Positron-emission tomography in prognostic and therapeutic assessment of lung cancer: systematic review

On the Ocean of Biomarkers for the Precise Diagnosis and Prognosis of Lung Diseases

Bronchoalveolar lavage fluid (BALF) has long been used for diagnosing various lung diseases through its cellular components. However, the clinical utility of biomolecules in the BALF remains largely unexplored. Recently, mass spectrometry-based proteomics has been applied to profile the BALF proteomes to identify novel biomarkers for lung diseases. This review discusses the current progress in the field of BALF proteomics and highlights its potential as a valuable source of biomarkers for different lung diseases. Additionally, we explored the latest advancements and findings from BALF studies. Finally, we address the current limitations and propose future directions and research opportunities to advance the study of BALF.

Predicting PD-L1 in Lung Adenocarcinoma Using 18F-FDG PET/CT Radiomic Features

Background/Objectives: This study aims to retrospectively analyze the clinical and imaging data of 101 patients with lung adenocarcinoma who underwent [18F]FDG PET/CT examination and were pathologically confirmed in the Department of Nuclear Medicine at Peking University Cancer Hospital. This study explores the predictive value and important features of [18F]FDG PET/CT radiomics for PD-L1 expression levels in lung adenocarcinoma patients, assisting in screening patients who may benefit from immunotherapy. Methods: 101 patients with histologically confirmed lung adenocarcinoma who received pre-treatment [18F] FDG PET/CT were included. Among them, 44 patients were determined to be PD-L1 positive and 57 patients were determined to be PD-L1 negative based on immunohistochemical assays. Clinical data, PET/CT radiomics parameters, conventional metabolic parameters, and observed CT characteristics were included in the modeling. Random Forest was used in feature denoising, while Forward Stepwise Regression and the Least Absolute Shrinkage and Selection Operator were used in feature selection. Models based on Tree, Discriminant, Logistic Regression, and Support Vector Machine were trained and evaluatedto explore the value of clinical data, PET/CT radiomics parameters, conventional metabolic parameters, and observed CT characteristics. Results: All models showed some predictive ability in distinguishing PD-L1 positive from PD-L1 negative samples. Among the multimodal imaging, clinical data were incorporated into the models, with clinical stage and gender selected by Forward Stepwise Regression, while clinical stage, smoking history, and gender were selected by LASSO. When incorporating clinical data and thin-section CT-derived images into the models, nodular type, spiculation, and CT Shape Flatness were selected by Forward Stepwise Regression, while nodular type and spiculation were selected by LASSO. When incorporating clinical data, PET/CT radiomics, observed CT characteristics, and conventional metabolic information. Forward Stepwise Regression selected TLGlean, MTV, nodule component, PET Shape Sphericity, while LASSO selected SULmax, MTV, nodular type, PET Shape Sphericity, and spiculation. Conclusions: The integration of clinical data, PET/CT radiomics, and conventional metabolic parameters effectively predicted PD-L1 expression, thereby assisting the selection of patients who would benefit from immunotherapy. Observed CT characteristics and conventional metabolic information play an important role in predicting PD-L1 expression levels.

Proposal for novel definition of radiologically less-invasive clinical stage IA solid predominant lung adenocarcinoma using the maximum standardized uptake value

OBJECTIVE

This study aimed to evaluate the possibility of defining new imaging criteria to predict less-invasive clinical (c)-stage IA2-IA3 solid predominant lung adenocarcinoma using the maximum standardized uptake value (SUVmax) as the cutoff value.

METHODS

Consecutive 364 patients who underwent anatomical resection with mediastinal lymphadenectomy and positron emission tomography for c-stage IA2-IA3 solid predominant lung adenocarcinoma with a tumor diameter < 3 cm were retrospectively evaluated. Less-invasive cancer was defined as the absence of nodal involvement, lymphovascular or pleural invasion, or spread through air spaces. The SUVmax cutoff value was determined based on the specificity of the receiver operating characteristic curve.

RESULTS

228 were pure-solid tumors, and 136 were part-solid tumors. 212 were c-stage IA2 and 152 were c-stage IA3. When the SUVmax was set at a cutoff value of 2.2, sensitivity and specificity were 33.0% and 97.6%, respectively, and it was possible to secure the sensitivity by more than 30% with high specificity among the solid predominant tumors. When the SUVmax was set at a cutoff value of 2.2, sensitivity and specificity were 40.7% and 95.7%, respectively, in whole tumor diameter ≤ 2 cm, and 27.0% and 99.0%, respectively in whole tumor diameter between 2 and 3 cm. When the SUVmax was set at a cutoff value of 2.2, sensitivity and specificity were 45.8% and 96.6%, respectively, in part-solid tumors, and 17.8% and 97.8%, respectively in pure-solid tumors.

CONCLUSION

Setting the SUVmax as cutoff value could predict pathologically less-invasive cancers in c-stage IA2-IA3 solid predominant lung adenocarcinoma.

Advancements in lung cancer: a comprehensive perspective on diagnosis, staging, therapy and follow-up from the SAKK Working Group on Imaging in Diagnosis and Therapy Monitoring

In 2015, around 4400 individuals received a diagnosis of lung cancer, and Switzerland recorded approximately 3200 deaths related to lung cancer. Advances in detection, such as lung cancer screening and improved treatments, have led to increased identification of early-stage lung cancer and higher chances of long-term survival. This progress has introduced new considerations in imaging, emphasising non-invasive diagnosis and characterisation techniques like radiomics. Treatment aspects, such as preoperative assessment and the implementation of immune response evaluation criteria in solid tumours (iRECIST), have also seen advancements. For those undergoing curative treatment for lung cancer, guidelines propose follow-up with computed tomography (CT) scans within a specific timeframe. However, discrepancies exist in published guidelines, and there is a lack of universally accepted recommendations for follow-up procedures. This white paper aims to provide a certain standard regarding the use of imaging on the diagnosis, staging, treatment and follow-up of patients with lung cancer.

Liquid Biopsy and 18F-FDG PET/CT Derived Parameters as Predictive Factors of Osimertinib Treatment in Advanced EGFR-Mutated NSCLC

OBJECTIVES

Despite the outstanding results achieved by osimertinib for the treatment of advanced EGFR-mutated NSCLC, the development of resistance is almost inevitable. While molecular mechanism responsible for osimertinib resistance are being mostly revealed, the definition of predictive biomarkers is crucial in order to identify patients at higher risk of progression and optimize treatment strategy.

MATERIALS AND METHODS

This is a prospective single-center study aimed to assess the potential role of liquid biopsy and 18F-FDG PET/CT derived metabolic parameters as noninvasive predictive biomarkers of osimertinib outcomes in advanced EGFR-mutated NSCLC patients. Patients underwent blood samples for ctDNA analysis at baseline, after 15 days and 1 month (t1) of osimertinib. 18F-FDG PET/CT was performed at baseline and after 1 month of osimertinib.

