Proposed lymph node staging system using the International Consensus Guidelines for lymph node levels is predictive for nasopharyngeal carcinoma patients from endemic areas treated with intensity modulated radiation therapy

Matted Lymph Nodes on MRI in Nasopharyngeal Carcinoma: Prognostic Factor and Potential Indication for Induction Chemotherapy Benefits

BACKGROUND

Lymph node characteristics markedly affect nasopharyngeal carcinoma (NPC) prognosis. Matted node (MN), an important characteristic for lymph node, lacks explored MRI-based prognostic implications.

PURPOSE

Investigate MRI-determined MNs' prognostic value in NPC, including 5-year overall survival (OS), distant metastasis-free survival (DMFS), local recurrence-free survival (LRFS), progression-free survival (PFS), and its role in induction chemotherapy (IC).

STUDY TYPE

Retrospective cohort survival study.

POPULATION

Seven hundred ninety-two patients with non-metastatic NPC (female: 27.3%, >45-year old: 50.1%) confirmed by biopsy.

FIELD STRENGTH/SEQUENCE

5-T/3.0-T, T1-, T2- and post-contrast T1-weighted fast spin echo sequences acquired.

ASSESSMENT

MNs were defined as ≥3 nodes abutting with intervening fat plane replaced by extracapsular nodal spread (ENS). Patients were observed every 3 months for 2 years and every 6 months for 5 years using MRI. Follow-up extended from treatment initiation to death or final follow-up. MNs were evaluated by three radiologists with inter-reader reliability calculated. A 1:1 matched-pair method compared survival differences between MN-positive patients with or without IC. Primary endpoints (OS, DMFS, LRFS, PFS) were calculated from therapy initiation to respective event.

STATISTICAL TESTS

Kappa values assessed inter-reader reliability. Correlation between MN, ENS, and LNN was studied through Spearman's correlation coefficient. Clinical characteristics were calculated via Fisher's exact, Chi-squared, and Student's t-test. Kaplan-Meier curves and log-rank tests analyzed all time-to-event data. Confounding factors were included in Multivariable Cox proportional hazard models to identify independent prognostic factors. P-values <0.05 were considered statistically significant.

RESULTS

MNs incidence was 24.6%. MNs independently associated with decreased 5-year OS, DMFS, and PFS; not LRFS (P = 0.252). MN-positive patients gained significant survival benefit from IC in 5-year OS (88.4% vs. 66.0%) and PFS (76.4% vs. 53.5%), but not DMFS (83.1% vs. 69.9%, P = 0.145) or LRFS (89.9% vs. 77.8%, P = 0.140).

DATA CONCLUSION

MNs may independently stratify NPC risk and offer survival benefit from IC.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 2.

Study on carotid artery stenosis after radiotherapy for nasopharyngeal carcinoma

OBJECTIVE

This study investigated carotid artery stenosis (CAS) and associated risk factors in patients with nasopharyngeal carcinoma (NPC) post-radiotherapy.

MATERIALS AND METHODS

The observation group comprised 86 reexamined patients with NPC, divided into Group 1 and Group 2 based on post-radiotherapy duration, alongside 34 newly diagnosed patients with NPC (Group 0). Carotid artery ultrasonography and chi-square analysis were performed.

RESULTS

Moderate-to-severe vascular abnormalities were exclusively in Group 2. Considering mild vascular abnormalities as the standard, the overall vascular abnormality rates in Group 2 and Group 0 were 65.9% and 41.2%, respectively. In Group 2 and Group 0, the abnormality rates for unilateral carotid artery (UCA), common carotid artery (CCA), internal carotid artery (ICA), and external carotid artery (ECA) were 47.4% and 30.9%, 44.3% and 22.1%, 44.3% and 16.2%, and 39.8% and 5.9%, respectively. Comparing group 1 to group 0, only UCA abnormalities were statistically significant (45.4% vs. 30.9%). Considering moderate-to-severe vascular abnormalities as the standard, Group 2 had higher overall vascular, UCA, CCA, ICA, and ECA abnormality rates compared to Group 0. The age at revisit over 45 years, T stage, and N stage may influence CAS.

CONCLUSION

Radiation increasing CAS incidence after 3 years. So, regular examinations are recommended to dynamically monitor CAS after 3 years of radiotherapy.

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.

Radiologic extranodal extension for nodal staging in nasopharyngeal carcinoma

PURPOSE

Extranodal extension (ENE) has the potential to add value to the current nodal staging system (N8th) for predicting outcome in nasopharyngeal carcinoma (NPC). This study aimed to incorporate ENE, as well as cervical nodal necrosis (CNN) to the current stage N3 and evaluated their impact on outcome prediction. The findings were validated on an external cohort.

METHODS & MATERIALS

Pre-treatment MRI of 750 patients from the internal cohort were retrospectively reviewed. Predictive values of six modified nodal staging systems that incorporated four patterns of ENE and two patterns of CNN to the current stage N3 for disease-free survival (DFS) were compared with that of N8th using multivariate cox-regression and concordance statistics in the internal cohort. Performance of stage N3 for predicting disease recurrence was calculated. An external cohort of 179 patients was used to validate the findings.

RESULTS

Incorporation of advanced ENE, which infiltrates into adjacent muscle/skin/salivary glands outperformed the other five modifications for predicting outcomes (p < 0.01) and achieved a significantly higher c-index for 5-year DFS (0.69 vs 0.72) (p < 0.01) when compared with that of N8th staging system. By adding advanced ENE to the current N3 increased the sensitivity for predicting disease recurrence from 22.4 % to 47.1 %. The finding was validated in the external cohort (5-year DFS 0.65 vs. 0.72, p < 0.01; sensitivity of stage N3 increased from 14.0 % to 41.9 % for disease recurrence).

CONCLUSION

Results from two centre cohorts confirmed that the radiological advanced ENE should be considered as a criterion for stage N3 disease in NPC.

The feasibility of level Ib-sparing intensity-modulated radiation therapy in patients with nasopharyngeal carcinoma and high-risk factors classified based on the International Guideline

BACKGROUND AND PURPOSE

To examine the feasibility of level Ib-sparing intensity-modulated radiation therapy (IMRT) in patients with nasopharyngeal carcinoma (NPC) who had high-risk factors classified based on the International Guideline (IG).

MATERIALS AND METHODS

We evaluated 961 non-metastatic NPC cases based on IG recommendations for prophylactic Ib irradiation. Four high-risk factors were used to categorise patients into three cohorts: A, B, and C. Propensity score matching was used to balance baseline characteristics in Cohort C, resulting in a matched Cohort C. Recurrence rates at level Ib and regional relapse-free survival (RRFS) rates were evaluated.

RESULTS

Among patients with negative Ib lymph nodes (LNs), 18, 54, 420, and 444 exhibited involvement of structures that drain to level Ib as the first echelon (FES), involvement of the submandibular gland (SMG), level II LNs with radiologic extranodal extension (rENE), and level II nodes with a maximal axial diameter (MAD) ≥ 2 cm, respectively. The recurrence rate was highest in Cohort A (11.1 %). Cohort B had no level Ib recurrence. In matched Cohort C, recurrence rates were low in both groups (Ib-sparing group: 0.6 % vs. Ib-covering group: 0.6 %, P > 0.999). No significant differences were observed in 5-year RRFS rates between the two groups in cohort A (p = 0.208), cohort B (p = 0.905), and matched cohort C (p = 0.423).

CONCLUSIONS

Level Ib-sparing IMRT could be performed safely for NPC patients with level II LNs who had rENE and/or MAD ≥ 2 cm. Further research should determine the necessity of level Ib prophylactic irradiation for patients with FES or SMG involvement.

