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

Recurrent Versus Metastatic Head and Neck Cancer: An Evolving Landscape and the Role of Immunotherapy

Squamous cell carcinoma of the head and neck (SCCHN) is among the ten most common cancers worldwide, with advanced SCCHN presenting with a 5-year survival of 34% in the case of nodal involvement and 8% in the case of metastatic disease. Disease-free survival at 2 years is 67% for stage II and 33% for stage III tumors, whereas 12-30% of patients undergo distant failures after curative treatment. Previous treatments often hinder the success of salvage surgery and/or reirradiation, while the standard of care for the majority of metastatic SCCHN remains palliative chemo- and immuno-therapy, with few patients eligible for locoregional treatments. The aim of this paper is to review the characteristics of recurrent SCCHN, based on different recurrence sites, and metastatic disease; we will also explore the possibilities not only of salvage surgery and reirradiation but also systemic therapy choices and locoregional treatment for metastatic SCCHN.

PD-1 Inhibitors Combined with Chemotherapy versus Re-irradiation/chemoradiotherapy for Unresectable Locally Recurrent T3-4 Nasopharyngeal Carcinoma: A Retrospective Study

Objective: To evaluate the efficacy, toxicity, and long-term outcomes of PD1 inhibitors plus chemotherapy versus re-irradiation/chemoradiotherapy in patients with unresectable locally recurrent T3-4 nasopharyngeal carcinoma (NPC). Methods: A retrospective analysis was conducted on 42 patients with recurrent nasopharyngeal cancer (NPC) after receiving immunochemotherapy or re-irradiation between February 2018 and May 2022 in Zhejiang Cancer Hospital. Overall survival (OS), progression-free survival (PFS), local recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) were determined using the Kaplan-Meier method, log-rank test, and Cox proportional hazard regression. Results: With a median follow-up duration of 28.7 months (ranging from 7.2 to 63.9 months), the 3-year OS rate was 23.3% in the re-irradiotherapy (RI) group (N = 24) and 59.6% in the immunochemotherapy (IC) group (N = 18) (p = 0.042). The 3-year PFS, LRFS, and DMFS rates were not significantly different between the two groups (PFS: 45.3% vs. 62.6%, P = 0.482; LRFS: 54.4% vs. 62.6%, P =0.891; DMFS: 89.8% vs. 100.0%, P = 0.489). The univariate analysis revealed that regimen (HR: 0.354, 95% CI: 0.130-0.962, P = 0.042) was significantly correlated with OS. Multivariate analysis also showed that treatment regimen (HR: 0.329, 95% CI: 0.12-0.970, P =0.044) was the only significant prognostic factor associated with OS. The most common late toxicities in the RI group were xerostomia, deafness, and nasopharyngeal necrosis. Of these, nasopharyngeal necrosis was present in 16 patients (66.7%) and in 10 patients (41.7%) at a grade 3 or above. Nasopharyngeal necrosis is the main cause of death in the RI group. In contrast, in the IC group, grade 3 or higher immune-related adverse events or late adverse events were not observed. Conclusions: For unresectable locally recurrent NPC, re-irradiation is an effective treatment; nevertheless, the survival obtains are usually surpassed by serious late complications. For these individuals, chemotherapy in addition to an anti-PD-1 checkpoint inhibitor may be a helpful course of treatment.

Salvage endoscopic nasopharyngectomy for recurrent nasopharyngeal carcinoma in a non-endemic area

PURPOSE

To analyze oncological outcomes of endoscopic surgical treatment of locally recurrent EBV-related undifferentiated non-keratinizing nasopharyngeal carcinoma (uNK-NPC) in a non-endemic area.

METHODS

Retrospective review of patients affected by recurrent uNK-NPC treated with nasopharyngeal endoscopic resection (NER) in a tertiary-care referral center from 2003 to 2022, by evaluating survival rates, prognostic factors, and follow-up strategies.

RESULTS

The oncological outcomes of 41 patients were analyzed, over a mean follow-up period of 57 months. The 5-year overall, disease-specific, and disease-free survival of the cohort were 60.7% ± 8.9%, 69% ± 9%, and 39.7% ± 9.2%, respectively. The local (rT) and regional (rN) extension of recurrent disease, stage of disease, and status of resection margins appeared to significantly influence survivals. After a mean follow-up period of 21 months, a further recurrence after NER was observed in 36.6% of cases. Skull base osteonecrosis induced by previous irradiation and post-surgical bone remodeling represent the major challenges for early detection of further local relapses during postoperative follow-up.

CONCLUSION

NER appeared as a safe and effective treatment for recurrent uNK-NPC. The adequate selection of patients eligible for NER is essential, to maximize the chances to cure and minimize the risk of local complications.

Is a total dose of 54 Gy with radiochemotherapy sufficient for treatment of intermediate-risk volumes in nasopharyngeal cancer?

BACKGROUND

The mainstay treatment of nasopharyngeal cancer (NPC) is radiation therapy (RT). The doses and volumes may differ from center to center. Most studies and guidelines recommend a total dose of 60 Gy for elective nodal and peritumoral volume treatment. This retrospective analysis aimed to analyze whether a dose reduction to 54 Gy to this volume would be associated with a higher risk of recurrence.

METHODS

A total of 111 patients treated by intensity-modulated radiotherapy (IMRT) and concurrent chemotherapy were retrospectively analyzed. The recurrent tumor volume was classified as "in field" if 95% of the recurrent volume was inside the 95% isodose, as "marginal" if 20-95% of the recurrence was inside the 95% isodose, or as "outside" if less than 20% of the recurrence was inside the 95% isodose.

RESULTS

Median follow-up was 67 months (range 6-142). The 2‑ and 5‑year overall survival (OS) rates were 88.6% and 70%, respectively. The 2‑year locoregional control (LRC), disease-free survival (DFS), and distant metastasis-free survival (DMFS) were 93.3%, 89.3%, and 87.4%, and the 5‑year LRC, DFS, and DMFS were 86.8%, 74%, and 81.1%, respectively. Ten patients (9%) had a local and or regional recurrence. Half of the patients with locoregional failure had in-field recurrences. For primary tumor, there was no recurrence in the volume of 54 Gy. For regional lymph node volume, recurrence was detected in two (1.8%) patients in the volume of 54 Gy.

CONCLUSION

These retrospective data suggest that a dose reduction may be possible for intermediate-risk volumes, especially for the primary site.

ADAM22 acts as a novel predictive biomarker for unfavorable prognosis and facilitates metastasis via PI3K/AKT signaling pathway in nasopharyngeal carcinoma

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a type of epithelial malignancy known for its high likelihood of metastasizing to distant organs, which remains the primary obstacle in the treatment of NPC. The present study aimed to identify potential intervention target for NPC metastasis.

METHODS

The differentially expressed genes (DEGs) were firstly analyzed and intersected across various NPC related datasets in the Gene Expression Omnibus database. Subsequently, various techniques including quantitative polymerase chain reaction (qPCR), western blotting, immunohistochemistry, migration and invasion assays, in conjunction with bioinformatics and prognostic modeling, were utilized to elucidate the role of candidate genes in NPC metastasis.

RESULTS

We discerned the gene a disintegrin and metalloprotease 22 (ADAM22) as a distinct and significant factor in the progression and metastasis of NPC through five datasets. The elevated expression of ADAM22 was observed in clinical tissue and plasma samples with advanced NPC, as well as in high metastatic cells. Furthermore, we highlighted its essential role in a prognostic model that demonstrated strong prediction performance for NPC. Notably, overexpression of ADAM22 was found to enhance the aggressiveness and epithelial-mesenchymal transition (EMT) of low metastatic NPC cells, whereas the downregulation of ADAM22 resulted in suppressed effect in high metastatic cells. Delving into the mechanism, ADAM22 activated the PI3K/Akt signaling pathway through the mediation of Rac Family Small GTPase 2 (RAC2), thereby facilitating EMT and metastasis in NPC.

CONCLUSIONS

The study provided pioneering insights that ADAM22 had the potential to act as an oncogene by promoting EMT and metastasis of NPC through the RAC2-mediated PI3K/Akt signaling pathway. Thus, ADAM22 could serve as a novel prognostic indicator in NPC.

Patterns and Prognosis of Local Recurrence of Nasopharyngeal Carcinoma after Intensity-modulated Radiotherapy

Objective: To investigate the patterns of local failure and prognosis in patients with locally recurrent nasopharyngeal carcinoma (rNPC) after primary intensity-modulated radiotherapy (IMRT). Methods: The data of 298 patients with locally rNPC after IMRT were retrospectively analyzed. Magnetic resonance images of the initial and recurrent tumors were reviewed and, for patients with extra-nasopharyngeal local recurrence, the gross tumor volume of local recurrence was transferred to the original IMRT plan for dosimetry analysis. Significant prognostic factors for overall survival (OS) were selected by multivariate Cox regression analysis. Results: The commonest recurrence sites were the nasopharynx (93%, 277/298) and skull base (53.7%, 160/298). Of the 21 patients with extra-nasopharyngeal recurrence (19 cases valid), 12 had in-field failures, 4 had marginal failures, and 3 had out-field failures. The ethmoid sinus (57.1%, 4/7) and nasal cavity (28.6%, 2/7) were the most frequent sites of marginal and out-field failures. After median follow-up of 37 months, the 3-year and estimated 5-year OS rates were 57.3% and 41.7%, respectively. Multivariate analysis showed that age, recurrence interval, plasma Epstein-Barr virus (EBV) DNA level, and recurrent T stage were independent prognostic factors for OS. Conclusions: Local failure after IMRT occurs most commonly in the nasopharynx and skull base. In patients with extra-nasopharyngeal recurrence, in-field failure remains the main failure pattern, and marginal and out-field failures mainly occur in the ethmoid sinus and nasal cavity. Elder age, shorter recurrence interval, detectable plasma EBV DNA, and advanced recurrent T stage are negative predictors of OS in patients with rNPC.

