Prognostic impact of standardized uptake value of F-18 FDG PET/CT in nasopharyngeal carcinoma

The role of 18 F-FDG PET/CT in detecting recurrence and metastasis in posttreatment nasopharyngeal carcinoma patients with elevated Epstein-Barr virus DNA

OBJECTIVE

The objective of this study is to evaluate and compare the clinical utility of 18 F-fluoro-2-deoxy-d-glucose PET and computed tomography ( 18 F-FDG PET/CT) in detecting recurrence and metastasis in patients with nasopharyngeal carcinoma (NPC) who exhibit elevated levels of Epstein-Barr virus (EBV) DNA following treatment.

METHODS

A total of 103 patients with NPC were studied retrospectively. All patients were in remission following initial treatment. Elevated EBV DNA was found for the first time at review and 18 F-FDG PET/CT imaging was completed. The number of tracer lesions and the maximum standardized uptake value in the body region were recorded to evaluate the diagnostic ability of 18 F-FDG PET/CT. The final diagnosis was confirmed either through pathology or clinical follow-up lasting 6 months or longer.

RESULTS

Out of the 103 patients, 97 patients had a total of 434 lesions that were ultimately diagnosed as recurrent or metastatic. In patient-based analyses, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 18 F-FDG PET/CT imaging were 100%, 50%, 97%, and 100%, respectively. In lesion-based analyses, the sensitivity, specificity, PPV, and NPV of 18 F-FDG PET/CT imaging were 99.3%, 30.3%, 94.9%, and 83.3%, respectively.

CONCLUSION

18 F-FDG PET/CT demonstrates potential value in detecting recurrence and metastasis of NPC.

Radiomics-clinical nomogram based on pretreatment 18F-FDG PET-CT radiomics features for individualized prediction of local failure in nasopharyngeal carcinoma

To explore the prognostic significance of PET/CT-based radiomics signatures and clinical features for local recurrence-free survival (LRFS) in nasopharyngeal carcinoma (NPC). We retrospectively reviewed 726 patients who underwent pretreatment PET/CT at our center. Least absolute shrinkage and selection operator (LASSO) regression and the Cox proportional hazards model were applied to construct Rad-score, which represented the radiomics features of PET-CT images. Univariate and multivariate analyses were used to establish a nomogram model. The concordance index (C-index) and calibration curve were used to evaluate the predictive accuracy and discriminative ability. Receiver operating characteristic analysis was performed to stratify the local recurrence risk of patients. The nomogram was validated by evaluating its discrimination ability and calibration in the validation cohort. A total of eight features were selected to construct Rad-score. A radiomics-clinical nomogram was built after the selection of univariate and multivariable Cox regression analyses, including the Rad-score and maximum standardized uptake value (SUVmax). The C-index was 0.71 (0.67-0.74) in the training cohort and 0.70 (0.64-0.76) in the validation cohort. The nomogram also performed far better than the 8th T-staging system with an area under the receiver operating characteristic curve (AUC) of 0.75 vs. 0.60 for 2 years and 0.71 vs. 0.60 for 3 years. The calibration curves show that the nomogram indicated accurate predictions. Decision curve analysis (DCA) revealed significantly better net benefits with this nomogram model. The log-rank test results revealed a distinct difference in prognosis between the two risk groups. The PET/CT-based radiomics nomogram showed good performance in predicting LRFS and showed potential to identify patients at high-risk of developing NPC.

Prognostic value of pre-treatment FDG PET/CT SUVmax for metastatic lesions in de novo metastatic nasopharyngeal carcinoma following chemotherapy and locoregional radiotherapy

BACKGROUND

To explore the prognostic role of FDG PET/CT maximal standard uptake values of metastatic lesions (SUVmax-M) in patients with de novo metastatic nasopharyngeal carcinoma (mNPC) following palliative chemotherapy and locoregional radiotherapy (LRRT).

METHODS

We retrospectively collected the information of 86 eligible patients between Jan 2012 and Oct 2020. All the parameters involving SUVmax and serum lactate dehydrogenase (LDH) at diagnosis were evaluated and cutoff values were determined by the maximum log-rank statistic method. The multivariate analysis was performed using Cox proportional hazards regression to identify the independent prognostic factors associated with overall survival (OS). All estimated survival rates were conducted with Kaplan-Meier method.

RESULTS

Median survival and progression time in the cohort were 38.2 and 13.9 months, respectively. The univariable analysis showed that male, number of metastatic sites ≥ 4, presence of liver, serum LDH ≥ 229, SUVmax-M ≥ 10, SUVmax-M-sum ≥ 10, and SUVmax-M-mean ≥ 8.8 were significant prognostic factors. Five variables were identified after LASSO regression and entered into the multivariate analysis. Furthermore, liver involvement (P = 0.039), elevated LDH (≥ 229) (P = 0.05) and higher SUVmax-M (≥ 10) (P = 0.004) were significantly associated with worse OS.

CONCLUSION

The high SUVmax of metastatic lesions (≥ 10), liver involvement, and elevated serum LDH (≥ 229) at diagnosis could independently predict poor survival for de novo mNPC patients treated with palliative chemotherapy following LRRT.

