Prognostic impact of primary tumor volume in patients with nasopharyngeal carcinoma treated by definitive radiation therapy

Patterns of failure in patients with nasopharyngeal cancer of Northeastern region of India: a retrospective observational study

PURPOSE

We aimed to analyze patterns of failure and disease volume-treatment outcomes in patients with Nasopharyngeal carcinoma (NPC) treated with definitive radiation with or without concurrent chemotherapy at a tertiary cancer centre in northeast India.

METHODS

From February 2018 to February 2022, 99 histopathologically proved non-metastatic NPC patients treated with curative-intent RT with or without chemotherapy were retrospectively analyzed. Locally advanced patients received neoadjuvant or adjuvant chemotherapy. The Cox proportional hazards model was used to investigate the impact of various prognostic factors on locoregional free survival (LRFS), distant metastasis free survival (DMFS), progression free survival (PFS) and overall survival (OS). The log-rank test and Kaplan-Meir curves compared outcome variables based on ROC analysis-classified tumor volume.

RESULTS

During a median follow up of 25.4 months (17.3-39.2), 35(35.4%) patients developed recurrence. Twenty-three patients developed locoregional failures, of which 11 were in-field; 12 patient showed an out-field failure. The 3-year LRFS, DMFS, PFS and OS was 71.10%, 70.90%, 64.10% and 74.10% respectively. There was statistically significant difference in LRFS according to T staging (p < 0.0001). Gross tumor volume (GTVp) and gross nodal volume (GTVn) were an independent prognostic factor for OS, PFS, LRFS and DMFS. The cut-off volumes for GTVp and GTVn for distant metastases and locoregional failure, respectively, were found to be 13 and 22.7 mL and 3.7 and 39.2 mL, respectively, by ROC curve analysis. Based on this, 99 patients were divided into three subgroups. OS demonstrated significant differences among patients in different volume subgroups for GTVp (p = 0.03) and GTVn (p = 0.00024).

CONCLUSIONS

For NPC patients who undergo curative IMRT, primary tumour and nodal volumes are independent prognostic indicators. GTVp and GTVn are highly predictive of local control, distant metastases, disease-free survival, and overall survival. This justifies their use as quantitative prognostic indicator for NPC.

Significance of radiologic extranodal extension in locoregionally advanced nasopharyngeal carcinoma with lymph node metastasis: a comprehensive nomogram

OBJECTIVE

We aimed to assess the significance of rENE and creat a predictive tool (nomogram) for estimating Overall Survival (OS) in locoregionally advanced Nasopharyngeal Carcinoma (NPC) patients with Lymph Node Metastasis (LNM) based on their clinical characteristics and Radiologic Extranodal Extension (rENE).

METHODS

Five hundred and sixty-nine NPC patients with LNM were randomly divided into training and validation groups. Significant factors were identified using univariate and multivariate analyses in the training cohort. Then, the nomogram based on the screening results was established to predict the Overall Survival (OS). Calibration curves and the Concordance index (C-index) gauged predictive accuracy and discrimination. Receiver Operating Characteristic (ROC) analysis assessed risk stratification, and clinical utility was measured using Decision Curve Analysis (DCA). The nomogram's performance was validated for discrimination and calibration in an independent validation cohort.

RESULTS

A total of 360 (63.2%) patients were present with radiologic extranodal extension at initial diagnosis. Patients with rENE had significantly lower OS than other patients. Multivariate analysis identified the five factors, including rENE, for the nomogram model. The C-index was 0.75 (0.71-0.78) in the training cohort and 0.76 (0.69-0.83) in the validation cohort. Notably, the nomogram outperformed the 8th TNM staging system, as evident from the higher AUC values (0.77 vs. 0.60 for 2year and 0.75 vs. 0.65 for 3year) and well-calibrated calibration curves. Decision curve analysis indicated improved Net Benefit (NB) with the nomogram for predicting OS. The log-rank test confirmed significant survival distinctions between risk groups in both training and validation cohorts.

CONCLUSIONS

We demonstrated the prognostic value of rENE in nasopharyngeal carcinoma and developed a nomogram based on rENE and other factors to provide individual prediction of OS for locoregionally advanced nasopharyngeal carcinoma with lymph node metastasis.

LEVEL OF EVIDENCE

III.

Efficacy and safety of a treatment in patients with locoregionally advanced nasopharyngeal carcinoma (LANC) involving carotid artery invasion

PURPOSE

Locally advanced nasopharyngeal carcinoma (LANC) often invades the parapharyngeal space and internal carotid artery. Are patients with LANC invading carotid artery are at risk of massive neck hemorrhage after radiotherapy?

METHODS

This retrospective study included 130 LANC patients with carotid artery invasion admitted to our hospital between January 2012 and September 2019. All patients were treated with induction chemotherapy followed by concurrent chemoradiotherapy (CCRT) ± epidermal growth factor receptor (EGFR) inhibitor. Univariate and multivariate analysis of risk factors were conducted for the prognosis and the occurrence of massive neck hemorrhage of LANC patients with carotid artery invasion.

OUTCOMES

The 5-year progression-free survival (PFS), distant metastasis-free survival (DMFS), local nodal recurrence-free survival (LNRFS), local recurrence-free survival (LRFS), nodal recurrence-free survival (NRFS) and overall survival (OS) of the 130 patients were 75.2%, 76.8%, 90.0%, 93.9%, 95.8% and 87.2%, respectively. The incidence of fatal bleeding after radiotherapy was 2.3% (3/130). The primary site of the three cases were all the pharyngeal recess, with more than 270° carotid artery invasion, suffering nasopharyngeal necrosis after radiotherapy (2 of which were diabetics and 1 received re-radiation after recurrence). Univariate analysis showed that clinical stage was negatively correlated with DMFS and PFS (P < 0.05). The induction chemotherapy TP regimen, platinum-based concurrent chemotherapy and EGFR inhibitors (Nituzumab/Cetuximab) significantly improved PFS and DMFS (P < 0.05). Patients with hemoglobin levels > 110 g/L had significantly inferior PFS, DMFS and OS than those with hemoglobin levels ≤ 110 g/L (P < 0.05). Multivariate analysis showed that the EGFR inhibitor was an independent risk factor for PFS and DMFS, while the lowest hemoglobin level was an independent risk factor for OS.

CONCLUSIONS

In LANC patients whose carotid artery invasion was < 270°, induction chemotherapy (IC) followed by helical tomotherapy (HT) and concurrent chemoradiotherapy (CCRT) with EGFR (epidermal growth factor receptor) inhibitor had mild and tolerable side effects, better PFS and DMFS, with no massive hemorrhage. In patients whose primary tumor was pharyngeal recess with carotid artery invasion ≥ 270°, poorly controlled diabetes or re-radiotherapy led to a higher risk of massive hemorrhage after radiotherapy.

Establishment of a Prognostic Nomogram for Patients With Locoregionally Advanced Nasopharyngeal Carcinoma Incorporating TNM Stage, Post-Induction Chemotherapy Tumor Volume and Epstein-Barr Virus DNA Load

Objectives

To establish and validate an effective nomogram to predict clinical outcomes for patients with locoregionally advanced nasopharyngeal carcinoma (LA-NPC).

