The clinical evidence suggests no statistical differences in sensitivity and specificity between LBC and CC. LBC is estimated to be on average 6% more sensitive and 4% less specific than CC across a range of cytological thresholds. There is an 83% chance that LBC is more sensitive than CC and a 72% chance that it is less specific. On average, LBC classifies approximately 1% more cell abnormalities than CC at the low-grade threshold of LSIL+. At the high-grade threshold of HSIL+, LBC may classify fewer abnormalities than CC, but the difference is not statistically different. On average, LBC may have a lower rate of unsatisfactory specimens, but the estimated differences from individual studies varied.
HPV triage of ASCUS is more sensitive to detect cervical intraepithelial lesions than repeat cytology. HPV triage has a similar specificity compared to repeated cytology. Model projections suggest that, over a woman's lifetime, LBC is likely to improve health outcomes (e.g., cancer incidence and cancer death) and increases costs when compared with CC at the same screening interval. Model projections also suggest that, over a woman's lifetime, HPV triage reduces costs and improves health outcomes when paired with any cytologic screening strategy.
Direct comparison of all screening and triage strategies show that annual screening with CC or LBC is always more costly and less effective than when paired with HPV triage. HPV triage used with LBC screening at two-year intervals is preferred to CC with HPV triage at a willingness-to-pay threshold of CAD50,000 per LY gained, and CC with HPV triage every two years is preferred to LBC with HPV triage at lower willingness-to-pay thresholds. In comparison with current practice, using liquid-based cytology with HPV triage at two-year screening intervals will reduce costs, with a similar or reduced burden of disease. Thus, the health economic evidence suggests that two-year screening strategies using HPV triage, with or without LBC, represents the best use of resources for cervical cancer screening. These results will require revision given the introduction of automated screening, HPV vaccination, and organized screening programs.