The valuable role of dynamic 18F FDG PET/CT-derived kinetic parameter Ki in patients with nasopharyngeal carcinoma prior to radiotherapy: A prospective study

BACKGROUND AND PURPOSE

Dynamic positron emission tomography/computed tomography (PET/CT) served the potential role of characterizing malignant foci. The main objective of this prospective study was to explore the advantage of dynamic PET/CT imaging in characterizing nasopharyngeal carcinoma (NPC).

METHODS AND MATERIALS

Patients with probable head and neck disease underwent a local dynamic PET/CT scan followed by a whole-body static scan. Patlak analysis was used to generate parametric influx rate constant (K_i) images from 48 frames obtained from a dynamic PET/CT scan. By delineating the volumes-of-interest (VOIs) of: primary tumor (PT), lymph node (LN), and normal nasopharyngeal tissues (N), we acquired the corresponding K_i mean and SUVmean of each site respectively to perform the quantitative statistical analysis.

RESULTS

Qualified images of 71 patients with newly diagnosed NPC and 8 without nasopharyngeal malignant lesions were finally included. We found the correlations between K_i mean-PT and critical clinical features, including clinical stage (r = 0.368), T category (r = 0.643) and EBV-DNA copy status (r = 0.351), and K_i mean-PT differed within the group. SUVmean-PT showed correlations with clinical stage (r = 0.280) and T category (r = 0.472), but could hardly differ systematically within group of clinical features except T category. K_i mean-LN offered the positive correlations with N category (r = 0.294), M category (r = 0.238) and EBV-DNA copy status (r = 0.446), and differed within the group. In addition, K_i mean represented a sensitivity of 94.4 % and a specificity of 100 %, in distinguishing NPC from the non-NPC, when the cut-off was defined as 0.0106. When the cut-off of SUV being defined as 2.03, the sensitivity and specificity were both 100 %.

CONCLUSION

Our research confirmed K_i compared favorably to SUV in characterizing NPC and found that K_i can serve as an effective imaging marker of NPC.

Reflecting on the utility of standardized uptake values on 18F-FDG PET in nasopharyngeal carcinoma

BACKGROUND

To rethink the clinical significance of standardized uptake values (SUVs) of nasopharyngeal carcinoma (NPC) on 18F-fluorodeoxyglucose (18F-FDG) positron-emission tomography (PET).

METHODS

We retrospectively reviewed 369 NPC patients who underwent pretreatment 18F-FDG PET. The predictive value of the SUVmax of the primary tumor (SUVmax-t) and regional lymph nodes (SUVmax-n) was evaluated using probability density functions. Receiver operating characteristic curves were used to determine optimal cutoffs for the SUVmax-n/SUVmax-t ratio (NTR). Kaplan-Meier and Cox regression analyses were used to assess survival.

RESULTS

The optimal SUVmax-t and SUVmax-n cutoffs were 7.5 and 6.9, respectively. High SUVmax-t and SUVmax-n were related to local and regional recurrence, respectively. Patients with low SUVmax had better 3-year overall survival (OS). To avoid cross-sensitization of cutoff points, we stratified patients with high SUVmax into the low and high NTR groups. The 3-year distant metastasis-free survival (DMFS; 92.3 vs. 80.6%, P = 0.009), progression-free survival (PFS; 84.0 vs. 67.7%, P = 0.011), and OS (95.9 vs. 89.2%, P = 0.002) significantly differed between the high vs. low NTR groups for patients with high SUVmax. Multivariable analysis showed that NTR was an independent prognostic factor for DMFS (hazard ratio [HR]: 2.037, 95% CI: 1.039-3.992, P = 0.038), PFS (HR: 1.636, 95% CI: 1.021-2.621, P = 0.041), and OS (HR: 2.543, 95% CI: 1.214-5.325, P = 0.013).

CONCLUSION

High SUVmax was associated with NPC recurrence. NTR is a potential prognosticator for DMFS, suggesting that heterogeneity in the pretreatment 18F-FDG uptake between the primary tumor and lymph nodes is associated with high invasion and metastatic potential.

Histogram analysis of 18F-FDG PET imaging SUVs may predict the histologic grade of oral squamous cell carcinoma

OBJECTIVE

We tested the hypothesis that histogram analysis parameters of standardized uptake values (SUVs) obtained preoperatively using ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) are significantly influenced by differences in metabolic capacity due to the histologic grade of oral squamous cell carcinoma (OSCC).

STUDY DESIGN

The study included 62 patients who were clinically diagnosed with OSCC and received surgical treatment after an ¹⁸F-FDG PET examination. Histogram analysis was performed using all voxels contained in the tumor area of each patient with an SUV ≥2.5. The histogram parameters calculated were the mean and standard deviation of SUVs, maximum SUV, metabolic tumor volume, skewness, and kurtosis. Statistical analyses were performed using a Mann-Whitney U test to calculate the significance of differences in these parameters between groups with well- and moderately- or poorly-differentiated tumors. Statistical significance was assumed at P < .05.

RESULTS

Only a comparison of kurtosis in the histogram showed a significant difference between the well- and moderately/poorly-differentiated tumors (P = .0294).

CONCLUSIONS

The distribution of metabolic capacity in oral squamous cell carcinoma tissues revealed on an ¹⁸F-FDG PET examination may help identify the histologic grade. This finding may provide valuable information for determining the subsequent treatment plan and predicting disease prognosis.

