Reirradiation with intensity-modulated radiotherapy for locally recurrent T3 to T4 nasopharyngeal carcinoma

Failure patterns and individualized treatment plans of reirradiation for inoperable locally recurrent nasopharyngeal carcinoma

Re-irradiation with intensity-modulated radiotherapy (IMRT) remains the primary treatment modality for inoperable locally recurrent nasopharyngeal carcinoma (NPC). However, the rate of radiation-related late adverse effects is often substantially high. Therefore, we aimed to explore failure patterns and individualized treatment plans of re-irradiation for inoperable locally recurrent NPC. Ninety-seven patients who underwent IMRT were retrospectively analyzed. Sixty-two patients had clinical target volume of recurrence (rCTV) delineated, and thirty-five patients had only gross tumor volume of recurrence (rGTV) delineated. Twenty-nine patients developed second local failures after re-irradiation with IMRT (28 cases available). Among those patients, 64.3% (18/28) of patients and 35.7% (10/28) developed in-field or out-field, respectively. No statistical correlation was observed between target volume (rGTV or rCTV) and the local recurrence rate, local failure patterns, grade ≥ 3 toxicity, and survival. Multivariate analysis showed that recurrent T (rT) stage (HR 2.62, P = 0.019) and rGTV volume (HR 1.73, P = 0.037) were independent prognostic factors for overall survival (OS). Risk stratification based on rT stage and rGTV volume revealed that low risk group had a longer 3-year OS rate (66.7% vs. 23.4%), lower total grade ≥ 3 toxicity (P = 0.004), and lower re-radiation associated mortality rates (HR 0.45, P = 0.03) than high risk group. This study demonstrates that the delineation of rCTV may not be beneficial for re-irradiation using IMRT in locally recurrent NPC. Patients with low risk were most suitable for re-irradiation, with maximizing local salvage and minimizing radiation-related toxicities. More precise and individualized plans of re-irradiation are warranted.

Radiation-induced nasopharyngeal ulcers after re-irradiation with intensity-modulated radiotherapy in locoregional recurrent nasopharyngeal carcinoma patients: a dose-volume-outcome analysis

OBJECTIVE

To analyze the interrelation between radiation dose and radiation-induced nasopharyngeal ulcer (RINU) in locoregional recurrent nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiation therapy (IMRT).

METHODS

Clinical data were collected from 363 patients with locoregional recurrent NPC who received re-irradiated with definitive IMRT from 2009 to 2017. Twenty-nine patients were diagnosed with RINU. Univariate and multivariate analyses were used to re-evaluate the first and second radiotherapy plans and to identify predictive dosimetric factors.

RESULTS

All dosimetric parameters were notably associated with the progression to RINU (p < 0.01) using paired samples Wilcoxon signed rank tests. Multivariate analysis showed that EQD2_ [Formula: see text]D80 (dose for 80 percent volume of the unilateral nasopharynx lesion) was an independent prognostic factor for RINU (p = 0.001). The area under the ROC curve for EQD2_ [Formula: see text]D80 was 0.846 (p < 0.001), and the cutoff point of 137.035 Gy could potentially be the dose tolerance of the nasopharyngeal mucosa.

CONCLUSIONS

The sum of equivalent dose in 2 Gy fractions (EQD2) in the overlapping volumes between initial and re-irradiated nasopharyngeal mucosal tissue can be effective in predicting the hazard of developing RINU in NPC patients undergoing radical re‑irradiation with IMRT and we propose a EQD2_ [Formula: see text]D80 threshold of 137.035 Gy for the nasopharynx.

Induction chemotherapy plus re-irradiation versus re-irradiation alone in locally recurrent nasopharyngeal carcinoma: A model-based analysis

OBJECTIVE

To investigate the role of additional induction chemotherapy (IC) prior to re-irradiation in locally recurrent nasopharyngeal carcinoma (lrNPC).

METHODS

A total of 480 patients from three cancer treatment centers who received re-irradiation between 2012 and 2020 were retrospectively analyzed. Overall survival (OS) was determined using the Kaplan-Meier method and compared with log-rank method. Inverse probability of treatment weighting (IPTW) was performed to match the patients in pairwise treatment groups. Multivariate analysis using the Cox proportional hazards regression method identified predictors of OS. The risk stratification model was defined by the risk score calculated with the sum of coefficients.

RESULTS

In the entire cohort, the addition of IC was associated with similar OS compared with radiotherapy alone (P = 0.58) or with concomitant chemoradiation (P = 0.76). A risk stratification model was constructed and validated based on significant prognostic factors (coefficient) including male (0.6), age ≥ 60 years (0.9), volume of recurrence gross tumor volume ≥ 16 cc (0.7), and lactate dehydrogenase (LDH)-ratio ≥ 0.5 (0.4). In the intermediate-risk group (sum of coefficient: 0.9---1.6), patients with IC plus re-irradiation had a significantly better OS than those who received re-irradiation (P = 0.03). After adjustments for several potentially confounding variables with IPTW, survival benefit of IC was also observed (P = 0.031). However, no significant difference in OS for the additional IC prior to re-irradiation was demonstrated in the low- (sum of coefficient: <0.9) and high-risk group (sum of coefficient: > 1.6).

CONCLUSION

Additional IC prior to re-irradiation was associated with improved OS in the intermediate-risk group of lrNPC, whereas there was no difference for the low-risk and high-risk group. Prospective validation is required to validate these findings.

Advancements of radiotherapy for recurrent head and neck cancer in modern era

Head and neck cancer is a kind of cancer which can be eradicated from radical radiation therapy. However, with best efforts, nearly 40% patients will experience locoregional recurrence. Locoregional recurrence is the main cause of cancer-related death in head and neck cancers, so local treatments play a key role in improving progression free survival. In the last decades, radiation techniques have been tremendously developed, highly conformal radiation techniques such as intensity-modulated radiotherapy, stereotactic body radiation therapy, brachytherapy and proton or heavy ion radiation therapy have their unique radiobiological advances. Although reirradiation is widely used in clinical practice, but little is known when comparing the different techniques. In this review, we will provide a comprehensive overview of the role of reirradiation in recurrent head and neck cancers including radiation techniques, patient selection, overall clinical benefits, and toxicities.

Predictors of toxicity after curative reirradiation with intensity modulated radiotherapy or proton therapy for recurrent head and neck carcinoma: new dose constraints for pharyngeal constrictors muscles and oral cavity

BACKGROUND

Our study aims to identify predictive factors of moderate to severe (grade ≥ 2) late toxicity after reirradiation (reRT) of recurrent head and neck carcinoma (HNC) and explore the correlations between dose organs at risk (OAR) and grade ≥ 2 toxicity.

MATERIAL AND METHODS

Between 09/2007 and 09/2019, 55 patients were re-irradiated with IMRT or proton therapy with curative intent for advanced HNC. Our study included all patients for whom data from the first and second irradiations were available. Co-variables, including interval to reRT, size of re-irradiated PTV, and dose to OAR, were analyzed as potential predictors for developing moderate to severe long-term toxicity with death as a competing risk. Receiver-operator characteristics (ROC) analysis assessed the association between dose/volume parameters and the risk of toxicity.

RESULTS

Twenty-three patients participated in our study. After a median follow-up of 41 months, 65% of the patients experienced grade ≥ 2 late toxicity. The average dose to pharyngeal constrictor muscles (PCM) at the time of reRT showed an association with the risk of grade ≥ 2 dysphagia: AUC = 0.78 (95% CI: 0.53-1), optimal cut-off value = 36.7 Gy (sensitivity 62%/specificity 100%). The average dose to the oral cavity at the time of reRT showed an association with the risk of grade ≥ 2 dysgeusia: AUC = 0.96 (0.89-1), optimal cut-off value = 20.5 Gy (sensitivity 100%/specificity 88%).

CONCLUSION

Our analysis depicted an association between the dose to OAR and the risk of developing moderate to severe dysphagia and dysgeusia and proposed new dose constraints for PCM (36.7 Gy) and oral cavity (20.5 Gy).

An Overview of Head and Neck Tumor Reirradiation: What Has Been Achieved So Far?

