18F-FDG-PET for evaluation of the response to concurrent chemoradiation therapy with intensity-modulated radiation technique for Stage T4 nasopharyngeal carcinoma

Volumetric parameters derived from FLT-PET performed at completion of treatment predict efficacy of Carbon-ion Radiotherapy in patients with locally recurrent Nasopharyngeal Carcinoma

The purpose of this study was to investigate the role of 3'-deoxy-3'-[¹⁸F]fluorothymidine (FLT)-PET for predicting the outcome of patients with locally recurrent nasopharyngeal carcinoma (LR-NPC) treated by carbon-ion radiotherapy (CIRT). Patients received FLT-PET/CT scan one-week prior to or after completion of CIRT were enrolled in the study. All patients were from prospective trials or treated using a standardized protocol. Time-dependent receiver operator characteristics (ROC) were used to determine the optimal cutoff values for FLT-PET parameters. Univariable and multivariable analyses of local progression-free survival (LPFS) were performed using Cox regression, to examine the prognostic value of FLT-PET parameters, including SUV_max, metabolic tumor volume (MTV) and total lesion thymidine (TLT). A total of 41 patients were enrolled. Elevated MTV and TLT were significantly associated with worse LPFS, in both univariable and multivariable analyses. ROC analysis revealed that both an MTV value higher than 8.6 and a TLT value higher than 14.9 were predictive of increased risk of developing local recurrence, the adjusted HRs were 5.59 (p=0.009) and 7.76 (p=0.002), respectively. In conclusion, FLT-PET was found to be a promising prognostic tool for LR-NPC patients and might play a role in the treatment guidance.

Clinical significance of the post-radiotherapy 18F-fludeoxyglucose positron emission tomography response in nasopharyngeal carcinoma

Objective:

The aim of the present study was to evaluate the clinical significance of the post-radiotherapy ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) response for detecting residual disease and predicting survival outcome in patients with nasopharyngeal cancer.

Methods:

We reviewed 143 patients with nasopharyngeal cancer who underwent ¹⁸F-FDG PET within 6 months after completion of radiotherapy between 2001 and 2012. ¹⁸F-FDG PET findings at the primary tumor (T–) and regional lymph nodes (N–) were separately assessed and considered negative [PET (–)] or positive [PET (+)] depending on the remaining focal increased uptake of ¹⁸F-FDG that was greater than that of the surrounding muscle or blood vessels. The standard of reference was histopathological confirmation or clinical/imaging follow-up. Overall survival (OS), distant metastasis-free survival (DMFS), and locoregional recurrence-free survival (LRRFS) rates were estimated from the date of the start of radiotherapy.

Results:

The median follow-up period was 73 months (range, 9–182 months). Overall, 83 and 66% of patients achieved T–PET (-) and N–PET (-) responses, and the negative-predictive values (NPVs) for T– and N– were 100 and 99%, respectively. The sensitivity, specificity, and positive-predictive value were 100, 84, and 8% for T–, and 67, 80, and 7% for N–, respectively. The 5-year OS, DMFS, and LRRFS rates were 83, 83, and 87%, respectively, and patients with N–PET (+) with SUV_max >2.5 showed significantly inferior 5-year OS and DMFS rates than patients with N–PET (-) or N–PET (+) with SUV_max ≤2.5 (44 vs 86%, p = 0.004; 36 vs 85%, p < 0.001).

Conclusion:

In patients that have received definitive (chemo)radiotherapy for nasopharyngeal cancer, ¹⁸F-FDG PET within 6 months of completion of treatment has a high NPV for predicting residual disease and is prognostic for long-term treatment outcomes. Patients with remaining focal increased uptake of ¹⁸F-FDG at lymph nodes may benefit from more aggressive treatments, and further studies are needed to validate the clinical significance of post-radiotherapy ¹⁸F-FDG PET.

