Whole-body 18F-FDG PET/CT for M staging in the patient with newly diagnosed nasopharyngeal carcinoma: Who needs?

Individualized radiology screening for newly diagnosed nasopharyngeal carcinoma

OBJECTIVES

Current guidelines recommend universal PET/CT screening for metastases staging in newly diagnosed nasopharyngeal carcinoma (NPC) despite the low rate of synchronous distant metastasis (SDM). The study aims to achieve individualized screening recommendations of NPC based on the risk of SDM.

METHODS AND MATERIALS

18 pre-treatment peripheral blood indicators was retrospectively collected from 2271 primary NPC patients. A peripheral blood risk score (PBRS) was constructed by indicators associated with SDM on least absolute shrinkage and selection operator (LASSO) regression. The PBRS-based distant metastases (PBDM) model was developed from features selected by logistic regression analyses in the training cohort and then validated in the validation cohort. Receiver operator characteristic curve analysis, calibration curves, and decision curve analysis were applied to evaluate PBDM model performance.

RESULTS

Pre-treatment Epstein-Barr viral DNA copy number, percentage of total lymphocytes, serum lactate dehydrogenase level, and monocyte-to-lymphocyte ratio were most strongly associated with SDM in NPC and used to construct the PBRS. Sex (male), T stage (T3-4), N stage (N2-3), and PBRS (≥1.076) were identified as independent risk factors for SDM and applied in the PBDM model, which showed good performance. Through the model, patients in the training cohort were stratified into low-, medium-, and high-risk groups. Individualized screening recommendations were then developed for patients with differing risk levels.

CONCLUSION

The PBDM model offers individualized recommendations for applying PET/CT for metastases staging in NPC, allowing more targeted screening of patients with greater risk of SDM compared with current recommendations.

A diagnosis model in nasopharyngeal carcinoma based on PET/MRI radiomics and semiquantitative parameters

BACKGROUND

The staging of nasopharyngeal carcinoma (NPC) is of great value in treatment and prognosis. We explored whether a positron emission tomography/ magnetic resonance imaging (PET/MRI) based comprehensive model of radiomics features and semiquantitative parameters was useful for clinical evaluation of NPC staging.

MATERIALS AND METHODS

A total of 100 NPC patients diagnosed with non-keratinized undifferentiated carcinoma were divided into early-stage group (I-II) and advanced-stage group (III-IV) and divided into the training set (n = 70) and the testing set (n = 30). Radiomics features (n = 396 × 2) of the primary site of NPC were extracted from MRI and PET images, respectively. Three major semiquantitative parameters of primary sites including maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) in all NPC patients were measured. After feature selection, three diagnostic models including the radiomics model, the metabolic parameter model, and the combined model were established using logistic regression model. Finally, internal validation was performed, and a nomogram for NPC comprehensive diagnosis has been made.

RESULTS

The radiomics model and metabolic parameter model showed an area under the curve (AUC) of 0.83 and 0.80 in the testing set, respectively. The combined model based on radiomics and semiquantitative parameters showed an AUC of 0.90 in the testing set, with the best performance among the three models.

CONCLUSION

The combined model based on PET/MRI radiomics and semiquantitative parameters is of great value in the evaluation of clinical stage (early-stage group and advanced-stage group) of NPC.

Expression of fibroblast activation protein in lung cancer and its correlation with tumor glucose metabolism and histopathology

PURPOSE

To explore the expression of fibroblast activation protein (FAP) in lung cancer (LC) and its correlation with tumor glucose metabolism and histopathology.

METHODS

From June 2018 to November 2020, 73 patients with newly diagnosed LC were included. Immunohistochemical staining was used to quantify FAP expression in tumors. The histopathological type and tumor grade were determined via histopathological examination. The tumor glucose metabolism parameters and tumor maximal diameter were measured via [¹⁸F] F-FDG PET/CT. Univariate and multivariate analysis were performed to study the correlation of FAP expression levels with glucose metabolism variables and tumor histopathology.

