Comparative Study of Indocyanine Green Intravenous Injection and the Inflation-Deflation Method for Assessing Resection Margins in Segmentectomy for Lung Cancer: A Single-Center Retrospective Study

Background

The inflation-deflation (ID) method has long been the standard for intraoperative margin assessment in segmentectomy. However, with advancements in vision technology, the use of near-infrared mapping with indocyanine green (ICG) has become increasingly common. This study was conducted to compare the perioperative outcomes and resection margins achieved using these methods.

Methods

This retrospective study included patients who underwent direct segmentectomy for clinical stage I lung cancer between January 2018 and September 2022. We compared perioperative factors, including bronchial and parenchymal resection margins, according to the margin assessment method and the type of segmentectomy performed. Since the ICG approach was adopted in April 2021, we also examined a recent subgroup of patients treated from then onward.

Results

A total of 319 segmentectomies were performed. ID and ICG were utilized for 261 (81.8%) and 58 (18.2%) patients, respectively. Following April 2021, 61 patients (51.3%) were treated with ID, while 58 (48.7%) received ICG. We observed no significant difference in resection margins between ID and ICG for bronchial (2.7 cm vs. 2.3 cm, p=0.07) or parenchymal (2.5 cm vs. 2.3 cm, p=0.46) margins. Additionally, the length of hospitalization and the complication rate were comparable between groups. Analysis of the recent subgroup confirmed these findings, showing no significant differences in resection margins (bronchial: 2.6 cm vs. 2.3 cm, p=0.25; parenchymal: 2.4 cm vs. 2.3 cm, p=0.75), length of hospitalization, or complication rate.

Conclusion

The perioperative outcomes and resection margins achieved using ID and ICG were comparable, suggesting that both methods can safely guide segmentectomy procedures.

Clinical Utility of a CT-based AI Prognostic Model for Segmentectomy in Non-Small Cell Lung Cancer

Background Currently, no tool exists for risk stratification in patients undergoing segmentectomy for non-small cell lung cancer (NSCLC). Purpose To develop and validate a deep learning (DL) prognostic model using preoperative CT scans and clinical and radiologic information for risk stratification in patients with clinical stage IA NSCLC undergoing segmentectomy. Materials and Methods In this single-center retrospective study, transfer learning of a pretrained model was performed for survival prediction in patients with clinical stage IA NSCLC who underwent lobectomy from January 2008 to March 2017. The internal set was divided into training, validation, and testing sets based on the assignments from the pretraining set. The model was tested on an independent test set of patients with clinical stage IA NSCLC who underwent segmentectomy from January 2010 to December 2017. Its prognostic performance was analyzed using the time-dependent area under the receiver operating characteristic curve (AUC), sensitivity, and specificity for freedom from recurrence (FFR) at 2 and 4 years and lung cancer-specific survival and overall survival at 4 and 6 years. The model sensitivity and specificity were compared with those of the Japan Clinical Oncology Group (JCOG) eligibility criteria for sublobar resection. Results The pretraining set included 1756 patients. Transfer learning was performed in an internal set of 730 patients (median age, 63 years [IQR, 56-70 years]; 366 male), and the segmentectomy test set included 222 patients (median age, 65 years [IQR, 58-71 years]; 114 male). The model performance for 2-year FFR was as follows: AUC, 0.86 (95% CI: 0.76, 0.96); sensitivity, 87.4% (7.17 of 8.21 patients; 95% CI: 59.4, 100); and specificity, 66.7% (136 of 204 patients; 95% CI: 60.2, 72.8). The model showed higher sensitivity for FFR than the JCOG criteria (87.4% vs 37.6% [3.08 of 8.21 patients], P = .02), with similar specificity. Conclusion The CT-based DL model identified patients at high risk among those with clinical stage IA NSCLC who underwent segmentectomy, outperforming the JCOG criteria. © RSNA, 2024 Supplemental material is available for this article.

Safety of lung resection surgery after severe acute respiratory syndrome coronavirus 2 infection in the post-vaccination era

OBJECTIVES

To investigate the postoperative outcomes of lung resection in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and determine the optimal timing of surgery.

METHODS

This retrospective, single-centre cohort study included patients who underwent lung resection between June 2021 and June 2022. Patients were divided into the coronavirus disease 2019 (COVID-19) and non-COVID-19 groups based on their preoperative SARS-CoV-2 infection history, and postoperative outcomes were compared. Logistic regression analysis was conducted to identify the risk factors of complications after lung resection surgery.

RESULTS

In total, 1194 patients were enrolled, of whom, 79 had a history of SARS-CoV-2 infection. In the COVID-19 group, 66 patients (90.4%) had received at least 1 vaccination dose. The average interval between infection and surgery was 67 days, with no significant impact on postoperative outcomes. Regarding postoperative outcomes, there were no significant differences in major complication rate (6.3% vs 5.4%, P = 0.613), respiratory complication rate (19.0% vs 12.2%, P = 0.079) or length of stays (4.9 ± 3.4 vs 5.0 ± 5.6, P = 0.992) between the 2 groups. Multivariate logistic regression analysis revealed that age, male sex, poor pulmonary function test, open surgery and extensive lung resection were risk factors for postoperative complications, while preoperative COVID-19 infection status was not a statistically significant risk factor.

CONCLUSIONS

In the post-vaccination era, lung resection surgery can be safely performed shortly after SARS-CoV-2 infection, even within 4 weeks of infection.

Preoperative evaluation of mediastinal lymph nodes in non-small cell lung cancer using [68Ga]FAPI-46 PET/CT: a prospective pilot study

PURPOSE

Mediastinal nodal staging is crucial for surgical candidate selection in non-small cell lung cancer (NSCLC), but conventional imaging has limitations often necessitating invasive staging. We investigated the additive clinical value of fibroblast activation protein inhibitor (FAPI) PET/CT, an imaging technique targeting fibroblast activation protein, for mediastinal nodal staging of NSCLC.

METHODS

In this prospective pilot study, we enrolled patients scheduled for surgical resection of NSCLC based on specific criteria designed to align with indications for invasive staging procedures. Patients were included when meeting at least one of the following: (1) presence of FDG-positive N2 lymph nodes, (2) clinical N1 stage, (3) central tumor location or tumor diameter of ≥ 3 cm, and (4) adenocarcinoma exhibiting high FDG uptake. [68Ga]FAPI-46 PET/CT was performed before surgery after a staging workup including [18F]FDG PET/CT. The diagnostic accuracy of [68Ga]FAPI-46 PET/CT for "N2" nodes was assessed through per-patient visual assessment and per-station quantitative analysis using histopathologic results as reference standards.

RESULTS

Twenty-three patients with 75 nodal stations were analyzed. Histopathologic examination confirmed that nine patients (39.1%) were N2-positive. In per-patient assessment, [68Ga]FAPI-46 PET/CT successfully identified metastasis in eight patients (sensitivity 0.89 (0.52-1.00)), upstaging three patients compared to [18F]FDG PET/CT. [18F]FDG PET/CT detected FDG-avid nodes in six (42.8%) of 14 N2-negative patients. Among them, five were considered non-metastatic based on calcification and distribution pattern, and one was considered metastatic. In contrast, [68Ga]FAPI-46 PET/CT correctly identified all non-metastatic patients solely based on tracer avidity. In per-station analysis, [68Ga]FAPI-46 PET/CT discriminated metastasis more effectively compared to [18F]FDG PET/CT-based (AUC of ROC curve 0.96 (0.88-0.99) vs. 0.68 (0.56-0.78), P < 0.001).

CONCLUSION

[68Ga]FAPI-46 PET/CT holds promise as an imaging tool for preoperative mediastinal nodal staging in NSCLC, with improved sensitivity and the potential to reduce false-positive results, optimizing the need for invasive staging procedures.

Optimal resection strategies for small-size lung cancer: Is a wedge enough? Is lobectomy too much?

Recently published large multicenter prospective clinical trials have demonstrated that sublobar resection is noninferior to lobectomy, the traditional treatment of choice, for peripherally located early-stage lung cancer. Most clinical trials and several retrospective studies published to date have used the consolidation-to-tumor ratio to define the indication for sublobar resection, as it is well known that the size of the solid portion seen on high-resolution computed tomography is highly correlated with pathologic invasiveness. However, it is difficult to accurately predict pathologic features that may increase the risk of locoregional recurrence, such as specific adenocarcinoma subtypes or spread through air spaces, based on imaging characteristics alone, and the location of the nodule also should be considered one of the important factors in obtaining an adequate parenchymal resection margin. In this article, we summarize the results of the most recently published clinical trials related to sublobar resection and discuss various factors that should be considered for optimal candidate selection for sublobar resection.

The Prognostic Value of Oligo-Recurrence Following Esophagectomy for Esophageal Cancer

Background

The concept of oligo-recurrence has not been generally applied in esophageal cancer. This study aimed to determine the prognostic significance of the number of recurrences in esophageal cancer.

