Unique Patterns of Distant Metastases in HPV-Positive Head and Neck Cancer

BACKGROUND: HPV-positive head and neck squamous cell carcinoma (HPV+ HNSCC) demonstrates favorable outcomes compared to HPV-negative SCC, but distant metastases (DM) still occur. The pattern of DM in HPV+ HNSCC is unclear. METHODS: 1,494 HNSCC patients were treated from 2006 to 2012. Recurrence time and metastatic sites in HPV+ HNSCC (Group 1) were compared to patients with HPV-negative/unknown cancers arising in the hypopharynx, larynx, or glottis (Group 2) as well as to patients with HPV-negative/unknown cancers in theoral cavity, oropharynx, hard palate, or tonsil (Group 3). RESULTS: 7/109 (6.4%) patients with HPV+ HNSCC developed DM. The median time to metastases was 11 months. At a median follow-up of 18-25 months, there was no difference in the overall rate of DM for the HPV+ HNSCC group compared to Group 2 (HPV-/unknown) (p = 0.21) and Group 3 (HPV-/unknown) (p = 0.13). There was a significant difference in the rate of DM to the lung in the HPV+ HNSCC group compared to Group 2 (HPV-/unknown) (p = 0.012) and Group 3 (HPV-/unknown) (p = 0.002). CONCLUSIONS: There was no observed difference in the time to development of DM between the HPV-/unknown and HPV+ HNSCC groups. However, the HPV+ HNSCC group showed a higher rate of DM to the lung compared to the HPV-/unknown -HNSCC group (p = 0.002).