The recurrence rate of head and neck cancers (HNCs) after initial treatment may reach 70%, and poor prognosis is reported in most cases. Curative options for recurrent HNCs mainly depend on the treatment history and the recurrent tumor localization. Reirradiation for HNCs is effective and has been included in most guidelines. However, the option remains clinically challenging due to high incidence of severe toxicity, especially in cases of quick infield recurrence. Recent technical advances in radiation therapy (RT) provide the means for upgrade in reirradiation protocols. While the majority of hospitals stay focused on conventional and widely accessible modulated RTs, the particle therapy options emerge as tolerable and providing further treatment opportunities for recurrent HNCs. Still, the progress is impeded by high heterogeneity of the data and the lack of large-scale prospective studies. This review aimed to summarize the outcomes of reirradiation for HNCs in the clinical perspective.

Dosimetric and clinical aspects of head and neck cancer reirradiation with intensity modulated radiotherapy techniques over the last decade

PURPOSE

Tumor recurrence in head and neck cancer (HNC) is very common, given that locoregional disease relapse occurs in up to 50% of patients. The clinical approach towards cancer recurrence is either by surgery and/or chemo-radiotherapy. Irrespective of the treatment, the management of HNC recurrence is highly challenging and often administered with palliative intent only. The aim of this work was to analyze clinical and dosimetric aspects, such as dose prescription, organ at risk sparing, overall survival and locoregional control of HNC after reirradiation with intensity modulated radiotherapy techniques based on studies published over the last decade, due to the wide clinical implementation of the intensity modulated radiotherapy and particularly of volumetric modulated arc therapy (VMAT) for this malignancy.

METHODS

A systematic search of the literature was conducted within Pub-med/Medline databases to find relevant studies. Of the 130 articles fulfilling the initial search criteria, 15 were selected for final analysis that encompassed all set requirements.

RESULTS

Clinical studies revealed the multitude of factors influencing treatment outcome, including anatomical location, histological tumor type, patient-related factors (smoking / comorbidities), cumulative dose and fractionation schedule, reirradiated volume and time between the irradiation of primary and recurrent tumor.

CONCLUSIONS

Since the literature reports no specific data related to the type of intensity modulation used in reirradiation or any correlation with treatment outcome, IMRT and VMAT might offer comparable result after HNC reirradiation. Patient selection is potentially the main factor leading to an efficient outcome.

Robotic stereotactic body radiotherapy for recurrent nasopharyngeal carcinoma

Background

We aimed to evaluate the outcomes of patients reirradiated with stereotactic body radiotherapy for recurrent nasopharyngeal carcinoma (r-NPC) in our hospital.

Methods

We retrospectively analyzed 10 patients with r-NPC previously irradiated with definitive radiotherapy. Local recurrences were irradiated with a dose of 25 to 50 Gy (median: 26.25 Gy) in 3 to 5 fractions (fr) (median: 5 fr). The survival outcomes calculated from the time of recurrence diagnosis were obtained using Kaplan-Meier analysis and compared with the log-rank test. Toxicities were assessed by using Common Terminology Criteria for Adverse Events Version 5.0.

Results

The median age was 55 years (37-79 years), and nine patients were men. The median follow-up was 26 months (3-65 months) after reirradiation. The median overall survival (OS) was 40 months, OS in 1 and 3 years were 80% and 57%, respectively. OS rate of rT4 (n = 5, 50%) was worse compared with rT1, rT2, and rT3 (P = 0.040). In addition, those with less than 24 months of interval between first treatment and recurrence had worse OS (P = 0.017). One patient exhibited Grade 3 toxicity. There is no other Grade ≥3 acute or late toxicities.

Conclusion

In r-NPC, reirradiation is inevitable for patients who are not suitable for radical surgical resection. However, serious complications and side effects prevent dose escalation due to the critical structures previously irradiated. Prospective studies with a large number of patients are required to find the optimal acceptable dose.

Prioritizing sufficient dose to gross tumor volume over normal tissue sparing in intensity-modulated radiotherapy treatment of T4 nasopharyngeal carcinoma

BACKGROUND

In intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma (NPC), priority is often given minimize dose to the critical organs at risk (OARs) to avoid potential morbid sequelae. However, in T4 NPC, dosimetric inadequacy enforced by dose constraints on OARs may significantly impact tumor control.

METHODS

This was a single-institute cohort that patients diagnosed between July 2005 and December 2010 with T4 NPC treated with IMRT. All patients were re-classification according to the 7th-AJCC stage.

RESULTS

Overall, the average doses such as Dmax , D1% , D2% and D1cc for various Central nervous system (CNS) OARs including brainstem, optic nerve, chiasm, temporal lobes and spinal cord were found to exceed published guidelines as RTOG0225. However, no clinical toxicities were seen during the follow-up period except for 13% patients with temporal lobe necrosis.

CONCLUSION

Our retrospective review showed that its feasible to maximize gross tumor volume dose coverage while exceeding most CNS OAR constraint standards, with ideal local control and no obvious increase of craniocerebral toxicity.

Prediction of outcomes in patients with local recurrent nasopharyngeal carcinoma: development and validation of a four-factor prognostic model integrating baseline characteristics and [18F]FDG PET/CT parameters

OBJECTIVES

To investigate the prognostic value of [¹⁸F]FDG PET/CT parameters in local recurrent nasopharyngeal carcinoma (lrNPC) and establish a prognostic tool for lrNPC patients based on these [¹⁸F]FDG PET/CT parameters.

METHODS

A total of 358 lrNPC patients seen from 2010 to 2019 at Sun Yat-sen University Cancer Center with complete baseline characteristics and [¹⁸F]FDG PET/CT data were retrospectively analyzed. Maximal standardized uptake value (SUVmax), SUVmean, SUVpeak, metabolic tumor volume (MTV), total lesion glycolysis (TLG), and heterogeneity index (HI) for recurrent nasopharynx tumors were included. Cox regression analysis was performed to select candidate variables. Subsequently, a nomogram for predicting overall survival (OS) for lrNPC patients was developed and internally validated.

RESULTS

Multivariate Cox analysis results suggested that age ≥ 47 years (hazard ratio (HR), 1.62 (1.18-2.24); p = 0.003)，with smoking history (HR, 1.41 (1.01-1.98); p = 0.046), recurrent T stage {[rT3 vs rT1/2: HR, 1.81 (1.04-3.12); p = 0.037]; [rT4 vs rT1/2: HR, 2.46 (1.32-4.60); p = 0.005]}, and TLG {[37.1-184.3 vs ≤ 37.1: HR, 2.26 (1.49-3.42); p < 0.001]; [>184.3 vs ≤ 37.1: HR, 4.31 (2.50-7.43); p < 0.001]) were independent predictors of OS. A 4-factor nomogram was generated to stratify patients into 3 risk groups. This novel model showed good discrimination with a high C-index (0.752, 95%CI: 0.714-0.790). In addition, the calibration curves showed good agreement between the predicted probabilities and actual observations and decision curve analysis (DCA) suggested that the nomogram was useful for clinical decision-making.

CONCLUSIONS

Our study confirmed that [¹⁸F]FDG PET/CT parameters were valuable in predicting OS and PFS for lrNPC patients. The 4-factor prognostic model combing baseline patient characteristics with [¹⁸F]FDG PET/CT parameters for lrNPC patients had good discrimination, agreement, and clinical application potential.

KEY POINTS

• [¹⁸F]FDG PET/CT parameters were valuable in predicting OS and PFS for lrNPC patients. • The novel 4-factor nomogram for lrNPC patients had good discrimination, agreement, and potential for clinical application.

Hyperfractionation compared with standard fractionation in intensity-modulated radiotherapy for patients with locally advanced recurrent nasopharyngeal carcinoma: a multicentre, randomised, open-label, phase 3 trial

BACKGROUND

Reirradiation in standard fractionation for locally advanced recurrent nasopharyngeal carcinoma after a previous course of high-dose radiotherapy is often associated with substantial late toxicity, negating its overall benefit. We therefore aimed to investigate the efficacy and safety of hyperfractionation compared with standard fractionation in intensity-modulated radiotherapy.