Circulating Plasma Epstein-Barr Virus DNA Load During the Follow-up Periods Predicts Recurrence and Metastasis in Nasopharyngeal Carcinoma

BACKGROUND

Epstein-Barr virus DNA (EBV DNA) load has been identified as a prognostic factor in nasopharyngeal carcinoma (NPC), whereas the dynamic changes in the long period have not been explored. In this study, we evaluated EBV DNA kinetics and its role in the survival.

METHODS

We conducted a retrospective review of 900 NPC patients. Plasma EBV DNA levels were measured at various time points after treatment. The correlations of EBV kinetics with recurrence and metastasis were analyzed. After stratifying patients according to the EBV results, survival was compared using Kaplan-Meier estimates. Twelve- and 24-month landmark analyses for overall survival (OS) data were performed according to the EBV groups.

RESULTS

Patients with post-EBV of less than 2500 copies/mL achieved better survival than did those with higher ones. Furthermore, patients with continuously elevated EBV DNA expressed significantly poorer OS (hazard ratio [HR], 2.542, 95% confidence interval [CI], 2.077-3.111; P < 0.001), distant metastasis-free survival (HR, 2.970; 95% CI, 2.392-3.687; P < 0.001), locoregional-free survival (HR, 1.699; 95% CI, 1.072-2.692; P = 0.013), and progression-free survival (HR, 2.535; 95% CI, 1.987-3.233; P < 0.001) than did patients with continuously normal EBV or those with elevated levels at any time point. The 5-year OS with elevated EBV was lower than that of the remission group by using the 12- and 24-month landmark analysis.

CONCLUSIONS

Elevated EBV DNA after treatment was a better predictive indicator of survival than the baseline concentrations. Furthermore, continuously elevated EBV DNA after treatment indicated recurrence, metastasis, and unfavorable prognosis for NPC. In addition, there were consistent patterns of EBV DNA kinetics during long-term follow-up, which warrant further study.

Prognostic significance of metabolic tumour volume and maximum standard uptake value of fluor-18-fluorodeoxyglucose positron emission tomography with computed tomography in nasopharyngeal carcinoma

Aim of the study

To evaluate the prognostic role of markers of fluor-18-fluorodeoxyglucose positron emission tomography with computed tomography (¹⁸F-FDG-PET-CT), such as maximum standard uptake value (SUV_max) and metabolic tumour volume (MTV) measured at primary and nodal disease, and their clinical significance in terms of predicting treatment outcomes and survival.

Material and methods

Between January 2017 and January 2020, 20 case records of nasopharyngeal carcinoma patients who underwent ¹⁸F-FDG-PET-CT as part of staging workup before radiotherapy and as a part of response evaluation after radiotherapy were retrospectively reviewed.

Results

At a median follow-up of 34.7 months, the 2-year progression-free survival (PFS) was 70% and 2-year overall survival (OS) was 79%. Patients with a lower nodal SUV_max (SUV_max-N) had a better 2-year PFS (91% vs. 46%; p = 0.035) and 2-year OS (95% vs. 58%; p = 0.015). A high SUV_max-N of > 10.58 was a negative predictor of OS (95% confidence interval [CI]: 0.93-1; p = 0.003) as well as PFS (95% CI: 0.64-1; p = 0.017). Also, a high MTV > 25.8 cm³ was a negative predictor of PFS (95% CI: 0.58-0.98; p = 0.048). MTV was an independent predictor of PFS and OS on univariate analysis, whereas it was not significant in the Cox regression multivariate analysis.

Conclusions

High values of MTV and SUV_max-N can be considered as independent prognostic factors of OS and PFS in nasopharyngeal cancer patients treated with concurrent chemoradiation, highlighting the need for more intensified treatment.

The Role of Pretreatment 18F-FDG PET/CT for Early Prediction of Neoadjuvant Chemotherapy Response in Patients with Locoregionally Advanced Nasopharyngeal Carcinoma

Introduction

To evaluate the role of maximal standardized uptake values (SUVmax) and total lesion glycolysis (TLG) from serial ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for early prediction of neoadjuvant chemotherapy (NAC) response in locoregionally advanced nasopharyngeal carcinoma (LANPC).

Methods

A total of 121 LANPC patients who completed pretreatment ¹⁸F-FDG PET/CT between June 2017 and July 2020 were retrospectively included. The median age of all the participants was 50 years old (range: 19–74 years), with 94 (77.7%) males and 27 (22.3%) females. The SUVmax from the primary tumor site (SUVmax-PT) and the total lesion glycolysis from the primary tumor site (TLG-PT) were recorded. Tumor response was calculated according to the Response Evaluation Criteria in Solid Tumor (RECIST) 1.1 Criteria at two-week post-secondary NAC cycle. Patients who achieved an objectively partial or full reaction after two cycles of NAC were defined as ‘responders’, and patients who obtained stability or progression were classified as ‘non-responders’.

Results

After two cycles of NAC, 96 patients were categorized as “responders” and 25 patients as “non-responders”. The optimal thresholds of the SUVmax-PT were 11.8 and 38.5 for the TLG-PT. Non-responders were significantly associated with high SUVmax-PT (HR, 3.49; 95% CI, 1.17–10.36; p = 0.024) and TLG-PT (HR, 4.45; 95% CI, 1.44–13.78; p = 0.010) in multivariate analysis. Recursive partitioning analysis (RPA) categorized patients into three prognostic groups based on SUVmax-PT and TLG-PT: high-response group, intermediate-response group, and low-response group, with corresponding favorable response rates of 94%, 80%, and 55%, respectively. Moreover, a nomogram was created based on metabolic parameters that precisely projected an individual’s response of NAC (C-index, 0.787; 95% CI, 0.533–1.000).

