Staging of untreated nasopharyngeal carcinoma with PET/CT: comparison with conventional imaging work-up. Eur J Nucl Med Mol Imaging. 2009;36:12-22. [PMID: 18704401 DOI: 10.1007/s00259-008-0918-7]

Comparison of [18F]FDG and [68 Ga]pentixafor PET/CT in Nasopharyngeal Carcinoma

PURPOSE

This study aimed to explore the feasibility of [68 Ga]pentixafor positron emission tomography/computed tomography (PET/CT) in patients with nasopharyngeal carcinoma (NPC).

PROCEDURES

This prospective study included patients with NPC who underwent [68 Ga]pentixafor PET/CT and 2-[18F]fuoro-2-deoxy-D-glucose ([18F]FDG) PET/CT within one week between November 2022 and March 2023. The [68 Ga]pentixafor and [18F]FDG uptakes in primary and metastatic lesions were measured and compared.

RESULTS

Twenty-five participants (21 patients for initial stage and four patients for recurrence detection) were enrolled in our study. The participants underwent [18F]FDG PET/CT and [68 Ga]pentixafor PET/CT. [68 Ga]pentixafor PET/CT had the same detection rate as [18F]FDG for primary tumor (96% vs. 96%). The [68 Ga]pentixafor maximum standard uptake value (SUVmax) and target-to-background ratio (TBR) of primary tumors were lower than those of [18F]FDG (SUVmax: 8.13 ± 2.78 vs. 14.25 ± 6.45; P < 0.01; TBR: 5.17 ± 2.14 vs. 9.81 ± 5.30, P < 0.01). The difference between tumor volume of [68 Ga]pentixafor (TVpentixafor) and tumor volume of [18F]FDG (TVFDG) showed no significance (median: 16.01 vs. 9.56, P = 0.332). In the detection of suspected metastatic cervical lymph nodes (CLNs), [68 Ga]pentixafor PET possessed a lower SUVmax than [18F]FDG PET/CT (SUVmax: 6.86 ± 2.63 vs. 10.39 ± 5.28, P < 0.01), but there was no significant difference in the detection rate between [68 Ga]pentixafor and [18F]FDG PET/CT (96 vs. 98, P = 0.613).

CONCLUSIONS

[68 Ga]pentixafor is a promising imaging tracer for detecting primary and metastatic NPC. [68 Ga]pentixafor PET/CT is comparable to [18F]FDG PET/CT in the detection rate of primary tumors and metastatic cervical lymph nodes in nasopharyngeal carcinoma, but [68 Ga]pentixafor uptake was heterogeneous. [68 Ga]pentixafor PET/CT may help select patients most likely to benefit from CXCR4-directed endoradiotherapy.

CLINICAL TRIAL REGISTRATION NO

ChiCTR2200065902.

Prognostic value of lymph node-to-primary tumor ratio of PET standardized uptake value for nasopharyngeal carcinoma: a recursive partitioning risk stratification analysis

Background

Induction chemotherapy (IC) combined with concurrent chemoradiotherapy has become the standard treatment for locoregionally advanced nasopharyngeal carcinoma (LA-NPC). Data on the prognostic value of the lymph node-to-primary tumor ratio (NTR) of positron emission tomography (PET) standardized uptake value (SUV) for patients treated with IC were limited.

Objectives

To evaluate the prognostic value of the SUV NTR for patients with LA-NPC treated with IC.

Design

In all, 467 patients with pretreatment 18F-fluorodeoxyglucose PET/computed tomography (CT) scans between September 2017 and November 2020 were retrospectively reviewed.

Methods

The receiver operating characteristic (ROC) analysis was used to determine the optimal cut-off value of SUV NTR. Kaplan-Meier method was used to evaluate survival rates. The recursive partitioning analysis (RPA) was performed to construct a risk stratification model.

Results

The optimal cutoff value of SUV NTR was 0.74. Multivariate analyses showed that SUV NTR and overall stage were independent predictors for distant metastasis-free survival (DMFS) and regional recurrent-free survival (RRFS). Therefore, an RPA model based on the endpoint of DMFS was generated and categorized the patients into three distinct risk groups: RPA I (low risk: SUV NTR < 0.74 and stage III), RPA II (medium risk: SUV NTR < 0.74 and stage IVa, or SUV NTR ⩾ 0.74 and stage III), and RPA III (high risk: SUV NTR ⩾ 0.74 and stage IVa), with a 3-year DMFS of 98.9%, 93.4%, and 84.2%, respectively. ROC analysis showed that the RPA model had superior predictive efficacy than the SUV NTR or overall stage alone.

Conclusion

SUV NTR was an independent prognosticator for distant metastasis and regional recurrence in locoregionally advanced NPC. The RPA risk stratification model based on SUV NTR provides improved DMFS and RRFS prediction over the eighth edition of the TNM (Tumor Node Metastasis) staging system.

ACR Appropriateness Criteria® Staging and Post-Therapy Assessment of Head and Neck Cancer

Imaging of head and neck cancer at initial staging and as part of post-treatment surveillance is a key component of patient care as it guides treatment strategy and aids determination of prognosis. Head and neck cancer includes a heterogenous group of malignancies encompassing several anatomic sites and histologies, with squamous cell carcinoma the most common. Together this comprises the seventh most common cancer worldwide. At initial staging comprehensive imaging delineating the anatomic extent of the primary site, while also assessing the nodal involvement of the neck is necessary. The treatment of head and neck cancer often includes a combination of surgery, radiation, and chemotherapy. Post-treatment imaging is tailored for the evaluation of treatment response and early detection of local, locoregional, and distant recurrent tumor. Cross-sectional imaging with CT or MRI is recommended for the detailed anatomic delineation of the primary site. PET/CT provides complementary metabolic information and can map systemic involvement. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Head and neck MRI-based T stage and [18F]FDG PET/CT-based N/M stage improved prognostic stratification in primary nasopharyngeal carcinoma

OBJECTIVES

To evaluate whether MRI-based T stage (TMRI), [18F]FDG PET/CT-based N (NPET/CT), and M stage (MPET/CT) are superior in NPC patients' prognostic stratification based on long-term survival evidences, and whether TNM staging method involving TMRI + NPET/CT + MPET/CT could improve NPC patients' prognostic stratification.

METHODS

From April 2007 to December 2013, 1013 consecutive untreated NPC patients with complete imaging data were enrolled. All patients' initial stages were repeated based on (1) the NCCN guideline recommended "TMRI + NMRI + MPET/CT" ("MMP") staging method; (2) the traditional "TMRI + NMRI + Mconventional work-up (CWU)" ("MMC") staging method; (3) the single-step "TPET/CT + NPET/CT + MPET/CT" ("PPP") staging method; or (4) the "TMRI + NPET/CT + MPET/CT" ("MPP") staging method recommended in present research. Survival curve, ROC curve, and net reclassification improvement (NRI) analysis were used to evaluate the prognosis predicting ability of different staging methods.

RESULTS

[18F]FDG PET/CT performed worse on T stage (NRI =  - 0.174, p < 0.001) but better on N (NRI = 0.135, p = 0.004) and M stage (NRI = 0.126, p = 0.001). The patients whose N stage upgraded by [18F]FDG PET/CT had worse survival (p = 0.011). The "TMRI + NPET/CT + MPET/CT" ("MPP") method performed better on survival prediction when compared with "MMP" (NRI = 0.079, p = 0.007), "MMC" (NRI = 0.190, p < 0.001), or "PPP" method (NRI = 0.107, p < 0.001). The "TMRI + NPET/CT + MPET/CT" ("MPP") method could reclassify patients' TNM stage to a more appropriate stage. The improvement is significant in patients with more than 2.5-years follow-up according to the time-dependent NRI values.

CONCLUSIONS

The MRI is superior to [18F]FDG PET/CT in T stage, and [18F]FDG PET/CT is superior to CWU in N/M stage. The "TMRI + NPET/CT + MPET/CT" ("MPP") staging method could significantly improve NPC patients' long-term prognostic stratification.

CLINICAL RELEVANCE STATEMENT

The present research provided long-term follow-up evidence for benefits of MRI and [18F]FDG PET/CT in TNM staging for nasopharyngeal carcinoma, and proposes a new imaging procedure for TNM staging incorporating MRI-based T stage and [18F]FDG PET/CT-based N and M stage, which significantly improves long-term prognostic stratification for patients with NPC.

KEY POINTS

• The long-term follow-up evidence of a large-scale cohort was provided to evaluate the advantages of MRI, [18F]FDG PET/CT, and CWU in the TNM staging of nasopharyngeal carcinoma. • A new imaging procedure for TNM stage of nasopharyngeal carcinoma was proposed.

Evaluation of 11 C-Choline PET/CT for T Staging and Tumor Volume Delineation in Nasopharyngeal Cancer Patients in Comparison to 18 F-FDG PET/CT

PURPOSE

Accurate determination of the primary tumor extension of nasopharyngeal carcinoma (NPC) by 18 F-FDG PET/CT is limited by the high physiological 18 F-FDG uptake in the surrounding area, especially in the brain tissue. We aimed to assess whether 11 C-choline PET/CT could improve the accuracy of T staging and tumor volume delineation for NPC patients.

METHODS

Patients with pathologically confirmed diagnosis of NPC were enrolled. The primary tumor extension of each patient was evaluated by 11 C-choline PET/CT, 18 F-FDG PET/CT, and contrast-enhanced MRI. The PET/CT-based tumor volume ( VPET ) was measured by 3 threshold methods, including the threshold of SUV 2.5 (Th 2.5 ), 40% of maximal SUV (Th 40% ), and the relative background-dependent threshold (Th bgd ). Tumor volume and Dice similarity coefficient were compared among VPET with different segmentation methods and VMR .

RESULTS

Thirty-three patients with treatment-naive NPC and 6 patients with suspicious recurrent disease were enrolled. The NPC lesions were avid for both 11 C-choline and 18 F-FDG. Visual analysis showed that 11 C-choline PET/CT had better contrast and higher discernability than 18 F-FDG PET/CT for intracranial, skull base, and orbital involvement. 11 C-choline PET/CT also exhibited advantage over MRI for differentiation between local recurrence and radiation-induced alterations. For the tumor delineated, the VMR was larger than VPET in general, except for 18 F-FDG PET/CT with Th 2.5 threshold. For all 3 threshold methods applied, 11 C-choline PET/CT produced more consistent and comparable tumor volume to MRI than 18 F-FDG PET/CT. 11 C-choline PET/CT with Th bgd threshold showed the closest tumor volume and highest similarity to MRI.

CONCLUSIONS

11 C-choline PET/CT provides a higher accuracy than 18 F-FDG PET/CT in mapping tumor extension in locally advanced NPC and may be a promising complement to MRI in delineating the primary tumor.

