Despite a well-established cervical cancer screening program in Norway, the insidence of CxCa in young women is increasing, peaking at 35 years. Twenty five percent of all women diagnosed with CxCa had normal cytology within 3 years of cancer diagnosis. We wanted to estimate the detection rate of CIN2+ in women with normal Pap smears by rescreening Pap smears from HPV mRNA 16, 18, and 45 positive samples. HPV 16, 18 and 45 cause 90% of cervical cancers in young women.
From April 2016, the Department of Pathology, University Hospital of North Norway, introduced a study by rescreening all normal Pap smears that had a positive HPV mRNA test (PreTect SEE). Women with revised cytology were followed up according to national guidelines.
Of 26 948 women with Pap smear, 184 (0.7%) had normal cytology and a positive HPV mRNA test. After rescreening of the index cytology, 63 women had abnormal cytology. At present 42 women have had colposcopy, resulting in 7 women with normal biopsies, 21 CIN1, 9 CIN2 and 5 CIN3. The positive predictive value of CIN2+ among women with biopsy was 33.3 % (14/42).
By testing all women with normal cytology with a specific HPV mRNA test, an increase in screening program sensitivity can be achieved. When more women with CIN2+ are detected in the first screening round, fewer women will develop cervical cancer before next screening. The volume of rescreened smears (0.7%) is very low but adds significant improvement of screening sensitivity and increases quality in educating the screeners by rescreening presumably false negative Pap smears.