METHODS

This multicentre, randomised, open-label, phase 3 trial was done in three centres in Guangzhou, China. Eligible patients were aged 18-65 years with histopathologically confirmed undifferentiated or differentiated, non-keratinising, advanced locally recurrent nasopharyngeal carcinoma. Participants were randomly assigned (1:1) to either receive hyperfractionation (65 Gy in 54 fractions, given twice daily with an interfractional time interval of at least 6 h) or standard fractionation (60 Gy in 27 fractions, given once a day). Intensity-modulated radiotherapy was used in both groups. A computer program generated the assignment sequence and randomisation was stratified by treatment centre, recurrent tumour stage (T2-T3 vs T4), and recurrent nodal stage (N0 vs N1-N2), determined at the time of randomisation. The two primary endpoints were the incidence of severe late complications defined as the incidence of grade 3 or worse late radiation-induced complications occurring 3 months after the completion of radiotherapy until the latest follow-up in the safety population, and overall survival defined as the time interval from randomisation to death due to any cause in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT02456506.

FINDINGS

Between July 10, 2015, and Dec 23, 2019, 178 patients were screened for eligibility, 144 of whom were enrolled and randomly assigned to hyperfractionation or standard fractionation (n=72 in each group). 35 (24%) participants were women and 109 (76%) were men. After a median follow-up of 45·0 months (IQR 37·3-53·3), there was a significantly lower incidence of grade 3 or worse late radiation-induced toxicity in the hyperfractionation group (23 [34%] of 68 patients) versus the standard fractionation group (39 [57%] of 68 patients; between-group difference -23% [95% CI -39 to -7]; p=0·023). Patients in the hyperfractionation group had better 3-year overall survival than those in the standard fractionation group (74·6% [95% CI 64·4 to 84·8] vs 55·0% [43·4 to 66·6]; hazard ratio for death 0·54 [95% CI 0·33 to 0·88]; p=0·014). There were fewer grade 5 late complications in the hyperfractionation group (five [7%] nasal haemorrhage) than in the standard fractionation group (16 [24%], including two [3%] nasopharyngeal necrosis, 11 [16%] nasal haemorrhage, and three [4%] temporal lobe necrosis).

INTERPRETATION

Hyperfractionated intensity-modulated radiotherapy could significantly decrease the rate of severe late complications and improve overall survival among patients with locally advanced recurrent nasopharyngeal carcinoma. Our findings suggest that hyperfractionated intensity-modulated radiotherapy could be used as the standard of care for these patients.

FUNDING

Key-Area Research and Development of Guangdong Province, the National Natural Science Foundation of China, the Special Support Program for High-level Talents in Sun Yat-sen University Cancer Center, the Guangzhou Science and Technology Plan Project, and the National Ten Thousand Talents Program Science and Technology Innovation Leading Talents, Sun Yat-Sen University Clinical Research 5010 Program.

Biological target volume based on fluorine-18-fluorode-oxyglucose positron emission tomography/computed tomography imaging: a spurious proposition?

PURPOSE

To assess whether the high metabolic region of fluorine-18-fluorode-oxyglucose (¹⁸F-FDG) in the primary lesion is the crux for recurrence in patients with nasopharyngeal carcinoma (NPC), to assess the feasibility and rationale for use of biological target volume (BTV) based on ¹⁸F-FDG positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT).

METHODS

The retrospective study included 33 patients with NPC who underwent ¹⁸F-FDG-PET/CT at the time of initial diagnosis as well as the time of diagnosis of local recurrence. Paired ¹⁸F-FDG-PET/CT images for primary and recurrent lesion were matched by deformation coregistration method to determine the cross-failure rate between two lesions.

RESULTS

The median volume of the V_pri (primary tumor volume using the SUV thresholds of 2.5), the V_high (the volume of high FDG uptake using the SUV50%max isocontour), and the V_recur (the recurrent tumor volume using the SUV thresholds of 2.5) were 22.85, 5.57, and 9.98 cm³, respectively. The cross-failure rate of V_recur∩high showed that 82.82% (27/33) of local recurrent lesions had < 50% overlap volume with the region of high FDG uptake. The cross-failure rate of V_recur∩pri showed that 96.97% (32/33) of local recurrent lesions had > 20% overlap volume with the primary tumor lesions and the median cross rate was up to 71.74%.

CONCLUSION

¹⁸F-FDG-PET/CT may be a powerful tool for automatic target volume delineation, but it may not be the optimal imaging modality for dose escalation radiotherapy based on applicable isocontour. The combination of other functional imaging could delineate the BTV more accurately.

Efficacy and safety of PLDR-IMRT for the re-irradiation of recurrent NPC: A prospective, single-arm, multicenter trial

Salvage treatment of locoregionally recurrent nasopharyngeal carcinoma (NPC) requires weighing the benefits of re-irradiation against increased risks of toxicity. Here, we evaluated the outcomes of patients treated with intensity-modulated-based pulsed low-dose-rate radiotherapy (PLDR-IMRT) to enhance the curative effect of salvage treatment and reduce RT-related SAEs. A prospective clinical trial was conducted from March 2018 to March 2020 at multiple institutions. NPC patients who experienced relapse after radical therapy were re-irradiated with a median dose of 60 Gy (50.4-70 Gy)/30 f (28-35 f) using PLDR-IMRT. Thirty-six NPC patients who underwent PLDR-IMRT for locoregional recurrence were identified. With a median follow-up of 26.2 months, the objective response rate (ORR) of the entire cohort was 91.6%. The estimated mPFS duration was 28 months (95% CI: 24.9-31.1), and the estimated mLRFS duration was 30.4 months (95% CI: 25.2-35.5). The overall survival (OS) rate for all patients was 80.6%, the progression-free survival (PFS) rate was 75% and the cancer-specific survival (CSS) rate was 88.9% at 1 year. The LRFS and DMFS rates were 88.9% and 91.7%, respectively, at 1 year. A combination of systematic therapies could provide survival benefits to patients who experience NPC relapse (p < 0.05), and a Karnofsky performance status (KPS) score of ≥90 was a favorable factor for local control (p < 0.05). The incidence of acute SAEs (grade 3+) from PLDR was 22.2%, and the incidence of chronic SAEs was 19.4% among all patients. PLDR-IMRT combined with systematic therapy can effectively treat patients with locoregionally recurrent nasopharyngeal carcinoma and causes fewer adverse events than the rates expected with IMRT.

Salvage treatments for locally recurrent nasopharyngeal cancer: Systematic review and meta-analysis

The present study aimed to evaluate the effectiveness and safety of various salvage treatments to treat locally recurrent nasopharyngeal carcinoma (IrNPC). A comprehensive search was conducted to gather relevant research publications on salvage treatment for IrNPC. Specifically, 2-, 3-, and 5-year overall survival were the primary outcome. A total of 89 studies with 101 cohorts were collected. Endoscopic nasopharyngectomy was found to be associated with a significantly improved 5-year OS compared with CRT (p = 0.027) and IMRT (p = 0.016). Moreover, based on recurrence T classification, the 2-, 3-, and 5-year OS were similar across different treatments. Endoscopic nasopharyngectomy was associated with a significant reduction in treatment-related complications (grade ≥ 3) compared with IMRT (p < 0.001) and open nasopharyngectomy (p = 0.028). Endoscopic nasopharyngectomy may provide comparable treatment outcomes to re-irradiation, while offering a better safety profile for selective patients with resectable IrNPC.

Endoscopic surgery is superior to intensity-modulated radiotherapy in the treatment of advanced recurrent nasopharyngeal carcinoma

BACKGROUND

The choice between endoscopic surgery and re-radiotherapy as the main treatment modality in patients with advanced recurrent nasopharyngeal carcinoma (rNPC) remains controversial. Therefore, in this study, we compared the efficacies of endoscopic surgery and intensity-modulated radiotherapy (IMRT) in patients with rNPC.

METHODS

All patients with advanced rNPC (T3 and T4) who underwent salvage treatment were enrolled from January 2009 to December 2020. Overall survival (OS) was analyzed using a log-rank analysis. Univariate and multivariate analyses of OS were performed using a Cox regression model. Common treatment-related complications of endoscopic surgery were compared with those of IMRT.

