Correlation of metabolic information on FDG-PET with tissue expression of immune markers in patients with non-small cell lung cancer (NSCLC) who are candidates for upfront surgery

The Value of 18F-FDG PET/CT in Predicting the Response to PD-1 Blocking Immunotherapy in Advanced NSCLC Patients with High-Level PD-L1 Expression

BACKGROUND

The objective of this study was to evaluate if ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT)-derived parameters are useful in predicting response and survival after programmed cell death protein 1 (PD-1) blocking immunotherapy in patients with advanced NSCLC characterized by a high programmed death-ligand 1 (PD-L1) expression (≥50%) on immunohistochemistry.

PATIENTS AND METHODS

In 30 patients with advanced stage IV non-small-cell lung cancer (NSCLC) and high PD-L1 expression, ¹⁸F-FDG PET/CT parameters before start of treatment with PD-1 blocking immunotherapy were evaluated retrospectively. In 24 out of the 30 patients, ¹⁸F-FDG PET/CT was available 8 to 9 weeks after start of the treatment. Response Evaluation Criteria in Solid Tumors (RECIST 1.1) and metabolic responses assessed on ¹⁸F-FDG PET/CT were compared.

RESULTS

Median follow-up was 20 months (range, 4.2-37.6). Median PD-L1 expression was 80%. The objective response rate with RECIST 1.1 was 53.3%. Median progression-free survival (PFS) was 12.4 months (95% confidence interval [CI], 1.0-37.8), and median overall survival (OS) was 14.9 months (95% CI, 2.4-38.2). Baseline ¹⁸F-FDG PET/CT parameters did not differ between responders and non-responders (all P > .05). The maximum standardized uptake value (SUVmax) was the only ¹⁸F-FDG PET/CT parameter associated with PFS (P = .04), with a trend for OS (P = .06). At first evaluation, response according to total metabolic tumor volume (TMTV) and total lesion glycolysis (TLG) were associated with PFS and OS (both P < .0001). This was not the case for RECIST 1.1 (P = .29 for PFS and P = .38 for OS).

CONCLUSION

Clinical response and survival were independent from metabolic tumor volume at baseline. Reduction of metabolic tumor volume after 8 to 9 weeks of treatment was a better predictor for prolonged survival than RECIST 1.1.

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.

Stage-Specific PET Radiomic Prediction Model for the Histological Subtype Classification of Non-Small-Cell Lung Cancer

Purpose

To investigate the impact of staging on differences in glucose metabolic heterogeneity between lung adenocarcinoma (ADC) and squamous cell carcinoma (SCC) by ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) textural analysis and to develop a stage-specific PET radiomic prediction model to distinguish lung ADC from SCC.

Patients and Methods

Patients who were histologically diagnosed with lung ADC or SCC and underwent pretreatment ¹⁸F-FDG PET/CT scans were retrospectively identified. Radiomic features were extracted from a semiautomatically outlined tumor region in the Chang-Gung Image Texture Analysis (CGITA) software package. The differences in radiomic parameters between lung ADC and SCC were compared stage-by-stage in 253 consecutive NSCLC patients with stages I to III disease. The least absolute shrinkage and selection operator (LASSO) algorithm was used for feature selection. A radiomic signature for each stage was subsequently constructed and evaluated. Then, an individual nomogram incorporating the radiomic signature and clinical risk factors was established and evaluated. The performance of the constructed models was assessed by receiver operating characteristic (ROC) curve analysis, and the nomogram was further validated by calibration curve analysis.

Results

The performance of the radiomic signature for distinguishing lung ADC and SCC in both the training and validation cohorts was good, with AUCs of 0.883, 0.854, and 0.895 in the training cohort and 0.932, 0.944, and 0.886 in the validation cohort for stages I, II, and III NSCLC, respectively. The radiomic-clinical nomogram integrating radiomic features with independent clinical predictors exhibited more favorable discriminative performance, with AUCs of 0.982, 0.963, and 0.979 in the training cohort and 0.989, 0.984, and 0.978 in the validation cohort for stages I, II, and III, respectively.

Conclusion

Differences in PET radiomic features between lung ADC and SCC varied in different stages. Stage-specific PET radiomic prediction models provided more favorable performance for discriminating the histological subtype of NSCLC.

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.

Molecular imaging in immuno-oncology: current status and translational perspectives

Introduction: Only 20-40% of patients respond to therapy with immune checkpoint inhibitors (ICIs). Therefore, the early identification of subjects that can benefit from such therapeutic regimen is mandatory. Areas covered: The immunobiological mechanisms of ICIs are briefly illustrated. Furthermore, the limitations of traditional radiological approaches are covered. Then, the pros and cons of molecular imaging through positron emission computed tomography (PET/CT) are reviewed, with a particular focus on ¹⁸f-fluorodeoxyglucose (¹⁸F-FDG) and PET-derived metabolic parameters. Lastly, translational perspective of radiopharmaceuticals others than ¹⁸F-FDG such as ⁸⁹zirconium (⁸⁹Zr) or fluorine-18 (¹⁸F) labeled monoclonal antibodies (e.g.⁸⁹Zr-atezolizumab, ⁸⁹Zr-nivolumab) binding to specific biomarkers are discussed. Expert opinion: Molecular imaging presents a prominent role for the management of oncological patients treated with ICIs. Preliminary clinical data indicate that PET/CT with ¹⁸F-FDG is useful for assessing the response to treatment and for the imaging of immune-related adverse effects. Nevertheless, the methodological approach (iPERCIST, PERCIMT, or others) to be used for an optimal diagnostic accuracy and patients' evaluation is still a debated issue. PET/CT with radioligands directed toward ICIs biomarkers, although is still in a translational phase, holds the promise of accurately predicting the response to treatment and revealing the acquired resistance to immunotherapy.