18F-FMISO PET-guided dose escalation with multifield optimization intensity-modulated proton therapy in nasopharyngeal carcinoma

PURPOSE

The purpose of this study was to evaluate the radiotherapy planning feasibility of dose escalation with intensity-modulated proton therapy (IMPT) to hypoxic tumor regions identified on 18F-Fluoromisonidazole (FMISO) positron emission tomography and computed tomography (PET-CT) in NPC.

MATERIALS AND METHODS

Nine patients with stages T3-4N0-3M0 NPC underwent 18F-FMISO PET-CT before and during week 3 of radiotherapy. The hypoxic volume (GTVhypo) is automatically generated by applying a subthresholding algorithm within the gross tumor volume (GTV) with a tumor to muscle standardized uptake value (SUV) ratio of 1.3 on the 18F-FMISO PET-CT scan. Two proton plans were generated for each patient, a standard plan to 70 Gy and dose escalation plan with upfront boost followed by standard 70GyE plan. The stereotactic boost was planned with single-field uniform dose optimization using two fields to deliver 10 GyE in two fractions to GTVhypo. The standard plan was generated with IMPT with robust optimization to deliver 70GyE, 60GyE in 33 fractions using simultaneous integrated boost technique. A plan sum was generated for assessment.

RESULTS

Eight of nine patients showed tumor hypoxia on the baseline 18F-FMISO PET-CT scan. The mean hypoxic tumor volume was 3.9 cm³ (range .9-11.9cm³ ). The average SUVmax of the hypoxic volume was 2.2 (range 1.44-2.98). All the dose-volume parameters met the planning objectives for target coverage. Dose escalation was not feasible in three of eight patients as the D0.03cc of temporal lobe was greater than 75GyE.

CONCLUSIONS

The utility of boost to the hypoxic volume before standard course of radiotherapy with IMPT is dosimetrically feasible in selected patients. Clinical trials are warranted to determine the clinical outcomes of this approach.

Unraveling the patterns and pathways of local recurrence of nasopharyngeal carcinoma: evidence for individualized clinical target volume delineation

BACKGROUNDS

Despite publication of international guidelines, there are notable controversial points of clinical target volume (CTV) delineation in nasopharyngeal carcinoma (NPC). Recently, scholars proposed a novel way of delineation of CTV in NPC-individualization of CTV delineation based on T classification and spread patterns, which yielded excellent long-term local control with limited late toxicities. The aim of this study was to clarify the anatomic patterns and pathways of local recurrence of NPC and provide a clinical reference for the delineation of CTV.

METHODS

A total of 869 patients with non-metastatic NPC were treated with intensity-modulated radiation therapy (IMRT) at our institution between 2009 and 2010. Among the 57 cases of local/locoregional recurrence, 52 cases with traceable radiotherapy plans and magnetic resonance imaging at the time of the first diagnosis of recurrence were included. Anatomical structures and gross tumor volume of local recurrence were contoured. The incidence of relapse of each anatomic structure, route of local recurrence, and their correlation were analyzed.

RESULTS

Locally advanced disease had a significantly increased risk of recurrence in the posterior nasal cavity and a trend towards higher risk of recurrence in the clivus, lateral pterygoid muscle, and hypoglossal canal. Based on the incidence of local recurrence, we constructed a high-risk map for the early and locally advanced stages. Local recurrences were classified into five routes, where anterior extension accounted for the majority (30.8%), and caudal tumor extension pathway had the lowest incidence (5.8%). There was a significant correlation between the local recurrences of neural foramina and neighboring anatomical structures along each pathway. All cases relapsed at unilateral cavernous sinus, most at the same side of primary tumor. Based on our findings, we proposed some suggestions on delineations of CTV, based on T classification and local extension pattern.

CONCLUSIONS

Local recurrence of NPC varied according to T classification, followed a stepwise pattern, spread via neural foramina, and recurred at ipsilateral cavernous sinus. This provides meaningful clinical evidence for delineation of CTV, especially individualized delineation.

Reconstruction of nasopharyngeal defect with submental flap during surgery for nasopharyngeal malignant tumors

Objective

To investigate the feasibility and effect of a pedicled submental flap in postoperative defect repair of nasopharyngeal malignant tumors.

Methods

Eight cases (six women, two men; age, 29–63 years) of postoperative defects after resection of malignant nasopharyngeal tumors with a lesion stage of (r) T_1–3N_0–2M₀ were retrospectively analyzed. Preoperative enhanced thin-slice computed tomography of the neck was performed to predict the submental flap reflux vein. The submental flap was prefabricated during the operation, and the nasopharyngeal mass was removed through the parapharyngeal space approach combined with nasal endoscopy/mandibular external rotation/maxillary overturning. The submental flap was elevated to the nasopharyngeal defect area through the parapharyngeal space for repair.

Results

Intraoperative examination confirmed that among the eight submental flaps, three had venous drainage into the internal jugular vein and five had venous drainage into the external jugular vein; these findings were consistent with the preoperative computed tomography findings. The size of the submental flap was 8–10 cm × 5–6 cm. The repair range reached the eustachian orifice on the healthy side and extended to the posterior wall of the maxillary sinus on the affected side. The flap extended to the posterior upper part of the nasal septum at the top, to the oropharynx at the bottom, and to the bony surface of the skull base at the deep side. Primary healing after surgery was achieved, and no flap necrosis occurred. After 3–77 months of follow-up, one patient with recurrent nasopharyngeal carcinoma after radiotherapy developed cervical lymph node recurrence again, one patient with adenoid cystic carcinoma had lung metastasis, and the remaining six patients had no recurrence.

Conclusions

The pedicled submental flap is used to repair postoperative defects in the nasopharyngeal region through the cervical parapharyngeal space. It is a simple and fast procedure with adequate tissue volumes. The flap can effectively protect important structures such as the internal carotid artery and reduce the risk of infection and bleeding from postoperative wound exposure.

Long-term results of the phase II dose and volume de-escalation trial for locoregionally advanced nasopharyngeal carcinoma

OBJECTIVE

Patients with locoregionally advanced nasopharyngeal carcinoma (LANPC) were assigned to dose and volume de-escalated intensity-modulated radiation therapy (IMRT) based on response to induction chemotherapy (IC) to limit treatment related toxicity while preserving efficacy.

METHODS AND MATERIALS

A single-arm de-escalated phase II trial was performed in this study. Patients with LANPC received two cycles of IC with docetaxel 60 mg/m² d1, cisplatin 25 mg/m²/day d1-3 and 5-fluorouracil 500 mg/m²/day d1-5 q21d, followed by IMRT. The gross tumor volume of the primary intracavity nasopharyngeal tumor and involved lymph nodes were delineated based on the post-IC tumor extension. Part of the prescribed doses were reduced from 70.4 Gy to 66 Gy for T3-4 diseases. The primary end point was 5-year progression-free survival (PFS) in stage III and IVA-B NPC compared with historical controls of 50% and 35%.

RESULTS

Between January 2010 and November 2013, 48 and 83 eligible patients with stage III and IVA-B NPC were accrued to this trial. With a median follow-up of 92 months, the 5-year and 8-year estimated PFS were 89.6% and 76.0%, 63.9% and 58.0% for patients with stage III and IVA-B disease, which were all improved in comparison with historical controls. Grade 3 acute mucositis were developed in 27.5% patients. Cranial neuropathy and asymptomatic temporal lobe necrosis were found in 2.3% and 1.5% patients.

CONCLUSION

Dose and volume de-escalated IMRT was associated with high PFS and mild late neurological toxicities for IC responders. Further exploration of de-escalation strategies in appropriate patients is needed.

CLINICAL TRIAL REGISTRATION

Clinical trials.gov identifier: NCT03389295.

Clinical Characteristics and Predictive Outcomes of Recurrent Nasopharyngeal Carcinoma-A Lingering Pitfall of the Long Latency

Purpose: To investigate the clinical characteristics, risk factors, and clinical outcomes of long-latent recurrence (>five years) of nasopharyngeal carcinoma (NPC). Methods: This retrospective study enrolled newly diagnosed NPC patients from the Chang Gung Research Database between January 2007 and December 2019. We analyzed the patients’ characteristics and survival outcomes after recurrence. Results: A total of 2599 NPC patients were enrolled. The overall recurrence rate was 20.5%, while 8.1% of patients had long-latent recurrence (>five years). These patients had a higher percentage of initial AJCC (The American Joint Committee on Cancer) stage I/II (60.5%, p = 0.001) and local recurrence (46.5%, p < 0.001). Unresectable rT3 and rT4 were found in 60% of patients when recurrence and 30% of local recurrence occurred in the skull base, which could not be detected by the regular endoscopy. The five-year overall survival rate of long-latent recurrence was 19.7%. Alive patients tended to be asymptomatic but have regular follow-ups with the interval less than six months. Multivariate analysis showed age and initial advanced AJCC stages were independent risk factors of death after recurrence. In contrast, patients with recurrence between two and five years, salvage surgeries, and regional recurrence had favorable survival outcomes. Conclusion: Long-latent NPC recurrence is not rare, and the survival outcome is poor. Regular follow-up for early detection of NPC recurrence is necessary even after five years of disease-free period.

Failure Patterns of Recurrence and Metastasis After Intensity-Modulated Radiotherapy in Patients With Nasopharyngeal Carcinoma: Results of a Multicentric Clinical Study

Purpose

This study aimed to explore factors associated with recurrence and metastasis after intensity-modulated radiotherapy (IMRT) in patients with nasopharyngeal carcinoma (NPC) and provide evidence for NPC treatment.