Materials and Methods

The clinicopathological parameters and follow-up information of 402 locoregionally advanced NPC patients (training cohort, n = 302; validation cohort, n = 100) were retrospectively enrolled. The nomogram was built with the important prognostic variables identified by Cox regression analysis. Overall survival (OS) and progression-free survival (PFS) were the primary and secondary endpoints, respectively. The predictive power and clinical utility of the nomogram were assessed using the Harrell concordance index (C-index), calibration curve, and decision curve analysis. We compared the eighth staging system model with the nomogram to analyze whether the model could improve the accuracy of prognosis

Results

Epstein–Barr virus (EBV) DNA load, the gross tumor volume (GTVnx), and cervical lymph node tumor volume (GTVnd) after induction chemotherapy were the independent predictors of OS and PFS. The calibration curves indicated superb agreement between the nomogram-predicted probabilities and observed actual probabilities of survival. The C-index and area under the receiver operator characteristic curve (AUC) of the nomogram integrating these significant factors and N stage, and TNM stage were higher than those of the eighth TNM system alone. In addition, the decision curve analyses demonstrated the clinical value and higher overall net benefit of the nomogram. High-risk groups identified by the nomogram had significantly poorer OS and PFS than the low-risk group (p < 0.05).

Conclusions

The multidimensional nomogram incorporating TNM stage, EBV DNA load, and tumor volume after induction chemotherapy led to a more precise prognostic prediction and could be helpful for stratifying risk and guiding treatment decisions in locoregionally advanced NPC patients who have undergone induction chemotherapy and concurrent chemoradiation.

An interpretable machine learning prognostic system for locoregionally advanced nasopharyngeal carcinoma based on tumor burden features

OBJECTIVES

We aimed to build a survival system by combining a highly-accurate machine learning (ML) model with explainable artificial intelligence (AI) techniques to predict distant metastasis in locoregionally advanced nasopharyngeal carcinoma (NPC) patients using magnetic resonance imaging (MRI)-based tumor burden features.

MATERIALS AND METHODS

1643 patients from three hospitals were enrolled according to set criteria. We employed ML to develop a survival model based on tumor burden signatures and all clinical factors. Shapley Additive exPlanations (SHAP) was utilized to explain prediction results and interpret the complex non-linear relationship among features and distant metastasis. We also constructed other models based on routinely used cancer stages, Epstein-Barr virus (EBV) DNA, or other clinical features for comparison. Concordance index (C-index), receiver operating curve (ROC) analysis and decision curve analysis (DCA) were executed to assess the effectiveness of the models.

RESULTS

Our proposed system consistently demonstrated promising performance across independent cohorts. The concordance indexes were 0.773, 0.766 and 0.760 in the training, internal validation and external validation sets. SHAP provided personalized protective and risk factors for each NPC patient and uncovered some novel non-linear relationships between features and distant metastasis. Furthermore, high-risk patients who received induction chemotherapy (ICT) and concurrent chemoradiotherapy (CCRT) had better 5-year distant metastasis-free survival (DMFS) than those who only received CCRT, whereas ICT + CCRT and CCRT had similar DMFS in low-risk patients.

CONCLUSIONS

The interpretable machine learning system demonstrated superior performance in predicting metastasis in locoregionally advanced NPC. High-risk patients might benefit from ICT.

Baseline MRI-Radiomics Can Predict Overall Survival in Non-Endemic EBV-Related Nasopharyngeal Carcinoma Patients

Advanced stage nasopharyngeal cancer (NPC) shows highly variable treatment outcomes, suggesting the need for independent prognostic factors. This study aims at developing a magnetic resonance imaging (MRI)-based radiomic signature as a prognostic marker for different clinical endpoints in NPC patients from non-endemic areas. A total 136 patients with advanced NPC and available MRI imaging (T1-weighted and T2-weighted) were selected. For each patient, 2144 radiomic features were extracted from the main tumor and largest lymph node. A multivariate Cox regression model was trained on a subset of features to obtain a radiomic signature for overall survival (OS), which was also applied for the prognosis of other clinical endpoints. Validation was performed using 10-fold cross-validation. The added prognostic value of the radiomic features to clinical features and volume was also evaluated. The radiomics-based signature had good prognostic power for OS and loco-regional recurrence-free survival (LRFS), with C-index of 0.68 and 0.72, respectively. In all the cases, the addition of radiomics to clinical features improved the prognostic performance. Radiomic features can provide independent prognostic information in NPC patients from non-endemic areas.

Prognostic and Treatment Guiding Significance of MRI-Based Tumor Burden Features and Nodal Necrosis in Nasopharyngeal Carcinoma

We aimed to develop a nomogram integrating MRI-based tumor burden features (MTBF), nodal necrosis, and some clinical factors to forecast the distant metastasis-free survival (DMFS) of patients suffering from non-metastatic nasopharyngeal carcinoma (NPC). A total of 1640 patients treated at Sun Yat-sen University Cancer Center (Guangzhou, China) from 2011 to 2016 were enrolled, among which 1148 and 492 patients were randomized to a training cohort and an internal validation cohort, respectively. Additionally, 200 and 257 patients were enrolled in the Foshan and Dongguan validation cohorts, respectively, which served as independent external validation cohorts. The MTBF were developed from the stepwise regression of six multidimensional tumor burden variables, based on which we developed a nomogram also integrating nodal necrosis and clinical features. This model divided the patients into high- and low-risk groups by an optimal cutoff. Compared with those of patients in the low-risk group, the DMFS [hazard ratio (HR): 4.76, 95% confidence interval (CI): 3.39–6.69; p < 0.0001], and progression-free survival (PFS; HR: 4.11, 95% CI: 3.13–5.39; p < 0.0001) of patients in the high-risk group were relatively poor. Furthermore, in the training cohort, the 3-year DMFS of high-risk patients who received induction chemotherapy (ICT) combined with concurrent chemoradiotherapy (CCRT) was better than that of those who were treated with CCRT alone (p = 0.0340), whereas low-risk patients who received ICT + CCRT had a similar DMFS to those who only received CCRT. The outcomes we obtained were all verified in the three validation cohorts. The survival model can be used as a reliable prognostic tool for NPC patients and is helpful to determine patients who will benefit from ICT.

Metastatic Patterns and Prognosis of de novo Metastatic Nasopharyngeal Carcinoma in the United States

OBJECTIVE

To evaluate the distant metastatic patterns and prognostic factors for overall survival (OS) and cancer-specific survival (CSS) in de novo metastatic nasopharyngeal carcinoma (mNPC) using the Surveillance, Epidemiology, and End Results (SEER) database.

METHODS

Patients with de novo mNPC who had been diagnosed between 2004 and 2016 were identified from the SEER database. Kaplan-Meier analysis was used to calculate OS and CSS. Log-rank tests were employed to measure survival variation among subgroups. Individual predictors of CSS and OS were examined using Cox proportional-hazards regression models in patients with de novo mNPC.

RESULTS

We evaluated 224 patients with de novo mNPC who matched our inclusion criteria. Three-year CSS and OS for the whole cohort was 29.8% and 27.9%, respectively. Univariate analysis indicated that CSS and OS were influenced by age, histology, radiotherapy, chemotherapy, and liver metastasis. Neither the number of metastatic sites nor their specific location in bone, lungs, distant lymph nodes or brain significantly affected CSS or OS. The aforementioned independent prognosticators continued to significantly influence survival following multivariate analysis. Taking distant metastasis without liver involvement as a reference, liver metastasis was associated significantly with shorter OS at a hazard ratio (HR) of 1.581 (P = .021) and CSS at a HR of 1.643 (P = .016). Older age, keratinizing squamous cell carcinoma, no chemotherapy, and no radiotherapy were also prognosticators for poor OS (P < .05). Similar results were documented for CSS (P < .05).

