Should we use risk selection tests for HPV 16 and/or 18 positive cases:
comparison of p16/Ki67 and cytology
Abstract
Background: Major screening abnormalities in pre-colposcopic
stage are tests results that imply direct referral to colposcopy (and/or
expedited treatment) without performing additional high-grade squamous
intraepithelial lesions or worse (HSIL+) risk selection testing.
Currently, both clinically validated HSIL+ risk selection tests, reflex
cytology and reflex p16/Ki67 dual staining (DS), are being compared for
use in primary HPV-based screening to avoid possible overtreatment, but
there is still no sufficient data available for their performance.
Methods: Among 30,066 liquid-based cervical cancer screening
tests results, a group of 332 women was selected with available HRHPV
tests results with 16/18 limited genotyping, liquid-based cytology, DS,
and histology results from standardized colposcopy with biopsy. In HPV
16/18+ cases, three triage approaches were retrospectively analyzed.
Predictive values for detection of HSIL+ were calculated and number of
colposcopies required in each strategy. Results: Both triage
models with DS used (reflex cytology followed by DS, and reflex DS alone
in all cases) had significantly higher PPV for HSIL+ than strategy with
reflex cytology alone (44.2%/45.7% vs. 28.3%; p<0.0001). In
models with DS, less colposcopies were required (95/92 vs. 152) and less
colposcopies were needed per HSIL+ detection (2,26/2,19 vs. 3,54). Only
1 HSIL+ case was missed in both triage models with DS incorporation.
Conclusions: p16/Ki67 dual-stain may be an effective, alone or
combined with cytology, triage test to detect HSIL+ in patients with
major screening abnormalities in primary HPV-based cervical cancer
screening. Performing cytology as the first triage test improves the
strategy by enabling referrals to expedited treatment in selected cases.