3470 - Patterns of Recurrence in HPV-Associated Oropharyngeal Squamous Cell Carcinoma after Surgery Alone vs. Surgery plus De-Escalated Adjuvant Radiotherapy
Presenter(s)
A. L. Frias1, J. A. Jordan1, A. Ness2, A. W. Bogan3, J. S. Lewis4, A. V. Chintakuntlawar5, S. H. Patel6, K. Price5, R. J. Brisson1, D. K. Ebner1, S. C. Lester1, T. D. Malouff1, M. A. Neben-Wittich1, D. J. Ma1, E. J. Moore7, K. K. Tasche7, L. X. Yin7, K. Van Abel7, and D. M. Routman1; 1Department of Radiation Oncology, Mayo Clinic, Rochester, MN, 2Department of Quantitative Health Sciences, Section of Biostatistics, Mayo Clinic, Rochester, MN, 3Department of Qualitative Health Sciences, Section of Biostatistics, Mayo Clinic, Scottsdale, AZ, 4Department of Pathology, Mayo Clinic, Phoenix, AZ, 5Division of Medical Oncology, Mayo Clinic, Rochester, MN, 6Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, 7Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic, Rochester, MN
Purpose/Objective(s): Although HPV-associated oropharyngeal squamous cell carcinoma (HPV(+)OPSCC) has excellent cure rates, significant treatment-related toxicity has prompted interest in de-escalated adjuvant radiotherapy (DART). However, patterns of recurrence between surgery alone versus surgery plus DART are not well-described. Here, we compare recurrence patterns between these groups.
Materials/Methods: With IRB approval, we queried an institutional database of 2755 patients with HPV(+)OPSCC treated with surgery, radiation, and/or chemotherapy from 1990 to 2025 across three sites of an academic center. We identified patients who had undergone surgery alone with recurrence or surgery with adjuvant DART and selected patients who developed recurrence within two years. Clinical and recurrence characteristics were collected. Group comparisons were performed using the two-sample t-test for continuous variables and the Fisher Exact test for categorical variables.
Results:
64 patients with recurrence were identified (surgery alone n=48; surgery plus DART n=16). Baseline characteristics were similar between groups. However, the surgery plus DART group had higher-risk nodal features, including higher node positivity (100% vs. 67%, p<0.01), node number (mean 4.7 vs. 1.5, p=0.01), and extranodal extension (75.0% vs. 18.8%, p<0.01), as anticipated. Most neck dissections were ipsilateral (76.6%), whereas most adjuvant radiotherapy (RT) was bilateral (93%). There were 68 recurrent sites (surgery alone n=50; surgery plus DART n=18) among the 64 patients. Median time to recurrence in the surgery plus DART group was 11.1 months (IQR: 5.5 – 12.5) and 8.2 months (IQR: 5.4 – 12.5) for surgery alone. Among recurrence events, local recurrence predominated after surgery alone, whereas distant recurrence predominated after surgery plus DART. Most regional recurrences occurred in the involved and dissected neck for both groups.Conclusion:
Among patients with HPV(+)OPSCC who recurred within two years of surgery, surgery alone demonstrated more frequent local failures followed by regional failures whereas recurrences among those treated with surgery plus DART were more frequently distant metastases followed by regional failures. Regional failure was most common at the sites of initial involvement. In the surgery plus DART group, the local regional benefit of RT is evident with greater systemic dissemination risk based on significantly higher-risk baseline features for recurrence. As adjuvant RT becomes increasingly focal and de-escalated, further evaluation of recurrence patterns, including in-field, marginal, and out-of-field recurrences, will be critical in refining target delineation. Table 1 – Patterns of Recurrence| Type of Recurrence* | DART (N=18) | Surgery (N=50) |
| Local | 2 (11.1%) | 26 (52.0%) |
| Regional | 7 (38.9%) | 21 (42.0%) |
| Distant | 9 (50.0%) | 3 (6.0%) |
| *p=0.001 |