Methods

Patients with squamous cell carcinoma who underwent curative esophagectomy with R0 or R1 resection and who experienced a confirmed recurrence were included. The study included 321 eligible participants from March 2001 to December 2019. The relationship between the number of recurrences and post-recurrence survival was investigated.

Results

The mean age was 63.8±8.1 years, and the majority of the participants (97.5%) were men. The median time to recurrence was 10.7 months, and the median survival time after recurrence was 8.8 months. Multiple recurrences with simultaneous local, regional, and distant locations were common (38%). In terms of the number of recurrences, single recurrences were the most common (38.3%) and had the best post-recurrence survival rate (median, 17.1 months; p<0.001). Patients with 2 or 3 recurrences showed equivalent survival to each other and longer survival than those with 4 or more (median, 9.4 months; p<0.001). In the multivariable analysis, the significant predictors of post-recurrence survival were body mass index, minimally invasive esophagectomy, N stage, R0 resection, post-recurrence treatment, and the number of recurrences (p<0.05).

Conclusion

After esophagectomy, the number of recurrences was the most significant risk factor influencing post-recurrence survival in patients with esophageal cancer. In esophageal cancer, oligo-recurrence can be defined as a recurrence with three or fewer metastases. More intensive treatment might be recommended if oligo-recurrence occurs.

Correlation Between Pain Intensity and Quality of Recovery After Video-Assisted Thoracic Surgery for Lung Cancer Resection

Purpose

The Quality of Recovery-15 (QoR-15) questionnaire provides a multifaceted assessment of postoperative recovery, and the resulting score is recommended as an endpoint in clinical studies focused on postoperative pain. We aimed to investigate the correlation between the QoR-15 score and postoperative pain intensity in surgical patients.

Patients and Methods

Adult patients who underwent video-assisted thoracoscopic surgery (VATS) for lung cancer resection and were enrolled in a prospective registry or in a previous prospective study were included in this study. Baseline and perioperative data, including the results of assessment using the Korean version of the QoR-15 (QoR-15K) questionnaire at 48 hours postoperatively, were collected from the database. Correlations between the QoR-15K total score, questionnaire dimensions, and postoperative pain intensity at 48 hours postoperatively were determined using the Spearman correlation coefficient (ρ).

Results

We analyzed a total of 137 eligible patients. Significant negative correlations were noted between the QoR-15K total score and pain intensity at rest (ρ = -0.45, 95% confidence interval [CI]: -0.57 - -0.31, P < 0.001) and during coughing (ρ = -0.55, 95% CI: -0.65 - -0.42, P < 0.001) at 48 hours postoperatively. The pain dimension and pain intensity at 48 hours postoperatively showed significant correlations with physical comfort, emotional state, and physical independence dimensions. Multivariable logistic regression revealed a significant negative association between the pain score at 24 hours postoperatively and good or excellent postoperative recovery.

Conclusion

The results support the impact of postoperative pain on the overall postoperative quality of recovery in patients who underwent VATS for lung cancer resection. Moreover, the QoR-15K score may be considered as a primary endpoint in clinical studies on postoperative pain control.

Artificial intelligence-powered spatial analysis of tumor-infiltrating lymphocytes as a biomarker in locally advanced unresectable thymic epithelial neoplasm: A single-center, retrospective, longitudinal cohort study

BACKGROUND

Thymic epithelial tumors (TET) are rare malignancies and lack well-defined biomarkers for neoadjuvant therapy. This study aimed to evaluate the clinical utility of artificial intelligence (AI)-powered tumor-infiltrating lymphocyte (TIL) analysis in TET.

METHODS

Patients initially diagnosed with unresectable thymoma or thymic carcinoma who underwent neoadjuvant therapy between January 2004 and December 2021 formed our study population. Hematoxylin and eosin-stained sections from the initial biopsy and surgery were analyzed using an AI-powered spatial TIL analyzer. Intratumoral TIL (iTIL) and stromal TIL (sTIL) were quantified and their immune phenotype (IP) was identified.

RESULTS

Thirty-five patients were included in this study. The proportion of patients with partial response to neoadjuvant therapy was higher in the group with nondesert IP in preneoadjuvant biopsy (63.6% vs. 17.6%, p = 0.038). A significant increase in both iTIL (median 22.18/mm2 vs. 340.69/mm2 , p < 0.001) and sTIL (median 175.19/mm2 vs. 531.02/mm2 , p = 0.004) was observed after neoadjuvant therapy. Patients with higher iTIL (>147/mm2 ) exhibited longer disease-free survival (median, 29 months vs. 12 months, p = 0.009) and overall survival (OS) (median, 62 months vs. 45 months, p = 0.002). Patients with higher sTIL (>232.1/mm2 ) exhibited longer OS (median 62 months vs. 30 months, p = 0.021).

CONCLUSIONS

Nondesert IP in initial biopsy was associated with a better response to neoadjuvant therapy. Increased infiltration of both iTIL and sTIL in surgical specimens were associated with longer OS in patients with TET who underwent resection followed by neoadjuvant therapy.

Infective Costochondritis after Augmentation Mammoplasty: A Rare Case Report and Review of the Literature

Silicone breast implant insertion is a commonly performed surgical procedure for breast augmentation or reconstruction. Among various postoperative complications, infection is one of the main causes of patient readmission and may ultimately require explantation. We report a case of infective costochondritis after augmentation mammoplasty, which has rarely been reported and is therefore difficult to diagnose. A 36-year-old female visited the clinic for persistent redness, pain, and purulent discharge around the left anteromedial chest, even after breast implant explantation. Magnetic resonance imaging showed abscess formation encircling the left fourth rib and intracartilaginous and bone marrow signal alteration at the left body of the sternum and left fourth rib. En bloc resection of partial rib and adjacent sternum were done and biopsy results confirmed infective costochondritis. Ten months postoperatively, the patient underwent chest wall reconstruction with an artificial bone graft and acellular dermal matrix. As shown in this case, early and aggressive surgical debridement of the infected costal cartilage and sternum should be performed for infective costochondritis. Furthermore, delayed chest wall reconstruction could significantly contribute to the quality of life.

Impact of supradiaphragmatic lymphadenectomy on the survival of patients in stage IVB ovarian cancer with thoracic lymph node metastasis

Introduction

To evaluate the survival impact of supradiaphragmatic lymphadenectomy as part of debulking surgery in stage IVB ovarian cancer with thoracic lymph node metastasis (LNM).

Methods

We retrospectively enrolled patients diagnosed with stage IVB ovarian, fallopian or primary peritoneal cancer between 2010 and 2020, carrying cardiophrenic, parasternal, anterior mediastinal or supraclavicular lymph nodes ≥5 mm on axial chest computed tomography. All tumors were classified into the abdominal (abdominal tumors and cardiophrenic lymph nodes) and supradiaphragmatic (parasternal, anterior mediastinal or supraclavicular lymph nodes) categories depending on the area involved. Residual tumors were classified into <5 vs ≥5 mm in the abdominal and supradiaphragmatic areas. Based on the site of recurrence, they were divided into abdominal, supradiaphragmatic and other areas.

Results

A total of 120 patients underwent primary debulking surgery (PDS, n=68) and interval debulking surgery after neoadjuvant chemotherapy (IDS/NAC, n=53). Residual tumors in the supradiaphragmatic area ≥5 mm adversely affected progression-free survival (PFS) and overall survival (OS) with marginal significance after PDS despite the lack of effect on survival after IDS/NAC (adjusted hazard ratios [HRs], 6.478 and 6.370; 95% confidence intervals [CIs], 2.224-18.864 and 0.953-42.598). Further, the size of residual tumors in the abdominal area measuring ≥5 mm diminished OS after IDS/NAC (adjusted HR, 9.330; 95% CIs, 1.386-62.800).

Conclusion

Supradiaphragmatic lymphadenectomy during PDS may improve survival in patients diagnosed with stage IVB ovarian cancer manifesting thoracic LNM. Further, suboptimal debulking surgery in the abdominal area may be associated with poor OS after IDS/NAC.

Trial registration

ClinicalTrials.gov (NCT05005650; https://clinicaltrials.gov/ct2/show/NCT05005650; first registration, 13/08/2021).Research Registry (Research Registry UIN, researchregistry7366; https://www.researchregistry.com/browse-the-registry#home/?view_2_search=researchregistry7366&view_2_page=1).

