Endoscopic microwave coagulation therapy for early recurrent T1 nasopharyngeal carcinoma

A novel endoscopic nasopharyngectomy by low-temperature plasma radiofrequency ablation in localized recurrent nasopharyngeal carcinoma

OBJECTIVE

Endoscopic nasopharyngectomy (ENPG) with en bloc resection has been well accepted in resectable localized recurrent nasopharyngeal carcinoma (rNPC), but it is a difficult technique to master for most otorhinolaryngology head and neck surgeons. Ablation surgery is a new and simplified method to remove tumors. We designed a novel method using low-temperature plasma radiofrequency ablation (LPRA) and evaluated the survival benefit.

METHODS

A total of 56 localized rNPC patients were explained in detail and retrospectively analyzed. The surgery method was ablated from the resection margin to the center of the tumor. The postmetastatic overall survival (OS), local relapse-free survival (LRFS) rate, progression-free survival (PFS) and distant metastasis-free survival (DMFS) were analyzed using the Kaplan-Meier method and compared by the log-rank test.

RESULTS

All surgeries were successfully performed without any severe postoperative complications or deaths. The median operation time of ablation and harvested NSFF respectively were 29 min (range, 15-100 min) and 101 min (range, 30-180 min). The average number of hospital days postoperation was 3 days (range, 2-5 days). All cases (100.0%) had radical ablation with negative resection margins. The nasopharyngeal defects were completely re-epithelialized in 54 (96.4%) patients. As of the data cutoff (September 3, 2023), the median follow-up time was 44.3 months (range, 17.1-52.7 months, 95% CI: 40.4-48.2). The 3-year OS, LRFS, PFS and DMFS of the entire cohort were 92.9% (95% CI: 0.862-0.996), 89.3% (95% CI: 0.813-0.973), 87.5% (95% CI: 0.789-0.961), and 92.9% (95% CI: 0.862-0.996), respectively. Cycles of radiotherapy were independent risk factors for OS (p = 0.003; HR, 32.041; 95% CI: 3.365-305.064), LRFS (p = 0.002; HR, 10.762; 95% CI: 2.440-47.459), PFS (p = 0.004; HR, 7.457; 95% CI: 1.925-28.877), and DMFS (p = 0.002; HR, 34.776; 95% CI: 3.806-317.799).

CONCLUSION

Radical endoscopic nasopharyngectomy by using low-temperature plasma radiofrequency ablation is a novel, safe and simplified method to master and disseminate for treating resectable rNPC. However, further data and longer follow-up time are needed to prove its efficacy.

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.

Types of Transnasal Endoscopic Nasopharyngectomy for Recurrent Nasopharyngeal Carcinoma: Shanghai EENT Hospital Experience

Background

Transnasal endoscopic nasopharyngectomy (TEN) has become increasingly used for recurrent nasopharyngeal carcinoma (rNPC); however, there is no report on the definitive resectable contour for TEN according to the latest staging system for nasopharyngeal carcinoma. The aim of this study was to establish the types of TEN for rNPC.

Materials and Methods

A total of 101 rNPC patients underwent TEN from January 2016 to April 2019 at the authors’ institution. TEN was categorized into four types, which included type I (n=40) with resection of the nasopharynx and sinuses; type II (n=10) with lateral extension to the parapharyngeal space; type III (n=40) with lateral extension to the floor of the middle cranial fossa and the infratemporal fossa and superior extension to the orbital apex and the cavernous sinus back to the prevertebral region; and type IV (n=11) with the resection of the involved internal carotid artery following type III. The 2-year overall survival rate (OS) and local recurrence-free survival rate (LRFS) were assessed.

Results

The median time of follow-up was 20 months. Twenty-five patients reoccurred. Nineteen patients died. Independent predictors of outcome on multivariate analysis were recurrent T stage (P = 0.039), types of TEN (P = 0.002) and surgical margin (P = 0.003). The 2-year OS and LRFS was 76.2% and 53.6%, respectively.