The potential of 18F-FDG PET/CT in predicting PDL1 expression status in pulmonary lesions of untreated stage IIIB-IV non-small-cell lung cancer

OBJECTIVES

To investigate the potential of 2-deoxy-2(¹⁸F)fluoro-d-glucose (¹⁸F-FDG) combined positron emission tomography and computed tomography (PET/CT) in predicting programmed cell death ligand-1 (PDL1) expression status in pulmonary lesions of advanced non-small-cell lung cancer (NSCLC).

MATERIALS AND METHODS

This retrospective study includes 133 untreated stage IIIB-IV NSCLC patients who underwent pulmonary lesion biopsy for PDL1 immunochemistry 1-4 weeks after ¹⁸F-FDG PET/CT scanning, randomly assigned to cohorts for modelling and validation of PDL1 expression predictors. Mean and maximum standard uptake values (pSUVmean and pSUVmax), metabolic tumour volume (pMTV), and total lesion glycolysis (pTLG) of primary lesions were determined. PDL1 expression in pulmonary lesions (pPDL1) was determined using tumour proportion score (TPS), and pPDL1 TPS < 1%, 1-49 %, and ≥ 50 % were considered as pPDL1-negative, pPDL1-moderate, and pPDL1-strong, respectively.

RESULTS

pSUVmean and pSUVmax values were increased with the increase of pPDL1 levels, whereas pMTV and pTLG values were not associated with pPDL1 levels. In the modelling cohort, we found that pSUVmax rather than pSUVmean was an independent predictor for pPDL1-negative, pPDL1-moderate, and pPDL1-strong, whereas pSUVmax < 14.4, 14.4-17.5, and > 17.5 were suggested as predictors for pPDL1-negative, pPDL1-moderate, and pPDL1-strong, respectively (odds ratio: 4.82, 3.92, and 4.45, respectively; P = 0.002, 0.021, and 0.020, respectively). In the validation cohort, pSUVmax < 14.4, 14.4-17.5, and > 17.5 showed significantly high probabilities of being pPDL1-negative, pPDL1-moderate, and pPDL1-strong, respectively (P = 0.006). The accuracies of pSUVmax < 14.4, 14.4-17.5, and > 17.5 predicting pPDL1-negative, pPDL1-moderate, and pPDL1-strong, respectively, in validation cohort, were 66.7 %, 75.8 %, and 84.8 %, respectively.

CONCLUSION

pSUVmax on ¹⁸F-FDG PET/CT is a potential biomarker for pPDL1 TPS < 1%, 1-49 %, and ≥ 50 % in untreated stage IIIB-IV NSCLC, and therefore may be helpful for determining immunotherapeutic strategy for advanced NSCLC.

Assessing Immunotherapy with Functional and Molecular Imaging and Radiomics

Immunotherapy is changing the treatment paradigm for cancer and has introduced new challenges in medical imaging. Because not all patients benefit from immunotherapy, pretreatment imaging should be performed to identify not only prognostic factors but also factors that allow prediction of response to immunotherapy. Follow-up studies must allow detection of nonresponders, without confusion of pseudoprogression with real progression to prevent premature discontinuation of treatment that can benefit the patient. Conventional imaging techniques and classic tumor response criteria are limited for the evaluation of the unusual patterns of response that arise from the specific mechanisms of action of immunotherapy, so advanced imaging methods must be developed to overcome these shortcomings. The authors present the fundamentals of the tumor immune microenvironment and immunotherapy and how they influence imaging findings. They also discuss advances in functional and molecular imaging techniques for the assessment of immunotherapy in clinical practice, including their use to characterize immune phenotypes, assess patient prognosis and response to therapy, and evaluate immune-related adverse events. Finally, the development of radiomics and radiogenomics in these therapies and the future role of imaging biomarkers for immunotherapy are discussed. Online supplemental material is available for this article. ^©RSNA, 2020.

Imaging the Cancer Immune Environment and Its Response to Pharmacologic Intervention, Part 2: The Role of Novel PET Agents

Although ¹⁸F-FDG PET/CT is widely available and is increasingly being used to monitor response to immunotherapy and simultaneously identify immune-related adverse events, there are several challenges in interpreting the results of this investigation, especially early in the course of treatment. It also has limited utility in selecting the optimal type of immunotherapy. As knowledge about immune contexture increases, new targets that may be amenable to imaging are being defined. These exciting advances, coupled with increasingly sophisticated methods for generating radiopharmaceuticals, provide the potential for either replacing or complementing ¹⁸F-FDG PET/CT in the selection and monitoring of immunotherapy. Approaches include imaging specific characteristics of immune cell infiltrates or aspects of the tumor microenvironment that are known to be associated with suppression of the innate and adaptive immune response. Following a large body of preclinical work, promising agents that are entering into early clinical evaluation are discussed. We suggest a speculative algorithm as to how these might be used in routine practice, subject to validation in clinical trials.

Nucleophosmin 1 overexpression correlates with 18F-FDG PET/CT metabolic parameters and improves diagnostic accuracy in patients with lung adenocarcinoma

PURPOSE

This study investigated the correlation of nucleophosmin 1 (NPM1) expression with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computerised tomography scan (PET/CT)-related parameters and compared the diagnostic value of NPM1 with that of the positive biomarker TTF1 in lung adenocarcinoma patients.

METHODS

Forty-six lung adenocarcinoma patients who underwent ¹⁸F-FDG PET/CT before pulmonary surgery were retrospectively analysed. Metabolic parameters including SUV_max, SUV_mean, metabolic tumour volume (MTV) and total lesion glycolysis (TLG) were calculated from ¹⁸F-FDG PET imaging data. The expression levels of NPM1 and TTF1 were assessed using The Cancer Genome Atlas (TCGA) database and immunohistochemistry of tumour tissues and adjacent normal lung tissues. We examined the association between the frequency of NPM1 and TTF1 expression and the metabolic parameters.