Methods

We retrospectively analysed the treatment dose and survival outcomes of 645 patients with nasopharyngeal carcinoma without distant metastases treated with IMRT for the first time at three treatment centres in the Guangxi Zhuang Autonomous Region, China, between January 2009 and December 2012.

Results

There were 9.3% of patients (60/645) had recurrence and 17.5% (113/645) had distant metastasis 5 years after treatment. The 1-year, 3-year and 5-year local recurrence rates were 0.9%, 6.5% and 9.0% respectively. And the 1-year, 3-year and 5-year distant metastasis rates were 3.4%, 10% and 17.2%, respectively. In the 60 patients with recurrence, the in-field, marginal-field, and out-field recurrence rates were 93.3% (56/60), 5.0% (3/60) and 1.7% (1/60), respectively. Recurrence failures occurring within the first three years after treatment accounted for 81.7% (49/60). In the 113 patients with metastasis, the size of the cervical lymph node, the presence of lower cervical lymph node metastasis, the residual cervical lymph node size and the time of residual cervical lymph node complete response (CR) were independent prognostic factors for DMFS (P <0.05).

Conclusion

Most recurrences occured in the first three years after IMRT. In-field recurrence was the most common pattern for loco-regional failure of NPC treatment. The risk of distant metastasis was positively correlated with higher N stage, lower neck nodal metastasis, larger size of cervical lymph nodes, and longer time to response for residual NPC in cervical adenopathy.

The Chinese Society of Clinical Oncology (CSCO) clinical guidelines for the diagnosis and treatment of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a malignant epithelial tumor originating in the nasopharynx and has a high incidence in Southeast Asia and North Africa. To develop these comprehensive guidelines for the diagnosis and management of NPC, the Chinese Society of Clinical Oncology (CSCO) arranged a multi‐disciplinary team comprising of experts from all sub‐specialties of NPC to write, discuss, and revise the guidelines. Based on the findings of evidence‐based medicine in China and abroad, domestic experts have iteratively developed these guidelines to provide proper management of NPC. Overall, the guidelines describe the screening, clinical and pathological diagnosis, staging and risk assessment, therapies, and follow‐up of NPC, which aim to improve the management of NPC.

A novel dosimetric metrics-based risk model to predict local recurrence in nasopharyngeal carcinoma patients treated with intensity-modulated radiation therapy

Background

To develop a risk model based on dosimetric metrics to predict local recurrence in nasopharyngeal carcinoma (NPC) patients treated with intensive modulated radiation therapy (IMRT).

Methods

493 consecutive patients were included, among whom 44 were with local recurrence. One-to-two propensity score matching (PSM) was used to balance variables between recurrent and non-recurrent groups. Dosimetric metrics were extracted, and critical dosimetric predictors of local recurrence were identified by Cox regression model. Moreover, recurrent sites and patterns were examined by transferring the recurrent tumor to the pretreatment planning computed tomography.

Results

After PSM, 44 recurrent and 88 non-recurrent patients were used for dosimetric analysis. The univariate analysis showed that eight dosimetric metrics and homogeneity index were significantly associated with local recurrence. The risk model integrating D₅ and D₉₅ achieved a C-index of 0.706 for predicting 3-year local recurrence free survival (LRFS). By grouping patients using median value of risk score, patients with risk score ˃ 0.885 had significantly lower 3-year LRFS (66.2% vs. 86.4%, p = 0.023). As for recurrent features, the proportion of relapse in nasopharynx cavity, clivus, and pterygopalatine fossa was 61.4%, 52.3%, and 40.9%, respectively; and in field, marginal, and outside field recurrence constituted 68.2%, 20.5% and 11.3% of total recurrence, respectively.

Conclusions

The current study developed a novel risk model that could effectively predict the LRFS in NPC patients. Additionally, nasopharynx cavity, clivus, and pterygopalatine fossa were common recurrent sites and in field recurrence remained the major failure pattern of NPC in the IMRT era.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-021-01911-5.

Convolutional neural network in nasopharyngeal carcinoma: how good is automatic delineation for primary tumor on a non-contrast-enhanced fat-suppressed T2-weighted MRI?

PURPOSE

Convolutional neural networks (CNNs) show potential for delineating cancers on contrast-enhanced MRI (ce-MRI) but there are clinical scenarios in which administration of contrast is not desirable. We investigated performance of the CNN for delineating primary nasopharyngeal carcinoma (NPC) on non-contrast-enhanced images and compared the performance to that on ce-MRI.

MATERIALS AND METHODS

We retrospectively analyzed primary NPC in 195 patients using a well-established CNN, U-Net, for tumor delineation on the non-contrast-enhanced fat-suppressed (fs)-T2W, ce-T1W and ce-fs-T1W images. The CNN-derived delineations were compared to manual delineations to obtain Dice similarity coefficient (DSC) and average surface distance (ASD). The DSC and ASD on fs-T2W were compared to those on ce-MRI. Primary tumor volumes (PTVs) of CNN-derived delineations were compared to that of manual delineations.

RESULTS

The CNN for NPC delineation on fs-T2W images showed similar DSC (0.71 ± 0.09) and ASD (0.21 ± 0.48 cm) to those on ce-T1W images (0.71 ± 0.09 and 0.17 ± 0.19 cm, respectively) (p > 0.05), and lower DSC but similar ASD to ce-fs-T1W images (0.73 ± 0.09, p < 0.001; and 0.17 ± 0.20 cm, p > 0.05). The CNN overestimated PTVs on all sequences (p < 0.001).

CONCLUSION

The CNN showed promise for NPC delineation on fs-T2W images in cases where it is desirable to avoid contrast agent injection. The CNN overestimated PTVs on all sequences.

Targeting the PD-1/ PD-L1 interaction in nasopharyngeal carcinoma

Upregulation of the programmed cell death receptor-1 and ligand (PD-1/PD-L1) pathway is one of many possible mechanisms of immune-evasion relevant to Epstein-Barr virus (EBV)- associated nasopharyngeal cancer (NPC). The therapeutic targeting of the PD-1/ PD-L1 axis is an area of active research in NPC and at least 8 monoclonal or bi-specific antibodies targeting this axis are currently under clinical evaluation in some of the following clinical settings: (1) palliative treatment of recurrent and/or metastatic (R/M) disease; (2) radical treatment of locoregionally advanced disease in adjunct to conventional chemoradiotherapy; (3) local/ regional recurrence. PD-1 antibodies as monotherapy has been reported to yield an overall objective response in around 20-30% of patients with R/M NPC in single-armed phase II trials, and the predictive role of PD-L1 expression in NPC remains to be defined. As with other solid tumors, combinatorial strategies with cytotoxic chemotherapy, radiotherapy or other immunotherapeutic agents (such as other immune-checkpoint inhibitors, EBV-targeting cellular therapy and other immune-modulating agents) and vascular endothelial growth factor/receptor antibodies are actively being evaluated in clinical trials with single-armed or randomized designs. This article will review the scientific rationale of targeting the PD1/PD-L1 axis in NPC, and summarizes the latest trials involving these agents and predictive biomarkers of response to PD-1/PD-L1 antibodies in NPC.

Modified reduced-volume intensity-modulated radiation therapy in non-metastatic nasopharyngeal carcinoma: A prospective observation series

BACKGROUND AND PURPOSE

Although the efficacy of "reduced-volume intensity-modulated radiation therapy (IMRT)" in nasopharyngeal carcinoma (NPC) has been confirmed, two issues regarding the necessity of clinical target volume 1(CTV1) delineation and the optimal margin of CTV2 remained undetermined. The current series, utilized de-intensification technique that omitted the contouring of CTV1 and narrowed the margin of CTV2 from 10 mm to 8 mm, namely "modified reduced-volume IMRT" was initiated to evaluate the efficacy and feasibility of this renew technique in a prospective series.

PATIENTS AND MATERIALS

Dosimetric analysis was performed in 40 non-metastatic NPC cases to evaluate whether our modification is feasible. Then this de-intensification technique was applied in non-metastatic NPC patients treated in our attending group since late 2014. Survival outcomes focused on local recurrence-free survival (LRFS) and local failure pattern were analyzed.

RESULTS

Preliminary dosimetric evaluation of "modified reduced-volume IMRT" showed that the 60 Gy isodose curve generated naturally by this technique could well wrap the target area of CTV1. Subsequent observation series, which included a total of 471 patients and had a median follow-up time of 46.2 months(range,3.7-70.8 months), reported that 4-year estimated LRFS, regional recurrence-free survival (RRFS), distant metastasis-free survival (DMFS) and overall survival (OS) were 96.6%, 97.7%, 87.7% and 92.4%, respectively. All local recurrence lesions occurred within 95% isodose lines and were considered in-field failures.

CONCLUSIONS

Our de-intensification technique "modified reduced-volume IMRT" was feasible and did not compromise therapeutic efficacy, well-designed multicenter prospective trials are needed for further research.

Targeting Epstein-Barr virus oncoprotein LMP1-mediated high oxidative stress suppresses EBV lytic reactivation and sensitizes tumors to radiation therapy

Generating oxidative stress is a critical mechanism by which host cells defend against infection by pathogenic microorganisms. Radiation resistance is a critical problem in radiotherapy against cancer. Epstein-Barr virus (EBV) is a cancer-causing virus and its reactivation plays an important role in the development of EBV-related tumors. This study aimed to explore the inner relationship and regulatory mechanism among oxidative stress, EBV reactivation, and radioresistance and to identify new molecular subtyping models and treatment strategies to improve the therapeutic effects of radiotherapy.

