Nasopharyngectomy for locally advanced recurrent nasopharyngeal carcinoma: Exploring the limits

International Recommendations on Postoperative Management for Potentially Resectable Locally Recurrent Nasopharyngeal Carcinoma

Locally recurrent nasopharyngeal carcinoma (NPC) presents substantial challenges in clinical management. Although postoperative re-irradiation (re-RT) has been acknowledged as a potential treatment option, standardized guidelines and consensus regarding the use of re-RT in this context are lacking. This article provides a comprehensive review and summary of international recommendations on postoperative management for potentially resectable locally recurrent NPC, with a special focus on postoperative re-RT. A thorough search was conducted to identify relevant studies on postoperative re-RT for locally recurrent NPC. Controversial issues, including resectability criteria, margin assessment, indications for postoperative re-RT, and the optimal dose and method of re-RT, were addressed through a Delphi consensus process. The consensus recommendations emphasize the need for a clearer and broader definition of resectability, highlighting the importance of achieving clear surgical margins, preferably through an en bloc approach with frozen section margin assessment. Furthermore, these guidelines suggest considering re-RT for patients with positive or close margins. Optimal postoperative re-RT doses typically range around 60 Gy, and hyperfractionation has shown promise in reducing toxicity. These guidelines aim to assist clinicians in making evidence-based decisions and improving patient outcomes in the management of potentially resectable locally recurrent NPC. By addressing key areas of controversy and providing recommendations on resectability, margin assessment, and re-RT parameters, these guidelines serve as a valuable resource for clinical experts involved in the treatment of locally recurrent NPC.

Extracellular vesicles derived from paclitaxel-sensitive nasopharyngeal carcinoma cells deliver miR-183-5p and impart paclitaxel sensitivity through a mechanism involving P-gp

Paclitaxel treatment has been applied for late-stage nasopharyngeal carcinoma (NPC), but therapy failure usually occurs due to paclitaxel resistance. Besides, microRNAs (miRs) delivered by extracellular vesicles (EVs) have been demonstrated as promising biomarkers affecting cancer development. Our work clarified the role of bioinformatically predicted miR-183-5p, which could be delivered by EVs, in the paclitaxel resistance of NPC. Downstream targets of miR-183-5p were predicted in publicly available databases, followed by GO enrichment analysis. A confirmatory dual-luciferase reporter assay determined the targeting relationship between miR-183-5p and P-glycoprotein (P-gp). The shuttling of extracellular miR-183-5p was identified by immunofluorescence. EVs transferred miR-183-5p from paclitaxel-sensitive NPC cells to paclitaxel-resistant NPC cells. Furthermore, overexpression of miR-183-5p and under-expression of P-gp occurred in clinical samples and cells of NPC. High expression of miR-183-5p corresponded to better survival of paclitaxel-treated patients. The effects of manipulated expression of miR-183-5p on NPC cell activities, tumor growth, and paclitaxel resistance were investigated in vitro and in vivo. Its effect was achieved through negatively regulating drug transporters P-gp. Ectopically expressed miR-183-5p enhanced the cancer-suppressive effects of paclitaxel by targeting P-gp, corresponding to diminished cell viability and tumor growth. Taken together, this work goes to elucidate the mechanical actions of miR-183-5p delivered by EVs and its significant contribution towards paclitaxel sensitivity to NPC. 1. This study provides mechanistic insight into the role of miR-183-5p-containing EVs in NPC. 2. The intercellular transportation of miR-183-5p is mediated by EVs in NPC. 3. Overexpressing miR-183-5p facilitates the anti-tumor effects of paclitaxel in NPC. 4. miR-183-5p suppresses paclitaxel resistance of NPC cells by inhibiting P-gp.

Long-term results of robotic-assisted nasopharyngectomy for recurrent nasopharyngeal carcinoma

BACKGROUND

We have previously reported our early experience in robotic-assisted nasopharyngectomy. The current case series is a report of our experience in 33 robotic-assisted nasopharyngectomy.