Conclusions

The result of TEN in the treatment of rNPC is promising. The types of TEN will provide effective guideline for surgical treatment of rNPC.

Impact of 2.45 GHz Microwave Irradiation on the Fruit Fly, Drosophila melanogaster

Simple Summary

The physiological and behavioral influences of 2.45 GHz microwaves on Drosophila melanogaster were examined. This study indicated that there was no concern regarding the thermal effects of microwave irradiation for levels of daily usage if it is traveling waves. However, it still gave non-thermal effects. We detected genotoxicity and behavioral alterations associated with travelling wave irradiation. Electron spin resonance (ESR) revealed that fruit flies possessed paramagnetic substances in the body such as Fe³⁺, Cu²⁺, Mn²⁺, and organic radicals, and the behavioral tests supported the microwave susceptibility of the insects.

Abstract

The physiological and behavioral influences of 2.45 GHz microwaves on Drosophila melanogaster were examined. Standing waves transitioned into heat energy effectively when passing through the insect body. On the contrary, travelling waves did not transit into heat energy in the insect body. This indicated that there was no concern regarding the thermal effects of microwave irradiation for levels of daily usage. However, we detected genotoxicity and behavioral alterations associated with travelling wave irradiation, which can be attributed to the non-thermal effects of the waves. Electron spin resonance (ESR) revealed that fruit flies possessed paramagnetic substances in the body such as Fe³⁺, Cu²⁺, Mn²⁺, and organic radicals. The temperature dependent intensities of these paramagnetic substances indicated that females possessed more of the components susceptible to electromagnetic waves than males, and the behavioral tests supported the differences between the sexes.

Comparing endoscopic surgeries with open surgeries in terms of effectiveness and safety in salvaging residual or recurrent nasopharyngeal cancer: Systematic review and meta-analysis

Consensus has yet to be reached on the optimal operation for patients with residual or recurrent nasopharyngeal carcinoma (NPC). To compare effectiveness and safety of open surgery and endoscopic surgery for patients with residual or recurrent NPC. Pubmed, Embase, and Cochrane were searched for relevant publications from January 1, 2000 to May 1, 2017. Included studies reported specific residual or local recurrent nasopharyngeal cancer survival data. Proportional meta-analysis was performed on both outcomes with a random-effects model, and the 95% confidential intervals were calculated by Stata 12.0 software. For patients with different tumor classification, a downward trend of 2-year overall survival (OS) was observed for both surgical populations. Endoscopic surgeries achieved bigger rates than open surgeries in patients with recurrent tumor (rT) 1, rT2, and rT3 (93% vs 87%, 77% vs 63%, 67% vs 53%). As for patients with rT4, 2-year OS was similar (35% vs 35%).In addition, the former is less severe complications, lower local recurrence rates (27% vs 32%). Our study found that, compared to open surgery, endoscopic surgery was a safer and more effective treatment modality in managing patients with recurrent or residual NPC.

Outcomes of recurrent nasopharyngeal carcinoma patients treated with endoscopic nasopharyngectomy: a meta-analysis

BACKGROUND

Recurrent nasopharyngeal carcinoma (rNPC) is mainly managed with re-irradiation or salvage surgery. Endoscopic resection is generally considered as the preferred surgical treatment, whereas a standard treatment modality has yet to be established. This article is aimed to summarize the treatment outcomes of endoscopic rNPC resection.

METHODS

Major medical databases including PubMed, EMBASE, Cochrane Central Library, Web of Science, and 2 major Chinese databases, CNKI and Wanfang, were searched for studies on endoscopic rNPC resection. Main characteristics of study and outcomes of interest were retrieved from articles meeting the selection criteria for meta-analysis.