Methods: ROS, NADP⁺/NADPH, and GSSG/GSH were detected to evaluate the oxidative stress of cells. 8-OHdG is a reliable oxidative stress marker to evaluate the oxidative stress in patients. Its concentration in serum was detected using an ELISA method and in biopsies was detected using IHC. qPCR array was performed to evaluate the expression of essential oxidative stress genes. qPCR, Western blot, and IHC were used to measure the level of EBV reactivation in vitro and in vivo. A Rta-IgG ELISA kit and EBV DNA detection kit were used to analyze the reactivation of EBV in serum from NPC patients. NPC tumor tissue microarrays was used to investigate the prognostic role of oxidative stress and EBV reactivation. Radiation resistance was evaluated by a colony formation assay. Xenografts were treated with NAC, radiation, or a combination of NAC and radiation. EBV DNA load of tumor tissue was evaluated using an EBV DNA detection kit. Oxidative stress, EBV reactivation, and the apoptosis rate in tumor tissues were detected by using 8-OHdG, EAD, and TUNEL assays, respectively.

Results: We found that EBV can induce high oxidative stress, which promotes its reactivation and thus leads to radioresistance. Basically, EBV caused NPC cells to undergo a process of 'Redox Resetting' to acquire a new redox status with higher levels of ROS accumulation and stronger antioxidant systems by increasing the expression of the ROS-producing enzyme, NOX2, and the cellular master antioxidant regulator, Nrf2. Also, EBV encoded driving protein LMP1 promotes EBV reactivation through production of ROS. Furthermore, high oxidative stress and EBV reactivation were positively associated with poor overall survival of patients following radiation therapy and were significant related to NPC patients' recurrence and clinical stage. By decreasing oxidative stress using an FDA approved antioxidant drug, NAC, sensitivity of tumors to radiation was increased. Additionally, 8-OHdG and EBV DNA could be dual prognostic markers for NPC patients.

Conclusions: Oxidative stress mediates EBV reactivation and leads to radioresistance. Targeting oxidative stress can provide therapeutic benefits to cancer patients with radiation resistance. Clinically, we, for the first time, generated a molecular subtyping model for NPC relying on 8-OHdG and EBV DNA level. These dual markers could identify patients who are at a high risk of poor outcomes but who might benefit from the sequential therapy of reactive oxygen blockade followed by radiation therapy, which provides novel perspectives for the precise treatment of NPC.

Clinical characteristics and survival outcomes of ascending, descending and mixed types of nasopharyngeal carcinoma in the non-endemic areas of china: A propensity score matching analysis

Purpose

To compare the clinical characteristics and survival outcomes of patients with ascending type (type A), descending type (type D), and mixed type (type AD) of nasopharyngeal carcinoma (NPC) in non‐endemic areas.

Materials and methods

The cohort included 628 patients diagnosed with type A, type D, and type AD of NPC between January 2009 and December 2014. Type A was defined as T_3‐4 N_0‐1, type D as T_0‐1 N_2‐3, and type AD as T_3‐4 N_2‐3. Propensity score matching (PSM) was performed to balance clinical factors and match patients. Kaplan‐Meier methods and Cox proportional hazards models were used to evaluate the impact of different NPC types on survival outcomes.

Results

There were 145 patients with type A, 194 with type D, and 289 with type AD. However, after PSM, there were only 130 patients with each type. Compared with patients with type A, those with type D had lower 5‐year disease‐specific survival (96.9% vs 91.5%) and distant metastasis‐free survival (92.3% vs 77.7%) and higher local relapse‐free survival (88.5% vs 96.9%) (p < 0.05 for all). Patients with type AD may have an increased risk of disease progression (progression‐free survival, 56.9% vs 74.6% and 66.2%) and death (overall survival [OS], 76.9% vs 85.4% and 85.4%) (p < 0.05 for all) compared to patients with the other two types of tumors.

We further analyzed the metastasis trend. Similar metastasis patterns were observed in types AD and D, and types AD and A had similar recurrence trends. The mortality rate of patients with types AD and D in the first 3 years after metastasis was remarkably higher than that of patients with type A.

Conclusions

In non‐endemic areas of China, metastases and recurrence patterns differed across tumor types. Type AD has the worst OS, and the clinical process is more radical. Type D has a lower recurrence rate, higher metastasis, and disease‐related mortality rates, and poorer prognosis after metastasis than type A.

Exploring MRI based radiomics analysis of intratumoral spatial heterogeneity in locally advanced nasopharyngeal carcinoma treated with intensity modulated radiotherapy

Background

We hypothesized that spatial heterogeneity exists between recurrent and non-recurrent regions within a tumor. The aim of this study was to determine if there is a difference between radiomics features derived from recurrent versus non recurrent regions within the tumor based on pre-treatment MRI.

Methods

A total of 14 T4NxM0 NPC patients with histologically proven “in field” recurrence in the post nasal space following curative intent IMRT were included in this study. Pretreatment MRI were co-registered with MRI at the time of recurrence for the delineation of gross tumor volume at diagnosis(GTV) and at recurrence(GTVr). A total of 7 histogram features and 40 texture features were computed from the recurrent(GTVr) and non-recurrent region(GTV-GTVr). Paired t-tests and Wilcoxon signed-rank tests were carried out on the 47 quantified radiomics features.

Results

A total of 7 features were significantly different between recurrent and non-recurrent regions. Other than the variance from intensity-based histogram, the remaining six significant features were either from the gray-level size zone matrix (GLSZM) or the neighbourhood gray-tone difference matrix (NGTDM).

Conclusions

The radiomic features extracted from pre-treatment MRI can potentially reflect the difference between recurrent and non-recurrent regions within a tumor and has a potential role in pre-treatment identification of intra-tumoral radio-resistance for selective dose escalation.

Glutamine Synthetase Promotes Radiation Resistance via Facilitating Nucleotide Metabolism and Subsequent DNA Damage Repair

Radiation resistance is a critical problem in radiotherapy for cancer. Radiation kills tumor cells mainly through causing DNA damage. Thus, efficiency of DNA damage repair is one of the most important factors that limits radiotherapy efficacy. Glutamine physiologically functions to generate protein and nucleotides. Here, we study the impact of glutamine metabolism on cancer therapeutic responses, in particular under irradiation-induced stress. We show that radiation-resistant cells possessed low glycolysis, mitochondrial respiration, and TCA cycle but high glutamine anabolism. Transcriptome analyses revealed that glutamine synthetase (GS), an enzyme catalyzing glutamate and ammonia to glutamine, was responsible for the metabolic alteration. ChIP and luciferase reporter assays revealed that GS could be transcriptionally regulated by STAT5. Knockdown of GS delayed DNA repair, weakened nucleotide metabolism, and enhanced radiosensitivity both in vitro and in vivo. Our data show that GS links glutamine metabolism to radiotherapy response through fueling nucleotide synthesis and accelerating DNA repair.

Effect of relevant factors on radiation-induced nasopharyngeal ulcer in patients with primary nasopharyngeal carcinoma treated with intensity-modulated radiation therapy

OBJECTIVE

To analyze the correlation between relevant factors and radiation-induced nasopharyngeal ulcer (RINU) in primary nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiation therapy (IMRT).

METHODS

Clinical data were collected for 599 patients with newly diagnosed NPC who had completed IMRT. The entire cohort was randomly divided into two subgroups. The relationship between RINU and IMRT dose-volume were statistically analyzed with ROC curves and the Chi-square test. Nutritional status during and after treatment was compared between patients with vs without RINU.

RESULTS

The results obtained showed that dose-volume had no effect on the incidence of RINU (P > .05). Nutrition-related parameters differed significantly between patients with vs without RINU (P < .05).

CONCLUSION

The results obtained show that the incidence of RINU is not related to IMRT dose-volume in the treatment of primary NPC. The incidence of RINU was found to be related to nutritional status during and after radiation therapy.

LEVEL OF EVIDENCE

2a.

Local and Lymph Node Relapse of Nasopharyngeal Carcinoma: A Single-Center Experience

OBJECTIVES

The study aimed to investigate the epidemiological and clinical characteristics as well as the therapeutic results in patients with locoregional (LR) relapse after treatment of nasopharyngeal carcinoma (NPC).

METHODS

We retrospectively reviewed the medical records of patients with local and/or regional recurrent NPC over 13 years (2003-2015).

RESULTS

Twenty-five patients were treated for local or/and local-regional recurrence of NPC. The rate of LR relapse was 7.2%. The mean age of the patients was 46 ± 13.9 years. The median time to relapse was 25 months. The recurrence was nasopharyngeal in 17 patients, nasopharyngeal and neck lymph nodes in 7 patients, and neck lymph nodes in 1 patient. Fifteen relapsed patients had a locally advanced disease (rT3-rT4). Patients who had initially T1 or T2 tumor had a locally advanced relapsed disease (rT3rT4) in 27.3% and patients whose disease was initially classified as T3 or T4 had a locally advanced relapsed disease (rT3T4) in 85.7% (P = .005, Fisher test). Twelve patients had chemotherapy after relapse. Chemotherapy was followed by concurrent chemoradiotherapy in 3 patients and by radiotherapy (RT) in 4 patients. Nine patients had concurrent chemoradiotherapy and 1 patient had exclusive RT. The overall survival (OS) at 1 year, 3 years, and 5 years was, respectively, 58%, 18%, and 10%. The OS was significantly higher in patients with good performance status at the time of relapse (World Health Organization = 1; P = .01) and in patients with late relapse (after 2 years; P = .03).

CONCLUSIONS

Locoregional relapse rate in our study was 7.2%. Locoregional reirradiation was the mainstay treatment modality in relapsed NPC. Relapsed NPC had a poor prognosis with a 5-year survival rate of 18%. The OS was significantly higher in patients with good performance status and in patients with late relapse (after 2 years).