RESULTS

Seventy-two advanced EGFR-mutated NSCLC patients treated with osimertinib in first (n = 63) and in second-line (n = 9) were prospectively enrolled. Baseline positive shedding status was significantly associated with a shorter progression-free survival (PFS) (9.5 vs. 29.2 months, P = .031). Early metabolic response (MR) led to improved PFS (16.8 vs. 5.5 months, P = .038) and OS (35.2 vs. 15.3 months, P = .047). Early MR was significantly correlated with subsequent radiologic response (P = .010). All 18F-FDG PET/CT baseline parameters were significantly related to baseline EGFR activating mutation allele frequency. Both clearance and no detection of EGFR at t1 were significantly associated with MR (P = .001 and P = .004, respectively).

CONCLUSION

Molecular and 18F-FDG PET/CT derived metabolic parameters might represent a useful tool to predict osimertinib outcome in advanced EGFR-mutated NSCLC patients.

Radiomic analysis will add differential diagnostic value of benign and malignant pulmonary nodules: a hybrid imaging study based on [18F]FDG and [18F]FLT PET/CT

PURPOSE

To investigate the clinical value of radiomic analysis on [18F]FDG and [18F]FLT PET on the differentiation of [18F]FDG-avid benign and malignant pulmonary nodules (PNs).

METHODS

Data of 113 patients with inconclusive PNs based on preoperative [18F]FDG PET/CT who underwent additional [18F]FLT PET/CT scans within a week were retrospectively analyzed in the present study. Three methods of analysis including visual analysis, radiomic analysis based on [18F]FDG PET/CT images alone, and radiomic analysis based on dual-tracer PET/CT images were evaluated for differential diagnostic value of benign and malignant PNs.

RESULTS

A total of 678 radiomic features were extracted from volumes of interest (VOIs) of 123 PNs. Fourteen valuable features were thereafter selected. Based on a visual analysis of [18F]FDG PET/CT images, the diagnostic accuracy, sensitivity, and specificity were 61.6%, 90%, and 28.8%, respectively. For the test set, the area under the curve (AUC), sensitivity, and specificity of the radiomic models based on [18F]FDG PET/CT plus [18F]FLT signature were equal or better than radiomics based on [18F]FDG PET/CT only (0.838 vs 0.810, 0.778 vs 0.778, 0.750 vs 0.688, respectively).

CONCLUSION

Radiomic analysis based on dual-tracer PET/CT images is clinically promising and feasible for the differentiation between benign and malignant PNs.

CLINICAL RELEVANCE STATEMENT

Radiomic analysis will add differential diagnostic value of benign and malignant pulmonary nodules: a hybrid imaging study based on [18F]FDG and [18F]FLT PET/CT.

KEY POINTS

• Radiomics brings new insights into the differentiation of benign and malignant pulmonary nodules beyond the naked eyes. • Dual-tracer imaging shows the biological behaviors of cancerous cells from different aspects. • Radiomics helps us get to the histological view in a non-invasive approach.

Evaluation of treatment response by Hopkins criteria on 18 F FDG PET-CT in patients of non-small cell lung cancer and its comparison with PERCIST response criteria

AIM

To assess treatment response on FDG PET-CT in NSCLC patients by visual Hopkins score compared to PERCIST criteria and its potential for prognostication (or its correlation with survival).

METHODS

Forty-four NSCLC patients with baseline and post-treatment FDG PET-CT scans were included, and interpreted using Hopkins and PERCIST criteria classifying patients into responders and non-responders. PERCIST-based CMR and PMR, and Hopkins Scores 1,2,3 were classified responders. PERCIST-based SD and PD and Hopkins scores 4,5 were classified as non-responders. Patients were followed upto 24 months after treatment completion. Cohen kappa for inter-criteria agreement and Kaplan Meir curve for overall survival (OS) analysis done.

RESULTS

Out of 44 patients, PERCIST classified 27 (61.3%) as responders and 17 (38.6%) as non-responders, whereas Hopkins classified 12 patients (27.3%) as responders and 32 (72.7%) as non-responders. Inter-criteria agreement was low (kappa=0.19) with discordance in 45.5% of patients. Eighteen of 20 discordant cases were non-responders on Hopkins and responders on PERCIST, of which 88.8% were non-responders on follow-up as predicted by Hopkins. PERCIST responders had OS of 96.4% and 64.3% at 9 and 24 months, respectively, while non-responders OS was 93.5% and 40.2% at 9 and 24 months, respectively ( P -value = 0.049). However, responders on Hopkins had OS of 100% at 24 months, whereas non-responders had OS of 93.5% and 51.5% at 9 and 24 months, respectively ( P -value = 0.232).

CONCLUSION

Semi-quantitative PERCIST and visual Hopkins criteria show low inter-criteria agreement, with visual criteria better-predicting survival in patients of NSCLC.

Prognostic role of preoperative fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography with an image-based harmonization technique: A multicenter retrospective study

Objectives

Despite the prognostic impacts of preoperative fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography examination, fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography-based prognosis prediction has not been used clinically because of the disparity in data between institutions. By applying an image-based harmonized approach, we evaluated the prognostic roles of fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters in clinical stage I non-small cell lung cancer.

Methods

We retrospectively examined 495 patients with clinical stage I non-small cell lung cancer who underwent fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography examinations before pulmonary resection between 2013 and 2014 at 4 institutions. Three different harmonization techniques were applied, and an image-based harmonization, which showed the best-fit results, was used in the further analyses to evaluate the prognostic roles of fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters.

Results

Cutoff values of image-based harmonized fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters, maximum standardized uptake, metabolic tumor volume, and total lesion glycolysis were determined using receiver operating characteristic curves that distinguish pathologic high invasiveness of tumors. Among these parameters, only the maximum standardized uptake was an independent prognostic factor in recurrence-free and overall survivals in univariate and multivariate analyses. High image-based maximum standardized uptake value was associated with squamous histology or lung adenocarcinomas with higher pathologic grades. In subgroup analyses defined by ground-glass opacity status and histology or by clinical stages, the prognostic impact of image-based maximum standardized uptake value was always the highest compared with other fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters.

Conclusions

The image-based fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography harmonization was the best fit, and the image-based maximum standardized uptake was the most important prognostic marker in all patients and in subgroups defined by ground-glass opacity status and histology in surgically resected clinical stage I non-small cell lung cancers.

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.

Relationship between Systemic Inflammatory Markers, GLUT1 Expression, and Maximum 18F-Fluorodeoxyglucose Uptake in Non-Small Cell Lung Carcinoma and Their Prognostic Significance

BACKGROUND

Factors involved in inflammation and cancer interact in various ways with each other, and biomarkers of systemic inflammation may have a prognostic value in cancer. Glucose transporter 1 (GLUT1) plays a pivotal role in glucose transport and metabolism and it is aberrantly expressed in various cancer types. We evaluated the differential expression of GLUT1, along with 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) in non-small-cell lung cancer (NSCLC), and then analyzed their prognostic significance.

METHODS

A total of 163 patients with resectable NSCLC were included in this study. Tumor sections were immunohistochemically stained for GLUT1 and GLUT3. Maximum standardized uptake value (SUV_max) was measured by preoperative FDG-PET, and neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and lymphocyte-monocyte ratio (LMR) were derived from pretreatment blood count.

