Correlation of tumor-related immunity with 18F-FDG-PET in pulmonary squamous-cell carcinoma

Prognostic significance of 18F-Fluorodeoxyglucose positron-emission tomography parameters in patients with biliary tract cancers: a meta-analysis

BACKGROUND AND OBJECTIVE

Numerous previous studies have assessed the prognostic role of 18F-fluorodeoxyglucose positron-emission tomography (18F FDG PET) in patients with biliary tract cancer (BTC), but those results were inconsistent. The present study aims to determine the predictive value of 18F FDG PET in BTC patients via a meta-analysis.

METHODS

The underlying studies related to 18F FDG PET and BTC patients` outcomes were searched and identified in the online databases. The interested parameters include total lesion glycolysis (TLG), metabolic tumor volume (MTV), primary tumor and metastatic lymph node (LN) maximum standardized uptake value (SUVmax), as well as change of SUVmax (ΔSUVmax) during treatment. Overall survival (OS), disease-free survival (DFS), and progression-free survival (PFS) were considered as the primary endpoints. Hazard ratio (HR) and corresponding 95% confidence intervals (CIs) were defined as the effective measure and calculated by a pooled analysis. Publication bias was assessed by funnel plot, Bagg's and Egger's tests.

RESULTS

Totally, 23 studies involving 1478 patients were included in the present meta-analysis. After a pooled analysis, it revealed that a high SUVmax was significantly associated with a poor OS (HR:2.07, 95%CI: 1.74-2.46, P = 0.000) and DFS (HR: 2.28, 95%CI: 1.53-3.41, P = 0.000). In addition, an increased TLG level contributed to a shorter OS (HR:1.91, 95%CI: 1.26-2.90, P = 0.002) and DFS (HR: 4.34, 95%CI: 1.42-13.27, P = 0.01). Moreover, we confirmed that an elevated MTV was significantly associated with increased mortality (HR:2.04, 95%CI:1.26-3.31, P = 0.004) and disease relapse (HR: 3.88, 95%CI:1.25-12.09, P = 0.019) risks. Besides, the present study uncovered that increased ΔSUVmax could predict poor OS (HR:1.26, 95%CI:1.06-1.50, P = 0.008) instead of PFS (HR: 1.96, 95%CI: 0.82-4.72, P = 0.280). Lastly, we found that LN SUVmax did not link to OS (HR: 1.49, 95%CI: 0.83-2.68, P = 0.178). No obvious publication bias was detected in the present study.

CONCLUSION

18F FDG PET parameters, including SUVmax, TLG, MTV, and ΔSUVmax, could be applied as convenient and reliable factors for predicting BTC patients` outcomes.

Predictive value of 18 F-FDG PET/CT and serum tumor markers for tumor mutational burden in patients with non-small cell lung cancer

PURPOSE

To investigate the correlations between metabolic parameters (MPs) of 18 F-fluorodeoxyglucose (FDG) uptake on positron emission tomography/computed tomography (PET/CT), serum tumor markers (STMs), and tumor mutational burden (TMB) in patients with non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

In this retrospective study, we enrolled 129 patients with NSCLC (males, 78; females, 51) who underwent baseline TMB and STM tests and 18 F-FDG PET/CT scans before treatment between March 2018 and September 2022. Patients were categorized into TMB-high (TMB ≥10 mutations/Mb; n = 27 [20.9%]) and non-TMB-high (TMB <10 mutations/Mb; n = 102 [79.1%]) groups. Binary logistic regression analyses were performed to determine independent predictors of TMB-high. Univariate and multivariate linear regression analyses were performed to determine independent predictors of TMB level on a log scale. Subgroup analyses for adenocarcinoma (ADC), ADC with EGFR+, ADC with EGFR-, and squamous cell carcinoma (SCC) were performed.

RESULTS

For ADC, all MPs (SULpeak , SULmax , SULmean , MTV, and TLG) were significantly higher in the TMB-high group than the non-TMB-high group; smoker (odds ratio [OR] = 27.08, p = 0.018), EGFR+ (OR = 0.03, p = 0.033), KRAS+ (OR = 7.98, p = 0.083), high CEA (OR = 33.56, p = 0.029), and high CA125 (OR = 13.68, p = 0.030) were independent predictors of TMB-high; and all MPs showed significant positive linear correlations with TMB on a log scale, with SULpeak as an independent predictor. However, no significant correlation was observed for SCC.

CONCLUSION

MPs and STMs can predict the TMB level for patients with ADC, and may serve as potential substitutes for TMB with increased value and easy implementation in guiding immunotherapy through noninvasive methods.

Tumor infiltrating lymphocytes and radiological picture of the tumor

Tumor microenvironment (TME) is a complex entity that includes besides the tumor cells also a whole range of immune cells. Among various populations of immune cells infiltrating the tumor, tumor infiltrating lymphocytes (TILs) are a population of lymphocytes characterized by high reactivity against the tumor component. As, TILs play a key role in mediating responses to several types of therapy and significantly improve patient outcomes in some cancer types including for instance breast cancer and lung cancer, their assessment has become a good predictive tool in the evaluation of potential treatment efficacy. Currently, the evaluation of the density of TILs infiltration is performed by histopathological. However, recent studies have shed light on potential utility of several imaging methods, including ultrasonography, magnetic resonance imaging (MRI), positron emission tomography-computed tomography (PET-CT), and radiomics, in the assessment of TILs levels. The greatest attention concerning the utility of radiology methods is directed to breast and lung cancers, nevertheless imaging methods of TILs are constantly being developed also for other malignancies. Here, we focus on reviewing the radiological methods used to assess the level of TILs in different cancer types and on the extraction of the most favorable radiological features assessed by each method.

Correlation of 18F-FDG PET/CT metabolic parameters with the expression of immune biomarkers in the tumour microenvironment in lung adenocarcinoma

AIM

To explore the association between metabolic parameters evaluated by integrated 2-[¹⁸F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET)/computed tomography (CT) and the expression of immune biomarkers in the tumour microenvironment in lung adenocarcinoma.

MATERIALS AND METHODS

This study included 134 patients. Metabolic parameters were obtained by PET/CT. Immunohistochemistry analysis was used for FOXP3-TILs (transcription factor forkhead box protein 3 tumour-infiltrating lymphocytes), CD8-TILs, CD4-TILs, CD68-TAMs (tumour-associated macrophages) and galectin-1 (Gal-1) tumour expression.

RESULTS

There were significant positive associations between FDG PET metabolic parameters and the median percentage of immune reactive areas (IRA%) covered by FOXP3-TILs and CD68-TAMs. Negative associations with the median IRA% covered by CD4-TILs and CD8-TILs were observed: maximal standardised uptake value (SUV_max), metabolic tumour volume (MTV), total lesion glycolysis (TLG), and IRA% for FOXP3-TILs (rho = 0.437, 0.400, 0.414; p<0.0001 for all parameters); SUV_max, MTV, TLG, and IRA% for CD68-TAMs (rho = 0.356, 0.355, 0.354; p<0.0001 for all parameters); SUV_max, MTV, TLG, and IRA% for CD4-TILs (rho = -0.164, -0.190, -0.191; p=0.059, 0.028, 0.027, respectively); SUV_max, MTV, TLG, and IRA% for CD8-TILs (rho = -0.305, -0.316, -0.322; p<0.0001 for all parameters). There were significant positive associations between tumour Gal-1 expression and the median IRA% covered by FOXP3-TILs and CD68-TAMs (rho = 0.379; p<0.0001; rho = 0.370; p<0.0001, respectively), and a significant negative association with the median IRA% covered by CD8-TILs (rho = -0.347; p<0.0001) was observed. Tumour stage (p=0.008), Gal-1 expression (p=0.008), and median IRA% covered by CD8-TILs (p=0.054) were independent risk factors for overall survival.

CONCLUSION

FDG PET may facilitate a comprehensive evaluation of the tumour microenvironment and predict response to immunotherapy.

Comprehensive 18F-FDG PET-based radiomics in elevating the pathological response to neoadjuvant immunochemotherapy for resectable stage III non-small-cell lung cancer: A pilot study

PURPOSE

To develop a comprehensive PET radiomics model to predict the pathological response after neoadjuvant toripalimab with chemotherapy in resectable stage III non-small-cell lung cancer (NSCLC) patients.