Prognostic nomograms for nasopharyngeal carcinoma with nodal features and potential indication for N staging system: Validation and comparison of seven N stage schemes

PURPOSE

To identify the prognostic value of the nodal features, propose a nomogram-based N stage system and evaluate the performance of seven N stage schemes of nasopharyngeal carcinoma (NPC) patients.

METHODS

Data from 1638 non-distant metastatic NPC patients were used to develop nomograms predicting 3-year and 5-year overall survival (OS) and distant metastasis-free survival (DMFS). Based on nomogram and multivariate analyses, a new N-stage scheme was proposed. The performance of the nomogram-based N staging system was assessed against five newly proposed N staging systems and the current 8th N staging system using a quantitative model to compare hazard consistency, discrimination, outcome prediction, and sample size balance. The Kaplan-Meier method with log-rank tests was used to compare survival differences.

RESULTS

Nomograms to predict OS and DMFS were constructed using extranodal extension infiltrating the surrounding structures (ENEmax), maximal axial diameter (MAD), large retropharyngeal lymph nodes (RLN, minimal axial diameter > 1.5 cm), multiple central nodal necrosis (CNN), and total lymph node (LN) number and level. Multivariate analysis showed the independent prognostic value of ENEmax and MAD > 3 cm for all selected survival endpoints (p < 0.05). Large RLN and lower neck involvement were independently associated with OS (p < 0.05). We proposed using a large RLN and MAD > 3 cm as N2 factors, and ENEmax and lower neck involvement as N3 factors. Among the seven N-stage schemes, our nomogram-based N scheme and ENEmax to N3 scheme (ENE3) ranked in the top two in the overall comparison with the elevated outcome predicting value (highest c-index). However, between the N0, N1, N1, and N2 subgroups, the ENE3 scheme showed no difference in OS or DMFS (p > 0.05).

CONCLUSION

The predictive model highlighted the independent prognostic value of ENEmax, cervical lymph node, MAD, and large RLN, which can be used as criteria for future N staging.

Prognostic significance of cervical radiologic carotid artery invasion by lymph node on magnetic resonance imaging in nasopharyngeal carcinoma

PURPOSE

Carotid artery invasion (CAI) has been demonstrated to be an important prognosticator in some head and neck cancers. This study aimed to examine the prognostic value of radiologic CAI (rCAI) by cervical lymphadenopathy in nasopharyngeal carcinoma (NPC).

METHODS

NPC patients treated between January 2013 and December 2016 were included. Pre-treatment MRIs were reviewed for cervical rCAI according to the radiologic criteria. Univariate and multivariate models were constructed to assess the association between cervical rCAI and clinical outcomes. A new N classification system was proposed and compared to the 8th AJCC system.

RESULTS

The percentage of patients with MRI-positive lymph nodes was 84.7% (494/583), of whom cervical rCAI cases accounted for 42.3% (209/494). Cervical rCAI was associated with significantly poorer OS, DFS, DFFS and RFFS compared to non-rCAI (P < 0.05). Multivariate analyses confirmed that cervical rCAI was an independent prognosticator for DFS and DFFS, surpassing other nodal features, such as laterality, size, cervical node necrosis (CNN) and radiologic extranodal extension (rENE), while location of positive LNs remained independently associated with OS, DFS and DFFS. We propose a refined N classification: New_N1: upper neck LNs only without cervical rCAI; New_N2: upper neck LNs only with cervical rCAI; New_N3: upper and lower LNs. The proposed classification broadened the differences in OS, DFS and DFFS between N1 and N2 disease, and achieved a higher c-index for DFS and DFFS.

CONCLUSIONS

Cervical rCAI was an independent unfavorable indicator of NPC. Compared to the AJCC system, the proposed N category showed satisfactory stratification between N1 and N2 disease, and better prediction of distant metastasis and disease failure.

Post-induction lymph node delineation in nasopharyngeal cancer: A single-center experience

BACKGROUND

We routinely delineate the gross tumor volume (GTV) for the lymph nodes (LN) based on post-induction chemotherapy (IC) MRI in nasopharyngeal carcinoma (NPC). Herein, we investigated the sufficiency of this method, particularly in high-risk LNs.

METHODS

Eighty-one LNs with a high-risk of clinical extranodal extension and/or ≥3-cm diameter in 58 patients were evaluated. A new GTV covering the pre-IC LN volume was delineated for each LN.

RESULTS

The median volume reduction was 72.5% for the GTV and 53.1% for the planning target volume. After a median 43 months, the overall LN local control rate was 97.5%. The 2- and 5-year LN recurrence-free survival, overall survival, and disease-free survival rate was 88.3% and 84.4%, 92.5% and 85.1%, and 86.8% and 79.2%, respectively.

CONCLUSION

IC yields a significant reduction in nodal target volumes, and post-IC nodal volume-based radiotherapy provides excellent LC in NPC, even in high-risk LNs.

The prognostic value of the ratio of standard uptake value of lymph node to primary tumor before treatment of locally advanced nasopharyngeal carcinoma

BACKGROUND

To evaluate the prognostic value of the ratio of the standard uptake value of the lymph node and primary tumor before the treatment of locally advanced nasopharyngeal carcinoma and examine the prognostic value of the tumor metabolic parameters (SUVmax_, MTV, and TLG) of the lymph node and primary tumor of locally advanced nasopharyngeal carcinoma.

METHODS

A total of 180 patients with locally advanced nasopharyngeal carcinoma diagnosed pathologically from January 1, 2016 to December 31, 2018 were selected, and the MEDEX system was used to automatically delineate the SUVmax, MTV, and TLG of the lymph node metastases and nasopharyngeal carcinoma primary tumor. In addition, the ratio of LN-SUVmax (SUVmax of the lymph node metastases) to T-SUVmax (SUVmax of the nasopharyngeal carcinoma primary tumor) was calculated, and a ROC curve was drawn to obtain the best cut-off value. Kaplan-Meier and Cox regression models were used for survival and multivariate analyses, respectively.

RESULTS

The median follow-up period for participants was 32 (4-62) months. Univariate analysis showed that age (P = 0.013), LN-SUVmax (P = 0.001), LN-TLG (P = 0.007) and NTR (P = 0.001) were factors influencing the overall survival (OS). Factors affecting local progression-free survival (LPFS) were LN-SUVmax (P = 0.005), LN-TLG (P = 0.003) and NTR (P = 0.020), while clinical stage (P = 0.023), LN-SUVmax (P = 0.007), LN-TLG (P = 0.006), and NTR (P = 0.032) were factors affecting distant metastasis-free survival (DMFS). Multivariate analysis showed that NTR was an independent influencing factor of OS (HR 3.00, 95% CI 1.06-8.4, P = 0.038), LPFS (HR 3.08, 95% CI 1.27-7.50, P = 0.013), and DMFS (HR 1.84, 95% CI 0.99-3.42, P = 0.054). Taking OS as the main observation point, the best cut-off point of NTR was 0.95. Kaplan-Meier results showed that the 3-year OS (97.0% vs 85.4%, χ² = 11.25, P = 0.001), 3-year LPFS (91.3% vs 82.1%, χ² = 4.035, P = 0.045), and 3-year DMFS (92.3% vs 87.9%, χ² = 4.576, P = 0.032) of patients with NTR < 0.95 were higher than those with NTR > 0.95.

CONCLUSIONS

High NTR before treatment indicates a poor prognosis for patients with nasopharyngeal carcinoma. This can serve as a reference value for the reasonable treatment and prognosis monitoring of such patients.

The role of radiologic extranodal extension in predicting prognosis and chemotherapy benefit for T1-2 N1 nasopharyngeal carcinoma: A multicenter retrospective study

BACKGROUND AND PURPOSE

This multicenter retrospective study aimed to investigated the prognostic value of unequivocal radiologic extranodal extension (rENE) and the efficacy of chemotherapy for stage T1-2 N1 nasopharyngeal carcinoma (NPC) in the IMRT era.

