Differences in imaging characteristics of HPV-positive and HPV-Negative oropharyngeal cancers: a blinded matched-pair analysis

Abstract

Background and purpose: Human papillomavirus-positive oropharyngeal cancers typically have younger age of onset, limited tobacco exposure, and more favorable prognosis than HPV-negative oropharyngeal cancers. We assessed whether HPV-positive and HPV-negative oropharyngeal cancers have consistent differences in pretreatment imaging characteristics.

Materials and methods: A retrospective review of 136 pretreatment CT examinations of paired HPV-positive and HPV-negative oropharyngeal cancers matched for T stage, tumor subsite, and smoking status was performed with the reviewing radiologist blinded to HPV status and clinical stage. Demographic/clinical characteristics and imaging characteristics of primary lesions and metastatic nodal disease were compared by use of Fisher exact testing. The McNemar χ(2) test was used for the matched-pair analysis.

Results: By imaging, HPV-negative tumors were more likely to demonstrate invasion of adjacent muscle (26% versus 6%, P = .013). HPV-positive primary tumors were more likely to be enhancing and exophytic with well-defined borders, whereas HPV-negative primary tumors were more likely to be isoattenuated and demonstrate ill-defined borders, though these results were not statistically significant. HPV-positive tumors were more likely to demonstrate cystic nodal metastases than HPV-negative tumors (36% versus 9%, P = .002).

Conclusions: In this matched and blinded analysis of the imaging differences between HPV-positive and HPV-negative oropharyngeal cancers, HPV-positive carcinomas often had primary lesions with well-defined borders and cystic nodal metastases, whereas HPV-negative primaries more often had poorly defined borders and invasion of adjacent muscle.

Fig 1.

HPV-negative SCCOP demonstrating deep muscular invasion involving the extrinsic muscles of the tongue with submucosal spread. Axial contrast-enhanced CT image shows a large and deeply invasive T4 base of tongue lesion, extending anteriorly into the oral tongue.

Fig 2.

HPV-positive SCCOP with typically well-defined borders. Axial contrast-enhanced CT image shows a midline T2 base of tongue mass with well-defined margins (arrows). Level II left lymph node metastasis demonstrates extracapsular extension.

Fig 3.

HPV-negative SCCOP demonstrating ill-defined borders. Axial contrast-enhanced CT image shows a mass in the left tonsil, with poorly defined borders, especially anteriorly.

Fig 4.

HPV-positive SCCOP demonstrating a cystic nodal metastasis. Axial contrast-enhanced CT image shows an obvious bulky midline left-sided base of tongue cancer (with characteristically well-defined borders) and a predominantly cystic mass in level IIa.