METHODS

Stage III NSCLC patients who received three cycles of neoadjuvant toripalimab with chemotherapy and underwent ¹⁸F-FDG PET/CT were enrolled. Baseline ¹⁸F-FDG PET/CT was performed before treatment, and preoperative ¹⁸F-FDG PET/CT was performed three weeks after the completion of neoadjuvant treatment. Surgical resection was performed 4-5 weeks after the completion of neoadjuvant treatment. Standardized uptake value (SUV) statistics features and radiomics features were derived from baseline and preoperative PET images. Delta features were derived. The radiologic response and metabolic response were assessed by iRECIST and iPERCIST, respectively. The correlations between PD-L1 expression, driver-gene status, peripheral blood biomarkers, and the pathological responses (complete pathological response [CPR]; major pathological response [MPR]) were assessed. Associations between PET features and pathological responses were evaluated by logistic regression.

RESULTS

Thirty patients underwent surgery and 29 of them performed preoperative PET/CT. Twenty patients achieved MPR and 16 of them achieved CPR. In univariate analysis, five SUV statistics features and two radiomics features were significantly associated with pathological responses. In multi-variate analysis, SUV_max, SUV_peak, SUL_peak, and End-PET-GLDM-LargeDependenceHighGrayLevelEmphasis (End-GLDM-LDHGLE) were independently associated with CPR. SUV_peak and SUL_peak performed better than SUV_max and SUL_max for MPR prediction. No significant correlation, neither between the radiologic response and the pathological response, nor among PD-L1, driver gene status, and baseline PET features was found. Inflammatory response biomarkers by peripheral blood showed no difference in different treatment responses.

CONCLUSION

The logistic regression model using comprehensive PET features contributed to predicting the pathological response after neoadjuvant toripalimab with chemotherapy in resectable stage III NSCLC patients.

Expression of Programmed Cell Death 1 Ligand 2 in Patients With Thymoma and Thymomatous Myasthenia Gravis

OBJECTIVES

This study aimed to examine the expression of programmed cell death 1 ligand 2 (PD-L2) in thymoma and thymomatous myasthenia gravis (MG).

METHODS

The records of 70 patients with thymoma receiving surgical resection between January 2017 and December 2018 were retrospectively reviewed. Thymoma PD-L2 expression was evaluated by immunohistochemistry staining. Associations between PD-L2 expression and clinicopathologic features were examined.

RESULTS

PD-L2 expression was positive in 41 patients (58.6%) and negative in 29 patients (41.4%). Of them, 33 had thymomatous MG. Patients with MG were more likely to be 50 years of age or younger (69.70% vs 35.14%); have more World Health Organization (WHO) type B thymomas (84.85% vs 64.86%); have tumors of smaller size (4.09 ± 2.33 cm vs 6.47 ± 2.42 cm); have positive PD-L2 expression (78.79% vs 40.54%); and have a higher percentage of PD-L2-positive cells, higher PD-L2 expression intensity, and score (all P < .05). Positive PD-L2 expression was associated with more type B thymomas, higher Masaoka-Koga stage, smaller tumor size, ectopic thymus, and MG (all P < .05). Factors significantly associated with MG were age under 50 years, tumor size less than 5 cm, and positive PD-L2 expression (all P < .05).

CONCLUSIONS

Thymoma PD-L2 expression is significantly associated with thymomatous MG and WHO histologic types B2 and B3.

The predictive value of total-body PET/CT in non-small cell lung cancer for the PD-L1 high expression

Purpose

Total-body positron emission tomography/computed tomography (PET/CT) provides faster scanning speed, higher image quality, and lower injected dose. To compensate for the shortcomings of the maximum standard uptake value (SUVmax), we aimed to normalize the values of PET parameters using liver and blood pool SUV (SUR-L and SUR-BP) to predict programmed cell death-ligand 1 (PD-L1) expression in non-small cell lung cancer (NSCLC) patients.

Materials and methods

A total of 138 (104 adenocarcinoma and 34 squamous cell carcinoma) primary diagnosed NSCLC patients who underwent ¹⁸F-FDG-PET/CT imaging were analyzed retrospectively. Immunohistochemistry (IHC) analysis was performed for PD-L1 expression on tumor cells and tumor-infiltrating immune cells with 22C3 antibody. Positive PD-L1 expression was defined as tumor cells no less than 50% or tumor-infiltrating immune cells no less than 10%. The relationships between PD-L1 expression and PET parameters (SUVmax, SUR-L, and SUR-BP) and clinical variables were analyzed. Statistical analysis included χ² test, receiver operating characteristic (ROC), and binary logistic regression.

Results

There were 36 patients (26%) expressing PD-L1 positively. Gender, smoking history, Ki-67, and histologic subtype were related factors. SUVmax, SUR-L, and SUR-BP were significantly higher in the positive subset than those in the negative subset. Among them, the area under the curve (AUC) of SUR-L on the ROC curve was the biggest one. In NSCLC patients, the best cutoff value of SUR-L for PD-L1-positive expression was 4.84 (AUC = 0.702, P = 0.000, sensitivity = 83.3%, specificity = 54.9%). Multivariate analysis confirmed that age and SUR-L were correlated factors in adenocarcinoma (ADC) patients.

Conclusion

SUVmax, SUR-L, and SUR-BP had utility in predicting PD-L1 high expression, and SUR-L was the most reliable parameter. PET/CT can offer reference to screen patients for first-line atezolizumab therapy.

Monitoring of Current Cancer Therapy by Positron Emission Tomography and Possible Role of Radiomics Assessment

Evaluation of cancer therapy with imaging is crucial as a surrogate marker of effectiveness and survival. The unique response patterns to therapy with immune-checkpoint inhibitors have facilitated the revision of response evaluation criteria using FDG-PET, because the immune response recalls reactive cells such as activated T-cells and macrophages, which show increased glucose metabolism and apparent progression on morphological imaging. Cellular metabolism and function are critical determinants of the viability of active cells in the tumor microenvironment, which would be novel targets of therapies, such as tumor immunity, metabolism, and genetic mutation. Considering tumor heterogeneity and variation in therapy response specific to the mechanisms of therapy, appropriate response evaluation is required. Radiomics approaches, which combine objective image features with a machine learning algorithm as well as pathologic and genetic data, have remarkably progressed over the past decade, and PET radiomics has increased quality and reliability based on the prosperous publications and standardization initiatives. PET and multimodal imaging will play a definitive role in personalized therapeutic strategies by the precise monitoring in future cancer therapy.

Prognostic Potential of Metabolic Activity on 18F-FDG Accumulation in Advanced NSCLC Receiving Combining Chemotherapy Plus PD-1 Blockade

Combined chemotherapy plus programmed death-1 (PD-1) blockade is an established treatment against patients with advanced non-small cell lung cancer (NSCLC). However, a promising predictor besides programmed death ligand-1 expression remains uncertain. We examined the prognostic significance of baseline 18F-FDG-positron emission tomography for predicting first-line combined chemotherapy plus PD-1 blockade in NSCLC patients. Forty-five patients with advanced NSCLC who received 18F-FDG-positron emission tomography immediately before combined platinum-based chemotherapy with PD-1 blockade as first-line setting were eligible for this study, and assessment of maximum of standard uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) on 18F-FDG uptake was performed. The objective response rate, median progression-free survival, and overall survival were 51.2%, 206 days, and 681 days, respectively. High SUVmax, TLG, and MTV significantly correlated with age and performance status (PS), C-reactive protein (CRP), and PS, CRP, albumin, and baseline tumor size, respectively. Univariate analysis identified albumin, TLG and MTV as significant predictors of progression-free survival, and CRP, albumin, TLG and MTV as significant factors for predicting overall survival. High TLG was confirmed as an independent factor associated with poor prognosis in multivariate analysis. In particular, TLG is identified as the most powerful predictor in patients with good PS, adenocarcinoma, programmed death ligand-1≥1%, and low baseline tumor size. The tumor metabolic volume by MTV and TLG at pretreatment was clarified as a significant predictor for combined chemotherapy with PD-1 blockade, but not maximal glycolytic level by SUVmax.

Prospective assessment using 18F-FDG PET/CT as a novel predictor for early response to PD-1 blockade in non-small-cell lung cancer

Anti-programmed death-1 (PD-1) blockade is a standard treatment for advanced non-small-cell lung cancer (NSCLC). However, no appropriate modality exists for monitoring its therapeutic response immediately after initiation. Therefore, we aimed to elucidate the clinical relevance of ¹⁸F-FDG PET/CT versus CT in predicting the response to PD-1 blockade in the early phase. This prospective study included a total of 54 NSCLC patients. ¹⁸F-FDG PET/CT was performed at 4 weeks and 9 weeks after PD-1 blockade monotherapy. Maximum standardized uptake values (SUL_max), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were evaluated. Among all patients, partial metabolic response and progressive metabolic disease after PD-1 blockade were observed in 35.2% and 11.1% on SUL_max, 22.2% and 51.8% on MTV, and 27.8% and 46.3% on TLG, respectively, whereas a partial response (PR) and progressive disease (PD), respectively, based on RECIST v1.1 were recognized in 35.2% and 35.2%, respectively. The predictive probability of PR (MTV: 57.9% vs. 21.1%, p = 0.044; TLG: 63.2% vs. 21.1%, p = 0.020) and PD (MTV: 78.9% vs. 47.3%, p = 0.002; TLG: 73.7% vs. 21.1%, p = 0.007) detected based on RECIST at 4 weeks after PD-1 blockade initiation was significantly higher using MTV or TLG on ¹⁸F-FDG uptake than on CT. Multivariate analysis revealed that metabolic response by MTV or TLG at 4 weeks was an independent factor for response to PD-1 blockade treatment. Metabolic assessment by MTV or TLG was superior to morphological changes on CT for predicting the therapeutic response and survival at 4 weeks after PD-1 blockade.