RESULTS

The numbers of patients with T3 and T4 tumors were 163 (64.2%) and 91 (35.8%), respectively; 192 patients underwent endoscopic surgery, 51 received IMRT, and 11 received three-dimensional conformal radiotherapy (3D-CRT). The 3-year OS of patients treated with endoscopic surgery was 59.3%, which was significantly higher than that of patients treated with IMRT (34.7%, p < 0.001) or 3D-CRT (43.6%, p = 0.012). Multivariate analyses showed that IMRT was an independent risk factor for OS compared with endoscopic surgery (hazard ratio, 2.068; 95% confidence interval, 1.395-3.069, p < 0.001). Complications of aural fullness (p = 0.001), nasopharyngeal necrosis (p = 0.004), nasopharyngeal hemorrhage (p = 0.004), dysphagia (p < 0.001), and cerebral infarction (p = 0.030) were significantly lower in the endoscopic surgery group than in the IMRT group.

CONCLUSION

Endoscopic surgery may be a more promising salvage treatment than IMRT to maximize survival and minimize treatment-related complications in advanced rNPC. These results will be significant in deciding the optimal treatment for patients with advanced rNPC.

Treatment of Recurrent Nasopharyngeal Carcinoma: A Sequential Challenge

Simple Summary

Recurrent nasopharyngeal carcinoma is one of the major causes of death among NPC patients. However, there are no international guidelines for the treatment of patients with recurrent NPC now. In this article, we summarize past publications on clinical research and mechanistic studies related to recurrent NPC, combined with the experience and lessons learned by our institutional multidisciplinary team in the treatment of recurrent NPC. We propose an objective protocol for the treatment of recurrent NPC.

Abstract

Recurrent nasopharyngeal carcinoma (NPC), which occurs in 10–20% of patients with primary NPC after the initial treatment modality of intensity-modulated radiation therapy (IMRT), is one of the major causes of death among NPC patients. Patients with recurrent disease without distant metastases still have a chance to be saved, but re-treatment often carries more serious toxicities or higher risks. For this group of patients, both otolaryngologists and oncologists are committed to developing more appropriate treatment regimens that can prolong patient survival and improve survival therapy. Currently, there are no international guidelines for the treatment of patients with recurrent NPC. In this article, we summarize past publications on clinical research and mechanistic studies related to recurrent NPC, combined with the experience and lessons learned by our institutional multidisciplinary team in the treatment of recurrent NPC. We propose an objective protocol for the treatment of recurrent NPC.

Retreatment of Recurrent or Second Primary Head and Neck Cancer After Prior Radiation: Executive Summary of the American Radium Society® (ARS) Appropriate Use Criteria (AUC): Expert Panel on Radiation Oncology - Head and Neck Cancer

BACKGROUND

Re-treatment of recurrent or second primary head and neck cancers occurring in a previously irradiated field is complex. Few guidelines exist to support practice.

METHODS

We performed an updated literature search of peer-reviewed journals in a systematic fashion. Search terms, key questions, and associated clinical case variants were formed by panel consensus. The literature search informed the committee during a blinded vote on the appropriateness of treatment options via the modified Delphi method.

RESULTS

The final number of citations retained for review was 274. These informed five key questions, which focused on patient selection, adjuvant re-irradiation, definitive re-irradiation, stereotactic body radiation (SBRT), and re-irradiation to treat non-squamous cancer. Results of the consensus voting are presented along with discussion of the most current evidence.

CONCLUSIONS

This provides updated evidence-based recommendations and guidelines for the re-treatment of recurrent or second primary cancer of the head and neck.

Management of Nasopharyngeal Carcinoma in Elderly Patients

Nasopharyngeal cancer (NPC) is one of the most difficult cancers in the head and neck region due to the complex geometry of the tumour and the surrounding critical organs. High-dose radical radiotherapy with or without concurrent platinum-based chemotherapy is the primary treatment modality. Around 10%–15% of NPC patients have their diagnosis at age after 70. The management of NPC in elderly patients is particularly challenging as they encompass a broad range of patient phenotypes and are often prone to treatment-related toxicities. Chronologic age alone is insufficient to decide on the management plan. Comprehensive geriatric assessment with evaluation on patients’ functional status, mental condition, estimated life expectancy, comorbidities, risks and benefits of the treatment, patients’ preference, and family support is essential. In addition, little data from randomized controlled trials are available to guide treatment decisions in elderly patients with NPC. In deciding which treatment strategy would be suitable for an individual elderly patient, we reviewed the literature and reviewed the analysis of primary studies, reviews, and guidelines on management of NPC. This review also summarises the current evidence for NPC management in elderly adults from early to late stage of disease.

Impact of salvage radiotherapy on survival of patients with advanced locally recurrent nasopharyngeal carcinoma: Derivation and validation of a predictive model

BACKGROUND

Salvage radiotherapy (RT) is a potentially curative approach for advanced locally recurrent nasopharyngeal carcinoma (NPC), but it is associated with severe toxicities. We aimed to develop a model to predict which patients would benefit from salvage RT.

METHODS

A total of 809 patients who were diagnosed with advanced locally recurrent NPC and treated with salvage RT or palliative chemotherapy (CT) at a high-volume cancer center were included. Patients were randomly split into a training and validation set and matched using inverse probability of treatment weighting. The primary outcome was overall survival (OS). Candidate variables associated with heterogeneous treatment effects were identified with interaction terms in Cox model and incorporated into Salvage Radiotherapy Outcome Score (SARTOS).

RESULTS

The final model included five interaction terms indicating that female sex, presence of prior RT-induced grade ≥ 3 late toxicities and suboptimal performance status were associated with less benefit from salvage RT. SARTOS from the model significantly predicted treatment effects of salvage RT in matched training (P_interation < 0.001) and validation cohorts (P_interation = 0.027). Of patients in high SARTOS subgroup, salvage RT significantly improved survival versus palliative CT in matched training (3-year OS 67.3% vs. 42.0%, HR 0.51, 95% CI 0.32-0.82, P = 0.005) and validation cohorts (3-year OS 71.8% vs. 22.8%, HR 0.40, 95% CI 0.17-0.97, P = 0.042); in low SARTOS subgroup, salvage RT failed to induce survival benefit.

CONCLUSIONS

We found that the SARTOS model could identify a subgroup of patients who benefit from salvage RT versus palliative CT, which helps personalize treatment recommendations for patients with recurrent NPC.

Toripalimab plus intensity-modulated radiotherapy for recurrent nasopharyngeal carcinoma: an open-label single-arm, phase II trial

Background

Toripalimab is a humanized immunoglobulin G₄ monoclonal antibody against programmed death 1. We aimed to investigate the efficacy and safety of toripalimab in combination with intensity-modulated radiotherapy (IMRT) for recurrent nasopharyngeal carcinoma (rNPC).

Methods

We conducted a single-arm, phase II trial with patients with rNPC who had biopsy-proven disease and were unsuitable for local surgery. Eligible patients received IMRT in combination with toripalimab administered via intravenous infusion of 240 mg once every 3 weeks for a maximum of seven cycles. The primary endpoint was the objective response rate at 3 months post radiotherapy. The secondary endpoints included safety profiles, progression-free survival (PFS).

Results

Between May 2019 and January 2020, a total of 25 patients with rNPC were enrolled (18 men (72.0%) and 7 women (28.0%); median (IQR) age, 49.0 (43.5–52.5) years). With a median (IQR) follow-up duration of 14.6 months (13.1–16.2) months, 19 patients (79.2%) achieved an overall response, and disease control was achieved in 23 (95.8%) patients at 3 months post radiotherapy. The 12-month PFS was 91.8% (95% CI 91.7% to 91.9%). The incidences of acute (grade ≥3) blood triglyceride elevation, creatine kinase elevation, skin reaction, and mucositis were 1 (4.0%), 1 (4.0%), 2 (8.0%), and 1 (4.0%), respectively. The incidences of late severe (grade ≥3) nasopharyngeal wall necrosis, nasal bleeding, and trismus were 28.0%, 12.0%, and 4.0%, respectively.

Conclusions

Toripalimab combined with IMRT was tolerable and showed promising antitumor activity in patients with rNPC.

Trial registration number

NCT03854838.

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.