Conclusion

Pretreatment ¹⁸F-FDG PET/CT to measure SUVmax-PT and TLG-PT could be a useful non-invasive method for early indication of NAC efficacy. The nomogram based on PET/CT parameters may potentially provide direction for treatment decisions based on NAC levels.

Usefulness of [18F]fluorodeoxyglucose PET/CT for evaluating the PD-L1 status in nasopharyngeal carcinoma

PURPOSE

To explore the relationship between [¹⁸F]fluorodeoxyglucose (¹⁸F-FDG uptake) and PD-L1 expression and determine the usefulness of ¹⁸F-FDG PET/CT for evaluating the PD-L1 status in tumour cells (TCs) and tumour-infiltrating immune cells (TIICs) in patients with nasopharyngeal carcinoma (NPC).

METHODS

We retrospectively evaluated the records of 84 eligible patients who received an initial histopathological diagnosis of NPC between December 2016 and March 2019. All tissue specimens and PET/CT images were collected prior to treatment. High PD-L1 expression in TCs and TIICs was defined as ≥ 50% of stained cells.

RESULTS

There was a significant difference in ¹⁸F-FDG uptake according to the PD-L1 status in TCs and TIICs. Univariate analysis showed that PD-L1 expression in TCs was associated with tumour maximum standardized uptake value (SUVmax) (P < 0.001), primary tumour total lesion glycolysis (TLG; P < 0.001), and T stage (P = 0.044), but not with plasma Epstein-Barr virus (EBV) load (P = 0.816), whereas PD-L1 expression in TIICs was related to SUVmax (P = 0.011), TLG (P = 0.001), T stage (P = 0.028), and plasma EBV load (P = 0.003). In multivariate logistic regression, PD-L1 expression in TCs was positively associated with SUVmax (P = 0.003) and TLG (P = 0.001), and in TIICs, negatively associated with SUVmax (P = 0.038) and plasma EBV load (P = 0.025).

CONCLUSIONS

¹⁸F-FDG uptake in NPC lesions was positively correlated with PD-L1 expression in TCs and negatively correlated with PD-L1 expression in TIICs. Thus, ¹⁸F-FDG PET/CT may be useful for evaluating the PD-L1 status in patients with NPC.

Significant value of 18F-FDG-PET/CT in diagnosing small cervical lymph node metastases in patients with nasopharyngeal carcinoma treated with intensity-modulated radiotherapy

BACKGROUND

Little is known about the nature of metastasis to small cervical lymph nodes (SCLNs) in the patients with nasopharyngeal carcinoma (NPC) examined by using 18-fluoro-2-deoxy-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT). The present study aimed to evaluate the diagnostic values of PET/CT in identifying metastasis in SCLNs in NPC patients.

METHODS

Magnetic resonance images (MRI) and PET/CT scans for 470 patients with newly diagnosed, non-distant metastatic NPC were analyzed. Metastatic rates of SCLNs were defined by the positive number of SCLNs on PET/CT scans and total number of SCLNs on MRI scans. Receiver operating characteristic curve was applied to compare PET/CT-determined stage with MRI-determined stage.

RESULTS

In total, 2082 SCLNs were identified, with 808 (38.8%) ≥ 5 and < 6 mm in diameter (group A), 526 (25.3%) ≥ 6 and < 7 mm in diameter (group B), 374 (18.0%) ≥ 7 and < 8 mm in diameter (group C), 237 (11.4%) ≥ 8 and < 9 mm in diameter (group D), and 137 (6.5%) ≥ 9 and < 10 mm in diameter (group E). The overall metastatic rates examined by using PET/CT for groups A, B, C, D, and E were 3.5%, 8.0%, 31.3%, 60.0%, and 83.9%, respectively (P < 0.001). In level IV/Vb, the metastatic rate for nodes ≥ 8 mm was 84.6%. PET/CT examination resulted in modification of N category and overall stage for 135 (28.7%) and 46 (9.8%) patients, respectively. The areas under curve of MRI-determined and PET/CT-determined overall stage were 0.659 and 0.704 for predicting overall survival, 0.661 and 0.711 for predicting distant metastasis-free survival, and 0.636 and 0.663 for predicting disease-free survival.

CONCLUSIONS

PET/CT was more effective than MRI in identifying metastatic SCLNs, and the radiologic diagnostic criteria for metastatic lymph nodes in level IV/Vb should be re-defined.

Establishment of an integrated model incorporating standardised uptake value and N-classification for predicting metastasis in nasopharyngeal carcinoma

Background

Previous studies reported a correlation between the maximum standardised uptake value (SUV_max) obtained by ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) and distant metastasis in nasopharyngeal carcinoma (NPC). However, an integrated model incorporating SUV_max and anatomic staging for stratifying metastasis risk has not been reported.