Application of molecular imaging in immune checkpoints therapy: From response assessment to prognosis prediction

Recently, immune checkpoint therapy (ICT) represented by programmed cell death1 (PD-1) and its major ligands, programmed death ligand 1 (PD-L1), has achieved significant success. Detection of PD-L1 by immunohistochemistry (IHC) is a classic method to guide the treatment of ICT patients. However, PD-L1 expression in the tumor microenvironment is highly complex. Thus, PD-L1 IHC is inadequate to fully understand the relevance of PD-L1 levels in the whole body and their dynamics to improve therapeutic outcomes. Intriguingly, numerous studies have revealed that molecular imaging technologies could potentially meet this need. Therefore, the purpose of this narrative review is to summarize the preclinical and clinical application of ICT guided by molecular imaging technology, and to explore the future opportunities and practical difficulties of these innovations.

Prognostic Significance of PD-L1 Expression and Standardized Uptake Values in the Primary Lesions of Stage IV Adenocarcinoma Lung Cancer

Background

This study evaluated the prognostic ability of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) in patients with stage IV adenocarcinoma lung cancer to detect protein death-ligand 1 (PD-L1) expression levels.

Methods

In total, 86 patients with stage IV adenocarcinoma lung cancer underwent ¹⁸F-FDG PET/CT imaging and PD-L1 expression evaluation before treatment from February 2019 to November 2020 at Bach Mai Hospital, Hanoi, Vietnam. The assessed patient characteristics in this study included sex, age, smoking status, epidermal growth factor receptor (EGFR) mutation, PD-L1 expression level, survival status, tumor, node, and metastasis (TNM) stage, and metastasis locations.

Results

The average age was 62.23 ± 9.51 years, and men and women represented 67.4% and 32.6% of the population, respectively. The EGFR mutation rate was 36%. PD-L1 expression was negative (detected in <1% of the tumor) in 40.7% of cases and positive in 59.3% of cases (detected in 1–49% of the tumor in 32.6%; detected in ≥50% of the tumor in 26.7%). The mean maximum standardized uptake value (SUV_max) was 11.09 ± 3.94. SUV_max was significantly higher in PD-L1–positive tumors than in PD-L1–negative tumors (12.24 ± 4.01 and 9.43 ± 3.22, respectively; p = 0.001). Receiver operating characteristic curve analysis revealed an area under the curve of SUVmax was 0.681 (95% confidence interval 0.570–0.793, p = 0.004). Compared with PD-L1–negative cases, SUV_max was significantly different in all PD-L1–positive cases (p = 0.001), weakly PD-L1–positive cases (1–49%, p = 0.005), and strongly PD-L1–positive cases (≥50%, p = 0.003). PD-L1 expression levels were significantly associated with SUV_max (p = 0.001), tumor size (p = 0.022), and EGFR mutation status (p = 0.045).

Conclusions

SUV_max in the primary lesions was able to predict PD-L1 expression and may play a role in predicting PD-L1 immunotherapy efficacy in patients with stage IV lung adenocarcinoma.

Visual Assessment of 18F-FDG Uptake on PET to Predict Survival Benefit to PD-1 Blockade in Non-Small Cell Lung Cancer

BACKGROUND

Programmed death 1 (PD-1) blockade is a standard treatment for patients with metastatic non-small cell lung cancer (NSCLC). Approximately 20% patients receiving PD-1 blockade monotherapy can survive for more than 5 years. However, there are limited data on the optimal biomarkers for predicting long-term outcomes. Therefore, this study aimed to evaluate the prognostic significance of 18F-FDG uptake in patients with NSCLC responding to PD-1 blockade.

PATIENTS AND METHODS

Thirty-eight patients with advanced NSCLC who underwent 18F-FDG PET after confirmation of clinical response to PD-1 blockade monotherapy were retrospectively included in this study. Visual assessment using a 5-point scale score according to 18F-FDG uptake was performed, and the 18F-FDG uptake cutoff score for prolonged response to PD-1 blockade was defined as 3 (low score: 1, 2, or 3 and high score: 4 or 5).

RESULTS

A significantly greater number of patients with low scores had a performance status of 0 or 1 than patients with high scores. Among the 38 patients, 20 (53%) had a low score and 18 (47%) had a high score. Progression-free survival and overall survival were significantly longer in patients with low scores than in patients with high scores. Low 18F-FDG uptake was an independent prognostic factor for predicting favorable progression-free survival and overall survival, as confirmed by multivariate analysis.

CONCLUSIONS

Tumors with lower 18F-FDG uptake on PET than normal hepatic lesions exhibit the possibility of prolonged response to PD-1 blockade. Visual assessment on PET is easy for every clinician and is understandable to confirm aggressive tumor activity.

First Comparison between [18f]-FMISO and [18f]-Faza for Preoperative Pet Imaging of Hypoxia in Lung Cancer

Simple Summary

The definition of the tumor hypoxia is important in oncology because this characteristic is linked to a poor prognosis. In this context, we compared two hypoxia tracers, FMISO and FAZA, before surgery for lung cancer. Hypoxia tracers correlate well with each other and FMISO is superior to FAZA in defining the hypoxia volume of lung cancers. However, there is no correlation with immunohistochemical findings (GLUT-1, CAIX, LDH-5, and HIF1-Alpha).

Abstract

Hypoxic areas are typically resistant to treatment. However, the fluorine-18-fluoroazomycin-arabinoside (FAZA) and fluorine 18 misonidazole (FMISO) tracers have never been compared in non small cell lung cancer (NSCLC). This study compares the capability of 18F-FAZA PET/CT with that of 18F-FMISO PET/CT for detecting hypoxic tumour regions in early and locally advanced NSCLC patients. We prospectively evaluated patients who underwent preoperative PET scans before surgery for localised NSCLC (i.e., fluorodeoxyglucose (FDG)-PET, FMISO-PET, and FAZA-PET). The PET data of the three tracers were compared with each other and then compared to immunohistochemical analysis (GLUT-1, CAIX, LDH-5, and HIF1-Alpha) after tumour resection. Overall, 19 patients with a mean age of 68.2 ± 8 years were included. There were 18 lesions with significant uptake (i.e., SUVmax >1.4) for the F-MISO and 17 for FAZA. The mean SUVmax was 3 (±1.4) with a mean volume of 25.8 cc (±25.8) for FMISO and 2.2 (±0.7) with a mean volume of 13.06 cc (±13.76) for FAZA. The SUVmax of F-MISO was greater than that of FAZA (p = 0.0003). The SUVmax of F-MISO shows a good correlation with that of FAZA at 0.86 (0.66–0.94). Immunohistochemical results are not correlated to hypoxia PET regardless of the staining. The two tracers show a good correlation with hypoxia, with FMISO being superior to FAZA. FMISO, therefore, remains the reference tracer for defining hypoxic volumes.

Combining PD-L1 Expression and Standardized Uptake Values in FDG-PET/CT Can Predict Prognosis in Patients With Resectable Non-Small-Cell Lung Cancer

Background

This study aimed to determine the relationship of programmed death-ligand 1 (PD-L1) expression and standardized uptake values in fluorodeoxyglucose–positron emission tomography/computed tomography (FDG-PET/CT) with prognosis in non–small-cell lung cancer (NSCLC).

Methods

We retrospectively analyzed 328 NSCLC patients who underwent lobectomy/segmentectomy with lymph node dissection. PD-L1 expression was detected by immunohistochemically stained using the murine monoclonal antibody clone 22C3. The preoperative maximum standardized uptake value (SUV_max) of FDG-PET/CT at the primary lesion; pathological factors including histological type, microscopic lymphatic, venous, and pleural invasion; and lymph node metastases in resected specimens was determined. Significant prognostic clinicopathologic factors were analyzed by univariate and multivariate analyses.

