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

Salvage Endoscopic Nasopharyngectomy for Recurrent Nasopharyngeal Cancer: an Institutional Experience

Objective

This study aims to present the surgical and oncological long-term outcomes of patients with locally recurrent nasopharyngeal cancer (NPC) following endoscopic endonasal nasopharyngectomy (EEN).

Methods

The medical records of 11 patients who underwent EEN due to recurrent NPC were retrospectively reviewed.

Results

The mean age of the patient cohort, consisting of 10 males (90.9%) and one female (9.1%), was 44±13.01 years at the time of initial diagnosis. Seven patients (63.7%) had local recurrence, and four patients (36.3%) had loco-regional recurrence. The mean time to first recurrence from the initial diagnosis was 40.3 months, with a 5-year overall survival (OS) rate of 72.7% and a disease-free survival (DFS) rate of 27.3%. There were no significant differences between the concurrent chemoradiotherapy (CRT) and induction chemotherapy+concurrent CRT treatment groups in terms of DFS and OS as a first-line treatment (p=0.645).

Conclusion

EEN is a viable alternative approach for selected cases of locally recurrent NPC, considering the morbidities associated with re-irradiation.

Current knowledge of antisense long non-coding RNA in the occurrence and prognosis of skull base tumors

Antisense long non-coding RNA (AS-lncRNA) represents a novel class of RNA molecules. In recent years, it has been discovered that AS-lncRNAs play crucial roles in various biological processes, particularly in the onset and progression of tumors. Skull base tumors, originating from the base of the brain, exhibit specific expression patterns of AS-lncRNA which correlate significantly with clinical characteristics. This makes AS-lncRNA a promising candidate as a tumor marker. Functional studies have revealed that AS-lncRNAs can regulate gene expression by acting as miRNA sponges and interacting with RBPs. Consequently, they play pivotal roles in tumor cell cycle, apoptosis, angiogenesis, invasion, and metastasis processes. Further exploration into the mechanisms of AS-lncRNA in tumors holds substantial theoretical significance for deeper insights into the etiology, pathogenesis, and RNA dynamics of skull base tumors. Moreover, AS-lncRNA could serve as molecular markers or potential targets for early diagnosis. Their potential extends to efficacy assessment, prognosis prediction, and gene therapy, suggesting broad clinical applications. In summary, AS-lncRNA emerges as a promising molecular marker implicated in the onset and progression of skull base tumors.

Improvements and challenges of tissue preparation for spatial transcriptome analysis of skull base tumors

BACKGROUND

Spatial transcriptome (ST) provides molecular profiles of tumor cells at the spatial level, which brings new progress to the research of tumors and the tumor microenvironment. This study summarizes the experiences and lessons learned in the spatial section preparation of two different pathological types of nose and skull base tumors at our institution, with the aim of offering guidelines to researchers to avoid wasting precious samples and provide a basis for the application of ST in clinical practice.

METHODS

Frozen tissue blocks from patients with squamous cell carcinoma and adenocarcinoma of the nose and skull base diagnosed at our institution were prepared. The effects of different procedures and pathological tissue types on slide quality were explored and evaluated using RNA integrity number (RIN) and HE scores as criteria. The effects of different RIN values on ST sequencing data were explored.

RESULTS

A total of 43 samples were obtained from 26 patients, including 22 with squamous carcinomas and 21 with adenocarcinomas. Thirteen samples with satisfactory RNA quality control and good histological morphology were sequenced for ST. Sample isolation time <15 min and abandonment of snap-frozen isopentane significantly improved RNA quality (p = 0.004, p < 0.0001) and histomorphological integrity (p = 0.02, p = 0.02). Selection of a suitable tissue RNA extraction kit was critical for RNA quality (p < 0.0001). No difference between 6 ≤ RIN <7 and RIN >7 in ST sequencing results was found, indicating that RIN ≥6 can be used as a criterion for qualified RNA quality control. Therefore, fresh tissues washed as soon as possible with cold PBS and then dried using OCT for snap freezing are currently the best method for preparing spatial sections of nose and skull base tumor tissues of different pathological types.

CONCLUSION

This study is the first to investigate the feasibility of applying ST to different pathological types of nose and skull base tumors and to demonstrate the widespread application of ST in tumors. Rational optimization of spatial slide preparation procedures and exploration of individualized pre-sequencing protocols are used as the first stage to ensure the quality of spatial sequencing and lay the foundation for subsequent spatial analysis.

Innovative Fudan rT staging in endoscopic surgery for recurrent nasopharyngeal carcinoma

BACKGROUND

American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) rT staging have great clinical impracticality. The aim of the present study was to establish a new rT staging to guide endoscopic surgery for the treatment of recurrent nasopharyngeal carcinoma (rNPC).

METHODS

This surgical rT staging (named Fudan rT staging) was constructed using two significant risk factors: the distance from the tumor margin to the internal carotid artery, and dural invasion. Log-rank and receiver operating characteristic (ROC) curve analyses were used to evaluate its effectiveness.