Results

The median SUV_max for primary tumour (SUV-T) and cervical lymph nodes (SUV-N) was 13.6 (range, 2.2 to 39.3) and 8.4 (range, 2.6 to 40.9), respectively. SUV-T (HR, 3.396; 95% CI, 1.451-7.947; P = 0.005), SUV-N (HR, 2.688; 95%CI, 1.250-5.781; P = 0.011) and N-classification (HR, 2.570; 95%CI, 1.422-4.579; P = 0.001) were identified as independent predictors for DMFS from multivariate analysis. Three valid risk groups were derived by RPA: low risk (N0-1 + SUV-T <10.45), medium risk (N0-1 + SUV-T >10.45) and high risk (N2-3). The three risk groups contained 100 (22.3%), 226 (50.3%), and 123 (27.4%) patients, respectively, with corresponding 3-year DMFS rates of 99.0%, 91.5%, and 77.5% (P <0.001). Moreover, multivariate analysis confirmed the RPA-based prognostic grouping as the only significant prognostic indicator for DMFS (HR, 3.090; 95%CI, 1.975-4.835; P <0.001).

Methods

Data from 449 patients with with histologically-confirmed, stage I-IVB NPC treated with radiotherapy or chemoradiotherapy were retrospectively analysed. A prognostic model for distant metastasis-free survival (DMFS) was derived by recursive partitioning analysis (RPA) combining independent predictors identified by multivariate analysis.

Conclusion

SUV-T, SUV-N and N-classification were identified as independent predictors for DMFS. An integrated RPA-based prognostic model for DMFS incorporating SUV-N and N-classification was proposed.

Prognostic value of nodal SUVmax of 18F-FDG PET/CT in nasopharyngeal carcinoma treated with intensity-modulated radiotherapy

Purpose

To investigate the predictive role of maximum standardized uptake value (SUV_max) of 2-[¹⁸F]fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) in nasopharyngeal cancer patients treated with intensity-modulated radiotherapy (IMRT).

Materials and Methods

Between October 2006 and April 2016, 53 patients were treated with IMRT in two institutions and their PET/CT at the time of diagnosis was reviewed. The SUV_max of their nasopharyngeal lesions and metastatic lymph nodes (LN) was recorded. IMRT was delivered using helical tomotherapy. All patients except for one were treated with concurrent chemoradiation therapy (CCRT). Correlations between SUV_max and patients’ survival and recurrence were analyzed.

Results

At a median follow-up time of 31.5 months (range, 3.4 to 98.7 months), the 3-year overall survival (OS) and disease-free survival (DFS) rates were 83.2% and 77.5%, respectively. In univariate analysis, patients with a higher nodal pre-treatment SUV_max (≥ 13.4) demonstrated significantly lower 3-year OS (93.1% vs. 55.5%; p = 0.003), DFS (92.7% vs. 38.5%; p < 0.001), locoregional recurrence-free survival (100% vs. 50.5%; p < 0.001), and distant metastasis-free survival (100% vs. 69.2%; p = 0.004), respectively. In multivariate analysis, high pre-treatment nodal SUV_max (≥ 13.4) was a negative prognostic factor for OS (hazard ratio [HR], 7.799; 95% confidence interval [CI], 1.506–40.397; p = 0.014) and DFS (HR, 9.392; 95% CI, 1.989–44.339; p = 0.005).

conclusions

High pre-treatment nodal SUV_max was an independent prognosticator of survival and disease progression in nasopharyngeal carcinoma patients treated with IMRT in our cohort. Therefore, nodal SUV_max may provide important information for identifying patients who require more aggressive treatment.

Cervical nodal volume for prognostication and risk stratification of patients with nasopharyngeal carcinoma, and implications on the TNM-staging system

We aim to evaluate the quantitative parameters of ¹⁸F-FDG PET/CT (metabolic parameters) and MRI (morphologic parameters) for prognostication and risk stratification in nasopharyngeal carcinoma (NPC). 200 (147 males, aged 50 ± 13 years-old, mean ± S.D.) newly diagnosed patients with NPC (T_xN_xM₀) were prospectively recruited. Primary tumor and nodal lesions were identified and segmented for both morphologic (volume, VOL) and metabolic (SUV and MTV) quantification. Independent predictive factors for recurrence free survival (RFS) and overall survival (OS) were morphologic nodal volume (VOL_N, p < 0.001), TNM-stage (p = 0.022), N-Stage (p = 0.024) for RFS, and VOL_N (p = 0.014) for OS. Using Classification and Regression Tree (CART) analysis, three risk-layers were identified for RFS: Stage I/II with VOL_N < 18cc (HR = 1), stage III /IV with VOL_N < 18cc (HR = 2.93), VOL_N ≥ 18cc (HR = 7.84) regardless of disease stage (p < 0.001). For OS, two risk layers were identified: VOL_N < 18cc (HR = 1), VOL_N ≥ 18cc (HR = 4.23) (p = 0.001). The 18cc threshold for morphologic nodal volume was validated by an independent cohort (n = 105). Based on the above risk-classification, 35 patients (17.5%) would have a higher risk than suggested by the TNM-staging system. Thus, morphologic nodal volume is an important factor in prognostication and risk stratification in NPC, and should be incorporated into the staging system, while PET parameters have no advantage for this purpose in our cohort.

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.