Results

PD-L1 expression was higher in men, smokers, squamous cell carcinoma, advanced pathologic stages, positive venous invasion, positive pleural invasion, and high preoperative SUV_max (≥3). Postoperative survival analysis showed that both PD-L1 expression and preoperative SUV_max were significantly negative prognostic factors in univariate analysis for overall survival (OS) (P = 0.0123 and P < 0.0001) and relapse-free survival (RFS) (P = 0.0012 and P < 0.0001). Kaplan–Meier survival curves showed that the OS and RFS were the best in patients with negative PD-L1 expression and SUV_max < 3, intermediate in patients with positive PD-L1 expression and SUV_max < 3 and those with negative PD-L1 expression and SUV_max ≥ 3, and poor in patients with positive PD-L1 expression and SUV_max ≥ 3.

Conclusion

Combining PD-L1 expression and preoperative FDG-PET/CT SUV_max in primary tumor might help in accurate prediction of postoperative prognosis in NSCLC patients.

Tumor immunity is related to 18 F-FDG uptake in thymic epithelial tumor

Background

2‐deoxy‐2‐[fluorine‐18] fluoro‐d‐glucose (¹⁸F‐FDG) positron emission tomography (¹⁸F‐FDG‐PET) is a convenient modality to assess the metabolic activity within tumor cells. However, there is no consensus regarding the relationship between ¹⁸F‐FDG uptake and the immune environment in thymic epithelial tumors (TETs). We conducted a clinicopathological study to elucidate the relationship between ¹⁸F‐FDG uptake and programmed death ligands 1 and 2 (PD‐L1/PD‐L2) expression in patients with TETs. Methods: A total of 108 patients with histologically confirmed TETs classified as thymomas or thymic carcinomas who underwent surgical resection or biopsy or needle biopsy and ¹⁸F‐FDG PET before any treatment between August 2007 and March 2020 were enrolled in this study. Tumor specimens underwent immunohistochemical staining for PD‐L1, PD‐L2, GLUT1, HIF‐1α, VEGFR2, VEGF‐C, and β2 adrenergic receptor. Results: High uptakes of SUV_max, SUV_mean, MTV, and TLG were identified in 28 (25.9%), 61 (56.5%), 55 (50.9%), and 55 (50.9%) of 108 patients, respectively. High uptake of SUV_max significantly correlated with PS (performance status) of 1–2, thymic carcinoma, and advanced stage, and SUV_max on ¹⁸F‐FDG uptake displayed a close association with PD‐L1 and PD‐L2 expressions, but not with MTV and TLG. Our analysis revealed that SUV_max was identified as being significant relationship for positive PD‐L1/PD‐L2 expression. GLUT1, HIF‐1α, and VEGFR2 were significantly associated with the expression of PD‐L1/PD‐L2 from the biological viewpoint.

Conclusion

¹⁸F‐FDG accumulation was closely associated with the expression of PD‐L1/PD‐L2, which, in turn, was correlated with glucose metabolism and hypoxia. PD‐L1/PD‐L2 could affect the glucose metabolism and hypoxia in thymic tumor cells.

The Effect of GLUT1 on Survival Rate and the Immune Cell Infiltration of Lung Adenocarcinoma and Squamous Cell Carcinoma: A Meta and Bioinformatics Analysis

BACKGROUND

Lung adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC) are two major subtypes of non-small cell lung cancer (NSCLC). Studies have shown that abnormal expression of glucose transport type 1 (GLUT1) in NSCLC patients has been associated with progression, aggressiveness, and poor clinical outcome. However, the clinical effect of GLUT1 expression on LUAD and LUSC is unclear.

OBJECTIVE

This study aims to learn more about the character of GLUT1 in LUAD and LUSC.

METHODS

A meta-analysis was performed to evaluate the GLUT1 protein level, and bioinformatics analysis was used to detect the GLUT1 mRNA expression level, survival differences, and the infiltration abundance of immune cells in samples from TCGA. Meanwhile, functional and network analysis was conducted to detect important signaling pathways and key genes with the Gene Expression Omnibus (GEO) dataset.

RESULTS

Our results showed that GLUT1 was over-expressed both in LUAD and LUSC. LUAD patients with high GLUT1 expression had a poor prognosis. Additionally, GLUT1 was related to B cell and neutrophil infiltration of LUAD. In LUSC, GLUT1 was correlated with tumor purity, B cell, CD8⁺ T cell, CD4⁺ T cell, macrophage, neutrophil, and dendritic cell infiltration. The GEO dataset analysis results suggested GLUT1 potentially participated in the p53 signaling pathway and metabolism of xenobiotics by cytochrome P450 and was associated with KDR, TOX3, AGR2, FOXA1, ERBB3, ANGPT1, and COL4A3 gene in LUAD and LUSC.

CONCLUSION

GLUT1 might be a potential biomarker for aggressive progression and poor prognosis in LUAD, and a therapeutic biomarker in LUSC.

Correlation Between Dual-Time-Point FDG PET and Tumor Microenvironment Immune Types in Non-Small Cell Lung Cancer

Purpose

Dual-time-point ¹⁸F-fluorodeoxyglucose positron emission tomography (DTP ¹⁸F-FDG PET), which reflects the dynamics of tumor glucose metabolism, may also provide a novel approach to the characterization of both cancer cells and immune cells within the tumor immune microenvironment (TIME). We investigated the correlations between the metabolic parameters (MPs) of DTP ¹⁸F-FDG PET images and the tumor microenvironment immune types (TMITs) in patients with non-small cell lung cancer (NSCLC).

Methods

A retrospective analysis was performed in 91 patients with NSCLC who underwent preoperative DTP ¹⁸F-FDG PET/CT scans. MPs in the early scan (eSUVmax, eSUVmean, eMTV, eTLG) and delayed scan (dSUVmax, dSUVmean, dMTV, dTLG) were calculated, respectively. The change in MPs (ΔSUVmax, ΔSUVmean, ΔMTV, ΔTLG) between the two time points were calculated. Tumor specimens were analyzed by immunohistochemistry for PD-1/PD-L1 expression and CD8⁺ tumor-infiltrating lymphocytes (TILs). TIME was classified into four immune types (TMIT I ~ IV) according to the expression of PD-L1 and CD8⁺ TILs. Correlations between MPs with TMITs and the immune-related biomarkers were analyzed. A composite metabolic signature (Meta-Sig) and a combined model of Meta-Sig and clinical factors were constructed to predict patients with TMIT I tumors.

Results

eSUVmax, eSUVmean, dSUVmax, dSUVmean, ΔSUVmax, ΔSUVmean, and ΔTLG were significantly higher in PD-L1 positive patients (p = 0.0007, 0.0006, < 0.0001, < 0.0001, 0.0002, 0.0002, 0.0247, respectively), and in TMIT-I tumors (p = 0.0001, < 0.0001, < 0.0001, < 0.0001, 0.0009, 0.0009, 0.0144, respectively). Compared to stand-alone MP, the Meta-Sig and combined model displayed better performance for assessing TMIT-I tumors (Meta-sig: AUC = 0.818, sensitivity = 86.36%, specificity = 73.91%; Model: AUC = 0.869, sensitivity = 77.27%, specificity = 82.61%).

Conclusion

High glucose metabolism on DTP ¹⁸F-FDG PET correlated with the TMIT-I tumors, and the Meta-Sig and combined model based on clinical and metabolic information could improve the performance of identifying the patients who may respond to immunotherapy.

Concordance of PD-L1 Status Between Image-Guided Percutaneous Biopsies and Matched Surgical Specimen in Non-Small Cell Lung Cancer

OBJECTIVE

Programmed death-ligand 1 (PD-L1) expression status is a crucial index for identifying patients who will benefit from anti-programmed cell death protein 1 (PD-1)/PD-L1 therapy for non-small cell lung cancer (NSCLC). However, the concordance of Tumor Proportion Score (TPS) between biopsies and matched surgical specimens remains controversial. This study aims to evaluate the concordance of PD-L1 expression between image-guided percutaneous biopsies and matched surgical specimens.

METHOD

We evaluated 157 patients diagnosed with operable NSCLC on both surgical tissue sections and matched lung biopsies retrospectively. The patients underwent either regular computed tomography (CT)-guided biopsy (n = 82) or positron emission tomography (PET)/CT-guided biopsy (n = 75). The concordance between surgical specimens and lung biopsies for PD-L1 TPS was evaluated using Cohen's kappa (κ) coefficient.

