Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography imaging in patients with carcinoma of the nasopharynx: diagnostic accuracy and impact on clinical management

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.

High Pretreatment Platelet-to-Albumin Ratio Predicts Poor Survival Results in Locally Advanced Nasopharyngeal Cancers Treated with Chemoradiotherapy

PURPOSE

In a lack of similar research, we assessed the prognostic utility of pretreatment platelet-to-albumin ratio (PAR) in locally advanced nasopharyngeal carcinoma (LANPC) patients managed with concurrent chemoradiotherapy (CCRT).

PATIENTS AND METHODS

Present retrospective analysis included a sum of 128 consecutively treated LANPC patients who underwent cisplatinum-based radical CCRT. Availability of an ideal pretreatment PAR cutoff that may stratify the study population into two cohorts with significantly distinct survival outcomes was sought by utilizing the receiver operating characteristic (ROC) curve analysis. The primary and secondary endpoints were overall survival (OS) and progression-free survival (PFS), respectively.

RESULTS

A rounded 5.2 [area under the curve (AUC): 68.9%; sensitivity: 67.4%; and specificity: 65.2%] value was identified as the ideal PAR cutoff that grouped patients into two gatherings [PAR≥5.2 (N=60) versus <5.2 (N=68)]. The median follow-up duration was 86.4 months (range: 9-147). Kaplan-Meier comparisons between the two PAR groups revealed significantly diminished median PFS (69.4 versus 106.8 months for PAR<5.2; P< 0.012) and OS (88.3 versus not reached yet for PAR<5.2; P= 0.023) for the PAR ≥ 5.2 group. The results of multivariate analyses affirmed the pretreatment PAR≥5.2 as an independent prognostic factor that indicates diminished PFS (P= 0.016) and OS (P= 0.019) together with the respective N2-3 nodal stage (versus N0-1; P<0.05 for PFS and OS, respectively) and weight loss >5% at past six months (≤5%; P<0.05 for PFS and OS, respectively).

CONCLUSION

The results of the current retrospective analysis provided a robust and independent adverse prognostic value for pretreatment PAR ≥ 5.2 in terms of median and long-term PFS and OS outcomes in LA-NPC patients this patient group treated with conclusive CCRT.

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.

Baseline Low Prognostic Nutritional Index Predicts Poor Survival in Locally Advanced Nasopharyngeal Carcinomas Treated With Radical Concurrent Chemoradiotherapy

BACKGROUND

To retrospectively assess the impact of prognostic nutritional index (PNI) on survival outcomes of patients with locoregionally advanced nasopharyngeal carcinoma (LA-NPC) treated with concurrent chemoradiotherapy (CCRT).

METHODS

This study incorporated 154 patients with LA-NPC who received exclusive cisplatinum-based CCRT. Receiver operating characteristic (ROC) curve analysis was utilized for accessibility of pretreatment PNI cutoffs influencing survival results. The primary end point was the interaction between the overall survival (OS) and PNI values, while cancer-specific survival (CSS) locoregional progression-free survival (LR-PFS), distant metastasis-free survival (DMFS), and PFS were the secondary end points.

RESULTS

A rounded PNI cutoff value of 51 was identified in ROC curve analyses to exhibit significant link with CSS, OS, DMFS, and PFS outcomes, but not LR-PFS. Patients grouping per PNI value (≥51 [N = 95] vs <51 [N = 49]) revealed that PNI < 51 group had significantly shorter median CSS (P < .001), OS (P < .001), DMFS (P < .001), and PFS (P < .001) times than the PNI ≥ 51 group, and the multivariate results confirmed the PNI < 51 as an independent predictor of poor outcomes for each end point (P < .05 for each). The unfavorable impact of the low PNI was also continued at 10-year time point with survival rates of 77.9% versus 42.4%, 73.6% versus 33.9%, 57.9% versus 27.1%, and 52.6% versus 23.7% for CSS, OS, DMFS, and PFS, respectively. Additionally, we found that PNI < 51 was significantly associated with higher rates of weight loss >5% over past 6 months (49.2% versus 11.6%; P = .002) compared to PNI < 51 group.

