Increased detection of high grade CIN, when using electrical impedance spectroscopy as an adjunct to routine colposcopy, is maintained when used across international boundaries: Prospective data from nine European countries.

ABSTRACT

OBJECTIVE: To evaluate the performance of EIS (ZedScan) with colposcopy in the detection of high grade CIN (HG-CIN) in different health care settings. METHOD: Pooled analysis of data from 26 colposcopy centres in 9 countries. All women underwent colposcopy and ZedScan examination. Data was recorded prospectively via a proforma. Indications for referral to colposcopy were according to national guidelines. Pathology was reported according to national guidelines. RESULTS: 5257 women were examined by 82 colposcopists, median 93 women per centre (range 41 - 2684), 3 users per centre (range 1-8). Referral indications were; 19.3% high grade cytology, 50.4% low grade, 30.3% clinical or HPV positive / cytology negative. The prevalence of HG-CIN was 26.5%; 79.1% in high grade referrals, 16.7% low grade, 9.4% clinical or HPV positive / cytology negative. The use of ZedScan detected an extra 269 cases of high grade CIN (24% increase) (7.5% increase for high grade referrals, 57.9% for low grade and 52% for clinical or HPV positive/cytology negative). Based upon colposcopic impression (CI), the sensitivity of colposcopy for CIN2 + was 74.1% compared with 91.6% for colposcopy with ZedScan (Chi2 p < 0.0001). The PPV for a ZedScan directed biopsy varied according to referral cytology and colposcopic impression (19.5% to 85.7%). 489 women underwent treatment at first visit, when ZedScan suggested treatment, 95.1% had HG-CIN/HG-CGIN or cervical cancer. The pooled results for the whole 26 centres were consistent with the results obtained for the largest centre (Sheffield) alone and also with the results with this largest centre excluded. CONCLUSIONS: The addition of EIS (ZedScan) increases detection of HG-CIN with the PPV for a ZedScan directed biopsy consistent with the published literature. Results were similar in multiple healthcare settings. With more women being referred to colposcopy at low risk of HG-CIN, due to HPV vaccination and primary HPV screening, this study confirms the value of a real time adjunctive technology.