RESULTS

Lung adenocarcinoma samples expressed higher levels of NPM1 than adjacent normal lung epithelial tissues. NPM1 showed higher specificity and sensitivity for lung adenocarcinoma compared with TTF1 (p < 0.001). SUV_max, SUV_mean and TLG correlated with NPM1 expression (p < 0.001). MTV was inversely correlated with TTF1 (p < 0.01). SUV_max was the primary predictor of NPM1 expression by lung adenocarcinoma (p < 0.01). A cutoff value for the SUV_max of 3.93 allowed 90.9% sensitivity and 84.6% specificity for predicting NPM1 overexpression in lung adenocarcinoma.

CONCLUSION

NPM1 overexpression correlated with ¹⁸F-FDG PET/CT metabolic parameters and improved diagnostic accuracy in lung adenocarcinoma. SUV_max on ¹⁸F-FDG PET/CT may estimate NPM1 expression for targeted therapy of lung adenocarcinoma.

Recent and Current Advances in FDG-PET Imaging within the Field of Clinical Oncology in NSCLC: A Review of the Literature

Lung cancer is the leading cause of cancer-related deaths around the world, the most common type of which is non-small-cell lung cancer (NSCLC). Computed tomography (CT) is required for patients with NSCLC, but often involves diagnostic issues and large intra- and interobserver variability. The anatomic data obtained using CT can be supplemented by the metabolic data obtained using fluorodeoxyglucose F 18 (FDG) positron emission tomography (PET); therefore, the use of FDG-PET/CT for staging NSCLC is recommended, as it provides more accuracy than either modality alone. Furthermore, FDG-PET/magnetic resonance imaging (MRI) provides useful information on metabolic activity and tumor cellularity, and has become increasingly popular. A number of studies have described FDG-PET/MRI as having a high diagnostic performance in NSCLC staging. Therefore, multidimensional functional imaging using FDG-PET/MRI is promising for evaluating the activity of the intratumoral environment. Radiomics is the quantitative extraction of imaging features from medical scans. The chief advantages of FDG-PET/CT radiomics are the ability to capture information beyond the capabilities of the human eye, non-invasiveness, the (virtually) real-time response, and full-field analysis of the lesion. This review summarizes the recent advances in FDG-PET imaging within the field of clinical oncology in NSCLC, with a focus on surgery and prognostication, and investigates the site-specific strengths and limitations of FDG-PET/CT. Overall, the goal of treatment for NSCLC is to provide the best opportunity for long-term survival; therefore, FDG-PET/CT is expected to play an increasingly important role in deciding the appropriate treatment for such patients.

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.

18F-fluorodeoxyglucose positron emission tomography correlates with tumor immunometabolic phenotypes in resected lung cancer

Enhanced tumor glycolytic activity is a mechanism by which tumors induce an immunosuppressive environment to resist adoptive T cell therapy; therefore, methods of assessing intratumoral glycolytic activity are of considerable clinical interest. In this study, we characterized the relationships among tumor ¹⁸F-fluorodeoxyglucose (FDG) retention, tumor metabolic and immune phenotypes, and survival in patients with resected non-small cell lung cancer (NSCLC). We retrospectively analyzed tumor preoperative positron emission tomography (PET) ¹⁸F-FDG uptake in 59 resected NSCLCs and investigated correlations between PET parameters (SUV_Max, SUV_Total, SUV_Mean, TLG), tumor expression of glycolysis- and immune-related genes, and tumor-associated immune cell densities that were quantified by immunohistochemistry. Tumor glycolysis-associated immune gene signatures were analyzed for associations with survival outcomes. We found that each ¹⁸F-FDG PET parameter was positively correlated with tumor expression of glycolysis-related genes. Elevated ¹⁸F-FDG SUV_Max was more discriminatory of glycolysis-associated changes in tumor immune phenotypes than other ¹⁸F-FDG PET parameters. Increased SUV_Max was associated with multiple immune factors characteristic of an immunosuppressive and poorly immune infiltrated tumor microenvironment, including elevated PD-L1 expression, reduced CD57⁺ cell density, and increased T cell exhaustion gene signature. Elevated SUV_Max identified immune-related transcriptomic signatures that were associated with enhanced tumor glycolytic gene expression and poor clinical outcomes. Our results suggest that ¹⁸F-FDG SUV_Max has potential value as a noninvasive, clinical indicator of tumor immunometabolic phenotypes in patients with resectable NSCLC and warrants investigation as a potential predictor of therapeutic response to immune-based treatment strategies.

FDG uptake reflects breast cancer immunological features: the PD-L1 expression and degree of TILs in primary breast cancer

BACKGROUND

High F18-fluorodeoxyglucose (FDG) uptake has been reported to be a predictor of poor prognosis in patients with breast cancer. We investigated the relationship between FDG uptake and immunological factors, including the data of programmed cell death-ligand 1 (PD-L1), CD8, and tumor-infiltrating lymphocytes (TILs).

METHODS

Breast cancer tissues of 97 patients who underwent surgery without preoperative therapy were examined. The grade of stromal TILs was immunohistochemically evaluated using the criteria of the International TILs Working Group in breast cancer. PD-L1 positivity and CD8 positivity were immunohistochemically evaluated. The FDG uptakes were evaluated based on the standardized uptake value max (SUVmax). The relationships between SUVmax and TIL grade and expression of PD-L1 and CD8 were investigated.