MATERIALS AND METHODS

We included 1,082 patients treated in 2005-2017 from three centers. rENE was recorded as G1 (coalescent nodal mass comprising ≥ 2 inseparable nodes) or G2 (invading beyond perinodal fat to frankly infiltrate adjacent structures). Multivariable analysis (MVA) evaluated the prognostic value of rENE. The value of chemotherapy was assessed in rENE-positive (rENE + ) and rENE-negative (rENE - ) subset separately.

RESULTS

Centers 1, 2, and 3 had 139/515 (27.0 %), 100/365 (27.4 %), and 43/202 (21.3 %) cN + patients with rENE, respectively. Compared to rENE-, rENE + patients had a worse distant metastasis-free survival (DMFS) and overall survival (OS) (all p < 0.001). MVA confirmed the prognostic of both G1-rENE and G2-rENE for distant metastasis [G1: hazard ratio (HR): 2.933, G2: HR: 6.942, all p < 0.001] and death (G1: HR: 1.587, p = 0.040; G2: HR: 6.162, p < 0.001). There was no significant difference for DMFS and OS between chemo-radiotherapy and radiotherapy alone in rENE + and rENE - groups (all p > 0.1). However, rENE + patients with a cumulative cisplatin/nedaplatin dose (CCND) of > 160 mg/m² had an improved DMFS (p = 0.033) but no OS (p = 0.197).

CONCLUSION

Unequivocal rENE is prognostic in patients with T1-2 N1 NPC. Addition of chemotherapy to radiotherapy did not affect DMFS and OS in rENE - patients. Chemotherapy with a CCND of > 160 mg/m² improved DMFS in rENE + patients.

Neck level Ib-sparing versus level Ib-irradiation in intensity-modulated radiotherapy for the treatment of nasopharyngeal carcinoma with high-risk factors: A propensity score-matched cohort study

AIM

Level Ib lymph nodes metastasis is rare in nasopharyngeal carcinoma (NPC). We aimed to evaluate the feasibility of sparing level Ib-irradiation in NPC patients with high-risk factors.

MATERIALS AND METHODS

Four hundred forty-three NPC patients with radiologic extranodal extension (rENE) or level II lymph node maximal axial diameter (MAD) ≥ 20 mm treated by intensity-modulated radiotherapy (IMRT) between 2009 and 2012 were included in this study. Propensity score matching (PSM) was applied to balance potential prognostic factors (including age, sex, T and N stage, pretreatment EBV DNA level, and level II rENE and MAD) between patients who received and omitted level Ib irradiation. Kaplan-Meier analysis and the log-rank test were used to compare regional survival outcomes.

RESULTS

PSM resulted in 169 matched pairs of eligible patients. The median follow-up period was 119 months in the matched cohort. The number of level Ib failure in the level Ib-sparing and level-Ib irradiation groups were 3/169 (1.8 %) vs 2/169 (1.2 %), P > 0.999. And the 5-year regional relapse-free survival (RRFS) rates of the two groups were 88.4 % vs 92.6 %, respectively. After PSM, RRFS (hazard ratio [HR]: 1.508, 95 % confidence interval [CI]: 0.762-2.986, P = 0.239), OS (HR: 1.219, 95 % CI: 0.754-1.972, P = 0.418), distant metastasis-free survival (DMFS) (HR: 1.605, 95 % CI: 0.900-2.863, P = 0.109), and local relapse-free (LRFS) (HR: 0.956, 95 % CI: 0.436-2.095, P = 0.910) were similar in the two arms. The incidence of grade ≥ 1 dry mouth after 5 years was higher in the level Ib-irradiation group (27.5 % vs 16.5 %, P = 0.029). However, the incidences of grade 3-4 late toxicities were similar between the two groups.

CONCLUSION

Neck level Ib-sparing appears to be safe and feasible in NPC patients with rENE or level II MAD ≥ 20 mm and negative level Ib lymph nodes. Compared with cervical level Ib-irradiation, omission of irradiation to level Ib provides less dry mouth symptom.

Feasibility and safety of neck level IB-sparing radiotherapy in nasopharyngeal cancer: a long-term single institution analysis

PURPOSE

Nasopharyngeal cancer (NPC) has a higher prevalence of regional nodal metastasis than other head and neck cancers; however, level IB lymph node involvement is rare. We evaluated the safety and feasibility of level IB-sparing radiotherapy (RT) for NPC patients.

MATERIALS AND METHODS

We retrospectively reviewed 236 patients with NPC who underwent definitive intensity-modulated RT with or without chemotherapy between 2004 and 2018. Of them, 212 received IB-sparing RT, and 24 received non-IB-sparing RT. We conducted a propensity score matching analysis to compare treatment outcomes according to IB-sparing status. In addition, dosimetric analysis of the salivary glands was performed to identify the relationship between xerostomia and the IB-sparing RT.

RESULTS

The median follow-up duration was 78 months (range, 7 to 194 months). Local, regional, and distant recurrences were observed in 11.9%, 6.8%, and 16.1% of patients, respectively. Of the 16 patients with regional recurrence, 14 underwent IB-sparing RT. The most common site categorization of regional recurrence was level II (75%), followed by retropharyngeal lymph nodes (43.8%); however, there was no recurrence at level IB. In the matched cohorts, IB-sparing RT was not significantly related to treatment outcomes. However, IB-sparing RT patients received a significantly lower mean ipsilateral and contralateral submandibular glands doses (all, p < 0.001) and had a lower incidence of chronic xerostomia compared with non-IB-sparing RT patients (p = 0.006).

CONCLUSION

Our results demonstrated that IB-sparing RT is sufficiently safe and feasible for treating NPC. To reduce the occurrence of xerostomia, IB-sparing RT should be considered without compromising target coverage.

Prognostic value of quantitative cervical nodal necrosis burden on MRI in nasopharyngeal carcinoma and its role as a stratification marker for induction chemotherapy

OBJECTIVES

This study aimed to assess the prognostic value of quantitative cervical nodal necrosis (CNN) burden in N staging risk stratification in patients with nasopharyngeal carcinoma.

METHODS

Univariate and multivariate Cox regression models evaluated the association between lymph node variables based on MRI images and survival. Revisions for the N classification system were proposed and compared to the 8th edition AJCC staging system using Harrell's concordance index (C-index). The survival outcomes of induction chemotherapy plus concurrent chemoradiotherapy (CCRT) and CCRT alone in patients with multiple CNNs were compared.

RESULTS

In 1319 patients enrolled, CNN was not an independent prognostic factor for the main survival outcomes, but multiple CNNs (three or more necrotic nodes) were independent prognostic factors for distant metastasis-free survival (DMFS) (adjusted hazard ratio [HR], 2.05; p = 0.020) and progression-free survival (PFS) (HR, 1.78; p = 0.004), surpassing other nodal variables. On upgrading patients with multiple CNNs to revised N3 disease, the proposed N staging widened the differences in DMFS and PFS between N2 and N3 disease. The overall survival of patients with multiple CNNs who received CCRT plus induction chemotherapy was improved compared to that of those who received CCRT alone (76.1% vs. 55.7%; adjusted p = 0.030).

CONCLUSIONS

Upgrading patients with multiple CNNs to stage N3 may improve prognostication of the current AJCC staging system. Multiple CNNs might be a potential marker for stratifying patients who would benefit from induction chemotherapy.

KEY POINTS

• Quantitatively assessed the prognostic value of CNN burden in patients with NPC. • Upgrading patients with multiple CNNs to stage N3 may improve prognostication. • Multiple CNNs may be used as a stratification marker for induction chemotherapy.