CONCLUSION

For patients with de novo mNPC, liver metastasis is an independent prognosticator for inferior CSS and OS.

LEVEL OF EVIDENCE

3a Laryngoscope, 131:E1130-E1138, 2021.

Selection of a high-level physician may help improve outcomes of nasopharyngeal carcinoma

BACKGROUND

To assess the relationship between the level of clinical radiation oncologist and the prognosis of patients with nasopharyngeal carcinoma (NPC). To our knowledge, no previous study has explicitly assessed the relationship with cancer prognosis and clinical radiation oncologists level. The effect of physicians on the prognosis has been entirely ignored.

METHODS

Clinical data were collected for 1140 patients with newly diagnosed NPC. Based on the 3-year overall survival, the treating physicians were classified into 3 grades: high-level group, medium-level group, and low-level group. Cox proportional hazards regression analysis was used to assess the independent significance of different prognostic factors. Propensity score matching (PSM) was used to minimize the influence of confounders so that difference in outcomes provides an unbiased estimate of the influence of physician. Interactive Risk Attributable Program (IRAP) was used to calculate the attribution risk of individual risk factors or a combination of multiple factors.

RESULTS

The 3-year OS in the high-level, medium-level, and low-level groups was 92.9%, 87.7%, and 83.5%, respectively (p = 0.003). After propensity score matching, the 3-year OS was 92.4%, 87.4%, and 82.9%, respectively (p = 0.004). IRAP was used to calculate the attribution risk of mortality risk. After multivariable adjustment, patient-related factors including tumor accounted for 90.02% [95% confidence interval (CI), 73.43-96.84%) and physician factors accounted for 17.66% (95% CI, 5.39-44.65%) of the mortalityrisk. All related factors, including patient-related factors and physician factors accounted for 92.02% (95% CI, 77.83-97.43%).

CONCLUSION

Our study demonstrated obvious differences in the prognosis of patients treated by various clinical radiation oncologists. The largest share of prognosis risk was found to be at the patient level, while variation in prognosis was, in part, attributable to differences among physicians.

Prognostic value of nasopharynx tumour volume in local-regional advanced nasopharyngeal carcinoma

Background

To investigate the prognostic value of pretreatment primary gross tumor with (GTVp) and without retropharyngeal lymph nodes (GTVnx) for predicting survival outcomes in patients with local-regional advanced nasopharyngeal carcinoma (NPC) after intensity-modulated radiation therapy (IMRT).

Methods

From Jan 2012 to Dec 2017, 148 patients with local-regional advanced NPC who had undergone definitive radiotherapy were identified. GTVnx volume and retropharyngeal lymph nodes (GTVrLNs) volume were measured based on registration of MRI with contrast-enhanced CT images. The Kaplan-Meier method was used for survival analysis. Univariate and multivariate prognostic analyses was performed by using the Cox proportional hazard model. Receiver operating characteristic (ROC) curves were used to identify the cut-off point and assess the prognostic value for GTVnx, GTVp and GTVrLNs.

Results

The median follow-up time for the entire group was 27 months (ranging 7 to 80 months). The 3-year overall survival (OS) rate was 85%, and the 3-year local failure-free rate (LFFR), distant failure-free rate (DFFR) and disease-free survival (DFS) rates were 93%, 81%, and 73%, respectively. A positive correlation between GTVnx or GTVp volume and T stage was observed (both P<0.001). The 3-year LFFR, OS, and DFS rate, but not for DMFS, in NPC patients with GTVnx ≤42.7 cm³ was significantly better than those with >42.7 cm³ (all P<0.05). Multivariate analysis indicated that GTVnx volume (P=0.041) was the only independent prognostic factor for LFFR, while age and AJCC stage were two independent prognostic factors for OS.

Conclusions

The GTVnx is an independent prognostic factor for local control, while the prognostic value of GTVrLNs is limited. Physicians are recommended to distinguish between GTVnx and retropharyngeal lymph nodes (RLN) involvement when assessing the risk for local recurrence in advanced NPC.

The Role of Post-Neoadjuvant Chemotherapy Tumor Volume for Prognostication and Treatment Guidance in Loco-Regionally Advanced Nasopharyngeal Carcinoma

The value of post-neoadjuvant chemotherapy (NACT) tumor volume for prognostication in loco-regionally advanced nasopharyngeal carcinoma (LA-NPC) is unascertained. Here, we recruited 4109 histologically proven LA-NPC (stage III-IVA) that were treated with radical chemo-intensive-modulated radiotherapy (IMRT). Post-NACT gross primary tumor (GTVp) and lymph node (GTVnd) volumes of each patient were calculated from planning computed tomography (CT). We observed similar linear association between GTVp/GTVnd and overall survival (OS); thresholds of 52 cm³ for GTVp and 12 cm³ for GTVnd were consistent for risk discretization for OS, disease-free survival (DFS), distant metastasis-free survival (DMFS), and local relapse-free survival (LRFS). Recursive partitioning analysis (RPA) modelling incorporating T-/N-categories and GTVp/GTVnd yielded four T-N-volume (TNV) risk groupings with disparate OS (p < 0.001). TNV risk stratification outperformed GTVp/GTVnd and eighth edition TNM for predicting OS (AUC 0.643 vs. 0.541–0.591; p < 0.001), DFS (0.629 vs. 0.545–0.580; p < 0.001), and DMFS (0.652 vs. 0.522–0.621; p < 0.001). NACT + concurrent chemoradiotherapy (CCRT) over NACT + IMRT was not superior for low- and low–intermediate-risk groupings (p > 0.05 for both), but superior for intermediate- and high-risk groupings in terms of OS (HR 0.68 (95% CI 0.47–0.99) for intermediate risk, 0.73 (0.55–0.97) for high risk; both p < 0.05). Overall, GTVp/GTVnd represent effective indicators for prognostication and decision-making in LA-NPC after NACT.

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.

Third Epidemiological Analysis of Nasopharyngeal Carcinoma in the Central Region of Japan from 2006 to 2015

The present study aimed to clarify the incidence and clinical outcomes of nasopharyngeal carcinoma (NPC) in the Chubu region of Japan from 2006 to 2015, compared with previous reports. A retrospective analysis was conducted based on medical records from 40 hospitals located in the Chubu region in the central Japanese main island, with a population of around 22.66 million individuals. This study was designed in line with to two previous clinical studies into NPC conducted in the same area of Japan. We recruited NPC patients diagnosed in hospitals across this area over a 10-year period (2006–2015) using a questionnaire about sex, age, primary site, clinical symptoms, pathology, Union for International Cancer Control (UICC) staging, serological exam, treatment, and survival. A total of 620 NPC patients were identified. The age-standardized incidence of NPC from 2006 to 2015 was 0.27 per 100,000 individuals per year. There were no significant differences between this study and the previous two studies conducted in the same area of Japan. The five-year overall survival rate for all patients was 75.9%, while those for patients with stages I, II, III, and IVA were 97%, 91%, 79%, and 68%, respectively. The age-standardized annual incidence of NPC in the present study was 0.27 per 100,000 individuals per year, which was relatively low and stable. The five-year overall survival rate for all NPC patients was significantly improved in this decade compared with previous studies. The smoking rates in male and female NPC patients were 64.5% and 18.8%, respectively, thereby suggesting the involvement of smoking in the incidence of NPC.