CONCLUSION

Low pre-CCRT PNI levels were independently associated with significantly reduced CSS, OS, DMFS, and PFS outcomes in patients with LA-NPC treated with definitive CCRT.

Prognostic Value of Deep Learning PET/CT-Based Radiomics: Potential Role for Future Individual Induction Chemotherapy in Advanced Nasopharyngeal Carcinoma

PURPOSE

We aimed to evaluate the value of deep learning on positron emission tomography with computed tomography (PET/CT)-based radiomics for individual induction chemotherapy (IC) in advanced nasopharyngeal carcinoma (NPC).

EXPERIMENTAL DESIGN

We constructed radiomics signatures and nomogram for predicting disease-free survival (DFS) based on the extracted features from PET and CT images in a training set (n = 470), and then validated it on a test set (n = 237). Harrell's concordance indices (C-index) and time-independent receiver operating characteristic (ROC) analysis were applied to evaluate the discriminatory ability of radiomics nomogram, and compare radiomics signatures with plasma Epstein-Barr virus (EBV) DNA.

RESULTS

A total of 18 features were selected to construct CT-based and PET-based signatures, which were significantly associated with DFS (P < 0.001). Using these signatures, we proposed a radiomics nomogram with a C-index of 0.754 [95% confidence interval (95% CI), 0.709-0.800] in the training set and 0.722 (95% CI, 0.652-0.792) in the test set. Consequently, 206 (29.1%) patients were stratified as high-risk group and the other 501 (70.9%) as low-risk group by the radiomics nomogram, and the corresponding 5-year DFS rates were 50.1% and 87.6%, respectively (P < 0.0001). High-risk patients could benefit from IC while the low-risk could not. Moreover, radiomics nomogram performed significantly better than the EBV DNA-based model (C-index: 0.754 vs. 0.675 in the training set and 0.722 vs. 0.671 in the test set) in risk stratification and guiding IC.

CONCLUSIONS

Deep learning PET/CT-based radiomics could serve as a reliable and powerful tool for prognosis prediction and may act as a potential indicator for individual IC in advanced NPC.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

(18)F-FDG Uptake Characteristics in Differentiating Benign from Malignant Nasopharyngeal Lesions in Children

The characteristics of FDG uptake in the physiologic and malignant nasopharynx were investigated in the paper which was correlated with either pathologic findings or clinical follow-up. Three patients had pathologically established nasopharyngeal malignancy. In the 3 nasopharyngeal malignancies, 2 had diffusely and expansively increased FDG uptake, and one had asymmetric uptake. Our results indicated that the difference between adenoid hypertrophy and malignancy is asymmetric or diffusely expansive ¹⁸F-FDG uptake with or without correlating morphologic lesion on diagnostic CT in children under 10 years of age. The typical characteristics of physiologic and inflammatory ¹⁸F-FDG uptake in nasopharynx are symmetrically trapezoid. Diffusely increased nasopharyngeal FDG uptake can be considered physiologic if SUV_max is less than 7.6 but should be carefully assessed by pharyngorhinoscopy if SUV_max is greater than 11 and there is no correlating morphologic lesion on diagnostic CT. The diffusely, expansively increased uptake, and asymmetric uptake in particular, should be considered as malignancy. Further biopsy is especially indicated in patients with retropharyngeal space and bilateral cervical lymph node abnormality but no history of malignancy.

Prospective Study of Tailoring Whole-Body Dual-Modality [18F]Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography With Plasma Epstein-Barr Virus DNA for Detecting Distant Metastasis in Endemic Nasopharyngeal Carcinoma at Initial Staging

Purpose

To evaluate which patients with nasopharyngeal carcinoma (NPC) obtained the greatest benefits from the detection of distant metastasis with [18F]fluorodeoxyglucose positron emission tomography and computed tomography (PET/CT) combined with plasma Epstein-Barr virus (EBV) DNA levels.