Effect of Radiotherapy Alone vs Radiotherapy With Concurrent Chemoradiotherapy on Survival Without Disease Relapse in Patients With Low-risk Nasopharyngeal Carcinoma: A Randomized Clinical Trial

IMPORTANCE

Concurrent chemoradiotherapy has been the standard treatment for stage II nasopharyngeal carcinoma (NPC) based on data using 2-dimensional conventional radiotherapy. There is limited evidence for the role of chemotherapy with use of intensity-modulated radiation therapy (IMRT).

OBJECTIVE

To assess whether concurrent chemotherapy can be safely omitted for patients with low-risk stage II/T3N0 NPC treated with IMRT.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter, open-label, randomized, phase 3, noninferiority clinical trial was conducted at 5 Chinese hospitals, including 341 adult patients with low-risk NPC, defined as stage II/T3N0M0 without adverse features (all nodes <3 cm, no level IV/Vb nodes; no extranodal extension; Epstein-Barr virus DNA <4000 copies/mL), with enrollment between November 2015 and August 2020. The final date of follow-up was March 15, 2022.

INTERVENTIONS

Patients were randomly assigned to receive IMRT alone (n = 172) or concurrent chemoradiotherapy (IMRT with cisplatin, 100 mg/m2 every 3 weeks for 3 cycles [n = 169]).

MAIN OUTCOMES AND MEASURES

The primary end point was 3-year failure-free survival (time from randomization to any disease relapse or death), with a noninferiority margin of 10%. Secondary end points comprised overall survival, locoregional relapse-free survival, distant metastasis-free survival, adverse events, and health-related quality of life (QOL) measured by the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire (QLQ-C30; range, 0-100 points; minimum clinically important difference ≥10 for physical function, symptom control, or health-related QOL; higher score indicates better functioning and global health status or worse symptoms).

RESULTS

Among 341 randomized patients (mean [SD] age, 48 [10] years; 30% women), 334 (98.0%) completed the trial. Median follow-up was 46 months (IQR, 34-58). Three-year failure-free survival was 90.5% for the IMRT-alone group vs 91.9% for the concurrent chemoradiotherapy group (difference, -1.4%; 1-sided 95% CI, -7.4% to ∞; P value for noninferiority, <.001). No significant differences were observed between groups in overall survival, locoregional relapse, or distant metastasis. The IMRT-alone group experienced a significantly lower incidence of grade 3 to 4 adverse events (17% vs 46%; difference, -29% [95% CI, -39% to -20%]), including hematologic toxicities (leukopenia, neutropenia) and nonhematologic toxicities (nausea, vomiting, anorexia, weight loss, mucositis). The IMRT-alone group had significantly better QOL scores during radiotherapy including the domains of global health status, social functioning, fatigue, nausea and vomiting, pain, insomnia, appetite loss, and constipation.

CONCLUSIONS AND RELEVANCE

Among patients with low-risk NPC, treatment with IMRT alone resulted in 3-year failure-free survival that was not inferior to concurrent chemoradiotherapy.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02633202.

Prognostic value of cervical nodal necrosis on staging imaging of nasopharyngeal carcinoma in era of intensity-modulated radiotherapy: a systematic review and meta-analysis

Purposes

To systematically review and perform meta-analysis to evaluate the prognostic value of cervical nodal necrosis (CNN) on the staging computed tomography/magnetic resonance imaging (MRI) of nasopharyngeal carcinoma (NPC) in era of intensity-modulated radiotherapy.

Methods

Literature search through PubMed, EMBASE, and Cochrane Library was conducted. The hazard ratios (HRs) with 95% confidence intervals (CIs) of CNN for distant metastasis-free survival (DMFS), disease free survival (DFS) and overall survival (OS) were extracted from the eligible studies and meta-analysis was performed to evaluate the pooled HRs with 95%CI.

Results

Nine studies, which investigated the prognostic values of 6 CNN patterns on MRI were included. Six/9 studies were eligible for meta-analysis, which investigated the CNN presence/absence in any nodal group among 4359 patients. The pooled unadjusted HRs showed that the CNN presence predicted poor DMFS (HR =1.89, 95%CI =1.72-2.08), DFS (HR =1.57, 95%CI =1.08-2.26), and OS (HR =1.87, 95%CI =1.69-2.06). The pooled adjusted HRs also showed the consistent results for DMFS (HR =1.34, 95%CI =1.17-1.54), DFS (HR =1.30, 95%CI =1.08-1.56), and OS (HR =1.61, 95%CI =1.27-2.04). Results shown in the other studies analysing different CNN patterns indicated the high grade of CNN predicted poor outcome, but meta-analysis was unable to perform because of the heterogeneity of the analysed CNN patterns.

Conclusion

The CNN observed on the staging MRI is a negative factor for NPC outcome, suggesting that the inclusion of CNN is important in the future survival analysis. However, whether and how should CNN be included in the staging system warrant further evaluation.

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.

The prognostic value of radiologic extranodal extension in nasopharyngeal carcinoma: Systematic review and meta-analysis

OBJECTIVES

The prognostic value of radiologic extranodal extension (rENE) in nasopharyngeal carcinoma remains controversial. In this study, a meta-analysis was performed to assess the prognostic value of ungraded rENE and unambiguous advanced rENE.

METHODS

A literature search through PubMed, Cochrane Library, EMBASE and manual searches was conducted until May 2021. The adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) of overall survival and distant metastasis-free survival were extracted and pooled.

RESULTS

Nine eligible studies were published between 2012 and 2021. The pooled patient number was 7532 (range 61-1887). Seven studies were eligible for the analysis of ungraded rENE, while 3 studies were eligible for unambiguous advanced rENE. The results showed that ungraded rENE was associated with worse overall survival (HR 1.85, 95% CI 1.04-3.27) and significantly associated with worse distant metastasis-free survival (HR 2.07, 95% CI 1.36-3.13). On the other hand, unambiguous advanced rENE was significantly associated with worse overall survival (HR 2.62, 95% CI 2.12-3.25) and worse distant metastasis-free survival (HR 3.14, 95% CI 1.85-5.33).

CONCLUSIONS

In nasopharyngeal carcinoma, both ungraded and unambiguous advanced rENE are significant prognosticators of overall survival and distant metastasis-free survival. More prospective studies are required to determine its role in risk stratification or clinical staging.

Maximal lymph nodal diameter on N stage of nasopharyngeal carcinoma

To assess the maximal lymph nodal diameter on the 8th edition American Joint Committee on Cancer staging system of nasopharyngeal carcinoma (NPC).This study extracted NPC patients between 2004 and 2016 in the Surveillance, Epidemiology, and End Results database. Included patients were divided into 3 groups: ≤3 cm, >3-6 cm, and >6 cm based on the maximal lymph nodal diameter. Cumulative survival curves of 5-year overall survival (OS) and cancer-specific survival (CSS) were calculated using the Kaplan-Meier method between the 3 groups.The 5-year OS (64.0% vs 59.3%, P = .240) and CSS (71.8% vs 67.0%, P = .242) of ≤3 cm and >3-6 cm groups were not different. In contrast, the 5-year OS and CSS were different between >6 cm and ≤3 cm groups, and between >6 cm and >3-6 cm groups. The stratified hazard ratio of OS and CSS was 1.75 (95% confidence interval: 1.25-2.45; P = .001) and 1.77 (95% confidence interval: 1.20-2.60; P = .004) for the >6 cm group in the multivariate regression analysis.It is reasonable that the maximal lymph nodal diameter with >6 cm is classified as stage N3 of the 8th edition American Joint Committee on Cancer staging system for NPC.

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.

Prognostic Significance of Radiologic Extranodal Extension in Nasopharyngeal Cancer

OBJECTIVE

The aim of the present study was to evaluate the prognostic value of radiologic extranodal extension (rENE) in patients with nasopharyngeal cancer.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary university hospital.