RESULTS

Among the 97 patients, 41 (42.3%) had a high SUVmax in their primary tumor, based on the SUVmax cut-off value 3 yielded by receiver operating characteristic curves. PD-L1 was positive in 17 patients (17.5%). Our analyses revealed that large tumor size, high nuclear grade, high degree of TILs and positive expression of PD-L1 were significantly associated with high SUVmax in the primary tumor. There were significant associations between SUVmax and the degree of TILs (r = 0.428, p < 0.001) and between SUVmax and the PD-L1 positivity (r = 0.413, p < 0.001). All cases with a high degree of TILs showed high CD8 expression.

CONCLUSION

Our results indicate that the FDG uptake may be predictive of immunological features including TILs and PD-L1 expression in breast cancer patients. Additional research is necessary to further evaluate FDG-PET as a biomarker of immune checkpoint therapy in breast cancer.

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.

Retrospective analysis of the prognostic value of PD-L1 expression and 18F-FDG PET/CT metabolic parameters in colorectal cancer

Background: It has been rarely reported whether ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake in colorectal cancer cells is associated with the expression of PD-L1. We performed a clinical pathology study to evaluate PD-L1 expression in patients undergoing surgical resection of colorectal cancer with preoperative ¹⁸F-FDG PET/CT imaging, with the aim of predicting the response of CRC patients to immune checkpoint inhibitors.

Material and Methods: A retrospective analysis of patients with CRC who underwent FDG-PET imaging before surgery was performed to measure the parameters of FDG-PET imaging: the maximum standardized uptake value (SUVmax), the metabolic tumor volume (MTV), and the total lesion glycolysis (TLG) were evaluated to determine whether each parameter was associated with clinical pathology. Tumor specimens were subjected to PD-L1 staining by immunohistochemistry. Analysis of whether there is a correlation between PD-L1 expression and ¹⁸F-FDG uptake parameters in CRC.

Results: PD-L1 expression level was significantly correlated with SUVmax, MTV3.0 and TLG3.0. Multivariate analysis showed that PD-L1 and TLG3.0 were independent predictors of poor DFS in patients with CRC (P=0.009; P=0.016), PD-L1 expression is closely related to the patient's lesion (TLG3.0) (P<0.01).

Conclusion: The results of this study indicate that there was a significant correlation between PD-L1 expression and TLG3.0 which suggested that FDG-PET could serve as a noninvasive tool to assess the tumor microenvironment and as a predictor of PD-L1 inhibitor activity to determine the optimal therapeutic strategy for CRC. High PD-L1 expression levels and high TLG3.0 are independent risk factors for DFS differences in CRC 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.

Comprehensive analysis of the association between tumor glycolysis and immune/inflammation function in breast cancer

Background

Metabolic reprogramming, immune evasion and tumor-promoting inflammation are three hallmarks of cancer that provide new perspectives for understanding the biology of cancer. We aimed to figure out the relationship of tumor glycolysis and immune/inflammation function in the context of breast cancer, which is significant for deeper understanding of the biology, treatment and prognosis of breast cancer.

Methods

Using mRNA transcriptome data, tumor-infiltrating lymphocytes (TILs) maps based on digitized H&E-stained images and clinical information of breast cancer from The Cancer Genome Atlas projects (TCGA), we explored the expression and prognostic implications of glycolysis-related genes, as well as the enrichment scores and dual role of different immune/inflammation cells in the tumor microenvironment. The relationship between glycolysis activity and immune/inflammation function was studied by using the differential genes expression analysis, gene ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, gene set enrichment analyses (GSEA) and correlation analysis.

Results

Most glycolysis-related genes had higher expression in breast cancer compared to normal tissue. Higher phosphoglycerate kinase 1 (PGK1) expression was associated with poor prognosis. High glycolysis group had upregulated immune/inflammation-related genes expression, upregulated immune/inflammation pathways especially IL-17 signaling pathway, higher enrichment of multiple immune/inflammation cells such as Th2 cells and macrophages. However, high glycolysis group was associated with lower infiltration of tumor-killing immune cells such as NKT cells and higher immune checkpoints expression such as PD-L1, CTLA4, FOXP3 and IDO1.

Conclusions

In conclusion, the enhanced glycolysis activity of breast cancer was associated with pro-tumor immunity. The interaction between tumor glycolysis and immune/inflammation function may be mediated through IL-17 signaling pathway.

The immune-metabolic-prognostic index and clinical outcomes in patients with non-small cell lung carcinoma under checkpoint inhibitors

PURPOSE

This prospective study evaluated whether peripheral blood biomarkers and metabolic parameters on F-18 fludeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) could be associated with clinical outcome in non-small cell lung carcinoma (NSCLC) patients treated with immune checkpoint inhibitors (ICI).

METHODS

Data from 33 patients with NSCLC and treated with ICI were collected. Complete blood cell counts before and at the first restaging were measured. All patients underwent F-18 FDG PET/CT at baseline, while 25 patients at the first restaging. Progression-free survival (PFS) and overall survival (OS) were determined and compared using the Kaplan-Meier and the log-rank test. The median follow-up was 11.3 months (range 1-17 months).

RESULTS

Multivariate analyses demonstrated that low neutrophil-to-lymphocyte ratio (NLR < 4.9) and low total lesion glycolysis (TLG < 541.5 ml) at the first restaging were significantly associated with PFS (both p = 0.019) and OS (p = 0.001 and p = 0.048, respectively). An immune-metabolic-prognostic index (IMPI), based on post-NLR and post-TLG was developed, categorizing 3 groups: high risk, 2 factors; intermediate risk, 1 factor; low risk, 0 factors. Median PFS for low, intermediate and high risk was 7.8 months (95% CI 4.6-11.0), 5.6 months (95% CI 3.8-7.4), and 1.8 months (95% CI 1.6-2.0) (p < 0.001) respectively. Likewise, median OS was 15.2 months (95% CI 10.9-19.6), 13.2 months (95% CI 5.9-20.3), and 2.8 months (95% CI 1.4-4.2) (p < 0.001), respectively.