RESULTS

Positive FAP expression was observed in 97.3% (71/73) LC lesions, which was significantly higher than 87.7% (64/73) of [¹⁸F] F-FDG positivity observed on PET/CT (χ² = 4.818, P = 0.028). In 12 early adenocarcinomas (ADCs), only three lesions (25%) were positive for [¹⁸F] F-FDG on PET/CT; however, 10 lesions (83.3%) were positive for FAP. When FAP expression was classified into low level (scores ≤ 3) and high level (scores > 4), high FAP level was found in 80.8% tumors and low FAP level in the other 19.2% tumors. High FAP level was identified in 100.0% of squamous cell carcinomas (SCCs), 85.7% of ADCs, 66.7% (4/6) of large cell neuroendocrine carcinomas (LCNCs), and 40.0% (4/10) of small cell lung cancers (SCLCs) (P < 0.05). In non-mucinous ADC lesions, on univariate analysis, FAP expression level showed a close relationship with tumor metabolism parameters (maximal standard uptake value (SUVmax), mean standard uptake value (SUVmean), and total lesion glycolysis (TLG)), tumor diameter, tumor grade, and lesion attenuation (P < 0.05).

CONCLUSION

The present study demonstrates that FAP is widely expressed in LC and shows great variation in different histopathological types. A high positive rate of FAP expression implies that FAP-targeted imaging may be a sensitive modality for diagnosing LC, especially in early ADCs. Further validation with such probes is warranted.

Selectively recommend 18F-FDG PET/CT for patients with de novo nasopharyngeal carcinoma in endemic areas

INTRODUCTION

To identify the subset of patients with de novo nasopharyngeal carcinoma (NPC) for whom [¹⁸F] fluorodeoxyglucose positron emission tomography and computed tomography (¹⁸F-FDG PET/CT) should be recommended, and to determine whether PET/CT is a cost-effective decision for precise M staging in endemic areas.

MATERIALS AND METHODS

Retrospective analysis of data of 4469 patients diagnosed with de novo NPC between January 2014 and December 2019. The detection rate of distant metastasis was compared between different groups. Univariate and multiple logistic regression analysis was applied to identify the risk factors for distant metastasis. The cost-effectiveness of the diagnostic strategies was assessed.

RESULTS

The detection rate of distant metastasis in the whole cohort was 5.46%. In multivariate analysis, male sex, T3-4 stage, N2-3 stage, and high plasma Epstein-Barr virus (EBV) DNA (≥ 14,650 copies/mL) were risk factors for distant metastases. NPC patients with T3-4 stage combined with N2-3 stage, high EBV DNA combined with male sex, or N2-3 stage combined with high EBV DNA were defined as recommended group with relatively higher tendency for metastasis. Distant metastasis incidence in recommended group and unrecommended group were 10.25% and 1.75%, respectively (P < 0.001). In the recommended group, PET/CT significantly improved the detection rate of distant metastasis (13.25% vs 9.02%, P = 0.005). Cost-effectiveness analysis revealed that additional cost for every one percent increase in distant metastasis detection rate was $22,785.58 in the recommended group (< Willingness-to-pay (WTP) threshold of $32,700.00) and $310,912.90 in the unrecommended group.

CONCLUSIONS

In patients with de novo NPC, the tendency for metastasis can be predicted based on clinical parameters. ¹⁸F-FDG PET/CT should be selectively recommended for the subset of patients with a relatively higher tendency for metastasis.

Prognostic Relevance of 18F-FDG-PET/CT-Guided Target Volume Delineation in Loco-Regionally Advanced Nasopharyngeal Carcinomas: A Comparative Study

Introduction

An optimal approach to define tumor volume in locoregionally advanced nasopharyngeal carcinoma (NPC) using 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) remains unclear. This retrospective study aimed at comparing the outcomes and toxicities of different FDG-PET/CT-guided techniques for primary tumor volume delineation in locoregionally advanced NPC.