METHODS

We identified patients with nasopharyngeal cancer and lymph node metastasis who underwent pretreatment neck computed tomography or magnetic resonance imaging and evaluated rENE from the involved lymph node. Univariate Kaplan-Meier and multivariate Cox regression analyses were used to compare rENE+ and rENE- groups for local regional relapse-free survival, distant metastasis-free survival, and overall survival.

RESULTS

Of 61 cases, 24 (39.3%) were rENE+ and 37 (60.7%) were rENE-. The median follow-up was 65.5 months. The 5-year distant metastasis-free survival and overall survival rates were lower in the rENE+ group than the rENE- group (70.8% vs 89.2%, P = .016; 66.7% vs 89.2%, P = .01, respectively). Differences in locoregional control between the groups were not significant (P = .18). The 5-year rates for local regional relapse-free survival were 87.5% for rENE+ and 91.9% for rENE-. In multivariate analysis, the presence of rENE was a significant independent adverse prognostic factor for distant metastasis-free survival and overall survival.

CONCLUSIONS

We showed that rENE is an independent prognostic factor for poor distant control and survival in patients with nasopharyngeal cancer.

Contemporary management of the neck in nasopharyngeal carcinoma

Up to 85% of the patients with nasopharyngeal carcinoma present with regional nodal metastasis. Although excellent nodal control is achieved with radiotherapy, a thorough understanding of the current TNM staging criteria and pattern of nodal spread is essential to optimize target delineation and minimize unnecessary irradiation to adjacent normal tissue. Selective nodal irradiation with sparing of the lower neck and submandibular region according to individual nodal risk is now emerging as the preferred treatment option. There has also been continual refinement in staging classification by incorporating relevant adverse nodal features. As for the uncommon occurrence of recurrent nodal metastasis after radiotherapy, surgery remains the standard of care.

Assessment Criteria and Clinical Implications of Extranodal Extension in Head and Neck Cancer

Tumor breaching the capsule of a lymph node is termed extranodal extension (ENE). It reflects aggressiveness of a tumor, creates anatomic challenges for disease clearance, and increases the risk of distant metastasis. Extranodal extension can be assessed on a pathology specimen, by radiology studies, and by clinical examination. Presence of ENE in a pathology specimen has long been considered a high-risk feature of disease progression and would ordinarily benefit from the addition of chemotherapy to adjuvant radiotherapy. Although the eighth edition of the Union for International Cancer Control/American Joint Committee on Cancer stage classification dichotomizes pathologic ENE according to its presence or absence, emerging evidence suggests that the extent of a pathologic ENE may provide additional value for risk stratification to guide adjuvant therapy. Recent data suggest that the prognostic importance of pathologic ENE is also applicable for HPV-associated head and neck squamous cell carcinoma. In addition, compelling data demonstrate that indisputable radiologic ENE is a powerful risk stratification tool to identify patients at high risk for treatment failure, especially distant metastasis, applicable for both HPV-positive and HPV-negative head and neck squamous cell carcinoma. However, the definition and taxonomy of radiologic ENE requires standardization. The goal of this review is to clarify the contemporary understanding of the prognostic implications of ENE in head and neck squamous cell carcinoma, present the nuances of what is presently known and unknown, and elucidate how to classify ENE pathologically and radiologically with an understanding of the strengths and weaknesses of each approach. Finally, with the development of several risk stratification methods, the relative role of ENE and other prognostic schema will be explored.

Unambiguous advanced radiologic extranodal extension determined by MRI predicts worse outcomes in nasopharyngeal carcinoma: Potential improvement for future editions of N category systems

BACKGROUND AND PURPOSE

To explore the prognostic value of different radiologic extranodal extension (rENE) grades and their potential improvement for the 8th edition N category in nasopharyngeal carcinoma (NPC).

MATERIALS AND METHODS

From 2009 to 2013, a cohort of 1887 patients with NPC was retrospectively enrolled and randomized to the training (n = 955) and validation (n = 932) groups. rENE was categorized as follows: grade 0, nodes without rENE; grade 1, nodes with rENE infiltrating the surrounding fat only; grade 2, matted nodes; grade 3, nodes with rENE infiltrating adjacent structures.

RESULTS

The percentage of patients with MRI-positive cervical nodes was 66.5% (1254/1887), of whom grade 0, 1, 2 and 3 rENE cases accounted for 33.2% (416/1254), 14.9% (187/1254), 36.5% (458/1254) and 15.4% (193/1254), respectively. The kappa coefficients for the inter-rater and intra-rater assessments were 0.63, 0.51, 0.65 and 0.93, and 0.76, 0.69, 0.72 and 1.0 in grade 0, 1, 2 and 3 rENE, respectively. Grade 3 rENE rather than grades 0-2 rENE was an independent unfavorable predictor of overall survival and disease-free survival (P < 0.001). Recursive partitioning analysis was applied to refine the N category: eN0 (N0), eN1 (N1 without grade 3), eN2 (N2 without grade 3), and eN3 (N1/N2 with grade 3, N3). Compared to the current system, the proposed N category performed better in hazard consistency, hazard discrimination, sample size balance and outcome prediction.

CONCLUSION

Grade 3 rENE was an independent unfavorable indicator of NPC. Upstaging patients in N1-2 with grade 3 rENE to N3 led to a superior prognostic performance.

Development and Validation of Prognostic Nomograms Based on Gross Tumor Volume and Cervical Nodal Volume for Nasopharyngeal Carcinoma Patients With Concurrent Chemoradiotherapy

PURPOSE

Our study aimed to establish and validate prognostic nomograms based on gross tumor volume (GTV) and cervical nodal volume (CNV) for nasopharyngeal carcinoma (NPC) patients treated with two cycles of concurrent chemoradiotherapy (CCRT).

METHODS

From 2012 to 2015, 620 eligible patients who received radical treatment at the Cancer Hospital of Shantou University Medical College were recruited for a nomogram study. Variables were determined in a training set of 463 patients from 2012 to 2014 by X-tile analysis, univariate and multivariate Cox proportional hazard analyses, and the least absolute shrinkage and selection operator (LASSO). Another cohort of 157 patients in 2015 was validated with bootstrap resampling. The concordance index (C-index) and calibration curves were applied to assess its predictive discriminative and accuracy ability, while decision curve analysis (DCA), X-tile analysis and Kaplan-Meier curve for clinical application.

RESULTS

Independent prognostic variables for overall survival (OS) were age, GTV, CNV, cranial nerve, positive cervical lymph node laterality below the caudal border of cricoid cartilage (LNBC), and were selected for the nomogram. Optimal prognostic factors including Karnofsky performance status (KPS), age, GTV, CNV, LNBC were incorporated in the nomogram for progression-free survival (PFS). In the training set, the C-index of our nomograms for OS and PFS were 0.755 (95% CI, 0.704 to 0.807) and 0.698 (95% CI, 0.652 to 0.744). The calibration curve showed good agreement between nomogram-predicted and actual survival. DCA indicated that our nomograms were of clinical benefit.

CONCLUSION

Our nomograms are capable of effective prognostic prediction for patients with NPC.

Prognosis of Extracapsular Spread of Cervical Lymph Node Metastases in Nasopharyngeal Carcinoma

Purpose

This study aims to identify the prognosis of the extracapsular spread (ECS) of cervical lymph node metastases in nasopharyngeal carcinoma (NPC).

Materials and Methods

Patients with NPC were extracted from the Surveillance, Epidemiology, and End Results (SEER) database from 2004 to 2016. Pathologically confirmed World Health Patients with World Health Organization types I, II, and III NPC with complete ECS data of cervical lymph node metastases were investigated. The included patients were divided into non-ECS and ECS groups. The 10-year overall survival (OS) and cancer-specific survival (CSS) were compared between the two groups using the Kaplan-Meier method and propensity score matching analyses.