Automatic tumor segmentation and metachronous single-organ metastasis prediction of nasopharyngeal carcinoma patients based on multi-sequence magnetic resonance imaging

Background

Distant metastases is the main failure mode of nasopharyngeal carcinoma. However, early prediction of distant metastases in NPC is extremely challenging. Deep learning has made great progress in recent years. Relying on the rich data features of radiomics and the advantages of deep learning in image representation and intelligent learning, this study intends to explore and construct the metachronous single-organ metastases (MSOM) based on multimodal magnetic resonance imaging.

Patients and methods

The magnetic resonance imaging data of 186 patients with nasopharyngeal carcinoma before treatment were collected, and the gross tumor volume (GTV) and metastatic lymph nodes (GTVln) prior to treatment were defined on T1WI, T2WI, and CE-T1WI. After image normalization, the deep learning platform Python (version 3.9.12) was used in Ubuntu 20.04.1 LTS to construct automatic tumor detection and the MSOM prediction model.

Results

There were 85 of 186 patients who had MSOM (including 32 liver metastases, 25 lung metastases, and 28 bone metastases). The median time to MSOM was 13 months after treatment (7–36 months). The patients were randomly assigned to the training set (N = 140) and validation set (N = 46). By comparison, we found that the overall performance of the automatic tumor detection model based on CE-T1WI was the best (6). The performance of automatic detection for primary tumor (GTV) and lymph node gross tumor volume (GTVln) based on the CE-T1WI model was better than that of models based on T1WI and T2WI (AP@0.5 is 59.6 and 55.6). The prediction model based on CE-T1WI for MSOM prediction achieved the best overall performance, and it obtained the largest AUC value (AUC = 0.733) in the validation set. The precision, recall, precision, and AUC of the prediction model based on CE-T1WI are 0.727, 0.533, 0.730, and 0.733 (95% CI 0.557–0.909), respectively. When clinical data were added to the deep learning prediction model, a better performance of the model could be obtained; the AUC of the integrated model based on T2WI, T1WI, and CE-T1WI were 0.719, 0.738, and 0.775, respectively. By comparing the 3-year survival of high-risk and low-risk patients based on the fusion model, we found that the 3-year DMFS of low and high MSOM risk patients were 95% and 11.4%, respectively (p &lt; 0.001).

Conclusion

The intelligent prediction model based on magnetic resonance imaging alone or combined with clinical data achieves excellent performance in automatic tumor detection and MSOM prediction for NPC patients and is worthy of clinical application.

PET/CT standardized uptake value and EGFR expression predicts treatment failure in nasopharyngeal carcinoma

OBJECTIVE

This study inventively combines epidermal growth factor receptor (EGFR) expression of the primary lesion and standardized uptake value (SUV) of positron emission tomography and computed tomography (PET/CT) to predict the prognosis of nasopharyngeal carcinoma (NPC). This study aimed to evaluate the predictive efficacy of maximum standard uptake value (SUVmax) and EGFR for treatment failure in patients with NPC.

METHODS

This retrospective study reviewed the results of EGFR expression and pretreatment ¹⁸F-FDG PET/CT of 313 patients with NPC. Time-dependent receiver operator characteristics was used for analyzing results and selecting the optimal cutoff values. Cox regression was used to screen out multiple risk factors. Cumulative survival rate was calculated by Kaplan-Meier.

RESULTS

The selected cutoff value of SUVmax-T was 8.5. The patients were categorized into four groups according to EGFR expression and SUVmax-T. There were significant differences in the 3-year local recurrence-free survival (LRFS) (p = 0.0083), locoregional relapse-free survival (LRRFS) (p = 0.0077), distant metastasis-free survival (DMFS) (p = 0.013), and progression-free survival (PFS) (p = 0.0018) among the four groups. Patients in the EGFR-positive and SUVmax-T > 8.5 group had the worst survival, while patients in the EGFR-negative and SUVmax-T ≤ 8.5 group had the best prognosis. Subsequently, patients with only positive EGFR expression or high SUVmax-T were classified as the middle-risk group. There were also a significant difference in 3-year overall survival among the three risk groups (p = 0.034). SUVmax-T was associated with regional recurrence-free survival and LRRFS in multivariate analysis, whereas EGFR was an independent prognostic factor for LRRFS, DMFS, and PFS.

CONCLUSION

The combination of SUVmax-T and EGFR expression can refine prognosis and indicate clinical therapy.

Medial retropharyngeal nodal region sparing radiotherapy versus standard radiotherapy in patients with nasopharyngeal carcinoma: open label, non-inferiority, multicentre, randomised, phase 3 trial

OBJECTIVES

To address whether sparing the medial retropharyngeal lymph node (MRLN) region from elective irradiation volume provides non-inferior local relapse-free survival versus standard radiotherapy in patients with nasopharyngeal carcinoma.

DESIGN

Open-label, non-inferiority, multicentre, randomised, phase 3 trial.

SETTING

Three Chinese hospitals between 20 November 2017 and 3 December 2018.

PARTICIPANTS

Adults (18-65 years) with newly diagnosed, non-keratinising, non-distant metastatic nasopharyngeal carcinoma without MRLN involvement.

INTERVENTIONS

Randomisation was done centrally by the Clinical Trials Centre at Sun Yat-sen University Cancer Center. Eligible patients were randomly assigned (1:1; block size of four) to receive MRLN sparing radiotherapy or standard radiotherapy (both medial and lateral retropharyngeal lymph node groups), and stratified by institution and treatment modality as follows: radiotherapy alone; concurrent chemoradiotherapy; induction chemotherapy plus radiotherapy or concurrent chemoradiotherapy.

MAIN OUTCOME MEASURES

Non-inferiority was met if the lower limit of the one sided 97.5% confidence interval of the absolute difference in three year local relapse-free survival (MRLN sparing radiotherapy minus standard radiotherapy) was greater than -8%.

RESULTS

568 patients were recruited: 285 in the MRLN sparing radiotherapy group; 283 in the standard radiotherapy group. Median follow-up was 42 months (interquartile range 39-45), intention-to-treat analysis showed that the three year local relapse-free survival of the MRLN sparing radiotherapy group was non-inferior to that of the standard radiotherapy group (95.3% v 95.5%, stratified hazard ratio 1.04 (95% confidence interval 0.51 to 2.12), P=0.95) with a difference of -0.2% ((one sided 97.5% confidence interval -3.6 to ∞), P_{non-inferiority}<0.001). In the safety set (n=564), the sparing group had a lower incidence of grade ≥1 acute dysphagia (25.5% v 35.1%, P=0.01) and late dysphagia (24.0% v 34.3%, P=0.008). Patient reported outcomes at three years after MRLN sparing radiotherapy were better in multiple domains after adjusting for the baseline values: global health status (mean difference -5.6 (95% confidence interval -9.1 to -2.0), P=0.002), role functioning (-5.5 (-7.4 to -3.6), P<0.001), social functioning (-6.2 (-8.9 to -3.6), P<0.001), fatigue (7.9 (4.0 to 11.8), P<0.001), and swallowing (11.0 (8.4 to 13.6), P<0.001). The difference in swallowing scores reached clinical significance (>10 points difference).

CONCLUSION

Compared with standard radiotherapy, MRLN sparing radiotherapy showed non-inferiority in terms of risk of local relapse with fewer radiation related toxicity and improved patient reported outcomes in patients with non-metastatic nasopharyngeal carcinoma.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03346109.

Metastatic patterns of level II-V cervical lymph nodes assessed per vertebral levels in nasopharyngeal carcinoma

BACKGROUND AND PURPOSE

The current cervical lymph nodes classification system is not perfectly reasonable for radiotherapy of nasopharyngeal carcinoma (NPC). This study aimed to determine the metastatic patterns of level II-V lymph nodes in NPC by using vertebrae as anatomical landmarks.

MATERIALS AND METHODS

Four hundred and forty node-positive NPC patients were selected. Metastatic lymph nodes were diagnosed using positron emission tomography/computed tomography scan or magnetic resonance imaging. We evaluated univariate and multivariate logistic correlations between the vertebral levels of metastatic level II-V lymph nodes.

RESULTS

The metastasis rate of level II-V lymph nodes gradually decreased from C2 (66.5%) and C3 (68.2%) to T1 (4.1%) vertebral levels. When assessed per vertebral level, 98.4% were non-skip metastasis. The interval of vertebral levels and distance between the inferior border of the tumor and the metastatic lymph nodes were similar in N1 and N2 patients. Univariate correlation analysis showed the metastasis of level II-V lymph nodes at each vertebral level was associated with the metastasis at any other vertebral level. In the multivariate analysis, metastasis at any one of the C2-C7 vertebral levels strongly and positively correlated with metastasis at two adjacent vertebral levels, including one level above and one below.

CONCLUSION

This is the first study to report the distribution and non-skip metastatic patterns of level II-V lymph nodes assessed per vertebral levels in NPC. The low-risk clinical target volume could be reduced to two vertebral levels below the vertebral level of the metastatic level II-V nodes when both imaging modalities are available.

Survival effect of pretreatment FDG-PET-CT on nasopharyngeal cancer

BACKGROUND/PURPOSE

Accurate staging is the first step for optimal treatment selection in patients with nasopharyngeal carcinoma (NPC). In this propensity-score-matched, population-based cohort study, we investigated the survival effects of pretreatment 8-fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸FDG-PET-CT) on patients with NPC.

METHODS

We included patients with stage I-IVA NPC receiving radiotherapy or concurrent chemoradiotherapy and categorized them into two 1:1 propensity score-matched groups according to whether or not they underwent pretreatment ¹⁸FDG-PET-CT and compared their outcomes.

RESULTS

Of the 10,756 patients, propensity score matching yielded 4366 patients in each group. According to multivariable Cox regression analyses, the most prominent correlation between pretreatment ¹⁸FDG-PET-CT and all-cause death was observed in patients with stage II NPC (adjusted hazard ratio [aHR], 0.77; 95% confidence interval [CI], 0.60-0.90; P = .0433), followed by patients with stage III NPC (aHR, 0.81; 95% CI, 0.69-0.94; P = .0071) and patients with stage IVA NPC (aHR, 0.88; 95% CI, 0.79-0.97; P = .0091). This association was not significant in patients with stage I NPC (aHR, 1.20; 95% CI, 0.75-1.93; P = .4426).

CONCLUSION

Pretreatment ¹⁸FDG-PET-CT is associated with longer survival in patients with clinical stage II-IVA NPC but not in stage I NPC.

Prospective comparison of 68Ga-FAPI-04 and 18F-FDG PET/CT for tumor staging in nasopharyngeal carcinoma

Purpose

To explore the difference in the effectiveness of gallium-68 fibroblast activation protein inhibitor (⁶⁸Ga-FAPI-04) PET/CT and fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) PET/CT for the initial staging of patients with nasopharyngeal carcinoma (NPC).