METHODS

Prospective series of patients who underwent robotic-assisted nasopharyngectomy for local recurrent nasopharyngeal carcinoma from January 2010 to March 2019.

RESULTS

Thirty-one patients underwent robotic-assisted nasopharyngectomy with two additional second procedure for positive margin. Median age is 55 years (29-85). Twenty-five patients had rT1 disease and six patients had tumor invaded sphenoid floor (rT3). Median operative time was 227 min and median blood loss was 200 ml. The median follow-up period for all patients were 38 months. Four patients had local recurrence. Five-year local control rate, overall survival, and disease-free survival are 85.1%, 55.7%, and 69.1%, respectively.

CONCLUSION

Robotic-assisted nasopharyngectomy for recurrent nasopharyngectomy was showed to have a high local control rate. The operating time was comparable to open surgery.

An Endoscopic Endonasal Nasopharyngectomy with Posterolateral Extension

Background Invasion depth influences the choice for extirpation of nasopharyngeal malignancies. This study aims to validate the feasibility of endoscopic endonasal resection of lesions with a posterolateral invasion. As a secondary goal, the study intends to propose a classification system of endoscopic endonasal nasopharyngectomy determined by the depth of posterolateral invasion.

Methods Eight cadaveric specimens (16 sides) underwent progressive nasopharyngectomy using an endoscopic endonasal approach. Resection of the torus tubarius, Eustachian tube (ET), medial pterygoid plate and muscle, lateral nasal wall, and lateral pterygoid plate and muscle were sequentially performed to expose the fossa of Rosenmüller, petroclival region, parapharyngeal space (PPS), and jugular foramen, respectively.

Results Technical feasibility of endonasal nasopharyngectomy toward a posterolateral direction was validated in all 16 sides. Nasopharyngectomy was classified into four types as follows: (1) type 1: resection restricted to the posterior or superior nasopharynx; (2) type 2: resection includes the torus tubarius which is suitable for lesions extended into the petroclival region; (3) type 3: resection includes the distal cartilaginous ET, medial pterygoid plate, and muscle, often required for lesions extending laterally into the PPS; And (4) type 4: resection includes the lateral nasal wall, pterygoid plates and muscles, and all the cartilaginous ET. This extensive resection is required for lesions involving the carotid artery or extending to the jugular foramen region.

Conclusion Selected lesions with posterolateral invasion into the PPS or jugular foramen is amenable to a resection via expanded endonasal approach. Classification of nasopharyngectomy based on tumor depth of posterolateral invasion helps to plan a surgical approach.

Transinfratemporal Fossa Transposition of the Temporalis Muscle Flap for Skull Base Reconstruction after Endoscopic Expanded Nasopharyngectomy: Anatomical Study and Clinical Application

Objective Temporalis muscle flap (TMF) is widely used in traditional skull base surgery, but its application in endoscopic skull base surgery remains rarely reported. We aimed to investigate the surgical anatomy and clinical application of TMF for reconstruction of skull base defects after expanded endoscopic nasopharyngectomy.

Methods Nine fresh cadaver heads (18 sides) were used for endoscopic dissection at the University of Pittsburgh School of Medicine in the United States. TMF was harvested using a traditional open approach and then transposed into the maxillary sinus and nasal cavity through the infratemporal fossa using an endoscopic transnasal transmaxillary approach. TMF length was then measured. Moreover, TMF was used for the reconstruction of skull base defects of six patients with recurrent nasopharyngeal carcinoma after expanded endoscopic nasopharyngectomy.

Results The length of TMF harvested from the temporal line to the tip of the coronoid process of the mandible was 11.8 ± 0.9 cm. The widest part of the flap was 9.0 ± 0.4 cm. When TMF was dislocated from the coronoid process of the mandible, approximately another 2 cm of reach could be obtained. When the superficial layer of the temporalis muscle was split from the deep layer, the pedicle length could be extended 1.9 ± 0.2 cm. TMF could cover skull base defects in the anterior skull base, sellar, and clivus regions.

Conclusion TMF can be used to reconstruct skull base defects after endoscopic expanded nasopharyngectomy and can effectively prevent the occurrence of serious complications in patients with recurrent nasopharyngeal carcinoma.

