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Objectives Epstein-Barr virus (EBV)-positive cervical lymph node (CLN) metastasis of unknown primary origin is classified as nasopharyngeal carcinoma (NPC) T0 by the American Joint Committee on Cancer staging manual (8th edition). We aimed to investigate the possible primary sites and patterns of EBV-positive CLN metastases and to provide implications for the management of NPC T0 classification. Materials and methods We retrospectively reviewed 269 patients with newly diagnosed EBV-positive CLN metastatic disease who underwent EBV detection via EBV-encoded RNA in situ hybridization. Fifteen patients with unknown primary tumors underwent follow-up after initial treatment. Results In patients with EBV-positive CLNs, the most common primary sites after the nasopharynx (51.7%) were the salivary gland (24.5%), lung (7.8%), oropharynx (3.3%), nasal cavity/maxillary (3.3%), oral cavity (2.2%), orbit (1.1%), and liver (0.4%). No primary site was found in 15 patients (5.6%). For salivary gland malignancies, level II and I were the most frequently involved regions. Tumors arising from the lung or liver metastasized to the lower neck (level IV, V, and VI) rather than the upper neck. After initial treatment, 2/15 patients with EBV-positive CLNs of unknown primary exhibited primary NPC and oropharyngeal tumor, respectively. Further, even without prophylactic irradiation to the nasopharynx, only one of 13 unknown primary patients developed NPC. Conclusions The origins of EBV-positive CLNs may not be restricted to the nasopharynx alone, and are likely to involve the head and neck or non-head and neck regions. NPC T0 classification should be cautiously assigned to such tumors.

Objective In cancer trials, prior cancer is a common exclusion criterion. We evaluated the characteristics of prior cancer exclusion criteria in nasopharyngeal carcinoma (NPC) trials and determined its prognostic effect on patients with NPC. Methods We reviewed NPC trials for prior cancer exclusion criteria. Then we estimated the effect of prior cancer among NPC patients using the Surveillance, Epidemiology, and End Results database. Propensity score-matching was used to compensate for differences in baseline characteristics between patients with and without prior cancer. Results There were 109 clinical trials involving 10,437 patients; 49 trials (45%) excluded patients with prior cancer. Prior cancer exclusion was more common in recent or phase III trials. We identified 10,195 NPC patients; 6.2% had prior cancer. More than 70% of these cancers were in situ/localized/regional and diagnosed relatively close to the NPC diagnosis (median 3.3 years). Patients with certain prior cancer type (prostate, breast, gynecological, hematological), time of diagnosis (>5 years ago), or stage (in situ/localized) did not have inferior survival compared with patients with no prior cancer. We tested one form of prior cancer exclusion criteria in an NPC cohort resembling a modern trial population: it did not adversely affect overall and NPC-specific survival. Conclusions Many NPC trials excluded patients with prior cancer, which impacts trial accrual and generalizability. Our findings suggest that broader inclusion in trials of patients with NPC with prior cancer might not affect trial outcomes. More research is needed to understand the appropriateness of this exclusion policy across cancer types and trials.

Induction chemotherapy followed by concurrent chemoradiotherapy is the standard of care for patients with locoregionally advanced nasopharyngeal carcinoma (NPC). However, survival benefits from additional induction chemotherapy varied significantly among patients. This study aimed to determine the predictive value of body mass index (BMI) in induction chemotherapy in NPC.This post-hoc analysis included patients from two multicenter, randomized, phase 3 trials (NCT01245959 and NCT01872962), in which patients were randomized to receive induction chemotherapy plus concurrent chemoradiotherapy or concurrent chemoradiotherapy alone.Among 960 patients participated, 957 were included in this analysis. 82 (8.6%) patients had baseline BMI 18.5 kg/mUsing pooled data from two landmark phase III trials, we found that underweight patients might not benefit from additional induction chemotherapy in locoregionally advanced NPC. If confirmed in prospective studies, this could help guide individual treatment in the clinic.