Methods

The Affiliated Hospital of Southwest Medical University hosted this single-center prospective investigation (Clinical Trials registration No.ChiCTR2100044131) between March 2020 and September 2021. Within a week, all subjects underwent MR scans, ⁶⁸Ga-FAPI-04 PET/CT, and ¹⁸F-FDG PET/CT in order. The effectiveness of medical staging employing ⁶⁸Ga-FAPI-04 and ¹⁸F-FDG PET/CT was compared.

Results

Twenty-eight patients with primary NPC were evaluated (mean age53 ± 11 years). ⁶⁸Ga-FAPI-04 PET/CT indicated an elevated recognition rate for diagnosing primary tumors (28/28 [100%] vs. 27/28 [96%]) and lymph node metastases (263/285 [92%] vs. 228/285 [80%]), but a lower detection rate for distant metastases (5/7 [71%] vs. 7/7 [100%]) compared with ¹⁸F-FDG PET/CT. A significant association between the maximum standard uptake value (SUVmax) of ¹⁸F-FDG PET and ⁶⁸Ga-FAPI-04 PET was found in the primary cancers (r = 0.691, p < 0.001). In comparison to ¹⁸F-FDG PET/CT, ⁶⁸Ga-FAPI-04 PET/CT upstaged the T stage in five patients while downstaging the N stage in seven patients. ⁶⁸Ga-FAPI-04 PET/CT corrected the overall staging of five patients on¹⁸F-FDG PET/CT.

Conclusion

⁶⁸Ga-FAPI-04 PET/CT is preferable to ¹⁸F-FDG PET/CT for NPC staging in terms of the detection efficiency for primary tumors and lymph node metastasis. This is especially true when evaluating the primary cancer and any spread to contiguous tissues. It is possible to improve the staging assessment of NPC by using ⁶⁸Ga-FAPI-04 PET/CT in conjunction with ¹⁸F-FDG PET/CT.

[68Ga]Ga-FAPI PET/CT Improves the T Staging of Patients with Newly Diagnosed Nasopharyngeal Carcinoma: A Comparison with [18F]F-FDG

PURPOSE

This study aimed to explore the value of [⁶⁸Ga]Ga-labelled fibroblast activation protein inhibitor ([⁶⁸Ga]Ga-FAPI) positron emission tomography/computed tomography (PET/CT) in the initial staging of patients with newly diagnosed nasopharyngeal carcinoma (NPC), compared with 2-deoxy-2[¹⁸F]fluoro-D-glucose ([¹⁸F]F-FDG) PET/CT.

MATERIALS AND METHODS

Forty-seven treatment-naïve patients with newly diagnosed NPC underwent magnetic resonance imaging (MRI), [⁶⁸Ga]Ga-DOTA-FAPI-04 PET/CT and [¹⁸F]F-FDG PET/CT within 1 week. The diagnostic efficiency of all imaging modalities for evaluating primary tumour extension was compared from the two aspects of soft tissue and bony structure involvement. The accuracy of two PET/CT methods for diagnosing cervical lymph node (CLN) metastases was compared, and MRI served as the standard reference. T and N stages were assessed by MRI, [⁶⁸Ga]Ga-FAPI PET/CT and [¹⁸F]F-FDG PET/CT. Immunohistochemical (IHC) staining for FAP was conducted in 22 of the patients.

RESULTS

[⁶⁸Ga]Ga-FAPI PET/CT outperformed [¹⁸F]F-FDG PET/CT in the assessment of primary tumour invasion in the cavernous sinus (10 vs. 1, p < 0.001) and bony structures (207 vs. 177, p < 0.001). Compared with MRI, [⁶⁸Ga]Ga-FAPI PET/CT upgraded and underestimated T stage in 13 and 2 patients, while [¹⁸F]F-FDG PET/CT upgraded and underestimated T stage in 5 and 13 patients. However, [⁶⁸Ga]Ga-FAPI PET/CT was inferior to [¹⁸F]F-FDG PET/CT in diagnosing positive CLNs based on the analyses of patients, neck sides, neck levels and individual nodes. [⁶⁸Ga]Ga-FAPI PET/CT changed therapeutic schedules in 8 patients because of stage group changes. The presence of FAP with high quantity and intensity in cancer-associated fibroblasts (CAFs) was confirmed in all tumour specimens.

CONCLUSION

[⁶⁸Ga]Ga-FAPI PET/CT outperformed [¹⁸F]F-FDG PET/CT in detecting the cavernous sinus and bony structure involvement of primary NPC tumours, suggesting its value in improving T staging and therapeutic regimen selection. However, the performance of [⁶⁸Ga]Ga-FAPI PET/CT is less promising for N staging because it detected fewer positive CLNs than [¹⁸F]F-FDG PET/CT.

The role of PET/CT in radiotherapy for nasopharyngeal carcinoma

Radiotherapy has already been developed as the standard of care for patients with nasopharyngeal carcinoma (NPC), and precision staging, target volume delineation, prognosis prediction, and post-treatment surveillance are essential in the management of NPC. Positron emission tomography/computed tomography (PET/CT) is increasingly recognized as an imaging modality to guide precision radiotherapy in these areas. The feasibility and efficacy of 18F-FDG PET/CT have been confirmed in tumor diagnosis, treatment planning, prognosis, surveillance, and assessment. Coupled with the capability of revealing tumor metabolic information, 18F-FDG PET/CT is more accurate in identifying primary lesions and metastases of NPC than other conventional imaging methods including CT and MRI and shows the independently diagnostic and prognostic value for radiotherapy. However, 18F-FDG has limitations due to its physiological distribution in brain tissue and increasing uptake in post-radiation inflammation. Novel PET radiotracers including FAPI, NaF, CHO, and FLT are explored as alternatives with potential superiority for radiotherapy in NPC. In this review, we summarized the evolving role of PET/CT in the management of radiotherapy in NPC patients, aiming to facilitate precision radiotherapy from a molecular imaging aspect.

Pretreatment [18F]FDG PET/CT and MRI in the prognosis of nasopharyngeal carcinoma

OBJECTIVE

The present study aimed to assess the prognostic interest of metabolic and anatomic parameters derived from 2-deoxy-2-[¹⁸F]fluoro-D-glucose positron emission tomography/computed tomography ([¹⁸F]FDG PET/CT) and head and neck magnetic resonance imaging (HN-MRI) for better management of nasopharyngeal carcinoma (NPC).

METHODS

In this study, pre-treatment [¹⁸F]FDG PET/CT and HN-MRI parameters of NPC patients diagnosed between January 2017 and December 2018, were prospectively investigated. Correlation between those parameters and 4-year patient's survival outcomes was evaluated using Kaplan-Meier and Cox-regression analyses.

RESULTS

Our results revealed a significant association between pre-treatment nodal-maximum standardized uptake value (N-SUV max) and N categories (p = 0.01), between pre-treatment node-to-tumor SUV ratio (NTR) and both tumor size (p = 0.01) and N categories (p = 0.009), as well as between metabolic tumor volume (MTV) and both tumor size and NPC overall stage (p < 0.000). In multivariate analyses, pre-treatment N-SUV max, NTR and MTV were significant independent predictors of overall survival, distant metastasis-free survival, and progression-free survival (PFS) (p < 0.05). N-SUV max and MTV were also found to be significant independent predictors of loco-regional recurrence-free survival (p < 0.05), whereas HN-MRI detection of skull-base bone invasion was an independent factor associated with worse PFS in NPC (p = 0.03).

CONCLUSIONS

The present study highlights N-SUV max, NTR and MTV derived from [¹⁸F]FDG PET/CT, and skull-base bone invasion defined by HN-MRI, as promising metabolic and anatomic prognosis biomarkers for NPC.

Development and validation of radiologic scores for guiding individualized induction chemotherapy in T3N1M0 nasopharyngeal carcinoma

OBJECTIVES

We aimed to develop and validate radiologic scores from [¹⁸F]FDG PET/CT and MRI to guide individualized induction chemotherapy (IC) for patients with T3N1M0 nasopharyngeal carcinoma (NPC).

METHODS

A total of 542 T3N1M0 patients who underwent pretreatment [¹⁸F]FDG PET/CT and MRI were enrolled in the training cohort. A total of 174 patients underwent biopsy of one or more cervical lymph nodes. Failure-free survival (FFS) was the primary endpoint. The radiologic score, which was calculated according to the number of risk factors from the multivariate model, was used for risk stratification. The survival difference of patients undergoing concurrent chemoradiotherapy (CCRT) with or without IC was then compared in risk-stratified subgroups. Another cohort from our prospective clinical trial (N = 353, NCT03003182) was applied for validation.

RESULTS

The sensitivity of [¹⁸F]FDG PET/CT was better than that of MRI (97.7% vs. 87.1%, p < 0.001) for diagnosing histologically proven metastatic cervical lymph nodes. Radiologic lymph node characteristics were independent risk factors for FFS (all p < 0.05). High-risk patients (n = 329) stratified by radiologic score benefited from IC (5-year FFS: IC + CCRT 83.5% vs. CCRT 70.5%; p = 0.0044), while low-risk patients (n = 213) did not. These results were verified again in the validation cohort.

CONCLUSIONS

T3N1M0 patients were accurately staged by both [¹⁸F]FDG PET/CT and MRI. The radiologic score can correctly identify high-risk patients who can gain additional survival benefit from IC and it can be used to guide individualized treatment of T3N1M0 NPC.

KEY POINTS

• [¹⁸F]FDG PET/CT was more accurate than MRI in diagnosing histologically proven cervical lymph nodes. • Radiologic lymph node characteristics were reliable independent risk factors for FFS in T3N1M0 nasopharyngeal carcinoma patients. • High-risk patients identified by the radiologic score based on [¹⁸F]FDG PET/CT and MRI could benefit from the addition of induction chemotherapy.

Somatostatin receptor imaging with [68Ga]Ga-DOTATATE positron emission tomography/computed tomography (PET/CT) in patients with nasopharyngeal carcinoma

PURPOSE

To explore the feasibility of [⁶⁸Ga]Ga-DOTATATE positron emission tomography/computed tomography (PET/CT) in patients with non-keratinizing nasopharyngeal carcinoma (NPC) and to evaluate whether [⁶⁸Ga]Ga-DOTATATE PET/CT could be used for non-invasive determination of somatostatin receptor 2 (SSTR2) expression in NPC.

METHODS

This prospective study included patients with NPC who underwent [⁶⁸Ga]Ga-DOTATATE PET/CT between February and May 2021. The [⁶⁸Ga]Ga-DOTATATE and [¹⁸F]FDG uptakes in primary and metastatic NPC lesions were calculated and compared, and the [⁶⁸Ga]Ga-DOTATATE uptake between SSTR2 score groups was analysed.