Prognostic value of primary gross tumor volume and standardized uptake value of 18F-FDG in PET/CT for distant metastasis in locoregionally advanced nasopharyngeal carcinoma

Distant metastasis has become the predominant model of treatment failures in patients with locoregionally advanced nasopharyngeal carcinoma. Effort should therefore be made to stratify locoregionally advanced nasopharyngeal carcinoma patients into different groups based on the risk of metastasis to improve prognosis and tailor individualized treatments. This study aims to assess the value of primary gross tumor volume and the maximum standardized uptake value for predicting distant metastasis-free survival of patients with locoregionally advanced nasopharyngeal carcinoma. A total of 294 locoregionally advanced nasopharyngeal carcinoma patients who were identified from prospectively maintained database and underwent fluor-18-fluorodeoxyglucose positron emission tomography/computed tomography imaging before treatment were included. The maximum standardized uptake value was recorded for the primary tumor (SUVmax-P) and neck lymph nodes (SUVmax-N). Computed tomography-derived primary gross tumor volume was measured using the summation-of-area technique. At 5 years, the distant metastasis-free survival rate was 83.7%. The cut-off of the SUVmax-P, SUVmax-N, and primary gross tumor volume for distant metastasis-free survival was 8.95, 5.75, and 31.3 mL, respectively, by receiver operating characteristic curve. In univariate analysis, only SUVmax-N (hazard ratio: 7.01; 95% confidence interval: 1.70-28.87; p < 0.01) and clinical stage (hazard ratio: 3.03; 95% confidence interval: 1.67-5.47; p = 0.007) were confirmed as independent predictors of distant metastasis-free survival. A prognostic model was derived by SUVmax-N and clinical stage: low risk (SUVmax-N < 5.75 regardless of clinical stage), medium risk (stage III and SUVmax-N ≥ 5.75), and high risk (stage IV and SUVmax-N ≥ 5.75). Multivariate analysis revealed that SUVmax-N and the prognostic model remained independent prognostic factors for distant metastasis-free survival (p = 0.023 and p < 0.001, respectively), but the clinical stage became insignificant (p = 0.133). Furthermore, the adjusted hazard ratios for the prognostic model were higher than SUVmax-N (hazard ratio = 6.27 vs 5.21, respectively). In summary, compared with SUVmax-P, SUVmax-N may be a better predictor of distant metastasis-free survival for patients with locoregionally advanced nasopharyngeal carcinoma. Combining SUVmax-N with clinical stage gives a more precise picture in predicting distant metastasis.

Prognostic value of 18F-FDG-PET/CT in patients with nasopharyngeal carcinoma: a systematic review and meta-analysis

BACKGROUND

The prognostic role of 18F-fluorodeoxyglucose positron emission tomography CT (18F-FDG PET/CT) parameters is still controversial in nasopharyngeal carcinoma patients. We sought to perform a systematic review and meta-analysis to explore the prognostic value of maximal standardized uptake value (SUVmax), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) on event-free survival (EFS) and overall survival (OS) in nasopharyngeal carcinoma patients.

RESULTS

Fifteen studies comprising 1,938 patients were included in this study. The combined hazard ratios (HRs) for EFS were 2.63 (95%CI 1.71-4.05) for SUVmax, 2.55 (95%CI 1.49-4.35) for MTV, and 3.32 (95%CI 1.23-8.95) for TLG. The pooled HRs for OS were 2.07 (95%CI 1.54-2.79) for SUVmax, 3.86 (95%CI 1.85-8.06) for MTV, and 2.60 (95%CI 1.55-4.34) for TLG. The prognostic role of SUVmax, MTV and TLG remained similar in the sub-group analyses.

METHODS

A systematic literature search was performed to identify studies which associated 18F-FDG PET/CT to clinical survival outcomes of nasopharyngeal carcinoma patients. The summarized HRs for EFS and OS were estimated by using fixed- or random-effect models according to heterogeneity between trials.

CONCLUSIONS

The present meta-analysis confirms that high values of SUVmax, MTV and TLG predicted a higher risk of adverse events or death in patients with nasopharyngeal carcinoma, despite clinically heterogeneous nasopharyngeal carcinoma patients and the various methods adopted between these studies.

Prognostic value of pretreatment 18F-FDG PET-CT for nasopharyngeal carcinoma patients

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a special subtype of head and neck cancer (HNC). At present, there are no highly specific prognostic markers to aid in tumor grading and guide patient treatment modalities for NPC. The prognostic value of pretreatment F-fluorodeoxyglucose positron emission tomography-computed tomography (F-PET-CT) in NPC patients is controversial and no consensus exists as to its predictive capability.

METHODS

To analyze the predictive efficacy of F-PET-CT imaging in NPC patients, data from MEDLINE, EMBASE, the Cochrane library, CBM, CNKI, and VIP (inception to July 2016) were accessed. Results from prospective and retrospective observational studies that used F-FDG PET to predict disease prognosis in NPC patients were used for analysis. Two authors independently assessed study quality and extracted data. Event-free survival (EFS) was considered the primary endpoint and overall survival rate (OS) was considered the secondary endpoint.

