Primary tumor standardized uptake value measured on F18-Fluorodeoxyglucose positron emission tomography is of prediction value for survival and local control in non-small-cell lung cancer receiving radiotherapy: meta-analysis

Tumor metabolic activity is associated with subcutaneous adipose tissue radiodensity and survival in non-small cell lung cancer

BACKGROUND

Cachexia-associated body composition alterations and tumor metabolic activity are both associated with survival of cancer patients. Recently, subcutaneous adipose tissue properties have emerged as particularly prognostic body composition features. We hypothesized that tumors with higher metabolic activity instigate cachexia related peripheral metabolic alterations, and investigated whether tumor metabolic activity is associated with body composition and survival in patients with non-small-cell lung cancer (NSCLC), focusing on subcutaneous adipose tissue.

METHODS

A retrospective analysis was performed on a cohort of 173 patients with NSCLC. 18F-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) scans obtained before treatment were used to analyze tumor metabolic activity (standardized uptake value (SUV) and SUV normalized by lean body mass (SUL)) as well as body composition variables (subcutaneous and visceral adipose tissue radiodensity (SAT/VAT radiodensity) and area; skeletal muscle radiodensity (SM radiodensity) and area). Subjects were divided into groups with high or low SAT radiodensity based on Youden Index of Receiver Operator Characteristics (ROC). Associations between tumor metabolic activity, body composition variables, and survival were analyzed by Mann-Whitney tests, Cox regression, and Kaplan-Meier analysis.

RESULTS

The overall prevalence of high SAT radiodensity was 50.9% (88/173). Patients with high SAT radiodensity had shorter survival compared with patients with low SAT radiodensity (mean: 45.3 vs. 50.5 months, p = 0.026). High SAT radiodensity was independently associated with shorter overall survival (multivariate Cox regression HR = 1.061, 95% CI: 1.022-1.101, p = 0.002). SAT radiodensity also correlated with tumor metabolic activity (SULpeak rs = 0.421, p = 0.029; SUVpeak rs = 0.370, p = 0.048). In contrast, the cross-sectional areas of SM, SAT, and VAT were not associated with tumor metabolic activity or survival.

CONCLUSION

Higher SAT radiodensity is associated with higher tumor metabolic activity and shorter survival in patients with NSCLC. This may suggest that tumors with higher metabolic activity induce subcutaneous adipose tissue alterations such as decreased lipid density, increased fibrosis, or browning.

When to Consider Invasive Lymph Node Staging in Non-Small-Cell Lung Cancer? A Novel Scoring System Utilising Metabolic Parameters in 18F-FDG PET/CT

OBJECTIVE

The maximum standardised uptake value (SUVmax) is a widely utilised metric in positron emission tomography/computed tomography for clinically staging non-small-cell lung cancer (NSCLC), yet the reliability of SUVmax remains controversial. We herein aimed to assess the effectiveness of semi-quantitative parameters, encompassing size, SUVmax, metabolic tumour volume (MTV), total lesion glycolysis (TLG) and heterogeneity factor (HF), in evaluating both primary tumours and lymph nodes (LNs) on positron emission tomography/computed tomography. A novel scoring system was devised to appraise the role of semi-quantitative parameters and visually evaluate LNs for nodal staging.

MATERIALS AND METHODS

Patients with pathological NSCLC, diagnosed between 2014 and 2019 and clinically staged I-III, were enrolled in the study. Patient demographics, including age, sex, tumour location, diameter, tumour-node-metastasis stage, as well as SUVmax, MTV, TLG and HF parameters of primary tumours and LNs, were documented.

RESULTS

The analysis comprised 319 patients and 963 LNs. Patients had a mean age of 61.62 years, with 91.5% being male. Adenocarcinoma exhibited a histological association with LN metastasis (P=0.043). The study findings revealed that tumour size, SUVmax, MTV, TLG and HF did not significantly affect the detection of LN metastasis. Conversely, non-squamous cell carcinoma, LNs exhibiting higher FDG levels than the liver, LN size, SUVmax, MTV and TLG were identified as risk factors (P<0.0001). The identified cut-off values were 1.05cm for LN size, 4.055 for SUVmax, 1.805cm3 for MTV and 5.485 for TLG. The scoring system incorporated these parameters, and visual assessment indicated that a score of ≥3 increased the risk of metastasis by 14.33 times.

CONCLUSION

We devised a novel scoring system and demonstrated that LNs with a score of ≥3 in patients with NSCLC have a high likelihood of metastasis. This innovative scoring system can serve as a valuable tool to mitigate excessive and extreme measures in the assessment of invasive pathological staging.

Multicentric development and evaluation of [18F]FDG PET/CT and CT radiomic models to predict regional and/or distant recurrence in early-stage non-small cell lung cancer treated by stereotactic body radiation therapy

PURPOSE

To develop machine learning models to predict regional and/or distant recurrence in patients with early-stage non-small cell lung cancer (ES-NSCLC) after stereotactic body radiation therapy (SBRT) using [18F]FDG PET/CT and CT radiomics combined with clinical and dosimetric parameters.

METHODS

We retrospectively collected 464 patients (60% for training and 40% for testing) from University Hospital of Liège and 63 patients from University Hospital of Brest (external testing set) with ES-NSCLC treated with SBRT between 2010 and 2020 and who had undergone pretreatment [18F]FDG PET/CT and planning CT. Radiomic features were extracted using the PyRadiomics toolbox®. The ComBat harmonization method was applied to reduce the batch effect between centers. Clinical, radiomic, and combined models were trained and tested using a neural network approach to predict regional and/or distant recurrence.

RESULTS

In the training (n = 273) and testing sets (n = 191 and n = 63), the clinical model achieved moderate performances to predict regional and/or distant recurrence with C-statistics from 0.53 to 0.59 (95% CI, 0.41, 0.67). The radiomic (original_firstorder_Entropy, original_gldm_LowGrayLevelEmphasis and original_glcm_DifferenceAverage) model achieved higher predictive ability in the training set and kept the same performance in the testing sets, with C-statistics from 0.70 to 0.78 (95% CI, 0.63, 0.88) while the combined model performs moderately well with C-statistics from 0.50 to 0.62 (95% CI, 0.37, 0.69).

CONCLUSION

Radiomic features extracted from pre-SBRT analog and digital [18F]FDG PET/CT outperform clinical parameters in the prediction of regional and/or distant recurrence and to discuss an adjuvant systemic treatment in ES-NSCLC. Prospective validation of our models should now be carried out.

Elevated splenic 18F-fluorodeoxyglucose positron emission tomography/computed tomography activity is associated with 5-year risk of recurrence in non-metastatic invasive ductal carcinoma of the breast

OBJECTIVE

To construct prediction models including baseline 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) metabolic parameters of tumoural lesions and non-tumour lymphoid tissue for recurrence-free survival within 5 years (5y-RFS) after imaging examination in patients with invasive ductal carcinomas (IDCs) of the breast.

METHODS

The study included 101 consecutive female patients. Univariable and multivariable Cox regression were used to identify clinicopathological and metabolic parameters associated with risk of recurrence. Four prediction models based on the results of multivariable analysis were constructed and visualized as nomograms. Performance of each nomogram was evaluated using the concordance index (C-index), integrated discrimination improvement, decision curve analysis (DCA), and calibration curve.

RESULTS

N3 status, total metabolic tumour volume, the maximum standardized uptake value of spleen, and spleen-to-liver ratio were significant predictors of 5y-RFS. The nomogram including all significant predictors demonstrated superior predictive performance for 5y-RFS, with a C-index of 0.907 (95% CI, 0.833-0.981), greatest net benefit on DCA, good accuracy on calibration curves, and excellent risk stratification on Kaplan-Meier curves.

CONCLUSIONS

The model that included metabolic parameters of the spleen had the best performance for predicting 5y-RFS in patients with IDCs of the breast. This model may guide personalized treatment decisions and inform patients and clinicians about prognosis.

ADVANCES IN KNOWLEDGE

This research identifies 18F-FDG PET/CT metabolic parameters of non-tumour lymphoid tissue as predictors of recurrence in breast cancer.

Pretreatment and Posttreatment Tumor Metabolic Activity Assessed by FDG-PET/CT as Predictors of Tumor Recurrence and Survival Outcomes in Early-Stage Non-Small Cell Lung Cancer Treated With Stereotactic Body Radiation Therapy

Purpose

Stereotactic body radiation therapy (SBRT) is considered the standard of care for medically inoperable early-stage non-small cell lung cancer. There is mixed evidence on the prognostic significance of tumor metabolic activity assessed by positron emission tomography combined with computed tomography (PET/CT) using F-18 fluorodeoxyglucose (FDG). The objectives of this study were to evaluate the maximum standardized uptake value (SUVmax) pretreatment and at 3 and 6 months after SBRT for prediction of tumor control and survival outcomes.

Methods and Materials

Consecutive patients from a single institution with T12N0M0 non-small cell lung cancer receiving primary treatment with SBRT with pretreatment FDG-PET/CT (n = 163) and follow-up FDG-PET/CT at 3 or 6 months (n = 71) were included. Receiver operator characteristic analysis was performed to dichotomize variables for Kaplan-Meier survival analysis. Multivariate analysis was performed with Cox proportional hazards regression.

Results

Median follow-up was 19 months. For the whole cohort, 1-year and 2-year local control, progression-free survival (PFS), and overall survival (OS) were 95.0% and 80.3%, 87.1% and 75.4%, and 67.0% and 49.6% respectively. The following pre-SBRT SUVmax cutoffs were significant: SUV > 4.0 for distant failure-free survival (adjusted hazard ratio [aHR], 3.33, P = .006), >12.3 for PFS (aHR, 2.80, P = .011), and >12.6 for OS (aHR, 3.00, P = .003). SUVmax decreases of at least 45% at 3 months (aHR, 0.15, P = .018), and 53% at 6 months (aHR, 0.12, P = .046) were associated with improved local failure-free survival.