RESULTS

A total of 36 participants (25 patients, initial staging; 11 patients, recurrence detection) were included; 33 patients also underwent [¹⁸F]FDG PET/CT for staging/restaging as a part of their routine diagnostic workup. [⁶⁸Ga]Ga-DOTATATE PET/CT showed an intense tracer uptake in primary and metastatic NPC lesions. The radiotracer uptake was higher with [⁶⁸Ga]Ga-DOTATATE than with [¹⁸F]FDG PET in primary NPC lesions (SUVmax: 12.03 vs. 10.07, P = 0.048; tumour-to-brain ratio: 36.16 vs. 0.86, P < 0.001) and regional lymph node metastases (median SUVmax: 9.11 vs. 6.12, P < 0.001) and comparable in bone and visceral metastases. Importantly, most NPC lesions showed intense SSTR2 expression (85.7%), which was strongly correlated with the [⁶⁸Ga]Ga-DOTATATE uptake. The SUVmax of SSTR2-negative lesions was significantly lower than that of SSTR2-positive lesions (SUVmax: 4.95 vs. 12.61, P = 0.013).

CONCLUSION

[⁶⁸Ga]Ga-DOTATATE PET/CT is a promising imaging modality for detecting primary and metastatic NPC, with favourable image contrast and comparable diagnostic efficacy when compared to [¹⁸F]FDG PET/CT. An intense SSTR2 expression was observed in most NPCs, and this expression was significantly correlated with the [⁶⁸Ga]Ga-DOTATATE uptake.

Benefit of [18F]-FDG PET/CT for treatment-naïve nasopharyngeal carcinoma

Background

To test the advantages of positron emission tomography and computed tomography (PET/CT) for diagnosing lymph nodes and staging nasopharyngeal carcinoma and to investigate its benefits for survival and treatment decisions.

Methods

The performance of PET/CT and magnetic resonance imaging (MRI) in diagnosis was compared based on 460 biopsied lymph nodes. Using the propensity matching method, survival differences of T3N1M0 patients with (n = 1093) and without (n = 1377) PET/CT were compared in diverse manners. A radiologic score model was developed and tested in a subset of T3N1M0 patients.

Results

PET/CT performed better than MRI with higher sensitivity, accuracy, and area under the receiver operating characteristic curve (96.7% vs. 88.5%, p < 0.001; 88.0% vs. 81.1%, p < 0.001; 0.863 vs. 0.796, p < 0.05) in diagnosing lymph nodes. Accordingly, MRI-staged T3N0-3M0 patients showed nondifferent survival rates, as they were the same T3N1M0 if staged by PET/CT. In addition, patients staged by PET/CT and MRI showed higher survival rates than those staged by MRI alone (p < 0.05), regardless of the Epstein-Barr virus DNA load. Interestingly, SUVmax-N, nodal necrosis, and extranodal extension were highly predictive of survival. The radiologic score model based on these factors performed well in risk stratification with a C-index of 0.72. Finally, induction chemotherapy showed an added benefit (p = 0.006) for the high-risk patients selected by the model but not for those without risk stratification (p = 0.78).

Conclusion

PET/CT showed advantages in staging nasopharyngeal carcinoma due to a more accurate diagnosis of lymph nodes and this contributed to a survival benefit. PET/CT combined with MRI provided prognostic factors that could identify high-risk patients and guide individualized treatment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00259-021-05540-8.

Subregional Radiomics Analysis of PET/CT Imaging with Intratumor Partitioning: Application to Prognosis for Nasopharyngeal Carcinoma

PURPOSE

This work aims to identify intratumoral habitats with distinct heterogeneity based on 2-deoxy-2-[¹⁸F]fluro-D-glucose positron emission tomography (PET)/X-ray computed tomography (CT) imaging, and to develop a subregional radiomics approach to predict progression-free survival (PFS) in patients with nasopharyngeal carcinoma (NPC).

PROCEDURES

In total, 128 NPC patients (85 vs. 43 for primary vs. validation cohorts) who underwent pre-treatment PET/CT scan were enrolled retrospectively. Each tumor was partitioned into several phenotypically consistent subregions based on individual- and population-level clustering. For each subregion, 202 radiomics features were extracted to construct imaging biomarker for prognosis via Cox's proportional hazard model combined with forward stepwise feature selection. Relevance of imaging biomarkers and clinicopathological factors were assessed by multivariate Cox regression analysis and Spearman's correlation analysis. To investigate whether imaging biomarkers could provide complementary prognosis information beyond existing predictors, a scoring system was further developed for risk stratification and compared with AJCC staging system.

RESULTS

Three subregions (denoted as S1, S2, and S3) were discovered with distinct PET/CT imaging characteristics in the two cohorts. The prognostic performance of imaging biomarker S3 outperformed the whole tumor (C-index, 0.69 vs. 0.58; log-rank test, p < 0.001 vs. p = 0.552). Imaging biomarker S3 and AJCC stage were identified as independent predictors (p = 0.011 and 0.042, respectively) after adjusting for clinicopathological factors. The scoring system outperformed the traditional AJCC staging system (log-rank test, p < 0.0001 vs. p = 0.0002 in primary cohort and p = 0.0021 vs. p = 0.0277 in validation cohort, respectively).

CONCLUSIONS

Subregional radiomics analysis of PET/CT imaging has the potential to predict PFS in patients with NPC, which also provides complementary prognostic information for traditional predictors.

Impact of FDG-PET/CT on restaging and response evaluation of locally advanced head and neck cancer patient management

Background:

Head and neck cancer (HNC) accounts for 5% of all new cancer cases and most were locally advanced. Positron emission tomography/computed tomography (PET/CT) in radiotherapy practice in locally advanced head and neck squamous cell carcinoma (HNSCC) is being used in staging and proper contouring. Proper staging is essential for accurate treatment decision.

Methods:

This is a prospective phase II study conducted as a single institute centre to evaluate the role of PET/CT-treatment in staging, contouring and response evaluation of 30 patients with locally advanced HNSCC in contrast to CT scan. Our cases did not undergo radical surgery for the primary tumour, and biopsy was taken with PET/CT post-treatment to evaluate response.

Results:

Median age of patients was 49·4 years (minimum age of 32 years and maximum of 68 years). Males were predominant 22 (73·3%). Nasopharynx was the predominant site 16/30 (53·3%). PET/CT changed the overall staging in 40% of the patients (upstaged in 36·7% and downstaged in 3·3%). Gross tumour volume (GTV) of PET/CT was smaller in 23 patients (76·7%) and larger in 5 (16·7%) than the GTV of conventional CT, whereas GTV of lymph nodes of PET/CT was larger in 20 patients (67·7%) and smaller in 4 (13·3%). PET/CT study detected bone metastasis in two nasopharyngeal carcinoma patients and two cases of 2nd primary tumours which were not detected using conventional CT. The Cox-regression model showed that the median standardised uptake volume (SUV) of the initial tumour had been a dependent predictor of death in patients with HNSCC (p-value = 0·033) where the risk of death was 0·725 times among patients with high SUV of the initial tumour. Consequently, the size of GTV of the tumour was significant in the prediction of death (p = 0·018).

Conclusions:

18F-FDG-PET/CT is useful for staging, radiotherapy delineation as well as aiding proper decision making, in addition to assessment of treatment response in HNSCC patients.

The evolution of the nasopharyngeal carcinoma staging system over a 10-year period: implications for future revisions

BACKGROUND

The classification criteria and staging groups for nasopharyngeal carcinoma described in the Union for International Cancer Control/American Joint Committee on Cancer (UICC/AJCC) staging system have been revised over time. This study assessed the proportion of patients whose staging and treatment strategy have changed due to revisions of the UICC/AJCC staging system over the past 10 years (ie, from the sixth edition to the eighth edition), to provide information for further refinement.

METHODS

We retrospectively reviewed 1901 patients with non-metastatic nasopharyngeal carcinoma treated in our cancer center between November 2009 and June 2012. The Akaike information criterion and Harrell concordance index were applied to evaluate the performance of the staging system.

RESULTS

In total, 25 (1.3%) of the 1901 patients who were staged as T2a according to the sixth edition system were downgraded to T1 in the eighth edition; 430 (22.6%) staged as N0 in the sixth edition were upgraded to N1 in the eighth edition; 106 (5.6%) staged as N1/2 in the sixth edition were upgraded to N3 in the eighth edition. In addition, 51 (2.7%) and 25 (1.3%) of the study population were upstaged from stage I to stage II and stage II to stage IVa, respectively; 10 (0.5%) was downgraded from stage II to stage I. The survival curves of adjacent N categories and staging groups defined by eighth classification system were well-separated. However, there was no significant difference in the locoregional failure-free survival (P = 0.730) and disease-free survival (P = 0.690) rates between the T2 and T3 categories in the eighth edition classification system.

CONCLUSIONS

Modifications to the tumor-node-metastasis staging system over the past 10 years have resulted in N classification changes in numerous cases. Although the eighth edition tumor-node-metastasis staging system better predicts survival outcomes, the T classification could be simplified in future revisions.

Bone marrow metastasis/carcinomatosis in head and neck squamous cell carcinoma

BACKGROUND

Literature on bone marrow carcinomatosis in head and neck squamous cell carcinoma (HNSCC) is sparse. This work aims to augment understanding on its characteristic features, clinical presentation, investigations, treatment and outcomes.

METHODS

Comprehensive literature review of all published cases of metastasis of HNSCC to the bone marrow with regard to clinical presentation, diagnosis, treatment and survival outcomes of this disease. Each of these factors is discussed forming an up-to-date review on the subject.

RESULTS

Eight case reports were identified, seven males and one female with an age range of 35-64 years. Primary sites were from the oral cavity (n = 4), oropharynx (n = 3) and supraglottis (n = 1). Six were stage four disease with nodal involvement, one case stage two and one case with unknown staging. Two of the oropharyngeal cancers were p16 positive, and one p16 status was not documented. Five patients presented with back pain, two patients had ecchymoses with bleeding, and one presented with sepsis and thrombocytopaenia. Three patients had proven disseminated intravascular coagulation. Four patients were treated with palliative chemoradiotherapy, one had palliative radiotherapy, one had radiotherapy and dendritic cell vaccine immunotherapy, and two died from the disease prior to any treatment. Various facets of presentation and management are discussed.

CONCLUSION

Bone marrow carcinomatosis from HNSCC is rare. It can present with a variety of non-specific symptoms, and a high index of suspicion is required to be able to diagnose the condition promptly. Aggressive chemotherapy is the treatment of choice but prognosis remains poor.

