HPV DNA test is performed in a cytology laboratory by trained cytotechnologist as a triage test after borderline cytology or in follow-up after excisional treatment of cervical intraepithelial neoplasia. The aim of the study was to analyze the application of the HPV test in routine cytology laboratory practice in the detection of patients with increased risk of HSIL.
We retrospectively analyzed the results of 19,459 HPV tests (Hybrid Capture 2, Qiagen, Germany) performed between 2005 and 2015 and compared with cytological diagnosis on conventional Pap smear. We also analyzed data of initial cytology and HPV test result from 1157 patients in a six-year follow up period after HPV test was made. A positive outcome represents a histological diagnosis of HSIL +.
Out of the 19,459 HPV tests, 41.9% were positive, of which 21.5% of negative cytology, 39.5% of ASCUS, 71.6% of ASC-H, 77.3% of LSIL, 86.2% of HSIL,16.9% of AGC and 75% of AIS. Out of 25 cases of cytological diagnosis of cervical cancer HPV test was negative in two histologically verified cervical cancer and in five cases of endometrial cancer. Of 1157 patients with HPV test made in 2009, 652 (56.4%) had abnormal cytology, and 473 (40.9%) had positive HPV test. The mean age of patients was 37 years (range 16-77 years). In the six-year follow up period histological analysis was performed in 213 patients and verified HSIL+ in 173 patients which is 25% of all initial abnormal cytology and 34% positive HPV tests HSIL + was found in 2.5% of patients with initially negative cytology, 8.3% of ASCUS , 10.9% of LSIL , 10% of AGC, 56.5% of ASC-H , 63.5% of HSIL and in 100% of cytological diagnosis of cancer. For all the tested samples, the HPV test showed 94.2% sensitivity, 68.4% specificity, 34% positive predictive value and 98.5% negative predictive value. Reflex HPV testing in the triage of ASCUS showed 86.2% sensitivity, 65.9% specificity, 18.7% positive predictive value and 98.1% negative predictive value. In the six-year follow up with the initial ASCUS cytology in 8.3% cases verified HSIL + lesions, and with additional triage HPV testing this percentage rises to 18.7%.
The percentage of positive HPV test increases with the severity of cytologic diagnosis. The high negative predictive value confirmed the value of the test in the triage of borderline cytology. Knowledge of cytologist and clinician of the positive HPV test may improve the selection of patients with an increased risk of HSIL lesions.