RESULTS

Data from 14 studies and 1134 patients were included in our analysis. The hazard ratios (HRs) of maximum standardized uptake value of primary tumor (SUVmax-T), metabolic tumor volume of primary tumor (MTV-T), and total lesional glycolysis of primary tumor (TLG-T) for EFS were 1.31 (95% confidence interval [CI], 1.11-1.55, P = .001), 2.38 (95% CI 1.53-3.70, P < .001), and 1.65 (95% CI 0.76-3.59, P = .21), respectively. Among studies including TLG-T, those with a fixed SUV of 2.5 had an HR of 3.55 (95% CI, 1.42-8.84, P = .007). The HRs of SUVmax-T and MTV-T for OS were 2.19 (95% CI, 1.47-3.27, P < .001) and 2.69 (95% CI, 1.01-7.17, P = .05), respectively. Among studies including MTV-T, those with a fixed SUV of 2.5 had an HR of 4.07 (95% CI, 2.22-7.46, P < .001). Tests used for assessing predictive value of pretreatment SUVmax, MTV, and TLG of lymph nodes for EFS and OS showed that these parameters did not have significant predictive value (P>.05).

CONCLUSION

Our results suggested that SUVmax, MTV, and TLG (with a fixed SUV of 2.5) of primary tumors before treatment initiation may be independent prognostic factors for NPC patients; however, SUVmax, MTV, and TLG of metastatic lymph nodes are not.

Lymph node standardized uptake values at pre-treatment 18F-fluorodeoxyglucose positron emission tomography as a valuable prognostic factor for distant metastasis in nasopharyngeal carcinoma

Objective:

The aim of the present study was to evaluate prognostic values of pre-treatment fluorine-18 fludeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) parameters for predicting the distant metastasis (DM) of nasopharyngeal cancer.

Methods:

73 patients diagnosed with nasopharyngeal cancer with regional lymph node (LN) involvement, who underwent pre-treatment ¹⁸F-FDG PET evaluation between January 2005 and December 2012, were retrospectively reviewed. We assessed the ¹⁸F-FDG PET parameters of the primary tumours (T–) and regional LNs (N–). For patients with bilateral retropharyngeal, bilateral neck and/or supraclavicular LN involvement, we also assessed the ¹⁸F-FDG PET parameters of the farthest LN station [N(f)–]. The following ¹⁸F-FDG PET parameters were evaluated: maximum standardized uptake value (SUV_max), mean standardized uptake value (SUV_mean), peak standardized uptake value (SUV_peak), metabolic tumour volumes (MTVs) (MTV₃₀–MTV₇₀, which were calculated as the tumour volume with 30%, 40%, 50%, 60% and 70% of the SUV_max as the threshold, respectively) and total lesion glycolysis (TLG) (TLG₃₀–TLG₇₀, which were determined by the product of each MTV and the corresponding SUV_mean within that MTV). Distant metastasis-free survival (DMFS) rates were estimated from the date of the start of radiotherapy to the date of DM or last follow-up by the Kaplan–Meier method. Univariate and multivariate analyses were performed to identify prognostic factors for DMFS. The median follow-up period was 53 months (range 12–110 months).

Results:

Most patients (95%) received concurrent chemoradiotherapy. The major failure pattern was DM (15 of all patients, 21%) and the 5-year DMFS was 79%. In univariate analysis, the T–SUV_max, T–SUV_mean, T–SUV_peak, N–SUV_max, N–SUV_peak, N(f)–SUV_max and N(f)–SUV_peak were significant prognostic factors for DMFS. In multivariate analysis, the T–SUV_max, T–SUV_peak, N(f)–SUV_max and N(f)–SUV_peak were significant prognostic factors for DMFS. Of these parameters, the N(f)–SUV_max (hazard ratio = 6.524; p = 0.001) and N(f)–SUV_peak (hazard ratio = 5.399; p = 0.001) were the strongest prognostic factors for DMFS.

Conclusion:

In patients with nasopharyngeal cancer with LN involvement, the standardized uptake value parameter of the farthest LN station seems to be an important ¹⁸F-FDG PET parameter for predicting DM. Further studies are needed to validate its clinical significance.

Advances in knowledge:

We found that pre-treatment ¹⁸F-FDG PET parameters of primary tumours and regional LNs (the SUV_max and SUV_peak of the primary tumour and the farthest LN station) were significant prognostic factors for DMFS in patients with nasopharyngeal carcinoma with LN involvement.

Prognostic Value of (18)F-FDG PET-CT in Nasopharyngeal Carcinoma: Is Dynamic Scanning Helpful?

OBJECTIVES

To evaluate the differences in prognostic values of static and dynamic PET-CT in nasopharyngeal carcinoma (NPC).

MATERIAL AND METHODS

Forty-five patients who had static scan were recruited. Sixteen had dynamic scan. The primary lesions were delineated from standardized uptake value (SUV) maps from static scan and K i maps from dynamic scan. The average follow-up lasted for 34 months. The patients who died or those with recurrence/residual disease were considered "poor outcome"; otherwise they were considered "good outcome." Fisher's exact test and ROC analysis were used to evaluate the prognostic value of various factors.

RESULTS

Tumor volume thresholded by 40% of maximal SUV (VOLSUV40) significantly predicted treatment outcome (p = 0.024) in the whole cohort. In 16 patients with dynamic scan, all parameters by dynamic scan were insignificant in predicting the outcome. The combination of maximal SUV, maximal K i , VOLSUV40, and VOL K i 37 (the tumor volume thresholded by 37% maximal K i ) achieved the highest predicting accuracy for treatment outcome with sensitivity, specificity, and accuracy of 100% in these 16 patients; however this improvement compared to VOLSUV40 was insignificant.