Clinical utility of [68Ga]Ga-labeled fibroblast activation protein inhibitor (FAPI) positron emission tomography/computed tomography for primary staging and recurrence detection in nasopharyngeal carcinoma

PURPOSE

This study aimed to explore the clinical utility of [⁶⁸Ga]Ga-labeled fibroblast activation protein inhibitor ([⁶⁸Ga]Ga-FAPI) positron emission tomography/computed tomography (PET/CT) relative to [¹⁸F]-fluorodeoxyglucose ([¹⁸F]FDG) PET/CT and magnetic resonance imaging (MRI) for primary staging and recurrence detection in nasopharyngeal carcinoma (NPC).

METHODS

This retrospective analysis utilized a sub-cohort of patients from a previously acquired database. Patients with NPC who underwent [¹⁸F]FDG and [⁶⁸Ga]Ga-FAPI PET/CT between October 2019 and November 2020 were included. The radiotracer uptake and clinical staging/restaging performances of [¹⁸F]FDG and [⁶⁸Ga]Ga-FAPI PET/CT were compared.

RESULTS

Forty-five participants (39 for initial assessment, 6 for recurrence detection) were included. In treatment-naïve participants, [⁶⁸Ga]Ga-FAPI PET/CT showed higher radiotracer uptake than [¹⁸F]FDG PET/CT in primary tumors (16.18 vs. 10.11, P < 0.001), regional lymph nodes (11.42 vs. 7.37, P < 0.001), and bone and visceral metastases (6.94 vs. 3.11, P < 0.001). Compared with the [¹⁸F]FDG-based TNM stage, the [⁶⁸Ga]Ga-FAPI-based TNM stage was upgraded in ten patients (26%), resulting in management changes in seven patients (18%). Compared with MRI, [⁶⁸Ga]Ga-FAPI PET/CT upgraded and underestimated the T stage in four and two patients, respectively. In post-treatment patients, [⁶⁸Ga]Ga-FAPI PET/CT yielded more true-positive findings than [¹⁸F]FDG PET/CT in detecting local recurrence.

CONCLUSION

[⁶⁸Ga]Ga-FAPI PET/CT is a promising imaging modality for the diagnosis of primary and metastatic NPC. The exact tumor geographic imaging obtained through [⁶⁸Ga]Ga-FAPI PET/CT may be a supplement to MRI for T staging and radiotherapy planning.

A head-to-head comparison of 68Ga-DOTA-FAPI-04 and 18F-FDG PET/MR in patients with nasopharyngeal carcinoma: a prospective study

PURPOSE

To conduct a head-to-head comparison of the diagnostic ability of ⁶⁸Ga-DOTA-FAPI-04 (⁶⁸Ga-FAPI) and ¹⁸F-FDG PET/MR in nasopharyngeal carcinoma (NPC) patients.

METHODS

Patients diagnosed with NPC were prospectively enrolled. All patients underwent head-and-neck ⁶⁸Ga-FAPI PET/MR and ¹⁸F-FDG PET/MR within 1 week. Primary tumor, lymph node numbers, and tracer uptake were compared by SUVmax and visual evaluation. The primary tumor volumes derived from ⁶⁸Ga-FAPI, ¹⁸F-FDG PET, and MRI were also compared.

RESULTS

Fifteen patients were enrolled from June to August 2020. Both ⁶⁸Ga-FAPI and ¹⁸F-FDG PET had 100% detection rate of the primary tumor. The ⁶⁸Ga-FAPI SUVmax of primary tumors (13.87 ± 5.13) was lower than that of ¹⁸F-FDG (17.73 ± 6.84), but the difference was not significant (p = 0.078). Compared with ¹⁸F-FDG, ⁶⁸Ga-FAPI PET improved the delineation of skull-base invasion in eight out of eight patients and intracranial invasion in four out of four patients. When 25%SUVmax of ⁶⁸Ga-FAPI or 20%SUVmax of ¹⁸F-FDG was utilized as a threshold for determining tumor volume, it was highly consistent with MRI. ¹⁸F-FDG PET detected much more positive lymph nodes than ⁶⁸Ga-FAPI (100 vs 48). The SUVmax of 48 paired lymph nodes was significantly lower on ⁶⁸Ga-FAPI than ¹⁸F-FDG (8.67 ± 3.88 vs 11.79 ± 6.17, p < 0.001). Additionally, ⁶⁸Ga-FAPI further detected four highly suspected small, distant metastases in three patients. Compared with ¹⁸F-FDG, ⁶⁸Ga-FAPI changed overall staging in six of fifteen patients, with three patients being up-staged, and three down-staged.

CONCLUSION

⁶⁸Ga-FAPI outperforms ¹⁸F-FDG in delineating the primary tumor and detecting suspected distant metastases, particularly in the evaluation of skull-base and intracranial invasion, suggesting ⁶⁸Ga-FAPI hybrid PET/MR has the potential to serve as a single-step staging modality for patients with NPC. However, its value regarding lymph node and distant metastases evaluation needs further study.

TRIAL REGISTRATION

NCT04554719. Registered September 8, 2020 - retrospectively registered, http://clinicaltrails.gov/show/NCT04554719.

Impact of 18F-2-fluoro-2-deoxy-D-glucose PET/computerized tomography on the initial staging and changing the management intent in head and neck squamous cell carcinoma

OBJECTIVE

To assess the role of 18F-FDG PET/CT in initial staging of head and neck squamous cell carcinoma and its impact on changing the management compared to other conventional methods.

PATIENTS AND METHODS

A prospective study of 31 patients (21 male and 10 female), mean age 49.3 ± 12.1 years with histologically confirmed squamous cell carcinoma of the head and neck (nasopharynx was the commonest cancer in 15 patients (48.4%), poorly differentiated grade represented 64.5% of all tumors. Initial staging was achieved according to routine physical examination, endoscopy, CT, U/S, MRI.

RESULTS

The overall change in TNM staging by 18F-FDG PET/CT in relation to conventional methods was encountered in 15/31 patients (48.4%). PET/CT changed; T staging in three patients (9.6%), upstaging in two patients and downstaging in one patient. PET/CT upstaged all 13/31 patients in N staging (41.9%). 18F-FDG PET/CT changed; M staging in 3/31 (9.6%) patients, upstaging in two and downstaging in one patient. PET/CT results caused radiotherapy modification in 21/31 patients (67.7%). PET/CT detected intra-parotid nodule in four patients, so additional radiation was added to the parotid in the treatment field. Retropharyngeal nodes were detected by PET/CT in three patients that were missed by conventional imaging. 18F-FDG PET/CT detected two patients of thyroid papillary carcinoma and one case of sigmoid neoplasm confirmed by histopathology.

CONCLUSION

18F-FDG-PET/CT is considered a valuable diagnostic test in head and neck squamous cell carcinoma at initial assessment which would change staging and radiotherapy planning and hence proper management.

Low value of whole-body dual-modality [18f]fluorodeoxyglucose positron emission tomography/computed tomography in primary staging of stage I-II nasopharyngeal carcinoma: a nest case-control study

Objectives

The value of using PET/CT for staging of stage I–II NPC remains unclear. Hence, we aimed to investigate the survival benefit of PET/CT for staging of early-stage NPC before radical therapy.

Methods

A total of 1003 patients with pathologically confirmed NPC of stages I–II were consecutively enrolled. Among them, 218 patients underwent both PET/CT and conventional workup ([CWU], head-and-neck MRI, chest radiograph, liver ultrasound, bone scintigraphy) before treatment. The remaining 785 patients only underwent CWU. The standard of truth (SOT) for lymph node metastasis was defined by the change of size according to follow-up MRI. The diagnostic efficacies were compared in 218 patients who underwent both PET/CT and CWU. After covariate adjustment using propensity scoring, a cohort of 872 patients (218 with and 654 without pre-treatment PET/CT) was included. The primary outcome was overall survival based on intention to treat.

Results

Retropharyngeal lymph nodes were metastatic based on follow-up MRI in 79 cases. PET/CT was significantly less sensitive than MRI in detecting retropharyngeal lymph node lesions (72.2% [62.3–82.1] vs. 91.1% [84.8–97.4], p = 0.004). Neck lymph nodes were metastatic in 89 cases and PET/CT was more sensitive than MRI (96.6% [92.8–100.0] vs. 76.4% [67.6–85.2], p < 0.001). In the survival analyses, there was no association between pre-treatment PET/CT use and improved overall survival, progression-free survival, local relapse-free survival, regional relapse-free survival, and distant metastasis-free survival.

Conclusions

This study showed PET/CT is of little value for staging of stage I–II NPC patients at initial imaging.

Key Points

• PET/CT was more sensitive than MRI in detecting neck lymph node lesions whereas it was significantly less sensitive than MRI in detecting retropharyngeal lymph node lesions.

• No association existed between pre-treatment PET/CT use and improved survival in stage I–II NPC patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-020-07478-1.

Effect of Induction Chemotherapy in Nasopharyngeal Carcinoma: An Updated Meta-Analysis

Background

Previous meta-analysis had evaluated the effect of induction chemotherapy in nasopharyngeal carcinoma. But two trials with opposite findings were not included and the long-term result of another trial significantly differed from the preliminary report. This updated meta-analysis was thus warranted.

Methods

Literature search was conducted to identify randomized controlled trials focusing on the additional efficacy of induction chemotherapy in nasopharyngeal carcinoma. Trial-level pooled analysis of hazard ratio (HR) for progression free survival and overall survival and risk ratio (RR) for locoregional control rate and distant control rate were performed.

Results

Twelve trials were eligible. The addition of induction chemotherapy significantly prolonged both progression free survival (HR=0.68, 95% confidence interval [CI] 0.60–0.76, p<0.001) and overall survival (HR=0.67, 95% CI 0.54–0.80, p<0.001), with 5-year absolute benefit of 11.31% and 8.95%, respectively. Locoregional (RR=0.80, 95% CI 0.70–0.92, p=0.002) and distant control (RR=0.70, 95% CI 0.62–0.80) rates were significantly improved as well. The incidence of grade 3–4 adverse events during the concurrent chemoradiotherapy was higher in leukopenia (p=0.028), thrombocytopenia (p<0.001), and fatigue (p=0.038) in the induction chemotherapy group.

Conclusions

This meta-analysis supported that induction chemotherapy could benefit patients with nasopharyngeal carcinoma in progression free survival, overall survival, locoregional, and distant control rate.

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.

MR-guided simulation is superior than FDG/PET-guided simulation for local control in nasopharyngeal cancer patients treated with intensity-modulated radiotherapy

BACKGROUND

MRI and PET/CT scans are the main supportive methods for nasopharyngeal cancer (NPC) for staging and planning. The aim of this study is to compare MRI and PET/CT scanning in terms of survival in patients with NPC who had MRI or PET/CT-simulated radiotherapy planning.