CONCLUSION

IMPI at the first restaging, combining both inflammatory and metabolic biomarkers, was correlated with PFS and OS. IMPI can be a potentially valuable tool for identifying NSCLC patients who are likely to benefit from ICI.

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.

Correlation between 18F-FDG uptake on PET/MRI and the level of tumor-infiltrating lymphocytes (TILs) in triple-negative and HER2-positive breast cancer

PURPOSE

The tumor microenvironment is related to the metabolism of cancer cells and local immune reactions. Previous studies have established TILs could be a significant prognostic factor, especially for triple-negative breast cancers (TNBC) and human epithelial growth factor receptor 2 (HER2)-positive breast cancers. We explore the association between metabolic information on PET/MRI with TILs in TNBC and HER2-positive breast cancer.

METHOD

We retrospectively reviewed the cases of 55 women with triple-negative or HER2-positive invasive ductal carcinomas who had undergone ¹⁸F-FDG PET/MRI without neo-adjuvant treatment for pre-operative evaluation. FDG uptake was quantified as standardized uptake value (SUV) max. The existence of peritumoral edema on PET/MRI was also recorded. The TIL score of the breast cancers was defined histologically on the basis of the proportion of the area infiltrated by lymphocytes, and classified as low (<10 %), intermediate (10-50 %), and high (>50 %). The association between PET/MRI findings and TILs was assessed using Kruskal-Wallis test and Wilcoxon signed-rank test.

RESULTS

There were 14 high TIL, 20 intermediate TIL and 21 low TIL lesions. Higher values of SUVmax were found in the high and intermediate TIL group as compared to the low TIL group (P = 0.013). On the other hand, the lesions with peritumoral edema in the low TIL group tended to show high SUVmax (P = 0.014).

CONCLUSIONS

¹⁸F-FDG uptake on PET/MRI correlated with TIL levels in patients with TNBC and HER2-positive breast cancer. This finding suggests that preoperative PET/MRI may be useful as a non-invasive tool for guiding the treatment plan.

Hyperprogressive Disease in Patients with Non-Small Cell Lung Cancer Treated with Checkpoint Inhibitors: The Role of 18F-FDG PET/CT

A new pattern of response, so-called hyperprogressive disease (HPD), is emerging during treatment with immune checkpoint inhibitors (ICIs). Our aim was to investigate the prevalence of such a phenomenon and to assess its association with clinical variables and metabolic parameters by ¹⁸F-FDG PET/CT. Methods: Data from 50 patients (34 men and 16 women; median age, 73 y) with non-small cell lung carcinoma treated with ICIs were prospectively collected. All patients underwent contrast-enhanced CT, ¹⁸F-FDG PET/CT, and complete peripheral blood sampling at baseline before ICI treatment. HPD was defined according to clinical and radiologic criteria. Because of rapid disease progression or worsening of clinical condition, radiologic response assessment was available for only 46 of the 50 patients. Overall survival (OS) was analyzed using the Kaplan-Meier method and the log-rank test. A Cox proportional hazards regression analysis was used to evaluate factors independently associated with OS. Median follow-up was 12.4 mo (range, 9.7-15.2 mo). Results: We identified the following response categories: 10 cases as complete or partial response, 17 cases as stable disease, 5 cases as progressive disease, and 14 cases as HPD. Among metabolic parameters, we observed a statistically significant association between HPD status and tumor burden, expressed by both TLG (756.1 cm³ for HPD vs. 475.6 cm³ for non-HPD, P = 0.042) and MTV (287.3 for HPD vs. 62.1 for non-HPD, P = 0.011). Among clinical variables, 12 of 14 patients (85.7%) within the HPD group, compared with 8 of 32 patients (25%) in the non-HPD group, had more than 2 metastatic sites (P < 0.001). In addition, the derived neutrophil-to-lymphocyte ratio and platelet count were significantly associated with HPD status (P = 0.038 and P = 0.025, respectively). Survival analysis showed a median OS of 4 mo for the HPD group, compared with 15 mo for the non-HPD group (P = 0.003). Likewise, median OS was significantly different when we considered all the response categories: complete or partial response, stable disease, progressive disease, and HPD (P = 0.001). Finally, multivariate analysis identified metabolic tumor volume and derived neutrophil-to-lymphocyte ratio as independent predictors for OS. Conclusion: Our results suggest that the use of ICIs might represent a concern in patients with high metabolic tumor burden and inflammatory indices at baseline. However, additional studies are needed.

Relationship between PD-L1 expression and 18F-FDG uptake in gastric cancer

PURPOSE

Immunotherapy has been successfully utilized for treatment of gastric cancer, so the identification of clinicopathologic features that are predictive of response to this therapy is crucial. ¹⁸F-FDG PET/CT can provide information on the molecular phenotype of many malignant tumors. The correlation between ¹⁸F-FDG accumulation and PD-L1/PD-L1-TILs status in gastric cancer patients has not been investigated. The aim of the current study is to assess whether ¹⁸F-FDG accumulation is associated with PD-L1/PD-L1-TILs status, and whether ¹⁸F-FDG PET/CT may be useful for predicting PD-L1/PD-L1-TILs expression of gastric cancer.

RESULTS

Tumors with positive PD-L1 expression had higher SUVmax than in tumors with negative PD-L1 expression (15.0 ± 8.0 vs. 7.2 ± 4.2, respectively; P = 0.004). Tumors with positive PD-L1-TILs expression also had higher SUVmax than in tumors with negative PD-L1-TILs expression (10.3 ± 6.5 vs. 6.6 ± 3.7, respectively; P = 0.034). Multivariate analysis suggested that SUVmax remained significantly correlated with the status of PD-L1 (P = 0.043) and PD-L1-TILs (P = 0.016). PD-L1 expression was predicted with an accuracy of 67.2% when a SUVmax value of 8.55 was used as a cutoff point for analysis. Similarly, PD-L1-TILs expression was predicted with an accuracy of 64.2%, when a SUVmax value of 7.9 was used as the threshold for analysis.