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

Background

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

Methods

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

Results

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

Conclusions

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

Analysis of Clinical Target Volume Delineation in Local-regional Failure of Nasopharyngeal Carcinoma after Intensity-modulated Radiotherapy

OBJECTIVE: To analyze the pattern of local failure in patients with nasopharyngeal carcinoma (NPC) after intensity-modulated radiotherapy (IMRT) and find a more reasonable delineation of the clinical target volume (CTV).

METHODS AND MATERIALS: A total of 212 patients with non-metastatic NPC who underwent IMRT were analyzed. Radiation therapy was run at a total dose of 66-74 Gy (2.0-2.2 Gy fractions). The follow-up of local recurrence and the recurrence-related features were analyzed for the original treatment situation. The failures were delimited as “in-field failure” if V_recur within the 95% isodose curve (V95%) was ≥95%; “marginal failure” if V95% was less than 95% and not less than 20%; or “out-field failure” if V95% was< 20%. Kaplan-Meier method was used to calculate the survival rates.

RESULTS: The median follow-up was 43.4 months. The 5-year local relapse-free survival and overall survival rates were 85.6 and 77.8%, respectively. A total of 18 patients have relapsed. The in-field failure, marginal failure, and out-field failure accounted for 83.3%, 11.1%, and 5.6%, respectively. The site of recurrence was basically in the high dose area.

CONCLUSION: These findings suggested that IMRT provide a good local control for patients with NPC, and the in-field failure is the main mode. A wide range of CTV cannot prevent the local recurrence, narrowing the CTV to protect the adjacent organs should be taken into consideration.

Management of locally recurrent nasopharyngeal carcinoma

As a consequence of the current excellent loco-regional control rates attained using the generally accepted treatment paradigms involving intensity-modulated radiotherapy for nasopharyngeal carcinoma (NPC), only 10-20% of patients will suffer from local and/or nodal recurrence after primary treatment. Early detection of recurrence is important as localized recurrent disease is still potentially salvageable, but this treatment often incurs a high risk of major toxicities. Due to the possibility of radio-resistance of tumors which persist or recur despite adequate prior irradiation and the limited tolerance of adjacent normal tissues to sustain further additional treatment, the management of local failures remains one of the greatest challenges in this disease. Both surgical approaches for radical resection and specialized re-irradiation modalities have been explored. Unfortunately, available data are based on retrospective studies, and the majority of them are based on a small number of patients or relatively short follow-up. In this article, we will review the different salvage treatment options and associated prognostic factors for each of them. We will also propose a treatment algorithm based on the latest available evidence and discuss the future directions of treatment for locally recurrent NPC.

Metabolic tumor volume and conformal radiotherapy based on prognostic PET/CT for treatment of nasopharyngeal carcinoma

For patients with nasopharyngeal carcinoma (NPC), prognostic indicators to customize subsequent biologically conformal radiation therapy may be obtained via 2-(fluorine-18)-fluoro-2-deoxy-D-glucose (F-FDG) positron emission tomography/computed tomography (PET/CT). This retrospective study assessed the prognostic significance and feasibility of conformal radiotherapy for NPC, based on F-FDG PET/CT. Eighty-two patients with NPC underwent F-FDG PET/CT prior to intensity-modulated radiation therapy (IMRT). The maximum standardized uptake value (SUVmax) and metabolic tumor volume (MTV) of the primary tumor were measured, with MTVx based on absolute SUVx values ≥ specific threshold x on each axial image. The cut-off SUVmax and MTV values for predicting 3-year progression-free survival (PFS) were calculated according to a receiver operating characteristic curve. Assessed were correlations between SUVmax and MTV and between threshold x and MTVx, and the MTV percentage of the primary tumor volume at threshold x. The SUVmax and MTV were positively associated, as were MTV and primary tumor volume. Primary tumor volume, SUVmax, and MTV were significant predictors of survival. The 3-year PFS rates for SUVmax ≤8.20 and >8.20 were 91.1% and 73.0%, respectively (P = .027). With furthermore analysis, patients having tumor with smaller MTV had higher 3-year PFS than patients having tumor with larger MTV. The 3-year PFS rate was inversely related to MTV. SUVmax and MTV, derived by PET/CT, are important for assessing prognosis and planning radiotherapy for patients with NPC. Small MTV indicated better 3-year PFS compared with large MTV. For the best therapeutic effect, MTV4.0 was the best subvolume to determine radiotherapy boost.

Clinical and dosimetric predictors of physician and patient reported xerostomia following intensity modulated radiotherapy for nasopharyngeal cancer - A prospective cohort analysis

BACKGROUND AND PURPOSE

To compare physician and patient reported xerostomia and correlate xerostomia with dosimetric and clinical parameters for nasopharyngeal cancer (NPC) patients treated with intensity modulated radiotherapy (IMRT) and chemotherapy.

PATIENTS AND METHODS

We analyzed the data of 172 patients with locally advanced NPC. Xerostomia was evaluated via physician-rated xerostomia based on RTOG morbidity score (E1), patient-rated dry mouth (E2) and patient-rated sticky saliva (E3) based on EORTC QLQ-HN35 questionnaire. Primary endpoint was the presence of moderate to severe xerostomia at 2-year after completion of IMRT.

RESULTS

The levels of physician reported xerostomia (E1) were consistently lower than patient reported dry mouth (E2) over time. The incidence of patients with xerostomia at 3-month post RT was 58% based on E1, 70% based on E2, and 51% based on E3. The corresponding incidence rates at 2-year post RT was 26% (E1), 36% (E2) and 21% (E3). The incidence of patients with xerostomia at 1-year post RT was close to that at 2-year post RT for all the 3 endpoints. The average Dmean of parotid glands was 41.5 Gy (range: 31.0 Gy-65.9 Gy, median: 40.7 Gy). No dosimetric parameters were significantly associated with xerostomia.

CONCLUSION

Significant proportion of patients still experienced long term xerostomia with IMRT. Dose-effect relationships between xerostomia and the parotid glands were not observed in this study.

Post-radiation sinusitis is associated with recurrence in nasopharyngeal carcinoma patients treated with intensity-modulated radiation therapy

BACKGROUND

This study investigated the impact of post-radiation sinusitis on the prognosis of nasopharyngeal carcinoma (NPC) patients treated with intensity-modulated radiation therapy (IMRT).

METHODS

Two hundred and thirty patients with non-metastatic NPC were analyzed in terms of freedom from local failure (FFLF), freedom from distant failure (FFDF), overall survival (OS), and disease-free survival (DFS). For each patient, the status of the sinus mucosa was flexibly assessed by documenting mucosal changes as indicated by differences between images obtained before radiotherapy and more than 6 months post-radiation.

RESULTS

With a median follow-up of 39.7 months (8 to 81 months), 19 (8.26%) patients relapsed locally, 13 (5.65%) patients failed in the neck, and 26 (11.3%) patients developed distant metastases. The presence of sinusitis noted in images post-radiation was a significant predictor for DFS (p = 0.001), FFLF (p = 0.004), and FFDF (p = 0.015), in addition to having high negative predictive value for local relapse (97.5%).

CONCLUSIONS

This is the first study to investigate the prognostic value of post-radiation sinusitis in NPC patients treated with IMRT. Post-radiation sinusitis was found to be a significant predictor for DFS, FFLF, and FFDF, and was also found to have high negative predictive value for local recurrence (97.5%). It may thus be used as an additional tool for clinicians to determine the possibility of recurrence.

Locoregional Control and Mild Late Toxicity After Reducing Target Volumes and Radiation Doses in Patients With Locoregionally Advanced Nasopharyngeal Carcinoma Treated With Induction Chemotherapy (IC) Followed by Concurrent Chemoradiotherapy: 10-Year Results of a Phase 2 Study

PURPOSE

To evaluate the long-term locoregional control, failure patterns, and late toxicity after reducing the target volume and radiation dose in patients with locoregionally advanced nasopharyngeal carcinoma patients treated with induction chemotherapy (IC) plus concurrent chemoradiotherapy (CCRT).

METHODS AND MATERIALS

Previously untreated patients with locoregionally advanced nasopharyngeal carcinoma were recruited into this prospective study. All patients received 2 cycles of IC followed by CCRT. The gross tumor volumes of the nasopharynx (GTVnx) and the neck lymph nodes (GTVnd) were delineated according to the post-IC tumor extension and received full therapeutic doses (68 Gy and 62-66 Gy, respectively). The primary tumor shrinkage after IC was included in the high-risk clinical target volume (CTV1) with a reduced dose of 60 Gy. The locoregional recurrence-free survival (LRRFS), distant metastasis-free survival (DMFS), and overall survival (OS) were calculated using the Kaplan-Meier method. The location and extent of locoregional recurrences were transferred to pretreatment planning computed tomography for dosimetry analysis.

RESULTS

There were 112 patients enrolled in this study. The average mean dose of post-GTVnx, post-GTVnd (left), post-GTVnd (right), post-CTV1, and post-low-risk clinical target volume (CTV2) was 75.24, 68.97, 69.16, 70.49, and 63.37 Gy, respectively. With a median follow-up of 125.95 months, the 10-year LRRFS, DMFS and OS were 89.0%, 83.3%, and 75.9%, respectively. There were 8 local recurrences and 6 regional recurrences in 12 patients. All 8 of the local recurrences were in-field; among the 6 regional recurrences, 4 were in-field, 1 was marginal, and 1 was out-field. The most common late toxicities were grade 1 to 2 subcutaneous fibrosis, hearing loss, and xerostomia. No grade 4 late toxicities were observed.

