The performance of single and combination test strategies using visual inspection, cytology, high-risk HPV DNA and HPV16/18 to screen South African women with and without HIV-infection

Background

Cervical cancer screening strategies should ideally be informed by population-specific data. Strategies recommended for secondary prevention, are often inadequately studied in populations with high cervical disease burdens. This report describes the test performance measured against CIN2 + /CIN3 + histology in HIV-positive women (HPW) and HIV-negative women (HNW) with the aim to determine the most effective strategies to identify South African women at risk.

Methods

Primary screening using visual inspection, cytology and HPV DNA (cobas®) was performed in two South African provinces on 456 HPW and 639 HNW participating in the multicentric DiaVACCS trial. Histology was obtained for 91.7% screen-positive and 42.7% screen-negative participants, and unavailable histology was determined by multiple imputation to adjust for verification bias. Cross-sectional test performance was calculated for single and combination test strategies with and without intermediate risk categories using different cut-offs. Minimum acceptability for sensitivity and specificity, treatment and follow-up numbers were considered to evaluate strategies.

Results

The only single test to reach acceptability in HPW was cytology (LSIL) [sensitivity 71.2%; specificity 90.5%; treatment 33.4%]; in HNW only HPV (hr) qualified [sensitivity 68.2%; specificity 85.2%; treatment 23.5%]. The universally best performing strategy which also resulted in smaller treatment numbers without intermediate risk group was primary HPV(hr), with treatment of both HPV(16/18) and cytology (ASCUS +) [HPW: sensitivity 73.6%; specificity 89.7%; treatment 34.7%. HNW: sensitivity 59.1%; specificity 93.6%; treatment 13.9%].

DNA testing for hrHPV (any) and hrHPV (16/18) was the best universally acceptable strategy with an intermediate risk category (early follow-up) in HPW [sensitivity 82.1%; specificity 96.4%; treatment 17.1%; follow-up 31.4%] and HNW [sensitivity 68.2%; specificity 96.7%; treatment 7.6%; follow-up 15.9%]. In comparison, using both HPV (16/18) and cytology (ASCUS +) as secondary tests in hrHPV positive women, decreased follow-up [HPW 13.8%, HNW 9.6%], but increased treatment [HPW 34.7%, HNW 13.9%].

Conclusion

Using hrHPV (any) as primary and both HPV16/18 and cytology as secondary tests, was universally acceptable without an intermediate risk group. Strategies with follow-up groups improved screening performance with smaller treatment numbers, but with effective management of the intermediate risk group as prerequisite.