Advances in knowledge:

We found that post-radiotherapy ¹⁸F-FDG PET findings have a high NPV for detecting residual disease and are a significant prognostic factor for treatment outcomes.

Prospective evaluation of plasma Epstein-Barr virus DNA clearance and fluorodeoxyglucose positron emission scan in assessing early response to chemotherapy in patients with advanced or recurrent nasopharyngeal carcinoma

BACKGROUND

Plasma Epstein-Barr virus (pEBV) DNA and fluorodeoxyglucose positron emission (PET) reflect tumour burden in advanced NPC. This study hypothesised that a dual endpoint based on assessing pEBV DNA clearance and PET response could predict early drug response.

METHODS

Eligible patients underwent a computed tomography (CT) scan and dual PET-CT at baseline, a PET-CT at 4 weeks, and then a CT scan at 10 weeks after starting palliative or induction chemotherapy. Plasma EBV DNA clearance was determined.

RESULTS

Fifty-eight out of 70 enrolled patients completed all imaging and 50/58 had falling pEBV DNA level, which allowed calculation of the clearance. At a median follow-up of 29.1 months, the dual endpoint (pEBV DNA clearance ≤ 10 days and > 50% drop in sum of SUVmax of target lesions) was an independent indicator of overall survival (hazard ratio (HR) = 0.135, 95% CI = 0.039 to 0.466, p = 0.0015) and progression-free survival (HR = 0.136, 95% CI = 0.048 to 0.385, p = 0002). This dual endpoint could predict subsequent response by Response Evaluation Criteria In Solid Tumours (RECIST) criteria at 10 weeks after chemotherapy.

CONCLUSIONS

Early PET-CT response and pEBV DNA clearance could predict survival and subsequent response. This dual endpoint is an innovative tool for assessing early drug response.

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.

Investigational drugs for nasopharyngeal carcinoma

INTRODUCTION

Nasopharyngeal carcinoma (NPC) is endemic to Southern China and Asia and is etiologically associated with the Epstein Barr virus (EBV). Whole exome and genome sequencing (WES, WGS) studies of NPC have reported several actionable therapeutic targets, and that the mutational load of NPC maybe comparable to that of squamous head and neck cancer. These unique biological characteristics have been exploited as potential targets and a wide range of investigational drugs are being investigated in clinical trials. Area covered: This review focused on the latest clinical development of the most promising classes of investigational agents in the treatment of advanced NPC. These include inhibitors of tumor angiogenesis, kinase signaling pathways and immunotherapy. Expert opinion: Checkpoint inhibitors and EBV-specific T-cell therapy have shown promising activity in early phase clinical trials, and are being further evaluated in randomized studies. For patients whose tumors express genetic alterations that are known to predict response to kinase inhibitors, novel trial designs such as an 'Umbrella' study may be considered given the abundance of targeted agents that are now available for clinical evaluation. It is envisioned that regulatory approval for new drugs for advanced NPC will occur in the near future.

Detecting Residual/Recurrent Head Neck Squamous Cell Carcinomas Using PET or PET/CT: Systematic Review and Meta-analysis

OBJECTIVE

To evaluate the diagnostic accuracy of positron emission tomography (PET) and PET/computed tomography (CT) for detecting residual and/or recurrent local and regional disease and distant metastases in patients with head and neck squamous cell carcinomas (HNSCCs) following radiotherapy with or without chemotherapy.

DATA SOURCES

A systematic review with no language restrictions was conducted using PREMEDLINE, MEDLINE, EMBASE, and Google Scholar.

REVIEW METHODS

Only prospective studies with histopathological and/or clinical follow-up that assessed the diagnostic accuracy of PET and PET/CT in detecting residual and/or recurrent disease following radiotherapy with or without chemotherapy in patients with HNSCCs were included.

