Endoscopic CT-Navigated Intraoperative Mapping Biopsies of the Cranial Base in the Management of Recurrent Nasopharyngeal Cancer.

Presentation: S002
Topic: Nasopharynx / Paranasal Sinus / Skull Base
Type: Oral
Date: Friday, July 23, 2021
Session: 1:00 PM - 1:50 PM Skullbase Plus
Authors: Peter Costantino, MD, FACS1; Rakhna Araslanova, MD, FRCSC1; Tristan Tham, MD2
Institution(s): 1New York Head and Neck Institute; 2Zucker School of Medicine at Hofstra/Northwell, New York,NY


Introduction:

Salvage therapy for recurrent nasopharyngeal carcinoma (rNPC) is required in 9-40% of patients. Diagnosis of rNPC is difficult, because up to 20% of all treated patients develop osteoradionecrosis (ORN) leading to similar symptoms. Conventional or office-based biopsies (OBB) are often unreliable for diagnosis. Moreover, imaging and OBB often cannot estimate the burden of recurrent disease in the presence of concurrent ORN.


Objective:

Our primary objective was to compare a novel, anatomic intraoperative mapping biopsy (IMB) technique to the traditional OBB for diagnosing rNPC. Our secondary objective was to introduce IMB as a tool for anatomical mapping in order to determine rNPC resectability.


Methods:

A retrospective cohort review of patients, who presented with suspected rNPC from 2007-2018 was conducted in our single, tertiary care center. Patients meeting inclusion criteria for the study had a history of NPC treated with either primary radiation with or without chemotherapy and underwent OBB for suspected recurrence followed by IMB. IMB is a standardized protocol for CT-navigated, anatomical intraoperative nasopharyngeal sampling, which helps delineate potential recurrent tumor. All patients underwent contrast enhanced MRI and PET/CT before undergoing IMB.


Results:

Twenty-three consecutive patients met the inclusion criteria and were incorporated into the analysis. Fifteen patients (65.2%) were diagnosed with rNPC during the follow up period. IMB demonstrated sensitivity of 86.7% (95%CI: 59.5-98.3%) and specificity of 100%. In contrast, OBB sensitivity was 53.3% (95%CI: 26.6-78.7%) and specificity of 25% (95%CI 3.19-65.09). The difference in specificity was statistically significant with McNemar’s test (p<0.05).

Ten patients undergoing IMB had negative results, and two of these were eventually found to be positive for rNPC (False negative rate of 20%). In contrast, there were 9 OBB tests that had negative results, with 7 confirmed to have rNPC (False negative rate of 78%). 

Four patients were deemed unresectable on IMB. However, 9 patients were candidates for resection, and consequently underwent nasopharyngectomy with clear surgical margins. The nasopharyngectomy specimen positivity correlated with anatomic sampling on IMB.


Conclusion:

Despite the modest sample size, our study demonstrates the significant value in anatomic, surgeon-guided biopsies for diagnosis and treatment planning of suspected rNPC. IMB gives the surgeon a higher chance of correct diagnosis by targeting the high-risk areas for recurrence in the nasopharynx. Another advantage is simultaneous evaluation for potential resectability or re-irradiation planning. Therefore, IMB should be included into the armamentarium of surgeons for diagnosis, and potential treatment planning of patients with suspected rNPC.