Methods

From August 2015 to February 2018, 292 patients with stage III-IVB NPC received FDG-PET/CT-guided IMRT. Three PET/CT-based techniques were used to determine the gross tumor volume (GTV) as follows: visual criteria (group A; n = 98), a standard uptake value (SUV) threshold of 2.5 (group B; n = 95), and a threshold of 50% maximal intensity (group C, n = 99) combined with a dose-painting technique.

Results

In groups A, B, and C, the 5-year LRFS rates were 89.4%, 90.0%, and 97.8%, respectively (p = 0.043). The 5-year DMFS rates were 75.1%, 76.0%, and 87.7%, respectively (p = 0.043). The 5-year DFS rates were 70.9%, 70.3%, and 82.2%, respectively (p = 0.048). The 5-year OS rates were 73.5%, 73.9%, and 84.9%, respectively (p = 0.038). Group C showed significantly higher 5-year LRFS, LRRFS, DMFS, DFS, and OS than those in groups A and B (p < 0.05). No statistically significant differences were observed between the three study groups in the cumulative incidences of grade 3-4 acute and late toxicities. Multivariate analyses showed that the PET/CT-guided technique for target volume delineation was an independent prognostic factor for 5-year LRFS, DFS, DMFS, and OS (p = 0.039, p = 0.030, p = 0.035 and p = 0.028, respectively), and was marginally significant in predicting LRRFS (p = 0.080).

Conclusions

The 50% SUVmax threshold regimen for GTV delineation with dose-painting appeared to be superior to the visual criteria or SUV2.5 threshold in locoregionally advanced NPC, and there was no increased toxicity.

Nomogram for the prediction of primary distant metastasis of nasopharyngeal carcinoma to guide individualized application of FDG PET/CT

PURPOSE

This study aimed to establish an effective nomogram to predict primary distant metastasis (DM) in patients with nasopharyngeal carcinoma (NPC) to guide the application of PET/CT.

METHODS

In total, 3591 patients with pathologically confirmed NPC were consecutively enrolled. The nomogram was constructed based on 1922 patients treated between 2007 and 2014. Multivariate logistical regression was applied to identify the independent risk factors of DM. The predictive value of the nomogram was evaluated using the concordance index (C-index), calibration curve, probability density functions (PDFs), and clinical utility curve (CUC). The results were validated in 1669 patients enrolled from 2015 to 2016. Net reclassification improvement (NRI) was applied to compare performances of the nomogram with other clinical factors. The best cut-off value of the nomogram chosen for clinical application was analyzed.

RESULTS

A total of 355 patients showed primary DM among 3591 patients, yielding an incidence rate of 9.9%. Sex, N stage, EBV DNA level, lactate dehydrogenase level, and hemoglobin level were independent predictive factors for primary DM. C-indices in the training and validation cohort were 0.796 (95% CI, 0.76-0.83) and 0.779 (95% CI, 0.74-0.81), respectively. The NRI indices demonstrated that this model had better predictive performance than plasma EBV DNA level and N stage. We advocate for a threshold probability of 3.5% for guiding the application of PET/CT depending on the clinical utility analyses.

CONCLUSION

This nomogram is a useful tool to predict primary DM of NPC and guide the clinical application of PET/CT individually at the initial staging.

Distant metastases and synchronous malignancies on FDG-PET/CT in patients with head and neck cancer: a retrospective study

Background

Fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) has been proven to be a good method to detect distant spread of head and neck cancer (HNC). However, most prior studies are based on Asian populations and may not be directly transferable to western populations.

Purpose

To investigate the frequency and distribution of distant metastases and synchronous malignancies detected by PET/CT in HNC in a northern Swedish population.