Conclusions

Pre-SBRT SUVmax cutoffs can predict distant failure, PFS, and OS. At both 3 and 6 months after SBRT, cutoffs for percentage change in SUVmax can potentially stratify risk of local recurrence.

Biomarkers in Cancer Detection, Diagnosis, and Prognosis

Biomarkers are vital in healthcare as they provide valuable insights into disease diagnosis, prognosis, treatment response, and personalized medicine. They serve as objective indicators, enabling early detection and intervention, leading to improved patient outcomes and reduced costs. Biomarkers also guide treatment decisions by predicting disease outcomes and facilitating individualized treatment plans. They play a role in monitoring disease progression, adjusting treatments, and detecting early signs of recurrence. Furthermore, biomarkers enhance drug development and clinical trials by identifying suitable patients and accelerating the approval process. In this review paper, we described a variety of biomarkers applicable for cancer detection and diagnosis, such as imaging-based diagnosis (CT, SPECT, MRI, and PET), blood-based biomarkers (proteins, genes, mRNA, and peptides), cell imaging-based diagnosis (needle biopsy and CTC), tissue imaging-based diagnosis (IHC), and genetic-based biomarkers (RNAseq, scRNAseq, and spatial transcriptomics).

The dual role of citrate in cancer

Citrate is a key metabolite of the Krebs cycle that can also be exported in the cytosol, where it performs several functions. In normal cells, citrate sustains protein acetylation, lipid synthesis, gluconeogenesis, insulin secretion, bone tissues formation, spermatozoid mobility, and immune response. Dysregulation of citrate metabolism is implicated in several pathologies, including cancer. Here we discuss how cancer cells use citrate to sustain their proliferation, survival, and metastatic progression. Also, we propose two paradoxically opposite strategies to reduce tumour growth by targeting citrate metabolism in preclinical models. In the first strategy, we propose to administer in the tumor microenvironment a high amount of citrate, which can then act as a glycolysis inhibitor and apoptosis inducer, whereas the other strategy targets citrate transporters to starve cancer cells from citrate. These strategies, effective in several preclinical in vitro and in vivo cancer models, could be exploited in clinics, particularly to increase sensibility to current anti-cancer agents.

Tumor to liver maximum standardized uptake value ratio of FDG-PET/CT parameters predicts tumor treatment response and survival of stage III non-small cell lung cancer

BACKGROUND

To assess the predictive values of primary tumor FDG uptake for patients with inoperable stage III non-small cell lung cancer (NSCLC) after concurrent chemoradiotherapy (CCRT).

METHODS

A total of 107 patients with diagnosis of stage III NSCLC and CCRT were enrolled. The tumor maximum uptake value (SUVmax) was standardized by calculating several ratios between tumor and each background tissues. The receiver operating characteristics curve (ROC) was used to compare the predictive power of prognostic models. The tumor objective response rate (ORR) and overall survival (OS) were compared and analyzed by the Kaplan-Meier method and univariate and multivariate Cox regression models.

RESULTS

The areas under ROC curve (AUCs) ranged from 0.72 to 0.81 among these tumor SUVmax and standardized SUVmax ratios, and the tumor SUVmax and tumor SUVmax-to-liver SUVmean ratio (TLMR) were more predictive of ORR (AUC, 0.81; 95% CI, 0.73-0.88 for tumor SUVmax and AUC, 0.84; 95%CI, 0.76-0.91 for TLMR) than any of other SUVmax ratios. The patients with lower tumor SUVmax, SUVmean and SUVmax ratios had a significantly better OS than those with their corresponding higher ones. Moreover, both univariate and multivariable analyses revealed that TLMR was significantly associated with better ORR and OS after adjustment with other prognostic variables.

CONCLUSIONS

TLMR, a standardized tumor SUVmax, was an independent prognostic predictor for tumor ORR and OS of patients with stage III NSCLC after CCRT.

Comprehensive analysis of suppressor of cytokine signaling 2 protein in the malignant transformation of NSCLC

Suppressor of cytokine signaling 2 (SOCS2) plays an essential role in a number of physiological phenomena and functions as a tumor suppressor. Understanding the predictive effects of SOCS2 on non-small cell lung cancer (NSCLC) is urgently needed. The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases were used to assess SOCS2 gene expression levels in NSCLC. The clinical significance of SOCS2 was evaluated through Kaplan-Meier curve analysis and the analysis of related clinical factors. Gene Set Enrichment Analysis (GSEA) was used to identify the biological functions of SOCS2. Subsequently proliferation, wound-healing, colony formation and Transwell assays, and carboplatin drug experiments were used for verification. The results revealed that SOCS2 expression was low in the NSCLC tissues of patients in TCGA and GEO database analyses. Downregulated SOCS2 was associated with poor prognosis, as determined by Kaplan-Meier survival analysis (HR 0.61, 95% CI 0.52-0.73; P<0.001). GSEA showed that SOCS2 was involved in intracellular reactions, including epithelial-mesenchymal transition (EMT). Cell experiments indicated that knockdown of SOCS2 caused the malignant progression of NSCLC cell lines. Furthermore, the drug experiment showed that silencing of SOCS2 promoted the resistance of NSCLC cells to carboplatin. In conclusion, low expression of SOCS2 was associated with poor clinical prognosis by effecting EMT and causing drug resistance in NSCLC cell lines. Furthermore, SOCS2 could act as a predictive indicator for NSCLC.

Pretreatment 18-FDG-PET/CT parameters can serve as prognostic imaging biomarkers in recurrent NSCLC patients treated with reirradiation-chemoimmunotherapy

BACKGROUND AND PURPOSE

Our study aimed to assess whether quantitative pretreatment 18F-FDG-PET/CT parameters could predict prognostic clinical outcome of recurrent NSCLC patients who may benefit from ablative reirradiation.

MATERIALS AND METHODS

Forty-eight patients with recurrent NSCLC of all UICC stages who underwent ablative thoracic reirradiation were analyzed. Twenty-nine (60%) patients received immunotherapy with or without chemotherapy in addition to reirradiation. Twelve patients (25%) received reirradiation only and seven (15%) received chemotherapy and reirradiation. Pretreatment 18-FDG-PET/CT was mandatory in initial diagnosis and recurrence, based on which volumetric and intensity quantitative parameters were measured before reirradiation and their impact on overall survival, progression-free survival, and locoregional control was assessed.

RESULTS

With a median follow-up time of 16.7 months, the median OS was 21.8 months (95%-CI: 16.2-27.3). On multivariate analysis, OS and PFS were significantly influenced by MTV (p < 0.001 for OS; p = 0.006 for PFS), TLG (p < 0.001 for OS; p = 0.001 for PFS) and SUL peak (p = 0.0024 for OS; p = 0.02 for PFS) of the tumor and MTV (p = 0.004 for OS; p < 0.001 for PFS) as well as TLG (p = 0.007 for OS; p = 0.015 for PFS) of the metastatic lymph nodes. SUL peak of the tumor (p = 0.05) and the MTV of the lymph nodes (p = 0.003) were only PET quantitative parameters that significantly impacted LRC.

CONCLUSION

Pretreatment tumor and metastastic lymph node MTV, TLG and tumor SUL peak significantly correlated with clinical outcome in recurrent NSCLC patients treated with reirradiation-chemoimmunotherapy.

Combination of Circulating Cell-Free DNA and Positron Emission Tomography to Distinguish Non-Small Cell Lung Cancer from Tuberculosis

OBJECTIVE

Non-small cell lung cancer (NSCLC) holds high metabolic tumor burden and circulating cell-free DNA (cfDNA) levels, and the relationship between metabolic tumor burden and cfDNA in NSCLC and the underlying mechanism of their interaction therein remain poorly characterized. Our aim was to evaluate the clinical value of cfDNA and metabolic tumor burden by positron emission tomography-computed tomography (PET/CT) for NSCLC differential diagnosis from tuberculosis in patients with solitary pulmonary nodules.

METHODS

Metabolic tumor burden values in humans (subjects with NSCLC, subjects with tuberculosis, and healthy control subjects) and relevant mouse models were detected by preoperative 18F-fluorodeoxyglucose PET (18F-FDG PET/CT) and [3H]-2-deoxy-DG uptake, respectively. The cfDNA levels were detected by quantifying serum cfDNA fragments from the ALU (115 bp) gene using reverse transcription-polymerase chain reaction. RNA sequence was performed to determine the underlying target genes and knocked down or inhibited the target genes in vivo and in vitro to determine the mechanism therein.

RESULTS

Metabolic tumor burden correlated with serum cfDNA levels in NSCLC subjects but not in tuberculosis subjects or healthy controls. Mouse models showed a similar phenomenon. In addition, the RNA sequence showed that glucose transporter 1 (GLU1), factor-related apoptosis ligand (FasL), caspase 8, and caspase 3 were significantly increased in NSCLC mouse tumors compared with those in tuberculosis mouse masses. Inhibiting the metabolic tumor burden by blocking or knocking down GLU1 markedly reduced the expression of FasL, the phosphorylation of caspase 8/caspase 3, and serum cfDNA levels/apoptosis percentage in vivo and in vitro. Furthermore, the use of a combination of cfDNA and metabolic tumor burden allowed better ability to distinguish NSCLC subjects from those with tuberculosis or healthy controls than either method used alone.

CONCLUSION

Metabolic tumor burden promotes the formation of circulating cfDNA through GLU1-mediated apoptosis in NSCLC, and the combination of cfDNA and metabolic tumor burden could be valuable for distinguishing NSCLC from tuberculosis.