RESULTS

GLUT1 and GLUT3 was positively expressed in 74.8% and 6.1% of the NSCLC tissues, respectively. GLUT1 expression was significantly correlated with squamous cell carcinoma histology, poor differentiation, high pathologic stage, old age, male, smoking, and high SUV_max (>7) (all p < 0.05). The squamous cell carcinoma and smoker group also showed significantly higher SUV_max (both p < 0.001). Systemic inflammation markers, including NLR, PLR, and LMR, were positively correlated with high SUV_max (all p < 0.05). High GLUT1 expression, high SUV_max, high NLR, and low LMR, were significantly associated with poor overall survival in patients with NSCLC. However, in the multivariate survival analysis, LMR was an independent prognostic factor overall (HR 1.86, 95% CI 1.05-3.3) and for the stage I/II cohort (HR 2.3, 95% CI 1.24-4.3) (all p < 0.05).

CONCLUSIONS

Systemic inflammatory markers-NLR, PLR, and LMR are strongly correlated with the SUV_max and are indicators of aggressive tumor behavior. Specifically, LMR is a promising prognostic biomarker in NSCLC patients.

18F-Fluorodeoxyglucose PET/CT for Early Prediction of Outcomes in Patients with Advanced Lung Adenocarcinomas and EGFR Mutations Treated with First-Line EGFR-TKIs

Simple Summary

Epithelial growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are the first-line therapy for patients with advanced-stage lung adenocarcinoma with EGFR mutations. However, 17–31% of these patients do not respond to therapy, making early evaluation of treatment response crucial. This prospective study investigates the value of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) for timely prediction of response and survival of these patients. We evaluated 30 patients with stage IIIB/IV lung adenocarcinomas and EGFR mutations, receiving first-line EGFR-TKI therapy. ¹⁸F-FDG PET/CT was performed before and two weeks after initiation of treatment. Positron Emission Tomography Response Criteria in Solid Tumors served as an independent predictor of non-progressive disease; baseline and change of metabolic tumor volume represented independent predictors of progression-free survival and overall survival, respectively. Therefore, ¹⁸F-FDG PET/CT is an early predictor of outcomes and individual prognosis of patients with stage IIIB/IV lung adenocarcinomas and EGFR mutations receiving first-line EGFR-TKI therapy.

Abstract

This study aims to investigate the role of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in early prediction of response and survival following epithelial growth factor receptor (EGFR)–tyrosine kinase inhibitor (TKI) therapy in patients with advanced lung adenocarcinomas and EGFR mutations. Thirty patients with stage IIIB/IV lung adenocarcinomas and EGFR mutations receiving first-line EGFR-TKIs were prospectively evaluated between November 2012 and May 2015. EGFR mutations were quantified by delta cycle threshold (dCt). ¹⁸F-FDG PET/CT was performed before and 2 weeks after treatment initiation. PET response was assessed based on PET Response Criteria in Solid Tumors (PERCIST). Baseline and percentage changes in the summed standardized uptake value, metabolic tumor volume (bsumMTV and ΔsumMTV, respectively), and total lesion glycolysis of ≤5 target lesions/patient were calculated. The association between parameters (clinical and PET) and non-progression disease after 3 months of treatment in CT based on the Response Evaluation Criteria in Solid Tumors Version 1.1 (nPD_3mo), progression-free survival (PFS), and overall survival (OS) were tested. The median follow-up time was 19.6 months. The median PFS and OS were 12.0 and 25.3 months, respectively. The PERCIST criteria was an independent predictor of nPD_3mo (p = 0.009), dCt (p = 0.014) and bsumMTV (p = 0.014) were independent predictors of PFS, and dCt (p = 0.014) and ΔsumMTV (p = 0.005) were independent predictors of OS. ¹⁸F-FDG PET/CT achieved early prediction of outcomes in patients with advanced lung adenocarcinomas and EGFR mutations receiving EGFR-TKIs.

FDG uptake in PET is associated with the tumor microenvironment in metastatic lymph nodes and prognosis in N2 lung adenocarcinoma

Positron emission tomography is a useful technique for diagnosing lymph node (LN) metastasis. This study aimed to elucidate the association between fluorodeoxyglucose accumulation and the microenvironment in metastatic LNs in lung adenocarcinoma. We retrospectively analyzed 62 patients with surgically resected pathological N2 lung adenocarcinoma who underwent preoperative PET. The maximum standardized uptake value (SUV_max) in the metastatic LNs was measured. Lymph node specimens were immunohistochemically analyzed for CD8⁺, FoxP3⁺, and CD79a⁺ lymphocytes, CD204⁺ tumor‐associated macrophages (TAMs), and alpha‐smooth muscle actin‐positive cancer‐associated fibroblasts (αSMA⁺ CAFs). We compared the clinicopathologic and immunohistochemical characteristics between two groups with high and low LN SUV_max. Using novel 3D hybrid spheroid models, we investigated the change in invasiveness of cancer cells in the presence of CAFs. In the multivariate analyses, LN SUV_max was an independent prognostic factor. The overall survival in the LN SUV_max high group was significantly worse than in the low group (P = .034). In the LN SUV_max high group, metastatic cancer cell invasion of extranodal tissue was more frequent (P = .005) and the number of CD204⁺ TAMs and αSMA⁺ CAFs in metastatic LNs was significantly higher than in the low group (P < .001 and P = .002, respectively). Hybrid spheroid models revealed that cancer cells coexisting with CAFs were more invasive than those without CAFs. Our results indicated a strong association between LN SUV_max and poor prognosis in patients with N2 lung adenocarcinoma. Moreover, LN SUV_max was suggested to be associated with the presence of tumor‐promoting stromal cells in metastatic LNs.

Prognostic Value of 18F-FDG PET/CT Metabolic Parameters in Surgically Treated Stage I Lung Adenocarcinoma Patients

PURPOSE OF THE REPORT

This article aims to explore the prognostic role of 18F-FDG PET/CT metabolic parameters in stage I lung adenocarcinoma patients.

PATIENTS AND METHODS

One hundred eighty pathological stage I lung adenocarcinoma patients were retrospectively reviewed. Semiquantitative analysis of FDG tumor uptake was performed with TrueD software on the Siemens Leonardo workstation. SUVmean and MTV were calculated using SUV threshold of 41% of SUVmax; the total lesion glycolysis (TLG) was calculated as the product of SUVmean and MTV. Correlation was evaluated using Spearman correlation coefficient. Maximally selected rank statistics was performed to detect the optimal cutoff used for dichotomizing each PET parameter (6.5 for SUVmean, 9.6 for SUVmax, and 19.1 for TLG).

RESULTS

Our main finding was the significant correlation between 18F-FDG PET/CT parameters (SUVmean, SUVmax, and TLG) and disease-free survival in pathologic stage I non-small cell lung cancer. SUVmean has the greatest accuracy in recurrence prediction (integrated area under the curve, 0.803; 95% confidence interval, 0.689-0.918). We run the maximally selected rank statistics to provide the classification of observations in 2 groups by a continuous predictor parameter; the free from recurrence rate was significantly greater in patients with SUVmean ≤6.5, SUVmax ≤9.6, and TLG ≤19.1.