Radiomics Model to Predict Early Progression of Nonmetastatic Nasopharyngeal Carcinoma after Intensity Modulation Radiation Therapy: A Multicenter Study

Purpose

To examine the prognostic value of a machine learning model trained with pretreatment MRI radiomic features in the assessment of patients with nonmetastatic nasopharyngeal carcinoma (NPC) who are at risk for 3-year disease progression after intensity-modulated radiation therapy and to explain the radiomics features in the model.

Materials and Methods

A total of 277 patients with nonmetastatic NPC admitted between March 2008 and December 2014 at two imaging centers were retrospectively reviewed. Patients were allocated to a discovery or validation cohort based on where they underwent MRI (discovery cohort, n = 217; validation cohort, n = 60). A total of 525 radiomics features extracted from contrast material-enhanced T1- or T2-weighted MRI studies and five clinical features were subjected to radiomic machine learning modeling to predict 3-year disease progression. Feature selection was performed by analyzing robustness to resampling, reproducibility between observers, and redundancy. Features for the final model were selected with Kaplan-Meier analysis and the log-rank test. A support vector machine was used as the classifier for the model. To interpret the pattern learned from the model, Shapley additive explanations (SHAP) was applied.

Results

The final model yielded an area under the receiver operating characteristic curve of 0.80 in both the discovery (95% bootstrap confidence interval: 0.80, 0.81) and independent validation (95% bootstrap confidence interval: 0.73, 0.89) cohorts. Analysis with SHAP revealed that tumor shape sphericity, first-order mean absolute deviation, T stage, and overall stage were important factors in 3-year disease progression.

Conclusion

These results add to the growing evidence of the role of radiomics in the assessment of NPC. By using explanatory techniques, such as SHAP, the complex interaction of features learned by the model may be understood.© RSNA, 2019Supplemental material is available for this article.

Tumor volume/metabolic information can improve the prognostication of anatomy based staging system for nasopharyngeal cancer? Evaluation of the 8th edition of the AJCC/UICC staging system for nasopharyngeal cancer

Purpose

We evaluated prognostic value of the 8th edition of the American Joint Committee on Cancer/International Union for Cancer Control (AJCC/UICC) staging system for nasopharyngeal cancer and investigated whether tumor volume/metabolic information refined prognostication of anatomy based staging system.

Materials and Methods

One hundred thirty-three patients with nasopharyngeal cancer who were staged with magnetic resonance imaging (MRI) and treated with intensity-modulated radiotherapy (IMRT) between 2004 and 2013 were reviewed. Multivariate analyses were performed to evaluate prognostic value of the 8th edition of the AJCC/UICC staging system and other factors including gross tumor volume and maximum standardized uptake value of primary tumor (GTV-T and SUV-T).

Results

Median follow-up period was 63 months. In multivariate analysis for overall survival (OS), stage group (stage I-II vs. III-IVA) was the only significant prognostic factor. However, 5-year OS rates were not significantly different between stage I and II (100% vs. 96.2%), and between stage III and IVA (80.1% vs. 71.7%). Although SUV-T and GTV-T were not significant prognostic factors in multivariate analysis, those improved prognostication of stage group. The 5-year OS rates were significantly different between stage I-II, III-IV (SUV-T ≤ 16), and III-IV (SUV-T > 16) (97.2% vs. 78% vs. 53.8%), and between stage I, II-IV (GTV-T ≤ 33 mL), and II-IV (GTV-T > 33 mL) (100% vs. 87.3% vs. 66.7%).

Conclusion

Current anatomy based staging system has limitations on prognostication for nasopharyngeal cancer despite the most accurate assessment of tumor extent by MRI. Tumor volume/metabolic information seem to improve prognostication of current anatomy based staging system, and further studies are needed to confirm its clinical significance.

Prognostic value of tumor burden in nasopharyngeal carcinoma

BACKGROUND

The prognostic value of primary tumor volume (TV) in nasopharyngeal carcinoma (NPC) has been confirmed. However, studies of the prognosis value of tumor burden, including TV and nodal volume (NV), have been relatively infrequent. Therefore, the aim of this study was to evaluate the prognostic value of tumor burden in NPC patients treated with intensity-modulated radiotherapy.

METHODS

Receiver operating characteristics curves were generated to determine rational cutoff points for TV and NV. The volumes identified included 12.5, 25.0, and 50.0 mL, and 0, 12.5, and 25 mL, respectively. According to these cutoff volumes, four subgroups were established for TV as TV1-TV4, and four subgroups were established for NV as NV0-NV3. Then, the entire cohort (992 NPC patients) was divided into 16 subgroups according to these four levels of TV and NV. Based on similarities in the 5-year overall survival (OS) rates for these 16 subgroups, four patient groups were established, G1-G4.

RESULTS

The mean TV and NV values for our cohort were 39.5±30.8 mL and 16.5±17.6 mL, respectively. The 5-year distant failure-free rate, the 5-year disease-free survival rate, and the 5-year OS rate for G3 and G4 were significantly lower than those for G1 and G2. In particular, the OS curves of the four patient groups were significantly separated. A multivariate analysis identified TV >50 mL, T-stage (3-4), and N-stage (2-3) as adverse prognostic factors for OS.

CONCLUSIONS

The results of this study demonstrate that tumor burden has a significant prognostic value for NPC patients treated with intensity-modulated radiotherapy. Hence, tumor burden, including TV and NV, should be incorporated into the current staging system for NPC to improve prognostic significance.

Prognostic values of the integrated model incorporating the volume of metastatic regional cervical lymph node and pretreatment serum Epstein-Barr virus DNA copy number in predicting distant metastasis in patients with N1 nasopharyngeal carcinoma

Background

According to the 7th edition of the American Joint Committee on Cancer (AJCC) staging system, over 50% of patients with nasopharyngeal carcinoma (NPC) have N1 disease at initial diagnosis. However, patients with N1 NPC are relatively under-researched, and the metastasis risk of this group is not well-stratified. This study aimed to evaluate the prognostic values of gross tumor volume of metastatic regional lymph node (GTVnd) and pretreatment serum copy number of Epstein–Barr virus (EBV) DNA in predicting distant metastasis of patients with N1 NPC, and to develop an integrated prognostic model that incorporates GTVnd and EBV DNA copy number for this group of patients.

Methods

The medical records of 787 newly diagnosed patients with nonmetastatic, histologically proven N1 NPC who were treated at Sun Yat-sen University Cancer Center between November 2009 and February 2012 were analyzed. Computed tomography-derived GTVnd was measured using the summation-of-area technique. Blood samples were collected before treatment to quantify plasma EBV DNA. The receiver operating characteristic (ROC) curve analysis was used to evaluate the cut-off point for GTVnd, and the area under the ROC curve was used to assess the predicted validity of GTVnd. The survival rates were assessed by Kaplan–Meier analysis, and the survival curves were compared using a log-rank test. Multivariate analysis was conducted using the Cox proportional hazard regression model.