RESULTS

A total of 761 articles were identified through the initial systematic research. The combined 1-year, 2-year, and 5-year overall survival (OS) rates were 97%, 92%, and 73% with random effect model, respectively. The combined 2-year and 5-year disease-free survival (DFS) rates were 81% and 62%, respectively. Meta-regression analysis showed that high recurrent tumor (rT) stage (rT3 to rT4) case proportion was a correlative factor of heterogeneity. Combined 2-year OS rate in rT1, rT2, rT3, and rT4 patients were 100%, 87%, 78%, and 38%, respectively. Combined 2-year DFS rate in rT1 and rT2 patients were and 96% and 86%, respectively.

CONCLUSION

The combined OS and DFS rates of rNPC patients treated with endoscopic nasopharyngectomy were summarized and reported in our study. This meta-analysis indicated that endoscopic nasopharyngectomy has comparable and possibly better treatment outcomes than intensity-modulated radiotherapy (IMRT). Therefore, the result of our study indicated that randomized controlled trials (RCTs) are needed in rNPC patients to compare treatment outcomes of endoscopic nasopharyngectomy vs IMRT.

Nutlin-3, A p53-Mdm2 Antagonist for Nasopharyngeal Carcinoma Treatment

Nasopharyngeal carcinoma (NPC) is a form of head and neck cancer of multifactorial etiolo-gies that is highly prevalent among men in the population of Southern China and Southeast Asia. NPC has claimed many thousands of lives worldwide; but the low awareness of NPC remains a hindrance in early diagnosis and prevention of the disease. NPC is highly responsive to radiotherapy and chemothera-py, but radiocurable NPC is still dependent on concurrent treatment of megavoltage radiotherapy with chemotherapy. Despite a significant reduction in loco-regional and distant metastases, radiotherapy alone has failed to provide a significant improvement in the overall survival rate of NPC, compared to chemo-therapy. In addition, chemo-resistance persists as the major challenge in the management of metastatic NPC although the survival rate of advanced metastatic NPC has significantly improved with the admin-istration of chemotherapy adjunctive to radiotherapy. In this regard, targeted molecular therapy could be explored for the discovery of alternative NPC therapies. Nutlin-3, a small molecule inhibitor that specifi-cally targets p53-Mdm2 interaction offers new therapeutic opportunities by enhancing cancer cell growth arrest and apoptosis through the restoration of the p53-mediated tumor suppression pathway while pro-ducing minimal cytotoxicity and side effects. This review discusses the potential use of Nutlin-3 as a p53-activating drug and the future directions of its clinical research for NPC treatment.

Salvage endoscopic nasopharyngectomy for local recurrent or residual nasopharyngeal carcinoma: a 10-year experience

BACKGROUND

Our aim was to review the outcomes of endoscopic nasopharyngectomy performed on a large series of patients with residual or recurrent nasopharyngeal carcinomas and to identify the prognostic factors.

METHODS

Ninety-one patients with residual (10) and recurrent (81) nasopharyngeal carcinomas who underwent endoscopic nasopharyngectomy were enrolled in our study. Clinical information including gender, age, medical history, symptoms, radiographic findings, tumor stage, treatment, recurrence time, postoperative pathological examination, complications, and outcomes at last follow-up visit was collected. The survival curves and multivariate survival analysis were analyzed using the Kaplan-Meier and Cox proportional hazards model.

RESULTS

Our study included 71 men and 20 women with a median age of 51 years. The lesions were staged as follows: rT1, 30; rT2, 13; rT3, 29; and rT4, 19. No serious operative or postoperative complication was observed. The median follow-up period was 23 months (range, 4-109 months). Tumor necrosis was identified in 40 of 91 patients. At the last follow-up, 42 patients were free of disease, 10 were alive with disease, and 39 had died. At 2- and 5-year follow-up, the overall survival rates were 64.8% and 38.3%, respectively; the disease-free survival rates were 57.5% and 30.2%, respectively, for the two periods. Multivariate analysis showed that T classification (P = 0.02) and tumor necrosis (P = 0.024) were independent risk factors.