Material and Methods

All primary whole-body FDG-PET/CT examinations performed on the suspicion of HNC (n = 524 patients) between 1 January 2013 and 31 December 2016 at Umeå University Hospital in Sweden were retrospectively reviewed . After the exclusion of 189 examinations without evidence of primary HNC, 335 examinations were analyzed.

Results

Distant metastases were detected in 10 (3%) patients, all with advanced primary tumors corresponding to TNM stage 3–4, most frequently in salivary gland adenocarcinoma, where 50% of patients had distant spread. Four patients had metastases below the diaphragm, representing 20% of the salivary gland malignancies. In the remaining six patients, metastases were supraphrenic, of which all but one were identified by CT alone. Synchronous malignancies were discovered in 14 (4.2%) patients, of which five were below the diaphragm.

Conclusion

The overall frequency of distant spread and synchronous malignancy in primary HNC was generally low. However, the risk for distant metastases below the diaphragm was relatively higher in salivary gland adenocarcinoma, supporting whole-body FDG-PET/CT in the primary diagnostic work-up in these patients.

Current management of stage IV nasopharyngeal carcinoma without distant metastasis

Up to one in four patients with nasopharyngeal carcinoma present with non-metastatic stage IV disease (i.e. T4 or N3). Distinct failure patterns exist, despite the routine adoption of contemporary treatment modalities such as intensity modulated radiotherapy and systemic chemotherapy. Concurrent chemoradiotherapy (CCRT) followed by adjuvant chemotherapy or induction chemotherapy followed by CCRT are commonly employed in this setting, with the latter emerging as the preferred option. Additionally, emerging radiation technologies like proton therapy has become available offering new opportunities for prevention of radiation-induced side effects. This article reviews not only the current treatment strategies, but also discusses novel ways to tackle this challenging disease with respect to the patterns of failure.

Establishment and validation of a nomogram with intratumoral heterogeneity derived from 18F-FDG PET/CT for predicting individual conditional risk of 5-year recurrence before initial treatment of nasopharyngeal carcinoma

Background

Intratumoral heterogeneity has an enormous effect on patient treatment and outcome. The purpose of the current study was to establish and validate a nomogram with intratumoral heterogeneity derived from ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for prognosis of 5-Year progression-free survival (PFS) of patients with nasopharyngeal carcinoma (NPC).

Methods

A total of 171 NPC patients who underwent pretreatment ¹⁸F-FDG PET/CT were retrospectively enrolled. Data was randomly divided into training cohort (n = 101) and validation cohort (n = 70). The clinicopathologic parameters and the following PET parameters were analyzed: maximum and mean standardized uptake value (SUVmax, SUVmean), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and heterogeneity index (HI, SUVmax/SUVmean) for primary tumor and maximal neck lymph node. Cox analyses were performed on PFS in the training cohort. A prognostic nomogram based on this model was developed and validated.

Results

For the primary tumor, MTV-2.5, TLG-2.5, MTV-70%, and TLG-70% were significantly correlated with PFS. For the maximal neck lymph node, short diameter and HI were significantly correlated with PFS. Among the clinicopathologic parameters, M stage was a significant prognostic factor for recurrence. In multivariate analysis, M stage (P = 0.006), TLG-T-70% (P = 0.002), and HI-N (P = 0.018) were independent predictors. Based on this prognostic model, a nomogram was generated. The C-index of this model was 0.74 (95% CI: 0.63–0.85). For the cross validation, the C-index for the model was 0.73 (95% CI: 0.62–0.83) with the validation cohort. Patients with a risk score of ≥111 had poorer survival outcomes than those with a risk score of 0–76 and 77–110.

Conclusions

Intratumoral heterogeneity derived from ¹⁸F-FDG PET/CT could predict long-term outcome in patients with primary NPC. A combination of PET parameters and the TNM stage enables better stratification of patients into subgroups with different PFS rates.

