The Benefit of Early PET/CT Surveillance in HPV-Associated Head and Neck Squamous Cell Carcinoma
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OBJECTIVE: 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. DESIGN: Retrospective. SETTING: Single tertiary academic referral center. PATIENTS: 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. MAIN OUTCOME MEASURES: 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. RESULTS: 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. CONCLUSIONS: 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.