CONCLUSIONS

Endoscopic nasopharyngectomy is a feasible and effective surgical treatment for recurrent and residual nasopharyngeal carcinomas.

Effects of Normothermic Conditioned Microwave Irradiation on Cultured Cells Using an Irradiation System with Semiconductor Oscillator and Thermo-regulatory Applicator

We investigated the effects of microwave irradiation under normothermic conditions on cultured cells. For this study, we developed an irradiation system constituted with semiconductor microwave oscillator (2.45 GHz) and thermos-regulatory applicator, which could irradiate microwaves at varied output powers to maintain the temperature of cultured cells at 37 °C. Seven out of eight types of cultured cells were killed by microwave irradiation, where four were not affected by thermal treatment at 42.5 °C. Since the dielectric properties such as ε’, ε” and tanδ showed similar values at 2.45 GHz among cell types and media, the degree of microwave energy absorbed by cells might be almost the same among cell types. Thus, the vulnerability of cells to microwave irradiation might be different among cell types. In HL-60 cells, which were the most sensitive to microwave irradiation, the viability decreased as irradiation time and irradiation output increased; accordingly, the decrease in viability was correlated to an increase in total joule. However, when a high or low amount of joules per minute was supplied, the correlation between cellular viability and total joules became relatively weak. It is hypothesized that kinds of cancer cells are efficiently killed by respective specific output of microwave under normothermic cellular conditions.

New surgical staging system for patients with recurrent nasopharyngeal carcinoma based on the AJCC/UICC rTNM classification system

BACKGROUND

Recurrent tumour, node and metastasis (rTNM) stage system does not have an outstanding prognostic value for survival outcome of patients with recurrent nasopharyngeal carcinoma (rNPC) and it cannot aid the clinicians to choose the most suitable treatment for these patients.

METHODS

In total, 894 rNPC patients were consecutively enroled. All recurrent (r) tumour (T) stages (rT) and node (N) stages (rN) were stratified as resectable and unresectable based on the imaging data of the head and neck. These stages were re-subdivided into surgical T stages (sT) and surgical N stages (sN) with similar clinical characteristics and death risks and were re-integrated into a new 'surgical' stage using a Cox proportional hazards model.

RESULTS

The 5-year overall survival (OS) was 72.0%, 55.1%, 21.1% and 10.1% in 'surgical' stages I, II, III and IV, respectively (P<0.001). The 'surgical' stage was a significant independent prognostic factor for OS (hazard ratio [HR] 1.78, P<0.001) and exhibited enhanced prognostic value compared with the rTNM staging system (area under receiver operating characteristics 0.68 versus 0.63, P<0.001). Endoscopic nasopharyngectomy and intensity-modulated radiation therapy were significant independent positive prognostic factors for the OS of patients with primary lesions in 'surgical' stage I/II and 'surgical' stage III, respectively (P<0.05). A combination of aggressive treatments for loco-regional lesions exhibited a beneficial trend for OS of patients with 'surgical' stage IV (P>0.05).

CONCLUSIONS

Compared with the rTNM stage system, the 'surgical' staging system exhibited enhanced prognostic value for rNPC patient survival and could aid clinicians in choosing the most suitable treatment for rNPC patients.

Salvage endoscopic nasopharyngectomy and intensity-modulated radiotherapy versus conventional radiotherapy in treating locally recurrent nasopharyngeal carcinoma

BACKGROUND

Although endoscopic nasopharyngectomy and intensity-modulated radiotherapy (IMRT) have been reported to be useful in treating isolated local recurrent nasopharyngeal carcinoma (NPC), their efficacy needs to be revaluated with comparison to 2D conventional radiotherapy (RT).

METHODS

Four hundred ten patients with recurrent NPC were retrospectively analyzed, among whom the patients underwent IMRT, endoscopic nasopharyngectomy, and 2D conventional RT.