METHODS

Pathological diagnosed nonkeratinized undifferentiated type and stage II-IVA 91 NPC patients with treated intensity-modulated radiotherapy plus chemotherapy were scanned. The patients were immobilized by a customized thermoplastic mask for fusion images both MRI scans and PET/CT scans. CTVs were created via MR-guided simulation and PET/CT-guided simulation.

RESULTS

PET/CT-guided simulation was performed with 44 patients (56.4%) and MR-guided simulation was performed with 34 patients (43.6%). Local recurrence-free survival (LRFS) of patients was 68.1 months. LRFS of patients with PET/CT-guided simulation was 59.9, while LRFS of patients with MR-guided was 66.9 months. There was a statistically significant difference between groups (P = .03). In the subgroup analyses, the patients were assessed by dividing into the three groups for the T1-T2 stage, T-3 stage, and T-4 stage. In the patients with T1-T2 stage, 5-year LRFS rates were found %74.4 for PET/CT-guided simulation and %83.3 for MR-guided simulation. There was no statistically significant difference between groups (P = .33). In the patients with T-3 stage, 5-year LRFS rates were found %55.6 for PET/CT-guided simulation and %83.3 for MR-guided simulation. There was not a statistically significant difference between groups (P = .59). In the patients with T-4 stage, 5-year LRFS rates were found %42.2 for PET/CT-guided simulation and %85.1 for MR-guided simulation. The difference between groups was found to be statistically significant (P = .04).

CONCLUSION

In this study, we founded that MR-guided simulation has better than PET/CT-guided simulation for LRFS.

Bone Metastases Pattern in Newly Diagnosed Metastatic Nasopharyngeal Carcinoma: A Real-World Analysis in the SEER Database

Objective

To evaluate the prevalence rate and survival situation of bone metastases in initial nasopharyngeal carcinoma (NPC) patients and the hazard and forecast elements of bone metastases NPC patients. Patients and Methods. The data collected from Surveillance, Epidemiology, and End Results (SEER) program between 2010 and 2016 were evaluated. Univariate and multivariable logistic analysis and the Cox regression were carried out to estimate predictors and elements of the being of bone metastases at diagnosis, respectively. The overall survival of different subgroups were appraised by log-rank tests and the Kaplan–Meier analysis.

Results

Factors including male sex, higher N stage, presence of liver, and brain or lung metastases were largely related to the occurrence of bone metastases. The median survival time for bone metastasis NPC patients was 14.0 months. A factor of more than one primary sequence number predicted worse survival.

Conclusion

The data offer corresponding risks and prognostic indicators of bone metastases for NPC patients.

Prognostic significance of quantitative metastatic lymph node burden on magnetic resonance imaging in nasopharyngeal carcinoma: A retrospective study of 1224 patients from two centers

BACKGROUND AND PURPOSE

The number of metastatic lymph nodes (LNs) has been demonstrated to be an important prognosticator in some head and neck cancers. This study aimed to examine its prognostic value in nasopharyngeal carcinoma (NPC).

MATERIALS AND METHODS

Patients with newly-diagnosed, non-distant metastatic NPC from two centers were enrolled in this study. According to the radiologic criteria for involved LNs, the number of positive LNs was assessed on MRI. Univariate and multivariate models were constructed to assess the association between the number of positive LNs and clinical outcomes. Exhaustive method was used to determine the cutoff values of the number of positive LNs.

RESULTS

In 1224 patients, the number of MRI-positive LNs was an independent risk factor for overall survival (OS), distant metastasis-free survival (DMFS), relapse-free survival (RFS), progression-free survival (PFS) and regional relapse-free survival (RRFS), surpassing other nodal factors. All the patients were divided into no, low (1-4 positive LNs), moderate (5-9 positive LNs) and high (>9 positive LNs) risk groups. The HRs of high-risk group exceeded the HRs of N3 classification for OS, DMFS, RFS, PFS and RRFS. On upgrading patients with more than 9 positive LNs from N2 to N3, the revised N-staging system showed a higher C-index compared to current N-staging system for predicting OS (0.747 vs. 0.741, P = 0.002), RFS (0.655 vs. 0.640, P = 0.015) and PFS (0.674 vs. 0.669, P = 0.035).

CONCLUSIONS

The number of MRI-positive LNs was a predominant independent prognostic factor for NPC patients' survival. It may be incorporated into the future N-staging system to improve its accuracy in predicting outcomes.

Lymph node-to-primary tumor standardized uptake value ratio on PET predicts distant metastasis in nasopharyngeal carcinoma

OBJECTIVES

To investigate the prognostic value of the relative maximum standardized uptake value (SUV) ratio between neck lymph node and primary tumor (NTR) measured by pretreatment ¹⁸F-FDG PET in patients with nasopharyngeal carcinoma (NPC).

MATERIALS AND METHODS

We retrospectively reviewed patients with non-disseminated NPC who underwent PET scans before radical intensity-modulated radiotherapy (IMRT). Receiver operating characteristic analysis was performed to identify the optimal cut-off value for NTR. The prognostic value of NTR for distant metastasis-free survival (DMFS) was evaluated using Kaplan-Meier method for survival analyses and Cox regression for multivariable analysis.

RESULTS

Among the 437 eligible patients, the median follow-up time was 62.9 (range, 2.1-113.0) months. Patients with high NTR (NTR > 0.9181) experienced significantly worse DMFS (5-year 80.5% vs. 91.6%, P < 0.001). In the subgroup analysis, we found that patients with high NTR had significantly lower DMFS in T1-2 category (5-year 86.1% vs. 98.1%, P = 0.002), T3-4 category (5-year 71.5% vs. 86.2%, P = 0.010), N2-3 category (5-year 75.3% vs. 86.2%, P = 0.048), and stage IVA-B (5-year 69.8% vs. 85.4%, P = 0.012). Multivariable analysis showed that NTR was an independent prognostic factor for DMFS (HR 2.20, 95% CI 1.20-4.03, P = 0.011).

CONCLUSION

Pretreatment NTR is an easily accessible but potential prognosticator for DMFS in NPC patients treated by IMRT, which may help in providing more personalized treatment or designing future clinical trials.

Multiparametric positron emission tomography/magnetic resonance imaging in nasopharyngeal carcinoma: Correlations between magnetic resonance imaging functional parameters and 18F-fluorodeoxyglucose positron emission tomography imaging biomarkers and their predictive value for treatment failure

Objectives:

The clinical significance of positron emission tomography/magnetic resonance imaging (PET/MRI) functional parameters in nasopharyngealcarcinoma (NPC) remains unclear. The purpose of this prospective study was two-fold: (1) to investigate the associations between simultaneously acquired PET/MRI perfusion, diffusion, and glucose metabolism parameters in patients with NPC and (2) to analyze their predictive value with respect to treatment failure.

Materials and Methods:

We enrolled 85 patients with primary NPC who simultaneously underwent¹⁸F-fluorodeoxyglucose PET/CT and PET/MRI before definitive treatment. The following variables were determined: (1) functional parameters from the MRI component, including perfusion values (K^trans,k_ep,v_e, and initial area under the enhancement curve) and apparent diffusion coefficient (ADC) values, and (2) PET parameters, including metabolic tumor volume (MTV). The reciprocal interrelationships between these parameters and their correlations with treatment failure were examined.

Results:

We observed significant negative associations between K^trans and ADC (r = −0.215, P = 0.049) as well as between v_e and ADC (r = −0.22, P = 0.04). Correlations between PET and MRI functional parameters were not statistically significant. Treatment failures were observed in 21.2% of patients without distant metastases. Multivariate analysis identified v_e as a significant independent predictor for treatment failure (P = 0.022), whereas MTV showed a borderline significance (P = 0.095). Patients in whom both v_e and MTV values were increased had a significantly higher rate of treatment failure (62.5%) than those with either one (21.9%) or no (7.7%) increased parameter (P = 0.004).

Conclusion:

Correlation analyses revealed complex interrelationships among PET and MRI indices measured in patients with NPC. These parameters may have a complementary role in predicting treatment failure in this clinical setting.

Prognostic value of maximum standard uptake value, metabolic tumor volume, and total lesion glycolysis of positron emission tomography/computed tomography in patients with breast cancer: A systematic review and meta-analysis

Purpose

A comprehensive systematic review of the literature was conducted on parameters from ¹⁸ F-FDG PET and a meta-analysis of the prognostic value of the maximal standard uptake value (SUVmax), metabolic tumor volume (MTV) and total lesional glycolysis (TLG) in patients with breast cancer (BC).

Patients and methods

Relevant English articles from PubMed, EMBASE, and the Cochrane Library were retrieved. Pooled hazard ratios (HRs) were used to assess the prognostic value of SUVmax, MTV, and TLG.

Results

A total of 20 primary studies with 3115 patients with BC were included. The combined HRs (95% confidence interval [CI] of higher SUVmax and higher TLG for event-free survival (EFS) were 1.53 (95% CI, 1.25–1.89, P = 0.0006) and 5.94 (95% CI, 2.57–13.71, P = 0.97), respectively. Regarding the overall survival (OS), the combined HRs were 1.22 (95%CI, 1.02–1.45, P = 0.0006) with higher SUVmax, and 2.91(95% CI, 1.75–4.85, P = 0.44) with higher MTV. Higher MTV showed no correlation with EFS [1.31(95% CI, 0.65–2.65, P = 0.18)] and similarly higher TLG showed no correlation with OS [1.20(95% CI, 0.65–2.23, P = 0.45)]. Subgroup analysis showed that SUVmax, with a median value of 5.55 was considered as a significant risk factor for both EFS and OS in BC patients.

Conclusion

Despite clinically heterogeneous BC patients and adoption of various methods between studies, the present meta-analysis results confirmed that patients with high SUVmax are at high risk of adverse events or death in BC patients, high MTV predicted a high risk of death and high TLG predicted a high risk of adverse events.

Preliminary clinical results for PET/MR compared with PET/CT in patients with nasopharyngeal carcinoma

The present study aimed to assess the performance of positron emission tomography-magnetic resonance imaging (PET/MR) for the visualization and characterization of lesions. In addition, the present study investigated whether the apparent diffusion coefficient (ADC) and intravoxel incoherent motion parameters exhibited any significant correlation with standardized uptake values (SUV) in patients with nasopharyngeal carcinoma (NPC). A total of 35 patients with NPC underwent whole body PET-computed tomography (CT) and head and neck MR imaging (MRI) scans using the PET/CT-MRI system. Image quality, lesion conspicuity and the diagnostic confidence of PET/CT, T1 weighted (T1w) PET/MR and T2w PET/MR imaging were assessed. The true diffusion coefficient (D), the pseudo-diffusion coefficient or diffusion within the microcirculation (D*), and the perfusion fraction or the contribution of water moving in the capillaries (f), and ADC, were calculated. The correlation between the ADC, D*, D and f values and the SUV were analyzed using Pearson's correlation analysis. Similar image quality was obtained using PET/CT, T1w PET/MR and T2w PET/MR imaging. However, the T1w PET/MR and T2w PET/MR imaging were more effective than PET/CT in analyzing the lesion conspicuity of the primary tumors and lymph nodes. In addition, T2w PET/MR imaging was more efficient than T1w PET/MR imaging in analyzing primary tumors and lymph nodes. Pearson's correlation analysis showed no significant correlation between the SUV and ADC, and D*, D and f values in NPC. The present results suggested that the application of PET/MR is feasible and could serve as a reliable alternative to PET/CT, while SUV and ADC, D*, D and f values were identified as independent biomarkers in NPC.

