3453 - Is What You See What You Get? Predicting Pathologic Nodal Status from Preoperative Imaging in Human Papillomavirus-Related Oropharyngeal Cancer
Presenter(s)
L. A. del Balzo1, M. Riedel2, A. S. Kaka3, S. Rudra1, N. C. Schmitt3, J. E. Bates1, A. Jethanandani1, K. L. Baugnon4, N. F. Saba5, and W. A. Stokes1; 1Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, 2Department of Data Analytics, Winship Cancer Institute of Emory University, Atlanta, GA, 3Department of Otolaryngology, Winship Cancer Institute of Emory University, Atlanta, GA, 4Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, 5Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA
Purpose/Objective(s): Pathologic nodal (pN) status informs selection of adjuvant therapy in human papillomavirus-related oropharyngeal cancer (HPVOPC). Both ECOG-ACRIN 3311 (EA3311) and the American Joint Committee on Cancer 9th Edition (AJCC9) have introduced novel paradigms for pathologic risk-stratification. Care teams selecting patients for surgical- versus (chemo)radiotherapy-based approaches may rely on radiographic features to predict pathologic findings and thereby guide adjuvant therapy disposition. However, it is poorly understood whether these features can reliably predict contemporary pathologic risk groupings.
Materials/Methods: A single-institution retrospective study evaluated 101 consecutive patients with cT0-2 HPVOPC undergoing transoral robotic surgery + neck dissection (TORS+ND) from 2023-2025. Based on the radiographic assessment of the total number of involved nodes and extranodal extension, each patient was assigned both a radiographic nodal (rN) status (derived from AJCC9 pN classification) and a radiographic EA3311 risk group (derived from EA3311 pathologic risk grouping criteria). These were then compared to each patient’s true pN status (AJCC9) and pathologic EA3311 risk group. Agreement between classifications was assessed by Cohen’s ? and quadratic-weighted ? (?_w).
Results: The majority of patients were male (84%), white (91%), never-smokers (57%), and had tonsil primary (57%). Median interval from imaging to surgery was 28 days (IQR 18-36). Radiographic and pathologic status were cross-tabulated in the Table.
Radiopathologic concordance in AJCC9 N status was 47% (?_w=0.49), with 29% of patients upstaged and 24% downstaged. The highest rate of pathologic upstaging was observed among rN0 patients (47%), followed by rN1a patients (36%). The highest rates of pathologic downstaging were noted among rN2 (43%) and rN1b patients (41%). Radiographic ENE demonstrated low sensitivity for pathologic ENE (30%; ?=0.27), and occult ENE accounted for the majority of nodal upstaging events. Radiopathologic concordance in EA3311 risk group was 59% (?_w=0.38), with 15% of patients upstaged and 26% downstaged. The highest rate of risk group upstaging was observed among rLow patients (29%). The highest incidence of pathologic downstaging was noted among rHigh patients (64%).Conclusion: Radiographic features led to inaccurate AJCC9 and EA3311 pathologic risk grouping in nearly half of HPVOPC cases undergoing TORS+ND, with meaningful portions of patients experiencing pathologic upstaging or downstaging. Our study underscores the need for improved radiographic risk-stratification tools to guide definitive treatment selection and predict adjuvant therapy disposition.
| Nodal Status | |||||
| pN0 | pN1a | pN1b | pN2 | pN3 | |
| rN0 | 8 (53%) | 4 (27%) | 3 (20%) | - | - |
| rN1a | - | 18 (64%) | 6 (22%) | 4 (14%) | - |
| rN1b | - | 18 (41%) | 15 (34%) | 10 (23%) | 1 (2%) |
| rN2 | 1 (7%) | 2 (14%) | 3 (22%) | 7 (50%) | 1 (7%) |
| rN3 | - | - | - | - | - |
| EA3311 Group | |||||
| pLow | pInt | pHigh | |||
| rLow | 30 (71%) | 9 (22%) | 3 (7%) | ||
| rInt | 17 (38%) | 25 (56%) | 3 (6%) | ||
| rHigh | 3 (21%) | 6 (43%) | 5 (36%) | ||