CONCLUSIONS

Reduction of the target volumes according to the post-IC tumor extension and radiation dose to the post-IC tumor shrinkage could yield excellent long-term locoregional control with limited marginal and out-field recurrences and mild late toxicities.

Pretreatment MRI radiomics analysis allows for reliable prediction of local recurrence in non-metastatic T4 nasopharyngeal carcinoma

BACKGROUND

To identify a radiomics signature to predict local recurrence in patients with non-metastatic T4 nasopharyngeal carcinoma (NPC).

METHODS

A total of 737 patients from Sun Yat-sen University Cancer Center (training cohort: n = 360; internal validation cohort: n = 120) and Wuzhou Red Cross Hospital (external validation cohort: n = 257) underwent feature extraction from the largest axial area of the tumor on pretreatment magnetic resonance imaging scans. Feature selection was based on the prognostic performance and feature stability in the training cohort. Radscores were generated using the Cox proportional hazards regression model with the selected features in the training cohort and then validated in the internal and external validation cohorts. We also constructed a nomogram for predicting local recurrence-free survival (LRFS).

FINDINGS

Eleven features were selected to construct the Radscore, which was significantly associated with LRFS. For the training, internal validation, and external validation cohorts, the Radscore (C-index: 0.741 vs. 0.753 vs. 0.730) outperformed clinical prognostic variables (C-index for primary gross tumor volume: 0.665 vs. 0.672 vs. 0.577; C-index for age: 0.571 vs. 0.629 vs. 0.605) in predicting LRFS. The generated radiomics nomogram, which integrated the Radscore and clinical variables, exhibited a satisfactory prediction performance (C-index: 0.810 vs. 0.807 vs. 0.753). The nomogram-defined high-risk group had a shorter LRFS than did the low-risk group (5-year LRFS: 73.6% vs. 95.3%, P < .001; 79.6% vs 95.8%, P = .006; 85.7% vs 96.7%, P = .005).

INTERPRETATION

The Radscore can reliably predict LRFS in patients with non-metastatic T4 NPC, which might guide individual treatment decisions. FUND: This study was funded by the Health & Medical Collaborative Innovation Project of Guangzhou City, China.

Deep Learning for Automated Contouring of Primary Tumor Volumes by MRI for Nasopharyngeal Carcinoma

Background Nasopharyngeal carcinoma (NPC) may be cured with radiation therapy. Tumor proximity to critical structures demands accuracy in tumor delineation to avoid toxicities from radiation therapy; however, tumor target contouring for head and neck radiation therapy is labor intensive and highly variable among radiation oncologists. Purpose To construct and validate an artificial intelligence (AI) contouring tool to automate primary gross tumor volume (GTV) contouring in patients with NPC. Materials and Methods In this retrospective study, MRI data sets covering the nasopharynx from 1021 patients (median age, 47 years; 751 male, 270 female) with NPC between September 2016 and September 2017 were collected and divided into training, validation, and testing cohorts of 715, 103, and 203 patients, respectively. GTV contours were delineated for 1021 patients and were defined by consensus of two experts. A three-dimensional convolutional neural network was applied to 818 training and validation MRI data sets to construct the AI tool, which was tested in 203 independent MRI data sets. Next, the AI tool was compared against eight qualified radiation oncologists in a multicenter evaluation by using a random sample of 20 test MRI examinations. The Wilcoxon matched-pairs signed rank test was used to compare the difference of Dice similarity coefficient (DSC) of pre- versus post-AI assistance. Results The AI-generated contours demonstrated a high level of accuracy when compared with ground truth contours at testing in 203 patients (DSC, 0.79; 2.0-mm difference in average surface distance). In multicenter evaluation, AI assistance improved contouring accuracy (five of eight oncologists had a higher median DSC after AI assistance; average median DSC, 0.74 vs 0.78; P < .001), reduced intra- and interobserver variation (by 36.4% and 54.5%, respectively), and reduced contouring time (by 39.4%). Conclusion The AI contouring tool improved primary gross tumor contouring accuracy of nasopharyngeal carcinoma, which could have a positive impact on tumor control and patient survival. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Chang in this issue.

Use of Radiomics Combined With Machine Learning Method in the Recurrence Patterns After Intensity-Modulated Radiotherapy for Nasopharyngeal Carcinoma: A Preliminary Study

Objective: To analyze the recurrence patterns and reasons in patients with nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiotherapy (IMRT) and to investigate the feasibility of radiomics for analysis of radioresistance.

Methods: We analyzed 306 NPC patients treated with IMRT from Jul-2009 to Aug-2016, 20 of whom developed with recurrence. For the NPCs with recurrence, CT, MR, or PET/CT images of recurrent disease were registered with the primary planning CT for dosimetry analysis. The recurrences were defined as in-field, marginal or out-of-field, according to dose-volume histogram (DVH) of the recurrence volume. To explore the predictive power of radiomics for NPCs with in-field recurrences (NPC-IFR), 16 NPCs with non-progression disease (NPC-NPD) were used for comparison. For these NPC-IFRs and NPC-NPDs, 1117 radiomic features were quantified from the tumor region using pre-treatment spectral attenuated inversion-recovery T2-weighted (SPAIR T2W) magnetic resonance imaging (MRI). Intraclass correlation coefficients (ICC) and Pearson correlation coefficient (PCC) was calculated to identify influential feature subset. Kruskal-Wallis test and receiver operating characteristic (ROC) analysis were employed to assess the capability of each feature on NPC-IFR prediction. Principal component analysis (PCA) was performed for feature reduction. Artificial neural network (ANN), k-nearest neighbor (KNN), and support vector machine (SVM) models were trained and validated by using stratified 10-fold cross validation.

Results: The median follow up was 26.5 (range 8–65) months. 9/20 (45%) occurred in the primary tumor, 8/20 (40%) occurred in regional lymph nodes, and 3/20 (15%) patients developed a primary and regional failure. Dosimetric and target volume analysis of the recurrence indicated that there were 18 in-field, and 1 marginal as well as 1 out-of-field recurrence. With pre-therapeutic SPAIR T2W MRI images available, 11 NPC-IFRs (11 of 18 NPC-IFRs who had available pre-therapeutic MRI) and 16 NPC-NPDs were subsequently employed for radiomic analysis. Results showed that NPC-IFRs vs. NPC-NPDs could be differentiated by 8 features (AUCs: 0.727–0.835). The classification models showed potential in prediction of NPC-IFR with higher accuracies (ANN: 0.812, KNN: 0.775, SVM: 0.732).

Conclusion: In-field and high-dose region relapse were the main recurrence patterns which may be due to the radioresistance. After integration in the clinical workflow, radiomic analysis can be served as imaging biomarkers to facilitate early salvage for NPC patients who are at risk of in-field recurrence.

Proposal of a Pretreatment Nomogram for Predicting Local Recurrence after Intensity-Modulated Radiation Therapy in T4 Nasopharyngeal Carcinoma: A Retrospective Review of 415 Chinese Patients

PURPOSE

Local relapse-free survival (LRFS) differs widely among patients with T4 category nasopharyngeal carcinoma (NPC). We aimed to build a nomogram incorporating clinicopathological information to predict LRFS in T4 NPC after definitive intensity-modulated radiation therapy (IMRT).

MATERIALS AND METHODS

Retrospective study of 415 Chinese patients with non-metastatic T4 NPC treated with definitive IMRT with or without chemotherapy at our cancer center between October 2009 and September 2013. The nomogram for LRFS at 3 and 5 years was generated based on multivariate Cox proportional hazards regression, and validated using bootstrap resampling, assessing discriminative performance using the concordance index (C-index) and determining calibration ability via calibration curves.

RESULTS

Five-year LRFS was 88.8%. We identified and incorporated four independent prognostic factors for LRFS: ethmoid sinus invasion, primary gross tumor volume, age, and pretreatment body mass index. The C-index of the nomogram for local recurrence was 0.732 (95% confidence interval, 0.726 to 0.738), indicating excellent predictive accuracy. The calibration curve revealed excellent agreement between nomogram-predicted and observed LRFS probabilities. Risk subgroups based on total point score cutoff values enabled effective discrimination of LRFS.

CONCLUSION

This pretreatment nomogram enables clinicians to accurately predict LRFS in T4 NPC after definitive IMRT, and could help to facilitate personalized patient counselling and treatment strategies.

Patterns of local failures and suggestions for reduction of clinical target volume for nasopharyngeal carcinoma patients without cervical lymph node metastasis

BACKGROUND

To demonstrate the robustness of clinical target volume delineation for nasopharyngeal carcinoma (NPC) patients, this study makes a detailed analysis of the initial irradiated dose of the recurrent site and local failure patterns after intensity-modulated radiation therapy (IMRT). Based on this analysis, further improvement of delineation recommendations may be made in order to improve the quality-of-life in NPC, without decreasing the local control and survival rate.

METHODS

In total, 382 newly diagnosed non-metastatic NPC patients were retrospectively enrolled, receiving elective neck irradiation to levels II, III, and VA. For patients with local failure, the location and extent of local failures were transferred to the pretreatment planning computed tomography (CT) for dosimetric analysis. The dose of radiation received by GTVr (gross tumor volume of recurrence) was calculated and analyzed with dose-volume histogram (DVH). Failures were classified as: "in field" if 95% of GTVr was within the 95% isodose, "marginal" if 20%-95% of GTVr was within the 95% isodose, or "outside" if less than 20% of GTVr was inside the 95% isodose.