18F-FDG PET/CT imaging findings in anaplastic large cell lymphoma, a rare subtype of lymphoma

OBJECTIVE

To investigate the 18F-FDG PET/CT imaging manifestations for anaplastic large cell lymphoma (ALCL), a rare subtype of T/NK cell lymphoma.

METHODS

Fifty patients with ALCL, including 32 anaplastic lymphoma kinase (ALK)-positive patients and 18 ALK-negative patients, were enrolled. The positive detection, maximal standardized uptake value (SUVmax), and distribution of nodal and extranodal involvement were recorded and analysed. Fifty patients with diffuse large B cell lymphoma (DLBCL) were collected as a control group.

RESULTS

ALCL lesions were demonstrated to be 18F-FDG-avid tumours with a mean SUVmax of 19.4 ± 12.6. Most (76%) ALCL patients presented with stage III-IV disease, and nodal and extranodal involvement occurred in 74.0 and 72.0% of the patients, respectively. ALCL and DLBCL showed many similarities in tumour stage, 18F-FDG uptake and tumour involvement (P > 0.05), although the preferred extranodal organs of involvement (bone and the gastrointestinal tract, respectively) were different (P < 0.05). Compared to ALK-negative lesions, a higher uptake of 18F-FDG was found in the ALK-positive lesions (SUVmax: 22.1 ± 14.3 vs. 15.1 ± 6.6, t = 2.354, P = 0.023). ALK-positive ALCL was more likely to involve the lymph nodes than ALK-negative ALCL (84.3% vs. 55.5%, χ2 = 4.973, P = 0.043), while ALK-negative ALCL was more prone to involve the extranodal organs compared to ALK-positive ALCL (88.9% vs. 62.5%, χ2 = 3.979, P = 0.046).

CONCLUSION

The present study demonstrated that ALCL is a systemic 18F-FDG-avid lymphoma with many imaging manifestations similar to DLBCL on PET/CT. The present study also showed that ALK expression actually influenced tumour 18F-FDG uptake and lesion distribution. These findings may be useful to improve the understanding of the biological characteristics of ALCL.

Detection of Distant Metastases in Head and Neck Cancer: Changing Landscape

As head and neck squamous cell carcinoma (HNSCC) patients with distant metastases (DM) were generally treated only palliatively, the value of screening for DM was usually limited to attempts to avoid extensive locoregional treatment when DM were present pretreatment. Recently, the concept of treating oligometastases, e.g., by metastatectomy or stereotactic body radiotherapy, has been reintroduced for HNSCC and may cause a change in the treatment paradigm. Although whole body ¹⁸F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) combined with computed tomography (CT; WB-FDG-PET/CT) is still the mainstay diagnostic technique, there is a growing body of evidence supporting implementation of whole body magnetic resonance imaging (WB-MRI) as an important diagnostic technique for screening for DM. Also, FDG-PET/MRI may become a valuable technique for the detection of DM in HNSCC patients. Because the yield of examinations for detection of DM is too low to warrant routine screening of all HNSCC patients, only patients with high risk factors should be selected for intense screening for DM. Clinical and histopathological risk factors are mainly related to the extent of lymph node metastases. Risk for development of DM may also be assessed by molecular characterization of the primary tumor using genomic and proteomic technologies and radiomics. More research is needed to develop a new protocol for screening for DM after introduction of the concept of treating oligometastases in HNSCC.

Low glucose metabolism in hepatocellular carcinoma with GPC3 expression

AIM

To investigate the relationship between glucose metabolism and glypican-3 (GPC3) expression in hepatocellular carcinoma (HCC).

METHODS

Immunohistochemical staining of pathological samples for GPC3 and glucose transporter 1 (GLUT1), and whole-body ¹⁸F-FDG PET/CT for measuring tumour glucose uptake were performed in 55 newly diagnosed HCC patients. The maximum standard uptake value (SUV_max) and tumour-to-non-tumourous liver uptake (T/NT) ratio were used to quantify ¹⁸F-FDG uptake. In vitro¹⁸F-FDG uptake assay of GPC3-expressing HepG2 and non-GPC3-expressing RH7777 cells was used to examine the effect of GPC3 in cellular glucose metabolism. The relationships between GPC3 expression and ¹⁸F-FDG uptake, GLUT1 expression, tumour differentiation, and other clinical indicators were analysed using Spearman rank correlation, univariate and multiple logistic regression analyses.