Salvage surgery in lung cancer following definitive therapies

Salvage surgery refers to operative resection of persistent or recurrent disease in patients initially treated with intention-to-cure nonoperative management. In non-small-cell lung cancer, salvage surgery may be effective in treating selected patients with locally progressive tumors, recurrent local or locoregional disease, or local complications after nonoperative therapy. Importantly, those patients who may be candidates for salvage surgery are evolving, in terms of disease stage as well as the types of attempted definitive therapy received.

[Advances in the Study of Invasive Non-mucinous Adenocarcinoma with Different Pathological Subtypes]

Lung cancer is the leading cause of cancer death in the world today, and adenocarcinoma is the most common histopathological type of lung cancer. In May 2021, World Health Organization (WHO) released the 5th edition of the WHO classification of thoracic tumors, which classifies invasive non-mucinous adenocarcinoma (INMA) into lepidic adenocarcinoma, acinar adenocarcinoma, papillary adenocarcinoma, solid adenocarcinoma, and micropapillary adenocarcinoma based on its histological characteristics. These five pathological subtypes differ in clinical features, treatment and prognosis. A complete understanding of the characteristics of these subtypes is essential for the clinical diagnosis, treatment options, and prognosis predictions of patients with lung adenocarcinoma, including recurrence and progression. This article will review the grading system, morphology, imaging prediction, lymph node metastasis, surgery, chemotherapy, targeted therapy and immunotherapy of different pathological subtypes of INMA.
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Predictive Value of Baseline FDG-PET/CT for the Durable Response to Immune Checkpoint Inhibition in NSCLC Patients Using the Morphological and Metabolic Features of Primary Tumors

Objectives: We aimed to investigate the predictive value of baseline 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) for durable responses to immune checkpoint inhibitors (ICIs) by linking the morphological and metabolic features of primary tumors (PTs) in nonsmall cell lung cancer (NSCLC) patients. Methods: For the purpose of this single-center study, the imaging data of the patients with a first diagnosis of NSCLC and an available baseline FDG-PET/CT between 2020 and 2021 were retrospectively assessed. The baseline characteristics were collected based on clinical reports and interdisciplinary tumor board documentation. The metabolic (such as standardized uptake value SUV maximum and mean (SUVmax, SUV mean), metabolic tumor volume (MTV), total lesion glycolysis (TLG)) and morphological (such as volume, morphology, margin, and presence of lymphangiosis through imaging) features of all the PTs were retrospectively assessed using FDG-PET/CT. Overall survival (OS), progression-free survival (PFS), clinical benefit (CB) and mortality rate were used as endpoints to define the long-term response to therapy. A backward, stepwise logistic regression analysis was performed in order to define the best model for predicting lasting responses to treatment. Statistical significance was assumed at p < 0.05. Results: A total of 125 patients (median age ± standard deviation (SD) 72.0 ± 9.5 years) were enrolled: 64 men (51.2%) and 61 women (48.8%). Adenocarcinoma was by far the most common histological subtype of NSCLC (47.2%). At the initial diagnosis, the vast majority of all the included patients showed either locally advanced disease (34.4%) or metastatic disease (36.8%). Fifty patients were treated with ICIs either as a first-line (20%) or second-line (20%) therapy, while 75 patients did not receive ICIs. The median values ± SD of PT SUVmax, mean, MTV, and TLG were respectively 10.1 ± 6.0, 6.1 ± 3.5, 13.5 ± 30.7, and 71.4 ± 247.7. The median volume of PT ± SD was 13.7 ± 30.7 cm3. The PTs were most frequently solid (86.4%) with irregular margins (76.8%). Furthermore, in one out of five cases, the morphological evidence of lymphangiosis was seen through imaging (n = 25). The median follow-up ± SD was 18.93 ± 6.98 months. The median values ± SD of OS and PFS were, respectively, 14.80 ± 8.68 months and 14.03 ± 9.02 months. Age, PT volume, SUVmax, TLG, the presence of lymphangiosis features through imaging, and clinical stage IV were very strong long-term outcome predictors of patients treated with ICIs, while no significant outcome predictors could be found for the cohort with no ICI treatment. The optimal cut-off values were determined for PT volume (26.94 cm3) and SUVmax (15.05). Finally, 58% of NSCLC patients treated with ICIs had a CB vs. 78.7% of patients in the cohort with no ICI treatment. However, almost all patients treated with ICIs and with disease progression over time died (mortality in the case of disease progression 95% vs. 62.5% in the cohort without ICIs). Conclusion: Baseline FDG-PET/CT could be used to predict a durable response to ICIs in NSCLC patients. Age, clinical stage IV, lymphangiosis features through imaging, PT volume (thus PT MTV due to a previously demonstrated linear correlation), PT SUVmax, and TLG were very strong long-term outcome predictors. Our results highlight the importance of linking clinical data, as much as morphological features, to the metabolic parameters of primary tumors in a multivariate outcome-predicting model using baseline FDG-PET/CT.

Comparison of Conventional Imaging and 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Diagnostic Accuracy of Staging in Patients with Intrahepatic Cholangiocarcinoma

We aimed to examine the accuracy of tumor staging of intrahepatic cholangiocarcinoma (ICC) by using 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET-CT). From January 2001 to December 2021, 202 patients underwent PET-CT, CT, and MRI for the initial staging of ICC in two institutions. Among them, 102 patients had undergone surgical treatment. Ninety patients who had a histopathological diagnosis of ICC were retrospectively reviewed. The sensitivity and specificity of 18F-FDG PET-CT, CT, and magnetic resonance imaging (MRI) in detecting tumors, satellite focus, vascular invasion, and lymph node metastases were analyzed. Ninety patients with histologically diagnosed ICC were included. PET-CT demonstrated no statistically significant advantage over CT and MR in the diagnosis of multiple tumors and macrovascular invasion, and bile duct invasion. The overall sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of PET-CT in lymph node metastases were 84%, 86%, 91%, 84%, and 86%, respectively. PET-CT revealed a significantly higher accuracy compared to CT or MRI (86%, 67%, and 76%, p < 0.01, respectively) in the diagnosis of regional lymph node metastases. The accuracy of tumor staging by PET-CT was higher than that by CT/MRI (PET-CT vs. CT vs. MRI: 68/90 vs. 47/90 vs. 51/90, p < 0.05). 18F-FDG PET-CT had sensitivity and specificity values for diagnosing satellite focus and vascular and bile duct invasion similar to those of CT or MRI; however, PET-CT showed higher accuracy in diagnosing regional lymph node metastases. 18F-FDG PET-CT exhibited higher tumor staging accuracy than that of CT/MRI. Thus, 18FDG PET-CT may support tumor staging in ICC.

18F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography Interpretation Criteria for the Assessment of Therapeutic Response in Patients with Advanced Stage of Lung Cancer: Inter-Reader Reliability, Accuracy, and Survival Outcomes

Aim

18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG-PET/CT) is useful in the evaluation of lung cancer (LC), both for staging and therapy assessment. However, for the evaluation of treatment response, shared criteria are not available. We proposed a 3-point score, similar to Deauville-score and compared its diagnostic accuracy with Hopkins criteria for the evaluation of treatment response in LC to validate a qualitative and simpler interpretation system.

Methods

We retrospectively included 93 patients with advanced stage (III-IV) LC who underwent 18F-FDG-PET/CT after first-line treatment. Positron emission tomography/computed tomography (PET/CT) scans were interpreted according to a 3-point scale-like Deauville score criteria (score 1 = uptake lower than blood-pool activity; score 2 = uptake higher than blood-pool but lower than liver activity; score 3 = uptake higher than liver). Inter-reader variability was assessed using percent agreement and kappa statistics. Kaplan-Meier plots with a Mantel-Cox log-rank test were performed, considering death as the endpoint.

Results

The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of like Deauville-like score criteria were 82,76% (95% confidence interval [CI] 70.5%-91.4%), 80% (95% CI 28.3%-99%), 97.9% (95% CI 89.2%-99.6%), 28.6%(95% CI 16.38%-44.9%), and 82.5% (95% CI 70.9-90.9%), respectively. Applying Hopkins criteria score we obtained sensitivity, specificity, PPV, NPV, and accuracy of 81% [95% CI 68.6%-90.1%), 100% (95% CI 47.2-100%), 100% (95% CI %), 31.3% (95% CI 21.0%-43%), and 82.5%(95% CI 70.9%-90.9%), respectively. There was a high agreement between the two readers both using Hopkins criteria (k = 0.912) and like-Deauville-score criteria (k = 0.956). Applying 3-point-scale criteria, patients with positive PET/CT after therapy had significantly shorter lower survival (P = 0.0021).

Conclusion

The application of 3-point scale criteria for posttherapy assessment in patients with advanced stage of LC represents an easy and reproducible method with optimal inter-observer agreement and great PPV and accuracy.

State of the Art: Lung Cancer Staging Using Updated Imaging Modalities

Lung cancer is among the most common mortality causes worldwide. This scientific article is a comprehensive review of current knowledge regarding screening, subtyping, imaging, staging, and management of treatment response for lung cancer. The traditional imaging modality for screening and initial lung cancer diagnosis is computed tomography (CT). Recently, a dual-energy CT was proven to enhance the categorization of variable pulmonary lesions. The National Comprehensive Cancer Network (NCCN) recommends usage of fluorodeoxyglucose positron emission tomography (FDG PET) in concert with CT to properly stage lung cancer and to prevent fruitless thoracotomies. Diffusion MR is an alternative to FDG PET/CT that is radiation-free and has a comparable diagnostic performance. For response evaluation after treatment, FDG PET/CT is a potent modality which predicts survival better than CT. Updated knowledge of lung cancer genomic abnormalities and treatment regimens helps to improve the radiologists’ skills. Incorporating the radiologic experience is crucial for precise diagnosis, therapy planning, and surveillance of lung cancer.