Results

The 5-year distant metastasis-free survival (DMFS) rates for patients with GTVnd > 18.9 vs. ≤ 18.9 mL were 82.2% vs. 93.2% (P < 0.001), and for patients with EBV DNA copy number > 4000 vs. ≤ 4000 copies/mL were 83.5% vs. 93.9% (P < 0.001). After adjusting for GTVnd, EBV DNA copy number, and T category in the Cox regression model, both GTVnd > 18.9 mL and EBV DNA copy number > 4000 copies/mL were significantly associated with poor prognosis (both P < 0.05). According to combination of GTVnd and EBV DNA copy number, all patients were divided into low-, moderate-, and high-risk groups, with the 5-year DMFS rates of 96.1, 87.4, and 73.8%, respectively (P < 0.001). Multivariate analysis confirmed the prognostic value of this model for distant metastatic risk stratification (hazard ratio [HR], 4.17; 95% confidence interval [CI] 2.34–7.59; P < 0.001).

Conclusions

GTVnd and serum EBV DNA copy number are independent prognostic factors for predicting distant metastasis in NPC patients with N1 disease. The prognostic model incorporating GTVnd and EBV DNA copy number may improve metastatic risk stratification for this group of patients.

Standardized tumor volume: an independent prognostic factor in advanced nasopharyngeal carcinoma

The study evaluated the prognostic effect of standardized tumor volume in patients with advanced nasopharyngeal carcinoma (NPC) treated with concurrent chemoradiotherapy. Between Jan 1, 2009 and December 30, 2012, 143 patients diagnosed with NPC in UICC stage III–IVb by histopathology were enrolled in the study. These patients underwent intensity-modulated radiotherapy combined with concurrent chemotherapy. The three-dimensional images of tumor volume were reconstructed automatically by the treatment planning system. SGTVnx was calculated based on GTVnx/person’s volume. SGTVnd was calculated based on GTVnd/person’s volume. SGTVnx was significantly associated with the 5-year overall survival (OS), disease-free survival (DFS), DMFS, and LRFS rates in univariate and multivariate analyses. Although SGTVnd was associated with the 5-year OS, DFS, and DMFS rates, it was not an independent prognostic factor for LRFS. In receiver operating characteristic (ROC) curve analysis, 1.091 and 0.273 were determined as the cut-off points for SGTVnx and SGTVnd, respectively. The 5-year OS, DFS, DMFS, and LRFS rates for patients with a SGTVnx > 1.091 vs. SGTVnx ≤ 1.091 was 65.4% vs. 93.4% (P < 0.001), 65.2% vs. 94.8% (P < 0.001), 71.4% vs. 97.4% (P < 0.001), and 84.8% vs. 97.3% (P = 0.003), respectively, for SGTVnd > 0.273 vs. SGTVnd ≤ 0.273 was 70.3% vs. 96.5% (P < 0.001), 70.1% vs. 94.8% (P < 0.001), 77.5% vs. 98.2% (P < 0.001), and 88.5% vs. 96.6% (P = 0.049), respectively. UICC stage grouping, T classification, N classification, and sex were not found to be independent prognostic factors for NPC. Standardized tumor volume was an independent prognostic factor for NPC that might improve the current NPC TNM classification system and provide new clinical evidence for personalized treatment strategies.

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

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

Prediction of distant metastases from nasopharyngeal carcinoma: Improved diagnostic performance of MRI using nodal volume in N1 and N2 stage disease

PURPOSE

To determine if the magnetic resonance imaging (MRI) of the head and neck can predict distant metastases (DM) from nasopharyngeal carcinoma (NPC).

METHODS AND MATERIALS

MRI examinations of 763 NPC patients were assessed for primary tumour stage (T), nodal stage (N), primary tumour volume (PTV) and total nodal volume (NV). The association between MRI and clinical parameters were examined in DM+ and DM- patients using logistic regression and for distant metastases free survival (DMFS) using cox regression. Optimum thresholds were assessed by receiver-operating characteristics analysis, and positive predictive value (PPV) and odds ratio (OR) calculated.

RESULTS

Distant metastases were present in 181/763 NPC patients (23.7%). Higher N stage and NV were the independent predictors of DM (p<0.001 and 0.018 respectively) and poor DMFS (p=0.001 and 0.030 respectively). Addition of NV (threshold≥32.8cm³) to the N stage improved the PPVs and ORs for DM in stage N1 (from 18.9% to 31.8% and 5.613 to 11.133 respectively) and stage N2 (from 40.4% to 60.8% and 16.189 to 36.979 respectively) but not in stage N3 (68.3% to 68.6% and 51.385 to 52.052 respectively).

CONCLUSION

MRI N stage and NV were independent predictors of DM and DMFS. The addition of NV in NPC patients with bulky N1 and N2 disease improved the ability of MRI to predict DM.

Prognostic value and predictive threshold of tumor volume for patients with locally advanced nasopharyngeal carcinoma receiving intensity-modulated radiotherapy

Background

Gross target volume of primary tumor (GTV-P) is very important for the prognosis prediction of patients with nasopharyngeal carcinoma (NPC), but it is unknown whether the same is true for locally advanced NPC patients treated with intensity-modulated radiotherapy (IMRT). This study aimed to clarify the prognostic value of tumor volume for patient with locally advanced NPC receiving IMRT and to find a suitable cut-off value of GTV-P for prognosis prediction.

Methods

Clinical data of 358 patients with locally advanced NPC who received IMRT were reviewed. Receiver operating characteristic (ROC) curves were used to identify the cut-off values of GTV-P for the prediction of different endpoints [overall survival (OS), local relapse-free survival (LRFS), distant metastasis-free survival (DMFS), and disease-free survival (DFS)] and to test the prognostic value of GTV-P when compared with that of the American Joint Committee on Cancer T staging system.

Results

The 358 patients with locally advanced NPC were divided into two groups by the cut-off value of GTV-P as determined using ROC curves: 219 (61.2%) patients with GTV-P ≤46.4 mL and 139 (38.8%) with GTV-P >46.4 mL. The 3-year OS, LRFS, DMFS, and DFS rates were all higher in patients with GTV-P ≤46.4 mL than in those with GTV-P > 46.4 mL (all P < 0.05). Multivariate analysis indicated that GTV-P >46.4 mL was an independent unfavorable prognostic factor for patient survival. The ROC curve verified that the predictive ability of GTV-P was superior to that of T category (P < 0.001). The cut-off values of GTV-P for the prediction of OS, LRFS, DMFS, and DFS were 46.4, 57.9, 75.4 and 46.4 mL, respectively.

Conclusion

In patients with locally advanced NPC, GTV-P >46.4 mL is an independent unfavorable prognostic indicator for survival after IMRT, with a prognostic value superior to that of T category.

Tumor Volume Predicts Survival Rate of Advanced Nasopharyngeal Carcinoma Treated with Concurrent Chemoradiotherapy

Objective

To delineate the prognostic value of primary gross tumor volume (GTVp) for patients with locoregionally advanced nasopharyngeal carcinoma (NPC) treated with concurrent chemoradiotherapy.

Study Design

Analysis of prognostic variables in a prospective cohort.

Setting

Department of Radiotherapy, First Affiliated Hospital of Guangxi Medical University, China.

