and non-neoplastic thymic tissue (n = 26), we evaluated immunohistochemically the expressions of INSM1, ASCL1, SOX2, NE markers (synaptophysin, chromogranin A, and CD56), and conventional TSC markers (CD5 and CD117). INSM1 was expressed in 22 TSCs (63%), whereas the positive frequencies of synaptophysin, chromogranin A, and CD56 were limited to 13, 10, and 1 cases, respectively. The discordance was highly contrasted with concordantly positive TACs. INSM1 and NE makers were rarely expressed in thymomas. INSM1 expression in TSCs was also associated with CD5 expression, which was significantly less frequent in INSM1-negative TSCs. INSM1, ASCL1, and SOX2 expressions were correlated with one another, but none of the single transcription factors or their combinations is associated with NE expression. The non-neoplastic medullary thymic epithelium was dispersedly positive for INSM1, particularly around Hassall's corpuscles. Despite positive INSM1, a significant decrease in the frequency of NE maker expression may present as a diagnostic pitfall in TSCs. Furthermore, the discordance, which was inherent in the non-neoplastic thymic epithelium, might be a characteristic feature in TSCs.