The Benefit of Early PET/CT Surveillance in HPV-Associated Head and Neck Squamous Cell Carcinoma

Abstract

To evaluate the ability of posttreatment positron emission tomography and computed tomography (PET/CT) to predict ultimate disease status in patients with head and neck squamous cell carcinoma and known human papillomavirus (HPV) status. Retrospective. Single tertiary academic referral center. Clinical and radiographic data, including HPV status, were available for 62 patients with head and neck squamous cell carcinoma who underwent treatment from 2005 to 2010. The first posttreatment PET/CT scan, performed between 4 and 16 weeks (median, 9 weeks) after treatment, was categorized as negative, probably negative, or positive for residual disease. The PET/CT and clinical follow-up results, including disease status, were obtained every 3 months thereafter. Among the 62 patients, 35 results (56%) were negative, 15 (24%) were probably negative, and 12 (19%) were positive. Eight of the 27 HPV-negative patients were PET/CT positive compared with 4 of the 35 HPV-positive patients (Cochran-Armitage trend test, P=.11). The median follow-up for disease-free patients was 21 months from the completion of the treatment. Disease-free survival was associated with PET/CT outcome (log-rank P<.001) and HPV status (log-rank P=.01). Using recurrence at 2 years as a reference standard, the early PET/CT scans had a specificity of 69% (95% confidence interval [CI], 46%-91%) and a negative predictive value of 79% (95% CI, 57%-99%). All PET/CT-negative HPV-positive patients (n=6) were free of disease at 2 years, although this proportion was not statistically different from the PET/CT-negative HPV-positive patients in this small cohort. A negative posttreatment PET/CT result may have the potential to identify patients who are at very low risk of recurrence. The HPV status may augment the predictive utility of an initial negative PET/CT result.