CONCLUSIONS

Our research supports the hypothesis that SUVmean, SUVmax, and TLG are well correlated with free from recurrence rate in stage I adenocarcinoma patients, subjected to pulmonary lobectomy. Our findings also indicate these markers as promising prognostic indicators.

Safety and utility of performing CT-guided biopsies of pulmonary lesions that arise after radiotherapy

This study aimed to evaluate the feasibility, safety and usefulness of performing computed tomography (CT)-guided biopsies of pulmonary lesions that arise after radiotherapy. Seventeen patients (14 males and 3 females; median age: 69 years, range: 48-84 years) underwent CT-guided biopsies of pulmonary lesions that occurred in lung regions that had previously been treated with radiotherapy. Three patients underwent CT-guided biopsies twice, and thus, the total number of procedures was 20. We reviewed the subjects' medical records and images, and evaluated the rate for obtaining pathological diagnosis with the biopsy sample, subsequent clinical course, and complications associated with the procedure. In 19 of 20 procedures (95%), the CT-guided biopsy resulted in a pathological diagnosis being obtained. In 14 procedures, the pathological results were consistent with the patients' clinical courses. In the remaining 5 procedures, the lesions were pathologically diagnosed as benign, but they increased in size thereafter; so the lesions were considered to be clinically malignant. The results were considered to represent sampling errors. There were 3 minor complications (slight pneumothorax which did not require drainage) (3/20, 15%), and there were no major complications. In conclusion, performing CT-guided biopsies of pulmonary lesions that arise after radiotherapy appears to be feasible, safe and useful.

A New Prognostic Index Combines the Metabolic Response and RECIST 1.1 to Evaluate the Therapeutic Response in Patients With Non-Small Cell Lung Cancer

Aim: Response Evaluation Criteria in Solid Tumors (RECIST) is occasionally insufficient for evaluation. We proposed a new prognostic index (NPI) that combines the standardized uptake value (SUV), metabolic tumor volume (MTV), and RECIST. Methods: In total, 116 patients with lung cancer who underwent consecutive positron emission tomography-computed tomography prior to and after the initial treatment were included. We formulated the NPI by estimating the hazard ratios of overall survival for ΔMTV, ΔSUVmax, and ΔD (tumor size based on RECIST). Progression-free survival (PFS) and overall survival (OS) were compared between RECIST and the NPI. Results: ROC curve analysis identified two cutoff values based on the NPI (≤ -49.3% and ≥43.4%) to discriminate partial remission (NPR), stable disease (NSD) and progressive disease (NPD). Based on RECIST, survival analysis did not discriminate significantly on either PFS or OS between the PR, SD, and PD groups. However, according to the NPI, PFS and OS differed significantly between the NPR, NSD, and NPD groups (training set: PFS, p = 0.048; OS, p = 0.026; validation set: PFS, p = 0.004; OS, p = 0.023). Moreover, therapeutic response based on NPI was independent prognostic factor for both PFS [NPR as reference, NSD: hazard ratio (HR) 2.04; 95% confidence interval (95% CI) 1.35-3.08; p = 0.001; NPD: HR 6.87; 95% CI 3.03-15.57; p < 0.001] and OS (NPR as reference, NSD: HR 1.64; 95% CI 1.05-2.57; p = 0.031; NPD: HR 3.56; 95% CI 1.59-7.95; p = 0.002). Conclusion: The NPI showed superiority for evaluation of the therapeutic response and survival for patients with non-small cell lung cancer, overcoming the limitations of RECIST.

Association of the Metabolic Score Using Baseline FDG-PET/CT and dNLR with Immunotherapy Outcomes in Advanced NSCLC Patients Treated with First-Line Pembrolizumab

Background: We aimed to assess the clinical utility of a previously published score combining the total metabolic tumor volume (TMTV) on baseline FDG-PET/CT and pretreatment derived from the neutrophils to lymphocytes ratio (dNLR) for prognostication in NSCLC patients undergoing first-line immunotherapy (IT). Methods: In this multicenter retrospective study, 63 advanced NSCLC patients with a PD-L1 tumor proportion score (TPS) ≥50%, who underwent FDG-PET/CT before first-line IT, treated from January 2017 to September 2019, were enrolled. Associations between this score and the progression-free survival (PFS), overall survival (OS), disease control rate (DCR), and overall response rate (ORR) were evaluated. Results: The median (m) PFS and mOS were 7.7 (95% CI 4.9–10.6) and 12.1 (8.6–15.6) months, respectively, and DCR and ORR were 65% and 58%, respectively. mOS was 17.9 months (14.6 not reached) for the good group versus 13.8 (95%CI 8.4–18.9) and 6.6 (CI 2.0–11.2) months for the intermediate and poor groups, respectively. mPFS was 15.1 (95%CI 12.1–20.0) months for the good group versus 5.2 (1.9–8.5) and 1.9 (95%CI 1.3–2.5) months for the intermediate and poor groups, respectively. The poor prognosis group was associated with DCR and ORR (p < 0.05). Conclusions: The metabolic score combining TMTV on the baseline FDG-PET/CT scan and pretreatment dNLR was associated with the survival and response in a cohort of advanced NSCLC patients with ≥50% PD-L1 receiving frontline IT.

Raman spectroscopic discrimination of normal and cancerous lung tissues

Raman spectroscopy is non-destructive method that allows monitoring of biological tissues with minimal intervention. FT-Raman (λ_ex 1064 nm) and NIR-Vis-Raman (λ_ex 785 nm) spectroscopic measurements were used in ex vivo analysis of normal, non-cancerous abnormal and cancerous lung tissues. Spectroscopic discrimination of the lung tissue samples was made by the use of the ratio of characteristic bands and multivariate statistical methods (PCA, LDA). The combination of Raman spectroscopy and multivariate statistics may have a diagnostic potential for recognizing of cancer lesions in lung.

Role of 18F-FDG PET/CT in establishing new clinical and therapeutic modalities in lung cancer. A short review

Lung cancer is a fairly common malignancy. An early diagnosis and a reliable staging and re-staging with the aim to detect both local and distant relapse are of utmost importance in planning the therapeutic management. The imaging diagnostic work-up of patients with lung cancer usually includes conventional imaging (chest X-ray, contrast-enhanced CT, bone scan) and more recently ¹⁸F-FDG PET/CT. Great advances in the management of lung cancer are based on the information provided by ¹⁸F-FDG PET/CT, as it supplies both metabolic and anatomic information (better localisation). There is vast evidence in the literature demonstrating its utility in (a) characterising benign versus malignant solitary nodules, (b) staging and re-staging lung cancer, (c) guiding the type of therapy, (d) monitoring treatment response and (e) predicting outcome. In particular, given its specificity in differentiating ¹⁸F-FDG-avid relapse from post-surgical changes or post-radiation fibrosis (which do not take up ¹⁸F-FDG), PET/CT can detect recurrent disease after initial treatment and (being a whole-body technique) has demonstrated high accuracy in the detection of distant metastases or secondary tumours. In conclusion, ¹⁸F-FDG PET/CT can be considered a highly accurate and reliable method for staging and re-staging lung cancer, and is highly effective in guiding personalised therapies.