Extended endonasal approach versus maxillary swing approach to the parapharyngeal space

BACKGROUND

The nasopharyngeal and parapharyngeal spaces are difficult for surgeons to access. Of the various external routes described, the maxillary swing has emerged as the gold standard because of its simplicity. However, its morbidity has led to the development of less invasive techniques. The purpose of our study was to compare the surgical anatomy of the maxillary swing with that of the endoscopic endonasal approach.

METHODS

Each procedure was performed on 10 anatomic specimens. The exposure and the limits obtained were evaluated. A CT scan analysis was performed.

RESULTS

The endoscopic endonasal approach extended the limits, offering wider exposure. The endoscopic endonasal approach made possible better visualization of deep structures and precise dissection of the parapharyngeal spaces. However, the maxillary swing provided better access to the oropharynx and could be completed 3 times faster.

CONCLUSION

The endoscopic endonasal approach provides excellent exposure, a wide dissection range, and precise definition of anatomic structures, making it an alternative of choice rather than the maxillary swing approach.

Epstein-Barr virus encoded microRNA BART7 regulates radiation sensitivity of nasopharyngeal carcinoma

Epstein-Barr virus (EBV)-associated nasopharyngeal carcinoma (NPC) is very sensitive to radiotherapy. To date, the underlying mechanism remains poorly understood. Here, we demonstrated that expression of EBV-encoded microRNA BART7 (ebv-miR-BART7) increases responsiveness of NPC to radiation treatment by targeting GFPT1/TGFβ1 signaling. GFPT1 is the the key rate-limiting enzyme of the hexosamine signaling pathway and governs TGFβ1 production. TGFβ1, a pleotropic cytokine with the potency to trigger self-renewal and damage-repair machinery in somatic cells. TGFβ1 can protect zebrafish embryo from the lethal effects of radiation treatment. In silico analysis showed that ebv-miR-BART7 could target GFPT1 transcript. Correlation analysis on primary NPC tissues suggested that ebv-miR-BART7 and GFPT1 have negative expression correlation. Expression of GFPT1 and TGFβ1 were inducible by radiation in NPC cell with ebv-miR-BART7 expression. Further, suppressing endogenous GFPT1 expression inhibited TGFβ1 which subsequently increased the responsiveness of NPC to radiation treatment. Taken together, our results demonstrated that ebv-miR-BART7 controls TGFβ1 production by targeting GFPT1. Detection of ebv-miR-BART7 may provide useful indicator for monitoring NPC progression and predict therapeutic outcomes.

BEX3 contributes to cisplatin chemoresistance in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) can develop cisplatin‐resistant phenotype. Research has revealed that enriched in cancer stem cell population is involved in developing cisplatin‐resistant phenotype. CD271 is a candidate stem cell maker in head and neck cancers. The CD receptor does not possess any enzymatic property. Signal transduction function of CD271 is mediated by the cellular receptor‐associated protein. Our data showed that Brain‐expressed X‐linked 3 (BEX3), a CD271 receptor‐associated protein, was overexpressed in NPC. BEX3 overexpression was a unique event in cancer developed in the head and neck regions, especially NPC. BEX3 expression was inducible by cisplatin in NPC. In cisplatin‐resistant NPC xenograft, treatment with nontoxic level of cisplatin led to a remarkable increase in BEX3 level. High BEX3 expression was accompanied with high octamer‐binding transcription factor 4 (OCT4) expression in cisplatin‐resistant NPC. To confirm the inducing role of BEX3 on OCT4 expression, we knockdown BEX3 using siRNA and compared the expression of OCT4 with mock transfectants. Suppressing BEX3 transcripts led to a significant reduction in OCT4. In addition, targeting BEX3 using shRNA could increase the sensitivity of NPC cells to cisplatin. In summary, our results indicated a unique functional role of BEX3 in mediating the sensitivity of NPC cells to cisplatin. Targeting or blocking BEX3 activity might be useful in reversing the cisplatin‐resistant phenotype in NPC.