Objectives To screen subgroup potentially benefiting from cumulative cisplatin dose (CCD) ≥ 200 mg/m2 during concurrent chemoradiotherapy (CCRT) of patients with locoregionally-advanced nasopharyngeal carcinoma (LA-NPC) receiving induction chemotherapy (IC) and CCRT. Materials and Methods In total, 2 063 patients with non-disseminated LA-NPC diagnosed from 2009 to 2015 receiving IC plus CCRT were enrolled. Patients were restaged based on proposed stage groupings and risk groupings was established. After propensity score matching, survival outcomes were compared within different risk groupings with 200 mg/m2 CCD. Post-IC gross primary tumor (GTVp) and lymph node (GTVnd) volumes were calculated from planning computed tomography. The role of risk groupings and post-IC tumor volume to CCD was explored. Results Compared with the low-risk group, the high-risk group showed poor survival outcomes in terms of 5-year progression-free survival (PFS), overall survival (OS), distant metastasis-free survival (DMFS), and locoregional relapse-free survival (LRRFS). CCD ≥ 200 mg/m2 improved survival in terms of 5-year PFS, OS and DMFS in the high-risk group but not in the low-risk group. High-risk patients with unfavorable response to IC benefited from CCD ≥ 200 mg/m2 with respect to PFS and DMFS; while those in low-risk group or with favorable response to IC didn’t. Conclusions Risk groupings was effective for risk stratification. Combining risk groupings and post-IC tumor volume is a simple and useful method to guide individualized CCD treatment of CCRT for patients with LA-NPC receiving IC and CCRT. CCD ≥ 200 mg/m2 may be indicated for high-risk patients with unfavorable response to IC.

Objectives To investigate the role of sequential chemoradiotherapy (SCRT; induction chemotherapy [IC] followed by intensity-modulated radiotherapy [IMRT]) in stage II and low-risk stage III–IV nasopharyngeal carcinoma (NPC). Materials and methods Four well-matched groups were individually generated using propensity score matching in patients (n = 689) with stage II (SCRT vs. concurrent chemoradiotherapy [CCRT], SCRT vs. IMRT alone) and low-risk stage III–IV NPC (SCRT vs. CCRT, SCRT vs. IC + CCRT). Five-year overall/disease-free/locoregional relapse-free/distant metastasis-free survival (OS/DFS/LRRFS/DMFS) and acute hematological toxicities were compared between groups. The value of SCRT was further investigated in multivariate analysis and subgroup analysis by adjusting for covariates and limiting IC-to-IMRT time interval, respectively. Results SCRT led to equivalent survival outcomes compared to CCRT/IMRT alone and CCRT/IC + CCRT in stage II and low-risk stage III–IV NPC, respectively (all P > .050). In multivariate analysis, patients with stage II NPC treated by SCRT obtained higher DMFS (AHR = 0.22, 95% CI = 0.05–1.00, P = .050), but not OS, DFS or LRRFS, compared to patients receiving CCRT; non-significant differences were observed between SCRT and other treatments. SCRT with short IC-to-IMRT time interval (≤70 days) achieved higher 5-year survival rates than IMRT alone (DMFS: P = .046), CCRT (stage II NPC; OS: P = .047; DMFS: P = .020) and IC + CCRT (DFS: P = .041). Moreover, SCRT was associated with higher, equivalent and lower frequencies of acute hematological toxicities than IMRT alone, CCRT and IC + CCRT, respectively. Conclusion SCRT is mainly beneficial in stage II NPC, leading to better DMFS and/or equivalent acute hematological toxicities compared to CCRT/IMRT alone. CCRT is still the best choice for low-risk stage III–IV NPC.

