932P - Accuracy and prognostic implications of extranodal extension on radiologic imaging in HPV-positive oropharyngeal cancer (HNCIG-ENE): A multinational, real-world study

Background

Extranodal extension on radiology (iENE) is used routinely as an eligibility criterion for surgical treatment. However, studies report widely varying sensitivities, specificities and interobserver correlation.

Methods

We assessed the prognostic power, sensitivity and specificity of iENE in comparison to ENE on pathology (pENE) in a large multinational, multicentre cohort of consecutive HPV+OPC cases in a real-world setting. Outcomes were overall survival (OS) and accuracy.

Results

821 p16+OPC subjects included from 10 centres in 5 countries. 21.3% cass with no iENE were found to have pENE, and 56.8% cases with pENE were misclassified as having no ENE on radiology (ie no iENE). Sensitivity and specificity for iENE were 44.5% (95% CI 37.8 – 51.4 %) and 87.6% (95% CI 84.1-90.6 %) respectively, and varied significantly between centres. Negative predictive value was 75.3% (95%CI 72.3-77.5%). Subgroup analyses showed significantly increased sensitivity and specificity if patients had both CT and MRI: 84.6% (95%CI 65.1- 95.6%, p<0.001) and 94.5% (95%CI 82.3-99.4%, p=0.022) respectively, compared to only CT [47.45% (95% CI 38.86, 56.15) and 78.43% (72.15, 83.87))r] or MRI [18.60% (95% CI 8.39, 33.40, p<0.001) and 96.73 (92.54, 98.93, p<0.001). Specialist radiologists showed better specificities to non-specialists. On multivariable analysis, iENE positivity was not a statistically significant predictor of OS (adjusted hazards ratio (aHR) 1.50 (95%CI 0.97-2.32, p=0.071)) or disease-free survival (aHR1.41, 95CI 0.95-2.09, p=0.089).

Conclusions

In current real-world practice, iENE accuracy was modest, varied widely between centres, and was not independently prognostic of outcomes in HPV+OPC. However, iENE accuracy and prognostic power may be increased significantly by using combined CT and MRI scanning, experienced head and neck radiologists and more inclusive diagnostic criteria. Work is urgently needed to develop and validate consensus diagnostic criteria and protocols to enhance the clinical utility of iENE. Till then, clinicians should be cautious about making treatment decisions based on iENE.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

H. Mehanna.

Funding

Has not received any funding.

Disclosure

H. Mehanna: Financial Interests, Personal, Invited Speaker: MSD, Merck; Financial Interests, Personal, Advisory Board: Merck, Nanobiotix, Seagen, Seattle Genetics; Financial Interests, Personal, Member of Board of Directors: Warwickshire Head Neck Clinic; Financial Interests, Personal, Stocks/Shares: Warwickshire Head Neck Clinic; Financial Interests, Institutional, Research Grant: AstraZeneca; Non-Financial Interests, Leadership Role, Chair of the Head and Neck Cancer International Group: HNCIG; Non-Financial Interests, Other, Research grant Co-investigator: Cancer Research UK; Non-Financial Interests, Other, Research Grant Co-Investigator: European Commission; Non-Financial Interests, Other, Research Grant co-investigator: NIH; Non-Financial Interests, Principal Investigator, Research Grant: NIHR; Non-Financial Interests, Member: ASCO, BACO. C. Henson: Financial Interests, Institutional, Advisory Board: EMD Serono; Non-Financial Interests, Personal, Officer: HNCIG Young Investigators. L. McDowell: Financial Interests, Institutional, Advisory Board: MSD. W. Lydiatt: Financial Interests, Personal, Invited Speaker, honorarium for speaking: Sarah Cannon Cancer Center; Non-Financial Interests, Leadership Role, President elect and President starting May 16, 2024 for one year: American Head and Neck Society; Non-Financial Interests, Leadership Role, Chair of Head and Neck Staging Core groupEditorial Board member: AJCC. S. Yom: Financial Interests, Institutional, Research Grant: Bristol Myers Squibb, EMD Serono, Nanobiotix; Financial Interests, Personal, Royalties: Springer, UpToDate; Financial Interests, Personal, Speaker’s Bureau: Elsevier, ASTRO. M. Oliva Bernal: Financial Interests, Personal, Invited Speaker: Merck, MSD, BMS; Financial Interests, Personal, Advisory Board: Merck, MSD; Financial Interests, Personal, Writing Engagement: MSD; Financial Interests, Personal, Invited Speaker, Teaching activities: MSD, Merck; Financial Interests, Personal, Other, IDMC: Transgene; Financial Interests, Personal and Institutional, Funding: Roche; Financial Interests, Institutional, Local PI: ALX Oncology, MSD, ISA Therapeutics BV, Roche, Ayala Therapeutics, Abbvie, Bayer, Boehringer Ingelheim, Merck, Debiopharm, Seagen, Gilead, Beigene, NYKODE; Financial Interests, Institutional, Funding: GSK; Non-Financial Interests, Institutional, Product Samples: Roche. R. Leemans: Financial Interests, Personal, Advisory Board: MSD. All other authors have declared no conflicts of interest.