Patients and Methods

Consecutive patients with NPC were prospectively enrolled. PET/CT, conventional work-up (CWU), and quantification of plasma EBV DNA were performed before treatment. The accuracy of these strategies for distant metastases was assessed. The costs of the diagnostic strategies were compared.

Results

Eighty-six (14.8%) of the 583 eligible patients were found to have distant metastases; 71 patients (82.6%) by PET/CT and 31 patients (36.0%) by CWU. In the multivariable analysis, advanced N stage (odds ratio, 2.689; 95% CI, 1.894 to 3.818) and pretreatment EBV DNA level (odds ratio, 3.344; 95% CI, 1.825 to 6.126) were significant risk factors for distant metastases. PET/CT was not superior to CWU for detecting distant metastases in very low–risk patients (N0-1 with EBV DNA < 4,000 copies/mL; P = .062), but was superior for the low-risk patients (N0-1 with EBV DNA ≥ 4,000 copies/mL and N2-3 with EBV DNA < 4,000 copies/mL; P = .039) and intermediate-risk patients (N2-3 disease with EBV DNA ≥ 4,000 copies/mL; P < .001). The corresponding patient management changes based on PET/CT were 2.9%, 6.3%, and 16.5%, respectively. The costs per true-positive case detected by PET/CT among these groups were ¥324,138 (≈$47,458), ¥96,907 (≈$14,188), and ¥34,182 (≈$5,005), respectively.

Conclusion

PET/CT detects more distant metastases than conventional staging in patients with NPC. The largest benefit in terms of cost and patient management was observed in the subgroup with N2-3 disease and EBV DNA ≥ 4,000 copies/mL.

Improving target definition for head and neck radiotherapy: a place for magnetic resonance imaging and 18-fluoride fluorodeoxyglucose positron emission tomography?

Defining the target for head and neck radiotherapy is a critical issue with the introduction of steep dose gradients associated with intensity-modulated radiotherapy. Tumour delineation inaccuracies are a major source of error in radiotherapy planning. The integration of 18-fluoride fluorodeoxyglucose positron emission tomography ((18)FDG-PET) and magnetic resonance imaging directly into the radiotherapy planning process has the potential to greatly improve target identification/selection and delineation. This raises a range of new issues surrounding image co-registration, delineation methodology and the use of functional data and treatment adaptation. This overview will discuss the practical aspects of integrating (18)FDG-PET and magnetic resonance imaging into head and neck radiotherapy planning.

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.

(18)FDG-PET/CT for detecting distant metastases and second primary cancers in patients with head and neck cancer. A meta-analysis

We performed a meta-analysis to evaluate the role of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)FDG-PET/CT) in detecting distant metastases and second primary cancers in patients with head and neck cancer (HNC) at staging. Studies about (18)FDG-PET/CT for detecting distant metastases and second primary cancers in patients with HNC were systematically searched in the MEDLINE, EMBASE, and EBM Review databases from January 1, 2000 to March 1, 2011. A software called "Meta-DiSc" was used to obtain pooled estimates of sensitivity, specificity, diagnostic odds ratios, summary receiver operating characteristic curves, and Q* index. Twelve articles fulfilled all inclusion criteria. The pooled sensitivity, specificity, and Q* index estimates with 95% confidence interval for PET/CT were 0.888 (0.827-0.928), 0.951 (0.936-0.963), and 0.937 (0.844-0.964). Subgroup analysis showed similar pooled estimates of sensitivity, specificity, and Q* index for initial staging and restaging, nasopharyngeal cancer and all other sites of HNC. (18)FDG-PET/CT has good diagnostic performance in detecting distant metastases and second primary cancers in patients with HNC.

Accuracy of whole-body PET and PET-CT in initial M staging of head and neck cancer: a meta-analysis

BACKGROUND

A meta-analysis was conducted to evaluate the accuracy of whole-body positron emission tomography (PET) and PET-CT in initial M staging of head and neck cancer.