RESULTS

Immunohistochemical expression of PD-L1 was evaluated in both surgical resected specimens and matched biopsies in the eligible 138 patients. The concordance rate of PD-L1 expression between surgical tissue sections and matched biopsies was fairly high at 84.1% (116/138), and the κ value was 0.73 (95% CI: 0.63-0.83, P < 0.001). The concordance rate was higher for tissue sections from PET/CT-guided biopsy than for tissue sections from CT-guided biopsy [88.6% (62/70, κ value: 0.81) vs 79.4% (54/68, κ value: 0.66)].

CONCLUSION

PD-L1 TPS was strongly concordant between surgical specimens and matched lung biopsies. Thus, the routine evaluation of PD-L1 expression in diagnostic percutaneous biopsies could be reliable for identifying patients who will benefit from anti-PD-1/PD-L1 immunotherapy.

Association between 18F-FDG metabolic activity and programmed death ligand-1 (PD-L1) expression using 22C3 immunohistochemistry assays in non-small cell lung cancer (NSCLC) resection specimens

OBJECTIVE

This study sought to investigate the association between ¹⁸F-fludeoxyglucose (¹⁸F-FDG) uptake in positron emission tomography/CT (PET/CT) scans and different programmed death ligand-1 (PD-L1) expression conditions in non-small cell lung cancer (NSCLC).

METHODS

From October 2017 to December 2019, NSCLC was retrospectively identified in 419 consecutive patients who underwent ¹⁸F-FDG PET/CT scans and PD-L1 expression tests using the PD-L1 22C3 assay. The association between clinicopathological characteristics and PD-L1 expression was assessed.

RESULTS

The frequency of PD-L1-positive tumours was 38.2% (160/419) in NSCLC. In NSCLC, the multivariate analysis showed a high maximum standardised uptake value (SUVmax) (p < 0.0001) and an EGFR wild type genotype (p = 0.027) was significantly associated with PD-L1-positivity. In adenocarcinoma (ADC), the multivariate analysis showed that a high SUVmax (p < 0.0001) was significantly associated with PD-L1-positivity. In NSCLC and ADC, a Mann-Whitney U test showed significant differences between groups with PD-L1 high expression and PD-L1 low expression levels in terms of SUVmax (p = 0.011 and p = 0.013, respectively). The results of the receiver operating characteristic curve analysis showed that the area under the curve of the SUVmax was 0.767 (95% CI, 0.720-0.814; p < 0.0001) and 0.712 (95% CI, 0.651-0.774; p < 0.0001) in NSCLC and ADC, respectively.

CONCLUSION

The study demonstrates that the SUVmax was significantly associated with PD-L1 expression in NSCLC and ADC. The SUVmax was significantly different between the PD-L1 high and low expression conditions, as quantified using a PD-L1 22C3 assay.

ADVANCES IN KNOWLEDGE

This study provides direct evidence that SUVmax as a metabolic biomarker may help select patients with NSCLC likely to benefit from pembrolizumab.

Concordance of PD-L1 Status Between Image-Guided Percutaneous Biopsies and Matched Surgical Specimen in Non-Small Cell Lung Cancer

Objective

Programmed death-ligand 1 (PD-L1) expression status is a crucial index for identifying patients who will benefit from anti-programmed cell death protein 1 (PD-1)/PD-L1 therapy for non-small cell lung cancer (NSCLC). However, the concordance of Tumor Proportion Score (TPS) between biopsies and matched surgical specimens remains controversial. This study aims to evaluate the concordance of PD-L1 expression between image-guided percutaneous biopsies and matched surgical specimens.

Method

We evaluated 157 patients diagnosed with operable NSCLC on both surgical tissue sections and matched lung biopsies retrospectively. The patients underwent either regular computed tomography (CT)-guided biopsy (n = 82) or positron emission tomography (PET)/CT-guided biopsy (n = 75). The concordance between surgical specimens and lung biopsies for PD-L1 TPS was evaluated using Cohen’s kappa (κ) coefficient.

Results

Immunohistochemical expression of PD-L1 was evaluated in both surgical resected specimens and matched biopsies in the eligible 138 patients. The concordance rate of PD-L1 expression between surgical tissue sections and matched biopsies was fairly high at 84.1% (116/138), and the κ value was 0.73 (95% CI: 0.63–0.83, P < 0.001). The concordance rate was higher for tissue sections from PET/CT-guided biopsy than for tissue sections from CT-guided biopsy [88.6% (62/70, κ value: 0.81) vs 79.4% (54/68, κ value: 0.66)].

Conclusion

PD-L1 TPS was strongly concordant between surgical specimens and matched lung biopsies. Thus, the routine evaluation of PD-L1 expression in diagnostic percutaneous biopsies could be reliable for identifying patients who will benefit from anti-PD-1/PD-L1 immunotherapy.

Value of 18F-FDG-PET to predict PD-L1 expression and outcomes of PD-1 inhibition therapy in human cancers

Anti-programmed cell death-1 (PD-1)/programmed death ligand-1 (PD-L1) antibodies are administered in varied human cancer types. The expression of PD-L1 within tumor cells has been identified as a predictive marker, although assessing its expression has benefitted only patients with non-small cell lung cancer (NSCLC) or head and neck cancer. Whereas, more than 75% of the patients with NSCLC showing partial response to PD-1 blockade therapy experienced long-term survival for more than 5-years Thus, identifying the responders to PD-1 blockade at early phase after its initiation is of clinical importance. The 2-deoxy-2-[fluorine-18] fluoro-D-glucose (¹⁸F-FDG) on positron emission tomography (PET) can evaluate any tumor shrinkage by assessing the metabolic tumor volume at an earlier phase than conventional modalities such as computed tomography (CT). While several reports describe the correlation of PD-L1 expression with ¹⁸F-FDG uptake rate in the tumor cells, it remains to be delineated whether this rate determined by the glucose metabolism and hypoxia is associated with the status of immune microenvironment, including the expression of PD-L1. Moreover, details of the relationship between expression of PD-L1 and ¹⁸F-FDG uptake is still unclear. Therefore, we reviewed the clinical significance of ¹⁸F-FDG uptake on PET as a predictor of the efficacy of PD-1 blockade therapy, by correlating with the expression of PD-L1, in patients with several neoplasms.

Response evaluation after immunotherapy in NSCLC: Early response assessment using FDG PET/CT

The present study aimed to evaluate the role of early F-18 2-deoxy-2-[fluorine-18] fluoro-D-glucose positron emission tomography/computed tomography (FDG PET/CT) in non-small cell lung cancer patients undergoing immune checkpoint inhibitor (ICI) treatment.Twenty-four non-small cell lung cancer patients who received nivolumab or pembrolizumab and underwent FDG PET/CT as an interim analysis after 2 or 3 cycles of ICI treatment were retrospectively enrolled. Tumor response was assessed using the PET Response Criteria in Solid Tumors 1.0 (PERCIST) and the European Organization for Research and Treatment of Cancer (EORTC) criteria after 2 or 3 cycles of ICI treatment (SCAN-1) and after an additional 2 cycles of ICI treatment (SCAN-2). The best overall response was determined by FDG PET/CT or chest CT at ≥ 3 months after therapy initiation, and the clinical benefit was investigated. progression-free survival was investigated, and its correlation with clinicopathologic and metabolic parameters was examined using a Cox multivariate proportional hazards model.In the interim analysis, 4 patients achieved a complete metabolic response (CMR), 1 patient exhibited a partial metabolic response (PMR), and 14 patients had Progressive metabolic disease (PMD) according to the PERCIST and EORTC criteria. Four patients showed stable metabolic disease (SMD) according to the PERCIST criteria, and 2 patients showed different responses (i.e., PMR) according to the EORTC criteria. Patients with a CMR or PMR at SCAN-1 had a clinical benefit. Among the 4 patients with SMD at SCAN-1, only 1 experienced a clinical benefit regardless of the percent change in the peak standardized uptake value. Two patients with discordant response assessments between the PERCIST and EORTC criteria showed conflicting clinical benefits. Among the 14 patients with PMD, none experienced any clinical benefit. Only metabolic parameters were significant factors for predicting progression in the multivariate analysis (peak standardized uptake value and metabolic tumor volume, HRs of 1.18 and 1.00, respectively).Based on early F-18 FDG PET/CT after ICI treatment, metabolic parameters could predict post-treatment progression. Responses after ICI treatment were correctly assessed in patients with a CMR, a PMR, and PMD, but patients with SMD required a meticulous follow-up because of varying clinical benefits.