Comparison of Natural Course between Thyroid Cancer Nodules and Thyroid Benign Nodules

BACKGROUND

The natural course of thyroid cancer nodules and benign nodules is different. This study was to compare the changes in size between thyroid cancer nodules and thyroid benign nodules. The risk factors associated with the changes of thyroid cancer nodules were assessed.

METHODS

This study contains retrospective observational and prospective analysis. A total of 113 patients with 120 nodules were recruited in the cancer group, and 116 patients with 119 nodules were enrolled in the benign group. Thyroid ultrasonography was performed at least two times at more than 1-year interval.

RESULTS

The mean follow-up durations were 29.5±18.8 months (cancer group) and 31.9±15.8 months (benign group) (P=0.32). The maximum diameter change in length was 0.36±0.97 mm/year in the cancer group and -0.04±0.77 mm/year in the benign group (P<0.01). The volume was significantly increased in the cancer group compared with the benign group (0.06±0.18 mL/year vs. 0.004±0.05 mL/year, respectively, P<0.01; 26.9%±57.9%/year vs. 1.7%±26.0%/year, P<0.01). Initial maximum diameter (β=0.02, P<0.01) and initial volume (β=0.13, P<0.01) were significantly associated with volume change (mL)/year. Initial maximum standardized uptake value did not predict the nodule growth.

CONCLUSION

It is suggested that thyroid cancer nodules progress rapidly compared with benign nodules. Initial size and volume of nodule were independent risk factors for cancer nodule growth.

Higher-order singular value decomposition-based lung parcellation for breathing motion management

Positron emission tomography (PET) imaging of the lungs is confounded by respiratory motion-induced blurring artifacts that degrade quantitative accuracy. Gating and motion-compensated image reconstruction are frequently used to correct these motion artifacts in PET. In the absence of voxel-by-voxel deformation measures, surrogate signals from external markers are used to track internal motion and generate gated PET images. The objective of our work is to develop a group-level parcellation framework for the lungs to guide the placement of markers depending on the location of the internal target region. We present a data-driven framework based on higher-order singular value decomposition (HOSVD) of deformation tensors that enables identification of synchronous areas inside the torso and on the skin surface. Four-dimensional (4-D) magnetic resonance (MR) imaging based on a specialized radial pulse sequence with a one-dimensional slice-projection navigator was used for motion capture under free-breathing conditions. The deformation tensors were computed by nonrigidly registering the gated MR images. Group-level motion signatures obtained via HOSVD were used to cluster the voxels both inside the volume and on the surface. To characterize the parcellation result, we computed correlation measures across the different regions of interest (ROIs). To assess the robustness of the parcellation technique, leave-one-out cross-validation was performed over the subject cohort, and the dependence of the result on varying numbers of gates and singular value thresholds was examined. Overall, the parcellation results were largely consistent across these test cases with Jaccard indices reflecting high degrees of overlap. Finally, a PET simulation study was performed which showed that, depending on the location of the lesion, the selection of a synchronous ROI may lead to noticeable gains in the recovery coefficient. Accurate quantitative interpretation of PET images is important for lung cancer management. Therefore, a guided motion monitoring approach is of utmost importance in the context of pulmonary PET imaging.

Small pulmonary granuloma is often misdiagnosed as lung cancer by positron emission tomography/computer tomography in diabetic patients

OBJECTIVES

A small pulmonary granuloma (SPG) is often misdiagnosed as lung cancer in diabetic patients by positron emission tomography/computed tomography (PET/CT). The present study was conducted to investigate whether diabetes is the influencing factor and to determine other related factors that have an impact on the diagnostic results following PET/CT examination.

METHODS

All clinical, imaging and pathological data of patients diagnosed with pulmonary nodules by PET/CT from January 2004 to December 2017 in our department were collected. Patients with an SPG who were wrongly diagnosed with lung cancer by PET/CT were enrolled (n = 79). The propensity score matching method was used to create a comparable control adenocarcinoma group (n = 395). Maximum standard uptake values, diabetes and fasting blood-glucose (FBG) were determined and analysed.

RESULTS

The average maximum standard uptake values in the 2 groups were comparable (P = 0.801). Maximum standard uptake values in 5 subsections were not significantly different between the 2 groups (P = 0.135). The odds ratio (OR) of 3.326 [95% confidence interval (CI) 1.671-6.623] for diabetes favoured misdiagnosis and was statistically significant (P < 0.001). Furthermore, in patients with high FBG levels (≥7.0 mmol/l), the risk of misdiagnosis of SPG increased significantly compared with normal FBG level (OR 2.601, 95% CI 1.174-5.761; P = 0.015).

CONCLUSIONS

Diabetes and high FBG level were the influencing factors in the false-positive results of lung cancer by PET/CT examination.

Sodium-glucose transporter 2 is a diagnostic and therapeutic target for early-stage lung adenocarcinoma

The diagnostic definition of indeterminate lung nodules as malignant or benign poses a major challenge for clinicians. We discovered a potential marker, the sodium-dependent glucose transporter 2 (SGLT2), whose activity identified metabolically active lung premalignancy and early-stage lung adenocarcinoma (LADC). We found that SGLT2 is expressed early in lung tumorigenesis and is found specifically in premalignant lesions and well-differentiated adenocarcinomas. SGLT2 activity could be detected in vivo by positron emission tomography (PET) with the tracer methyl 4-deoxy-4-[18F] fluoro-alpha-d-glucopyranoside (Me4FDG), which specifically detects SGLT activity. Using a combination of immunohistochemistry and Me4FDG PET, we identified high expression and functional activity of SGLT2 in lung premalignancy and early-stage/low-grade LADC. Furthermore, selective targeting of SGLT2 with FDA-approved small-molecule inhibitors, the gliflozins, greatly reduced tumor growth and prolonged survival in autochthonous mouse models and patient-derived xenografts of LADC. Targeting SGLT2 in lung tumors may intercept lung cancer progression at early stages of development by pairing Me4FDG PET imaging with therapy using SGLT2 inhibitors.

Comparison of perioperative and oncological outcomes between video-assisted segmentectomy and lobectomy for patients with clinical stage IA non-small cell lung cancer: a propensity score matching study

Background

Segmentectomy for lung cancer remains controversial because of the complexity of the procedure and concern about an increased recurrence rate. It is important to compare perioperative and oncological outcomes between segmentectomy and lobectomy.

Methods

From January 2007 to December 2016, 41 segmentectomies by video-assisted thoracic surgery (VATS) and 122 VATS lobectomies for 163 patients with clinical stage IA non-small cell lung cancer (NSCLC) were performed. Clinicopathological factors, including recurrence rate and survival rate, were compared. In order to reduce biases of outcomes, clinicopathological factors were used for propensity score matching (PSM). Then, 41 VATS segmentectomies and 41 lobectomies were selected and further analyzed.

