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Primary HPV Testing Matches Cotest Protection Against Cervical Precancer Long-Term
Over ten years of follow-up, women who tested HPV-negative had a cumulative precancer risk of just 0.41% (95% CI, 0.17%–0.65%), nearly identical to those who were cotest-negative at 0.37% (95% CI, 0.13%–0.60%), suggesting that adding cytology to HPV screening provides negligible additional protection while increasing costs. Both strategies substantially outperformed cytology alone, where normal cytology regardless of HPV status carried a 1.28% cumulative risk (95% CI, 0.78%–1.78%).
What Was Studied
This study investigated whether combining HPV testing with cytology (cotesting) meaningfully reduces long-term cervical precancer risk compared with standalone primary HPV screening or cytology alone. The question is directly relevant to health system decisions globally, as jurisdictions weigh the clinical benefit and added cost of cotesting programs against the efficiency gains of primary HPV-based screening.
How It Was Studied
Researchers conducted a cohort study by linking participant data from a randomised clinical trial to British Columbia’s comprehensive population-level cervical cancer screening registry. Women were recruited between 2006 and 2012, and follow-up extended from trial exit through ten years post-exit, providing unusually long-duration surveillance data. The analytic cohort comprised 8,078 women (median age 49 years) who completed exit cotesting, with results stratified by HPV status, cytology status, and all four combinations thereof. Precancer incidence was the primary outcome, defined as cervical intraepithelial neoplasia grade 2 or higher (CIN2+), and was estimated using Kaplan-Meier cumulative incidence methods.
What Was Observed
- HPV-positive women with abnormal cytology carried the highest precancer burden, with a 10-year cumulative incidence of CIN2+ of 43.47% (95% CI, 23.45%–58.26%). Women who were HPV-positive but had normal cytology still faced a substantially elevated risk at 22.21% (95% CI, 11.49%–31.62%), reinforcing that HPV positivity is the dominant signal even when cytology appears reassuring.
- HPV-negative women with abnormal cytology had a comparatively low cumulative risk of 4.83% (95% CI, 0%–10.03%), but this group represented less than 1% of the study population (69 of 8,078 women, or 0.85%), meaning this category is rare and contributes minimally to population-level screening strategy.
- HPV-negative women with normal cytology had the lowest observed risk at 0.37% (95% CI, 0.13%–0.60%) over the entire follow-up period, and this risk level was statistically indistinguishable from the HPV-negative group overall (0.41%; 95% CI, 0.17%–0.65%), demonstrating that cytology adds no meaningful risk stratification once HPV negativity is established.
- Normal cytology alone, irrespective of HPV result, was associated with more than three times higher cumulative precancer risk (1.28%; 95% CI, 0.78%–1.78%) compared with HPV-negative screening, reinforcing that cytology-based programs are substantially less reassuring over a decade of follow-up.
Why This Matters
These findings provide high-quality longitudinal evidence directly relevant to ongoing policy debates about optimal cervical cancer screening architecture. The near-equivalence of HPV-negative and cotest-negative risk profiles over ten years is a meaningful signal for health economists and policymakers evaluating whether the incremental reassurance of adding cytology justifies its cost. The data also quantify the magnitude of the gap between HPV-based and cytology-based approaches in a way that shorter-term studies cannot, lending greater weight to the case for transitioning to primary HPV screening.
How to Read This Result
This was a single-province Canadian cohort with specific demographic composition, and generalisability to populations with different HPV prevalence, vaccination coverage, or healthcare infrastructure should be interpreted with appropriate caution.
Limitations
The abstract does not explicitly report study limitations.