RESULTS

With a median follow-up time of 61.3 months, 12 patients developed local recurrence (10 cases available). The 5-year overall survival, local relapse-free survival, regional relapse-free survival, distant metastasis failure-free survival, and disease-free survival were 87.8%, 95.2%, 99.1%, 93.3%, and 82.5%, respectively. Dose conformity with IMRT was excellent, and the recurrence was mainly within 3 years after the first treatment. The dosimetric analysis showed that seven failures were classified as "in-field", two failures as "marginal", and only one failure as "out-field". Most local relapse sites located just the same site of primary tumor and most anatomic sites were at low risk of concurrent bilateral tumor invasion.

CONCLUSIONS

IMRT with elective neck irradiation provides excellent local control for NPC patients without cervical lymph node metastasis. In-field failures are the main patterns for local recurrence, and the radioresistant subvolumes within the gross tumor volume are needed to be identified. This study proposed suggestions for reduction of target volume during IMRT treatment for NPC patients.

Investigation of long-term survival outcomes and failure patterns of patients with nasopharyngeal carcinoma receiving intensity-modulated radiotherapy: a retrospective analysis

Intensity-modulated radiotherapy (IMRT) has replaced the conventional radiotherapy (2D-RT) and improved clinical efficacy in Nasopharyngeal Carcinoma (NPC) patients. In the present study, we retrospectively analyzed the clinical characteristics of patients with NPC treated with IMRT to assess the long-term survival outcomes and failure patterns. Of the 527 patients, One hundred and twenty-one patients experienced treatment failure, 86 patients developed distant metastases, and 12 patients developed a second primary tumor. The local and regional recurrence rates were 31.4% and 14.0%, respectively. The 5-year overall survival (OS), progression-free survival (PFS), local recurrence-free survival (LRFS), regional relapse-free survival (RRFS), and distant metastatic relapse-free survival (DMFS) rates were 80.9%, 75.6%, 91.7%, 96.2%, and 83.0%, respectively. The 5-year LRFS rates of Stage T1-4 patients were 100.0%, 93.1%, 92.0%, and 85.8%, respectively. The 5-year DMFS rates of Stage N0-3 patients were 95.0%, 86.1%, 79.5%, and 67.2%, respectively. Multivariate analysis showed age and T-stage were independent predictors of OS, T-stage was an independent predictor of LRFS, and age and N-stage were independent predictors of PFS and DMFS.

In summary, the improved treatment results with IMRT are primarily due to the achievement of a higher local tumor control rate and OS in NPC patients. However, distant metastasis was the most commonly observed failure pattern after treatment. These results provide deep insights about the value of IMRT in the treatment and prognosis of NPC patients.

Optimal cumulative cisplatin dose in nasopharyngeal carcinoma patients receiving additional induction chemotherapy

To clarify the optimal cumulative cisplatin dose (CCD) in locoregionally-advanced nasopharyngel carcinoma (NPC) patients receiving induction chemotherapy (IC) plus concurrent chemoradiotherapy (CCRT). Using the NPC-specific database from the established big-data intelligence platform at Sun Yat-Sen University Cancer Center, 583 non-disseminated, locoregionally-advanced NPC patients receiving IC plus CCRT were enrolled. Propensity score matching (PSM) analysis was conducted to control for confounding factors. The median CCD was 160 mg/m2 after IC (range, 40-300 mg/m2 ); only 74 patients (12.7%) achieved CCD >200 mg/m2 . Patients receiving >200 mg/m2 CCD did not show significantly improved 5-year overall survival (OS) (HR = 1.19; 95% confidence intervals [CI] 0.69-2.06, P = .53) and progression-free survival (PFS) (HR = 1.03; 95% CI: 0.63-1.68, P = .92) compared with patients receiving <200 mg/m2 CCD. Further investigations of the potential of median CCD (160 mg/m2 ) to yield survival benefits revealed that there were no significant differences in survival endpoints between patients receiving CCD >160 mg/m2 and CCD < 160 mg/m2 in both the original and PSM cohorts. In addition, subgroup analysis indicated a favorable PFS, but not OS, with higher cisplatin administration in patients with pretreatment Epstein-Barr virus deoxyribonucleic acid (EBV DNA) <1000 copies/mL (HR = 0.26, 95% CI: 0.07-0.93, P = .03) and receiving <3 IC cycles (HR = 0.59, 95% CI 0.33-1.07, P = .08). Our analysis of real world data provided references for the optimal CCD in locoregionally-advanced NPC receiving additional IC. The causal relationship between 200 mg/m2 CCD and improved survival was not defined; 160 mg/m2 CCD might be enough. However, for patients with EBV DNA <1000 copy/mL and receiving <3 IC cycles, a higher dose might be necessary.

Cycle number of neoadjuvant chemotherapy might influence survival of patients with T1-4N2-3M0 nasopharyngeal carcinoma

Objective

Stage N2-3 nasopharyngeal carcinoma (NPC) shows a high risk of distant metastasis, which will finally cause death. This study aimed to evaluate the impact of neoadjuvant chemotherapy (NACT) of various cycles before radical radiotherapy on distant metastasis and survival of patients with stage N2-3 diseases.

Methods

In this study, a total of 1,164 consecutive patients with non-metastatic N2-3 NPC were recruited and prospectively observed. Then 231 patients who received NACT of 4 cycles (NACT=4 group) were matched 1:2:1 to 462 patients treated with NACT of 2 cycles (NACT=2 group) and 231 patients treated without NACT (NACT=0 group), according to age, histological subtype, N stage and NACT regimen. Five candidate variables (sex, T stage, concurrent chemotherapy, intensity-modulated radiation therapy and cycle number of NACT) were analyzed for their association with patients' survival.

Results

After matching, the overall survival (OS), disease-free survival (DFS), local-recurrence-free survival (RFS) and distant-metastasis-free survival (MFS) of the NACT=4 group (89.2%, 81.0%, 83.3% and 84.8%, respectively) were better than those of the NACT=2 group (83.3%, 72.5%, 81.2% and 77.9%, respectively) and the NACT=0 group (74.0%, 63.2%, 74.0% and 68.8%, respectively). In multivariate analysis, the cycle number of NACT maintained statistical significance on the OS, DFS, RFS and MFS (all P<0.05).

Conclusions

For N2-3 NPC, cycle number of NACT appeared to be an independent factor associated with an improvement of survival.

Clinical Analysis of Recurrence Patterns in Patients With Nasopharyngeal Carcinoma Treated With Intensity-Modulated Radiotherapy

OBJECTIVE

To evaluate the characteristics and risk factors for locoregional recurrence in patients with nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiotherapy (IMRT).

METHODS

The clinical diagnosis and treatment data of 195 patients with NPC treated with IMRT from March 2005 to May 2010 (including 9, 24, 70, and 92 cases of stage I, II, III, and IV disease, respectively, according to the 7th edition American Joint Committee on Cancer staging criteria) were retrospectively analyzed. The Kaplan-Meier method was used for survival analysis, and logistic regression was used to conduct univariate and multivariate analyses.

RESULTS

The 5-year recurrence rate was 10.8%, and the 5-year local and regional recurrence rates were 8.7% and 3.4%, respectively. Multivariate analysis showed that the short axis of the cervical lymph nodes (≥3 cm) was an influencing factor for regional lymph node recurrence after IMRT.

CONCLUSION

In-field and high-dose region failures were the main patterns associated with local-regional recurrence, and nasopharyngeal recurrence was most commonly detected. Newly diagnosed patients with large cervical lymph nodes (short diameter ≥3 cm) should be carefully followed up considering regional lymph node recurrence.

Pretreatment Nomograms for Local and Regional Recurrence after Radical Radiation Therapy for Primary Nasopharyngeal Carcinoma

Background: The aim of this study was to build nomograms to predict local recurrence (LR) and regional recurrence (RR) in patients with nasopharyngeal carcinoma (NPC) underwent intensity-modulated radiation therapy (IMRT).

Patients and Methods: A total of 1811 patients with non-metastatic NPC treated with IMRT (with or without chemotherapy) between October 2009 and February 2012 at our center were involved for building the nomograms. Nomograms for LR-free rate and RR-free rate at 3- and 5- year were generated as visualizations of Cox proportional hazards regression models, and validated using bootstrap resampling, estimating discrimination and calibration.

Results: With a median follow up of 49.50 months, the 3- and 5- year LR-free rate were 95.43% and 94.30% respectively; the 3- and 5- year RR-free rate were 95.94% and 95.41% respectively. The final predictive model for LR included age, the neutrophil/leukocyte ratio (NWR), pathological type, primary gross tumor volume, maxillary sinus invasion, ethmoidal sinus invasion and lacerated foramen invasion; the model for RR involved NWR, plasma Epstein-Barr virus (EBV) DNA copy number, cervical lymph node volume and N category. The models showed fairly good discriminatory ability with concordance indices (c-indices) of 0.76 and 0.74 for predicting LR and RR, respectively, as well as good calibration. The proposed stratification of risk groups based on the nomograms allowed significant distinction between Kaplan-Meier curves for LR and RR.

Conclusions: The proposed nomograms resulted in more-accurate prognostic prediction for LR and RR with a high concordance, hence to inform patients with high risk of recurrence on more aggressive therapy. The prognostic nomograms could better stratify patients into different risk groups.

Comparative diagnostic value of 18F-fluoride PET-CT versus MRI for skull-base bone invasion in nasopharyngeal carcinoma

PURPOSE

This study compared the diagnostic value of F-fluoride PET-computed tomography (PET-CT) and MRI in skull-base bone erosion in nasopharyngeal carcinoma (NPC) patients.

METHODS

A total of 93 patients with biopsy-confirmed NPC were enrolled, including 68 men and 25 women between 23 and 74 years of age. All patients were evaluated by both F-fluoride PET-CT and MRI, and the interval between the two imaging examinations was less than 20 days. The patients received no treatment either before or between scans. The studies were interpreted by two nuclear medicine physicians or two radiologists with more than 10 years of professional experience who were blinded to both the diagnosis and the results of the other imaging studies. The reference standard was skull-base bone erosion at a 20-week follow-up imaging study.