RESULTS

Twenty-seven studies were identified. The pooled sensitivity and specificity of PET and PET/CT for detecting residual or recurrent disease at the primary site was 86.2% and 82.3%, respectively. For residual and recurrent neck disease, the sensitivity and specificity were 72.3% and 88.3%, while for distant metastases, the values were 84.6% and 94.9%.

CONCLUSIONS

PET and PET/CT are highly accurate in detecting residual and/or recurrent HNSCC. PET/CT is more specific than PET alone. Specificity is also greater for scans performed more than 12 weeks after radiotherapy with or without chemotherapy. The authors support the use of PET/CT after 12 weeks posttreatment for the assessment of residual or recurrent disease.

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 (VOL_SUV40) 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, VOL_SUV40, and VOL_Ki37 (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 VOL_SUV40 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.

Use of PET in Head and Neck Cancers

Head and neck cancer imaging is especially necessary for staging. Computed tomography and magnetic resonance imaging are the techniques frequently used for this purpose. These methods are valuable for displaying detailed anatomical structures; however, they may be inadequate for making the distinction between recurrence, residual tumor, fibrosis, and normal tissues with an altered anatomy after treatments such as surgery, radiotherapy, and chemotherapy and for the detection of metastases. From this point, positron emission tomography may be a promising imaging method. Scanning the entire body with a single method is an important advantage of positron emission tomography. It may be useful in the detection of synchronous tumors, which are a serious problem in head and neck cancers. Positron emission tomography may provide additional contribution for neck metastases, where the primary site is unknown and is undetectable by other imaging techniques.

Different prognostic values of plasma Epstein-Barr virus DNA and maximal standardized uptake value of 18F-FDG PET/CT for nasopharyngeal carcinoma patients with recurrence

PURPOSE

To evaluate and compare the prognostic value of Epstein-Barr virus (EBV) DNA and maximal standard uptake values (SUVmax ) of 18F-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG-PET) in subgroups of nasopharyngeal carcinoma (NPC) patients with locoregional or distant recurrence.

PATIENTS AND METHODS

A total of 194 patients with recurrent NPC (locoregional recurrence: 107, distant recurrence: 87) were enrolled. Patients took evidence of recurrence performed with 18F-FDG-PET and an EBV DNA test before salvage treatment. Clinical parameters, the status of EBV DNA and the value of SUVmax were used for survival analysis using the Kaplan-Meier method and the Cox proportional hazards regression model.

RESULTS

In the subgroup of patients with locoregional recurrence, patients with SUVmax<8.65 had significantly better overall survival (OS) (P=0.005) compared with the patients with SUVmax ≥8.65. However, both elevated EBV DNA load (≥21,100 copies/ml) and distant SUVmax (≥13.55) were significantly associated with worse OS compared with the patients with EBV DNA <21,100 copies/ml or distant SUVmax <13.55 for the subgroup with distant recurrence (P=0.015 and P=0.006, respectively). The predictive ability of EBV DNA was superior to that of SUVmax (P=0.062). Multivariate analysis showed that SUVmax was only an independent prognostic factor for OS in patients with locoregional recurrence (P=0.042), whereas EBV DNA independently predicted OS for the patients with distant recurrence (P=0.007). For those patients with undetectable EBV DNA, SUVmax<8.65 was still an independent favorable prognostic factor (P=0.038).

CONCLUSIONS

SUVmax is a useful biomarker for predicting OS in nasopharyngeal carcinoma patients with locoregional recurrence or with undetectable EBV DNA. Both distant SUVmax and EBV DNA appear to be independent predictors of OS in patients with distant recurrence; however, the predictive ability of EBV DNA was superior to that of SUVmax.

The Predictive Value of Pretreatment 18-F-FDG-PET-CT in Locally Advanced Nasopharyngeal Cancer Patients Treated Definitively with Induction Chemotherapy Followed by Concurrent Chemo-Radiotherapy

Aims

This study aimed to evaluate the role of pretreatment 18F-Fluorodeoxyglucose positron emission tomography (¹⁸F-FDG-PET-CT) as a predictor of disease-free survival (DFS), and overall survival (OS) in locally advanced nasopharyngeal carcinoma (LANPC) patients treated definitively with docetaxel-based induction chemotherapy followed by concurrent chemoradiation (CRT).