Thoracoscopic segmentectomy in children with congenital lung malformation

Congenital lung malformations (CLM) are most commonly treated with a pulmonary lobectomy. However, due to technological advancement, video-assisted thoracoscopic surgery (VATS) segmentectomy is becoming an attractive alternative to VATS lobectomy. This study aimed to evaluate the safety, feasibility, and efficacy of VATS segmentectomy as a lung parenchyma-saving strategy in children with CLM. A retrospective analysis was performed on 85 children, for whom VATS segmentectomy was tried for CLM between January 2010 and July 2020. We compared the surgical outcomes of VATS segmentectomy with the outcomes of 465 patients who underwent VATS lobectomy. Eighty-four patients received VATS segmentectomy and thoracotomy conversion was necessary for one patient for CLM. The mean age was 3.2 ± 2.5 (range 1.2-11.6) years. The mean operative time was 91.4 ± 35.6 (range 40-200) minutes. The median duration of chest tube drainage was 1 (range 1-21) day, and the median length of postoperative hospital stay was 4 (range 3-23) days. There were no postoperative mortality and postoperative complications developed in 7 patients (8.2%), including persistent air leakage in 6 patients (7.1%) and postoperative pneumonia in 1 patient (1.2%). The median follow-up period was 33.5 (interquartile range 31-57) months and there were no patients requiring re-intervention or reoperation during the follow-up period. In the VATS segmentectomy group, the persistent air leakage rate was higher than in the VATS lobectomy group (7.1 vs. 1.1%, p = 0.003). Otherwise, postoperative outcomes were comparable between the two groups. VATS segmentectomy in children with CLM is a technically feasible alternative to VATS lobectomy with acceptable early and mid-term outcomes. However, the persistent air-leakage rate was higher in VATS segmentectomy.

99mTc-MAA accumulation within tumor in preoperative lung perfusion SPECT/CT associated with occult lymph node metastasis in patients with clinically N0 non-small cell lung cancer

BACKGROUND

^99mTc-MAA accumulation within the tumor representing pulmonary arterial perfusion, which is variable and may have a clinical significance. We evaluated the prognostic significance of ^99mTc-MAA distribution within the tumor in non-small cell lung cancer (NSCLC) patients in terms of detecting occult nodal metastasis and lymphovascular invasion, as well as predicting the recurrence-free survival (RFS).

METHODS

Two hundred thirty-nine NSCLC patients with clinical N0 status who underwent preoperative lung perfusion SPECT/CT were retrospectively evaluated and classified according to the visual grading of ^99mTc-MAA accumulation in the tumor. Visual grade was compared with the quantitative parameter, standardized tumor to lung ratio (TLR). The predictive value of ^99mTc-MAA accumulation with occult nodal metastasis, lymphovascular invasion, and RFS was assessed.

RESULTS

Eighty-nine (37.2%) patients showed ^99mTc-MAA accumulation and 150 (62.8%) patients showed the defect on ^99mTc-MAA SPECT/CT. Among the accumulation group, 45 (50.5%) were classified as grade 1, 40 (44.9%) were grade 2, and 4 (4.5%) were grade 3. TLR gradually and significantly increased from grade 0 (0.009 ± 0.005) to grade 1 (0.021 ± 0.005, P < 0.05) and to grade 2-3 (0.033 ± 0.013, P < 0.05). The following factors were significant predictors for occult nodal metastasis in univariate analysis: central location, histology different from adenocarcinoma, tumor size greater than 3 cm representing clinical T2 or higher, and the absence of ^99mTc-MAA accumulation within the tumor. Defect in the lung perfusion SPECT/CT remained significant at the multivariate analysis (Odd ratio 3.25, 95%CI [1.24 to 8.48], p = 0.016). With a median follow-up of 31.5 months, the RFS was significantly shorter in the defect group (p = 0.008). Univariate analysis revealed that cell type of non-adenocarcinoma, clinical stage II-III, pathologic stage II-III, age greater than 65 years, and the ^99mTc-MAA defect within tumor as significant predictors for shorter RFS. However, only the pathologic stage remained statistically significant, in multivariate analysis.

CONCLUSION

The absence of ^99mTc-MAA accumulation within the tumor in preoperative lung perfusion SPECT/CT represents an independent risk factor for occult nodal metastasis and is relevant as a poor prognostic factor in clinically N0 NSCLC patients. ^99mTc-MAA tumor distribution may serve as a new imaging biomarker reflecting tumor vasculatures and perfusion which can be associated with tumor biology and prognosis.

Abstract 2055: Prevalent focal amplification of oncogene in lung adenocarcinomas without canonical driver alterations

Lung adenocarcinoma (LADC) is the most common type of lung cancer and a leading cause of death worldwide. Typical oncogenes that drive LADCs when mutated (referred to as canonical drivers) include EGFR (30-60%), KRAS (10-30%), and fusion oncogenes (~10%) involving ALK, RET, and ROS1. However, approximately 30% of lung adenocarcinomas lack canonical drivers, implying unseen kinds of genomic alterations. Here, we explore alterations beyond the scope of canonical drivers in LADCs (referred to as non-canonical drivers) using large-scale whole-genome sequencing (WGS) of LADCs. We gathered total 183 WGS of LADCs, 138 of which were from our previous study (Lee et al. Cell. 2019) and 45 were newly sequenced from surgically resected LADCs. For raw data processing, we used a standard WGS analysis pipeline from read mapping to variant calling. Variant filtering and downstream analyses were performed using in-house scripts. Genomic variants analyzed in this study include single-base substitution (SBS), indel, structural variation (SV), and copy number variation (CNV). As a result, we found that 53 cases (29%) had no canonical drivers (ND group). Intriguingly, LADCs without canonical drivers had a contrasting genomic landscape compared to LADCs with canonical drivers (CD group). First, the point-mutation burden was ~3-fold higher in the ND group than in the CD group (52,500 vs. 17,900 for SNVs, p&lt;0.001). Mutational signature analysis revealed that these additional mutations are attributable mainly to tobacco smoking (by mutational signature SBS4) and APOBEC-mediated mutagenesis (SBS12 and SBS13) and that they are more enriched in the ND group (4,800 vs 2,600, p=0.03). Second, the ND group harbored more frequent focal amplifications. Recurrently amplified genes include TERT, IL7R, NKX2-1, CCND1, CCND3, CCNE1, and EGFR. The pattern of SVs suggest that the amplifications occurred through the formation of extra-chromosomal DNA involving multiple chromosomes or following chromothripsis. Overall, this study broadens our understanding of non-canonical drivers of LADCs. Similar analyses of thousands of cancers with clinical information of the patient will likely yield the functional impact of these driver mutations and may offer more opportunities for LADC treatment in the future.

Citation Format: Seongyeol Park, Joonoh Lim, Kijong Yi, Boram Yi, Ryul Kim, Jaemo Koo, Kwon Joong Na, Samina Park, In Kyu Park, Chang Hyun Kang, Jeong Seok Lee, Young Seok Ju, Young Tae Kim. Prevalent focal amplification of oncogene in lung adenocarcinomas without canonical driver alterations [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 2055.

Abstract 3138: Topological analysis of spatial transcriptomics reveals different spatial interaction patterns in tumor microenvironment of lung cancer

Background: As the tumor microenvironment (TME) consists of various cell types with complex spatial interaction, its spatial organization patterns affect response to immune-oncology treatment. Therefore, describing the spatial composition and interaction of cells in the tumor microenvironment (TME) is necessary. Here, we developed a tool, STopover, which adopts topological analysis in spatial transcriptomics to reveal cell-cell colocalization patterns in TME and capture the key components and niche of intercellular communication, and applied it to human lung cancer data.

Methods: The spatial colocalization pattern of pairs of features was defined using topological data analysis with Morse filtration. The spatial network of spatial gene expression data was generated for each sample and then the patterns were summarized as connected components (CCs) based on the spatial distance between unit tissue regions and the persistence of each CC. The global and local extent of spatial overlap of a feature pair was calculated as Jaccard indices between extracted CC pairs. We applied STopover to 11 barcode-based spatial transcriptomic data of human lung adenocarcinoma with different PD-L1 expressions. Spatial mapping of cell types in TME was performed by CellDART. In addition, image-based spatial transcriptomic data of lung cancer were also used to find key spatial molecular interactions in TME using STopover.

Results: First, STopover disclosed the distinct immune and stromal infiltration patterns in lung cancer tissues. Spatial colocalization of cancer cells and T-cells was heterogeneous and correlated with the immune-related markers such as MHC class I signature. The cancer types were clustered according to spatial colocalization patterns of various immune cells with cancer cells, which showed different infiltration patterns of immune cells. Moreover, STopover could estimate the top cell-cell interaction and emphasize the key locations based on the literature-supported ligand-receptor database.

Conclusion: STopover is expected to account for significant spatial cell interactions in tumor-immune and tumor-stromal components and could be utilized as a platform to decipher the mechanisms underlying immune-oncology treatment response.

Citation Format: Sungwoo Bae, Hyekyoung Lee, Kwon Joong Na, Dong Soo Lee, Hongyoon Choi, Young Tae Kim. Topological analysis of spatial transcriptomics reveals different spatial interaction patterns in tumor microenvironment of lung cancer [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 3138.

Risk Factors of Anastomosis Stricture After Esophagectomy and the Impact of Anastomosis Technique

BACKGROUND

Anastomosis complications after esophagectomy are related to postoperative survival and quality of life. This is a retrospective observational study to identify risk factors for anastomotic stricture after esophageal cancer surgery and the effect of different anastomosis techniques on stricture development.