Relationship between SP142 PD-L1 Expression and 18F-FDG Uptake in Non-Small-Cell Lung Cancer

Objectives

Immune checkpoint blockers constitute the first-line treatment for advanced non-small-cell lung cancer (NSCLC) with ≥50% PD-L1 expression. In NSCLC, PD-L1 positivity is correlated with high ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake. However, these studies only included patients undergoing surgical resection, almost all in their early stages. Moreover, differences in ¹⁸F-FDG uptake between NSCLC with high (≥50%) and low (49%) PD-L1 expression remain unknown. We aimed to investigate the association between metabolic parameter ¹⁸F-FDG uptake and PD-L1 expression status in NSCLC patients.

Methods

From February 2017 to June 2018, 428 consecutive NSCLC patients who underwent ¹⁸F-FDG positron emission tomography/computed tomography (PET/CT) and SP142 PD-L1 expression analysis were retrospectively assessed. The association between clinicopathological characteristics and PD-L1 expression was examined.

Results

The frequency of PD-L1-positive tumors was 38.1% (163/428), 28.5% (91/319), and 64.2% (61/95) for NSCLC, adenocarcinoma (ADC), and squamous cell carcinoma (SCC), respectively. Maximal standard uptake (SUVmax) was significantly higher in PD-L1-positive than in PD-L1-negative NSCLC (p < 0.0001), ADC (p < 0.0001), and SCC (p=0.006). SUVmax was significantly higher in NSCLC (p=0.001) and ADC (p=0.003) with high rather than low PD-L1 expression. The receiver operating characteristic curve yielded area under the curve values of 0.726 (95% CI, 0.679–0.774, p < 0.0001), 0.694 (95% CI, 0.634–0.755, p < 0.0001), and 0.625 (95% CI, 0.513–0.738, p=0.044) for NSCLC, ADC, and SCC, respectively.

Conclusion

¹⁸F-FDG tumor uptake is strongly, positively correlated with PD-L1 expression in NSCLC and significantly differs between high and low PD-L1-expressing individuals.

Uptake of positron emission tomography tracers reflects the tumor immune status in esophageal squamous cell carcinoma

The relationship between the local immune status and cancer metabolism regarding ¹⁸F‐FDG and ¹⁸F‐FAMT uptake in esophageal squamous cell carcinoma (ESCC) remains unknown. The present study examined the correlations between tumor immune status, clinicopathological factors, and positron emission tomography (PET) tracer uptake in ESCC. Forty‐one ESCC patients who underwent ¹⁸F‐FDG PET and ¹⁸F‐FAMT PET before surgery were enrolled in the study. Immunohistochemistry was conducted for programmed death 1 (PD‐1), CD8, Ki‐67, CD34, GLUT1 (¹⁸F‐FDG transporter) and LAT1 (¹⁸F‐FAMT transporter). ESCC specimens with high tumoral PD‐L1 and high CD8‐positive lymphocytes were considered to have “hot tumor immune status.” High PD‐L1 expression (53.7%) was significantly associated with tumor/lymphatic/venous invasion (P = 0.028, 0.032 and 0.018), stage (P = 0.041), CD8‐positive lymphocytes (P < 0.001), GLUT1 (P < 0.001), LAT1 expression (P = 0.006), Ki‐67 labelling index (P = 0.009) and CD34‐positive vessel counts (P < 0.001). SUVmax of ¹⁸F‐FDG was significantly higher in high PD‐L1 cases than in low PD‐L1 cases (P = 0.009). SUVmax of ¹⁸F‐FAMT was significantly higher in high PD‐L1 (P < 0.001), high CD8 (P = 0.012) and hot tumor groups (P = 0.028) than in other groups. High SUVmax of ¹⁸F‐FAMT (≥4.15) was identified as the only predictor of hot tumor immune status. High PET tracer uptake was significantly associated with cancer aggressiveness and hot tumor immune status in ESCC. PET imaging may be an effective tool to predict tumor immune status in ESCC with respect to immune checkpoint inhibitor sensitivity.

Assessment of associations between clinical and immune microenvironmental factors and tumor mutation burden in resected nonsmall cell lung cancer by applying machine learning to whole-slide images

Background

It is unclear whether clinical factors and immune microenvironment (IME) factors are associated with tumor mutation burden (TMB) in patients with nonsmall cell lung cancer (NSCLC).

Materials and methods

We assessed TMB in surgical tumor specimens by performing whole exome sequencing. IME profiles, including PD‐L1 tumor proportion score (TPS), stromal CD8 tumor‐infiltrating lymphocyte (TIL) density, and stromal Foxp3 TIL density, were quantified by digital pathology using a machine learning algorithm. To detect factors associated with TMB, clinical data, and IME factors were assessed by means of a multiple regression model.

Results

We analyzed tumors from 200 of the 246 surgically resected NSCLC patients between September 2014 and September 2015. Patient background: median age (range) 70 years (39‐87); male 37.5%; smoker 27.5%; pathological stage (p‐stage) I/II/III, 63.5/22.5/14.0%; histological type Ad/Sq, 77.0/23.0%; primary tumor location upper/lower, 58.5/41.5%; median PET SUV 7.5 (0.86‐29.8); median serum CEA (sCEA) level 3.4 ng/mL (0.5‐144.3); median serum CYFRA 21‐1 (sCYFRA) level 1.2 ng/mL (1.0‐38.0); median TMB 2.19/ Mb (0.12‐64.38); median PD‐L1 TPS 15.1% (0.09‐77.4); median stromal CD8 TIL density 582.1/mm² (120.0‐4967.6);, and median stromal Foxp3 TIL density 183.7/mm² (6.3‐544.0).

The multiple regression analysis identified three factors associated with higher TMB: smoking status: smoker, increase PET SUV, and sCEA level: >5 ng/mL (P < .001, P < .001, and P = .006, respectively).

Conclusions

The IME factors assessed were not associated with TMB, but our findings showed that, in addition to smoking, PET SUV and sCEA levels may be independent predictors of TMB. TMB and IME factors are independent factors in resected NSCLC.

18F-FDG maximum standard uptake value predicts PD-L1 expression on tumor cells or tumor-infiltrating immune cells in non-small cell lung cancer

OBJECTIVES

Programmed cell death-ligand 1 (PD-L1) is expressed on tumor cells (TC) and tumor-infiltrating immune cells (IC). We conducted a retrospective study to investigate the relationship between PD-L1 expression on TC/IC and ¹⁸F-FDG uptake in patients with surgically resected non-small cell lung cancer (NSCLC).

METHODS

Total 362 NSCLC patients (297 adenocarcinoma and 65 squamous cell carcinoma) who underwent preoperative ¹⁸F-FDG-PET/CT imaging were analyzed retrospectively. Immunohistochemistry analysis was performed for PD-L1 expression on TC and IC in NSCLC specimens with 28-8 antibody. The cut-off value of 5% for defining PD-L1 positivity was determined according to previous trials. The association between PD-L1 expression and clinicopathological variables were analyzed, including age, gender, smoking status, tumor diameter, lymph node metastasis, stage and the maximum standardized uptake value (SUVmax).

RESULTS

PD-L1 positive expression was 50.8% (184/362) in NSCLC patients. Its positive expression on TC and IC were 24.3% (88/362) and 42.5% (154/362), respectively. SUVmax was significantly higher in patients with PD-L1 positive expression on TC or IC than that with negative. Multivariate analysis demonstrated that PD-L1 expression were correlated with SUVmax. The best cut-off value of SUVmax for PD-L1 expression on TC/IC was 8.5 [area under the curve (AUC) = 0.607, 95% CI 0.549-0.665, P = 0.001, sensitivity 50.5% and specificity 71.4%] determined by ROC curve.

CONCLUSION

High SUVmax is linked to PD-L1 expression on TC and IC in our patients with surgically resected non-small cell lung cancer. ¹⁸F-FDG-PET/CT imaging may be used to predict the PD-L1 expression on TC and IC in NSCLC patients.

The importance of FDG-PET/CT parameters for the assessment of the immune status in advanced HNSCC

OBJECTIVE

Cancer cells secrete large amounts of lactic acid via aerobic glycolysis. We have shown that lactic acid plays an important role as a proinflammatory and immunosuppressive mediator and promotes tumor progression. Fluorine-18 fluorodeoxyglucose (FDG) uptake detected by positron emission tomography/computed tomography (PET/CT) is considered as a good indicator of aerobic glycolysis in cancer. In this study, we examined the relationships between systemic inflammatory parameters and FDG-PET/CT parameters in advanced head and neck squamous cell carcinoma (HNSCC). Furthermore, we investigated the relationships between FDG-PET/CT parameters and M2-macrophage polarization in HNSCC by assessing the ratio of CD163, a M2-macrophage marker, to CD68, a pan-macrophage marker.

METHODS

This study included 73 advanced HNSCC patients. We assessed the C-reactive protein (CRP) level, white blood cell (WBC) count, neutrophil count, lymphocyte count, and monocyte count as systemic inflammatory markers. Additionally, we assessed the maximum standardized uptake value (SUV_max), mean SUV (SUV_mean), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) as FDG-PET/CT parameters.