Materials and methods

This is a retrospective study approved by the institutional review board and included LANC patients treated definitively and consecutively between January 2008 and December 2012 with induction chemotherapy; docetaxel, cisplatin, and 5-flurouracil (TPF) followed by CRT utilizing weekly cisplatin. All patients had baseline pretreatment ¹⁸F-FDG-PET-CT. We studied the association between the baseline primary tumor maximum standardized uptake value (SUVmax) and the treatment outcomes; OS and DFS.

Results

The study included 70 eligible LANPC patients. The 4-year OS and DFS rates were 86.7% and 78.6%, respectively. The median OS and DFS intervals were not reached. On a univariate analysis, the 4-years DFS was significantly higher in patients with pretreatment SUVmax <8 compared versus ≥ 8 (95% vs 57.7%, P=0.002). Furthermore, DFS was significantly correlated with pretreatment T stage (P=0.01), N stage (P=0.02), treatment response (P<0.001) and treatment breaks (P<0.001). On a multivariate analysis, the SUVmax category was the only factor correlated with 4-year DFS (Hazard ratio=10.2, 95% C I 1.3-116.8, P=0.035) but not OS (P=0.085).

Disclosure statement

There is no actual or potential conflict of interest with the production and publication of this work. No author has a direct or indirect commercial financial incentive associated with the publication of this article.

Conclusion

This study shows that the pretreatment primary tumor ¹⁸F-FDG-PET-CT SUVmax is a potential independent prognostic predictor of clinical outcomes in patients with LANC treated definitively with TPF induction chemotherapy followed by CRT. Further controlled clinical trials are worthwhile.

FDG-PET/CT imaging biomarkers in head and neck squamous cell carcinoma

This article discusses the value of ¹⁸F-fluoro-2-deoxyglucose PET/CT imaging biomarkers in head and neck squamous cell carcinoma. ¹⁸F-fluoro-2-deoxyglucose PET/CT is valuable at baseline staging, radiotherapy planning, therapy response assessment and in the follow-up of patients with head and neck squamous cell carcinoma. Maximum and peak standardized uptake value (SUV_max and SUV_peak), metabolic tumor volume and total lesion glycolysis are the common ¹⁸F-fluoro-2-deoxyglucose quantitative parameters that have been studied, along with qualitative assessments. These parameters will be evaluated with respect to their established or potential role as noninvasive biomarkers for patient risk stratification, treatment response and survival outcome.

Evidence-based guideline recommendations on the use of positron emission tomography imaging in head and neck cancer

AIMS

To provide evidence-based practice guideline recommendations on the use of fluoro-2-deoxy-D-glucose positron emission tomography (PET) for diagnosis, staging and assessing treatment response, restaging or recurrence of head and neck cancer.

MATERIALS AND METHODS

A systematic review by Facey et al. (Health Technology Assessment 2007;11(44):iii-iv, xi-267) was used as the evidence base for recommendation development. As the review was limited to August 2005, the evidence base was updated to July 2011 using the same search strategies for MEDLINE and EMBASE used in the original review. The authors of the current systematic review drafted recommendations, which were reviewed, adapted and accepted by consensus by the Ontario provincial Head and Neck Disease Site Group and a special meeting of clinical experts.

RESULTS

The results of the Facey et al. review for head and neck cancer included five other systematic reviews and 31 primary studies. The 2005 to 2011 update search included four additional systematic reviews and 53 primary studies. Recommendations were developed based on this evidence and accepted by consensus.