CONCLUSION

Higher ¹⁸F-FDG accumulation in gastric cancers is correlated with positive PD-L1/PD-L1-TILs expression. ¹⁸F-FDG PET/CT may be used to predict the status of PD-L1/PD-L1-TILs and thus aid in optimal treatment decision.

METHODS

A retrospective analysis was conducted on 64 patients with gastric cancer who underwent ¹⁸F-FDG PET/CT. SUVmax was calculated from the ¹⁸F-FDG accumulation of the primary tumor. The relationship between SUVmax and PD-L1/PD-L1-TILs status was analyzed.

18F-FDG PET/CT in non-small-cell lung cancer patients: a potential predictive biomarker of response to immunotherapy

AIM

The aim of this study was to assess the predictive role of fluorine-18-fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) in the evaluation of response to immunotherapy in patients affected by metastatic lung cancer.

MATERIALS AND METHODS

From a single-center database, data for 32 patients (median age: 69 years; range: 37-78) with metastatic lung cancer were retrospectively retrieved. All patients were treated with nivolumab. PD-L1 expression was available in 19/32 patients. All patients underwent F-FDG PET/CT before immunotherapy. Whole-body maximum standardized uptake value (SUVmaxwb), metabolic tumor volume (MTVwb), and total lesion glycolysis (TLGwb) were obtained as the sum of SUVmax, metabolic tumor volume, and total lesion glycolysis in all metabolic lesions. The best response to therapy was considered in terms of partial response (PR), stable disease (SD), and progressive disease (PD) on the basis of clinical and radiological follow-up.

RESULTS

F-FDG PET/CT was positive in 30/32 (94%) patients. The majority of them had a pathological F-FDG uptake in the lung, lymph nodes, and bones. SUVmaxwb, MTVwb, and TLGwb were higher in patients with a positive PD-L1 expression than those with negative expression. Twenty-one patients achieved disease control (PR+SD), whereas 11 did not (PD). SUVmaxwb was significantly higher in patients without a response to therapy than those with a response to immunotherapy (median: 48.97 vs. 20.85; Student t-test: P = 0.002). Similarly, TLGwb and MTVwb were also higher in nonresponders than responders, although not statistically significant. However, the difference was more evident in women than men (median SUVmaxwb in responders and nonresponders for women and men: 17.86 vs. 85.89 and 21.38 vs. 44.38, respectively).

CONCLUSION

The entire tumor burden evaluated by F-FDG PET/CT can be predictive of response to immunotherapy in patients with metastatic lung cancer. A large prospective multicenter trial is warranted to definitively assess the usefulness of F-FDG PET/CT as a predictive biomarker of response to immunotherapy.

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.

New insight on the correlation of metabolic status on 18F-FDG PET/CT with immune marker expression in patients with non-small cell lung cancer

BACKGROUND

Metabolic information obtained through ¹⁸F-flurodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) is used to evaluate malignancy by calculating the glucose uptake rate, and these parameters play important roles in determining the prognosis of non-small cell lung cancer (NSCLC). The expression of immune-related markers in tumor tissue reflects the immune status in the tumor microenvironment. However, there is lack of reports on the association between metabolic variables and intra-tumor immune markers. Herein, we investigate the correlation between metabolic status on ¹⁸F-FDG PET/CT and intra-tumor immunomarkers' expression in NSCLC patients.

METHODS

From April 2008 to August 2014, 763 patients were enrolled in the analysis to investigate the role of maximum standardized uptake value (SUVmax) in lung cancer. One hundred twenty-two tumor specimens were analyzed by immunohistochemistry (IHC) to intra-tumor immune cells and programmed death protein ligand 1(PD-L1) expression on tumor cells. The correlation between metabolic variables and the expression of tissue immune markers were analyzed.

RESULTS

SUVmax values have significant variations in different epidermal growth factor receptor (EGFR) statuses (wild type vs mutant type), high/low neutrophil-to-lymphocyte ratio (NLR) groups, and high/low platelets-to-lymphocyte ratio (PLR) groups (p < 0.001, p < 0.001, p = 0.003, respectively). SUVmax was an independent prognostic factor in lung cancer patients (p = 0.013). IHC demonstrated a statistically significant correlation between SUVmax and the expression of CD8 tumor-infiltrating lymphocytes (p = 0.015), CD163 tumor-associated macrophages (TAMs) (p = 0.003), and Foxp3-regulatory T cells (Tregs) (p = 0.004), as well as PD-1 and PD-L1 (p = 0.003 and p = 0.012, respectively). With respect to patient outcomes, disease stage, BMI, SUVmax, metabolic tumor volume (MTV), TLG (tumor lesion glycolysis), CD163-TAMs, CD11c-dendritic cells (DCs), PD-L1, and Tregs showed a statistically significant correlation with progression-free survival (PFS) (p < 0.001, 0.023, < 0.001, 0.007, 0.005, 0.004, 0.008, 0.048, and 0.014, respectively), and disease stage, SUVmax, MTV, TLG, CD163-TAMs, CD11c-DCs, and PD-L1 showed a statistically significant correlation with overall survival (OS) (p < 0.001, < 0.001, 0.014, 0.012, < 0.001, 0.001, and < 0.001, respectively).

CONCLUSION

This study revealed an association between metabolic variable and immune cell expression in the tumor microenvironment and suggests that SUVmax on ¹⁸F-FDG PET/CT could be a potential predictor for selecting candidates for immunotherapy.