RESULTS

The CRP level, WBC count, and neutrophil count were correlated with whole-body FDG-PET/CT parameters. The CD163/CD68 ratio was correlated with SUVmax and SUVmean. Our results suggest that systemic inflammation, which is associated with neutrophils, develops in patients with HNSCC having tumors with a larger volume and increased glucose uptake and that M2-macrophage polarization is promoted in HNSCC with increased glucose uptake, SUVmax, and SUVmean. FDG-PET/CT has the potential to reflect cancer-related chronic inflammation and immunosuppressive conditions in cancer patients.

CONCLUSIONS

FDG-PET/CT parameters appear to be useful in assessing the immune status in HNSCC.

Correlation Between von Hippel-Lindau Gene Expression and Tumor SUVmax and Survival Prognosis in Hepatocellular Carcinoma

Background

We investigated the relationship between the 18F-FDG PET/CT metabolic parameter SUVmax in primary hepatocellular carcinoma (HCC) and expression of von Hippel-Lindau (VHL), as well as its effect on HCC survival prognosis.

Material/Methods

We retrospectively analyzed data for 62 HCC patients who received 18F-FDG PET/CT before surgery at the First Affiliated Hospital of Bengbu Medical College from June 2013 to June 2018 (42 males, 20 females; median age 62 years). No treatment was performed prior to the examination. The relationship between preoperative 18F-FDG PET/CT metabolic parameters, clinical pathology, and disease prognosis was analyzed.

Results

SUVmax was significantly different in varying HCC pathological grades, and with tumor length, lymph node metastasis, portal vein tumor thrombus, and distant metastasis (p<0.05). SUVmax was significantly higher in the shorter patient survival group (p<0.05). 18F-FDG uptake was correlated with expression of glucose transporter 1 and VHL in tumor tissues (correlation coefficients 0.476 and 0.565, respectively; both p<0.05). Negative expression of VHL suggested poor tumor differentiation and poor prognosis, but no correlation was observed with patient age, sex, tumor length, lymph node metastasis, or distant metastasis. The survival time of patients with low VHL expression was significantly shorter than that of patients with positive VHL expression (p=0.02).

Conclusions

VHL expression in primary HCC has a significant correlation with SUVmax, and negative VHL expression predicts a worse clinical prognosis.

The efficiency of 18F-FDG PET-CT for predicting the major pathologic response to the neoadjuvant PD-1 blockade in resectable non-small cell lung cancer

PURPOSE

Investigate whether ¹⁸F-FDG PET-CT has the potential to predict the major pathologic response (MPR) to neoadjuvant sintilimab in resectable NSCLC patients, and the potential of sifting patients who probably benefit from immunotherapy.

METHODS

Treatment-naive patients with resectable NSCLC (stage IA-IIIB) received two cycles of sintilimab (200 mg, intravenously, day 1 and 22). Surgery was performed between day 29 and 43. PET-CT was obtained at baseline and prior to surgery. The following lean body mass-corrected metabolic parameters were calculated by PET VCAR: SUL_max, SUL_peak, MTV, TLG, ΔSUL_max%, ΔSUL_peak%, ΔMTV%, ΔTLG%. PET responses were classified using PERCIST. The above metabolic information on FDG-PET was correlated with the surgical pathology. (Registration Number: ChiCTR-OIC-17013726).

RESULTS

Thirty-six patients received 2 doses of sintilimab, all of whom underwent PET-CT twice and had radical resection (35) or biopsy (1). MPR occurred in 13 of 36 resected tumors (36.1%, 13/36). The degree of pathological regression was positively correlated with SUL_max (p = 0.036) of scan-1, and was negatively correlated with all metabolic parameters of scan-2, and the percentage changes of the metabolic parameters after neoadjuvant therapy (p < 0.05). According to PERCIST, 13 patients (36.1%, 13/36) showed partial metabolic response (PMR), 21 (58.3%, 21/36) had stable metabolic disease, and 2 (5.6%, 2/36) had progressive metabolic disease (PMD). There was a significant correlation between the pathological response and the PET responses which were classified using PERCIST. All (100.0%) the PMR (ΔSUL_peak% < - 30.0%) tumors showed MPR.

CONCLUSIONS

¹⁸F-FDG PET-CT can predict MPR to neoadjuvant sintilimab in resectable non-small cell lung cancer.

Immunotherapy by Immune Checkpoint Inhibitors and Nuclear Medicine Imaging: Current and Future Applications

Immunotherapy by using immune checkpoint inhibitors is a revolutionary development in oncology. Medical imaging is also impacted by this new therapy, particularly nuclear medicine imaging (also called radionuclide imaging), which uses radioactive tracers to visualize metabolic functions. Our aim was to review the current applications of nuclear medicine imaging in immunotherapy, along with their limitations, and the perspectives offered by this imaging modality. Method: Articles describing the use of radionuclide imaging in immunotherapy were researched using PubMed by April 2019 and analyzed. Results: More than 5000 articles were analyzed, and nearly 100 of them were retained. Radionuclide imaging, notably 18F-FDG PET/CT, already has a major role in many cancers for pre-therapeutic and therapeutic evaluation, diagnoses of adverse effects, called immune-related adverse events (IrAE), and end-of-treatment evaluations. However, these current applications can be hindered by immunotherapy, notably due to atypical response patterns such as pseudoprogression, which is defined as an increase in the size of lesions, or the visualization of new lesions, followed by a response, and hyperprogression, which is an accelerated tumor growth rate after starting treatment. To overcome these difficulties, new opportunities are offered, particularly therapeutic evaluation criteria adapted to immunotherapy and immuno-PET allowing us to predict responses to immunotherapy. Moreover, some new technological solutions are also promising, such as radiomic analyses and body composition on associated anatomical images. However, more research has to be done, notably for the diagnosis of hyperprogression and pseudoprogression. Conclusion: Immunotherapy, by its major impact on cancer and by the new patterns generated on images, is revolutionary in the field of medical images. Nuclear medicine imaging is already established and will be able to help meet new challenges through its plasticity.

18F-FDG uptake in PET/CT is a potential predictive biomarker of response to anti-PD-1 antibody therapy in non-small cell lung cancer

To examine the association between ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake in positron emission tomography/computed tomography (PET/CT) and the response to anti-programmed cell death-1 (PD-1) monoclonal antibody therapy in non-small cell lung cancer (NSCLC) patients, 89 patients with advanced or recurrent NSCLC were retrospectively analysed. Maximum standardized uptake value (SUVmax) in ¹⁸F-FDG PET/CT and the response to anti-PD-1 antibodies were recorded. A cut-off value of SUVmax was determined by receiver operating characteristic curve analysis for patient stratification. Among the 89 patients evaluated, 24 were classified as responders (all partial response), and 65 as non-responders. The average SUVmax of the responders was 15.60 (range, 6.44–51.10), which was significantly higher than that of the non-responders (11.61; range, 2.13–32.75; P = 0.0168, Student’s t-test). The cut-off SUVmax value selected for stratification was 11.16 (sensitivity and specificity, 0.792 and 0.585, respectively). The response rate of patients with SUVmax value ≥ 11.16 (41.3% [19/46]) was significantly higher than that of patients with SUVmax < 11.16 (11.6% [5/43], P = 0.0012, Chi-squared test). The SUVmax in ¹⁸F-FDG PET/CT is a potential predictive marker of response to anti-PD-1 antibody therapy in NSCLC patients. Further prospective studies of large populations are necessary to validate these results.

Independent expression of circulating and tissue levels of PD-L1: correlation of clusters with tumor metabolism and outcome in patients with non-small cell lung cancer

PURPOSE

To evaluate the clinical-pathological and prognostic significance of the circulating PD-L1 level in patients with surgically treated NSCLC, by combining data for PD-L1 expression with other immune-related markers and tumor metabolism.

METHODS

Overall, 40 patients with resected NSCLC (stage Ia-IIIa) who had preoperative blood storage and underwent staging PET/CT were enrolled for the study. In all cases, we determined plasma levels of PD-L1 (pg/ml), immune-reactive areas (IRA %) covered by CD3, CD68, CD20, CD8, PD-1, and PD-L1 in the tumor specimen, and metabolic parameters on PET, i.e., SUV_max, SUV_peak, metabolic tumor volume (MTV), and total lesion glycolysis (TLG). Variables were statistically analyzed to establish their association with disease-free survival (DFS).