RESULTS

On the basis of the results of the follow-up imaging studies, 52 patients showed skull-base bone erosion. The numbers of true positives, false positives, true negatives, and false negatives with F-fluoride PET-CT were 49, 4, 37, and 3, respectively. The numbers of true positives, false positives, true negatives, and false negatives with MRI were 46, 5, 36, and 6, respectively. The sensitivity, specificity, and crude accuracy of F-fluoride PET-CT were 94.23, 90.24, and 92.47%, respectively; for MRI, these values were 88.46, 87.80, and 88.17%. Of the 52 patients, 43 showed positive findings both on F-fluoride PET-CT and on MRI. Within the patient cohort, F-fluoride PET-CT and MRI detected 178 and 135 bone lesions, respectively.

CONCLUSION

Both F-fluoride PET-CT and MRI have high sensitivity, specificity, and crude accuracy for detecting skull-base bone invasion in patients with NPC. F-fluoride PET-CT detected more lesions than did MRI in the skull-base bone. This suggests that F-fluoride PET-CT has a certain advantage in evaluating the skull-base bone of NPC patients. Combining the two methods could improve the diagnostic accuracy of skull-base bone invasion for NPC.

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

Background

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

Methods

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

Results

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

Conclusion

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

The impact of positron emission tomography on primary tumour delineation and dosimetric outcome in intensity modulated radiotherapy of early T-stage nasopharyngeal carcinoma

Background

In intensity modulated radiotherapy (IMRT) of nasopharyngeal carcinoma (NPC), accurate delineation of the gross tumour volume (GTV) is important. Image registration of CT and MRI has been routinely used in treatment planning. With recent development of positron emission tomography (PET), the aims of this study were to evaluate the impact of PET on GTV delineation and dosimetric outcome in IMRT of early stage NPC patients.

Methods

Twenty NPC patients with T1 or T2 disease treated by IMRT were recruited. For each patient, 2 sets of NP GTVs were delineated separately, in which one set was performed using CT and MRI registration only (GTV_CM), while the other set was carried out using PET, CT and MRI information (GTV_CMP). A 9-field IMRT plan was computed based on the target volumes generated from CT and MRI (PTV_CM). To assess the geometric difference between the GTV_CM and GTV_CMP, GTV volumes and DICE similarity coefficient (DSC), which measured the geometrical similarity between the two GTVs, were recorded. To evaluate the dosimetric impact, the D_max, D_min, D_mean and D₉₅ of PTVs were obtained from their dose volume histograms generated by the treatment planning system.

Results

The overall mean volume of GTV_CMP was greater than GTV_CM by 4.4 %, in which GTV_CMP was slightly greater in the T1 group but lower in the T2 group. The mean DSC of the whole group was 0.79 ± 0.05. Similar mean DSC values were also obtained from the T1 and T2 groups separately. The dosimetric parameters of PTV_CM fulfilled the planning requirements. When applying this plan to the PTV_CMP, the average D_min (56.9 Gy) and D₉₅ (68.6 Gy) of PTV_CMP failed to meet the dose requirements and demonstrated significant differences from the PTV_CM (p = 0.001 and 0.016 respectively), whereas the doses to GTV_CMP did not show significant difference with the GTV_CM.

Conclusion

In IMRT of early stage NPC, PET was an important imaging modality in radiotherapy planning so as to avoid underdosing the PTV, although its effect on GTV delineation was not significant. It was recommended that PET images should be included in the treatment planning of NPC patients.

Tolfenamic Acid Inhibits the Proliferation, Migration, and Invasion of Nasopharyngeal Carcinoma: Involvement of p38-Mediated Down-Regulation of Slug

PURPOSE

Tolfenamic acid (TA), a non-steroidal anti-inflammatory drug, is known to exhibit antitumor effects in various cancers apart from nasopharyngeal cancer (NPC). NPC exhibits high invasiveness, as well as metastatic potential, and patients continue to suffer from residual, recurrent, or metastatic disease even after chemoradiation therapy. Therefore, new treatment strategies are needed for NPC. In this study, we investigated the efficacy and molecular mechanisms of TA in NPC treatment.

MATERIALS AND METHODS

TA-induced cell death was detected by cell viability assay in the NPC cell lines, HNE1 and HONE1. Wound healing assay, invasion assay, and Western blot analysis were used to evaluate the antitumor effects of TA in NPC cell lines.

RESULTS

Treatment with TA suppressed the migration and invasion of HNE1 and HONE1 cells. Hepatocyte growth factor enhanced the proliferation, migration, and invasion abilities of NPC cells. This enhancement was successfully inhibited by TA treatment. Treatment with TA increased phosphorylation of p38, and the inhibition of p38 with SB203580 reversed the cytotoxic, anti-invasive, and anti-migratory effects of TA treatment in NPC cell lines. Moreover, inhibition of p38 also reversed the decrease in expression of Slug that was induced by TA treatment.

CONCLUSION

In conclusion, the activation of p38 plays a role in mediating TA-induced cytotoxicity and inhibition of invasion and migration via down-regulation of Slug.

Ionizing radiation promotes advanced malignant traits in nasopharyngeal carcinoma via activation of epithelial-mesenchymal transition and the cancer stem cell phenotype

Post-irradiation residual mass and recurrence always suggest a worse prognosis for nasopharyngeal carcinoma (NPC). Our study aimed to investigate the malignant behaviors of post-irradiation residual NPC cells, to identify the potential underlying mechanisms and to search for appropriate bio-targets to overcome this malignancy. Two NPC cell lines were firstly exposed to 60 Gy irradiation, and residual cells were collected. In our previous study, colony formation assay detected the radioresistance of these cells. Here, the CCK-8 assay examined the cell sensitivity to paclitaxel and cisplatin. Wound-healing and Transwell assays were performed to investigate cell motility and invasion capabilities. Inverted phase-contrast microscopy was used to observe and photograph the morphology of cells. Expression levels of epithelial-mesenchymal transition (EMT)-related proteins were detected by western blot assay in NPC cells and tissues. The mRNA levels of cancer stem cell (CSC)-related genes were detected via qRT-PCR. The results revealed that residual NPC cells exhibited enhanced radioresistance and cross-resistance to paclitaxel and cisplatin. Higher capacities of invasion and migration were also observed. An elongated morphology with pseudopodia formation and broadening in the intercellular space was observed in the residual cells. Downregulation of E-cadherin and upregulation of vimentin were detected in the residual NPC cells and tissues. CSC-related Lgr5 and c-myc were significantly upregulated in the CNE-2-Rs and 6-10B-Rs radioresistance cells. Higher proportions of Lgr5+ cells were observed in radioresistant cells via immunofluorescent staining and flow cytometry. In conclusion, our study demonstrated that residual NPC cells had an advanced malignant transition and presented with both EMT and a CSC phenotype. This provides a possible clue and treatment strategy for advanced and residual NPC.

Outcomes of Saudi Arabian Patients With Nasopharyngeal Cancer Treated With Primarily Neoadjuvant Chemotherapy Followed by Concurrent Chemoradiotherapy

Purpose

Nasopharyngeal cancer (NPC) is the most common head and neck cancer in Saudi Arabia. This study reports the locoregional disease control and survival outcomes in patients with NPC treated in King Abdulaziz University Hospital.

Methods

Patients treated for NPC between June 2007 and October 2014 were retrospectively reviewed. Demographic information, clinicopathologic variables, and chemotherapy data were collected and analyzed. Cumulative survival and disease control rates were calculated by Kaplan-Meier product-limit actuarial method.

Results

Thirty-nine patients with NPC were reviewed. Thirty-five (90%) patients received definitive radiotherapy (RT) and four (10%) had palliative RT. Mean prescribed dose for definitive RT was 68 Gy (range, 60 to 70.2 Gy), delivered with mean doses per fraction of 1.9 Gy (range, 1.8 to 2.1 Gy). After a median follow-up of 15 months (range, 1 to 84 months), 22 (63%) patients who underwent definitive RT were disease free and 13 (37%) were still with disease. During this period, seven (18%) patients died of the disease; five (13%) of them received definitive RT. After 2 years’ follow-up, the actuarial estimate rates were: 85.7% for local control, 91.4% for nodal control, and 85.7% for distant control.

Conclusion

Our study showed a disease with clinical behavior similar to what has been observed in East and Southeast Asia. Further it explored the neoadjuvant chemotherapy approach in treating NPC with results that are comparable to literature. However, little is known about the molecular pathogenesis of this disease in this region, and further research integrating clinical and molecular biomarkers is required.

Advances and challenges in intensity-modulated radiotherapy for nasopharyngeal carcinoma

Nasopharyngeal carcinoma is an endemic disease within specific regions in the world. Radiotherapy is the main treatment. In recent decades, intensity-modulated radiation therapy has undergone a rapid evolution. Compared with two-dimensional radiotherapy and/or three-dimensional conformal radiotherapy, evidence has shown it may improve quality of life and prognosis for patients with nasopharyngeal carcinoma. In addition, helical tomotherapy is an emerging technology of intensity-modulated radiation therapy. Its superiority in dosimetric and clinical outcomes has been demonstrated when compared to traditional intensity-modulated radiation therapy. However, many challenges need to be overcome for intensity-modulated radiation therapy of nasopharyngeal carcinoma in the future. Issues such as the status of concurrent chemotherapy, updating of target delineation, the role of replanning during IMRT, the causes of the main local failure pattern require settlement. The present study reviews traditional intensity-modulated radiation therapy, helical tomotherapy, and new challenges in the management of nasopharyngeal carcinoma.