CONCLUSIONS

PET is recommended in the M and bilateral nodal staging of all patients with head and neck squamous cell carcinoma where conventional imaging is equivocal, or where treatment may be significantly modified. PET is recommended in all patients after conventional imaging and in addition to, or prior to, diagnostic panendoscopy where the primary site is unknown. PET is recommended for the staging and assessment of recurrence of patients with nasopharyngeal carcinoma if conventional imaging is equivocal. PET is recommended for restaging patients who are being considered for major salvage treatment, including neck dissection.

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.

Biological response of nasopharyngeal carcinoma to radiation therapy: a pilot study using serial 18F-FDG PET/CT scans

We used serial (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) to evaluate tumors' maximum standardized uptake value (SUV(max)) before, during, and after radiotherapy to explore the biological behavior of and response to radiation therapy in various subtypes of nasopharyngeal carcinoma (NPC). Sixty-one patients with pathologically diagnosed NPC were prospectively enrolled into the study. WHO type II(B) disease had a higher initial SUV(max) and more significant biological response at the primary site as compared with type II(A) subtype. The two subtypes of WHO type II NPC may significantly differ in their biological behavior and response to radiotherapy.

PET/CT for staging and follow-up of pediatric nasopharyngeal carcinoma

PURPOSE

While FDG PET/CT for the evaluation of nasopharyngeal carcinoma (NPC) in adult patients has documented advantages and disadvantages compared with conventional imaging, to our knowledge, no studies of FDG PET/CT for the evaluation of NPC in pediatric patients have been performed. In this investigation, we studied the utility of FDG PET/CT in children with NPC.

METHODS

The study group comprised 18 children with biopsy-proven NPC who underwent FDG PET/CT and MRI (total 38 pairs of images). All baseline and follow-up FDG PET/CT and MRI studies were independently reviewed for restaging of disease.

RESULTS

The concordance between FDG PET/CT and MRI in T, N, and overall staging was 29%, 64%, and 43%, respectively. Compared with MRI, FDG PET/CT yielded lower T and overall staging and showed less cervical and retropharyngeal lymphadenopathy. The concordance between follow-up FDG PET/CT and MRI was 79% overall and 100% 9 months after therapy. In patients who achieved complete remission, FDG PET/CT showed disease clearance 3-6 months earlier than MRI. There were no false-positive or false-negative FDG PET/CT scans during follow-up.

CONCLUSION

FDG PET/CT may underestimate tumor extent and regional lymphadenopathy compared with MRI at the time of diagnosis, but it helps to detect metastases and clarify ambiguous findings. FDG PET/CT is sensitive and specific for follow-up and enables earlier determination of disease remission. FDG PET/CT is a valuable imaging modality for the evaluation and monitoring of NPC in pediatric patients.

Detection of mucosal recurrent nasopharyngeal carcinomas after radiotherapy with narrow-band imaging endoscopy

PURPOSE

This study evaluated the feasibility of screening mucosal recurrent nasopharyngeal carcinoma with narrow-band imaging (NBI) endoscopy.

METHODS AND MATERIALS

One hundred and six patients were enrolled. All patients underwent conventional white-light (WL) endoscopic examination of the nasopharynx followed by NBI endoscopy. Biopsies were performed if recurrence was suspected.

RESULTS

We identified 32 suspected lesions by endoscopy in WL and/or NBI mode. Scattered brown spots (BS) were identified in 22 patients, and 4 of the 22 who had negative MRI findings were histopathologically confirmed to be neoplasias that were successfully removed via endoscopy. A comparison of the visualization in NBI closer view corresponded to histopathological findings in 22 BS, and the prevalence rates of neoplasias in tail signs, round signs, and irregularities signs were 0% (0/6), 0% (0/7), and 44.4% (4/9), respectively (p = 0.048). The sensitivity, specificity, and diagnostic capability were 37.5%, 92.9% and 0.652 for WL, 87.5%, 74.5% and 0.810 for NBI, and 87.5%, 87.8%, and 0.876 for NBI closer view, respectively. NBI closer view was effective in increasing specificity compared with NBI alone (87.8% vs. 74.5%, p < 0.05), and in increasing sensitivity and diagnostic capability compared to WL alone (87.5% vs. 37.5%, p < 0.05; 0.876 vs. 0.652, p = 0.0001).