METHODS

After a systematic review of English language studies, sensitivity, specificity, and other measures of whole-body PET and PET-CT were pooled. Summary receiver operating characteristic (SROC) curves were also used to summarize overall test performance.

RESULTS

Eight PET and 7 PET-CT studies were identified. The pooled sensitivity estimates for PET and PET-CT were 0.848 (95% confidence interval [CI], 0.776-0.905) and 0.875 (95% CI, 0.787-0.936). The pooled specificity estimates were 0.952 (95% CI, 0.933-0.967) and 0.950 (95% CI, 0.931-0.964). The Q* index estimates for PET-CT (0.9409) were not significantly higher than for PET (0.9154; p > .05).

CONCLUSION

Whole-body PET and PET-CT have good diagnostic performance in initial M staging of head and neck cancer; although PET-CT tends to have higher accuracy than PET.

Nasopharyngeal carcinoma detected by narrow-band imaging endoscopy

The aim of the study was to investigate the novel endoscopic findings in nasopharyngeal carcinoma (NPC) under narrow-band imaging (NBI) and to determine the reliability of screening NPC by NBI. A total of 79 adults underwent nasopharyngeal biopsy. We proposed five distinctly different findings that need to be examined by NBI: Type I: brownish spots, Type II: irregular microvascular pattern (IMVP), Type III: light crests, Type IV: side-difference, Type V: presence of either IMVP or side-difference, of which last three (Type III-V) were a new concept. The results of NPC diagnosis by detecting NBI Type V pattern, the false positive, false negative, sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 6.7%, 2.9%, 97.1%, 93.3%, 91.7%, 97.7%, and 94.9%, respectively. On the other hand, there was a higher prevalence of Type I and IV patterns in T1 category NPC. The nasopharyngeal endoscopy coupled with NBI was able to provide a rapid, convenient, and highly reliable screening for high-risk populations.

Preliminary study of 11C-choline PET/CT for T staging of locally advanced nasopharyngeal carcinoma: comparison with 18F-FDG PET/CT

Evaluation of nasopharyngeal carcinoma (NPC) using (18)F-FDG PET/CT is limited by the intense physiologic uptake of (18)F-FDG in the brain. We attempted to improve detection of intracranial tumor invasion (including better delineation of invasion near the skull base) in locally advanced NPC using(11)C-choline PET/CT.

METHODS

Fifteen patients with newly diagnosed or recurrent locally advanced NPC were enrolled in the study. (18)F-FDG and (11)C-choline PET/CT was performed on all patients. PET/CT images obtained using the 2 tracers were compared using both maximum standardized uptake value (SUVmax) and tumor-to-brain (T/B) ratios. All patients were followed up for more than 1 y.

RESULTS

The sensitivity of (18)F-FDG PET/CT in detecting locally advanced NPC was 86.6%, compared with a 100% sensitivity for (11)C-choline PET/CT (t = 2.143, P = 0.483). The SUVmax of lesions detected was higher using (18)F-FDG than using (11)C-choline (12.81 ± 5.00 vs. 6.84 ± 2.76, t = 6.416, P < 0.001), but the T/B ratio was much higher for (11)C-choline than for (18)F-FDG (18.62 ± 7.95 vs. 1.38 ± 0.59, t = 8.801, P < 0.001). Compared with (18)F-FDG PET/CT, (11)C-choline PET/CT improved the delineation of intracranial invasion in 6 of 12 patients (χ(2) = 8.00, P = 0.014), skull base invasion in 4 of 14 patients, and orbital invasion in 3 of 3 patients.

CONCLUSION

(11)C-choline can improve the quality of PET/CT in the T staging of NPC.

Nasopharyngeal carcinoma: relationship between 18F-FDG PET-CT maximum standardized uptake value, metabolic tumour volume and total lesion glycolysis and TNM classification

PURPOSE

We aimed to evaluate the relationships between primary tumour; maximum standardized uptake value (SUVmax), metabolic tumour volume (TV) and total lesion glycolysis (TLG) and tumour-node metastases (TNM) classification in nasopharyngeal carcinoma (NPC) patients.