METHODS

This study included 737 patients who underwent esophagectomy for esophageal cancer that used stomach conduits. Four types of anastomoses were used: manual sewing (n = 221, 30%), circular stapling (n = 172, 23%), hybrid linear stapling with a 45-mm stapler (HLS; n = 155, 21%), and triangular linear stapling with 60-mm staplers (TLS; n = 189, 26%). Multivariate analysis was performed to evaluate the risk factors for stricture.

RESULTS

Strictures that required endoscopic dilatation within 1 year after surgery occurred in 105 patients (14%), and 13% of the strictures were related to leakage. Multivariate analysis revealed that chronic obstructive pulmonary disease (hazard ratio [HR] 1.726, P = .017), leakage (HR 2.502, P = .015), and anastomosis techniques other than TLS (manual sewing: HR 9.588; circular stapling: HR 6.516; HLS HR 5.462, all P < .001) were significant risk factors for stricture. TLS significantly reduced the stricture rate (3.2%) compared with other techniques (manual sewing: 22.2%; circular stapling:, 14.5%; HLS: 16.1%; P < .001). Stricture rate was lower in the TLS group in patients without leakage (P < .001); however, the effect disappeared with leakage.

CONCLUSIONS

Anastomosis stricture occurred in 14% of esophagectomy patients. Chronic obstructive pulmonary disease, leakage, and anastomosis technique are risk factors for stricture. A large anastomosis area with the TLS technique using 60-mm length linear staplers prevented stricture, especially when leakage was not observed.

The Role of Adjuvant Therapy Following Surgical Resection of Small Cell Lung Cancer: A Multi-Center Study

PURPOSE

This multi-center, retrospective study was conducted to evaluate the long-term survival in patients who underwent surgical resection for small cell lung cancer (SCLC) and to identify the benefit of adjuvant therapy following surgery.

MATERIALS AND METHODS

The data of 213 patients who underwent surgical resection for SCLC at four institutions were retrospectively reviewed. Patients who received neoadjuvant therapy or an incomplete resection were excluded.

RESULTS

The mean patient age was 65.29±8.93 years, and 184 patients (86.4%) were male. Lobectomies and pneumonectomies were performed in 173 patients (81.2%), and 198 (93%) underwent systematic mediastinal lymph node dissections. Overall, 170 patients (79.8%) underwent adjuvant chemotherapy, 42 (19.7%) underwent radiotherapy to the mediastinum, and 23 (10.8%) underwent prophylactic cranial irradiation. The median follow-up period was 31.08 months (interquartile range, 13.79 to 64.52 months). The 5-year overall survival (OS) and disease-free survival were 53.4% and 46.9%, respectively. The 5-year OS significantly improved after adjuvant chemotherapy in all patients (57.4% vs. 40.3%, p=0.007), and the survival benefit of adjuvant chemotherapy was significant in patients with negative node pathology (70.8% vs. 39.7%, p=0.004). Adjuvant radiotherapy did not affect the 5-year OS (54.6% vs. 48.5%, p=0.458). Age (hazard ratio [HR], 1.032; p=0.017), node metastasis (HR, 2.190; p < 0.001), and adjuvant chemotherapy (HR, 0.558; p=0.019) were associated with OS.

CONCLUSION

Adjuvant chemotherapy after surgical resection in patients with SCLC improved the OS, though adjuvant radiotherapy to the mediastinum did not improve the survival or decrease the locoregional recurrence rate.

Relative infectivity of the SARS-CoV-2 Omicron variant in human alveolar cells

With the continuous emergence of highly transmissible SARS-CoV-2 variants, the comparison of their infectivity has become a critical issue for public health. However, a direct assessment of the viral characteristic has been challenging due to the lack of appropriate experimental models and efficient methods. Here, we integrated human alveolar organoids and single-cell transcriptome sequencing to facilitate the evaluation. In a proof-of-concept study with four highly transmissible SARS-CoV-2 variants, including GR (B.1.1.119), Alpha (B.1.1.7), Delta (B.1.617.2), and Omicron (BA.1), a rapid evaluation of the relative infectivity was possible. Our system demonstrates that the Omicron variant is 5- to 7-fold more infectious to human alveolar cells than the other SARS-CoV-2 variants at the initial stage of infection. To our knowledge, for the first time, this study measures the relative infectivity of the Omicron variant under multiple virus co-infection and provides new experimental procedures that can be applied to monitor emerging viral variants.

Remotely shared CT-derived presurgical understanding of lung cancer: A randomized trial

Shared decision‐making is imperative for patient‐and family‐centered care. However, gathering individuals in a single place was challenged by modern life and pandemic restrictions. This study conducted a 1:1 randomized trial to examine the feasibility of a CT‐derived 3D virtual explanation module for lung cancer to improve the understanding of patients and third parties in physically separate locations. We prospectively enrolled adults in whom elective surgical resection for lung cancer was planned at a single tertiary hospital in 2020. From presurgical CT scans, deep neural networks automatically segmented lung cancer, airway, pulmonary lobes, skin, and bony thorax. The segmented structures were subsequently transformed into an anonymized interactive 3D module which comprised a standardized scenario with explanatory texts. The intervention group received a link to the module on their smartphone before admission and could repeatedly access the link or transfer it to patients' third parties. A total of 33 and 29 patients were enrolled in the intervention and control arms. The understanding score did not statistically differ between the arms (mean difference, 0.7 [95% CI: −0.2, 1.5]; p = 0.13). However, 76% of patients in the intervention arm accessed the link, and patient median access count was 14. The link recipients of third parties had comparable understanding scores to the patients (mean difference, −0.2 [95% CI: −1.9, 1.5]; p = 1.00), indicating that the understanding could be shared remotely with patients and patients’ third parties. In conclusion, it was feasible that people physically separated from patients obtained a comparable understanding of lung cancer surgery using the patient's CT‐derived 3D virtual explanation module.

Effect of Continuous Infusion of Intravenous Nefopam on Postoperative Opioid Consumption After Video-assisted Thoracic Surgery: A Double-blind Randomized Controlled Trial

BACKGROUND

Although nefopam has been reported to have opioid-sparing and analgesic effects in postsurgical patients, its effectiveness in video-assisted thoracoscopic surgery (VATS) is unknown.

OBJECTIVES

This study aimed to investigate the opioid-sparing and analgesic effects of perioperative nefopam infusion for lung resection.

STUDY DESIGN

Double-blinded randomized controlled trial.

SETTING

Operating room, postoperative recovery room, and ward at a single tertiary university hospital.

METHODS

Ninety patients scheduled for elective VATS for lung resection were randomized to either the nefopam (group N) or control group (group C). Group N received 20 mg nefopam over 30 minutes immediately after the induction of anesthesia. Nefopam was administered continuously for 24 hours postoperative, using a dual-channel elastomeric infusion pump combined with fentanyl-based intravenous patient-controlled analgesia. Group C received the same volume of normal saline as nefopam solution administered in the same manner. The primary outcome measure was fentanyl consumption for the first postoperative 24 hours. The secondary outcome measures were the cumulative fentanyl consumption during the first postoperative 48 hours, pain intensity at rest and during coughing evaluated using an 11-point numeric rating scale, quality of recovery at postoperative time points 24 hours and 48 hours, and the occurrence of analgesic-related side effects during the first postoperative 24 hours and postoperative 24 to 48 hour period. Variables related to chronic postsurgical pain (CPSP) were also investigated by telephone interviews with patients at 3 months postoperative. This prospective randomized trial was approved by the appropriate institutional review board and was registered in the ClinicalTrials.gov registry.

RESULTS

A total of 83 patients were enrolled. Group N showed significantly lower fentanyl consumption during the first postoperative 24 hours and 48 hours (24 hours: median difference: -270 µg [95%CI, -400 to -150 µg], P < 0.001); 48 hours: median difference: -365 µg [95% CI: -610 to -140 µg], P < 0.001). Group N also showed a significantly lower pain score during coughing at 24 hours postoperative (median difference, -1 [corrected 95% CI: -2.5 to 0], adjusted P = 0.040). However, there were no significant between-group differences in the postoperative quality of recovery, occurrence of analgesic-related side effects, length of hospital stay, and occurrence of CPSP.

LIMITATIONS

Despite the significant opioid-sparing effect of perioperative nefopam infusion, it would have been difficult to observe significant improvements in other postoperative outcomes owing to the modest sample size.

CONCLUSION

Perioperative nefopam infusion using a dual-channel elastomeric infusion pump has a significant opioid-sparing effect in patients undergoing VATS for lung resection. Therefore, it could be a feasible option for multimodal analgesia in these patients.

Abstract 5131: Deep learning-based tumor microenvironment cell types mapping from H&E images of lung adenocarcinoma using spatial transcriptomic data

Purpose Spatial characterization of cell types of the tumor microenvironment (TME) is a key to finding new targets as well as developing biomarkers for immuno-oncology treatment. Here, we develop and validate a deep learning model trained by integrating H&E images of lung adenocarcinoma and spatial transcriptomic data to decipher spatial mapping of multiple cell types in TME only using H&E images.

