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BMJ. 2014 Jan 16;348:g130. doi: 10.1136/bmj.g130.

Long term duration of protective effect for HPV negative women: follow-up of primary HPV screening randomised controlled trial.

Author information

1
Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Box 281, 171 77 Stockholm, Sweden.

Abstract

OBJECTIVES:

To assess whether the increased sensitivity of screening for human papillomavirus (HPV) may represent overdiagnosis and to compare the long term duration of protective effect against cervical intraepithelial neoplasia grade 2 or worse (CIN2+) in HPV based and cytology based screening.

DESIGN:

13 year follow-up of the Swedescreen randomised controlled trial of primary HPV screening.

SETTING:

Organised cervical screening programme in Sweden.

PARTICIPANTS:

12,527 women aged 32-38 attending organised screening were enrolled and randomised to HPV and cytology double testing (intervention arm, n=6257) or to cytology only, with samples frozen for future HPV testing (control arm, n=6270).

MAIN OUTCOME MEASURES:

Cumulative incidence of CIN2+ and CIN3+ (Kaplan Meier curves). Longitudinal test characteristics were calculated for cytology only, HPV testing only, and cytology and HPV testing combined, adjusting for censoring.

RESULTS:

The increased detection of CIN2+ in the intervention arm decreased over time. After six years, the cumulative incidence of CIN3+ was similar in both trial arms, and after 11 years the cumulative incidence of CIN2+ became similar in both arms. The longitudinal sensitivity of cytology for CIN2+ in the control arm at three years was similar to the sensitivity of HPV testing in the intervention arm at five years of follow-up: 85.94% (95% confidence interval 76.85% to 91.84%) v 86.40% (79.21% to 91.37%). The sensitivity of HPV screening for CIN3+after five years was 89.34% (80.10% to 94.58%) and for cytology after three years was 92.02% (80.59% to 96.97%).

CONCLUSIONS:

Over long term follow-up, the cumulative incidence of CIN2+ was the same for HPV screening and for cytology, implying that the increased sensitivity of HPV screening for CIN2+ reflects earlier detection rather than overdiagnosis. The low long term risks of CIN3+ among women who tested negative in HPV screening, support screening intervals of five years for such women.

TRIAL REGISTRATION:

Clinicaltrials.gov NCT00479375.

PMID:
24435414
PMCID:
PMC3898575
DOI:
10.1136/bmj.g130
[Indexed for MEDLINE]
Free PMC Article

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