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.

Prognostic and theranostic 18F-FDG PET biomarkers for anti-PD1 immunotherapy in metastatic melanoma: association with outcome and transcriptomics

PURPOSE

An imaging-based stratification tool is needed to identify melanoma patients who will benefit from anti Programmed Death-1 antibody (anti-PD1). We aimed at identifying biomarkers for survival and response evaluated in lymphoid tissue metabolism in spleen and bone marrow before initiation of therapy.

METHODS

This retrospective study included 55 patients from two institutions who underwent 18F-FDG PET/CT before anti-PD1. Parameters extracted were SUVmax, SUVmean, HISUV (SUV-based Heterogeneity Index), TMTV (total metabolic tumor volume), TLG (total lesion glycolysis), BLR (Bone marrow-to-Liver SUVmax ratio), and SLR (Spleen-to-Liver SUVmax ratio). Each parameter was dichotomized using the median as a threshold. Association with survival, best overall response (BOR), and transcriptomic analyses (NanoString assay) were evaluated using Cox prediction models, Wilcoxon tests, and Spearman's correlation, respectively.

RESULTS

At 20.7 months median follow-up, 33 patients had responded, and 29 patients died. Median PFS and OS were 11.4 (95%CI 2.7-20.2) and 28.5 (95%CI 13.4-43.8) months. TMTV (>25cm³), SLR (>0.77), and BLR (>0.79) correlated with shorter survival. High TMTV (>25 cm3), SLR (>0.77), and BLR (>0.79) correlated with shorter survival, with TMTV (HR PFS 2.2, p = 0.02, and HR OS 2.5, p = 0.02) and BLR (HR OS 2.3, p = 0.04) remaining significant in a multivariable analysis. Low TMTV and TLG correlated with BOR (p = 0.03). Increased glucose metabolism in bone marrow (BLR) was associated with transcriptomic profiles including regulatory T cell markers (p < 0.05).

CONCLUSION

Low tumor burden correlates with survival and objective response while hematopoietic tissue metabolism correlates inversely with survival. These biomarkers should be further evaluated for potential clinical application.

The relationship between ring-type dedicated breast PET and immune microenvironment in early breast cancer

PURPOSE

¹⁸F-fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET) is related to the biological parameters and prognosis of breast cancer. However, whether whole-body PET (WBPET) and dedicated breast PET (DbPET) can reflect the tumor microenvironment is unclear. This study investigated the relationship between stromal tumor-infiltrating lymphocytes (TILs) and maximum standardized uptake value (SUVmax) in WBPET and DbPET.

METHODS

A total of 125 invasive breast cancers underwent WBPET and ring-type DbPET and resected specimens were pathologically assessed. The impact of SUVmax on the tumor biological parameters and TILs was retrospectively evaluated. SUVmax was classified as high and low relative to the median values (WBPET-SUVmax: 2.2 and DbPET-SUVmax: 6.0).

RESULTS

SUVmax correlated with tumor size, nuclear grade, Ki-67 labeling index, and TILs in both WBPET and DbPET (all p < 0.001). In multiple linear regression analysis, tumor size, Ki-67 labeling index, and TILs predicted SUVmax in WBPET and DbPET. The cutoff values of tumor size, Ki-67 labeling index, and TILs predicting high SUVmax were 20 mm, 20%, and 20%, respectively. In multivariate analysis, the predictive factors for high SUVmax were tumor size and Ki-67 labeling index for WBPET and tumor size and TILs for DbPET. High SUVmax in DbPET was related to high numbers of TILs after propensity score matching analysis; however, WBPET was not (p = 0.007 and p = 0.624, respectively).

CONCLUSIONS

Both SUVmax values in WBPET and DbPET predicted TIL concentration of the primary breast cancer. In DbPET, SUVmax represented the immune microenvironment after adjusting for tumor biological factors.

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.

Dynamic FDG-PET/CT in the Initial Staging of Primary Breast Cancer: Clinicopathological Correlations

Our aim was to evaluate correlation between clinicopathological features (clinical T and clinical N stages; histological type; nuclear grade; hormone-receptor and HER2 status, proliferation activity and tumor subtypes) of breast cancer and kinetic parameters measured by staging dynamic FDG-PET/CT examinations. Following ethical approval and patients’ informed consent we included 34 patients with 35 primary breast cancers in our prospective study. We performed dynamic PET imaging, and assessed plasma activity noninvasively. To delineate primary tumors we applied a frame-by-frame semi-automatic software-based correction of motion artefacts. FDG two-compartment kinetic modelling was applied to assess K1, k2, k3 rate coefficients and to calculate Ki (tracer flux constant) and MRFDG (FDG metabolic rate). We found that k3, Ki and MRFDG were significantly higher in higher grade (p = 0.0246, 0.0089 and 0.0076, respectively), progesterone-receptor negative (p = 0.0344, 0.0217 and 0.0132) and highly-proliferating (p = 0.0414, 0.0193 and 0.0271) tumors as well as in triple-negative and hormone-receptor negative/HER2-positive subtypes (p = 0.0310, 0.0280 and 0.0186). Ki and MRFDG were significantly higher in estrogen-receptor negative tumors (p = 0.0300 and 0.0247, respectively). Ki was significantly higher in node-positive than in node-negative disease (p = 0.0315). None of the assessed FDG-kinetic parameters showed significant correlation with stromal TIL. In conclusion, we confirmed a significant relationship between kinetic parameters measured by dynamic PET and the routinely assessed clinicopathological factors of breast cancer: high-grade, hormone-receptor negative tumors with high proliferation rate are characterized by higher cellular FDG-uptake and FDG-phosphorylation rate. Furthermore, we found that kinetic parameters based on the dynamic examinations are probably not influenced by stromal TIL infiltration.