The evolution of nasopharyngeal carcinoma staging

The prevalence of nasopharyngeal carcinoma is characterized by an unbalanced distribution: the disease is particularly prevalent in East and Southeast Asia. In this article, we review the evolution of the International Union Against Cancer/American Joint Committee on Cancer staging system for nasopharyngeal carcinoma. With the increasing using of newer imaging methods, more advanced radiotherapy techniques and systemic chemotherapy, we also discuss newer clinical features that might affect staging. Finally, we propose the future direction of staging and potential prognostic factors that have a major influence on the treatment outcomes of this disease.

Ultrasound Elastography supplement assessing nodal status of magnetic resonance imaging staged cervical N0 patients with nasopharyngeal carcinoma

Background

To determine whether ultrasound elastography can distinguish reactive or metastatic small lymph nodes (sLN) of magnetic resonance imaging (MRI) staged cervical N0 patients with nasopharyngeal carcinoma (NPC).

Methods

A pilot study was performed involving the diagnostic performances of conventional high-frequency ultrasound (CHFU) and/or shear wave elastography (SWE) for predicting metastases in sLN of MRI-staged N0 NPC patients with reference to the histologically-proven ultrasound guided core needle biopsy (US-CNB). The diagnosis of CHFU was based on the superficial lymph node ultrasonic criteria with the five-point-scale (FPS). The mean (Emean), minimum (Emin) and maximum (Emax) of the elasticity indices were measured by SWE at the stiffest part of the sLN in kilopascal. Diagnostic performances were analyzed using a receiver operating curve (ROC) on a per-node basis. The authenticity of this article has been validated by uploading the key raw data onto the Research Data Deposit public platform (http://www.researchdata.org.cn), with the approval RDD number as RDDA2017000447.

Results

All 113 cervical sLN of 49 MRI-staged cervical N0 NPC patients underwent evaluation of CHFU and SWE; 38 sLN (FPS < 2) were regarded as benign, which were excluded from subsequent analysis due to none biopsy-proven. And 75 indeterminate sLN (FPS ≥ 2) were referred to US-CNB and revealed 15 (20%) metastases. All SWE elastic indices were significantly higher in malignant sLNs than in benign sLNs (p < 0.05). Moreover, Emax exhibited the highest diagnostic value (AUC:0.733 ± 0.067, p = 0.005) with excellent measurement reproducibility (ICC: 0.786; 95%CI: 0.684, 0.864). CHFU plus SWE was superior to CHFU or SWE alone for predicting metastases in sLN of MRI-staged N0 patients with NPC (p < 0.001).

Conclusions

CHFU plus SWE is an optional non-invasive modality to supplement MRI in assessing cervical nodal status of patients with NPC.

Electronic supplementary material

The online version of this article (10.1186/s40644-019-0199-3) contains supplementary material, which is available to authorized users.

Clinical application of diffusion-weighted magnetic resonance imaging in radiotherapy for nasopharyngeal carcinoma

OBJECTIVE

To explore the clinical application of diffusion-weighted magnetic resonance imaging (DWI) in nasopharyngeal carcinoma (NPC) diagnosis, detection of lymph node metastasis, radiotherapy and prognosis.

METHODS

Twenty patients with diagnosed NPC in an early stage of radiotherapy were enrolled in our department between May 2010 and May 2013. T1 and T2 weighted magnetic resonance imaging and DWI of the nasopharynx and neck were performed 1 week before radiotherapy, during radiotherapy at a dose of 60 Gy, and 1 month after radiotherapy. Pertinent measurements and related data were recorded.

RESULTS

In comparison with that before radiotherapy, the ADC value of the nasopharyngeal primary lesion increased significantly during radiotherapy at a dose of 60 Gy and at 1 month after radiotherapy (F = 187.160, P = 0.000). When the dose of radiotherapy reached 60 Gy, the DWI signals from both the neck and the retropharyngeal lymph nodes were significantly lower than those before radiotherapy.

CONCLUSION

DWI can be used for sensitive and accurate diagnosis of lymph node metastasis in the neck and retropharyngeal space, monitoring of the radiotherapy effect in early stages of NPC and development of new medical treatment strategies.

FDG PET/CT and Conventional Imaging Methods in Cancer of Unknown Primary: an Approach to Overscanning

Purpose

To compare the performance of fluorine-18 fluorodeoxyglucose positron emission tomography and computed tomography (FDG PET/CT) with conventional imaging methods (CIM), including computed tomography (CT), magnetic resonance imaging (MRI), and mammography (MMG) in cancer of unknown primary (CUP).

Methods

A total of 36 patients with CUP, who referred to our clinic for a FDG PET/CT scan, were enrolled in this study. Thirty of the patients were also examined through either diagnostic CT/MRI and/or MMG. The diagnostic performance of both methods for the primary cancer location was analyzed. The results of FDG PET/CT and CIM were compared based on the standard reference of the histopathology and/or clinical and laboratory follow-up.

Results

The primary cancer locations were detected in 24 patients (66.6%, 24/36) by FDG PET/CT, whereas CIM identified the locations in 16 patients (53.3%, 16/30). Sensitivity, specificity, PPV, NPV, and accuracy rates of the detection of the primary tumor localizations were as follows: 83, 70, 89, 58, and 79% for FDG PET/CT; 70, 62, 84, 42, and 68% for CIM, respectively. There was no statistical significance between modalities regarding any of the categories in 30 patients.

Conclusion

FDG PET/CT detected the primary tumors of the patients with CUP more than CIM did. However, the difference between them was not found to be statistically significant. It may be considered that FDG PET/CT scan can be performed as a first-line tool in the initial diagnosis of the patients with CUP and to add radiodiagnostic imaging in selective cases. We conclude that if the first-line examination of a CUP patient has been already performed by a CIM and the result was negative or inconclusive, FDG PET/CT can be considered to avoid unnecessary imaging procedures.

Diagnostic value of diffusion-weighted magnetic resonance imaging for local and skull base recurrence of nasopharyngeal carcinoma after radiotherapy

Tumor recurrence is a major cause of nasopharyngeal carcinoma (NPC) treatment failure. Diffusion-weighted imaging (DWI) is used for a variety of cancers, but few data are available for NPC.The aim of the study was to investigate the DWI features of recurrent NPC after radiotherapy and apparent diffusion coefficient (ADC) thresholds for the diagnosis of recurrent NPC.This was a retrospective study of 160 patients with NPC treated by radiotherapy at the Cancer Hospital affiliated to Guangxi Medical University from May 2012 to March 2015. The patients were divided into the local recurrence (n = 39), fibrosis (n = 51), clivus recurrence (n = 22), and clivus nonrecurrence (n = 48) groups. The patients underwent magnetic resonance imaging (MRI), enhanced MRI, and DWI. Receiver operating characteristics curves were used to determine sensitivity, specificity, and negative predictive values.ADC values were significantly different between the recurrence and fibrosis groups (P < .0001). Using ADC threshold values of 0.887 × 10 mm/s for local recurrence, the area under the curve (AUC) of DWI was 0.967 (87.2% sensitivity and 94.1% specificity), compared with 0.732 for routine MRI (71.8% sensitivity and 74.5% specificity) (P < .001). Using ADC threshold values of 1.018 × 10 mm/s for the diagnosis of clivus recurrent NPC, the AUC of DWI was 0.984 (95.5% sensitivity and 91.7% specificity) compared with 0.558 for routine MRI (63.6% sensitivity and 47.9% specificity) (P < .001).DWI has a higher diagnostic value for recurrent NPC than MRI. DWI can increase the diagnosis sensitivity and specificity of locally recurrent NPC.

Robustness versus disease differentiation when varying parameter settings in radiomics features: application to nasopharyngeal PET/CT

OBJECTIVES

To investigate the impact of parameter settings as used for the generation of radiomics features on their robustness and disease differentiation (nasopharyngeal carcinoma (NPC) versus chronic nasopharyngitis (CN) in FDG PET/CT imaging).

METHODS

We studied 106 patients (69/37 NPC/CN, pathology confirmed), and extracted 57 radiomics features under different parameter settings. Robustness was assessed by the intra-class correlation coefficient (ICC). Logistic regression with leave-one-out cross validation was used to generate classification probabilities, and diagnostic performance was assessed by the area under the receiver operating characteristic curve (AUC).

RESULTS

Varying averaging strategies and symmetry, 4/26 GLCM features showed poor range of pairwise ICCs of 0.02-0.98, while depicting good AUCs of 0.82-0.91. Varying distances, 5/26 GLCM features showed ICCs of 0.82-0.99 while corresponding AUCs were 0.52-0.91. 6/13 GLRLM features showed both high AUC (0.81-0.89) and high ICC (0.85-0.99) regarding to averaging strategies. 7/13 GLSZM features showed AUCs of 0.81-0.90 while having ICCs of 0.01-0.99 under different neighbourhoods. 2/5 NGTDM features showed AUCs of 0.81-0.85 while having ICCs of 0.19-0.89 for different window sizes. Differentiating a subset of NPC (stages I-II) form CN, both SumEntropy and SZLGE achieved significantly higher AUCs than metabolically active tumour volume (AUC: 0.91 vs. 0.72, p<0.01).

CONCLUSIONS

Radiomics features depicting poor absolute-scale robustness regarding to parameter settings can still lead to good diagnostic performance. As such, robustness of radiomics features should not be overemphasized for removal of features towards assessment of clinical tasks. For differentiating NPC from CN, some radiomics features (e.g. SumEntropy, SZLGE, LGZE) outperformed conventional metrics.

KEY POINTS

• Poor robustness did not necessarily translate into poor differentiation performance. • Absolute-scale robustness of radiomics features should not be overemphasized. • Radiomics features SumEntropy, SZLGE and LGZE outperformed conventional metrics.