Twelve weeks after radiotherapy is the recommended time-point for assessing tumor response in nasopharyngeal carcinoma (NPC); however, regression after 12 weeks remains unclear. We explored NPC regression and the prognosis of patients with delayed clinical complete response (cCR).MRI images of 556 NPC patients treated with intensity-modulated radiotherapy (IMRT) between 2009 and 2012 were retrospectively reviewed. Clinical tumor response was assessed at 3-4 (assessment 1) and 6-9 months (assessment 2) after IMRT, and survival rates were compared.Of the 556 patients, 463 (83.3%) had cCR at assessment 1 (early cCR). Of the 93 patients with partial response at assessment 1, 45 (48.4%) achieved cCR at assessment 2 (delayed cCR), and 48 did not have cCR at assessment 2 (non-cCR). Locoregional failure rate was lower in patients with a cCR than those without a cCR at assessment 1 (7.1% vs. 26.9%, P .001) and assessment 2 (7.1% vs. 45.8%, P .001). Multivariate analysis showed cCR was a favorable prognostic factor for locoregional failure-free survival (LRFFS), failure-free survival (FFS), and overall survival (OS). Early and delayed cCR groups had better 5-year LRFFS (92.6% vs. 93.3% vs. 54.2%), FFS (83.8% vs. 84.4% vs. 48.5%) and OS (92.1% vs. 90.6% vs. 65.4%) than the non-cCR group (all P .001).Nearly half of the patients with partial response at 3-4 months achieve cCR by 6-9 months; delayed cCR is not a poor prognosticator. We suggest later assessment of cCR at 6-9 months after IMRT is acceptable in responding NPC.

Objectives To clarify the incidence of brainstem toxicity and perform a dose-volume analysis for the brainstem after long-term follow-up of a large cohort of nasopharyngeal carcinoma (NPC) patients who underwent intensity-modulated radiation therapy (IMRT). Materials and methods All patients with NPC treated with IMRT at Sun Yat-sen University Cancer Center between April 2009 and March 2012 were retrospectively reviewed. A total of 1544 patients with follow-up >12 months and detailed treatment plan data were included. Radiotherapy was administered using the simultaneous integrated boost technique in 2.0–2.48 Gy per fractions/28–33 fractions. Brainstem necrosis was defined as lesions with high signal intensity on T2-weighted images and low signal intensity on T1-weighted images, with or without enhancement after administration of contrast in follow-up MRI. Results After median follow-up of 79.7 months (range, 12.2–85.6 months), 2/1544 (0.13%) patients developed brainstem necrosis after intervals of 12.3 and 18.5 months. Actuarial incidence of brainstem necrosis was 0.07%, 0.13%, 0.13% and 0.13% after 1, 2, 3 and 5 years, respectively. Overall, 384 (24.9%), 153 (9.9%), 67 (4.3%), 39 (2.5%), 78 (5.1%), and 114 (7.4%) patients had excessive doses of D max ≥ 64 Gy, D1 cc > 59 Gy, D2 cc > 59 Gy, aV50 > 5.9 cc, aV55 > 2.7 cc and aV60 > 0.9 cc respectively, of whom only two developed brainstem necrosis. Conclusions Brainstem necrosis is rare in NPC. The definitive criteria based on conventional radiotherapy cannot accurately predict the occurrence of brainstem necrosis after IMRT, thus more flexible definitive criteria with strict restrictions need to be defined.