Prediction of lung malignancy progression and survival with machine learning based on pre-treatment FDG-PET/CT

Background

Pre-treatment FDG-PET/CT scans were analyzed with machine learning to predict progression of lung malignancies and overall survival (OS).

Methods

A retrospective review across three institutions identified patients with a pre-procedure FDG-PET/CT and an associated malignancy diagnosis. Lesions were manually and automatically segmented, and convolutional neural networks (CNNs) were trained using FDG-PET/CT inputs to predict malignancy progression. Performance was evaluated using area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, and specificity. Image features were extracted from CNNs and by radiomics feature extraction, and random survival forests (RSF) were constructed to predict OS. Concordance index (C-index) and integrated brier score (IBS) were used to evaluate OS prediction.

Findings

1168 nodules (n=965 patients) were identified. 792 nodules had progression and 376 were progression-free. The most common malignancies were adenocarcinoma (n=740) and squamous cell carcinoma (n=179). For progression risk, the PET+CT ensemble model with manual segmentation (accuracy=0.790, AUC=0.876) performed similarly to the CT only (accuracy=0.723, AUC=0.888) and better compared to the PET only (accuracy=0.664, AUC=0.669) models. For OS prediction with deep learning features, the PET+CT+clinical RSF ensemble model (C-index=0.737) performed similarly to the CT only (C-index=0.730) and better than the PET only (C-index=0.595), and clinical only (C-index=0.595) models. RSF models constructed with radiomics features had comparable performance to those with CNN features.

Interpretation

CNNs trained using pre-treatment FDG-PET/CT and extracted performed well in predicting lung malignancy progression and OS. OS prediction performance with CNN features was comparable to a radiomics approach. The prognostic models could inform treatment options and improve patient care.

Funding

NIH NHLBI training grant (5T35HL094308-12, John Sollee).

Applying PET-CT for predicting the efficacy of SBRT to inoperable early-stage lung adenocarcinoma: A Brazilian case-series

BACKGROUND

Stereotactic body radiotherapy (SBRT) is a treatment option for early-stage inoperable primary lung cancer. Here we report a thorough description of the prognostic value of pre-SBRT SUVmax for predicting the efficacy of SBRT in early-stage lung adenocarcinoma.

METHODS

This is a retrospective study of consecutive cases of early-stage inoperable lung adenocarcinoma, staged with PET-CT, treated with SBRT between 2007 and 17. Kaplan-Meier (KM) curves were used to assess overall survival and compare time to event between those with PET-CT SUVmax values ≤ 5.0 and those > 5. Fisher's Exact tests and the Mann-Whitney U were used to compare the patient and clinical data of those with SUVmax≤5.0 and >5.0, and those with and without any failure.

FINDINGS

Amongst 50 lung carcinoma lesions, from 47 patients (34 (68%)-T1a or <T1b), estimated median overall survival from the KM was 44.9 months (95% confidence interval 35.5-54.3). Five experienced a local failure, which was inadequate for detecting differences between those with PET-CT SUVmax ≤5.0 and those >5 (p = 0.112). In addition, 5 experienced a regional failure and 4 a distant failure. Higher PET-CT SUVmax values before SBRT were associated with an increased risk of any failure (36% versus 0%, p = 0.0040 on Fisher's Exact test) and faster time to event (p = 0.010, log rank test). Both acute and late toxicities profile were acceptable.

INTERPRETATION

Patients with early-stage inoperable lung adenocarcinoma present good clinical outcomes when treated with SBRT. We raised the hypothesis that the value of PET-CT SUVmax before SBRT may be an important predictive factor in disease control.

FUNDING

None.

The prognostic value of 18F-FDG PET/CT taken immediately after completion of radiotherapy for lung cancer treated with concurrent chemoradiotherapy: A pilot study

PURPOSE

The prognostic value of F-18 fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) taken immediately after completion of radiotherapy in lung cancer patients is not well known. The purpose of this study is to assess the prognostic value of PET/CT taken immediately after completion of radiotherapy in lung cancer patients.

MATERIALS AND METHODS

Patients with primary lung cancer planned to undergo concurrent chemoradiotherapy were enrolled. Patients underwent PET/CT scans at 3 time points: before radiotherapy, within 24hours of completing radiotherapy (im-PET/CT), and 2-9 months after radiotherapy (post-PET/CT). Maximum standardized uptake value (SUV_max) was obtained. A post-PET/CT-SUV_max cut-off of 2.5 was determined as radiotherapy success.

RESULTS

Nineteen patients were enrolled. im-PET/CT-SUV_max for patients in the high post-PET/CT-SUV_max group was significantly higher than that of the low group (P=0.004). Receiver operator curve analysis indicated that im-PET/CT-SUV_max of 4.35 was an optimal cut-off value to discriminate between the two groups. Multivariable analysis showed that a high im-PET/CT-SUV_max was significantly associated with a high post-PET/CT-SUV_max (P=0.003).

CONCLUSION

PET/CT-SUV_max taken immediately following radiotherapy was associated with that evaluated 2-9 months after radiotherapy.

Evaluation of response to stereotactic body radiation therapy for nonsmall cell lung cancer: PET response criteria in solid tumors versus response evaluation criteria in solid tumors

OBJECTIVE

Recommendations for surveillance after stereotactic body radiation therapy (SBRT) for early-stage nonsmall cell lung cancer (NSCLC) are not well defined. Recently, PET response criteria in solid tumors (PERCIST) have been proposed as a new standardized method to assess radiotherapeutic response both quantitatively and metabolically. The aim of this study was to evaluate therapeutic response following SBRT in early-stage NSCLC patients by comparing PERCIST with the currently widely used RECIST.

MATERIALS AND METHODS

Forty-nine patients with early-stage NSCLC who had been prescribed SBRT were studied. Responses of lesion were evaluated using CT and 18F-FDG PET according to the RECIST and PERCIST methods. PET-CT scans were obtained before SBRT and 3-6 months after SBRT. Associations between overall survival (OS) and clinicopathologic results (histology, tumor location, tumor size, lymphatic invasion, clinical stage, and radiotherapeutic responses in RECIST and PERCIST) were statistically analyzed. The median patient follow-up was 30 months.

RESULTS

Thirteen patients had stage IA, 9 stage IB, 10 stage IIA, and 17 stage IIB biopsy-proven NSCLC. Three-year OS was 79.6%. CT scans indicated three regional recurrences. PET-CT/chest indicated three regional recurrences and distant metastasis. Significant differences were observed in response classification between RECIST and PERCIST (Wilcoxon signed-rank test, P = 0.0041). Univariate analysis showed that clinical stage, RECIST, and PERCIST were significant factors associated with OS, whereas by multivariate analysis PERCIST was the only predictor of OS. SMD, PMD/PMR, and CMR in PERCIST criteria were indicative of a 9.900-fold increase in the risk of OS in early NSCLC patients [risk ratio, 9.900 (95% CI, 1.040-21.591); P = 0.001].

CONCLUSION

RECIST based on the anatomic size reduction rate did not demonstrate the correlation between radiotherapeutic response and prognosis in patients with early-stage NSCLC receiving SBRT. However, PERCIST was shown as the strongest independent predictor of outcomes. PERCIST might be considered more suitable for the evaluation of NSCLC tumor response to SBRT than RECIST.

Effects of cigarette smoking on metabolic activity of lung cancer on baseline 18F-FDG PET/CT

Background

Never-smokers with lung cancer usually have a higher survival rate than that of smokers. The high metabolic activity of lung cancer on ¹⁸F-2-Fluoro-2-deoxyglucose (¹⁸F-FDG) PET/CT generally indicates a poor outcome. However, there is a lack of reports on the association between cigarette smoking and ¹⁸F-FDG metabolic activity in patients with lung cancer. In this study, we aimed to investigate the effects of cigarette smoking on metabolic activity of lung cancer on ¹⁸F-FDG PET/CT.

Materials and Methods

A total of 338 patients (230 males, 108 females; mean age: 66.3, range 34-86) with pathologically diagnosed lung cancer were enrolled from September 2019 to April 2021. All patients underwent baseline ¹⁸F-FDG PET/CT and the maximum standard uptake value (SUVmax) of the primary tumor (pSUVmax), lymph node (nSUVmax) and distant metastasis (mSUVmax) were measured. The associations between cigarette smoking status, clinical stage, pathological subtypes and metabolic parameters on ¹⁸F-FDG PET/CT were analyzed.

Results

Of the 338 patients, cigarette smoking was identified in 153 patients (45.3%) and the remaining 185 (54.7%) were never-smokers. Smoking was found more frequently in males, squamous cell carcinoma (SCC) and stage III-IV diseases. The pSUVmax in smokers was significantly higher than that in never-smokers (t = 3.386, P < 0.001), but the nSUVmax and mSUVmax revealed no statistically significant differences (t = 0.399, P = 0.690 and t = 0.057, P = 0.955; respectively). With the increase of cumulative smoking dose, pSUVmax increased significantly (r = 0.217, P < 0.001). In addition, the pSUVmax in patients with stage III-IV was significantly higher than that in stage I-II (t = 8.509, P < 0.001). Smokers showed a higher pSUVmax than never-smokers for patients with stage I-II (t = 3.106, P = 0.002), but not in stage III-IV (t = 0.493, P = 0.622). The pSUVmax was significantly different among patients with different pathological subtypes of lung cancer (F = 11.45, P < 0.001), while only the adenocarcinoma (ADC) and SCC groups showed a difference in pSUVmax (t = 6.667, P < 0.001). Smokers with ADC showed a higher pSUVmax when compared to never-smokers, but not in SCC. There were no significant differences of pSUVmax between smokers and never-smokers at stage I-II ADC or SCC and stage III-IV ADC or SCC.