Results

No significant differences were seen between the two groups in age, pulmonary function, comorbidity, operative time, blood loss, chest tube duration days, postoperative stay days, complications, histological type, and multiple primary rate. Smoking index resected number of nodes, tumor size, lymph node metastasis rate, and pathological stage were higher in the lobectomy group than in the segmentectomy group (P<0.05). In the lobectomy group, 16 patients (13.1%) had recurrence, and 2 patients (1.6%) died because of cancer progression. There were no significant differences in the recurrence rate and prognosis between the two groups. In addition, Cox regression analysis suggested that sex, lymph node metastasis, and pathology stage were associated with recurrence (P<0.05), but no factor was an independent prognostic factor. After PSM, the two groups had similar clinicopathological factors, and the type of operation still had no relationship with the recurrence rate or the death rate.

Conclusions

Perioperative and oncological outcomes of VATS segmentectomy are similar to those of VATS lobectomy for patients with clinical stage IA NSCLC. VATS segmentectomy can be considered one of the surgical procedures appropriate for patients with clinical stage IA NSCLC.

Can 18F-FDG PET/CT predict recurrence in patients with cutaneous malignant melanoma?

The aim of this study was to evaluate the prognostic significance of maximum standardized uptake value (SUVmax) of primary cutaneous malignant melanoma (CMM) lesions by 18F-FDG positron emission tomography/ computerized tomography (PET/ CT) in terms of recurrence. Patients, methods: 37 CMM patients (17 men, mean age: 61.7 ± 13.6 years) that underwent PET/CT at presentation were enrolled in this study. Recurrence was determined by histological confirmation or by radiological and clinical follow- up for at least 8 months after curative surgery. Clinical variables such as age, sex, clinical stage, and primary lesion location, thickness, and ulceration, and SUVmax values were analyzed with respect to their usefulness for predicting recurrence. Results: SUVmax was found to be significantly higher in patients with ulceration of primary lesion of CMM (p = 0.004) and in patients with a stage ≥ III (p < 0.000). Patients that experience recurrence had a significantly higher mean SUVmax value (4.9 ± 2.9) than patients who did not (2.1 ± 1.5, p = 0.024). ROC analysis showed that a SUVmax cut-off value 2.2 had high sensitivity (88.9%) and specificity (67.9%) for predicting recurrence. Kaplan-Meier analysis identified ulceration of primary lesion (p = 0.034), stage ≥ III (p = 0.019) and SUVmax ≥ 2.2 (p = 0.002) as predictors of recurrence. However, Cox proportional-hazards analysis showed that only SUVmax (p = 0.025, relative risk 11.063) significantly predicted recurrence. Conclusion: Preoperative SUVmax of primary lesion was found to be the most potent predictor of recurrence in CMM patient. Patients with high SUV max of primary lesion should be followed meticulously for recurrence.

The role of PET/CT as a prognosticator and outcome predictor in lung cancer

Positron emission tomography/computed tomography (PET/CT) is an important imaging tool for management of lung cancer and can be utilized in diagnosis, staging, restaging, treatment planning and evaluating treatment response. In the past decade PET/CT has proven to be beneficial for the prediction of prognosis and outcome. PET findings before and after treatment, the quantitative PET parameters such as standardized uptake value (SUV), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) as well as delayed PET/CT imaging can be used to determine patient prognosis and outcome. Other tracers such as hypoxia and proliferation marker tracers may be used for prognostication. The prognostic factors derived from PET/CT imaging help early development of risk-adapted treatment strategies, which provides cost-effective treatment and leads to improved patient management. Here, we discuss findings of studies related to application of PET/CT in lung cancer as well as some technical updates on quantitative PET/CT in lung cancer.

Inorganic Nanocarriers Overcoming Multidrug Resistance for Cancer Theranostics

Cancer multidrug resistance (MDR) could lead to therapeutic failure of chemotherapy and radiotherapy, and has become one of the main obstacles to successful cancer treatment. Some advanced drug delivery platforms, such as inorganic nanocarriers, demonstrate a high potential for cancer theranostic to overcome the cancer-specific limitation of conventional low-molecular-weight anticancer agents and imaging probes. Specifically, it could achieve synergetic therapeutic effects, demonstrating stronger killing effects to MDR cancer cells by combining the inorganic nanocarriers with other treatment manners, such as RNA interference and thermal therapy. Moreover, the inorganic nanocarriers could provide imaging functions to help monitor treatment responses, e.g., drug resistance and therapeutic effects, as well as analyze the mechanism of MDR by molecular imaging modalities. In this review, the mechanisms involved in cancer MDR and recent advances of applying inorganic nanocarriers for MDR cancer imaging and therapy are summarized. The inorganic nanocarriers may circumvent cancer MDR for effective therapy and provide a way to track the therapeutic processes for real-time molecular imaging, demonstrating high performance in studying the interaction of nanocarriers and MDR cancer cells/tissues in laboratory study and further shedding light on elaborate design of nanocarriers that could overcome MDR for clinical translation.

Quantitative Imaging in Cancer Clinical Trials

As anticancer therapies designed to target specific molecular pathways have been developed, it has become critical to develop methods to assess the response induced by such agents. Although traditional, anatomic CT, and MRI examinations are useful in many settings, increasing evidence suggests that these methods cannot answer the fundamental biologic and physiologic questions essential for assessment and, eventually, prediction of treatment response in the clinical trial setting, especially in the critical period soon after treatment is initiated. To optimally apply advances in quantitative imaging methods to trials of targeted cancer therapy, new infrastructure improvements are needed that incorporate these emerging techniques into the settings where they are most likely to have impact. In this review, we first elucidate the needs for therapeutic response assessment in the era of molecularly targeted therapy and describe how quantitative imaging can most effectively provide scientifically and clinically relevant data. We then describe the tools and methods required to apply quantitative imaging and provide concrete examples of work making these advances practically available for routine application in clinical trials. We conclude by proposing strategies to surmount barriers to wider incorporation of these quantitative imaging methods into clinical trials and, eventually, clinical practice. Our goal is to encourage and guide the oncology community to deploy standardized quantitative imaging techniques in clinical trials to further personalize care for cancer patients and to provide a more efficient path for the development of improved targeted therapies.

Molecular Imaging and Precision Medicine in Lung Cancer

Precision medicine allows tailoring of preventive or therapeutic interventions to avoid the expense and toxicity of futile treatment given to those who will not respond. Lung cancer is a heterogeneous disease functionally and morphologically. PET is a sensitive molecular imaging technique with a major role in the precision medicine algorithm of patients with lung cancer. It contributes to the precision medicine of lung neoplasia by interrogating tumor heterogeneity throughout the body. It provides anatomofunctional insight during diagnosis, staging, and restaging of the disease. It is a biomarker of tumoral heterogeneity that helps direct selection of the most appropriate treatment, the prediction of early response to cytotoxic and cytostatic therapies, and is a prognostic biomarker in patients with lung cancer.