Methods A total of 21 H&E images combined with spatial transcriptomic data of lung adenocarcinoma were used to develop a model. As each spot of spatial transcriptomic data consisted of a few cells, the cell types were inferred by CellDART, a domain adaptation-based method to estimating five cell types defined by single cell RNA-seq (scRNA-seq) data - B, T/NK, myeloid cells, fibroblasts, and epithelial cells. A convolutional neural network using H&E image patches as inputs was developed to predict the cell type scores for each corresponding spot. For the external validation, the model estimated the cell type scores from H&E-stained tissue image patches of lung adenocarcinoma of the Cancer Genome Atlas (TCGA-LUAD). Furthermore, the model inferred cell types from H&E images of lung adenocarcinoma tissues acquired by different patients and the results were compared with immunohistochemistry.

Results The cell types inferred by the model using H&E image patches were significantly correlated with those derived by spatial transcriptomic data as an internal validation. The mean value of the deep learning-based cell types scores estimated by the TCGA-LUAD tissue images was significantly correlated with the cell type scores estimated by bulk RNA-seq data of corresponding TCGA data. When cell type inference maps of independent lung adenocarcinoma H&E images were spatially co-registered with immunohistochemistry slides, including CD3, CD20, and CD68, pixel-wise correlation analysis revealed positive significant correlations.

Conclusions A deep learning model to infer spatial cell types of tumor microenvironment using H&E images was developed. The results of cell type scores were positively correlated with bulk RNA-seq-based immune cell enrichment scores and pixelwise analyses on immunohistochemistry images using typical cell type markers. This approach can provide objective and flexible deep learning-based models for characterizing tumor microenvironment.

Citation Format: Hongyoon Choi, Kwon Joong Na, Jaemoon Koh, Young Tae Kim. Deep learning-based tumor microenvironment cell types mapping from H&E images of lung adenocarcinoma using spatial transcriptomic data [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 5131.

Robotic subxiphoid thymectomy versus lateral thymectomy: A propensity-score-matched comparison

OBJECTIVES

This study aims to compare the surgical outcomes between conventional robotic lateral thymectomy and recently introduced robotic subxiphoid thymectomy for the surgical treatment of anterior mediastinal tumors.

METHODS

Between May 2008 and July 2020, the patients who underwent robotic thymectomy were included in the study. Because robotic subxiphoid thymectomy were more frequently performed in the tumors with advanced stages and located in the upper mediastinum abutting the brachiocephalic vein, we conducted propensity score matching to minimize selection bias.

RESULTS

A total of 389 patients (subxiphoid and lateral thymectomy in 188 and 200 patients, respectively) underwent robotic thymectomy, and 141 matched pairs in each group were included in the analysis. After the matching process, both methods showed comparable demographic features, pathological diagnoses, and pathologic stages. Robotic subxiphoid thymectomy was performed more frequently for mediastinal masses abutting the brachiocephalic vein (p < 0.01). The proportion of simultaneous resection of adjacent structures, including the lung, pericardium, and phrenic nerve, was similar between the two groups; however, the proportion of brachiocephalic vein resection was significantly higher in the robotic subxiphoid thymectomy (p < 0.01). Although both groups showed comparable complication rates (p = 0.80), robotic subxiphoid thymectomy was associated with shorter hospital stays (2.4 (2.4) vs 3.1 (2.4) days; p = 0.03) and a lower pain score in the immediate and early postoperative periods.

CONCLUSIONS

Robotic subxiphoid thymectomy could be performed safely in complex upper mediastinal tumors abutting the brachiocephalic vein and showed better early outcomes with shorter hospital stays and lesser postoperative pain than robotic lateral thymectomy.

CellDART: cell type inference by domain adaptation of single-cell and spatial transcriptomic data

Deciphering the cellular composition in genome-wide spatially resolved transcriptomic data is a critical task to clarify the spatial context of cells in a tissue. In this study, we developed a method, CellDART, which estimates the spatial distribution of cells defined by single-cell level data using domain adaptation of neural networks and applied it to the spatial mapping of human lung tissue. The neural network that predicts the cell proportion in a pseudospot, a virtual mixture of cells from single-cell data, is translated to decompose the cell types in each spatial barcoded region. First, CellDART was applied to a mouse brain and a human dorsolateral prefrontal cortex tissue to identify cell types with a layer-specific spatial distribution. Overall, the proposed approach showed more stable and higher accuracy with short execution time compared to other computational methods to predict the spatial location of excitatory neurons. CellDART was capable of decomposing cellular proportion in mouse hippocampus Slide-seq data. Furthermore, CellDART elucidated the cell type predominance defined by the human lung cell atlas across the lung tissue compartments and it corresponded to the known prevalent cell types. CellDART is expected to help to elucidate the spatial heterogeneity of cells and their close interactions in various tissues.

Early Outcomes of Robotic Versus Video-Assisted Thoracoscopic Anatomical Resection for Lung Cancer

Background

We compared the safety and effectiveness of robotic anatomical resection and video-assisted thoracoscopic surgery (VATS).

Methods

A retrospective analysis was conducted of the records of 4,283 patients, in whom an attempt was made to perform minimally invasive anatomical resection for lung cancer at Seoul National University Hospital from January 2011 to July 2020. Of these patients, 138 underwent robotic surgery and 4,145 underwent VATS. Perioperative outcomes were compared after propensity score matching including age, sex, height, weight, pulmonary function, smoking status, performance status, comorbidities, type of resection, combined bronchoplasty/angioplasty, tumor size, clinical T/N category, histology, and neoadjuvant treatment.

Results

In total, 137 well-balanced pairs were obtained. There were no cases of 30-day mortality in the entire cohort. Conversion to thoracotomy was required more frequently in the VATS group (VATS 6.6% vs. robotic 0.7%, p=0.008). The complete resection rate (VATS 97.8% vs. robotic 98.5%, p=1.000) and postoperative complication rate (VATS 17.5% vs. robotic 19.0%, p=0.874) were not significantly different between the 2 groups. The robotic group showed a slightly shorter hospital stay (VATS 5.8±3.9 days vs. robotic 5.0±3.6 days, p=0.052). N2 nodal upstaging (cN0/pN2) was more common in the robotic group than the VATS group, but without statistical significance (VATS 4% vs. robotic 12%, p=0.077).

Conclusion

Robotic anatomical resection in lung cancer showed comparable early outcomes when compared to VATS. In particular, robotic resection presented a lower conversion-to-thoracotomy rate. Furthermore, a robotic approach might improve lymph node harvesting in the N2 station.

Different Glucose Metabolic Features According to Cancer and Immune Cells in the Tumor Microenvironment

Background

A close metabolic interaction between cancer and immune cells in the tumor microenvironment (TME) plays a pivotal role in cancer immunity. Herein, we have comprehensively investigated the glucose metabolic features of the TME at the single-cell level to discover feasible metabolic targets for the tumor immune status.

Methods

We examined expression levels of glucose transporters (GLUTs) in various cancer types using The Cancer Genome Atlas (TCGA) data and single-cell RNA-seq (scRNA-seq) datasets of human cancer tissues including melanoma, head and neck, and breast cancer. In addition, scRNA-seq data of immune cells in the TME acquired from human melanoma after immune checkpoint inhibitors were analyzed to investigate the dynamics of glucose metabolic profiles of specific immune cells.

Results

Pan-cancer bulk RNA-seq showed that the GLUT3-to-GLUT1 ratio was positively associated with immune cell enrichment score. The scRNA-seq datasets of various human cancer tissues showed that GLUT1 was highly expressed in cancer cells, while GLUT3 was highly expressed in immune cells in TME. The scRNA-seq data obtained from human melanoma tissues pre- and post-immunotherapy showed that glucose metabolism features of myeloid cells, particularly including GLUTs expression, markedly differed according to treatment response.

Conclusions

Differently expressed GLUTs in TME suggest that GLUT could be a good candidate a surrogate of tumor immune metabolic profiles and a target for adjunctive treatments for immunotherapy.

Association of Adipopenia at Preoperative PET/CT with Mortality in Stage I Non-Small Cell Lung Cancer

Background Body mass index (BMI) and sarcopenia status are well-established prognostic factors in patients with lung cancer. However, the relationship between the amount of adipose tissue and survival remains unclear. Purpose To investigate the association between baseline adipopenia and outcomes in patients with early-stage non-small cell lung cancer (NSCLC). Materials and Methods Consecutive patients who underwent surgical resection for stage I NSCLC between 2011 and 2015 at a single tertiary care center were retrospectively identified. The primary outcome was the 5-year overall survival (OS) rate, and secondary outcomes were the 5-year disease-free survival (DFS) rate and the major postoperative complication rate. The abdominal total fat volume at the waist and the skeletal muscle area at the L3 level were obtained from preoperative PET/CT data and were normalized by the height squared to calculate the fat volume index (FVI) and skeletal muscle index. Adipopenia was defined as the sex-specific lowest quartile of the FVI for the study sample, and sarcopenia was determined using the skeletal muscle index reference value (men, <55 cm²/m²; women, <39 cm²/m²). The association between body composition and outcomes was evaluated using Cox regression analysis. Results A total of 440 patients (median age, 65 years [interquartile range, 58-72 years]; 243 men) were evaluated. Most underweight patients (<20 kg/m²) had adipopenia (97%, 36 of 37 patients), but overweight patients (25-30 kg/m², n = 138) and obese patients (>30 kg/m², n = 14) did not have adipopenia (3%, four of 152 patients). In the group with a normal BMI (20-25 kg/m²), 28% (70 of 251 patients) had adipopenia and 67% (168 of 251 patients) had sarcopenia. After adjusting for age, sex, smoking history, surgical procedure, stage, histologic type, BMI, and sarcopenia, adipopenia was associated with reduced 5-year OS (hazard ratio [HR] = 2.2; 95% CI: 1.1, 3.8; P = .02) and 5-year non-cancer-specific OS rates (HR = 3.2; 95% CI: 1.2, 8.7; P = .02). There was no association between adipopenia and postoperative complications (P = .45) or between adipopenia and the 5-year DFS rate (P = .18). Conclusion Baseline adipopenia was associated with a reduced 5-year overall survival rate in patients with early-stage non-small cell lung cancer and may indicate risk for non-cancer-related death. © RSNA, 2021 Online supplemental material is available for this article.