Predictors of metabolic response in propensity-matched lymphoma patients on interim 18F-fluorodeoxyglucose positron-emission tomography/computed tomography using standardized imaging and reporting protocol: Do we really have one?

The purpose of this prospective study was to determine metabolic response predictor(s) in propensity-matched patients having lymphomas who had baseline and interim ¹⁸fluorodeoxyglucose (FDG) positron-emission tomography/computed tomography (PET/CT) using strict standardized imaging and reporting protocols. This prospective study was conducted at PET/CT section of a JCI-accredited healthcare facility from April 2017 to February 2018. Patients with baseline and interim ¹⁸FDG PET/CT scans using standardized protocol were selected. Interim scans were performed not earlier than 2^nd or later than 4^th chemotherapy. During the study period, 97 of 112 consecutive patients with lymphomas (Hodgkin-HL: 32/97 and Non-Hodgkin-NHL: 65/97) were included in the study. Mean age of cohort was 45 ± 19 years (71% male and 29% female) having a mean body mass index (BMI) of 25.57 ± 5.54 Kg/m² having Stage I (21%), Stage II (18%), Stage III (16%), and Stage IV (45%) disease. Bulky disease was found in 14% and ¹⁸FDG-avid marrow deposits in 33%. Standardized PET/CT imaging protocol as per EANM guidelines was strictly adopted for baseline and interim studies. %Δ changes in fasting blood sugar, ¹⁸FDG dose, uptake time, and liver SUV mean were 3.96%, 2.83%, 2.49%, and 12.15%, respectively. Based on Deauville's scoring, cohort was divided into responders having Score 1-3 (49/97) and nonresponders having Score 4-5 (48/97). The demographic analysis found no significant difference between responders and nonresponders for age, gender, BMI, staging, bulky disease or marrow involvement, and study protocol. No significant coefficient or odd ratios were found on multivariate analysis for age, gender, maximum standardized uptake value (SUV_max), size, BMI, NHL, and advance disease (Stage III and IV) in both groups (χ²: 5.12; receiver operating characteristic [95% confidence interval]: 0.616 [0.51-0.713]; P =0.528). Among responders, baseline SUV_max and tumor size had a direct correlation with a metabolic response on iPET, more pronounced in NHL than HL groups (SUV_max: 13.4 vs. 19.5 and size: 52 vs. 87 mm; P < 0.0001). We conclude that no significant predictor was found for response in propensity-matched patients with lymphomas (both HL and NHL) who had baseline and interim PET/CTs acquired with a standardized protocol. However, NHL responders were found to have higher baseline median SUV_max and larger lesion size as compared to HL responders. Although, these data are not in concordance with published findings but need to be validated with larger studies using standardized imaging and reporting protocols in propensity-matched patients with lymphomas.

FDG PET/CT for assessing tumour response to immunotherapy : Report on the EANM symposium on immune modulation and recent review of the literature

This paper follows the immunotherapy symposium held during the European Association of Nuclear Medicine (EANM) 2017 Annual Congress. The biological basis of the immune checkpoint inhibitors and the drugs most frequently used for the treatment of solid tumours are reviewed. The issues of pseudoprogression (frequency, timeline), hyperprogression and immune-related side effects are discussed, as well as their implications for patient management. A review of the recent literature on the use of FDG PET for assessment of immunotherapy is presented, and recommendations are provided for assessing tumour response and reporting immune-related side effects with FDG PET based on published data and experts' experience. Representative clinical cases are also discussed.

Tumor heterogeneity, hypoxia, and immune markers in surgically resected non-small-cell lung cancer

OBJECTIVES

This study aimed to determine the prognostic role of textural features and their association with metabolic parameters, hypoxia, and cancer-related immune markers in non-small-cell lung cancer (NSCLC) patients.

PATIENTS AND METHODS

The trial was registered at http://www.clinicaltrials.gov (NCT02519062). From January 2010 to May 2014, 44 patients (male : female=33 : 11; median age: 69.5 years), referred to our Institution for NSCLC resection, were enrolled. Tumor specimens were assessed for HIF-1α, CD68-TAMs, CD8-TILs, PD-1-TILs, and PD-L1 expressions. All patients underwent fluorine-18-fluorodeoxyglucose (F-FDG) PET before surgery. Semiquantitative parameters included maximum standardized uptake value (SUVmax), SUVpeak, SUVmean, metabolic tumor volume, and total lesion glycolysis, whereas for heterogeneity, we considered tumor sphericity, skewness, kurtosis, entropy, and energy. Parameters were correlated with disease-free survival (DFS) considering a median follow-up of 22.7 months.

RESULTS

SUVmax (cutoff: 7.9; P=0.015), SUVpeak (cutoff: 6.7; P=0.013), SUVmean (cutoff: 5.5; P=0.028), metabolic tumor volume (cutoff: 3.6 cm; P=0.027), and entropy (cutoff: 1.89; P=0.045) showed a statistically significant association with DFS. Also, a high expression of cytoplasmic HIF-1α (score 3) was associated with DFS (hazard ratio: 0.09; P=0.003). All F-FDG PET variables differed significantly in tumors with high or low entropy (≤1.89). Also, a significantly higher level of mean CD8-TILs was observed in tumors with higher entropy (P=0.041).Using identified prognostic factors, we developed a scoring system, which was confirmed to be associated with DFS (P<0.004). On receiver operating characteristics analysis, a score above 3 was defined as the optimal cutoff point.

CONCLUSION

Tumor heterogeneity, metabolic parameters, and high expression of hypoxia were found to be prognostic factors in NSCLC patients who were candidates for surgery. Higher levels of entropy appear to be associated with increased density of CD8-TILs. The combination of investigated prognostic factors enabled the development of a potential scoring system associated with DFS.