Conclusions

This study demonstrated a close association between cigarette smoking and the metabolic activity of lung cancer and suggests that smoking may be a potential risk factor of higher pSUVmax in early lung cancer on ¹⁸F-FDG PET/CT.

Prognostic Value of Early Fluorodeoxyglucose-Positron Emission Tomography Response Imaging and Peripheral Immunologic Biomarkers: Substudy of a Phase II Trial of Risk-Adaptive Chemoradiation for Unresectable Non-Small Cell Lung Cancer

Purpose

We sought to examine the prognostic value of fluorodeoxyglucose-positron emission tomography (PET) imaging during chemoradiation for unresectable non-small cell lung cancer for survival and hypothesized that tumor PET response is correlated with peripheral T-cell function.

Methods and Materials

Forty-five patients with American Joint Committee on Cancer version 7 stage IIB-IIIB non-small cell lung cancer enrolled in a phase II trial and received platinum-doublet chemotherapy concurrent with 6 weeks of radiation (NCT02773238). Fluorodeoxyglucose-PET was performed before treatment start and after 24 Gy of radiation (week 3). PET response status was prospectively defined by multifactorial radiologic interpretation. PET responders received 60 Gy in 30 fractions, while nonresponders received concomitant boosts to 74 Gy in 30 fractions. Peripheral blood was drawn synchronously with PET imaging, from which germline DNA sequencing, T-cell receptor sequencing, and plasma cytokine analysis were performed.

Results

Median follow-up was 18.8 months, 1-year overall survival (OS) 82%, 1-year progression-free survival 53%, and 1-year locoregional control 88%. Higher midtreatment PET total lesion glycolysis was detrimental to OS (1 year 87% vs 63%, P < .001), progression-free survival (1 year 60% vs 26%, P = .044), and locoregional control (1 year 94% vs 65%, P = .012), even after adjustment for clinical/treatment factors. Twenty-nine of 45 patients (64%) were classified as PET responders based on a priori definition. Higher tumor programmed death-ligand 1 expression was correlated with response on PET (P = .017). Higher T-cell receptor richness and clone distribution slope were associated with improved OS (P = .018-0.035); clone distribution slope was correlated with PET response (P = .031).

Conclusions

Midchemoradiation PET imaging is prognostic for survival; PET response may be linked to tumor and peripheral T-cell biomarkers.

SUVmax to tumor perimeter distance: a robust radiomics prognostic biomarker in resectable non-small cell lung cancer patients

OBJECTIVE

The purpose of this study was to evaluate the prognostic value of novel geometric variables obtained from pre-treatment [¹⁸F]FDG PET/CT with respect to classical ones in patients with non-small cell lung cancer (NSCLC).

METHODS

Retrospective study including stage I-III NSCLC patients with baseline [¹⁸F]FDG PET/CT. Clinical, histopathologic, and metabolic parameters were obtained. After tumor segmentation, SUV and volume-based variables, global texture, sphericity, and two novel parameters, normalized SUVpeak to centroid distance (nSCD) and normalized SUVmax to perimeter distance (nSPD), were obtained. Early recurrence (ER) and short-term mortality (STM) were used as end points. Univariate logistic regression and multivariate logistic regression with respect to ER and STM were performed.

RESULTS

A cohort of 173 patients was selected. ER was detected in 49/104 of patients with recurrent disease. Additionally, 100 patients died and 53 had STM. Age, pathologic lymphovascular invasion, lymph nodal infiltration, TNM stage, nSCD, and nSPD were associated with ER, although only age (aOR = 1.06, p = 0.002), pathologic lymphovascular invasion (aOR = 3.40, p = 0.022), and nSPD (aOR = 0.02, p = 0.018) were significant independent predictors of ER in multivariate analysis. Age, lymph nodal infiltration, TNM stage, nSCD, and nSPD were predictors of STM. Age (aOR = 1.05, p = 0.006), lymph nodal infiltration (aOR = 2.72, p = 0.005), and nSPD (aOR = 0.03, p = 0.022) were significantly associated with STM in multivariate analysis. Coefficient of variation (COV) and SUVmean/SUVmax ratio did not show significant predictive value with respect to ER or STM.

CONCLUSION

The geometric variables, nSCD and nSPD, are robust biomarkers of the poorest outcome prediction of patients with NSCLC with respect to classical PET variables.

KEY POINTS

• In NSCLC patients, it is crucial to find prognostic parameters since TNM system alone cannot explain the variation in lung cancer survival. • Age, lymphovascular invasion, lymph nodal infiltration, and metabolic geometrical parameters were useful as prognostic parameters. • The displacement grade of the highest point of metabolic activity towards the periphery assessed by geometric variables obtained from [¹⁸F]FDG PET/CT was a robust biomarker of the poorest outcome prediction of patients with NSCLC.

Joint EANM/SNMMI/ESTRO practice recommendations for the use of 2-[18F]FDG PET/CT external beam radiation treatment planning in lung cancer V1.0

Purpose

2-[¹⁸F]FDG PET/CT is of utmost importance for radiation treatment (RT) planning and response monitoring in lung cancer patients, in both non-small and small cell lung cancer (NSCLC and SCLC). This topic has been addressed in guidelines composed by experts within the field of radiation oncology. However, up to present, there is no procedural guideline on this subject, with involvement of the nuclear medicine societies.

Methods

A literature review was performed, followed by a discussion between a multidisciplinary team of experts in the different fields involved in the RT planning of lung cancer, in order to guide clinical management. The project was led by experts of the two nuclear medicine societies (EANM and SNMMI) and radiation oncology (ESTRO).

Results and conclusion

This guideline results from a joint and dynamic collaboration between the relevant disciplines for this topic. It provides a worldwide, state of the art, and multidisciplinary guide to 2-[¹⁸F]FDG PET/CT RT planning in NSCLC and SCLC. These practical recommendations describe applicable updates for existing clinical practices, highlight potential flaws, and provide solutions to overcome these as well. Finally, the recent developments considered for future application are also reviewed.

Perspective paper about the joint EANM/SNMMI/ESTRO practice recommendations for the use of 2-[18F]FDG-PET/CT external beam radiation treatment planning in lung cancer

In “Joint EANM/SNMMI/ESTRO Practice Recommendations for the Use of 2-[18F]FDG-PET/CT External Beam Radiation Treatment Planning in Lung Cancer V1.0” clinical indications for PET-CT in (non-)small cell lung cancer are highlighted and selective nodal irradiation is discussed. Additionally, concepts about target definition, target delineation and treatment evaluation are reviewed.

Prognostic Value of FDG PET/CT in Patients With Neuroendocrine Carcinoma of the Uterine Cervix

PURPOSE

We evaluated the prognostic value of metabolic parameters measured on pretreatment FDG PET/CT in patients with cervical neuroendocrine carcinomas (NECs).

METHODS

A total of 22 patients with cervical NECs who underwent pretreatment FDG PET/CT were retrospectively reviewed. The SUVmax, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of the primary lesion were measured. The associations between prognostic factors and progression-free survival (PFS) and overall survival (OS) were investigated using the Kaplan-Meier method, log-rank test, and univariate and multivariate Cox proportional hazards model.

RESULTS

Of the 22 patients, 12 developed disease progression, and 5 died during the follow-up period. Univariate analyses revealed that MTV, TLG, and the International Federation of Gynecology and Obstetrics stage were significantly associated with PFS (all P < 0.05), whereas SUVmax did not show a significant correlation with PFS. Kaplan-Meier survival curves revealed that patients with MTV >31.9 cm3 (log-rank, P < 0.001), TLG >154.3 (log-rank, P < 0.001), and higher International Federation of Gynecology and Obstetrics stage (log-rank, P = 0.026) had significantly shorter PFS. In the multivariate analyses, MTV (P = 0.017; hazard ratio [HR], 7.298; 95% confidence interval [CI], 1.427-37.316) and TLG (P = 0.003; HR, 15.175; 95% CI, 2.470-93.244) were independent prognostic factors, whereas for OS, the univariate analysis revealed that only TLG >154.3 showed statistical significance (P = 0.043; HR, 9.821; 95% CI, 1.080-89.290).

CONCLUSIONS

Metabolic tumor volume and TLG on FDG PET/CT were the significant prognostic factors of PFS in patients with cervical NECs. Patients with high MTV and TLG had worse clinical outcomes. In addition, TLG may also be a predictor of OS.

Reliability of Quantitative 18F-FDG PET/CT Imaging Biomarkers for Classifying Early Response to Chemoradiotherapy in Patients With Locally Advanced Non-Small Cell Lung Cancer

PURPOSE OF THE REPORT

We evaluated the reliability of 18F-FDG PET imaging biomarkers to classify early response status across observers, scanners, and reconstruction algorithms in support of biologically adaptive radiation therapy for locally advanced non-small cell lung cancer.

PATIENTS AND METHODS

Thirty-one patients with unresectable locally advanced non-small cell lung cancer were prospectively enrolled on a phase 2 trial (NCT02773238) and underwent 18F-FDG PET on GE Discovery STE (DSTE) or GE Discovery MI (DMI) PET/CT systems at baseline and during the third week external beam radiation therapy regimens. All PET scans were reconstructed using OSEM; GE-DMI scans were also reconstructed with BSREM-TOF (block sequential regularized expectation maximization reconstruction algorithm incorporating time of flight). Primary tumors were contoured by 3 observers using semiautomatic gradient-based segmentation. SUVmax, SUVmean, SUVpeak, MTV (metabolic tumor volume), and total lesion glycolysis were correlated with midtherapy multidisciplinary clinical response assessment. Dice similarity of contours and response classification areas under the curve were evaluated across observers, scanners, and reconstruction algorithms. LASSO logistic regression models were trained on DSTE PET patient data and independently tested on DMI PET patient data.