Subjects and Methods

Between January 2006 and August 2008, 249 patients with stage III-IVb NPC, all treated by intensity-modulated radiotherapy plus concurrent chemotherapy, were included in this multicenter prospective study. GTVp was measured with treatment-planning computed tomography or magnetic resonance imaging scans.

Results

GTVp was significantly associated with locoregional control, distant metastasis, and overall survival for patients with advanced NPC. Furthermore, T classification was not an independent prognostic factor. In receiver operator receiver operating characteristic curve analysis, 33 mL was determined as the cutoff points of GTVp for OS and locoregional control. Patients with a GTVp ≥33 mL had poorer OS, worse locoregional control, and more distant metastasis than patients with a GTVp <33 mL ( P = .006, .009, .002, and .007, respectively).

Conclusions

GTVp had significant prognostic value for patients with advanced NPC. The incorporation of GTVp could improve the current TNM classification system.

Prognostic efficacy of combining tumor volume with Epstein-Barr virus DNA in patients treated with intensity-modulated radiotherapy for nasopharyngeal carcinoma

OBJECTIVES

To evaluate the prognostic effect of combining tumor volume with pre-treatment plasma Epstein-Barr virus DNA (EBV DNA) in patients treated with intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC).

MATERIALS AND METHODS

A total of 180 consecutive NPC patients enrolled in this observational, prospective study and underwent IMRT. Tumor volume was delineated with IMRT planning system and plasma EBV DNA level was quantified by polymerized chain-reaction assay. The effects of tumor volume and EBV DNA level, either alone or in combination, on 5-year overall survival (OS) were cross-compared.

RESULTS

The 5-year OS in patients with gross tumor volume of nasopharynx (GTVnx)⩽20cc and >20cc was significantly different (P=0.001). The 5-year OS in patients with EBV DNA <6800copies/mL and ⩾6800copies/mL was also significantly different (P<0.001). Based on the combination of GTVnx with EBV DNA, the 5-year OS in different subgroups was: low-risk (100%), intermediate-risk (87.8%, 95% CI: 70.6-95.2%) and high-risk (61.3%, 95% CI: 47.9-72.2%). Patients with small tumor volume and high EBV DNA level had a worse prognosis than those with large tumor and low EBV DNA level. Patients with low EBV DNA levels, and either small or large tumor volumes, had favorable prognosis. According to small or large tumor volume, patients with high EBV DNA level were divided into intermediaterisk and high-risk subgroups.

CONCLUSION

Combining tumor volume with pre-treatment plasma EBV DNA level altered survival-risk definition for subgroups of NPC patients and this combination, more than individual factors alone, improved the accuracy of prognostic evaluation.

Diffusion-Weighted Imaging of Nasopharyngeal Carcinoma: Can Pretreatment DWI Predict Local Failure Based on Long-Term Outcome?

BACKGROUND AND PURPOSE

Pretreatment prediction of patients with nasopharyngeal carcinoma who will fail conventional treatment would potentially allow these patients to undergo more intensive treatment or closer posttreatment monitoring. The aim of the study was to determine the ability of pretreatment DWI to predict local failure in patients with nasopharyngeal carcinoma based on long-term clinical outcome.

MATERIALS AND METHODS

One hundred fifty-eight patients with pretreatment DWI underwent analysis of the primary tumor to obtain the ADC mean, ADC skewness, ADC kurtosis, volume, and T-stage. Univariate and multivariate analyses using logistic regression were performed to compare the ADC parameters, volume, T-stage, and patient age in primary tumors with local failure and those with local control, by using a minimum of 5-year follow-up to confirm local control.

RESULTS

Local control was achieved in 131/158 (83%) patients (range, 60.3-117.7 months) and local failure occurred in 27/158 (17%) patients (range, 5.2-79.8 months). Compared with tumors with local control, those with local failure showed a significantly lower ADC skewness (ADC values with the greatest frequencies were shifted away from the lower ADC range) (P = .006) and lower ADC kurtosis (curve peak broader) (P = .024). The ADC skewness remained significant on multivariate analysis (P = .044). There was a trend toward higher tumor volumes in local failure, but the volume, together with T-stage and ADC mean, were not significantly different between the 2 groups.

CONCLUSIONS

Pretreatment DWI of primary tumors found that the skewness of the ADC distribution curve was a predictor of local failure in patients with nasopharyngeal carcinoma, based on long-term clinical outcome.

A comparison between the Chinese 2008 and the 7th edition AJCC staging systems for nasopharyngeal carcinoma

OBJECTIVES

The Chinese 1992 staging system for nasopharyngeal carcinoma (NPC) was revised in 2008 and was renamed as the Chinese 2008 staging system. The seventh edition of the American Joint Committee on Cancer (AJCC) staging manual also defined new rules for classifying NPC in 2010. The purpose of the current study is to compare the 2 in terms of patient distribution and efficacy in predicting prognosis.

METHODS

A total of 816 patients with untreated nondisseminated NPC who underwent magnetic resonance imaging scan of the nasopharynx and neck were studied retrospectively. All magnetic resonance imaging scans were reevaluated independently by 2 radiologists specialized in head and neck cancers. All patients were restaged according to the Chinese 2008 staging system and the AJCC staging system of NPC.

RESULTS

Using the 2 staging systems, the consistency for patient distributions in T, N, and overall stages was found to be moderate, with the κ value of 0.65, 0.54, and 0.46, respectively. According to the Chinese 2008 and the AJCC staging systems, the proportion of patients in stages I, II, III, and IV accounted for 2.3% versus 2.3%, 11.0% versus 23.7%, 39.4% versus 49.1%, and 47.3% versus 24.9%, respectively. The AJCC T classification was better in predicting the 5-year local relapse-free survival, whereas the Chinese 2008 N classification was superior in predicting the 5-year distant metastasis-free survival. However, survival curves for the 5-year overall survival were comparable in both systems.

CONCLUSIONS

We revealed a slightly better patient distribution of overall stage with AJCC comparing with the Chinese 2008 staging system. The prognostic value of AJCC T classification was considered to be better, whereas that of Chinese 2008 N classification was superior.

Nasopharyngeal carcinoma with paranasal sinus invasion: the prognostic significance and the evidence-based study basis of its T-staging category according to the AJCC staging system

BACKGROUND

To evaluate the prognostic significance of paranasal sinus invasion for patients with NPC and to provide empirical proofs for the T-staging category of paranasal sinus invasion according to the AJCC staging system for nasopharyngeal carcinoma.

METHODS

The clinical records and imaging studies of 770 consecutive patients with newly diagnosed, untreated, and nondisseminated NPC were reviewed retrospectively. The overall survival, distant metastasis-free survival, and local relapse-free survival of these patients were analyzed using the Kaplan-Meier method, and the differences were compared using the log-rank test.

RESULTS

The incidence of paranasal sinus invasion was 23.6%, with the rate of incidence of sphenoid sinus invasion being the highest. By multivariate analysis, paranasal sinus invasion was shown to be an independent prognostic factor for overall survival, distant metastasis-free survival, and local relapse-free survival (p < 0.05 for all). No significant differences in overall survival, distant metastasis-free survival, and local relapse-free survival were observed between patients with sphenoid sinus invasion alone and those with maxillary sinus and ethmoid sinus invasion (p = 0.87, p = 0.80, and p = 0.37, respectively). The overall survival, distant metastasis-free survival, and local relapse-free survival for patients with stage T3 disease with paranasal sinus invasion were similar to the survival rates for patients with stage T3 disease without paranasal sinus invasion (p = 0.22, p = 0.15, and p = 0.93, respectively). However, the rates of overall survival and local relapse-free survival were better for patients with stage T3 disease with paranasal sinus invasion than for patients with stage T4 disease (p < 0.01, and p = 0.03, respectively).