CONCLUSIONS

Although NBI in endoscopy can improve sensitivity of mucosal recurrent nasopharyngeal neoplasias, false-positive (nonneoplasia BS) results may be obtained in areas with nonspecific inflammatory changes due to postradiation effects. NBI closer view not only can offer a timely, convenient, and highly reliable assessment of mucosal recurrent nasopharyngeal carcinoma, it can also make endoscopic removal possible.

Role of Positron Emission Tomography-Computed Tomography in Head and Neck Cancer

Head and neck squamous cell carcinoma (HNC) is the sixth most common cancer worldwide. In the United States, it accounts for approximately 2% of all cancers and 2% of cancer deaths. The introduction of integrated positron emission tomography and computed tomography (PET/CT) has revolutionized imaging by permitting improved and more accurate anatomic localization of functional abnormalities in the complex territory of the head and neck region, and PET/CT has become a standard clinical imaging modality in patients with HNC. The main indications for PET/CT in HNC are in pretherapy staging, detection of unknown primaries, and monitoring of therapy response or disease surveillance. Although PET/CT is a promising tool in diagnosis and surveillance of HNC, there is lack of consensus as to its use, accuracy, and implications for patient management. The existing literature on the role of PET/CT in the management of HNC is reviewed, and a summary of the current debate is provided. Second primary cancers are the main cause of death among HNC patients with early disease, and the presence of distant metastases greatly impairs the survival of patients with advanced HNC. Therefore, early detection of second primary and metastatic tumors is imperative for optimizing survival outcome. However, given the lack of randomized, prospective trials addressing the role of PET/CT after chemoradiotherapy, the ideal function of PET/CT in disease surveillance has yet to be defined.

Diagnostic performance of post-treatment FDG PET or FDG PET/CT imaging in head and neck cancer: a systematic review and meta-analysis

PURPOSE

Our objective was to conduct a systematic review and meta-analysis of studies assessing the diagnostic performance of (18)F-fluorodeoxyglucose positron emission tomography (FDG PET) with or without computed tomography (CT) in post-treatment response assessment and/or surveillance imaging of head and neck squamous cell carcinoma (HNSCC).

METHODS

A systematic search of the indexed medical literature was done using appropriate keywords to identify relevant studies. Metrics of diagnostic test accuracy, viz. sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were extracted from individual studies and combined using a random effects model to yield weighted mean pooled estimates with 95% confidence intervals (95% CI). The impact of timing of post-treatment scan, study quality and advancements in PET technology was explored through meta-regression.

RESULTS

A total of 51 studies involving 2,335 patients were included in the meta-analysis. The weighted mean (95% CI) pooled sensitivity, specificity, PPV and NPV of post-treatment FDG PET(CT) for the primary site was 79.9% (73.7-85.2%), 87.5% (85.2-89.5%), 58.6% (52.6-64.5%) and 95.1% (93.5-96.5%), respectively. Similar estimates for the neck were 72.7% (66.6-78.2%), 87.6% (85.7-89.3%), 52.1% (46.6-57.6%) and 94.5% (93.1-95.7%), respectively. Scans done ≥ 12 weeks after completion of definitive therapy had moderately higher diagnostic accuracy on meta-regression analysis using time as a covariate.

CONCLUSION

The overall diagnostic performance of post-treatment FDG PET(CT) for response assessment and surveillance imaging of HNSCC is good, but its PPV is somewhat suboptimal. Its NPV remains exceptionally high and a negative post-treatment scan is highly suggestive of absence of viable disease that can guide therapeutic decision-making. Timing of post-treatment imaging has a significant, though moderate impact on diagnostic accuracy.