MicroRNA-138-5p controls sensitivity of nasopharyngeal carcinoma to radiation by targeting EIF4EBP1

Radiation therapy is the standard treatment for primary nasopharyngeal carcinoma (NPC). MicroRNA regulates cancer responsiveness to radiation therapy by controlling the genes involved in radiation responses. Recent studies suggested that downregulation of microRNA-138-5p was clinically significant in NPC. Here, we evaluated the effect of miR-138-5p on radiosensitivity of NPC cells and explored the underlying mechanisms by identifying its target gene that impacted sensitivity to radiation. Our results revealed that overexpression of miR-138-5p reduced the ability to form colonies, inhibited proliferation, and enhanced radiation-induced DNA damage and autophagy in NPC cells upon radiation treatment. By integrating predicted targets with the transcripts downregulated by miR-138-5p, EIF4EBP1 was identified to be a target gene of miR-138-5p. Results from luciferase reporter assay demonstrated that miR-138-5p downregulated the expression of EIF4EBP1 by binding to the 3'-UTR. Silence of EIF4EBP1 enhanced radiosensitivity of NPC cells as evidenced by reduced ability to form colonies after radiation exposure. In summary, our results indicated that miR-138-5p enhanced radiosensitivity of NPC cells by targeting EIF4EBP1. Further studies are warranted to investigate the potential use of miR-138-5p in the clinical management and treatment prediction of NPC patients.

Combined transcervical and orbitozygomatic approach for the removal of a nasopharyngeal adenocarcinoma

OBJECTIVE

In some cases, the exposure and safeguarding of the internal carotid artery (ICA) are not easy by the maxillary swing approach that is used as a mainstay for the removal of nasopharyngeal tumors. To address this issue, we have developed a new combined transcervical and orbitozygomatic approach.

METHODS

A nasopharyngeal adenocarcinoma arose in a 52-year-old patient and occupied the right middle skull base extending to the ICA. We first identified and dissected the ICA from the posterolateral part of the tumor using a transcervical approach. Then, the tumor was approached and removed by an orbitozygomatic technique with hemifacial dismasking. The surgical defect was filled using a temporal muscle flap, which was divided into two parts according to the blood supply from either the anterior or the posterior deep temporal artery.

RESULTS

The postoperative course was uneventful and favorable cosmetic results were obtained. The patient has been free of carcinoma for more than 40 months after the surgery.

CONCLUSION

Our new combined approach might be a good option for selected patients with nasopharyngeal tumors.

Impact of resection margin status on outcome after salvage nasopharyngectomy for recurrent nasopharyngeal carcinoma

BACKGROUND

The purpose of this study was to present the postoperative local tumor control and survival with regard to the different resection margin statuses during salvage nasopharyngectomy.

METHODS

We conducted a whole-organ study of nasopharyngectomy specimens.

RESULTS

Between 2005 and 2010, 126 patients underwent maxillary swing nasopharyngectomy. The T classification of the recurrent tumor was: T1, 23.8%; T2, 41.3%; T3, 28.6%; and T4, 6.3%. The chance of clear, close, and involved resection margins at nasopharyngectomy was 44.4%, 31.0%, and 24.6%, respectively. At follow-up, the corresponding risk of local tumor recurrence after surgery was 10.7%, 38.5%, and 67.7%, respectively. The local tumor control was significantly worse in patients with involved margins compared with those with close margins (p = .01), which was, in turn, significantly worse than those with clear margins (p = .04).

CONCLUSION

The primary objective of salvage nasopharyngectomy is to achieve clear resection margins. Close and involved margins result in significantly inferior local tumor control and overall survival. © 2015 Wiley Periodicals, Inc. Head Neck 38: E594-E599, 2016.

The role of Epstein-Barr virus-encoded microRNA BART7 status of resection margins in the prediction of local recurrence after salvage nasopharyngectomy for recurrent nasopharyngeal carcinoma

BACKGROUND

Local recurrence is the major cause of treatment failure in patients who undergo surgical salvage of recurrent nasopharyngeal carcinoma (NPC) after radiotherapy. The authors investigated the role of Epstein-Barr virus (EBV)-encoded Bam HI-A rightward transcript 7 microRNA (BART7) status in resection margins in the identification of a subgroup of patients who may benefit from adjuvant reradiation after surgery.