RESULTS

Interobserver variability of PET contours was low for both OSEM and BSREM-TOF reconstructions; intraobserver variability between reconstructions was slightly higher. ΔSUVpeak was the most robust response predictor across observers and image reconstructions. LASSO models consistently selected ΔSUVpeak and ΔMTV as response predictors. Response classification models achieved high cross-validated performance on the DSTE cohort and more variable testing performance on the DMI cohort.

CONCLUSIONS

The variability FDG PET lesion contours and imaging biomarkers was relatively low across observers, scanners, and reconstructions. Objective midtreatment PET response assessment may lead to improved precision of biologically adaptive radiation therapy.

Prognostication Based on Texture Analysis of Baseline 18F Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Nonsmall-Cell Lung Carcinoma Patients Who Underwent Platinum-Based Chemotherapy as First-Line Treatment

Objective:

Our study aims to establish the potential for tumor heterogeneity evaluated using ¹⁸F fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) texture analysis in nonsmall-cell lung carcinoma (NSCLC) patients who underwent platinum-based chemotherapy to provide an independent marker for overall survival (OS) of more than 1-year.

Materials and Methods:

A total of 42 patients (34 male and 8 female) with biopsy-proven NSCLC and mean age 55.33 ± 10.71 years who underwent a baseline F-18 FDG PET/CT and received platinum-based chemotherapy as first-line treatment were retrospectively included in the study. Ten first order, 21 s order texture parameters and 7 SUV and metabolic tumor volume (MTV) based metabolic parameters were calculated. All these parameters were compared between the two survival groups based on OS ≥1 year and OS <1 year. Cut-offs of significant parameters were determined using receiver operating characteristic curve analysis. Survival patterns were compared by log-rank test and presented using Kaplan-Meier curves. Cox proportion hazard model was used to determine the independent prognostic marker for 1 year OS.

Results:

In univariate survival analysis, 3 first order texture parameters (i.e. mean, median, root mean square with hazard ratios [HRs] 2.509 [P = 0.034], 2.590 [P = 0.05], 2.509 [P = 0.034], respectively) and 6 s order texture parameters (i.e. mean, auto correlation, cluster prominence, cluster shade, sum average and sum variance with HRs 2.509 [P = 0.034], 2.509 [P = 0.034], 3.929 [0.007], 2.903 [0.018], 2.954 [0.016] and 2.906 [0.014], respectively) were significantly associated with 1 year OS in these patients. Among the metabolic parameters, only metabolic tumor volume whole-body was significantly associated with 1 year OS. In multivariate survival analysis, cluster prominence came out as the independent predictor of 1 year OS.

Conclusion:

Texture analysis based on F-18 FDG PET/CT is potentially beneficial in the prediction of OS ≥1 year in NSCLC patients undergoing platinum-based chemotherapy as first-line treatment. Thus, can be used to stratify the patients which will not be benefitted with platinum-based chemotherapy and essentially needs to undergo some other therapy option.

The ratio between the whole-body and primary tumor burden, measured on 18F-FDG PET/CT studies, as a prognostic indicator in advanced non-small cell lung cancer

Objective

To determine whether the whole-body tumor burden, as quantified by ¹⁸F-fluorodeoxyglucose positron-emission tomography/computed tomography (¹⁸F-FDG PET/CT), is a prognostic indicator in advanced (stage III or IV) non-small cell lung cancer (NSCLC).

Materials and Methods

This was a prospective study in which we evaluated ¹⁸F-FDG PET/CT staging parameters to quantify tumor burdens in patients with stage III or IV NSCLC. The following parameters were evaluated for the whole body (including the primary tumor) and for the primary tumor alone, respectively: maximum standardized uptake volume (wbSUV_max and tuSUV_max); metabolic tumor volume (wbMTV and tuMTV); and total lesion glycolysis (wbTLG and tuTLG). To determine whether the ¹⁸F-FDG PET/CT parameters were associated with overall survival (OS) and progression-free survival (PFS), we evaluated the wbSUV_max/tuSUV_max, wbMTV/tuMTV, and wbTLG/tuTLG ratios.

Results

¹⁸F-FDG PET/CT was performed for staging in 52 patients who were followed for a median of 11.0 months (mean, 11.7 months). The estimated median PFS and OS were 9.6 months and 11.6 months, respectively. In the univariate analysis, OS was found to correlate significantly with wbTLG (hazard ratio [HR] = 1.001; 95% confidence interval [95 CI]: 1.000-1.001; p = 0.0361) and with the wbTLG/tuTLG ratio (HR = 1.705; 95% CI: 1.232-2.362; p = 0.0013). In the multivariate analysis, only the wbTLG/tuTLG ratio was independently associated with OS (HR = 1.660; 95% CI: 1.193-2.310; p = 0.0027).

Conclusion

The wbTLG/tuTLG ratio is an independent prognostic indicator of OS in advanced-stage NSCLC.

PET/CT and the Response to Immunotherapy in Lung Cancer

Objective

In recent years, the introduction of immune checkpoint inhibitors has significantly changed the outcome of patients affected by lung cancer and cutaneous melanoma. Although the clinical advantages, the selection of patients and the evaluation of response to immunotherapy remain unclear, the immune-related Response Evaluation Criteria in Solid Tumor (irRECIST) was proposed as an update of the RECIST criteria for the assessment of response to immunotherapy. However, morphological images cannot predict early response to therapy that represents a challenge in clinical practice. 18F-FDG PET/CT before and after immunotherapy has an indeterminate role, demonstrating ambiguous results due to inflammatory effects secondary to activation of the immune system. The aim of the present review was to analyze the role of PET/CT as a guide for immunotherapy, by analyzing the current status and future perspectives.

Methods

A literature search was conducted in order to select all papers that discussed the role of PET/CT with FDG or other tracers in the evaluation or prediction of response to immunotherapy in lung cancer patients.

Results

Many papers are now available. Many clinical trials have demonstrated the efficacy of immunotherapy in lung cancer patients. FDG PET/CT can be used for the prediction of response to immunotherapy, while its utility for the evaluation of response is not still clearly reported. Moreover, the standardization of FDG PET/CT interpretation is missing and different criteria, such as information, have been investigated until now.

Conclusion

The utility of FDG PET/CT for patients with lung cancer undergoing immunotherapies is still preliminary and not well addressed. New agents for PET are promising, but large clinical trials are mandatory.

Metabolic Strategies for Inhibiting Cancer Development

The tumor microenvironment is a complex mix of cancerous and noncancerous cells (especially immune cells and fibroblasts) with distinct metabolisms. These cells interact with each other and are influenced by the metabolic disorders of the host. In this review, we discuss how metabolic pathways that sustain biosynthesis in cancer cells could be targeted to increase the effectiveness of cancer therapies by limiting the nutrient uptake of the cell, inactivating metabolic enzymes (key regulatory ones or those linked to cell cycle progression), and inhibiting ATP production to induce cell death. Furthermore, we describe how the microenvironment could be targeted to activate the immune response by redirecting nutrients toward cytotoxic immune cells or inhibiting the release of waste products by cancer cells that stimulate immunosuppressive cells. We also examine metabolic disorders in the host that could be targeted to inhibit cancer development. To create future personalized therapies for targeting each cancer tumor, novel techniques must be developed, such as new tracers for positron emission tomography/computed tomography scan and immunohistochemical markers to characterize the metabolic phenotype of cancer cells and their microenvironment. Pending personalized strategies that specifically target all metabolic components of cancer development in a patient, simple metabolic interventions could be tested in clinical trials in combination with standard cancer therapies, such as short cycles of fasting or the administration of sodium citrate or weakly toxic compounds (such as curcumin, metformin, lipoic acid) that target autophagy and biosynthetic or signaling pathways.

The Evolving Role of 18F-FDG PET/CT in Diagnosis and Prognosis Prediction in Progressive Prostate Cancer

Positron emission tomography/computed tomography (PET/CT) is widely used in prostate cancer to evaluate the localized tumor burden and detect symptomatic metastatic lesions early. ¹⁸F-FDG is the most used tracer for oncologic imaging, but it has limitations in detecting early-stage prostate cancer. ⁶⁸Ga-PSMA is a new tracer that has high specificity and sensibility in detecting local and metastatic tumors. But with the progression of prostate cancer, the enhancement of glucose metabolism in progressive prostate cancer provides a chance for ¹⁸F-FDG. This review focuses on PET/CT in the detection and prognosis of prostate cancer, summarizing the literature on ¹⁸F-FDG and ⁶⁸Ga-PSMA in prostate cancer and highlighting that ¹⁸F-FDG has advantages in detecting local recurrence, visceral and lymph node metastases compared to ⁶⁸Ga-PSMA in partial progressive prostate cancer and castration-resistant prostate cancer patients. We emphasize ¹⁸F-FDG PET/CT can compensate for the weakness of ⁶⁸Ga-PSMA PET/CT in progressive prostate cancer.

Summary concordance index for meta-analysis of prognosis studies with a survival outcome

In prognosis studies to evaluate association between a continuous biomarker and a survival outcome, investigators often classify subjects into two subclasses of the high- and low-expression groups and apply simple survival analysis techniques of the Kaplan-Meier method and the logrank test. The high- and low-expressions are defined according to whether or not the observation of the biomarker is higher than the cut-off value, which is heterogeneous across studies. The heterogeneous definitions of the cut-off value make it difficult to apply the standard meta-analysis techniques. We propose a method to estimate the concordance index for a survival outcome synthesizing published prognosis studies, in which the Kaplan-Meier estimates for the high- and low-expression groups are reported. We illustrate our proposed method with a real dataset for meta-analysis of prognosis studies evaluating Ki-67 in early breast cancer and evaluate its performance with a simulation study.