CONCLUSIONS

Paranasal sinus invasion is an independent negative prognostic factor for NPC, regardless of which sinus is involved. Our results confirm that it is scientific and reasonable for the AJCC staging system for nasopharyngeal carcinoma to define paranasal sinus invasion as stage T3 disease.

Is replacement of the supraclavicular fossa with the lower level classification based on magnetic resonance imaging beneficial in nasopharyngeal carcinoma?

PURPOSE AND OBJECTIVES

To investigate the pattern of lymph node metastasis and treatment outcome after intensity-modulated radiotherapy (IMRT) in nasopharyngeal carcinoma (NPC), and assess the possibility of replacing Ho's supraclavicular fossa (SCF) with the lower level (LL; cervical extension below caudal edge of cricoid cartilage) based on magnetic resonance imaging (MRI) as a criterion for N3 disease.

METHODS AND MATERIALS

We retrospectively reviewed 749 patients with biopsy-proven non-metastatic NPC treated with IMRT. Lymph node metastasis was mapped using the 2013 International Consensus Guidelines.

RESULTS

Cervical lymph node (CLN) laterality, CLN greatest dimension (>60 vs. ⩽60 mm) and Ho's SCF were independent prognostic factors for disease-free survival (DFS) and distant metastasis-free survival (DMFS; P<0.01) in multivariate analysis. Replacing Ho's SCF with the LL was also predictive for DFS and DMFS (P<0.01). Compared to the 7th UICC/AJCC, N-categories based on the LL provided more satisfactory distinction between hazard ratios for distant and disease failure for each N-category. N3a and N3b as defined by the 7th UICC/AJCC had similar DMFS (P=0.31) and DFS (P=0.21).

CONCLUSIONS

Replacing Ho's SCF with the LL is simple and practical. The N-category staging system could be further simplified by merging N3 subcategories.

A new T classification based on masticator space involvement in nasopharyngeal carcinoma: a study of 742 cases with magnetic resonance imaging

Background

The aim of this study was to investigate the prognostic significance and various classifications for anatomic masticator space involvement (MSI) in patients with nasopharyngeal carcinoma (NPC).

Methods

This study retrospectively analyzed 742 patients with untreated nondisseminated NPC who underwent magnetic resonance imaging (MRI) scan of the nasopharynx and neck. The MSI was graded according to different anatomic features. The overall survival (OS), local relapse-free survival (LRFS), distant metastasis-free survival (DMFS), and disease-free survival (DFS) of the patients with different MSI grades were analyzed using the Kaplan-Meier method and log-rank tests.

Results

The frequency of MSI was 24.1% (179/742). The 5-year OS, LRFS, DMFS, DFS for NPC patients with versus without MSI were 70.9% versus 82.5% (P = 0.001), 94.1% versus 91.4% (P = 0.511), 81.4% versus 88.7% (P = 0.021), and 78.0% versus 83.5% (P = 0.215), respectively. Significant differences in OS were also found among different MSI groups. In the patients with MSI, the OS of the group with medial and/or lateral pterygoid involvement (MLPI) NPC was 73.9% compared to 51.3% (P < 0.0001) in the patients with infratemporal fossa involvement (IFI).

Conclusions

MSI was an independent prognostic factor for OS and DMFS. NPCs invading the masticator space should be separately categorized into MLPI and IFI prognostic groups. We suggest that MLPI should be staged as T3 while IFI is staged as T4 disease in future TNM staging revision.

Local failure patterns for patients with nasopharyngeal carcinoma after intensity-modulated radiotherapy

Background

To investigate the clinical feature and the local failure patterns after intensity-modulated radiotherapy for nasopharyngeal carcinoma.

Methods

Between March 2007 and July 2009, 710 patients with nasopharyngeal carcinoma were treated with intensity-modulated radiotherapy. The magnetic resonance imagings obtained at recurrence were registered with the original planning computed tomography for dosimetry analysis.

Results

With a median follow-up of 38 months, 34 patients have developed local recurrence (32 cases valid). The incidence of invasion to nasopharynx, parapharyngeal space and the retropharyngeal space by the primary tumors was 100%, 75.0% and 62.5%, respectively, but 78.1%, 34.4% and 21.9% at recurrence, respectively. The rate of invasion to ethmoid sinus was 3.1% by the primary tumors but 28.1% at recurrence (p = 0.005). The topographic analysis of the local failure patterns showed "central" in 16 patients; "marginal" in 9; and "outside" in 7. The median volumes of primary gross tumor were 45.84 cm³ in the central failure group, 29.44 cm³ in the marginal failure group, and 21.52 cm³ in the outside failure group, respectively (p = 0.012), and the median volumes of primary clinical target1 were 87.28 cm³, 61.90 cm³ and 58.74 cm³ in the three groups, respectively (p = 0.033).

Conclusions

In patients with nasopharyngeal carcinoma treated with intensity-modulated radiotherapy, the recurrent tumors had their unique characteristic and regularity of invasion to adjacent structures. "Central" failure was the major local failure pattern. The volumes of primary gross tumor and clinical target1 were significantly correlated with recurrent patterns. Employ more aggressive approaches to tumor cells which will be insensitive to radiotherapy may be an effective way to reduce the central failure.

Prognostic value of tumor volume for patients with nasopharyngeal carcinoma treated with concurrent chemotherapy and intensity-modulated radiotherapy

PURPOSE

We aimed to analyze prognostic factors in patients with nasopharyngeal carcinoma (NPC) treated with concurrent chemotherapy and intensity-modulated radiotherapy (IMRT); in addition, we aimed to elucidate the value of primary gross tumor volume (GTVp) in predicting prognosis of patients.

METHODS

Between February 2001 and December 2008, 321 patients with NPC treated with concurrent chemotherapy and IMRT were analyzed retrospectively. GTVp was calculated from treatment planning computed tomography scans. A receiver operating characteristics (ROC) curve was used to determine the best cutoff point of GTVp.

RESULTS

The 5-year local failure-free survival (LFFS), distant metastasis-free survival (DMFS), disease-free survival (DFS), and overall survival (OS) for NPC patients were 93.8, 80.1, 73.0, and 83.7 %, respectively. Univariate and multivariate analyses indicated that GTVp had exhibited a statistically significant correlation with LFFS, DMFS, DFS, and OS (P < 0.05, all), whereas T classification was not an independent prognostic factor. According to ROC curve analysis, 49 and 19 mL were determined as the cutoff points of GTVp for local control and distant metastasis, respectively. Based on this, 321 patients were divided into three volume subgroups. LFFS, DMFS, DFS, and OS demonstrated significant differences among patients in different volume subgroups (P < 0.001, all) and were superior to T classification for predicting prognosis of NPC patients.

CONCLUSIONS

Primary gross tumor volume is an independent prognostic factor in local control, distant metastasis, disease-free survival, and overall survival in NPC. An adjusted TNM staging system that includes GTVp as a quantitative indicator to evaluate prognosis is warranted.