Objectives To investigate the feasibility of contralateral lower neck sparing intensity modulation radiated therapy (IMRT) for nasopharyngeal carcinoma patients (NPC) with unilateral cervical lymph node metastasis. Materials and methods Retrospective review of 546 patients with unilateral cervical lymph node metastasis treated between November 2009 and February 2012 at one institution. All patients were staged using magnetic resonance imaging and received radical IMRT. Patients were classified into two groups: the inferior border of the negative neck irradiation field only covered Levels III to Va in Group 1; the inferior border covered entire neck down to Levels IV to Vb in Group 2. Results Median follow-up was 49.9 months (range, 1.3–69.2 months). Four-year overall survival (OS:89.3% vs. 88.9%, P = 0.91), disease-free survival (DFS:81.7% vs. 81.0%, P = 0.91), distant metastasis-free survival (DMFS:88.2% vs. 87.9%, P = 0.95), local relapse-free survival (LRFS:96.7% vs. 94.7%, P = 0.70) and nodal relapse-free survival (NRFS: 96.1% vs. 95.9%, P = 0.94) were not significantly different between Group 1 and Group 2. Twenty-two patients developed cervical lymph node relapse; of whom 20/22 (91.0%) developed unilateral relapse within pretreatment positive neck. Only one patient developed out-of-field relapse, though this patient also relapsed within the neck irradiation field (Level II). No clinicopathological feature tested had significant prognostic value for NRFS in multivariate analysis. Conclusions In the IMRT and MRI era, contralateral lower neck sparing IMRT seems to be feasible for NPC patients with unilateral cervical lymph node metastasis.

The subgroups of patients with nasopharyngeal carcinoma (NPC) who benefit from induction chemotherapy plus concurrent chemoradiotherapy (IC+CCRT) remain unclear.We established prognostic nomograms for overall survival (OS) and disease-free survival (DFS), and validated the nomograms in 1230 patients with NPC and subgroup of 923 patients with locoregionally advanced NPC (LANPC). Three well-matched risk groups (i.e., low, intermediate and high risk) were created via recursive partitioning and 1-to-1 propensity score matching; IC+CCRT was compared with CCRT in each risk group.Histological type, T category, N category, plasma Epstein-Barr virus deoxyribonucleic acid (and the same factors plus age and neutrophil-lymphocyte ratio) were included in the nomograms for DFS (and OS). Both nomograms had higher c-indexes than the 7th edition staging system in both NPC/LANPC (all P-values≤0.010). The nomogram for OS also had a higher c-index in LANPC than the 8th edition staging system (P-value=0.052). OS was significantly different between all three risk groups in the individualized risk stratification (all P-values0.001), while the 7th and 8th edition staging systems failed to clearly separate OS for stage II and III disease (P-value=0.415 and 0.347, respectively). IC+CCRT improved OS in intermediate and high risk patients with LANPC compared to CCRT alone (P-value0.001 and P-value=0.002, respectively).These prognostic nomograms could accurately guide treatment of individual patients with NPC. IC+CCRT could improve OS for patients with LANPC at intermediate to high risk.

Objectives The aim of this study is to optimize the cycle for patients with locoregionally advanced nasopharyngeal carcinoma (NPC) receiving neoadjuvant chemotherapy (NCT) in the era of intensity-modulated radiotherapy (IMRT). Materials and methods Data on 569 locoregionally advanced NPC patients treated with IMRT were retrospectively reviewed. Propensity score matching (PSM) method was adopted to balance prognostic factors and match patients. Survival outcomes of matched patients between different NCT cycle groups were compared. Results The median cycle of NCT was 2 (range, 2–4 cycles) for the whole cohort, and patients were therefore stratified as low cycle (=2) and high cycle (>2) groups. In total, 247 pairs of NPC patients were selected by PSM. Univariate analysis found no significantly prognostic difference between the low cycle and high cycle groups, and multivariate analysis did not establish NCT cycle as an independent factor. However, stratified analysis revealed patients in the low cycle group had better OS than those of patients in the high cycle group (92.4% vs. 80.8%, P = 0.029), and NCT was identified as an independent prognostic factor for OS in patients with N2-3 category (HR, 2.252; 95% CI, 1.024–4.953; P = 0.043). Conclusion Two cycles of NCT may be enough and additional more cycles are not associated with improved survival outcomes for patients with locoregionally advanced NPC in the era of IMRT.