RESULTS

The 5-year overall survival (OS) and distant metastasis-free survival were significantly higher in endoscopic nasopharyngectomy and IMRT groups than in 2D conventional RT group both in the entire series and in the subgroup of patients with recurrent T1 to 2 NPC (p < .05), except in the subgroup of recurrent T3 to 4 stratifications (IMRT vs 2D conventional RT; 28.8% vs 16.8%; p = .351). Furthermore, endoscopic nasopharyngectomy was associated with better OS than IMRT in the recurrent T1 to 2 subgroup (79.2% vs 62.1%; p = .007). Multivariate analysis indicated therapeutic modality was an independent predictor of OS and distant metastasis-free survival (p < .001).

CONCLUSION

Endoscopic nasopharyngectomy and IMRT are associated with an improved OS and distant metastasis-free survival of patients with recurrent NPC compared to 2D conventional RT in early recurrent disease.

Emerging treatment options for nasopharyngeal carcinoma

Nasopharyngeal carcinoma is endemic in Asia and is etiologically associated with Epstein–Barr virus. Radiotherapy is the primary treatment modality. The role of systemic therapy has become more prominent. Based on multiple phase III studies and meta-analyses, concurrent cisplatin-based chemoradiotherapy is the current standard of care for locally advanced disease (American Joint Committee on Cancer manual [7th edition] stages II–IVb). The reported failure-free survival rates from phase II trials are encouraging for induction + concurrent chemoradiotherapy. Data from ongoing phase III trials comparing induction + concurrent chemoradiotherapy with concurrent chemoradiotherapy will validate the results of these phase II studies. Intensity-modulated radiotherapy techniques are recommended if the resources are available. Locoregional control exceeding 90% and reduced xerostomia-related toxicities can now be achieved using intensity-modulated radiotherapy, although distant control remains the most pressing research problem. The promising results of targeted therapy and Epstein–Barr virus-specific immunotherapy from early clinical trials should be validated in phase III clinical trials. New technology, more effective and less toxic chemotherapy regimens, and targeted therapy offer new opportunities for treating nasopharyngeal carcinoma.

Nasopharyngeal carcinoma: salvage of local recurrence

Local control of nasopharyngeal carcinoma has substantially improved with advancing radiotherapy technology and appropriate combination with chemotherapy. However, when local recurrence occurs, this is one of the most difficult challenges. Aggressive treatment is indicated because long term salvage is achievable particularly for early recurrence, but high risk of complications is a serious concern. Treatment options include different methods of surgery and/or re-irradiation with/without chemotherapy. Available information in the literature is grossly inadequate; most reports compose of small series of highly selected patients with heterogeneous characteristics and treatment. No randomized trials have been performed to evaluate the therapeutic ratio of different treatment methods. This article reviews available treatment options, their therapeutic benefits and risks of complications; the objective is to provide information for developing treatment recommendations and suggestions for future improvement.

Recurrent nasopharyngeal carcinoma: surgical salvage vs. additional chemoradiation

PURPOSE OF REVIEW

The primary treatment modality of nasopharyngeal carcinoma (NPC) is radiation or chemoradiation. With the application of conformal radiation and appropriate chemotherapeutic agents, there was marked improvement in the outcome. Despite this, a small number of patients still develop residual or recurrent disease either in the neck or at the primary site. In recent years there are many developments in the disciplines of surgery, radiation and medical oncology which are applicable for the management of residual or recurrent NPC. It is timely to review the applicability and efficacy of the various therapeutic options.

RECENT FINDINGS

The theme of the literature review included the management of these recurrent or residual diseases in the neck or nasopharynx with open or endoscopic or robot-assisted surgical approaches. The application of radiation techniques such as intensity modulated radiotherapy, stereotactic radiation and brachytherapy was also included. The use of chemotherapy and targeted agents is also reviewed.

SUMMARY

In general, the size, extent and location of the residual or recurrent NPC together with the biological behaviour of the tumour determine the optimal therapy. The surgical and clinical oncological expertise applied optimally will give the best outcome.