Staging of nasopharyngeal carcinoma--the past, the present and the future

This article reviews the evolution of the International Union Against Cancer/American Joint Committee on Cancer staging system for nasopharyngeal carcinoma. With the increasing availability of newer imaging methods, more sophisticated radiotherapy techniques and rapidly evolving molecular assays, we also examine newer clinical features that might have impact on staging. A new version of the staging system taking into account of some of these factors is also proposed.

Plasma uric acid and tumor volume are highly predictive of outcome in nasopharyngeal carcinoma patients receiving intensity modulated radiotherapy

Background

The combined predictive value of plasma uric acid and primary tumor volume in nasopharyngeal carcinoma (NPC) patients receiving intensity modulated radiation therapy (IMRT) has not yet been determined.

Methods

In this retrospective study, plasma uric acid level was measured after treatment in 130 histologically-proven NPC patients treated with IMRT. Tumor volume was calculated from treatment planning CT scans. Overall (OS), progression-free (PFS) and distant metastasis-free (DMFS) survival were compared using Kaplan-Meier analysis and the log rank test, and Cox multivariate and univariate regression models were created.

Results

Patients with a small tumor volume (<27 mL) had a significantly better DMFS, PFS and OS than patients with a large tumor volume. Patients with a high post-treatment plasma uric acid level (>301 μmol/L) had a better DMFS, PFS and OS than patients with a low post-treatment plasma uric acid level. Patients with a small tumor volume and high post-treatment plasma uric acid level had a favorable prognosis compared to patients with a large tumor volume and low post-treatment plasma uric acid level (7-year overall OS, 100% vs. 48.7%, P <0.001 and PFS, 100% vs. 69.5%, P <0.001).

Conclusions

Post-treatment plasma uric acid level and pre-treatment tumor volume have predictive value for outcome in NPC patients receiving IMRT. NPC patients with a large tumor volume and low post-treatment plasma uric acid level may benefit from additional aggressive treatment after IMRT.

Prognostic significance of tumor volume in patients with nasopharyngeal carcinoma undergoing intensity-modulated radiation therapy

BACKGROUND

This study was undertaken to analyze the correlation between primary gross tumor volume (GTVp) and prognosis in patients with nasopharyngeal carcinoma (NPC) undergoing intensity-modulated radiation therapy (IMRT).

METHODS

Between February 2001 and December 2006, 305 patients with NPC treated with IMRT were analyzed retrospectively. GTVp was calculated from treatment planning CT scans.

RESULTS

Univariate and multivariate analyses indicated that GTVp had a statistically significant correlation to local control, distant metastasis, and overall survival in patients with NPC, whereas T classification was not an independent prognostic factor. Among patients classified with N0-1 and N2-3, there were significant differences in the rates of distant metastasis between those with GTVp smaller and larger than 25 mL (p < .001 and p = .002, respectively).

CONCLUSIONS

GTVp is highly significant in evaluating local control, distant metastasis, and overall survival of patients with NPC treated with IMRT. Therefore, it is recommended that GTVp be included in the new TNM classification system.

Significance of primary tumor volume and T-stage on prognosis in nasopharyngeal carcinoma treated with intensity-modulated radiation therapy

OBJECTIVE

The aim of this study was to evaluate the effect of the primary tumor volume on prognosis in nasopharyngeal carcinoma treated with intensity-modulated radiation therapy.

METHODS

Between August 2003 and April 2005, 112 patients with Stage I-IVB nasopharyngeal carcinoma treated by intensity-modulated radiation therapy were included. Measurement of the primary tumor volume was based on contrast-enhanced computed tomography scans before treatment. A receiver operating characteristics curve was used to determine the best cut-off point of the primary tumor volume.

RESULTS

The mean primary tumor volume for 112 patients with nasopharyngeal carcinoma was 33.9 ± 28.7 ml. Within the framework of UICC T-staging, all patients were divided into four groups according to the primary tumor volume. We call it the volume stage (V1 <15.65 ml, V2 = 15.65-24.25 ml, V3 = 24.25-50.55 ml and V4 >50.55 ml). The 5-year overall survival rates for V1, V2, V3 and V4 were 88.5, 83.3, 82.4 and 54.5% (P = 0.014), respectively. The cumulative survival curves for V1, V2 and V3 were very close, but clearly separated from V4. In addition, Cox proportional hazards regression model analysis showed that a primary tumor volume >50 ml was an independent risk factor for radiotherapy (risk ratio = 3.485, P = 0.025).

CONCLUSIONS

This study demonstrated that the primary tumor volume had significantly impacted on the prognosis of patients with nasopharyngeal carcinoma. We proposed that the primary tumor volume should be considered as an additional stage indicator in the new revision of the clinical stage of nasopharyngeal carcinoma.

Validation of bidimensional measurement in nasopharyngeal carcinoma

BACKGROUND

Our previous study showed a close relationship between computed tomography (CT)-derived bidimensional measurement of primary tumor and retropharyngeal nodes (BDMprn) and gross tumor volume of primary tumor and retropharyngeal nodes (GTVprn) in nasopharyngeal carcinoma (NPC) and better prognosis for NPC patients with smaller BDMprn. In this study, we report the results on of a study to validate the use of BDM in a separate cohort of NPC patients.

METHODS

We retrospectively reviewed 103 newly diagnosed NPC cases who were treated with radiotherapy/concurrent chemoradiotherapy (CCRT) or CCRT with adjuvant chemotherapy from 2002 to 2009. We used magnetic resonance imaging (MRI) to measure BDMprn. We calculated overall survival, recurrence-free and distant metastasis-free survival curves and set a BDMprn cut off point to categorize patients into a high- or low-risk group. We then used Cox proportional hazard model to evaluate the prognostic influence of BDMprn after correcting age, gender and chemotherapy status.

RESULTS

After adjusting for age, gender, and chemotherapy status, BDMprn remained an independent prognostic factor for distant metastasis [Hazard ratio (HR) = 1.046; P = 0.042] and overall survival (HR = 1.012; P = 0.012). Patients with BDMprn < 15 cm2 had a greater 3-year overall survival rate than those with BDMprn > or = 15 cm2 (92.3% vs. 73.7%; P = 0.009). They also had a greater 3-year distant metastasis-free survival (94% vs.75%; P = 0.034).

CONCLUSION

The predictive ability of BDMprn was validated in a separate NPC cohort. A BDMprn of 15 cm2 can be used to separate NPC patients into high- and low-risk groups and predict survival rates and metastasis potential. It can, therefore, be used as a reference to design clinical trials, predict prognosis, and make treatment decisions.

[Update on medical therapies of nasopharyngeal carcinomas]

Nasopharyngeal carcinomas (NPC) are predominantly of undifferentiated type (UCNT or undifferentiated carcinoma of nasopharyngeal type), rare (<1/100,000) and sporadic in occidental countries, but endemic in the Mediterranean area of intermediate incidence (2 to 10/100,000) and highly frequent (>10/100,000) in South East Asia. NPC staging is based on TNM UICC 2002 that has a prognostic and therapeutic orientation impact. Irradiation of the primitive tumor and its extensions remains the standard loco-regional treatment. The recent introduction of primary and concomitant chemotherapy leads to an improvement in terms of overall and disease-free survival, specially for for high-risk-patients (T3-4 and N2-3 disease). Prognosis remain linked to T, N, histologic type and quality of response to chemotherapy and radiotherapy.