The application of BMRT-HPV viral load to secondary screening strategies for cervical cancer

OBJECTIVE: Evaluate the significance of BMRT HPV assay viral load and its performance for secondary screening. METHODS: BMRT-HPV reports type-specific viral loads/10,000 cells. We tested 1,495 physician collected, stored specimens from Chinese Multiple-center Screening Trial (CHIMUST), that were positive by Cobas, SeqHPV, and/or Cytology (≥LSIL); and 2,990 age matched, negatives in a nested case control study. We explored the relationship between BMRT HR-HPV viral load and cervical lesions, determined alternative CIN2+ cut-points by ROC curve, and evaluated BMRT HR-HPV for primary / secondary cervical cancer screening. RESULTS: The viral loads of HPV16/18, 12 other subtypes HR-HPV and 14 HR-HPV were statistically different in all grades of cervical lesions (P<0.05, among which HPV16, 33 and 58 showed the strongest relationship (P<0.01). The viral load of HR-HPV also increased with the grade of cervical lesions (P<0.05). The sensitivity for CIN2+ and CIN3+ of BMRT was comparable to Cobas (92.6% vs 94.3%, 100% vs 100%, P>0.05), specificity was higher than Cobas (84.8% vs 83.3%, 83.5% vs 82.0%, P<0.001). When using HPV16/18 viral load(log cut-point ≥3.2929), plus the viral-load of 12 other subtypes (log cut-point ≥3.9625) as secondary triage, compared with Cobas HPV16/18+ plus cytology ≥ASC-US as triage, the sensitivities for CIN2+ and CIN3+ were similar (P>0.05). However, the BMRT HR-HPV viral load combined with subtypes did not require cytology. CONCLUSION: BMRT is as sensitive as Cobas4800 for primary cervical cancer screening. BMRT HR-HPV viral load combined with subtypes can be used as a secondary strategy for cervical cancer screening, especially for areas with insufficient cytological resources.