Response Prediction and Evaluation Using PET in Patients with Solid Tumors Treated with Immunotherapy

Simple Summary

In cancer treatment, immunotherapy is increasingly becoming important as a component of first-line treatment and has improved the prognosis of patients since its introduction. A large group of patients, however, do not respond to immunotherapy, and predicting a treatment response remains challenging. Furthermore, evaluating a response using conventional computed tomography (CT) scans is not straightforward due to the different mechanism of action of immunotherapy compared to chemotherapy. This review provides an overview of positron emission tomography (PET) in predicting and evaluating treatment response to immunotherapy.

Abstract

In multiple malignancies, checkpoint inhibitor therapy has an established role in the first-line treatment setting. However, only a subset of patients benefit from checkpoint inhibition, and as a result, the field of biomarker research is active. Molecular imaging with the use of positron emission tomography (PET) is one of the biomarkers that is being studied. PET tracers such as conventional ¹⁸F-FDG but also PD-(L)1 directed tracers are being evaluated for their predictive power. Furthermore, the use of artificial intelligence is under evaluation for the purpose of response prediction. Response evaluation during checkpoint inhibitor therapy can be challenging due to the different response patterns that can be observed compared to traditional chemotherapy. The additional information provided by PET can potentially be of value to evaluate a response early after the start of treatment and provide the clinician with important information about the efficacy of immunotherapy. Furthermore, the use of PET to stratify between patients with a complete response and those with a residual disease can potentially guide clinicians to identify patients for which immunotherapy can be discontinued and patients for whom the treatment needs to be escalated. This review provides an overview of the use of positron emission tomography (PET) to predict and evaluate treatment response to immunotherapy.

Understanding the Central Role of Citrate in the Metabolism of Cancer Cells and Tumors: An Update

Citrate plays a central role in cancer cells’ metabolism and regulation. Derived from mitochondrial synthesis and/or carboxylation of α-ketoglutarate, it is cleaved by ATP-citrate lyase into acetyl-CoA and oxaloacetate. The rapid turnover of these molecules in proliferative cancer cells maintains a low-level of citrate, precluding its retro-inhibition on glycolytic enzymes. In cancer cells relying on glycolysis, this regulation helps sustain the Warburg effect. In those relying on an oxidative metabolism, fatty acid β-oxidation sustains a high production of citrate, which is still rapidly converted into acetyl-CoA and oxaloacetate, this latter molecule sustaining nucleotide synthesis and gluconeogenesis. Therefore, citrate levels are rarely high in cancer cells. Resistance of cancer cells to targeted therapies, such as tyrosine kinase inhibitors (TKIs), is frequently sustained by aerobic glycolysis and its key oncogenic drivers, such as Ras and its downstream effectors MAPK/ERK and PI3K/Akt. Remarkably, in preclinical cancer models, the administration of high doses of citrate showed various anti-cancer effects, such as the inhibition of glycolysis, the promotion of cytotoxic drugs sensibility and apoptosis, the neutralization of extracellular acidity, and the inhibition of tumors growth and of key signalling pathways (in particular, the IGF-1R/AKT pathway). Therefore, these preclinical results support the testing of the citrate strategy in clinical trials to counteract key oncogenic drivers sustaining cancer development and resistance to anti-cancer therapies.

The diagnostic and predictive efficacy of 18F-FDG PET/CT metabolic parameters for EGFR mutation status in non-small-cell lung cancer: A meta-analysis

PURPOSE

To investigate the predictive performance of the maximum standardized uptake value (SUV_max) and mean standardized uptake value (SUV_mean) of primary lesions based on 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) for EGFR mutation status in patients with non-small cell lung cancer (NSCLC).

METHODS

The PubMed/Medline, Embase, Cochrane Library and Web of Science databases were searched as of January 1, 2021. Studies whose reported data could be used to construct contingency tables were included. Study characteristics were extracted, and methodological quality assessment was conducted by two separate reviewers using the Quality Assessment of Diagnostic Accuracy Studies. The pooled sensitivity, specificity and area under the summary receiver operating characteristic curve (AUROC) were calculated. The possible causes of heterogeneity were analysed by meta-regression.

RESULTS

The 18 included studies had a total of 4024 patients. The majority of the studies showed a low to unclear risk of bias and concerns of applicability. For differentiating EGFR-mutant NSCLC from wild-type NSCLC, the pooled sensitivity and specificity were 71 % and 60 % for SUV_max and 64 % and 63 % for SUV_mean, respectively. The summary AUROCs of SUV_max and SUV_mean were 0.69 (95 % CI, 0.65-0.73) and 0.68 (95 % CI, 0.64-0.72), respectively. The meta-regression analysis indicated that blindness to EGFR mutation test results, the number of readers and the number of PET/CT scanners were possible causes of heterogeneity.

CONCLUSIONS

Our meta-analysis implied that SUV_max and SUV_mean of primary lesions from ¹⁸F-FDG PET/CT harboured moderate predictive efficacy for the EGFR mutation status of NSCLC.

Prognostic role of standard uptake value according to pathologic features of lung adenocarcinoma

OBJECTIVE

To evaluate the influence of lung adenocarcinoma second predominant pattern on the maximal standard uptake value (SUVmax) and its prognostic effect in different histologic groups.

METHODS

We retrospectively collected surgically resected pathologic stage I and II lung adenocarcinoma from nine European institutions. Only patients who underwent preoperative PET-CT and with available information regarding SUVmax of T (SUVmaxT) and N1 (SUVmaxN1) component were included.

RESULTS

We enrolled 344 patients with lung adenocarcinoma. SUVmaxT did not show any significant relation according to the second predominant pattern (p = 0.139); this relationship remained nonsignificant in patients with similar predominant pattern. SUVmaxT influenced the disease-free survival in the whole cohort (p = 0.002) and in low- and intermediate-grade predominant pattern groups (p = 0.040 and p = 0.008, respectively). In the high-grade predominant pattern cohort and in the pathologic N1 cases, SUVmaxT lost its prognostic power. SUVmaxN1 did not show any significant correlation with predominant and second predominant patterns and did not have any prognostic impact on DFS.

CONCLUSIONS

SUVmaxT is influenced only by the adenocarcinoma predominant pattern, but not by second predominant pattern. Concurrently, in high-grade predominant pattern and pN1 group the prognostic power of SUVmaxT becomes nonsignificant.

Treatment Intensification in Locally Advanced/Unresectable NSCLC Through Combined Modality Treatment and Precision Dose Escalation

The best survival for patients with unresectable, locally advanced NSCLC is currently achieved through concurrent chemoradiation followed by durvalumab for a year. Despite the best standard of care treatment, the majority of patients still develop disease recurrence, which could be distant and/or local. Trials continue to try and improve outcomes for patients with unresectable NSCLC, typically through treatment intensification, with the addition of more systemic agents, or more radiation dose to the tumor. Although RTOG 0617 showed that uniform dose escalation across an unselected population of patients undergoing chemoradiation is not beneficial, efforts continue to select patients and tumor subsets that are likely to benefit from dose escalation. This review describes some of the ongoing therapeutic trials in unresectable NSCLC, with an emphasis on quantitative imaging and precision radiation dose escalation.

A PET/CT volumetric parameter predicts prognosis of non-small cell lung cancer treated using preoperative chemoradiotherapy and surgery: A retrospective case series study

The purpose of the present study was to clarify whether positron emission tomography/computed tomography (PET/CT) volumetric parameters were prognostic predictors of non-small cell lung cancer (NSCLC) treatment in patients who had undergone preoperative concurrent chemoradiotherapy (CCRT) and surgery. In the present study, retrospectively surveyed the data of patients with NSCLC who underwent preoperative CCRT and surgery at Okayama University Hospital (Okayama, Japan) between April 2006 and March 2018. The maximum standardized uptake value (SUV_max) and volumetric parameters, including metabolic tumor volume (MTV) and total lesion glycolysis (TLG), were calculated using PET/CT and the percentage decrease (Δ) in each parameter value post-CCRT. The SUV_max threshold for defining MTV was set at 2.5. Furthermore, the association between survival and PET parameter values was analyzed. A total of 52 patients were included in the present study. The median follow-up period was 50.65 months. In univariate analysis, ΔTLG was identified to be a significant predictor of progression-free survival (PFS; P=0.03). The 5-year PFS rates were 48.6 and 76.6% for patients with low ΔTLG and high ΔTLG, respectively. High ΔTLG was indicative of a higher overall survival rate (P=0.08). The present results suggest that ΔTLG calculated using PET/CT is a prognostic predictor of NSCLC treated using preoperative CCRT and surgery, and may help physicians determine treatment strategies.

Evaluation of tumor response after stereotactic body radiation therapy for lung cancer: Role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography

BACKGROUND

Early identification of patients who fail to lung stereotactic body radiation therapy (SBRT) is vital as they can benefit from salvage therapy. Main guidelines recommend computed tomography (CT) to assess response and use of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/CT only when a local recurrence is suspected in CT. The pattern of radiation-induced lung injury caused by SBRT is different from changes seen after conventional radiation therapy in terms of extent, time of manifestation, and morphologic characteristics, and knowing this is crucial for proper monitoring of the tumor response. In certain cases, it may be difficult to differentiate response from progression or recurrence on CT and, in addition, some changes in CT take a long time to evolve before they are considered suspicious, making early diagnosis difficult. Metabolic changes often precede morphological changes, so 18F-FDG PET/CT quantitative and qualitative metabolic criteria can be useful in assessing early response and detecting relapses. However, the optimal practice for follow-up remains unclear and there is an active search for imaging markers for recurrent disease, including CT texture analysis, biomarker assays, new PET/CT isotopes, and magnetic resonance imaging.