RESULTS

The circulating levels of PD-L1 in the bloodstream could be determined in 38/40 (95%) samples. The mean and median expression levels were 34.86 pg/ml and 24.83 pg/ml, respectively. We did not find any statistically significant correlation between circulating PD-L1 and tissue expression of PD-L1/PD-1. Some mild degree of positive correlation was determined between tissue PD-L1 and SUV_max (ρ = 0.390; p = 0.0148). Hierarchical clustering combining circulating, tissue, and metabolic parameters identified clusters with high metabolic tumor burden or high expression of plasma PD-L1 levels (Z score ≥ 2) as having a poor DFS (p = 0.033). The multivariate analysis detected stage and metabolism (i.e., SUV_max and SUV_peak) as independent prognostic factors for DFS.

CONCLUSION

Plasma levels of PD-L1 are independent of the expression of PD-1/PD-L1 in NSCLC tumor tissue and, when combined with other clinical-pathological parameters, allow for the identification of clusters with different outcomes.

Interdependence of hypoxia and β-adrenergic receptor signaling in pulmonary arterial hypertension

The β-adrenergic receptor (βAR) exists in an equilibrium of inactive and active conformational states, which shifts in response to different ligands and results in downstream signaling. In addition to cAMP, βAR signals to hypoxia-inducible factor 1 (HIF-1). We hypothesized that a βAR-active conformation (R**) that leads to HIF-1 is separable from the cAMP-activating conformation (R*) and that pulmonary arterial hypertension (PAH) patients with HIF-biased conformations would not respond to a cAMP agonist. We compared two cAMP agonists, isoproterenol and salbutamol, in vitro. Isoproterenol increased cAMP and HIF-1 activity, while salbutamol increased cAMP and reduced HIF-1. Hypoxia blunted agonist-stimulated cAMP, consistent with receptor equilibrium shifting toward HIF-activating conformations. Similarly, isoproterenol increased HIF-1 and erythropoiesis in mice, while salbutamol decreased erythropoiesis. βAR overexpression in cells increased glycolysis, which was blunted by HIF-1 inhibitors, suggesting increased βAR leads to increased hypoxia-metabolic effects. Because PAH is also characterized by HIF-related glycolytic shift, we dichotomized PAH patients in the Pulmonary Arterial Hypertension Treatment with Carvedilol for Heart Failure trial (NCT01586156) based on right ventricular (RV) glucose uptake to evaluate βAR ligands. Patients with high glucose uptake had more severe disease than those with low uptake. cAMP increased in response to isoproterenol in mononuclear cells from low-uptake patients but not in high-uptake patients' cells. When patients were treated with carvedilol for 1 wk, the low-uptake group decreased RV systolic pressures and pulmonary vascular resistance, but high-uptake patients had no physiologic responses. The findings expand the paradigm of βAR activation and uncover a novel PAH subtype that might benefit from β-blockers.

Fluorodeoxyglucose uptake is associated with low tumor-infiltrating lymphocyte levels in patients with small cell lung cancer

OBJECTIVES

Positron emission tomography (PET) using 2-deoxy-2-[¹⁸F] fluoro-D-glucose (¹⁸F-FDG) is a clinically useful modality for cancer evaluation. The mechanism of ¹⁸F-FDG uptake within cancer cells involves the glucose transporter 1 (GLUT1) and hypoxia-inducible factor-1 α (HIF-1α). Although recent research has shown its clinical efficacy in small-cell lung cancer (SCLC), no suitable biomarker has been identified. We conducted a clinicopathological study to examine the relationship between tumor immunity and ¹⁸F-FDG uptake in patients with SCLC.

MATERIALS AND METHODS

Tumor sections were stained by immunohistochemistry for GLUT1, HIF-1α, PD-L1, CD4, CD8, and Foxp3. The relationship between clinicopathological features and ¹⁸F-FDG uptake was analyzed. Student's t-test, χ2 test, non-parametric Spearman's rank test, and Kaplan-Meier method were used to evaluate associations between the variables.

RESULTS

A total of 98 patients 78 men and 20 women who underwent ¹⁸F-FDG PET, were enrolled in this study. PD-L1 was expressed in 36.7% (36/98) of all patients; this was significantly associated with GLUT1 expression (p = 0.04). The accumulation of ¹⁸F-FDG was significantly higher in patients with low CD8 and CD4 TILs than in those with high TILs (p = 0.03 and p = 0.01, respectively). The uptake of ¹⁸F-FDG was not significantly associated with the expression of either Foxp3 or PD-L1. Multivariate analysis demonstrated that advanced stage, poor ECOG-PS, and high SUV_max were independent predictors of poor OS. Among patients with limited-stage disease, multivariate analysis confirmed high PD-L1 expression and a high SUV_max to be independent predictors of poor OS. However, only ECOG-PS was found to be an independent predictor of poor OS among patients with extensive-stage tumors.

CONCLUSION

High SUV_max on ¹⁸F-FDG-PET is correlated with low expression of CD8(+) and CD4(+) TILs, but is an independent prognostic factor for OS, particularly in those with limited disease. Further studies are warranted to validate our findings.

Clinicopathologic Features of Thymoma With the Expression of Programmed Death Ligand 1

BACKGROUND

Programmed death ligand 1 (PD-L1) is reportedly expressed in various malignancies and is considered a prognostic factor. We attempted to reveal the usefulness of the PD-L1 expression as a prognostic factor in patients with thymoma.

METHODS

Eighty-one patients with thymoma who underwent surgical resection between 2004 and 2015 were retrospectively reviewed. The PD-L1 expression was evaluated by immunohistochemistry and stratified by the proportion of positive tumor cells. Strong membranous reactivity of the PD-L1 antibody in 1% or more of tumor cells was considered "positive." The association between the PD-L1 expression and the clinicopathologic features was investigated.

RESULTS

The PD-L1 expression was positive in 22 patients (27%) and negative in 59 patients (73%). The PD-L1 positivity was significantly associated with type B2 and B3 thymoma (p < 0.001) and stage III and IV disease (p = 0.048). In addition, PD-L1 positive tumors showed a significantly higher maximum standardized uptake value than PD-L1 negative tumors (p = 0.026). The 5-year disease-free survival rate was 82% in PD-L1 positive patients and 88% in PD-L1 negative patients, showing no significant difference (p = 0.57). Furthermore, PD-L1 positivity was not an independent prognostic factor for the disease-free survival on a Cox proportional hazards analysis (p = 0.59).

CONCLUSIONS

A strong expression of PD-L1 in thymoma was significantly associated with type B2 and B3 and higher pathologic stages. In addition, PD-L1 positivity was associated with an increased maximum standardized uptake value of the tumor. However, patients with PD-L1 positive thymomas did not show a significantly worse prognosis than patients with PD-L1 negative tumors.

Anti PD-1 treatment increases [18F]FDG uptake by cancer cells in a mouse B16F10 melanoma model

Background

Programmed cell death 1 (PD-1) inhibitors act as immune checkpoint inhibitors and are more effective for improving survival time with less toxicity as compared with conventional chemotherapies. In anti PD-1 therapy, it is important to evaluate metabolism in the cancer microenvironment, as this helps to clarify the pathological conditions. Herein, we investigate the early effects of PD-1 therapy on 2-deoxy-2-[¹⁸F]fluoro-d-glucose ([¹⁸F]FDG) uptake in vivo, focusing on cell distribution and glycolysis in both cancer and immune cells.

Results

In a B16F10 melanoma model, [¹⁸F]FDG-positron emission tomography (PET) was performed before treatment and 7 days after the start of treatment. Values were calculated as the percentage-injected activity per gram of tissue (%IA/g). Flow-cytometry was then performed to assess immune cell populations and glucose metabolism. There was a negligible difference in [¹⁸F]FDG uptake between tumors in the treatment group and non-treatment group before the treatment. In contrast, mean [¹⁸F]FDG uptake in the treatment group tumors was significantly higher (8.06 ± 0.48 %IA/g; P = 0.0074) than that in the non-treatment group (4.02 ± 1.03 %IA/g) after anti PD-1 treatment. Assessment of tumor immune cell populations showed that treatment slightly enriched CD8⁺ T cells and CD4⁺ T cells; however, infiltration of immune cells was negligible, and thus, immune cells were not responsible for the increase in [¹⁸F]FDG uptake. On the other hand, anti PD-1 treatment significantly increased glucose transporter 1 (GLUT1) and hexokinase II expression in CD45⁻ cancer cells, indicating that anti PD-1 treatment increased glucose metabolism in cancer cells.

Conclusion

The present study shows that anti PD-1 therapy increases glucose metabolism in cancer cells.

Electronic supplementary material

The online version of this article (10.1186/s13550-018-0433-1) contains supplementary material, which is available to authorized users.