Results

A total of 625 patients were included. The ECS group included 99 (15.84%) patients. The non-ECS group included 526 (84.16%) patients. The 10-year OS (50.2 vs. 35.8%; P < 0.001) and CSS (64.8 vs. 45.7%; P < 0.001) were better in the non-ECS group than in the ECS group in the unmatched cohort. Propensity score matching analyses revealed favorable 10-year OS (52.7 vs. 35.8%; P = 0.008) and CSS (61.2 vs. 45.7%; P = 0.008) in the non-ECS group with respect to the ECS group. Age, sex, race, AJCC stage, and ECS (hazard ratio (HR) = 1.71, 95% confidence interval (CI), 1.14–2.57, P = 0.010) were independent prognostic factors for OS. Age, sex, AJCC stage, and ECS (HR = 1.91; 95% CI, 1.21–3.01; P = 0.005) were independent prognostic factors for CSS.

Conclusion

This study indicated that ECS is a prognostic risk factor for NPC. Further studies should be performed to verify the results due to the limitations of the SEER database.

Development and Validation of a Prognostic Nomogram Based on Residual Tumor in Patients With Nondisseminated Nasopharyngeal Carcinoma

Objectives:

To investigate the prognostic value of residual tumor based on Magnetic resonance imaging(MRI) and establish an effective prognostic nomogram model referring to clinical,pathological and other related factors for predicting prognosis in nasopharyngeal carcinoma.

Methods:

Overall, 538 patients with non-metastatic, histologically-confirmed nasopharyngeal carcinoma were retrospectively examined. Data from 397 patients were used for the construction and validation of a nomogram based on the presence of residual tumor. A concordance index (C-index) was employed to assess the predictive accuracy and discriminative ability of the nomogram.

Results:

The 3-year survival rates in the non-residual and residual tumor cohorts were as follows: progression-free survival, 73.4% vs. 61.0%, P = 0.009; locoregional recurrence-free survival, 81.9% vs. 72.0%, P = 0.02; and distant metastasis-free survival, 80.7% vs. 73.5%, P = 0.11. Nine significant factors were included in the nomogram model. The calibration curve for the probability of progression-free survival showed that the nomogram-based predictive values had good concordance with the actual observations.

Conclusion:

The results showed that the patients in the residual tumor cohorts had a worse prognosis.The proposed nomogram may predict the prognosis and guide clinical decision-making concerning local residual tumors in nasopharyngeal carcinoma patients. Patients with a high risk of progression require more timely and aggressive treatment.

Prognostic Value of Nodal Matting on MRI in Nasopharyngeal Carcinoma Patients

BACKGROUND

Nodal (N) stage is one of the most important predictors for distant metastasis in nasopharyngeal carcinoma (NPC) patients. It may ignore potentially useful nodal features, such as nodal matting (three or more lymph nodes abutting together with the absence of intervening fat planes).

PURPOSE

To explore the prognostic value of nodal matting in NPC patients and construct a nomogram with nodal matting for predicting distant metastasis-free survival (DMFS).

STUDY TYPE

Retrospective.

POPULATION

In all, 792 NPC patients treated with intensity modulated radiation therapy from 2010 to 2013 were enrolled with 2:1 training (n = 527) and validation (n = 65) cohorts.

FIELD STRENGTH/SEQUENCE

T₁ - and T₂ -weighted imaging at 1.5 or 3.0T.

ASSESSMENT

Nodal matting and other nodal characteristics were assessed with MRI. MR images were evaluated separately by three radiologists. The association between nodal matting and DMFS was analyzed.

STATISTICAL TESTS

Univariate and multivariate analyses were performed using the Cox proportional hazards regression model. Nomograms were constructed from a multivariate logistic regression model with and without nodal matting. The predictive accuracy and discriminative ability of the nomograms were determined by concordance index (C-index) and calibration curves. The results were validated using bootstrap resampling and validation cohort.

RESULTS

The incidence of nodal matting was 24.6% (195/792) in all patients. In the training cohort, nodal matting was independently associated with DMFS (hazard ratio [HR] = 1.97 [1.05-3.69], P < 0.05). N1 patients with nodal matting had worse DMFS than N1 patients without (P < 0.05). However, no significant difference was observed when comparing N1 patients with nodal matting to N2 patients (P = 0.464). The C-index of the nomogram with nodal matting was higher than the nomogram without (0.717 vs. 0.699, P = 0.084).

DATA CONCLUSION

Nodal matting was an independent prognostic factor for DMFS in NPC patients. It may help to select patients at high risk of distant metastasis.

Prognostic value of MRI-determined cervical lymph node size in nasopharyngeal carcinoma

Objectives

To investigate the prognostic value of magnetic resonance imaging (MRI)‐determined cervical lymph node (CLN) size in nasopharyngeal carcinoma (NPC).

Methods

We retrospectively reviewed 2066 patients with NPC treated with intensity‐modulated radiotherapy, and randomly divided them into two groups, in a 1:1 ratio. One group was used for training (the training group), and the other one was for internal validation (the validation group). All patients had undergone MRI examination and the maximal axial diameters (MAD) of the axial plane of all positive nodes had been measured and recorded.

Results

Of 683 patients with CLN metastases in the training group (n = 1033), MAD = 4 cm was associated with worse OS (64.7% vs 84.6%, P < .001), DFS (55.9% vs 76.3%, P = .001), and DMFS (67.6% vs 86.1%, P = .001). Multivariate analysis showed that MAD = 4 cm was a significant negative prognostic factor for OS (HR = 2.058; P = .025), DFS (HR = 1.727; P = .049), and DMFS (HR = 2.034; P = .036). When MRI‐determined MAD = 4 cm was classified as N3 in the N classification, the OS, DFS, DMFS, and RRFS survival curves were well separated. The OS, DFS, DMFS, and RRFS concordance indexes were not statistically different between the proposed N staging system and the UICC/AJCC staging system in the training group, or between the training group and the validation group (all P = .05).

Conclusion

MAD = 4 cm on axial MRI slices can be recommended as a prognostic factor in future versions of the UICC/AJCC NPC staging system.

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

BACKGROUND AND PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Validation of Stage N3 of the Eighth Edition AJCC Staging System for Nasopharyngeal Carcinoma

OBJECTIVES

To validate stage nodal (N)3 of the 8th edition American Joint Committee on Cancer (AJCC) staging system for nasopharyngeal carcinoma (NPC).

METHODS

This retrospective cohort study extracted NPC patients from the Surveillance, Epidemiology, and End Results database between 2004 and 2016. Pathologically confirmed patients with complete data of level IV, N3a, and N3b lymph node metastasis were investigated. The included patients were divided into level IV, N3a, and N3b groups. Five-year overall survival (OS) and cancer-specific survival (CSS) were compared among the three groups.

RESULTS

A total of 693 patients were included: 285 (41.13%) patients in the level IV group, 124 (17.89%) patients in the N3a group, and 284 (40.98%) patients in the N3b group. The 5-year OS (57.1%, 55.0%, and 55.2%) and CSS (64.4%, 63.5%, and 64.4%) were not different among the level IV, N3a, and N3b groups. Multivariate regression analysis revealed that N stage was not an independent prognostic factor for OS (hazard ratio [HR] = 1.03, 95% confidence interval [CI]: 0.91-1.17; P = .65) or CSS (HR = 1.03, 95% CI: 0.89-1.19; P = .70).

CONCLUSION

Stage N3 of the 8th edition AJCC staging system for NPC is reasonable.

LEVEL OF EVIDENCE

III Laryngoscope, 131:535-540, 2021.

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.