Clinical utility of simultaneous whole-body 18F-FDG PET/MRI as a single-step imaging modality in the staging of primary nasopharyngeal carcinoma

PURPOSE

Both head and neck magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) play a crucial role in the staging of primary nasopharyngeal carcinoma (NPC). In this study, we sought to prospectively investigate the clinical utility of simultaneous whole-body 18F-FDG PET/MRI for primary staging of NPC patients.

METHODS

We examined 113 patients with histologically confirmed NPC who underwent pretreatment, simultaneous whole-body PET/MRI and PET/CT for primary tumor staging. The images obtained with the different imaging modalities were interpreted independently and compared with each other.

RESULTS

PET/MRI increased the accuracy of head and neck MRI for assessment of primary tumor extent in four patients via addition of FDG uptake information to increase the conspicuity of morphologically subtle lesions. PET/MR images were more discernible than PET/CT images for mapping tumor extension, especially intracranial invasion. Regarding the N staging assessment, the sensitivity of PET/MRI (99.5%) was higher than that of head and neck MRI (94.2%) and PET/CT (90.9%). PET/MRI was particularly useful for distinguishing retropharyngeal nodal metastasis from adjacent nasopharyngeal tumors. For distant metastasis evaluation, PET/MRI exhibited a similar sensitivity (90% vs. 86.7% vs. 83.3%), but higher positive predictive value (93.1% vs. 78.8% vs. 83.3%) than whole-body MRI and PET/CT, respectively.

CONCLUSIONS

For tumor staging of NPC, simultaneous whole-body PET/MRI was more accurate than head and neck MRI and PET/CT, and may serve as a single-step staging modality.

Contribution of 18F-FDG PET/CT to Staging of Head and Neck Malignancies

OBJECTIVES

Accurate staging of head and neck cancer (HNC) plays an important role in patient management as well as protection of functional characteristics of the head and neck region. Our aim was to investigate the contribution of 2-[¹⁸F]-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography/computed tomography (PET/CT) as part of HNC staging to clinical evaluation and treatment planning.

METHODS

Clinical records of 138 HNC cases who has undergone ¹⁸F-FDG PET/CT imaging were retrospectively reviewed. Sixty-five cases who had accessible clinical follow-up data were included in the study group, and their PET/CT and conventional imaging findings were evaluated.

RESULTS

In the case group with a PET/CT and magnetic resonance imaging (MRI) for evaluation of primary lesion the sensitivity rates for PET/CT and MRI were calculated as 91.3% and 82.6%, the positive predictive values (PPV) as 91.3% and 82.6%, specificity as 71.4% and 42.8%, and the negative predictive value (NPV) as 71.4% and 42.8%, respectively. In terms of metastatic lymph node evaluation, the sensitivity was calculated as 100% and 88.8%, the NPV as 100% and 83.3%, respectively. The PPV and specificity was 100% for both modalities. In the case group with CT for primary lesion evaluation, the sensitivity and PPV were found as 95.2% and 100% for PET/CT, and as 85.7% and 94.7% for CT, respectively. in metastatic lymph node evaluation, the sensitivity was found as 100% for PET/CT and 50% for CT, and the PPV, specificity and NPV were determined as 100% for both methods. PET/CT findings resulted in a change in 'tumor, node, metastasis' staging in 5 cases.

CONCLUSIONS

PET/CT in HNC contributes to staging, thus playing a role in treatment planning, especially in patients with locally advanced disease.

Prognostic value of maximum standard uptake value, metabolic tumor volume, and total lesion glycolysis of positron emission tomography/computed tomography in patients with nasopharyngeal carcinoma: A systematic review and meta-analysis

BACKGROUND

The maximal standard uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of positron emission tomography/computed tomography (PET/CT) in patients with nasopharyngeal carcinoma (NPC) perform as new prognostic factors, but the outcomes of the published articles were inconclusive. In this meta-analysis, we evaluated the prognostic value of SUVmax, MTV, and TLG of PET/CT in patients with NPC.

METHODS

Relevant English articles were searched in PubMed and EMBASE. The data of patients and the survival outcomes were extracted. Pooled hazard ratios (HRs) were accounted to assess the prognostic value of the SUVmax, MTV, and TLG.

RESULTS

This meta-analysis combined 10 primary studies including 941 patients with NPC. The combined HRs (95% confidence interval [CI] of higher SUVmax, higher MTV, and higher TLG for event-free survival were 2.33 (95% CI, 1.39-3.91, P = .001), 2.51 (95% CI, 1.61-3.91, P < .0001), and 2.74 (95% CI, 1.91-3.93, P < .00001), respectively. Regarding overall survival, the combined HRs were 2.50 (95%CI, 1.65-3.78, P < .0001) with higher SUVmax, 3.30 (95% CI, 1.92-5.69, P < .0001) with higher MTV and 3.18 (95% CI, 1.70-5.96, P = .0003) with higher TLG.

CONCLUSION

SUVmax, MTV, and TLG were significant prognostic predictors in patients with NPC. And the results suggested that higher SUVmax, MTV, and TLG were associated with worse prognosis.

Comparison of 18FDG PET/PET-CT and bone scintigraphy for detecting bone metastases in patients with nasopharyngeal cancer: a meta-analysis

OBJECTIVE

We performed a meta-analysis to compare the diagnostic efficacy of ¹⁸FDG PET/PET-CT and bone scintigraphy (BS) for diagnosing bone metastatic cancers in nasopharyngeal cancer patients.

RESULTS

6 studies (1238 patients) fulfilled the inclusion criteria. The pooled sensitivities for ¹⁸FDG PET/PET-CT and BS were 0.81 (95% confidence interval [CI] = 0.70 to 0.98) and 0.39 (95% CI = 0.26 to 0.54), specificities were 0.99 (95% CI = 0.98 to 0.99) and 0.98 (95% CI = 0.96 to 0.99), and the areas under curve were 0.98 (95% CI = 0.97 to 0.99) and 0.84 (95% CI = 0.81 to 0.87).

MATERIALS AND METHODS

Several databases were searched for all available articles. We calculated the sensitivities, specificities, diagnostic odds ratios, likelihood ratios, and area under summary receiver operating characteristic curves for ¹⁸FDG PET/PET-CT and BS, respectively.

CONCLUSIONS

¹⁸FDG PET/PET-CT is superior to BS for diagnosing bone metastases in nasopharyngeal cancer patients.¹⁸FDG PET/PET-CT may enhance the diagnosis of bone metastases and provide more accurate information for the optimal management of nasopharyngeal cancer.

Temporal Subtraction of Serial CT Images with Large Deformation Diffeomorphic Metric Mapping in the Identification of Bone Metastases

Purpose To determine the improvement of radiologist efficiency and performance in the detection of bone metastases at serial follow-up computed tomography (CT) by using a temporal subtraction (TS) technique based on an advanced nonrigid image registration algorithm. Materials and Methods This retrospective study was approved by the institutional review board, and informed consent was waived. CT image pairs (previous and current scans of the torso) in 60 patients with cancer (primary lesion location: prostate, n = 14; breast, n = 16; lung, n = 20; liver, n = 10) were included. These consisted of 30 positive cases with a total of 65 bone metastases depicted only on current images and confirmed by two radiologists who had access to additional imaging examinations and clinical courses and 30 matched negative control cases (no bone metastases). Previous CT images were semiautomatically registered to current CT images by the algorithm, and TS images were created. Seven radiologists independently interpreted CT image pairs to identify newly developed bone metastases without and with TS images with an interval of at least 30 days. Jackknife free-response receiver operating characteristics (JAFROC) analysis was conducted to assess observer performance. Reading time was recorded, and usefulness was evaluated with subjective scores of 1-5, with 5 being extremely useful and 1 being useless. Significance of these values was tested with the Wilcoxon signed-rank test. Results The subtraction images depicted various types of bone metastases (osteolytic, n = 28; osteoblastic, n = 26; mixed osteolytic and blastic, n = 11) as temporal changes. The average reading time was significantly reduced (384.3 vs 286.8 seconds; Wilcoxon signed rank test, P = .028). The average figure-of-merit value increased from 0.758 to 0.835; however, this difference was not significant (JAFROC analysis, P = .092). The subjective usefulness survey response showed a median score of 5 for use of the technique (range, 3-5). Conclusion TS images obtained from serial CT scans using nonrigid registration successfully depicted newly developed bone metastases and showed promise for their efficient detection. ^© RSNA, 2017 Online supplemental material is available for this article.

[PET-CT in head and neck cancer]

The importance of ¹⁸F-fluorodesoxyglucose positron-emission tomography (FDG-PET) for the diagnosis of malignant disease is increasing. On one hand, this is due to the high sensitivity of this method, on the other, because the entire body can be examined. FDG-PET can be particularly advantageous for the diagnosis of head and neck tumors, where tumor staging is an important prognostic parameter and essentially determines the therapeutic regimen. This article presents the different possibilities for combined evaluation with PET and computed tomography (CT) for the diagnosis of patients with head and neck cancer. Special focus is placed on primary staging and tumor follow-up, as well as on the role of PET-CT in the diagnosis of patients with cancer of unknown primary origin (CUP). The use of PET-CT for radiotherapy planning and new aspects of PET technology are also discussed.

Optimal Modality for Detecting Distant Metastasis in Primary Nasopharyngeal Carcinoma during Initial Staging: A Systemic Review and Meta-analysis of 1774 Patients

Purpose: To compare the diagnostic performance of two modalities commonly used for detecting distant metastasis in primary nasopharyngeal carcinoma (NPC): 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) and conventional work-ups (CWUs). Methods: All topic-related studies were comprehensively searched and included. We determined sensitivities and specificities across studies, calculated negative and positive likelihood ratios (LR- and LR+, respectively), and constructed summary receiver operating characteristic curves. Moreover, we compared the diagnostic performance of PET/CT and CWUs by analyzing studies that reported the results of these diagnostic methods on the same patients. Results: The pooled sensitivity and specificity were 85.7% and 98.1% for PET/CT (1474 patients), and 38.0% and 97.6% for CWUs (1329 patients). In the head-to-head comparison of PET/CT and CWUs (1029 patients), PET/CT showed a significantly higher sensitivity (83.7% vs. 40.1%, P < 0.001) and lower LR- (0.169 vs. 0.633, P < 0.001) than CWUs on a per-patient basis; no significant difference was observed in pooled specificity (97.7% vs. 97.8%, P = 0.892) or LR+ (36.416 vs. 16.845, P = 0.149). The superiority of PET/CT over CWUs was due mainly to the better diagnostic performance on bone metastasis. However, suboptimal sensitivity of PET/CT was reported in the aspect of detection of liver metastasis. Sensitivity analyses showed relatively poor sensitivity and LR- of PET/CT compared to the original analysis. Conclusions: PET/CT was superior to CWUs in detecting distant metastasis in primary NPC. However, the efficacy of PET/CT in detecting liver metastasis still requires further optimization.