CONCLUSION

Tumor volume from static scan is useful in NPC prognosis. However, the role of dynamic scanning was not justified in this small cohort.

Positron emission tomography-computed tomography before treatment is highly prognostic of distant metastasis in nasopharyngeal carcinoma patients after intensity-modulated radiotherapy treatment: a prospective study with long-term follow-up

OBJECTIVES

The utility of [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) in the prediction of distant metastasis after definitive treatment for non-disseminated NPC patients is not clear. We prospectively investigated the prognostic significance of (18)F-FDG PET-CT performed before treatment for the distant metastasis-free survival (DMFS) of NPC patients treated with intensity-modulated radiotherapy (IMRT) ± chemotherapy.

MATERIALS AND METHODS

The results of PET-CT scans performed at initial diagnosis were recorded and analyzed prospectively. Patients then received standard treatment per protocol independent of the PET-CT result. IMRT was administered to the nasopharynx and neck. Early stage patients received IMRT alone, whereas loco-regionally advanced patients received concurrent chemoradiation. Patient outcomes were evaluated.

RESULTS

One hundred and seventy-nine patients were analyzable. DM occurred in 33 patients and the 3-year DMFS rate of the whole cohort was 84.1%. The cut-off of the SUVmax at the primary site (SUVmax-P) for DMFS was 10.22 by ROC curve. The 3-year DMFS rates of the higher and lower SUVmax-P groups (SUVmax-P⩽or>10.22) were 93.2% and 75.1%, respectively, with an 18.1% difference (P=0.003). Multivariate analysis indicated that SUVmax-P was a risk factor independently associated with DMFS (HR, 2.672; 95%CI, 1.236-5.776; P=0.012) and OS (HR, 2.417; 95%CI, 1.313-4.448; P=0.005). Subgroup analysis indicated that the 5-year DMFS and OS in loco-regionally advanced patients with SUVmax-P⩽10.22 were similar to those of early stage patients, whereas those of loco-regionally advanced patients with SUVmax-P>10.22 patients predicted worse outcome.

CONCLUSION

SUVmax-P is a useful biomarker to predict distant metastasis of NPC patients treated with IMRT. Combining SUVmax-P with tumor overall stage, a more precise picture could be obtained to predict treatment outcome.

Effective inhibition of nasopharyngeal carcinoma in vitro and in vivo by targeting glycolysis with oxamate

Elevated aerobic glycolysis in cancer cells (Warburg effect) has been observed in many tumor types including nasopharyngeal carcinoma (NPC), which can often be detected clinically using FDG-PET. However, the role of glycolysis in supporting the growth of NPC cells and its therapeutic implications still remain to be investigated. In the present study, we showed that the LDH inhibitor oxamate significantly suppressed NPC cell proliferation in vitro and tumor growth in vivo, yet exhibited minimum toxicity to normal nasopharyngeal epithelial cells in vitro and was well tolerated in mice. Moreover, oxamate exhibited cytotoxic effect in NPC cells under hypoxia. Mechanistic study showed that oxamate significantly inhibited LDH activity, leading to a substantial decrease in glucose uptake and lactate production. Combination of oxamate with a mitochondrial respiratory complex I inhibitor resulted in a significant depletion of cellular ATP and a synergistic killing of cancer cells. Our results suggest that inhibition of glycolysis by oxamate is an effective therapeutic strategy for treatment of NPC and that combination of this compound with mitochondrial-targeted agents may improve the therapeutic activity.

Nasopharyngeal carcinoma: investigation of intratumoral heterogeneity with FDG PET/CT

OBJECTIVE

The purpose of this study was to quantitatively evaluate the role of intratumoral heterogeneity of (18)F-FDG uptake in characterizing nasopharyngeal carcinoma (NPC).

SUBJECTS AND METHODS

Forty consecutively registered patients with newly diagnosed NPC underwent PET/CT. The heterogeneity factor, defined as the derivative of a volume threshold function, was computed for each tumor. The relations between heterogeneity factor and maximum standardized uptake value (SUV(max)), tumor volume, and TNM category were determined by two-tailed Spearman correlation. Factors that potentially affect outcome determined by disease-free survival were studied by Kaplan-Meier analysis with a log-rank test for univariate analysis and the Cox proportional hazard model for multivariate analysis.

RESULTS

The heterogeneity factor ranged from -1.80 to -0.13 (mean, -0.40 [SD, 0.40]) and significantly correlated with SUV(max) (r = -0.372; p = 0.018), tumor volume (r = -0.983; p < 0.001), and T category (r = -0.457; p = 0.003) but not with N and M categories. There was a significant difference in heterogeneity factor between T1 and T2 tumors and T3 and T4 tumors (p = 0.012). The 2-year disease-free survival rate among the 38 patients was 67.4%. According to the results of Kaplan-Meier analysis with the log-rank test, heterogeneity factor and M category significantly affected disease-free survival. Patients with tumors that had a heterogeneity factor greater than -0.24 (less-heterogeneous group) (p = 0.0498) or M0 status (p < 0.001) had better disease-free survival rates. Multivariate analysis showed only M category to be an independent predictor of disease-free survival (p < 0.001).

CONCLUSION

The intratumoral heterogeneity of FDG uptake varies across NPC tumors, significantly correlates with tumor aggressiveness, and is predictive of patient outcome. These findings may be useful for characterizing NPC, predicting survival, and improving patient care.