Dual staining for p16/Ki67 is a more specific test than cytology for triage of HPV-positive women

Globally, cervical cancer (CC) screening is moving from cytology-based to HPV screening or a combination of both (co-testing). Most HPV-positive women clear the virus and do not develop relevant disease. Additional triage approaches are needed to reduce unnecessary colposcopy referrals. The p16/Ki67 dual stain cytology test (DSCT) is one of the most promising, but it has not (yet) been included as a recommendation in European guidelines. Previous studies in Spain on this issue are lacking. We studied the performance of p16/Ki67 DSCT for the triage of HPV-positive women in Navarra to detect precursor lesions (PLs) and CC compared to cytology only. We selected 1865 HPV-positive women with p16/Ki67 DSCT results and 304 women with an available biopsy result. Sensitivity, specificity and predictive values of the p16/Ki67 DSCT to detect underlying PLs and CC compared to cytology were calculated, using the biopsy as the gold standard. Cytology and p16/Ki67 DSCT showed similar sensitivity (99.0% vs. 98.0%), but cytology had significantly lower specificity (6.9 vs. 39.1%). Of the CIN2+/HPV+ women, triage using cytology only would have resulted in 40.2% true PLs and CC, while using p16/Ki67 DSCT this was 98.0% qualifying the women for colposcopy referral. Our results show that p16/Ki67 DSCT detects more than twice as many true PLs and CC than cytology only in this population. Thus, this test can be considered as an important additional tool in HPV testing-based screening strategies, to avoid unnecessary colposcopy referrals and to reduce health care costs.