Preliminary Efficacy Report and Prognosis Analysis of Endoscopic Endonasal Nasopharyngectomy for Recurrent Nasopharyngeal Carcinoma

Background: Compared with radiotherapy, endoscopic endonasal nasopharyngectomy (EEN) is increasingly used to treat recurrent nasopharyngeal carcinoma (NPC) because of its good prognosis and mild complications. This study aims to investigate the efficacy of EEN in the treatment of recurrent NPC and factors affecting prognosis.

Methods: This study included all patients who received EEN for recurrent nasopharyngeal carcinoma from April 2016 to April 2020. All operations were performed in Xiangya Hospital Central South University. The patient's 2-year overall survival (OS) rate, disease-free survival (DFS) rate and significant prognostic factors are reported.

Results: There were 38 (67.9%) males and 28 (32.1%) females, with a median age of 43 (range, 24–69 years).43 (76.8%) of the patients in our study were in advanced rT3-rT4 stage and 32 (74.4%) of the patients in the advanced stage had tumor growth closely related to the internal carotid artery (ICA). During a mean follow up period of 44 month (range 1–65 months) post-surgery. The 2-year OS rate was 48.6%, 2-year DFS rate was 42.6%. The 2-year OS rates of rT1-2 and rT3-4 recurrent NPC were 83.9 and 35.6%, respectively. The 2-year DFS rates of rT1-2 and rT3-4 recurrent NPC 76.2 and 56.3%. The advanced T stage were associated with a poor prognosis in terms of OS and DFS.

Conclusions: Data indicate that T staging may be an independent prognostic factor for OS and DFS. Through proper preoperative evaluation, EEN is an alternative treatment option for advanced recurrent NPC that ensures a certain level of efficacy and is relatively safe with few complications. However, additional studies with long-term follow-up and a larger sample size are required.

Key radioresistance regulation models and marker genes identified by integrated transcriptome analysis in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a malignancy that is endemic to China and Southeast Asia. Radiotherapy is the usual treatment, however, radioresistance remains a major reason for failure. This study aimed to find key radioresistance regulation models and marker genes of NPC and clarify the mechanism of NPC radioresistance by RNA sequencing and bioinformatics analysis of the differences in gene expression profiles between radioresistant and radiosensitive NPC tissues. A total of 21 NPC biopsy specimens with different radiosensitivity were analyzed by RNA sequencing. Differentially expressed genes in RNA sequencing data were identified using R software. The differentially expressed gene data derived from RNA sequencing as well as prior knowledge in the form of pathway databases were integrated to find sub‐networks of related genes. The data of RNA sequencing with the GSE48501 data from the GEO database were combined to further search for more reliable genes associated with radioresistance of NPC. Survival analyses using the Kaplan–Meier method based on the expression of the genes were conducted to facilitate the understanding of the clinical significance of the differentially expressed genes. RT‐qPCR was performed to validate the expression levels of the differentially expressed genes. We identified 1182 differentially expressed genes between radioresistant and radiosensitive NPC tissue samples. Compared to the radiosensitive group, 22 genes were significantly upregulated and 1160 genes were downregulated in the radioresistant group. In addition, 10 major NPC radiation resistance network models were identified through integration analysis with known NPC radiation resistance‐associated genes and mechanisms. Furthermore, we identified three core genes, DOCK4, MCM9, and POPDC3 among 12 common downregulated genes in the two datasets, which were validated by RT‐qPCR. The findings of this study provide new clues for clarifying the mechanism of NPC radioresistance, and further experimental studies of these core genes are warranted.

Outcomes for the treatment of locoregional recurrent nasopharyngeal cancer: A systematic review and pooled analysis

Despite advances in the treatment of primary nasopharyngeal carcinoma, locoregional recurrence (lrNPC) occurs at 10%-50% at 5 years. This review aims to evaluate salvage treatment for locally recurrent nasopharyngeal cancer. A literature search for all original articles published on the treatment of lrNPC from January 1990 to January 2021 was conducted. Pooled analysis was performed using a random effects model and assessed statistical heterogeneity of the combined results with I² index. Overall, 66 studies were included for analysis. A total of 5286 patients treated with intensity-modulated radiation therapy (39%), conformal radiotherapy (31%), open nasopharyngectomy (12%), endoscopic nasopharyngectomy (10%), stereotactic radiosurgery (4%), and brachytherapy (4%) were included. Surgical therapy has similar overall survival outcomes to re-irradiation but with decreased treatment-related morbidity and mortality. Both surgical and re-irradiation for lrNPC have similar long-term survival. Surgical approaches to lrNPC may offer similar survival while avoiding treatment-associated morbidity and mortality.

Comparing the Effectiveness of Endoscopic Surgeries With Intensity-Modulated Radiotherapy for Recurrent rT3 and rT4 Nasopharyngeal Carcinoma: A Meta-Analysis

Background

This meta-analysis aimed to compare the efficacy of intensity-modulated radiotherapy (IMRT) and endoscopic surgery (ES) for high T-stage recurrent nasopharyngeal carcinoma (NPC).

Methods

Relevant studies were retrieved in six databases from 02/28,2011 to 02/28,2021. The 2-year, 3-year, 5-year overall survival (OS) rates and 2-year disease-free survival (DFS) rates were calculated to compare the survival outcomes of the two treatments of IMRT and ES. Combined odds ratios (ORs) and 95% confidence interval (C Is) were measured as effect size on the association between high T-stage and 5-year OS rates.

Results

A total of 23 publications involving 2,578 patients with recurrent NPC were included in this study. Of these, 1611 patients with recurrent rT3-4 NPC were treated with ES and IMRT in 358 and 1,253 patients, respectively. The combined 2-year OS and 5-year OS rates for the two treatments were summarized separately, and the 2-year OS and 5-year OS rate for ES were 64% and 52%, respectively. The 2-year OS and 5-year OS rate for IMRT were 65% and 31%, respectively. The combined 2-year DFS rates of IMRT and ES were 60% and 50%, respectively. Combined ORs and 95% confidence intervals for 5-year survival suggest that ES may improve survival in recurrent NPC with rT3-4. In terms of complications, ES in the treatment of high T-stage recurrent NPC is potentially associated with fewer complications.

Conclusions

The results of our study suggest that ES for rT3-4 may be a better treatment than IMRT, but the conclusion still needs to be sought by designing more studies.

Clinical Outcomes of Salvage Endoscopic Nasopharyngectomy for Patients With Advanced Recurrent Nasopharyngeal Carcinoma

Background

Salvage endoscopic nasopharyngectomy has better survival prognosis and fewer complications in the management of early stage rNPC, compared to re-irradiation. However, the treatment modality of advanced recurrent nasopharyngeal carcinoma (rNPC) remains controversial. Thus, the purpose of this study was to investigate the demographics, clinical outcomes, and prognostic factors associated with salvage endoscopic nasopharyngectomy in advanced rNPC.

Methods

This study conducted a retrospective analysis of advanced rNPC patients who underwent salvage surgery betweenm January 2014 and December 2019. The overall survival (OS) and progression-free survival (PFS) were analyzed. Univariable and multivariable analyses of OS and PFS were performed using the Cox regression model. The predicted values of the parameters were determined by means of the receiver operating characteristic (ROC) curve analysis.

Results

Among the 120 patients included, there were 75 patients with rT3 stage and 45 patients with rT4 stage. With the median follow-up time of 18 months,the 3 -year OS and PFS were 55.2% and 29.4%, respectively. Multivariate analyses showed that the rNPC patients with older age, low BMI (Body Mass Index), rT4 stage, tumor necrosis, and tumor invasion into the ICA was predictive of worse OS, whereas low BMI and rT4 stage were associated with worse PFS. In addition, the rT stage was identified as a better predictor of OS (area under the ROC curve: 0.669; P=0.003) than the other clinical features.

Conclusions

Salvage treatment using endoscopic nasopharyngectomy appears to be an effective treatment in the management of patients with advanced rNPC. In addition, case matching studies and prospective studies with larger clinical samples are required to further evaluate the efficacy of endoscopic surgery compared with re-irradiation in advanced rNPC.

