- 2 consecutive positive tests for circulating tumor HPV DNA (ctHPVDNA) detect recurrence of HPV-associated oropharyngeal cancer with high sensitivity and specificity.
Why this matters
- ctHPVDNA compares favorably to other surveillance technologies such as positron emission tomography (PET)/CT, which is prone to false positives.
- Prospective analysis.
- 115 patients who underwent curative-intent chemoradiotherapy (CRT) had a 3-month post-CRT PET/CT scan.
- Patients were evaluated clinically every 2-4 months during years 1 and 2 and every 6 months in years 3-5.
- Blood samples were analyzed every 6-9 months for ctHPVDNA.
- Funding: University Cancer Research Fund; Burroughs Wellcome Fund; NIH; others.
- Median follow-up, 23.7 months.
- Recurrence rate, 13%.
- 87 of 115 patients never had detectable ctHPVDNA at 2 consecutive tests throughout follow-up, and none developed recurrence:
- Negative predictive value, 100% (95% CI, 96%-100%).
- 16 patients had 2 consecutive positive ctHPVDNA tests, and 15 of them had a recurrence:
- Positive-predictive value of 2 consecutive tests: 94% (95% CI, 70%-100%).
- Sensitivity: 100%.
- Specificity: 99%.
- The median interval between ctHPVDNA positivity and recurrence, as confirmed by a biopsy, was 3.9 (range, 0.37-12.9) months.
- 2 consecutive tests were not tested prospectively.