METHODS

One hundred two consecutive patients who had histologically clear resection margins after undergoing nasopharyngectomy for recurrent NPC were studied. The status of EBV microRNA BART7 in resection margins was investigated and correlated with the pattern of subsequent disease recurrence.

RESULTS

After a median follow-up of 64 months, 20 patients (19.6%) developed local recurrence after surgery despite histologically uninvolved margins. The risk of local recurrence in patients with histologically close (<5 mm) and clear (≥5 mm) margins was 31.6% and 12.5%, respectively. In patients with clear histologic margins, those with margins that were positive for EBV microRNA BART7 has a significantly higher chance of developing local tumor recurrence (P = .016) than those with negative molecular margins. The difference was not significant when the histologic clearance at the resection margins was <5 mm.

CONCLUSIONS

Tissue EBV microRNA BART7 is useful for identifying a subgroup of patients with histologically clear margins who are at increased risk of subsequent local tumor recurrence. Postoperative adjuvant treatment is warranted for these patients.

Advantages of intensity modulated radiotherapy in recurrent T1-2 nasopharyngeal carcinoma: a retrospective study

Background

Recurrent T1-2 Nasopharyngeal Carcinoma (rT1-2) may be salvaged by 3D – CRT (3D-Conformal Radiotherapy), IMRT (Intensity Modulated Radiotherapy), Brachytherapy (BT), BT with external radiotherapy. The purpose of this study is to address the efficacy and toxicity profile of aforementioned four modalities for rT1-2 NPC.

Methods

168 patients, median age 48 years (range 16–75 years) proven rT1-2 NPC were diagnosed and treated with four different irradiation modalities (3D-CRT, IMRT, BT, BT with external radiotherapy). Median time to recurrence was 30 months (range 1–180 months). The median follow-up time was 28 months (range, 4–135 months).

Results

161 patients completed a median dose of 6445 cGy (ranging 30 to 87 Gy). Seven patients prematurely terminated their treatment due to acute side-effects and received 30–49 Gy. The 1- and 3-year local regional recurrent free survival (LRRFS), distant free survival (DFS), and overall survival (OS) rates were 82.03% vs. 82.03% vs. 82.58%, 51.33% vs. 51.33% vs. 53.41, respectively. Gender and recurrence T-classification were the two significant adverse prognostic factors for LRRFS, DFS, and OS rates. Grade 3 or 4 toxicities were tolerable.

Conclusion

3D-CRT, IMRT, BT, BT with external radiotherapy are feasible and efficacious for rT1-2 NPC. In toxicity 3D-CRT/IMRT group is lower than BT group. IMRT is superior for rT1-2 NPC.

Recurrent nasopharyngeal carcinoma: a clinical dilemma and challenge

Recurrent nasopharyngeal carcinoma, which represents a small proportion of head-and-neck cancers, has a unique set of patho-clinical characteristics. The management of recurrent nasopharyngeal carcinoma remains a challenging clinical problem. Traditional treatments offer limited local control and survival benefits; more seriously, they frequently induce severe late complications. Recently, novel treatment techniques and strategies-including precision radiotherapy, endoscopic surgery or transoral robotic resection, third-generation chemotherapy regimens, and targeted therapies and immunotherapy-have provided new hope for patients with recurrent nasopharyngeal carcinoma. Some of these patients can potentially be cured with modern treatments. However, a lack of adequate evidence makes it difficult for clinicians to apply these powerful techniques and strategies. Individualized management guidelines, full evaluation of quality of life in these patients, and a further understanding of the mechanisms underlying recurrence are future directions for research into recurrent nasopharyngeal carcinoma.