RESULTS

Fudan rT staging can effectively separate the overall survival (OS) and progression-free survival (PFS) of patients with rNPC according to the different rT stages (p < 0.05). In addition, ROC analysis showed that the Fudan rT staging exhibited enhanced prognostic value for OS and PFS compared with the AJCC/UICC rT staging.

CONCLUSIONS

The innovative Fudan rT staging has a better predictive value for the survival of patients with rNPC than AJCC/UICC rT staging.

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

Objective

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

Methods

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

Results

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

Conclusions

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

Treatment of Recurrent Nasopharyngeal Carcinoma: A Sequential Challenge

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.

N6-Methyladenosine RNA Modification Landscape in the Occurrence and Recurrence of Nasopharyngeal Carcinoma

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a type of squamous head and neck cancer with variable geographic distributions, with the highest incidence in Southeast Asia. Its primary treatment is radiotherapy due to its high radio sensitivity. However, the N6-methyladenosine (m6A) landscape in NPC, including recurrent NPC, has not been reported.

METHODS

In this study, m6A RNA immunoprecipitation (RIP) sequencing and microarray sequencing were performed on 12 tissue samples tissues of patients with primary and recurrent NPC. The expression profiles of m6A-related and non-coding RNAs were constructed and explored. Then, function experiments were performed to evaluate the effects of methyltransferase (METTL)3, METTL14 and WT1 associated protein (WTAP) on progressions of NPC. Finally, immunohistochemistry (IHC) and survival analysis were performed to confirm the correlation between METTL3, METTL14 and WTAP and NPC patients' clinical outcomes.

RESULTS

This study mapped m6A RNA modification and RNA expression profiles in normal nasopharynx, primary NPC, and recurrent NPC tissues. This study also explored the role of m6A modificators in NPC development and recurrence. METTL3, METTL14, and WTAP could promote invasion and metastasis of NPC, and that these three proteins could induce radiotherapy resistance in NPC cells through DNA repair. Moreover, we found that METTL3, METTL14, and WTAP promoted an increase in exosomes within NPC microenvironment.

CONCLUSIONS

This study suggests that the alteration of m6A modification in primary and recurrent NPCs may play an important role in the development and progression of NPC.

Salvage Endoscopic Skull Base Surgery: Another Treatment Option After Immunotherapy for Recurrent Nasopharyngeal Carcinoma

BACKGROUND

Advanced recurrent nasopharyngeal carcinoma (NPC) is a relatively common nasopharyngeal skull base disease for which there is no uniform treatment modality. Not all patients are satisfied with the efficacy of immunotherapy with or without chemotherapy.

METHODS

This study included patients who underwent salvage endoscopic skull base nasopharyngectomy after immunotherapy between February 2017 and June 2021. Patient survival information was analyzed. Relevant publications were retrieved from five databases from December 1, 2011 to December 1, 2021. The outcomes of patients with advanced recurrent NPC who received programmed death 1 (PD-1) immunotherapy were collected and analyzed.

RESULTS

Nine patients who underwent skull base surgery, all of whom had previously undergone PD-1 immunotherapy, were included in this study. The 2-year overall survival (OS) and progression-free survival (PFS) rates of these patients were 25% and 29.2%, respectively. Eight publications involving 688 patients with advanced recurrent NPC were also included in this study. The combined complete response (CR), partial response (PR), and stable disease (SD) values were 2%, 23%, and 29%, respectively. The combined DCR included the three disease conditions, CR, PR, and SD, with a value of 53%. PD-1 monotherapy was more effective than PD-1 combination chemotherapy.

CONCLUSIONS

PD-1 immunotherapy may improve the remission rate in patients with recurrent NPC. Salvage endoscopic skull base nasopharyngectomy may be another option for patients with poor immunotherapeutic outcomes. For patients with advanced recurrent NPC, better evidence-based medical data are needed to determine whether they should receive immunotherapy before or after surgery.

Advances of DNA Damage Repair-Related Drugs and Combination With Immunotherapy in Tumor Treatment

Cancer therapy has been an important and popular area in cancer research. With medical technology developing, the appearance of various targeted drugs and immunotherapy offer more choices to cancer treatment. With the increase in drug use, people have found more and more cases in which tumors are resistant to DNA damage repair (DDR)-based drugs. Recently, the concept of combination therapy has been brought up in cancer research. It takes advantages of combining two or more therapies with different mechanisms, aiming to benefit from the synergistic effects and finally rescue patients irresponsive to single therapies. Combination therapy has the potential to improve current treatment of refractory and drug-resistant tumors. Among the methods used in combination therapy, DDR is one of the most popular methods. Recent studies have shown that combined application of DDR-related drugs and immunotherapies significantly improve the therapeutic outcomes of malignant tumors, especially solid tumors.