METHODS

Fluorine-18 fluorodeoxyglucose positron emission tomography-computed tomography scans of 57 consecutive newly diagnosed NPC patients (age range, 15-80 years) were retrospectively reviewed. SUVmax, TV and TLG were recorded. Two-tailed Spearman's correlation was used to analyse the relationships between the metabolic parameters and the TNM staging system.

RESULTS

Positive correlations were observed between SUVmax (P<0.001, R=0.516), TV (P<0.001, R=0.504) and TLG (P<0.001, R=0.620) and T-stage, and both TV and SUVmax were independent variables that significantly affected T-stage (P<0.001, adjusted R=0.370). No other significant correlations were found between the metabolic parameters and TNM classification system.

CONCLUSION

The metabolic parameters derived from fluorine-18 fluorodeoxyglucose positron emission tomography-computed tomography were positively correlated with T-stage in primary NPC. Our findings may suggest a complementary role of these parameters to TNM staging in prognostication of NPC patients.

Hybrid imaging (SPECT/CT and PET/CT): improving therapeutic decisions

The incremental diagnostic value of integrated positron emission tomography-computed tomography (PET/CT) or single-photon emission computed tomography (SPECT)/CT images compared with PET or SPECT alone, or PET or SPECT correlated with a CT obtained at a different time includes the following: (1) improvement in lesion detection on both CT and PET or SPECT images, (2) improvement in the localization of foci of uptake resulting in better differentiation of physiological from pathologic uptake, (3) precise localization of the malignant foci, for example, in the skeleton vs soft tissue or liver vs adjacent bowel or node (4) characterization of serendipitous lesions, and (5) confirmation of small, subtle, or unusual lesions. The use of these techniques can occur at the time of initial diagnosis, in assessing the early response of disease to treatment, at the conclusion of treatment, and in continuing follow-up of patients. PET/CT and SPECT/CT fusion images affect the clinical management in a significant proportion of patients with a wide range of diseases by (1) guiding further procedures, (2) excluding the need of further procedures, (3) changing both inter- and intramodality therapy, including soon after treatment has been initiated, and (4) by providing prognostic information. PET/CT fusion images have the potential to provide important information to guide the biopsy of a mass to active regions of the tumor and to provide better maps than CT alone to modulate field and dose of radiation therapy. It is expected that the role of PET/CT and SPECT/CT in changing management will continue to evolve in the future and that these tools will be fundamental components of the truly "personalized medicine" we are striving to deliver.

Imaging of Nasopharyngeal Carcinoma

Nasopharyngeal cancer (NPC) is a unique disease that shows clinical behaviour, epidemiology and histopathology that is different from that of other squamous cell carcinomas of the head and neck. Magnetic resonance imaging (MRI) is now the preferred imaging modality in the assessment and staging of NPC, especially in relation to its superior soft tissue contrast, ability to demonstrate perineural tumour spread, parapharyngeal space, bone marrow involvement and its ability to show the involvement of adjacent structures, such as the adjacent paranasal sinuses and intracranial extension. An understanding of its patterns of spread and the criteria used in the AJCC TNM staging system is important to relay the relevant information to the referring clinician, so that appropriate treatment planning decisions may be made. In this article, the various features of NPC that are pertinent to staging and treatment planning will be discussed, inclusive of locoregional spread, nodal involvement and metastatic disease. Key words: Magnetic resonance imaging, Staging