International Recommendations on Reirradiation by Intensity Modulated Radiation Therapy for Locally Recurrent Nasopharyngeal Carcinoma

PURPOSE

Reirradiation for locally recurrent nasopharyngeal carcinoma (NPC) is challenging because prior radiation dose delivered in the first course is often close to the tolerance limit of surrounding normal structures. A delicate balance between achieving local salvage and minimizing treatment toxicities is needed. However, high-level evidence is lacking because available reports are mostly retrospective studies on small series of patients. Pragmatic consensus guidelines, based on an extensive literature search and the pooling of opinions by leading specialists, will provide a useful reference to assist decision-making for these difficult decisions.

METHODS AND MATERIALS

A thorough review of available literature on recurrent NPC was conducted. A set of questions and preliminary draft guideline was circulated to a panel of international specialists with extensive experience in this field for voting on controversial areas and comments. A refined second proposal, based on a summary of the initial voting and different opinions expressed, was recirculated to the whole panel for review and reconsideration. The current guideline was based on majority voting after repeated iteration for final agreement.

RESULTS

The initial round of questions showed variations in clinical practice even among the specialists, reflecting the lack of high-quality supporting data and the difficulties in formulating clinical decisions. Through exchange of comments and iterative revisions, recommendations with high-to-moderate agreement were formulated on general treatment strategies and details of reirradiation (including patient selection, targets contouring, dose prescription, and constraints).

CONCLUSION

This paper provides useful reference on radical salvage treatment strategies for recurrent NPC and optimization of reirradiation through review of published evidence and consensus building. However, the final decision by the attending clinician must include full consideration of an individual patient's condition, understanding of the delicate balance between risk and benefits, and acceptance of risk of complications.

Endoscopic Nasopharyngectomy Combined With Internal Carotid Artery Pretreatment for Recurrent Nasopharyngeal Carcinoma

OBJECTIVE

Salvage endoscopic nasopharyngectomy (ENPG) is a reasonable choice for resectable recurrent nasopharyngeal carcinoma (rNPC). However, in past decades, complete removal of the tumor was not feasible when the recurrent lesion was adjacent to the internal carotid artery (ICA). The present article introduces innovative strategies to ensure sufficient surgical margins while avoiding accidental injury to the ICA.

STUDY DESIGN

Retrospective study.

SETTING

Tertiary care center.

METHODS

We retrospectively reviewed rT2-3 rNPC patients with tumor lesions adjacent to the ICA (<5 mm) who underwent ENPG at the Sun Yat-sen University Cancer Center between January 2015 and June 2020. Thirty-seven patients were selected for this study. Seventeen patients underwent ENPG using direct dissection, 10 patients underwent endoscopic-assisted transcervical protection of the parapharyngeal ICA combined with ENPG, and 10 patients underwent ICA embolization followed by ENPG.

RESULTS

With a median follow-up duration of 31 months (range, 5 to 53 months), the 2-year overall survival, progression-free survival, locoregional recurrence-free survival, and distant metastasis-free survival rates of salvage ENPG for rNPC adjacent to the ICA were 88.7%, 72.0%, 72.0%, and 97.3%, respectively. The incidences of grade 1-2 and grade 3-5 postoperative complications were 16.2% and 13.5%, respectively. Two patients experienced ICA rupture during direct dissection but were out of danger after vascular embolization therapy. One patient had a positive margin. Two patients had severe nasopharyngeal wound infections with mucosal flap necrosis.

CONCLUSION

ENPG combined with ICA pretreatment allows the feasible and effective resection of rNPC lesions adjacent to the ICA.

Proton re-irradiation of unresectable recurrent head and neck cancers

Background

This study presents a retrospective analysis (efficacy and toxicity) of outcomes in patients with unresectable recurrence of previously irradiated head and neck (H&N) cancers treated with proton therapy. Locoregional recurrence is the main pattern of failure in the treatment of H&N cancers. Proton re-irradiation in patients with relapse after prior radiotherapy might be valid as promising as a challenging treatment option.

Materials and methods

From November 2015 to January 2020, 30 patients with in-field recurrence of head and neck cancer, who were not suitable for surgery due to medical contraindications, tumor localization, or extent, received re-irradiation with intensity-modulated proton therapy (IMPT). Sites of retreatment included the aerodigestive tract (60%) and the base of skull (40%). The median total dose of prior radiotherapy was 55.0 Gy. The median time to the second course was 38 months. The median re-irradiated tumor volume was 158.1 cm³. Patients were treated with 2.0, 2.4, and 3.0 GyRBE per fraction, with a median equivalent dose (EQD₂) of 57.6 Gy (α/β = 10). Radiation-induced toxicity was recorded according to the RTOG/EORTC criteria.

Results

The 1- and 2-year local control (LC), progression-free survival (PFS), and overall survival (OS) were 52.6/21.0, 21.9/10.9, and 73.4/8.4%, respectively, with a median follow-up time of 21 months. The median overall survival was 16 months. Acute grade 3 toxicity was observed in one patient (3.3%). There were five late severe side effects (16.6%), with one death associated with re-irradiation.

Conclusion

Re-irradiation with a proton beam can be considered a safe and efficient treatment even for a group of patients with unresectable recurrent H&N cancers.

Re-irradiation with Moderate Hypo-Fractionation Using Intensity Modulated Photon or Proton Radiation Therapy in Locally Recurrent Squamous Cell Carcinoma of Nasopharynx

Purpose

This study aimed to analyze the treatment outcomes of locally recurrent nasopharyngeal cancer (NPC) patients following moderate hypo-fractionation re-irradiation (re-RT).

Materials and Methods

Sixty locally recurrent NPC patients underwent hypo-fractionation re-RT. 48.3% had rT3-4, and 30.0% did keratinizing squamous cell carcinoma. Intensity-modulated radiation therapy (IMRT), with or without intensity-modulated proton therapy (IMPT), was used in 66.7% of patients.

Results

With the median follow up of 22 (2~254) months, 31 patients (51.7%) died, 38 (63.3%) developed further treatment failure, and 30 (50.0%) developed ≥Grade 3 toxicity (including seven Grade 5) at time of analysis. The 2- and 5-year rates of overall survival, local failure-free survival, and ≥Grade 3 toxicity-free survival were 57.9% and 45.8%, 64.1% and 52.5%, and 54.8% and 44.9%, respectively. In multivariate analyses, worse factors for OS were iT3-4 (p=0.010) and age at re-RT ≥53 years (p=0.003), those for LFFS were rT3-4 (p=0.022) and rN0-1 (p=0.035), and those for TFS were iT3-4 (p=0.020) and rIMRT/IMPT (p=0.030), respectively. Cumulative dose or fraction size ≥3 Gy at re-RT, however, showed no significance for OS, LFFS and TFS.

Conclusion

Current re-RT with modern RT techniques by moderate hypo-fractionation scheme seemed feasible in treating locally recurrent NPC patients.

Patient-Derived Nasopharyngeal Cancer Organoids for Disease Modeling and Radiation Dose Optimization

Effective radiation treatment (RT) for recurrent nasopharyngeal cancers (NPC), featuring an intrinsic hypoxic sub-volume, remains a clinical challenge. Lack of disease‐specific in-vitro models of NPC, together with difficulties in establishing patient derived xenograft (PDX) models, have further hindered development of personalized therapeutic options. Herein, we established two NPC organoid lines from recurrent NPC PDX models and further characterized and compared these models with original patient tumors using RNA sequencing analysis. Organoids were cultured in hypoxic conditions to examine the effects of hypoxia and radioresistance. These models were then utilized to determine the radiobiological parameters, such as α/β ratio and oxygen enhancement ratio (OER), characteristic to radiosensitive normoxic and radioresistant hypoxic NPC, using simple dose-survival data analytic tools. The results were further validated in-vitro and in-vivo, to determine the optimal boost dose and fractionation regimen required to achieve effective NPC tumor regression. Despite the differences in tumor microenvironment due to the lack of human stroma, RNA sequencing analysis revealed good correlation of NPC PDX and organoid models with patient tumors. Additionally, the established models also mimicked inter-tumoral heterogeneity. Hypoxic NPC organoids were highly radioresistant and had high α/β ratio compared to its normoxic counterparts. In-vitro and in-vivo fractionation studies showed that hypoxic NPC was less sensitive to RT fractionation scheme and required a large bolus dose or 1.4 times of the fractionated dose that was effective against normoxic cells in order to compensate for oxygen deficiency. This study is the first direct experimental evidence to predict optimal RT boost dose required to cause sufficient damage to recurrent hypoxic NPC tumor cells, which can be further used to develop dose-painting algorithms in clinical practice.