An integrated model of the gross tumor volume of cervical lymph nodes and pretreatment plasma Epstein-Barr virus DNA predicts survival of nasopharyngeal carcinoma in the intensity-modulated radiotherapy era: a big-data intelligence platform-based analysis

Background:

Few studies have evaluated the prognostic value of the integrated model consisting of gross tumor volume of lymph nodes (GTVnd) and pretreatment plasma Epstein–Barr virus DNA (pre-EBV DNA) in nasopharyngeal carcinoma (NPC) patients.

Methods:

A well-established big-data intelligence platform with 10,126 NPC patients was used for a retrospective review. A total of 1500 cases with cervical nodal metastases but without distant metastases were randomly assigned to a training (n = 503) or test condition (n = 997) for analyses. The cut-off point for the GTVnd derived from the receiver operating characteristic (ROC) curve was combined with the published cut-off point for pre-EBV DNA to develop an integrated model by which patients were classified into four groups.

Results:

Both GTVnd and pre-EBV DNA were independent prognostic factors. Regardless of whether patients received induction chemotherapy (IC), the 5-year distant metastasis-free survival (DMFS) (69.5%) and overall survival (OS) (68.4%) were significantly worse in those with both a GTVnd >20 ml and pre-EBV DNA >2000 copies/ml (all p-values < 0.001). In patients with IC, all others had better 5-year DMFS and OS; in patients without IC, those with either a GTVnd >20 ml or pre-EBV DNA >2000 copies/ml had the medium 5-year DMFS and OS, while patients with neither of them had the best.

Conclusions:

The integrated GTVnd and pre-EBV DNA model not only predicted DMFS and OS in NPC patients effectively, but was an indicator of timely adjustment of therapeutic strategies for NPC patients, especially those completing IC.

Quantitative Metastatic Lymph Node Regions on Magnetic Resonance Imaging Are Superior to AJCC N Classification for the Prognosis of Nasopharyngeal Carcinoma

Purpose

Quantitative lymph node burden has been demonstrated to be a critical prognosticator in various malignancies, yet it was seldom explored in nasopharyngeal carcinoma (NPC). This study aimed to investigate the impact of the number of metastatic lymph node regions (LRN) on prognosis of NPC and to establish a new N classification system based on LRN.

Methods and Materials

The magnetic resonance images (MRI) of 354 nondisseminated NPC patients before radical treatment were retrospectively evaluated. The regions with positive lymph nodes (LNs) were quantified according to 2013 updated guidelines for neck node levels. Prognostic value of LRN on distant metastasis-free survival (DMFS) was analyzed using multivariable Cox model after adjusting for other nodal characteristics and therapeutic factors.

Results

LRN strongly correlated with the size, laterality, level, extracapsular extension (ECE), and necrosis of LNs. Risk of distant metastasis significantly escalated with increased LRN (P<0.001). 5-year DMFS for LRN 0-1, 2-6, and ⩾7 was 97.0%, 86.7%, and 69.7%, respectively. In multivariable Cox analysis, LRN (HR 2.45; 95% CI 1.55-3.88; P<0.001) and maximal LN diameter (MLD) >6cm (HR 4.11; 95% CI 2.23-7.56; P<0.001) were identified as independent predictors of DMFS. Laterality and level showed no prognostic significance when accounting for LRN. A novel N classification scheme was derived by recursive partitioning analysis based on LRN and MLD. Compared with the 7th and 8th edition of American Joint Committee on Cancer (AJCC) systems, the new stratification exhibited better accuracy in predicting survivals.

Conclusions

LRN is a promising quantitative predictor of survival in NPC, eclipsing other classic LN characteristics in prognostic value. The simplified N classification scheme with LRN and MLD is predictive and practical, thus warranting further validation in future.

A novel scoring model to predict benefit of additional induction chemotherapy to concurrent chemoradiotherapy in stage II-IVa nasopharyngeal carcinoma

OBJECTIVES

Induction chemotherapy (IC) is gaining recognition for the treatment of nasopharyngeal carcinoma (NPC). We aimed to develop a model to predict benefit from additional IC to concurrent chemoradiotherapy (CCRT).

MATERIALS AND METHODS

From an NPC-specific database, 7413 patients with stage II-IVa disease who received CCRT with or without IC were included. Distant metastasis-free survival (DMFS) was the primary outcome and benefit from IC was evaluated by adjusted hazard ratio. Interaction terms between IC and other prognostic factors were identified in multivariate Cox model, and IC benefit score (ICBS) was calculated based on β coefficients from the Cox model.

RESULTS

Nodal category, overall stage, and pre-treatment plasma Epstein-Barr virus DNA (log transformed as continuous variable) interacted with IC and determined ICBS. ICBS could discriminate patients who benefited differently from IC in terms of DMFS well, especially for patients with high and low ICBS. As for patients with medium ICBS, predictive performance of ICBS seemed reduced.

CONCLUSIONS

Based on the ICBS model, we proposed a decision-making process to help in clinical practice. Multi-institutional and prospective studies are warranted to further validate our findings.

The efficacy of induction chemotherapy in the treatment of stage II nasopharyngeal carcinoma in intensity modulated radiotherapy era

PURPOSE

To evaluate the efficacy of induction chemotherapy in the treatment of stage II nasopharyngeal carcinoma (NPC) in era of intensity modulated radiotherapy (IMRT).

METHODS AND MATERIALS

A total of 173 patients with American Joint Committee on Cancer (AJCC) 7th stage II NPC from two institutions were included. All patients were divided into two groups: induction chemotherapy + concurrent chemoradiotherapy group (ICRT) group and concurrent chemoradiotherapy group (CCRT). Induction chemotherapy was consisted of one to three cycles of cisplatin plus fluorouracil (PF) or paclitaxel plus cisplatin (TP). Concurrent chemotherapy included one to three cycles of cisplatin. We retrospectively assessed overall survival (OS), progression-free survival (PFS), locoregional failure free survival (LRFFS) and distant metastasis free survival (DMFS) in patients of both groups. T-test, Chi-square test, Kaplan-Meier methodology and Cox proportional hazards model were used to analyze.

RESULTS

With a median follow up of 64.7 months, no significant difference was found in grade 3-4 hematologic toxicity, liver dysfunction and renal impairment between ICRT and CCRT group. Univariable analyses shown adding induction chemotherapy to CCRT significantly decreased 5-year OS (87.9% vs 95.5%, P = 0.033), 5-year PFS (74.0% vs 86.1%, P = 0.035), 5-year LRFFS (80.0% vs 91.2%, P = 0.016), but there was no statistically significant difference in 5-year DMFS (87.1% vs 94.7%, P = 0.095). In multivariable analyses, we found the consistent results that induction chemotherapy was a negative factor associated with OS (HR of death = 3.768, 95% CI = 1.117-12.709; P = 0.032), PFS (HR of progression = 2.156, 95% CI = 1.060-4.386; P = 0.034), LRFFS (HR of locoregional relapse = 2.435, 95% CI = 1.009-5.874; P = 0.048) and also DMFS (HR of metastasis = 2.873, 95% CI = 1.005-8.211; P = 0.049), in stage II NPC patients.

CONCLUSION

In present study, we found that induction chemotherapy caused deleterious effect on stage II NPC patients. However, this is a retrospective study and the adverse effects of induction chemotherapy has not been previously reported. It warrants further investigation.