Volumetric and dosimetric comparison of computerised radiotherapy treatment plan between using positron emission tomography/computed tomography (PET/CT) and CT images for target delineation in non-small cell lung cancer patients

Purpose

To compare intensity-modulated radiation therapy (IMRT) treatment planning between using positron emission tomography/computed tomography (PET/CT) and CT for target volume delineation in patients with non-small cell lung cancer (NSCLC).

Methods

Nine NSCLC patients with PET/CT images were enrolled into this study. Gross tumour volumes (GTVs) were delineated by the PET visual assessment (PETvis), the automated PET (PETauto), standardised uptake value (SUV)>2·5 (PET2·5) and threshold 40% SUVmax (PET40), and CT-based method. For each patient, two IMRT treatment plans based on CT and PET/CT delineation were performed. The target coverage and the dose–volume parameters for organs at risk were analysed.

Results

The PETauto referred to PET40 when SUVmax<7 and PET2·5 when SUVmax≥7. The mean GTVs were 15·04, 15·7 and 15·14 cc for PETauto, PETvis and CT based, respectively. The GTV of PETauto was not different from PETvis (p=0·441) and CT based (p=0·594). Based on CT delineation in IMRT planning, only 34% of the cases had sufficient PET/CT planning target volumes coverage, whereas the organs at risk dose parameters were not statistically significant (p>0·05).

Conclusions

PET/CT enables more accurate assessment of tumour delineation for NSCLC, therefore improve target coverage in IMRT plan.

Pulmonary imaging using respiratory motion compensated simultaneous PET/MR

PURPOSE

Pulmonary positron emission tomography (PET) imaging is confounded by blurring artifacts caused by respiratory motion. These artifacts degrade both image quality and quantitative accuracy. In this paper, the authors present a complete data acquisition and processing framework for respiratory motion compensated image reconstruction (MCIR) using simultaneous whole body PET/magnetic resonance (MR) and validate it through simulation and clinical patient studies.

METHODS

The authors have developed an MCIR framework based on maximum a posteriori or MAP estimation. For fast acquisition of high quality 4D MR images, the authors developed a novel Golden-angle RAdial Navigated Gradient Echo (GRANGE) pulse sequence and used it in conjunction with sparsity-enforcing k-t FOCUSS reconstruction. The authors use a 1D slice-projection navigator signal encapsulated within this pulse sequence along with a histogram-based gate assignment technique to retrospectively sort the MR and PET data into individual gates. The authors compute deformation fields for each gate via nonrigid registration. The deformation fields are incorporated into the PET data model as well as utilized for generating dynamic attenuation maps. The framework was validated using simulation studies on the 4D XCAT phantom and three clinical patient studies that were performed on the Biograph mMR, a simultaneous whole body PET/MR scanner.

RESULTS

The authors compared MCIR (MC) results with ungated (UG) and one-gate (OG) reconstruction results. The XCAT study revealed contrast-to-noise ratio (CNR) improvements for MC relative to UG in the range of 21%-107% for 14 mm diameter lung lesions and 39%-120% for 10 mm diameter lung lesions. A strategy for regularization parameter selection was proposed, validated using XCAT simulations, and applied to the clinical studies. The authors' results show that the MC image yields 19%-190% increase in the CNR of high-intensity features of interest affected by respiratory motion relative to UG and a 6%-51% increase relative to OG.

CONCLUSIONS

Standalone MR is not the traditional choice for lung scans due to the low proton density, high magnetic susceptibility, and low T2 (∗) relaxation time in the lungs. By developing and validating this PET/MR pulmonary imaging framework, the authors show that simultaneous PET/MR, unique in its capability of combining structural information from MR with functional information from PET, shows promise in pulmonary imaging.

Comparison of metabolic and anatomic response to chemotherapy based on PERCIST and RECIST in patients with advanced stage non-small cell lung cancer

BACKGROUND

The aim of this study was to explore the prognostic role of metabolic response to chemotherapy, determined by FDG-PET, in patients with metastatic non-small-cell lung cancer (NSCLC).

MATERIALS AND METHODS

Thirty patients with metastatic NSCLC were analyzed for prognostic factors related to overall survival (OS) and progression free survival (PFS). Disease evaluation was conducted with FDG-PET/CT and contrast-enhanced CT prior to and at the end of first-line chemotherapy. Response evaluation of 19 of 30 patients was also performed after 2-3 cycles of chemotherapy. Morphological and metabolic responses were assessed according to RECIST and PERCIST, respectively.

RESULTS

The median OS and PFS were 11 months and 6.2 months, respectively. At the end of first-line chemotherapy, 10 patients achieved metabolic and anatomic responses. Of the 19 patients who had an interim response analysis after 2-3 cycles of chemotherapy, 3 achieved an anatomic response, while 9 achieved a metabolic response. In univariate analyses, favorable prognostic factors for OS were number of cycles of first-line chemotherapy, and achieving a response to chemotherapy at completion of therapy according to the PERCIST and RECIST. The OS of patients with a metabolic response after 2-3 cycles of chemotherapy was also significantly extended. Anatomic response at interim analysis did not predict OS, probably due to few patients with anatomic response. In multivariate analyses, metabolic response after completion of therapy was an independent prognostic factor for OS.

CONCLUSIONS

Metabolic response is at least as effective as anatomic response in predicting survival. Metabolic response may be an earlier predictive factor for treatment response and OS in NSCLC patients.

Feasibility of FDG-PET/CT for the initial diagnosis of papillary thyroid cancer

To assess the role of [18F]-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) as a preoperative diagnostic tool in papillary thyroid carcinoma (PTC). From 2011 to 2014, 197 patients with PTC (246 tumor foci in all) underwent FDG-PET. Among these patients, 46 underwent neck dissection for lateral neck metastasis. According to the FDG avidity of the tumor foci or lateral neck metastasis, factors associated with the prognostic value were evaluated by univariate and multivariate logistic regression analyses. Among the 197 patients, 7 (3.6 %) were incidentally found to have non-thyroid origin malignancy. Additionally, 63.0 % (155/246) of PTC foci showed FDG uptake on PET/CT. Univariate analysis showed that the tumor size, the presence of extrathyroidal extension, BRAF mutation, and Hashimoto thyroiditis were associated with FDG avidity. However, except for pathological extrathyroidal extension, the other factors showed statistically significant correlations with FDG avidity (p < 0.001, p = 0.008, and p = 0.009, respectively). FDG uptake in lateral neck node metastasis showed high specificity and negative predictive value (NPV). In four cases of nonspecific findings on ultrasonography (USG)/CT, FDG avidity was helpful to diagnose the presence of lateral neck metastasis. The maximum standardized uptake value (SUVmax) of PET/CT was correlated with the maximum diameter of the involved lateral node. FDG avidity did not show any significance in the recurrence-free survival of both the thyroid tumor and lateral neck metastasis. The FDG avidity of PTC did not show prognostic predictive meaning. However, in the case of lateral neck metastasis, FDG avidity showed high sensitivity and NPV, and could provide better information in cases of nonspecific findings on USG and CT.