Plasma Epstein-Barr virus DNA screening followed by ¹⁸F-fluoro-2-deoxy-D-glucose positron emission tomography in detecting posttreatment failures of nasopharyngeal carcinoma

BACKGROUND

The authors investigated the clinical implication of plasma Epstein-Barr virus (EBV) DNA assay and (18) F-fluoro-2-deoxy-D-glucose ((18) F-FDG) positron emission tomography (PET) in the detection of recurrent nasopharyngeal carcinoma (NPC).

METHODS

Two hundred forty-five patients with NPC who had previously received treatment and were in a state of remission were monitored prospectively using a plasma EBV DNA assay every 3 to 6 months. (18) F-FDG PET studies were obtained when abnormal EBV DNA or clinically suggestive signs of recurrence were noted.

RESULTS

Thirty-six of 245 patients (14.7%) patients had abnormal EBV DNA tests and underwent PET scans. In the remaining 209 patients, 3658 blood tests were negative. PET scans also were obtained in 5 patients who had undetectable EBV DNA levels but signs that were clinically suggestive of disease recurrence. Subsequent analyses focused on 41 patients who had PET studies. In lesion-based analyses, the sensitivity, specificity, and accuracy of PET by visual interpretation were 81.8%, 77.1%, and 79.2%, respectively, for all 125 lesions. In patient-based analyses, the accuracy of PET by visual interpretation was 51.2%. All 36 patients who had detectable plasma levels of EBV DNA had demonstrable NPC recurrences, whereas no recurrences were noted in 5 patients who had undetectable EBV DNA levels but signs that clinically mimicked a recurrence. Compared with annual PET, the annual cost of blood tests every 3 to 6 months per patient saved approximately 77% ∼ 88% in expenses.

CONCLUSIONS

The plasma EBV DNA assay correctly predicted all NPC recurrences, and PET had high capacity to localize potential lesion sites. The authors concluded that applying the strategy of EBV DNA screening followed by PET scanning may guide appropriate further treatment planning in a cost-effective manner.

18F-FDG PET or PET-CT to evaluate prognosis for head and neck cancer: a meta-analysis

PURPOSE

The purpose of this meta-analysis was to evaluate the prognostic value of standard uptake value (SUV) from serial Fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) in patients with head and neck cancer.

METHODS

We searched for articles limited to head and neck cancer, dealt with the impact of SUV on survival and published in English. The endpoints were disease-free survival (DFS), overall survival (OS), and local control (LC). Two reviewers extracted data independently.

RESULTS

Thirty-five studies were identified; of which, 26 studies involving 1,415 patients met the inclusion criteria. Pooled survival data suggested better DFS, OS, and LC in patients with low SUV of pre-treatment, and the odds ratio (OR) was 0.23, 0.24, and 0.27, respectively. Patients having tumors with low SUV of post-treatment also had significantly better DFS (OR = 0.17) and OS (OR = 0.28) than those with high SUV.

CONCLUSIONS

The present meta-analysis showed that (18)F-FDG uptake, as measured by the SUV before treatment and metabolic response after treatment, are valuable for predicting long-term survival in head and neck cancer. High (18)F-FDG uptake may be useful for identifying patients requiring more aggressive treatment.

Nasopharyngeal carcinoma: the next challenges

Nasopharyngeal carcinoma (NPC) differs from other head and neck cancers in its aetiology, epidemiology and potential therapeutic options. Despite cure for the majority of the patients, challenges still exist in the prevention of disease relapse, treatment of patients with refractory or metastatic NPC and the management of long-term toxicities. This article discusses the specific challenges in pushing the boundaries of NPC treatments further, with an emphasis on prognostic/predictive markers, molecularly targeted therapies, immunotherapies and the areas of interest with regard to long-term toxicities arising from therapeutic interventions.