Surgical management of recurrent nasopharyngeal carcinoma

OBJECTIVES

Nasopharyngeal carcinoma is a unique tumour which is endemic in Southern China including Hong Kong. While the treatment results for primary cancer has been encouraging, management of persistent or recurrent tumours has been challenging. Compared to other surgical approaches, the maxillary swing operation provides spacious access to the bilateral nasopharynx and the ipsilateral parapharyngeal space, allowing resection of tumours with wide margins. In this article, we will present our results in the surgical management of recurrent nasopharyngeal carcinoma.

MATERIALS AND METHODS

Retrospective review.

RESULTS

Over the years, we have performed salvage maxillary swing nasopharyngectomy for 312 patients. Microscopic negative resection margins were achieved in the majority (79.5%) of the patients. The overall local recurrence rate after surgery was 13.1%, the risk of which was significantly higher in patients with previous positive resection margins. The overall 5-year actuarial local tumour control and overall survival was 74% and 62%, respectively, which was significantly higher in patients with clear resection. For small tumours located in the posterior wall, minimally invasive approach can be used, which included the endoscopic resection, or more recently, the transoral robotic (TORS) assisted approach.

CONCLUSION

The result of surgical salvage of recurrent nasopharyngeal carcinoma is promising. Every effort should be made to ensure microscopic clearance of disease as well as to minimize the potential complications of surgery that may adversely affect the subsequent quality of life.

Endoscopic Endonasal Nasopharyngectomy in Selected Cancers

Objective

To describe the different surgical techniques for nasopharyngeal endoscopic resection (NER) and to support the efficacy of the endoscopic endonasal approach in the management of selected primary and locally recurrent nasopharyngeal tumors (NPTs).

Study Design

Case series with chart review.

Setting

Patients affected by NPTs who underwent NER from 1997 to 2011 at two Italian referral centers.

Subjects and Methods

NER was tailored to the NPT extension and classified as follows: type 1 NER, resection of the posterior nasopharyngeal wall; type 2 NER, resection superiorly extended to the sphenoid; type 3 NER, trans-pterygoid approach to the postero-lateral nasopharynx with removal of pterygoid plates and Eustachian tube, under control of parapharyngeal-petrous-cavernous segments of the internal carotid artery.

Results

Thirty-six consecutive patients with primary (9 cases) or locally recurrent (27 cases) NPTs were enrolled. The lesions were staged as follows: stage I, 16 (44.4%); stage II, 3 (8.4%); stage III, 15 (41.6%); and stage IVA, 2 (5.6%). Type 1 NER was performed in 6 cases, type 2 NER in 12, type 3 NER in 16, and bilateral-extended type 3 NER in 2. No perioperative mortality or major complications were observed. Postoperatively, 11 patients received intensity-modulated radiotherapy, with or without chemotherapy. Follow-up ranged from 2 to 173 months (mean: 38 months). Five years overall, disease-specific, and disease-free survivals were 75.1% ± 9.13%, 80.9% ± 7.79%, and 58.1% ± 14.8%, respectively.

Conclusion

NER is a feasible and minimally invasive surgical approach for the management of selected primary and locally recurrent NPTs. Our preliminary outcomes are promising, with local control rates comparable to those of conventional procedures. Larger case series and longer follow-up are needed to validate the reproducibility and efficacy of the technique.

Lateral palatal flap approach to the nasopharynx and parapharyngeal space for transoral robotic surgery: a cadaveric study

The da Vinci surgical robot has been used for minimally invasive surgery of the head and neck region including resection of tumors in the nasopharynx. Access to and vision of the nasopharynx with the robot are difficult. A pure transoral approach and midline palatal split approach have been described. The disadvantage of these approaches is the limited lateral access to the parapharyngeal space. The objective of this study was to investigate the feasibility of accessing the nasopharynx and parapharyngeal space with a lateral palatal flap. Two complete nasopharyngectomies with resection of the parapharyngeal space and exposure of the internal carotid artery and branches of the mandibular nerves were performed on two fresh cadavers with the da Vinci surgical robot. The set up of the robot, the surgical procedure of elevating the lateral palatal flap, and robotic resection of the nasopharynx and parapharyngeal space are described.