Long-Term Outcomes in Stage I Lung Cancer After Segmentectomy with a Close Resection Margin

Background

In general, a 2-cm surgical margin is recommended for limited resection to obtain equivalent oncologic outcomes to lobectomy for lung cancer. This study aimed to examine the patterns of recurrence and prognostic factors for recurrence in patients with a close parenchymal resection margin.

Methods

From January 2009 to April 2017, 156 patients with stage I lung cancer who underwent segmentectomy with a close resection margin (<2 cm) were enrolled. Recurrence-free survival and overall survival were assessed. In addition, predisposing factors for recurrence were evaluated.

Results

The mean tumor size was 1.7±0.8 cm and the parenchymal resection margin was 1.1±0.6 cm. Recurrence developed in 17 (10.7%) of the 156 patients, and the 5-year recurrence-free survival rate was 88.9%. Distant metastasis (7.7%) was the predominant recurrence pattern. The isolated local recurrence rate was 1.9%. Multivariate Cox regression analysis revealed that age, tumor size, mediastinal lymph node dissection, postoperative complications, and histologic type were significant predisposing factors for recurrence. However, parenchymal margin distance did not significantly affect the long-term prognosis.

Conclusion

Segmentectomy with a close resection margin for early-stage lung cancer in selected patients resulted in acceptable recurrence and survival. However, patients with tumors larger than 2 cm, squamous cell carcinoma histology, and insufficient mediastinal evaluation should be carefully followed up for recurrence.

Radiological and clinical features of screening-detected pulmonary invasive mucinous adenocarcinoma

 

OBJECTIVES

The current understanding of pulmonary invasive mucinous adenocarcinoma is largely based on studies of advanced stage patients and data about early-stage invasive mucinous adenocarcinoma are sparse. We evaluated the radiological and clinical features of screening-detected early-stage invasive mucinous adenocarcinoma (SD-IMA).

METHODS

Data from 91 patients who underwent surgical treatment for SD-IMA (≤3 cm) from 2013 to 2019 were reviewed retrospectively. Data on radiological characteristics, clinicopathological findings, recurrence and survival were obtained. Disease-free survival rate was analysed.

RESULTS

Radiologically, SD-IMAs presented as a pure ground-glass nodule (6.6%), part-solid nodule (38.5%) or solid (54.9%). Dominant locations were both lower lobes (74.7%) and peripheral area (93.4%). The sensitivity of percutaneous needle biopsy was 78.1% (25/32). Lobectomy was performed in 70 (76.9%) patients, and sublobar resection in 21 (23.1%) patients. Seventy-three (80.2%), 15 (16.5%) and 3 (3.3%) patients had pathological stage IA, IB and IIB or above, respectively. Seven patients developed recurrence, and 3 died due to disease progression. Pleural seeding developed exclusively in 2 patients who underwent needle biopsy. The 5-year disease-free survival rate was 89.4%. The disease-free survival rates at 5 years were 86.3% in the lobectomy group and 100% in the sublobar resection group.

CONCLUSIONS

SD-IMAs were mostly radiologically invasive nodules. SD-IMAs showed favourable prognosis after surgical treatment.

Robotic esophagectomy versus open esophagectomy in esophageal squamous cell carcinoma: a propensity-score matched analysis

We aimed to compare the short- and long-term outcomes between robotic esophagectomy (RE) and open esophagectomy (OE) in patients with esophageal squamous cell carcinoma (ESCC). Among the patients who underwent esophagectomy for ESCC from 2008 to 2017, 402 patients (n = 178 in RE and n = 224 in OE) were enrolled and, after propensity-score matching, 136 patients in each group were selected. The total rate of complications was comparable, whereas the rate of major complications was higher in OE (p < 0.01). Hospital stay was longer in OE (15 days in OE vs. 13 days in RE; p = 0.03) with a comparable early mortality rate. Complete resection was equally achieved in both groups (96.3% in RE vs. 97.0% in OE; p = 0.74). The numbers of retrieved lymph nodes (LN) were significantly higher in RE (42.8 in RE vs 35.3 in OE; p < 0.01), especially for LNs in the left lower cervical paratracheal, both recurrent laryngeal nerves, and paraesophageal area. The 5-year overall survival rate was higher in RE (75.1% in RE vs. 57.9% in OE; p = 0.02), whereas, the freedom from recurrence was comparable between the two groups (68.8% in RE vs. 54.7% in OE; p = 0.15). Notably, RE achieved a significantly higher rate of 5-year freedom from regional nodal recurrence than OE (81.4% in RE vs. 62.7% in OE, p = 0.03). RE contributed to a lower rate of major complications and shorter hospital stays. Furthermore, RE showed increased long-term overall survival and freedom from regional LN recurrence rates, with a higher yield of LN dissection compared to OE.

Electromagnetic Navigation Bronchoscopy-Guided Dye Marking for Localization of Pulmonary Nodules

BACKGROUND

Electromagnetic navigation bronchoscopy (ENB)-guided dye marking is a useful localization modality for small pulmonary nodules. The purpose of this study was to evaluate the efficacy and safety of intraoperative full virtual ENB-guided dye marking.

METHODS

Patients who underwent full virtual ENB-guided dye marking without adjunct intraoperative imaging (fluoroscopy or cone beam computed tomography) for small pulmonary nodules were investigated retrospectively. Efficacy was evaluated on the basis of the success rates of dye marking (visible dye mark) and nodule localization, and safety was evaluated on the basis of the rate of ENB-related complications.

RESULTS

ENB-guided dye marking was performed on 164 nodules in 134 patients. Twenty-seven (20.1%) patients had multiple nodules. The total number of dye-marking attempts was 241, and the mean number of markings per nodule was 1.5±0.7. The mean ENB procedure duration was 30±15.1 min. No ENB-related complications were observed. The success rate of dye marking was 86.7% (209/241), and that of localization was 94.5% (155/164). Among 63 nodules with multiple dye-marking attempts, 62 (98.4%) were successfully localized. In 101 nodules with a single dye-marking attempt, 88 (87.1%) were localized with the visceral pleural dye mark. Additionally, 6 (5.9%) nodules could be localized with the needle hole on the visceral pleura. The number of dye-marking attempts was a significant factor in the success of localization (1.5±0.7 versus 1.1±0.3, p=0.01).

CONCLUSIONS

Full virtual ENB-guided dye marking was effective and safe for the localization of small pulmonary nodules. A multiple dye-marking strategy is recommended to achieve a high success rate.

The robotic thymectomy via the subxiphoid approach: technique and early outcomes

OBJECTIVES

Robotic thymectomy via the subxiphoid approach (RTX) is a recently introduced surgical approach. This study aimed to report on the surgical technique and early outcomes of RTX in our institute.

METHODS

RTX was performed using the 3-arm technique in the da Vinci robotic surgical system. The camera was inserted into a subxiphoid port, and 2 robotic arms were inserted in bilateral intercostal ports. A complete dissection of both cervical poles up to the thyroid gland was conducted, and bilateral phrenic nerves were identified in all cases. Radical combined resection of adjacent organs, including the lung, pericardium, phrenic nerve and the innominate vein, was performed if necessary. The resected specimen could be retrieved through the subxiphoid port site.

RESULTS

A total of 110 patients underwent RTX in our institute from October 2016 to August 2019. Thymoma was the most common diagnosis (60.9%), and the mean size of the tumours was 4.9 ± 2.4 cm. Combined resection was performed in the lung (n = 9, 8.1%), pericardium (n = 6, 5.5%) and innominate vein (n = 5, 4.5%). There were 2 minor postoperative complications (1.8%), and the mean length of hospital stay was 2.2 ± 1.4 days. For the cumulative sum curve analysis of the learning curve using operative time, 50 cases were necessary to gain proficiency.

CONCLUSIONS

RTX was a safe and feasible surgical approach, even in advanced thymic epithelial tumours. It should be considered one of the valuable surgical options in minimally invasive thymectomy.

