Epidemiology, clinical characteristics and outcomes of intracranial metastases (ICM) in human papillomavirus positive (HPV+) oropharyngeal squamous cell carcinoma (OPSCC).

Abstract

e18031 Background: HPV+ OPSCC has better outcomes than HPV negative OPSCC but more distant metastatic potential. ICM in HPV+ OPSCC are rare. Data regarding risk factors, clinical presentation and outcomes after ICM diagnosis is limited. This study describes clinical characteristics and outcomes of patients (pts) with HPV+ OPSCC who develop ICM. Methods: Retrospective analysis of pts with HPV+ OPSCC and ICM between 2010 - 2024. Demographic, clinicopathologic, and survival data was collected. Skull base recurrences were excluded. Univariate and multivariate analyses used Cox proportional hazard models; continuous variables binarized by receiver operator curves. Survival assessed via Kaplan-Meier method; reported as median (95% CI). Calculations use BlueSky (v10.3.1). Results: Among 1,999 pts with HPV+ OPSCC, 16 (0.8%) had ICM. Pt characteristics and treatment are summarized in Table 1. Primary tumor sites were base of tongue (56%), tonsil (38%), and unknown (13%). Most pts (n=8, 50%) presented with stage IV disease (6 extracranial metastasis (ECM), 1 ICM only, 1 both). Frontal and parietal lobes were the most frequent ICM sites. Neurological symptoms were present in 10 (62%) pts; ICM was incidentally found in 6 (38%) pts. Median overall survival (mOS) from initial diagnosis was 34 months (21 – not reached) and median time from diagnosis to ICM was 24 months (range 1-112). mOS following ICM detection was 10.9 months (4 -18). On multivariate analysis, only surgical resection (hazard ratio [HR] 0.03, p<0.01) and radiotherapy (HR 0.01, p<0.02) were independently associated with post-ICM survival. With median follow up of 100 months, 14 pts (88%) had died; 2 (12%) were alive. Conclusions: ICM from HPV+ OPSCC are rare but devastating with a mOS <1 year from detection. Most pts were symptomatic, had de novo metastatic disease, and had other sites of metastases. Surgical resection and radiation were associated with improved OS. Multicenter efforts to investigate predictors, multiomic sequencing and identification of pt subsets who may benefit from ICM screening are warranted. Baseline characteristics of Pts with ICM in HPV+ OPSCC. Variable Summary statistics (n=16) Median age (range) 58 (34-71)  Male 14 (88%)  Smoking history 10 (60%)  Clinical stage at diagnosis Stage I:  4 (25%)  Stage II: 2 (12.5%)  Stage III: 2 (12.5%)  Stage IV: 8 (50%)  Symptoms at ICM diagnosis Incidental: 6 (38%)Neurological: 10 (62%) Seizure (n=3) Motor/Sensory symptoms (n=3) Altered mental status (n=2) Cognitive symptoms (n=1) Dizziness (n=1) ICM site Frontal lobe: 7 (44%)  Parietal lobe: 7 (44%)  Occipital lobe: 4 (25%)  Temporal lobe: 2 (13%)  Cerebellum: 2 (13%)  Concurrent ECM Bone: 11 (69%)  Lung:  9 (56%)  Lymph node: 6 (38%)  Liver: 5 (31%)  Kidney: 1 (6%)  Cranial nerve: 1 (6%)  Treatment after ICM   Radiotherapy: 15 (94%)  Chemotherapy: 10 (63%)  Immunotherapy: 9 (56%)  Surgery: 8 (50%)