Preoperative [18F]FDG PET/CT maximum standardized uptake value predicts recurrence of uterine cervical cancer

PURPOSE

To determine if preoperative [(18)F]FDG-PET/CT imaging has prognostic significance in patients with uterine cervical cancer.

METHODS

Patients with FIGO stage IB to IIA cervical cancer were imaged with integrated FDG PET/CT before radical surgery. The relationship between the maximum standardized uptake value (SUV(max)) of FDG in the primary tumour during PET/CT and recurrence was examined.

RESULTS

Included in the study were 75 patients. Medical records including clinical data, treatment modalities, and treatment results were retrospectively reviewed. The median duration of follow-up was 13 months (range 3 to 58 months) after treatment. Median preoperative SUV(max) values in the primary tumours were significantly higher in patients with higher FIGO stages (p = 0.0149), pelvic lymph node metastasis (p = 0.0068), parametrial involvement (p = 0.0002), large (>4 cm) tumour size (p = 0.0022), presence of lymphovascular space invasion (p = 0.0055), and deep cervical stromal invasion (p < 0.0001). In univariate analysis, lymph node metastasis, parametrial invasion, presence of lymphovascular space invasion, and preoperative SUV(max) (uncategorized values) in the primary tumour were significantly associated with recurrence. However, in multivariate analysis, preoperative SUV(max) (p = 0.014, HR 1.178, 95% CI 1.034-1.342), age (p = 0.021, HR 0.87, 95% CI 0.772-0.980), and parametrial involvement (p = 0.040, HR 27.974, 95% CI 1.156-677.043) by primary tumour were significantly associated with recurrence.

CONCLUSION

Preoperative FDG uptake by the primary tumour showed a significant association with recurrence in patients with uterine cervical cancer.

Update on the management and therapeutic monitoring of advanced nasopharyngeal cancer

Despite being potentially curable at an early stage, more than 50% of patients who have nasopharyngeal carcinoma present with advanced locoregional disease, which results in a poor prognosis. This article discusses key advancements in the management of nasopharyngeal cancer, including the incorporation of concurrent chemoradiotherapy, new radiotherapy delivery techniques in the form of conformal and intensity-modulated radiotherapy, and salvage options for locoregional recurrence. New cytotoxic and targeted therapies that have resulted in improved survival in the metastatic setting are also described. The use of Epstein-Barr virus DNA for the prognostication and monitoring of nasopharyngeal cancer and the role of new diagnostic imaging techniques are also discussed.

Biologically conformal treatment: biomarkers and functional imaging in radiation oncology

'Conformal radiation therapy' is the standard of care in radiation oncology, referring to the process of shaping the radiation beam to precisely match a tumor's physical dimensions. We describe 'biologically conformal radiotherapy', in which the radiation oncologist matches the prescribed treatment to a tumor's biological characteristics and the host's predicted tolerance of radiation. This paradigm emphasizes that not all tumors are equally sensitive to radiation; conversely, some patients are especially susceptible to radiation's side effects. Patients bearing radioresistant tumors or those prone to toxicity may be best treated with the incorporation of targeted radiation modulators or, in extreme cases, by a different modality. The biological characteristics of tumors can be assessed by a wide range of techniques: functional imaging (positron emission tomography and advanced magnetic resonance imaging), single gene/protein molecular techniques and 'omic' technologies. This paper reviews the latest advances in the use of biomarkers and functional imaging in guiding patients to receive the most appropriate treatment.

PET Imaging of Skull Base Neoplasms

The utility of 18-F-fluorodeoxyglucose-positron emission tomography (PET) and PET/CT for the evaluation of skull base tumors is incompletely investigated, as a limited number of studies specifically focus on this region with regard to PET imaging. Several patterns can be ascertained, however, by synthesizing the data from various published reports and cases of primary skull base malignancies, as well as head and neck malignancies that extend secondarily to the skull base, including nasopharyngeal carcinoma, nasal cavity and paranasal sinus tumors, parotid cancers, and orbital tumors.