(18)F-fluorodeoxyglucose positron-emission tomography-computed tomography to diagnose recurrent cancer

Background:

Sometimes the diagnosis of recurrent cancer in patients with a previous malignancy can be challenging. This prospective cohort study assessed the clinical utility of ¹⁸F-fluorodeoxyglucose positron-emission tomography-computed tomography (¹⁸F-FDG PET-CT) in the diagnosis of clinically suspected recurrence of cancer.

Methods:

Patients were eligible if cancer recurrence (non-small-cell lung (NSCL), breast, head and neck, ovarian, oesophageal, Hodgkin's or non-Hodgkin's lymphoma) was suspected clinically, and if conventional imaging was non-diagnostic. Clinicians were asked to indicate their management plan before and after ¹⁸F-FDG PET-CT scanning. The primary outcome was change in planned management after ¹⁸F-FDG PET-CT.

Results:

Between April 2009 and June 2011, 101 patients (age, median 65 years; 55% female) were enroled from four cancer centres in Ontario, Canada. Distribution by primary tumour type was: NSCL (55%), breast (19%), ovarian (10%), oesophageal (6%), lymphoma (6%), and head and neck (4%). Of the 99 subjects who underwent ¹⁸F-FDG PET-CT, planned management changed after ¹⁸F-FDG PET-CT in 52 subjects (53%, 95% confidence interval (CI), 42–63%); a major change in plan from no treatment to treatment was observed in 38 subjects (38%, 95% CI, 29–49%), and was typically associated with ¹⁸F-FDG PET-CT findings that were positive for recurrent cancer (37 subjects). After 3 months, the stated post-¹⁸F-FDG PET-CT management plan was actually completed in 88 subjects (89%, 95% CI, 81–94%).

Conclusion:

In patients with suspected cancer recurrence and conventional imaging that is non-diagnostic, ¹⁸F-FDG PET-CT often provides new information that leads to important changes in patient management.

Metabolic response assessment with 18F-FDG PET/CT: inter-method comparison and prognostic significance for patients with non-small cell lung cancer

OBJECTIVE

This study aimed to (1) compare the agreement of two evaluation methods of metabolic response in patients with non-small cell lung cancer (NSCLC) and determine their prognostic value and (2) explore an optimal cutoff of metabolic reduction to distinguish a more favorable subset of responders.

METHODS

This is a secondary analysis of prospective studies. Enrolled patients underwent 18F-PET/CT within 2 weeks before, during, and months after radiotherapy (post-RT). Metabolic response was assessed using both Peter MacCallum (PM) method of qualitative visual assessment and University of Michigan (UM) method of semiquantitative measurement. The agreement between two methods determined response, and their prediction of outcome was analyzed.

RESULTS

Forty-four patients with median follow-up of 25.2 months were analyzed. A moderate agreement was observed between PM- and UM-based response assessment (Kappa coefficient = 0.434), unveiling a significant difference in CMR rate (p = 0.001). Categorical responses derived from either method were significantly predictive of overall survival (OS) and progression-free survival (PFS) (p < 0.0001). Numerical percentage decrease of FDG uptake also showed significant correlations with survival, presenting a hazard ratio of 0.97 for both OS and PFS. A 75 % of SUV decrease was found to be the optimal cutoff to predict OS and 2-year progression.

CONCLUSIONS

There was a modest discrepancy in metabolic response rates between PM and UM criteria, though both could offer predictive classification for survival. The percentage decrease provides an ordinal value that correlates with prolonged survival, recommending 75 % as the optimal threshold at identifying better responders.

Risk factors for mediastinal lymph node metastasis in non-small-cell lung cancer by PET/CT

OBJECTIVE

The aim of this study was to investigate the relationship between mediastinal lymph node metastasis based on fluorine-18 fluorodeoxyglucose ((18)F-FDG) PET/computed tomography (PET/CT) of the primary tumor and various clinical indexes to determine the risk factors for malignant lymph nodes in non-small-cell lung cancer (NSCLC).

MATERIALS AND METHODS

A total of 130 patients with histologically proven NSCLC who had not received any therapy underwent (18)F-FDG PET/CT for staging. The relationship between node metastasis, sex, age, smoking status, primary tumor maximum standardized uptake value (SUV(max)), size, pathological type, and differentiation was studied by univariate analyses, and risk factors for nodal metastasis in NSCLC were assessed by multivariate logistic regression.

RESULTS

Of the 130 patients, 68 were seen to have nodal metastasis on histological analysis. Nodal metastasis was correlated with SUV(max), size, and differentiation of primary lung lesions (P<0.05), and all the other factors were nonsignificant (P>0.05). On multivariate logistic regression analysis, the only independent factor was SUV(max) of the primary tumor, and the optimal cutoff value was 9.3 (sensitivity: 75.41%, 95% confidence interval: 62.7-85.5; specificity: 54.41%, 95% confidence interval: 41.9-66.5).

CONCLUSION

The mediastinal lymph node metastasis ratio was correlated with SUV(max), size, and differentiation in primary lung lesions. SUV(max) was the only independent predictor of lymph node metastasis in NSCLC. Video Abstract: http://links.lww.com/NMC/A22.

PET/CT assessment of neuroendocrine tumors of the lung with special emphasis on bronchial carcinoids

Pulmonary neuroendocrine tumors (pNETs) arise from bronchial mucosal cells known as enterochromaffin cells which are part of the diffuse neuroendocrine system. The pathological spectrum of pNETs ranges from low-/intermediate-grade neoplasms such as bronchial carcinoids (BCs), also known as typical or atypical carcinoids, to high-grade neoplasms as large-cell neuroendocrine carcinoma and small-cell lung cancer. The tumor biology of pNETs still represents a matter of open debate. The distinct features among the different pNETs include not only their pathologic characteristics but also their clinical behavior, epidemiology, treatment, and prognosis. In this sense, a correct pathological identification in the preoperative setting is a key element for planning the best strategy of care in pNETs and especially in BCs. Controversial results have been reported on the diagnostic accuracy of fluorine-18-fluorodeoxyglucose positron emission tomography or positron emission tomography/computed tomography (F-18-FDG PET or PET/CT) in BCs. On the other hand, there is increasing evidence supporting the use of PET with somatostatin analogues (DOTA-TOC, DOTA-NOC, or DOTA-TATE) labeled with gallium-68 (Ga-68) in pNETs. Herein, we review the pertinent literature aiming to better define the current state of art of PET/CT in the detection and histological differentiation of pNETs with special emphasis on BCs.

Functional imaging evaluation in the detection, diagnosis, and histologic differentiation of pulmonary neuroendocrine tumors

Pulmonary neuroendocrine tumors (pNETs) have distinct pathologic characteristics. Typical carcinoids are indolent neoplasms with a good prognosis, whereas atypical carcinoids have a less indolent behavior. Both are optimally treated with complete surgical excision. More aggressive pNETs often present with local invasion, thoracic lymph nodal metastases, and distant spread. Patients may not be candidates for surgical resection and are treated with chemotherapy and/or radiation therapy. This article examines the potential role of functional imaging evaluation using (18)F FDG and somatostatin analogues labeled with (68)Ga DOTA-peptides in well-differentiated pNETs with particular attention to clinical and surgical implications.