AIM

The aim of the study was to review the radiological changes that are objectified after pulmonary SBRT and the metabolic changes in 1F-FDG PET/CT, to assess the usefulness of following up patients with 18F-FDG PET/CT.

RELEVANCE FOR PATIENTS

At present, the evaluation of response and diagnosis of relapse after SBRT are difficult and the incorporation of routine 18F-FDG PET/CT may have value in early diagnosis of relapse when the patient may still benefit from rescue treatment.

Prognostic factors and clinical outcomes after stereotactic radiotherapy for primary lung tumors

Aim

To characterize the population treated with SBRT for early-stage primary lung tumors in our institution, determine their outcomes, and identify potential prognosis factors.

Background

Stereotactic radiotherapy (SBRT) is an alternative treatment for inoperable patients with early-stage lung cancer. It confers a local control rate around 90% at 3 years, and 2-3 year overall survival rates of 43-60% in this population.

Materials and methods

We retrospectively analyzed all patients treated in our department between 2012 and 2017 and evaluated local progression-free survival (L-PFS), nodal or distant progression-free survival (ND-PFS), global progression-free survival (G-PFS), overall survival (OS), and disease specific survival (DSS). Univariate (UVA) and multivariate (MVA) models were built to assess the influence of each variable.

Results

We identified 218 patients with 233 tumors. Most were male (78.9%) with a median age of 73 years. Median follow-up was 22 months. At 18 months, L-PFS was 93.7%, ND-PFS was 82.2%, G-PFS was 76.0%, DSS was 90.5%, and OS was 78.0% in ≤ T2 tumors. On UVA, T2 tumors were associated with lower L-PFS, G-PFS and DSS than T1, with no significant impact on ND-PFS or OS, an effect that persisted on MVA. On UVA, L-PFS and G-PFS were negatively influenced by female gender and a 5-fraction schedule was associated with worse G-PFS, which was not confirmed on MVA.

Conclusion

Our local and distant control rates and survival were similar to those previously reported. On MVA, T2 tumors displayed lower L-PFS, G-PFS and DSS, with no difference in OS.

Sensitivity analysis of FDG PET tumor voxel cluster radiomics and dosimetry for predicting mid-chemoradiation regional response of locally advanced lung cancer

We investigated the sensitivity of regional tumor response prediction to variability in voxel clustering techniques, imaging features, and machine learning algorithms in 25 patients with locally advanced non-small cell lung cancer (LA-NSCLC) enrolled on the FLARE-RT clinical trial. Metabolic tumor volumes (MTV) from pre-chemoradiation (PETpre) and mid-chemoradiation fluorodeoxyglucose-positron emission tomography (FDG PET) images (PETmid) were subdivided into K-means or hierarchical voxel clusters by standardized uptake values (SUV) and 3D-positions. MTV cluster separability was evaluated by CH index, and morphologic changes were captured by Dice similarity and centroid Euclidean distance. PETpre conventional features included SUVmean, MTV/MTV cluster size, and mean radiation dose. PETpre radiomics consisted of 41 intensity histogram and 3D texture features (PET Oncology Radiomics Test Suite) extracted from MTV or MTV clusters. Machine learning models (multiple linear regression, support vector regression, logistic regression, support vector machines) of conventional features or radiomic features were constructed to predict PETmid response. Leave-one-out-cross-validated root-mean-squared-error (RMSE) for continuous response regression (ΔSUVmean) and area-under-receiver-operating-characteristic-curve (AUC) for binary response classification were calculated. K-means MTV 2-clusters (MTVhi, MTVlo) achieved maximum CH index separability (Friedman p < 0.001). Between PETpre and PETmid, MTV cluster pairs overlapped (Dice 0.70-0.87) and migrated 0.6-1.1 cm. PETmid ΔSUVmean response prediction was superior in MTV and MTVlo (RMSE = 0.17-0.21) compared to MTVhi (RMSE = 0.42-0.52, Friedman p < 0.001). PETmid ΔSUVmean response class prediction performance trended higher in MTVlo (AUC = 0.83-0.88) compared to MTVhi (AUC = 0.44-0.58, Friedman p = 0.052). Models were more sensitive to MTV/MTV cluster regions (Friedman p = 0.026) than feature sets/algorithms (Wilcoxon signed-rank p = 0.36). Top-ranked radiomic features included GLZSM-LZHGE (large-zone-high-SUV), GTSDM-CP (cluster-prominence), GTSDM-CS (cluster-shade) and NGTDM-CNT (contrast). Top-ranked features were consistent between MTVhi and MTVlo cluster pairs but varied between MTVhi-MTVlo clusters, reflecting distinct regional radiomic phenotypes. Variability in tumor voxel cluster response prediction can inform robust radiomic target definition for risk-adaptive chemoradiation in patients with LA-NSCLC. FLARE-RT trial: NCT02773238.

[Formula: see text]: deep learning-based radiomics for the time-to-event outcome prediction in lung cancer

Hand-crafted radiomics has been used for developing models in order to predict time-to-event clinical outcomes in patients with lung cancer. Hand-crafted features, however, are pre-defined and extracted without taking the desired target into account. Furthermore, accurate segmentation of the tumor is required for development of a reliable predictive model, which may be objective and a time-consuming task. To address these drawbacks, we propose a deep learning-based radiomics model for the time-to-event outcome prediction, referred to as DRTOP that takes raw images as inputs, and calculates the image-based risk of death or recurrence, for each patient. Our experiments on an in-house dataset of 132 lung cancer patients show that the obtained image-based risks are significant predictors of the time-to-event outcomes. Computed Tomography (CT)-based features are predictors of the overall survival (OS), with the hazard ratio (HR) of 1.35, distant control (DC), with HR of 1.06, and local control (LC), with HR of 2.66. The Positron Emission Tomography (PET)-based features are predictors of OS and recurrence free survival (RFS), with hazard ratios of 1.67 and 1.18, respectively. The concordance indices of [Formula: see text], [Formula: see text], and [Formula: see text] for predicting the OS, DC, and RFS show that the deep learning-based radiomics model is as accurate or better in predicting predefined clinical outcomes compared to hand-crafted radiomics, with concordance indices of [Formula: see text], [Formula: see text], and [Formula: see text], for predicting the OS, DC, and RFS, respectively. Deep learning-based radiomics has the potential to offer complimentary predictive information in the personalized management of lung cancer patients.

Perspective: Do Fasting, Caloric Restriction, and Diets Increase Sensitivity to Radiotherapy? A Literature Review

Caloric starvation, as well as various diets, has been proposed to increase the oxidative DNA damage induced by radiotherapy (RT). However, some diets could have dual effects, sometimes promoting cancer growth, whereas proposing caloric restriction may appear counterproductive during RT considering that the maintenance of weight is a major factor for the success of this therapy. A systematic review was performed via a PubMed search on RT and fasting, or caloric restriction, ketogenic diet (>75% of fat-derived energy intake), protein starvation, amino acid restriction, as well as the Warburg effect. Twenty-six eligible original articles (17 preclinical studies and 9 clinical noncontrolled studies on low-carbohydrate, high-fat diets popularized as ketogenic diets, representing a total of 77 patients) were included. Preclinical experiments suggest that a short period of fasting prior to radiation, and/or transient caloric restriction during treatment course, can increase tumor responsiveness. These regimens promote accumulation of oxidative lesions and insufficient repair, subsequently leading to cancer cell death. Due to their more flexible metabolism, healthy cells should be less sensitive, shifting their metabolism to support survival and repair. Interestingly, these regimens might stimulate an acute anticancer immune response, and may be of particular interest in tumors with high glucose uptake on positron emission tomography scan, a phenotype associated with poor survival and resistance to RT. Preclinical studies with ketogenic diets yielded more conflicting results, perhaps because cancer cells can sometimes metabolize fatty acids and/or ketone bodies. Randomized trials are awaited to specify the role of each strategy according to the clinical setting, although more stringent definitions of proposed diet, nutritional status, and consensual criteria for tumor response assessment are needed. In conclusion, dietary interventions during RT could be a simple and medically economical and inexpensive method that may deserve to be tested to improve efficiency of radiation.

18F-FDG PET/CT total lesion glycolysis is associated with circulating tumor cell counts in patients with stage I to IIIA non-small cell lung cancer

Background

In non-small cell lung cancer (NSCLC), ¹⁸F-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) uptake determined by PET and presence of circulating tumor cells (CTCs) in the peripheral blood independently predict outcomes. For ¹⁸F-FDG PET/CT staging interpretation, standardized uptake values (SUV_max/avg) are routinely used in clinical reporting. The goal was to investigate whether ¹⁸F-FDG uptake measured by SUV_max/avg, but also measures of metabolic tumor volume (MTV) and total lesion glycolysis (TLG) (MTV × SUV_avg), are associated with CTCs.

Methods

Prospectively, 7.5 mL blood was drawn from NSCLC patients at the time of staging 18F-FDG PET/CT and from healthy control subjects. CTCs were identified by immunofluorescent staining (CK8/18/19^pos/EpCAM^pos/CD45^neg/DAPI^pos nucleus). ¹⁸F-FDG PET/CTs were analyzed for SUV_max, SUV_avg, MTV, and TLG.

Results

In 16 NSCLC patients with stage I–IIIA, MTV and TLG, in contrast to SUV_max and SUV_avg, were positively associated with CTCs (linear regression analysis). No CTCs were detectable in 20 healthy control subjects.

Conclusions

This pilot study demonstrates that ¹⁸F-FDG PET/CT TLG correlates with CTCs in NSCLC patients without distant metastases. TLG might be a more appropriate marker for hematogenous micrometastatic potential than SUVs.