Triage by methylation-marker testing versus cytology in women who test HPV-positive on self-collected cervicovaginal specimens (PROHTECT-3): a randomised controlled non-inferiority trial.

BACKGROUND

Cytology is a widely used method of triaging women who test positive for human papillomavirus (HPV). However, self-sampled specimens, which can substantially increase participation in screening programmes, are not suitable for accurate cytological assessment. We investigated whether direct DNA methylation-based molecular triage on self-sampled cervicovaginal specimens was non-inferior to cytology triage on additional physician-collected cervical samples in the detection of cervical intraepithelial neoplasia grade 2 (CIN2) or worse in women who did not attend cervical screening programmes.

METHODS

In this randomised controlled non-inferiority trial, we invited women (aged 33-63 years) registered as non-attendees of cervical screening in the Netherlands in 2007 to submit a self-collected cervicovaginal sample for HPV testing. Using a computer-generated sequence, we randomly allocated women who tested positive for high-risk hrHPV on a self-sample to either triage by cytology on an additional physician-taken smear or direct triage on the self-sample by methylation analysis of MAL and miR-124-2 genes (1:1; stratified by age and region, with block sizes by age group). Triage-positive women in either group were referred for colposcopy. The primary endpoint was detection of CIN2 or worse, analysed by intention to treat. The non-inferiority margin was 0·80. This study is registered in the Primary Trial Register of the Netherlands, number NTR6026.

FINDINGS

We invited 46,001 women to participate, 12,819 of whom returned self-sampled material; 1038 samples tested positive for high-risk HPV. Between Nov 1, 2010, and Dec 31, 2011, after exclusion of women who were ineligible, we enrolled and randomly allocated 515 women to methylation triage and 509 to cytology triage. The detection of CIN2 or worse with methylation triage was non-inferior to that with cytology triage (90 [17%] of 515 women vs 75 [15%] of 509 women; relative risk 1·19, 95% CI 0·90-1·57). Referral for colposcopy was more common in the molecular group (284 [55%] women) than in the cytology group (149 [29%] women; p<0·0001). Mean time to CIN2 or worse diagnosis was shorter in the molecular triage group (96 days, range 44-101) than in the cytology triage group (158 days, 71-222; p=0·00084).

INTERPRETATION

DNA methylation analysis of MAL and miR-124-2 genes on HPV-test-positive self-samples is non-inferior to cytology triage in the detection of CIN2 or worse, opening the way to full molecular screening.

FUNDING

Midden-West and Oost Screening Organisations and Stichting Achmea Gezondheidszorg.