Recurrent Nasopharyngeal Cancer: Critical Review of Local Treatment Options Including Recommendations during the COVID-19 Pandemic

Simple Summary

Options for the curative treatment of locally recurrent nasopharyngeal carcinoma include surgery or re-irradiation. Both approaches have been scientifically explored, yet there is no consensus on the indication or definitive preference of the above two salvage treatments. The aim of this review is to summarize the current evidence on the local treatment of recurrent nasopharyngeal carcinoma. The feasibility, safety, and efficacy of salvage surgery and radical re-irradiation are discussed. Recommendations on treatment modifications during the coronavirus disease 2019 pandemic are included as well.

Abstract

Recurrent nasopharyngeal carcinoma represents an extremely challenging therapeutic situation. Given the vulnerability of the already pretreated neurological structures surrounding the nasopharynx, any potential salvage retreatment option bears a significant risk of severe complications that result in high treatment-related morbidity, quality of life deterioration, and even mortality. Yet, with careful patient selection, long-term survival may be achieved after local retreatment in a subgroup of patients with local or regional relapse of nasopharyngeal cancer. Early detection of the recurrence represents the key to therapeutic success, and in the case of early stage disease, several curative treatment options can be offered to the patient, albeit with minimal support in prospective clinical data. In this article, an up-to-date review of published evidence on modern surgical and radiation therapy treatment options is summarized, including currently recommended treatment modifications of both therapeutic approaches during the coronavirus disease 2019 pandemic.

Repeat Radiation for Local Recurrence of Head and Neck Tumors and in Prostate Cancer

BACKGROUND

Recent advances in diagnostic methods and in radiotherapy now increasingly enable repeat radiotherapy with curative intent for the treatment of previously irradiated lesions. In this review, we present data on oncological outcomes and on acute and late sequelae, as far as these are currently known, in patients with head and neck tumors (HNT) or prostate cancer (PCa) who underwent repeat radiotherapy after prior radiotherapy with curative intent.

METHODS

This review is based on clinical series with over 20 patients that were published between May 1998 and April 2018 (HNT) or between October 1998 and October 2018 (PCa) and were retrieved by a search in the PubMed database.

RESULTS

Most of the clinical series retrieved were retrospective and uncontrolled. There were 16 studies that included 2678 patients with recurrent head and neck tumors, and 8 that included 245 patients with recurrent prostate cancer. In patients with squamous cell carcinoma of the head and neck, intensity-modulated radio - therapy (IMRT) and stereotactic body radiotherapy (SBRT) yielded three-year survival rates of 47-57% but also produced substantial acute and late adverse effects. Most of the studies concerning recurrent PCa involved small patient groups. In these studies, repeat radiotherapy with SBRT yielded tumor control rates of 40-80% after 11-24 months of follow-up, with only mild acute toxicity.

CONCLUSION

Although no comparative studies are available, it seems that modern external beam radiotherapy techniques can be used for repeat radiotherapy of locally recurrent head and neck tumors with curative intent after careful patient selection. Repeat radiotherapy of PCa must still be considered experimental, but initial results from small-scale trials are encouraging. The long-term adverse effects cannot yet be accessed. Patients should be selected by an interdisciplinary tumor board. This type of treatment is generally carried out in a specialized center.

The Management of rNPC: Salvage Surgery vs. Re-irradiation

PURPOSE OF REVIEW

Treatment failure, in the form of either persistence or local recurrence, occurs in 10 to 30% of nasopharyngeal carcinoma patients after initial radiotherapy (RT). Early detection of persistent or recurrent disease aids in the recognition of tumors that can be candidates for salvage nasophayngectomy or re-irradiation. There is no consensus till now on the indications or selection of the above two salvage treatment.

RECENT FINDINGS

In recent years, there has been a paradigm shift from open to endoscopic approach for nasopharyngectomy, which carries nearly no complications. For salvage re-irradiation, intensity-modulated radiotherapy (IMRT) is the most commonly indicated modality. Compared to IMRT, salvage endoscopic nasopharyngectomy may be more beneficial in terms of prolonging survival, improving quality of life, and minimizing treatment-related complications and medical costs in a selected subset of recurrent nasopharyngeal carcinoma (rNPC) patients. Salvage nasopharyngectomy should be the mainstay of treatment for rNPC.

Multiple Mechanisms Involving in Radioresistance of Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is the malignant tumor with ethnic and geographical distribution preference. Although intensity-modulated radiotherapy (IMRT)-based radiotherapy combined with chemotherapy and targeted therapy has dramatically improved the overall survival of NPC patients, there are still some patients suffering from recurrent tumors and the prognosis is poor. Multiple mechanisms may be responsible for radioresistance of NPC, such as cancer stem cells (CSCs) existence, gene mutation or aberrant expression of genes, epigenetic modification of genes, abnormal activation of certain signaling pathways, alteration of tumor microenvironment, stress granules (SGs) formation, etc. We conduct a comprehensive review of the published literatures focusing on the causes of radioresistance, retrospect the regulation mechanisms following radiation, and discuss future directions of overcoming the resistance to radiation.

Organs at risk's tolerance and dose limits for head and neck cancer re-irradiation: A literature review

Re-irradiation is becoming an established treatment option for recurrent or second primary head and neck cancer(HNC). However, acute and long-term RT-related toxicities could dramatically impact patients' quality of life. Due to the sparse literature regarding HNC re-irradiation, data on tolerance doses for various organs at risk (OARs) are scarce. Our aim was to systematically review the clinical literature regarding HNC re-irradiation, focusing on treatment toxicity, OARs tolerance, and dose limit recommendations. Thirty-nine studies (three randomized, five prospective, 31 retrospective) including 3766 patients were selected. The median interval time between the first course and re-irradiation was 28  months (range, 6-90). In 1043 (27.6%) patients, postoperative re-irradiation was performed. Re-irradiation doses ranged from 30 Gy in 3 fractions using stereotactic technique to 72 Gy in conventional fractionation using intensity-modulated radiotherapy. Pooled acute and late toxicityrates ≥G3 were 32% and 29.3%, respectively. The most common grade 3-4 toxic effects were radionecrosis, dysphagia requiring feeding tube placement and trismus. In 156 (4.1%) patients, carotid blowout was reported. Recommendations for limiting toxicity included the time interval between radiation treatments, the fractionation schedules, and the re-irradiation treatment volumes. Cumulative dose limit suggestions were found and discussed for the carotid arteries, temporal lobes, and mandible.

Clinical results of proton therapy reirradiation for recurrent nasopharyngeal carcinoma

Background and purpose: Recurrent nasopharyngeal carcinoma (NPC) has limited curative treatment options. Reirradiation is the only potential definitive treatment in advanced stages at a cost of substantial severe and often life-threatening toxicity. Proton therapy (PT) reduces irradiated volume compared with X-ray radiotherapy and could be advantageous in terms of safety and efficacy in a population of heavily pretreated patients. We report the retrospective results of PT reirradiation in recurrent NPC patients treated at our Institution Methods: All recurrent NPC patients treated since the beginning of clinical activity entered the present analysis. Clinical target volume consisted of Gross Tumor volume plus a patient-specific margin depending on disease behavior, tumor location, proximity of organs at risk, previous radiation dose. No elective nodal irradiation was performed. Active scanning technique with the use of Single Field Optimization (SFO) or Multifield Optimization (MFO) was adopted. Cumulative X-ray -PT doses were calculated for all patients using a dose accumulation tool since 2016. Treatment toxicity was retrospectively collected. Results: Between February 2015, and October 2018, 17 recurrent NPC patients were treated. Median follow-up (FUP) was 10 months (range 2-41). Median PT reirradiation dose was 60 Gy RBE (range 30.6-66). The majority of patients (53%) underwent concomitant chemotherapy. Acute toxicity was low with no ≥ G3 adverse events. Late events ≥ G3 occurred in 23.5% of patients. Most frequent late toxicity was hearing impairment (17,6%). G2 soft tissue necrosis occurred in two patients. Fatal bleeding of uncertain cause (either tumor recurrence or G5 carotid blowout) occurred in one patient. Kaplan-Meier 18 months Overall Survival (OS) and Local control (LC) rates were 54.4% and 66.6%, respectively. Conclusions: Our initial results with the use of modern PT for reirradiation of recurrent NPC patients are encouraging. Favorable LC and OS rates were obtained at the cost of acceptable severe late toxicity.