Clinical Applications of FDG PET and PET/CT in Head and Neck Cancer

18F-FDG PET plays an increasing role in diagnosis and management planning of head and neck cancer. Hybrid PET/CT has promoted the field of molecular imaging in head and neck cancer. This modality is particular relevant in the head and neck region, given the complex anatomy and variable physiologic FDG uptake patterns. The vast majority of 18F-FDG PET and PET/CT applications in head and neck cancer related to head and neck squamous cell carcinoma. Clinical applications of 18F-FDG PET and PET/CT in head and neck cancer include diagnosis of distant metastases, identification of synchronous 2nd primaries, detection of carcinoma of unknown primary and detection of residual or recurrent disease. Emerging applications are precise delineation of the tumor volume for radiation treatment planning, monitoring treatment, and providing prognostic information. The clinical role of 18F-FDG PET/CT in N0 disease is limited which is in line with findings of other imaging modalities. MRI is usually used for T staging with an intense discussion concerning the preferable imaging modality for regional lymph node staging as PET/CT, MRI, and multi-slice spiral CT are all improving rapidly. Is this review, we summarize recent literature on 18F-FDG PET and PET/CT imaging of head and neck cancer.

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.

Staging of untreated nasopharyngeal carcinoma with PET/CT: comparison with conventional imaging work-up

PURPOSE

We prospectively compared PET/CT and conventional imaging for initial staging of nasopharyngeal carcinoma (NPC).

METHODS

A total of 111 patients with histologically proven NPC were investigated with PET/CT and conventional imaging (head-and-neck MRI, chest X-ray, abdominal ultrasound, and bone scan) before treatment. The respective findings were reviewed independently and then compared with each other.

RESULTS

With regard to T staging, PET/CT showed a discrepancy with head-and-neck MRI in 36 (32.4%) of the study subjects. With regard to N staging, PET/CT showed a discrepancy with head-and-neck MRI in 15 (13.5%) patients. Among the discordant cases, MRI was superior in demonstrating tumor involvement in the parapharyngeal space, skull base, intracranial area, sphenoid sinus, and retropharyngeal nodes while PET/CT was superior in demonstrating neck nodal metastasis. PET/CT disclosed 13 of 16 patients with distant malignancy compared with four patients disclosed by conventional imaging work-up. The false-positive rate of PET/CT was 18.8%. PET/CT correctly modified M staging in eight patients (7.2%) and disclosed a second primary lung malignancy in one patient (0.9%).

CONCLUSION

In NPC patients, MRI appears to be superior to PET/CT for the assessment of locoregional invasion and retropharyngeal nodal metastasis. PET/CT is more accurate than MRI for determining cervical nodal metastasis and should be the better reference for the neck status. PET/CT has an acceptable diagnostic yield and a low false-positive rate for the detection of distant malignancy and can replace conventional work-up to this aim. PET/CT and head-and-neck MRI are suggested for the initial staging of NPC patients.

Advances in nasopharyngeal carcinoma

PURPOSE OF REVIEW

Nasopharyngeal carcinoma prognosis is related to its potential locoregional invasion and metastatic spread. Among prognostic factors, initial tumor-node-metastasis stage is the main one, besides other biological parameters. Worldwide development of positron emission tomography imaging is changing modalities of staging. Concomitant chemoradiotherapy represents one of the most recent advances in the treatment of nasopharyngeal carcinoma patients, besides intensity-modulated radiation therapy. This review updates these recent advances in diagnosis and treatment of nasopharyngeal carcinoma.

RECENT FINDINGS

Recent publications have shown the superiority of fused positron emission tomography/computed tomography over positron emission tomography alone and conventional imaging to do an accurate staging and to impact on patient management. Circulating Epstein-Barr virus DNA load may be a useful prognostic marker in endemic regions. Recent meta-analysis confirmed the superiority of concurrent chemoradiotherapy to radiotherapy alone. Previous publications have shown that induction chemotherapy with new agents might be promising. Data demonstrating targeted therapies efficacy in metastatic nasopharyngeal carcinoma are limited to date.

SUMMARY

Positron emission tomography-computed tomography is replacing conventional imaging in the initial M staging of nasopharyngeal carcinoma. Its usefulness in response evaluation after therapy and its place in the follow-up need to be prospectively evaluated. Cisplatin-based concomitant chemoradiotherapy is now the standard treatment for locally advanced patients. However, incidence of relapses remains high, and new multimodal therapy is needed.