Differences in Tumor Immune Microenvironment in Metastatic Sites of Breast Cancer

Introduction: Tumor immune microenvironment (TIME) promotes immune escape, allowing for tumor progression and metastasis. In spite of the current evidence of the complicated role of immune cells in promoting or suppressing cancer progression, the heterogeneity of TIME according to the tumor site has been scarcely investigated. Here, we analyzed transcriptomic profiles of metastatic breast cancer to understand how TIME varies according to tumor sites.

Methods: Two gene expression datasets from metastatic breast cancer of various sites and a single-cell RNA sequencing dataset of primary breast cancer and metastatic lymph nodes were analyzed. The immune cell-type enrichment of each tumor was estimated. Immune cell types were identified by clustering analysis, and the proportions of cell types in TIME were assessed according to the tumor site.

Results: Metastatic bone lesions showed more neutrophils than breast lesions. Tumors clustered according to immune cell type were significantly associated with tumor site. In single-cell analyses, the TIMEs of metastatic lymph nodes showed fewer macrophages than those of primary tumors. Differentially expressed gene signatures in the primary tumor and metastatic lymph nodes were associated with macrophage activation.

Conclusion: We conclude that metastatic sites show variable enrichment patterns of immune cells, and that the TIME of metastatic lesions should be considered in precise immuno-oncology treatments.

Trends in Extracorporeal Membrane Oxygenation Application and Outcomes in Korea

The use of extracorporeal membrane oxygenation (ECMO) is increasing despite the limited evidence in survival benefit. This study aimed to analyze the changes of in-hospital mortality, medical costs, and other outcomes in ECMO therapy. We used 2004-2017 data from a nationwide healthcare administrative claims database in Korea. Overall, 14,775 ECMO procedures were performed in 14,689 patients at 112 hospitals. We found a 170-fold and a 334-fold increase in the number of ECMO procedures and related costs, respectively. For indications, the performance of ECMO for heart or lung transplantation and respiratory failure increased, whereas that for cardiovascular surgery decreased. The duration of ECMO increased from a median of 3 days (IQR, 2-5 days) in 2004 to 4 days (IQR, 2-9 days) in 2017. The overall in-hospital mortality rate was 68.6%, and this improved over time, especially for lung transplantation and respiratory failure patients. Bleeding-related complications and the transfusion amount also decreased. Hospitals with higher case volume showed better survival outcomes. The median cost per procedure and per day was 26,538 USD (IQR, 14,646-47,862 USD) and 1,560 USD (IQR, 903-2,929 USD), respectively, and increased with time. A trend toward greater resource use and better outcomes requires additional cost-effective analysis based on indications.

Three-Dimensional Human Alveolar Stem Cell Culture Models Reveal Infection Response to SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is the cause of a present pandemic, infects human lung alveolar type 2 (hAT2) cells. Characterizing pathogenesis is crucial for developing vaccines and therapeutics. However, the lack of models mirroring the cellular physiology and pathology of hAT2 cells limits the study. Here, we develop a feeder-free, long-term, three-dimensional (3D) culture technique for hAT2 cells derived from primary human lung tissue and investigate infection response to SARS-CoV-2. By imaging-based analysis and single-cell transcriptome profiling, we reveal rapid viral replication and the increased expression of interferon-associated genes and proinflammatory genes in infected hAT2 cells, indicating a robust endogenous innate immune response. Further tracing of viral mutations acquired during transmission identifies full infection of individual cells effectively from a single viral entry. Our study provides deep insights into the pathogenesis of SARS-CoV-2 and the application of defined 3D hAT2 cultures as models for respiratory diseases.

Comparison between lung perfusion scan and single-photon emission computed tomography/computed tomography for predicting postoperative lung function after pulmonary resection in patients with borderline lung function

OBJECTIVES

We compared the usefulness of single-photon emission computed tomography/computed tomography (SPECT/CT) and lung perfusion scintigraphy (LPS) for predicting postoperative lung function by comparing patients with borderline lung function.

METHODS

A total of 274 patients who underwent simultaneous LPS and SPECT/CT and had a forced expiratory volume in 1 s (FEV1) or diffusing capacity for carbon monoxide (DLCO) under 80% were included. The % uptake by LPS was calculated by the posterior-oblique method. The concordance and difference of the % uptake, predicted postoperative (ppo) FEV1 and ppoDLCO as determined by 2 methods were evaluated. The association between ppo values and actual postoperative FEV1 and DLCO was examined. Subgroup analysis was conducted in redo-operation cases.

RESULTS

The % uptake of each lobe, except the right middle lobe, showed fair concordance (concordance correlation coefficients for right upper, middle, lower, left upper and lower lobe = 0.61, 0.37, 0.71, 0.66 and 0.69, respectively). ppoFEV1 and ppoDLCO also revealed high concordance between both methods (concordance correlation coefficient = 0.93 for ppoFEV1 and concordance correlation coefficient = 0.92 for ppoDLCO) without a significant difference (P = 0.42 for ppoFEV1; P = 0.31 for ppoDLCO). Both ppoFEV1 and ppoDLCO showed a significantly high correlation with the actual FEV1 (r = 0.77, P < 0.01 for LPS, r = 0.77, P < 0.01 for SPECT/CT) and DLCO (r = 0.62, P < 0.01 for LPS, r = 0.62, P < 0.01 for SPECT/CT). High concordance of % uptake, ppoFEV1 and ppoDLCO was present in redo-operation patients.

CONCLUSIONS

Both LPS and SPECT/CT showed high predictability for actual postoperative lung function, and LPS showed good performance to estimate ppoFEV1 and ppoDLCO with reference to SPECT/CT, even in redo-operation cases.

Long-Term Outcomes of Robotic Thymectomy in Patients With Thymic Epithelial Tumors

BACKGROUND

The long-term outcomes of robotic thymectomy for thymic epithelial tumors (TETs) are not well known, even though the early postoperative outcomes have improved. This study aimed to report the long-term survival and recurrence in patients with TETs who underwent robotic thymectomies.

METHODS

A total of 158 patients who underwent robotic thymectomy for TET and who were followed-up for more than 1 year were included in the study. The median follow-up time was 43 (interquartile range, 40) months, and 156 (98%) patients were followed completely until the end of the study period.

RESULTS

The mean age of the patients was 55.7 ± 12.7 years, and the mean size of the tumor was 4.6 ± 2.1 cm. There was no postoperative mortality and postoperative complications occurred in 7 (4.4%) patients. The median length of the postoperative hospital stay was 2 (interquartile range, 1-20) days. Thymoma was the most common cell type (n = 132, 84%), and thymic carcinoma (n = 24, 15%) and neuroendocrine tumors (n = 2, 1%) were the next most common types. Advanced stages more than stage III were identified in 15 patients (stage IIIA: n = 7, 4%; stage IVA: n = 5, 3%; and stage IVB: n = 3, 2%). The 5-year disease-specific survival was 100% in thymoma and 95% in thymic carcinoma. The 5-year recurrence-free survival was 94% in thymoma and 79% in thymic carcinoma.

CONCLUSIONS

Robotic thymectomy could achieve favorable long-term survival and recurrence rates, comparable to open or thoracoscopic thymectomy.

Tumor immune profiles noninvasively estimated by FDG PET with deep learning correlate with immunotherapy response in lung adenocarcinoma

Rationale: The clinical application of biomarkers reflecting tumor immune microenvironment is hurdled by the invasiveness of obtaining tissues despite its importance in immunotherapy. We developed a deep learning-based biomarker which noninvasively estimates a tumor immune profile with fluorodeoxyglucose positron emission tomography (FDG-PET) in lung adenocarcinoma (LUAD).

Methods: A deep learning model to predict cytolytic activity score (CytAct) using semi-automatically segmented tumors on FDG-PET trained by a publicly available dataset paired with tissue RNA sequencing (n = 93). This model was validated in two independent cohorts of LUAD: SNUH (n = 43) and The Cancer Genome Atlas (TCGA) cohort (n = 16). The model was applied to the immune checkpoint blockade (ICB) cohort, which consists of patients with metastatic LUAD who underwent ICB treatment (n = 29).

Results: The predicted CytAct showed a positive correlation with CytAct of RNA sequencing in validation cohorts (Spearman rho = 0.32, p = 0.04 in SNUH cohort; spearman rho = 0.47, p = 0.07 in TCGA cohort). In ICB cohort, the higher predicted CytAct of individual lesion was associated with more decrement in tumor size after ICB treatment (Spearman rho = -0.54, p < 0.001). Higher minimum predicted CytAct in each patient associated with significantly prolonged progression free survival and overall survival (Hazard ratio 0.25, p = 0.001 and 0.18, p = 0.004, respectively). In patients with multiple lesions, ICB responders had significantly lower variance of predicted CytActs (p = 0.005).

Conclusion: The deep learning model that predicts CytAct using FDG-PET of LUAD was validated in independent cohorts. Our approach may be used to noninvasively assess an immune profile and predict outcomes of LUAD patients treated with ICB.