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.

Oncologic outcomes of IMRT versus CRT for nasopharyngeal carcinoma: A meta-analysis

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a prevalent malignancy in Asia particularly southern China. Comparisons of outcomes of conformal radiotherapy (CRT) and intensity-modulated radiotherapy (IMRT) have been still debated. This meta-analysis was carried out to compare oncologic outcomes of CRT and IMRT in the treatment of NPC.

METHODS

A literature search was performed through PubMed, Embase, and the Cochrane library databases from their inceptions to November 10, 2018. Two authors assessed the included studies and extracted data independently. Relative studies that compared oncologic outcomes between CRT and IMRT for NPC were included.

RESULTS

A total of 13 eligible studies were included, which contained 1 RCT, 1 prospective study, and 11 retrospective studies. Our meta-analysis showed that IMRT has increased overall survival (OR = 0.51, 95% CI = 0.41-0.65, P < .00001), locoregional control rate (OR = 0.59, 95% CI = 0.52-0.67, P < .00001), disease-free survival (OR = 0.77, 95% CI = 0.65-0.91, P = .002), and metastasis-free survival (OR = 0.71, 95% CI = 0.54-0.94, P = .01) in comparison with CRT.

CONCLUSION

The results of this meta-analysis indicate IMRT should be a better option for the treatment of NPC because patients who underwent IMRT may benefit from increased overall survival, locoregional control rate, disease-free survival, and metastasis-free survival compared with CRT.

Does East meet West? Towards a unified vision of the management of Nasopharyngeal carcinoma

Nasopharyngeal cancer (NPC) is notable for its wide geographic variation, with incidences as high as 30 in 100,000 in endemic regions but < 1 in 100,000 worldwide. This review aims to identify areas where there could be differences in prognosis, management or outcomes among countries with high or low incidence of NPC. The incidence has generally declined both in endemic and non-endemic regions throughout the years, which may be attributed to the decrease in exposure to risk factors such as early exposure to salted fish and smoking. Ethnicity has an impact both on incidence and prognosis, with Southeast Asians having the highest incidence but also better survival. Concurrent chemoradiotherapy, with or without adjuvant and/or induction chemotherapy, is the standard of care for locoregionally advanced disease, as reflected in clinical practice guidelines. Despite improvements in management, a proportion of patients relapse. Salvage treatment is associated with significant morbidity due to the critical location of the nasopharynx and the toxicities of initial therapy. Clinical expertise is paramount, but is easier to attain in endemic regions and high volume centers where enrollment of patients in clinical trials is more feasible. Collaboration between low and high incidence countries and between low and high volume facilities is key to improving NPC prognosis worldwide.

Long-term survival and late complications of intensity-modulated radiotherapy for recurrent nasopharyngeal carcinoma

BACKGROUND

To evaluate the effectiveness and toxicities of intensity-modulated radiotherapy (IMRT) for locally recurrent nasopharyngeal carcinoma (NPC).

METHODS

One hundred and eighty-four previously irradiated NPC patients with recurrent disease and re-irradiated by IMRT between February 2005 to May 2013 had been reviewed. The disease was re-staged I in 33, II in 27, III in 70 and IV in 54 patients. Seventy-five percent of the patients received cisplatin-based chemotherapy.

RESULTS

The median survival time was 33 months. The 3-year actuarial rates of local recurrence-free survival (LRFS), distant metastases-free survival (DMFS), and overall survival (OS) rates were 85.1, 91.1, and 46.0%, respectively. About 53% of the patients experienced Grade 3-4 late toxicities. Forty-four patients died of massive hemorrhage of the nasopharynx caused by radiation induced mucosal necrosis. Multivariate analysis indicated that chemotherapy and time interval between initial radiotherapy and re-irradiation were independent predictors for DMFS.

CONCLUSION

IMRT is an effective method for patients with locally recurrent NPC. Massive hemorrhage of the nasopharynx is the major sever late complication and also the leading cause of death. Early recurrence is negative factor for DMFS. Combination of chemotherapy can improve DMFS, but not for OS. Optimal salvage treatment strategies focusing on improvement of survival and minimization of late toxicities are warranted.

Establishment of prognostic factors in recurrent nasopharyngeal carcinoma patients who received salvage intensity-modulated radiotherapy: A meta-analysis

Local recurrence remains a major cause of therapeutic failure in patients with nasopharyngeal carcinoma (NPC) and the effective treatment of recurrent NPC (r-NPC) is still a challenge. Intensity-modulated radiotherapy (IMRT) is considered as a favorable technique in the management of r-NPC, especially for extensive lesions. However, local r-NPC is a highly heterogeneous disease and the survival outcome following salvage IMRT varies. Furthermore, due to varied samples and therapeutic protocols, no consensus has been reached in the establishment of prognostic values. Hence, we used Medline and Embase electronic databases to conducted a meta-analysis to generate the best estimation of the prognostic factors in local r-NPC following salvage IMRT. Finally, a total of 783 patients in seven studies were enrolled. Overall, the pooled HR for OS of recurrent T stage and recurrent tumor volume was 1.77 (95% CI = 1.15-2.39) and 2.12 (95% CI = 1.42-2.82), without any heterogeneity. In addition, despite a significant association was observed in the pooled HR of significant compliance for OS, however, significant heterogeneity was also observed (I² = 76.6%, p = 0.039). Furthermore, no significant association was observed among the pooled HRs for OS in terms of age, gender, recurrent time interval, synchronous nodal recurrence, chemotherapy and total re-irradiation dose. Therefore, the present meta-analysis demonstrated that recurrent T stage and tumor volume may serve as the prognostic factors for OS in patients with r-NPC who received salvage IMRT. The other factors such as age, gender, and optimal re-irradiation dose warranted further investigation.

Prospective, Multicenter, Phase 2 Trial of Induction Chemotherapy Followed by Bio-Chemoradiotherapy for Locally Advanced Recurrent Nasopharyngeal Carcinoma

PURPOSE

To evaluate, in a phase 2 study, whether induction docetaxel, cisplatin, and fluorouracil (TPF) followed by weekly docetaxel and cetuximab in concurrence with intensity modulated radiation therapy can improve the treatment outcome for patients with advanced locally recurrent nasopharyngeal carcinoma (rNPC).

METHODS AND MATERIALS

Thirty-three patients with rNPC (T3-T4, N0-N1, M0) were recruited. Of these, 19 patients (57.6%) had stage rT3 recurrence, and the rest had stage rT4. Eight patients also had rN1 at the time of relapse. Treatment outcomes and safety were evaluated.

RESULTS

Among these 33 patients, 1 died after 1 cycle of TPF, 5 patients withdrew from the study during the induction period because of grade ≥3 toxicities; 27 patients completed the whole course of treatment, but 1 died before any assessment could be made. The median follow-up period was 28.5 months. The progression-free survival and overall survival at 3 years for the whole group were 35.7% and 63.8%, respectively. Among the 26 patients who could be assessed after treatment, the complete response rate was 30.8%, and the locoregional control rate at 3 years was 49.2%. Temporal lobe necrosis (TLN) developed in 8 cases. The rates of grade ≥3 hearing loss, soft tissue necrosis, dysphagia, and trismus were 30.8%, 15.4%, 11.5%, and 19.2%, respectively. Overall, 5 patients died owing to acute (1 after cycle 1 TPF and 1 after completion of bio-chemoradiotherapy) or late (2 epistaxis and 1 TLN) treatment-related complications.

CONCLUSIONS

The proposed salvage treatment regimen for advanced locally recurrent NPC could achieve a better treatment outcome than seen in previous studies. However, poor tolerability of induction TPF and the high rate of TLN limit its applicability outside clinical trials.