Objectives To explore the role of induction chemotherapy (IC) followed by concurrent chemoradiotherapy (CCRT) and CCRT plus adjuvant chemotherapy (AC) in locoregionally advanced nasopharyngeal carcinoma (LANPC). Materials and methods The propensity score-matched (PSM) method was adopted to balance variables. We identified independent prognostic factors using Cox regression analysis and compared outcomes between two chemotherapy treatment combinations for patients in different subgroups. Results A total of 550 patients were selected by one-to-two PSM. Survival outcomes for the matched data set indicated that the IC + CCRT group achieved higher 5-year overall survival (OS; 89.3% vs 85.3%, P = 0.119), failure-free survival (FFS; 80.2% vs 79.0%, P = 0.722) and distant metastasis-free survival (DMFS; 87.4% vs 84.4%, P = 0.322) compared with CCRT + AC, although this was statistically non-significant. Subgroup analysis revealed that IC + CCRT was associated with significantly improved OS (Hazard ratio [HR] = 2.68, 95% Confidence interval [CI] = 1.16–6.22, P = 0.017), FFS (HR = 1.94, 95% CI = 1.06–3.57, P = 0.029) and locoregional relapse-free survival (LRRFS; HR = 2.63, 95% CI = 1.04–6.68, P = 0.034) in T3 disease. Moreover, this combination of treatment could significantly prolong OS (HR = 3.72, 95% CI = 1.41–9.80, P = 0.004) in N2 disease. However, the superiority of CCRT + AC was only observed in LRRFS (HR = 0.18, 95% CI 0.04–0.79, P = 0.010) for the T4 subgroup. Conclusion IC + CCRT should be strongly considered by patients with LANPC, especially those with T3 or N2 disease.

Objectives Definitive concurrent chemoradiotherapy (CCRT) is the standard treatment for locoregionally advanced nasopharyngeal carcinoma (NPC). The cumulative cisplatin dose (CCD) during radiotherapy is an important prognostic factor; however, the optimal CCD is undetermined. Materials and methods In this retrospective analysis, patients with locoregionally advanced NPC treated with single-agent cisplatin-based CCRT or RT alone from 2009 through 2015 were identified. CCD was entered into a multivariate Cox regression model as a continuous variable using natural cubic splines to allow for a nonlinear relationship between CCD and outcomes. The primary endpoint was overall survival, and the secondary endpoints were locoregional relapse‐free survival and distant metastasis‐free survival. Results A total of 2 924 patients were included in our study, with a median CCD of 160 mg/m2 (range, 0–300 mg/m2). As the CCD increased, the risk of death remained steady until 180 mg/m2, then decreased sharply until 250 mg/m2, and then increased until 300 mg/m2. The optimal CCD of 230–270 mg/m2 was associated with the lowest risk of death and disease relapse. However, the CCD had less prognostic value for disease control, especially for distant control among high-risk patients (N2–3 or T4). Conclusions A CCD dose of 230–270 mg/m2 (240 mg/m2 is recommended) is optimal for patients with locoregionally advanced NPC, especially for those at low risk (T1–3 and N0–1). For high-risk patients (N2–3 or T4), additional chemotherapy should be administered before or after CCRT.

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.

Objectives This study aimed at identifying the optimal induction chemotherapy regimen for patients with locoregionally advanced nasopharyngeal carcinoma (NPC) treated by intensity-modulated radiotherapy. Materials and methods We identified eligible patients with newly-diagnosed stage III-IVA NPC (excluding T3N0) between September 2009 and May 2015. Survival outcomes and grade 3–4 toxicities were compared between different IC regimen groups. Results In total, 3738 patients were eligible for this study, with 1572 (42.1%), 1085 (29.0%) and 1081 (28.9%) receiving TPF, PF and TP, respectively. In the whole population, multivariate analysis found that TPF seems to be better than PF and TP. Howerver, subgroup analysis revealed TPF and TP had same effectiveness in patients receiving a cumulative cisplatin dose (CCD) ≥ 200 mg/m2 in concurrent chemotherapy, while TPF shows relatively better survival benefit in patients receiving CCD Conclusions Our study concluded that induction TP regimen may be enough for patients receiving a CCD ≥ 200 mg/m2, while TPF may be superior to TP and PF for patients receiving a CCD