A novel N staging system for NPC based on IMRT and RTOG guidelines for lymph node levels: Results of a prospective multicentric clinical study

The present study aimed to investigate the cervical lymph node metastasis of nasopharyngeal carcinoma (NPC) and to establish a novel N staging standard for NPC, based on intensity modulated radiation therapy (IMRT) via a prospective multicenter clinical trial. Between January 2006 and December 2009, a total of 492 patients with NPC without distant metastasis were included in the present study. All patients were treated with IMRT. According to Radiation Therapy Oncology Group division standards, the present study proposed a novel N staging system following the review of magnetic resonance images in comparison with the 7th edition of Union for International Cancer Control/American Joint Committee on Cancer (UICC/AJCC) staging system. Retropharyngeal lymph nodes, cervical lymph node level and cervical lymph node laterality were independent prognostic factors used in multivariate analyses. According to the results of the risk variety, the present study suggested that the novel N staging system included: N0 (no lymph node metastasis), N1 [retropharyngeal or/and unilateral upper cervical (I, II, III, Va, VIIb, VIII, IX and X regions) lymph node metastasis], N2 [bilateral upper cervical (I, II, III, Va, VIIb, VIII, IX and X regions) lymph node metastasis] and N3 (lymph node metastasis in IVa and Vb regions and their lower regions). The novel N staging system proposed in the present study performs better in risk difference and distribution balance. Furthermore, the differences of 5-year curves of distant metastasis-free survival and overall survival had greater statistically significant differences compared with the 7th edition of the UICC/AJCC staging system. The present study suggested a novel N staging system for cervical lymph node metastasis of NPC, which may predict the prognosis of patients with NPC in a more objective and accurate way.

A new staging system for nasopharyngeal carcinoma based on intensity-modulated radiation therapy (IMRT)

Objective

This study is to establish a new staging system for nasopharyngeal carcinoma (NPC) based on the magnetic resonance imaging (MRI) and intensity-modulated radiation therapy (IMRT).

Methods

Totally 492 patients with nasopharyngeal carcinoma were included in this study. These patients were diagnosed by pathological detection (without distant metastasis) and underwent the initial treatment of IMRT. These patients were subjected to the staging with the International Union against Cancer/American Joint Committee on Cancer (UICC/AJCC) staging system. Survival rates were calculated by the Kaplan-Meier method. Log-rank test was used to calculate the single factor prognosis, and the COX risk model was used to analyze the multivariate prognosis.

Results

In these 492 patients, according to our recommended new T and N staging criteria, there were 290 cases of T1 and 202 cases of T2; there were 64 cases of N0, 159 cases of N1, 226 cases of N2, and 43 cases of N3. Univariate and multivariate analyses showed that the T and N staging combination parameters were independent prognostic factors, which affected the overall survival rates and tumor-free survival rates. According to risk difference and survival curve distribution, the following new clinical staging criteria were established: stage I (T1N0M0), stage II (T1N1M0 and T2N0M0), stage III (T1N2M0 and T2N1-2M0), stage IVa (T1-2N3M0), and stage IVb (TxNxM1).

Conclusion

A new staging system for NPC based on MRI and IMRT has been recommended, which provides valuable evidence for disease treatment and prognosis prediction.

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

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

Validation and comparison of the 7th and 8th edition of AJCC staging systems for non-metastatic nasopharyngeal carcinoma, and proposed staging systems from Hong Kong, Guangzhou, and Guangxi

OBJECTIVES

We aimed to validate and compare the 7th and 8th edition of AJCC staging systems for non-metastatic nasopharyngeal carcinoma, and proposed staging systems from Hong Kong, Guangzhou, and Guangxi.

MATERIALS AND METHODS

We retrospectively included 899 patients treated between November 5, 2002 and May 27, 2010. Separation and discrimination of each staging system in overall survival were primarily compared.

RESULTS

Compared with the 7th AJCC, the 8th AJCC and all proposed staging systems well separated across T-classification. T-classification from Guangzhou seemed to perform best in discrimination (C-index 0.6454), followed by the 8th AJCC (0.6451), the 7th AJCC (0.6386), Hong Kong (0.6376) and Guangxi (0.5889). For N-classification, no staging systems improved the weakness of the 7th AJCC in separating N2 and N1, except that suggestion from Guangzhou showed higher potential (P=0.096). Besides, N-classification from Guangzhou had a C-index of 0.6444, larger than that of the 8th AJCC (0.6235), the 7th AJCC (0.6179), Hong Kong (0.6175) and Guangxi (0.6175). Accordingly, stage group of staging system from Guangzhou showed higher discrimination (C-index 0.6839), compared with the 8th AJCC (0.6791), the 7th AJCC (0.6766), Hong Kong (0.6765) and Guangxi (0.6688), despite that stage I and II remained inseparable (P=0.322).

CONCLUSIONS

The 8th AJCC staging system appeared to be better than the 7th AJCC. But the proposed staging system from Guangzhou was more likely to improve the separation and discrimination abilities.

The feasibility analysis of omission of elective irradiation to level IB lymph nodes in low-risk nasopharyngeal carcinoma based on the 2013 updated consensus guideline for neck nodal levels

Background

Level IB metastasis is rare in nasopharyngeal carcinoma (NPC). The purpose of this study is to investigate the high-risk factors for level IB metastasis and evaluate the feasibility of omission of elective irradiation to level IB in the low-risk subgroups in NPC.

Methods

This retrospective study identified 532 patients with NPC treated by definitive radiation in our institution from 2009 to 2010. Level IB nodes were electively irradiated based on the physician’s decision. Diagnostic head and neck MRIs were reviewed. The involvements of nodal levels were evaluated according to 2013 updated guidelines of RTOG. The correlations of level IB metastasis and other factors were studied using Chi-square test and logistic regression model. Log-rank tests were used to compare survival rates. Cox proportional-hazards models were used to evaluate the effect of various factors. Patient-reported xerostomia was recoded in every follow-up and the extents of delayed xerostomia at 1 year post-radiation were compared between those with/without elective level IB irradiation.

Results

N stage, bilateral nodal metastasis, level II involvement, level IIA involvement, level IIA with multiple levels involvement, maximal axial diameter (MAD) of level IIA nodes > 20 mm, MAD of neck lymph nodes > 30 mm, necrosis of level IIA nodes, extracapsular spread of level IIA correlated with level IB metastasis by univariate analysis. In multivariate analysis (MVA), bilateral nodal involvement, MAD of level IIA nodes > 20 mm or extracapsular spread of level IIA nodes, were independent predictive factors for level IB metastasis. Patients without either these factors were denoted low-risk group and the rest high-risk group. Of the low-risk group, there was no significant difference of regional control and overall survival (OS) between those with or without elective irradiation. The percentage of level IB recurrence of those without elective irradiation was 0.46%. Elective level IB irradiation was not significant upon MVA both for regional control and OS. Of the high-risk group, elective level IB irradiation was marginal significant for regional control, but not for OS upon MVA. No regional recurrence located at level IB. Overall, omission of elective irradiation to level IB reduced the mean doses of submandibular glands, but did not improve patient-reported xerostomia.

Conclusion

For patients without high-risk factors of level IB metastasis, omission of elective level IB irradiation did not impair regional control and OS in NPC.

Electronic supplementary material

The online version of this article (doi:10.1186/s13014-017-0869-x) contains supplementary material, which is available to authorized users.

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

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

Prognostic significance of cystic lymph nodal metastasis in nasopharyngeal carcinoma

BACKGROUND

The purpose of this study was to determine the prevalence of cystic lymph nodal metastasis (CLNM) and its prognostic value in patients with nasopharyngeal carcinoma (NPC).

METHODS

A retrospective review was conducted on 257 patients with NPC, analyzing the presence of CLNM on MRI or CT scans. Oncologic outcomes were performed using the Kaplan-Meier analysis.

RESULTS

One hundred eleven patients (43.2%) had CLNM at diagnosis. Overall, patients with CLNM had a poorer disease-specific survival (DSS; P < .001) and overall survival (OS; P < .001) compared with patients without CLNM. When analyzed according to nodal status, CLNM was associated with a higher rate of distant metastasis recurrence (P = .007), a poorer DSS (P < .001), and a poorer OS (P < .001) among patients with N2 disease.

CONCLUSION

The prevalence of CLNM was 43.2%. In patients with N2 disease, the presence of CLNM was significantly associated with a poorer DSS, OS, and increased risk of distant metastasis recurrence.

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.