Current Issues in Minimally Invasive Esophagectomy

Minimally invasive esophagectomy (MIE) was first introduced in the 1990s. Currently, it is a widely accepted surgical approach for the treatment of esophageal cancer, as it is an oncologically sound procedure; its advantages when compared to open procedures, including reduction in postoperative complications, reduction in the length of hospital stay, and improvement in quality of life, are well documented. However, debates are still ongoing about the safety and efficacy of MIE. The present review focuses on some of the current issues related to conventional MIE and robot-assisted MIE based on evidence from the current literature.

Reciprocal change in Glucose metabolism of Cancer and Immune Cells mediated by different Glucose Transporters predicts Immunotherapy response

The metabolic properties of tumor microenvironment (TME) are dynamically dysregulated to achieve immune escape and promote cancer cell survival. However, in vivo properties of glucose metabolism in cancer and immune cells are poorly understood and their clinical application to development of a biomarker reflecting immune functionality is still lacking.

Methods: We analyzed RNA-seq and fluorodeoxyglucose (FDG) positron emission tomography profiles of 63 lung squamous cell carcinoma (LUSC) specimens to correlate FDG uptake, expression of glucose transporters (GLUT) by RNA-seq and immune cell enrichment score (ImmuneScore). Single cell RNA-seq analysis in five lung cancer specimens was performed. We tested the GLUT3/GLUT1 ratio, the GLUT-ratio, as a surrogate representing immune metabolic functionality by investigating the association with immunotherapy response in two melanoma cohorts.

Results: ImmuneScore showed a negative correlation with GLUT1 (r = -0.70, p < 0.01) and a positive correlation with GLUT3 (r = 0.39, p < 0.01) in LUSC. Single-cell RNA-seq showed GLUT1 and GLUT3 were mostly expressed in cancer and immune cells, respectively. In immune-poor LUSC, FDG uptake was positively correlated with GLUT1 (r = 0.27, p = 0.04) and negatively correlated with ImmuneScore (r = -0.28, p = 0.04). In immune-rich LUSC, FDG uptake was positively correlated with both GLUT3 (r = 0.78, p = 0.01) and ImmuneScore (r = 0.58, p = 0.10). The GLUT-ratio was higher in anti-PD1 responders than nonresponders (p = 0.08 for baseline; p = 0.02 for on-treatment) and associated with a progression-free survival in melanoma patients who treated with anti-CTLA4 (p = 0.04).

Conclusions: Competitive uptake of glucose by cancer and immune cells in TME could be mediated by differential GLUT expression in these cells.

Efficacy and Cost-effectiveness of Surgical Biopsy for Histologic Diagnosis of Indeterminate Nodules Suspected for Early Stage Lung Cancer: Comparison with Percutaneous Needle Biopsy

BACKGROUND

Indeterminate pulmonary nodules (IPN) suspected for early stage lung cancer mandate accurate diagnosis. Both percutaneous needle biopsy (PCNB) and surgical biopsy (SB) are valuable options. The present study aimed to compare the efficacy and cost-effectiveness between PCNB and SB for IPN suspected for early stage lung cancer.

METHODS

During January-November 2018, patients who underwent operation for IPN suspected for early stage lung cancer (SB group, n = 245) or operation after PCNB (PCNB group, n = 113) were included. Patient-level cost data were extracted from medical bills from the institution. Propensity score matching was performed between the two groups from a retrospectively-collected database.

RESULTS

Fifteen patients (11.5%) had complications after PCNB; thirteen (11.5%) were not confirmed to have lung cancer through PCNB but underwent operation for IPN. In SB group, 172 (70.2%) and 7 (2.9%) patients underwent wedge resection and segmentectomy for SB, respectively; 66 patients (26.9%) underwent direct lobectomy without SB. After propensity score matching, 58 paired samples were produced. Most patients in PCNB group were admitted twice (n = 55, 94.8%). The average hospital stay was longer in PCNB group (12.9 ± 5.3 vs. 7.3 ± 3.0, P < 0.001). Though the cost of the operation was comparable (USD 12,509 ± 2,909 vs. 12,669 ± 3,334; P = 0.782), the total cost was higher for PCNB group (USD 14,403 ± 3,085 vs. 12,669 ± 3,334; P = 0.006). The average subcategory cost, which increases proportional to hospital stay, was higher in PCNB group, whereas the cost of operation and surgical materials were comparable between the two groups.

CONCLUSION

Lung cancer operation following SB for IPN was associated with lesser cost, shorter hospital stays, and lesser admission time than lung cancer operation after PCNB. The increased cost and longer hospital stay appear largely related to the admission for PCNB.

Robotic thymectomy for advanced thymic epithelial tumor: indications and technical aspects

Robotic thymectomy is widely accepted as a valuable treatment option for surgical resection of thymic epithelial tumor as minimally invasive surgery has shown better early clinical outcomes than open surgery. Technical advances in robotic surgery have expanded the indications for robotic thymectomy, and the technique can be used to perform complete resection of advanced thymic epithelial tumor requiring concomitant resection of adjacent structures. To ensure complete resection, a multi-disciplinary approach, with thorough preoperative evaluation, must be adopted to determine whether a patient shows surgical indications for advanced thymic epithelial tumor. The early clinical outcomes after robotic thymectomy to treat advanced thymic epithelial tumor are promising; however, the long-term oncologic outcomes should be evaluated in the further studies.

Outcomes after total robotic esophagectomy for esophageal cancer: a propensity-matched comparison with hybrid robotic esophagectomy

Background

Robot-assisted minimally invasive esophagectomy (RAMIE) reduces postoperative respiratory complications and enables meticulous mediastinal lymphadenectomy. However, whether adding a robotic abdominal procedure to a robotic thoracic procedure can result in better outcomes is unclear. We examined outcomes after total-RAMIE (T-RAMIE) and compared them with the outcomes after hybrid-RAMIE (H-RAMIE).

Methods

Total of 227 patients who underwent robotic esophagectomy for esophageal cancer were included. T-RAMIE was defined as esophagectomy performed robotically in both the thoracic and abdominal cavities. Laparotomy was used instead of the robotic procedure in H-RAMIE. T-RAMIE was performed in 144 patients (63.4%), and propensity score matching produced 49 matched pairs from each group. Early and long-term clinical outcomes between the two groups were compared.

Results

T-RAMIE was mostly performed for upper or mid-thoracic squamous cell carcinoma (n=119, 82.6%) and cervical anastomosis, and three-field lymphadenectomy was performed in 113 (78.5%) and 54 (37.5%) patients, respectively. One laparotomy conversion was necessary because of severe obesity. The propensity-matched analysis demonstrated that T-RAMIE showed a comparable 90-day mortality rate with H-RAMIE (0% vs. 6.1%, P=0.083). The incidence rates of total (63.3% vs. 63.3%; P=1.000), abdominal (8.2% vs. 14.3%; P=0.366), and respiratory complications (10.2% vs. 10.2%; P=1.000) were not different between two groups. The number of harvested abdominal lymph nodes was similar (12.4±9.0 vs. 12.3±8.9; P=0.992). Median follow-up duration for T-RAMIE and H-RAMIE was 16.3 and 23.5 months, respectively. Two-year overall survival rate (86.2% in T-RAMIE vs. 77.6% in H-RAMIE; P=0.150) and recurrence-free survival (76.6% in T-RAMIE vs. 62.2% in H-RAMIE; P=0.280) were comparable between the two groups.

Conclusions

In this matched analysis, T-RAMIE and H-RAMIE showed comparable early outcomes and long-term survival. The low tendencies of early mortality and conversion rate of T-RAMIE suggest that it might be a safe alternative to open stomach mobilization and abdominal lymphadenectomy.

Primary Extraskeletal Osteosarcoma in the Anterior Mediastinum: A Case Report and Review

Extraskeletal osteosarcoma (ESOS) is a malignant soft tissue neoplasm producing osteoid, without any continuity with the bone or periosteum. Primary ESOS presenting in the mediastinum is an extremely rare, yet aggressive malignant tumor associated with a poor prognosis. We report a case of primary ESOS arising from the thymus in a 63-year-old male patient.

Pan-cancer analysis of tumor metabolic landscape associated with genomic alterations

Although metabolic alterations are one of the hallmarks of cancer, there is a lack of understanding of how metabolic landscape is reconstituted according to cancer progression and which genetic alterations underlie its heterogeneity within cancer cells. Here, the configuration of the metabolic landscape according to genetic alteration is examined across 7648 subjects representing 29 cancers. The metabolic landscape and its reconfiguration according to the accumulated mutation maintained characteristics of their tissue of origin. However, there were some common patterns across cancers in terms of the association with cancer progression. Carbohydrate and pyrimidine metabolism showed the highest positive correlation with tumor metabolic burden and they were also common poor prognostic pathways in several cancer types. We additionally examined whether genetic alterations associated with the heterogeneity of metabolic landscape. Genetic alterations associated with each metabolic pathway differed between cancers, however, they were a part of cancer drivers in most cancer types.