RESULTS

Positive GPC3 expression was observed in 67.3% of HCC patients, including 75.0% of those with well or moderately differentiated HCC and 36.4% of those with poorly differentiated HCC. There was an inverse relationship between GPC3 expression and SUV_max (Spearman correlation coefficient = -0.281, P = 0.038) and a positive relationship between GLUT1 expression and SUV_max (Spearman correlation coefficient = 0.681, P < 0.001) in patients with HCC. Univariate analysis showed that two glucose metabolic parameters (SUV_max and T/NT ratio), tumour differentiation, lymph node metastasis, and TNM stage were all significantly associated with GPC3 expression (P < 0.05), whereas GLUT1 expression, sex, age, tumour size, intrahepatic lesion number, and distant metastasis showed no statistical association (P > 0.05). Further multivariate analysis revealed that only the T/N ratio was significantly correlated with GPC3 expression in patients with HCC (P < 0.05). In vitro assay revealed that the uptake of ¹⁸F-FDG in GPC3-expressing HepG2 cells was significantly lower than that of non-GPC3-expressing RH7777 cells (t = -20.352, P < 0.001).

CONCLUSION

The present study demonstrated that GPC3 expression is inversely associated with glucose metabolism, suggesting that GPC3 may play a role in regulating glucose metabolism in HCC.

Prognostic value of 18F-fluorodeoxyglucose PET parameters and inflammation in patients with nasopharyngeal carcinoma

The aim of the present study was to investigate the association between positron emission tomography (PET) parameters and peripheral inflammatory markers, and assess their prognostic value in nasopharyngeal carcinoma (NPC). A total of 121 patients with non-disseminated NPC were recruited. Pretreatment maximum standardized uptake values (SUVmax) of PET and peripheral inflammatory factors (leukocyte, neutrophil and monocyte counts) were recorded. Kaplan-Meier and multivariate analyses were used to identify predictors for progression-free survival (PFS), overall survival (OS), distant metastasis-free survival (DMFS) and locoregional recurrence-free survival (LRFS). The results of the present study revealed that SUVmax at the primary tumor was positively correlated with leukocytes (P=0.025), neutrophils (P=0.009) and monocytes (P=0.043). SUVmax at regional lymph nodes (SUVmax-N) was significantly associated with monocytes (P=0.024). Kaplan-Meier analysis demonstrated that SUVmax-N (>10.15) significantly predicted PFS (P=0.004) and DMFS (P=0.003). In addition, neutrophils (>5.18) were significantly associated with PFS (P=0.001), DMFS (P=0.013) and LRFS (P<0.001). Multivariate analysis revealed that SUVmax-N and neutrophils retained independent prognostic significance for PFS (SUVmax-N, P=0.026; and neutrophils, P=0.033) and DMFS (SUVmax-N, P=0.026; and neutrophils, P=0.032). Furthermore, patients with SUVmax-N ≤10.15 and neutrophils ≤5.18 had significantly improved prognosis in PFS (96.4 vs. 58.5%, P<0.001), OS (95.7 vs. 81.1%, P=0.044), DMFS (96.4 vs. 67.0%, P<0.001) and LRFS (100 vs. 90.2%, P=0.036) compared with those with SUVmax-N >10.15 or neutrophils >5.18. In conclusion, SUVmax may be significantly associated with cancer-associated inflammation. SUVmax-N and neutrophils were independent prognostic indicators for PFS and DMFS. Combined assessment of SUVmax-N and neutrophils may lead to refinement of risk stratification in NPC.