Triaging HPV-positive women with p16/Ki-67 dual-stained cytology: Results from a sub-study nested into the ATHENA trial.

OBJECTIVES: In addition to genotyping for HPV16/18, dual-immunostaining for p16/Ki-67 has shown promise as a triage of HPV-positive women. We assessed the performance of p16/Ki-67 dual-stained cytology for triaging HPV-positive women undergoing primary HPV screening.

METHODS: All women ≥25years with valid cervical biopsy and cobas® HPV Test results from the cross-sectional phase of ATHENA who were referred to colposcopy (n=7727) were eligible for enrolment. p16/Ki-67 dual-stained cytology was retrospectively performed on residual cytologic material collected into a second liquid-based cytology vial during the ATHENA enrolment visit. The diagnostic performance of dual-stained cytology, with or without HPV16/18 genotyping, for the detection of biopsy-confirmed cervical intraepithelial neoplasia grade 3 or worse (CIN3+) was determined and compared to Pap cytology. Furthermore, the number of colposcopies required per CIN3+ detected was determined.

RESULTS: Dual-stained cytology was significantly more sensitive than Pap cytology (74.9% vs. 51.9%; p<0.0001) for triaging HPV-positive women, whereas specificity was comparable (74.1% vs. 75.0%; p=0.3198). Referral of all HPV16/18 positive women combined with dual-stained cytology triage of women positive for 12 "other" HPV genotypes provided the highest sensitivity for CIN3+ (86.8%; 95% CI: 81.9-90.8). A similar strategy but using Pap cytology for the triage of women positive for 12 "other" HPV genotypes was less sensitive (78.2%; 95% CI: 72.5-83.2; p=0.0003), but required a similar number of colposcopies per CIN3+ detected.

CONCLUSIONS: p16/Ki-67 dual-stained cytology, either alone or combined with HPV16/18 genotyping, represents a promising approach as a sensitive and efficient triage for colposcopy of HPV-positive women when primary HPV screening is utilized.