Developed countries are moving fast to replace cytology-based cervical screening with HPV primary testing. Our primary objective was to establish feasibility of HPV testing for primary screening in Malawi and to identify/address the major challenges to implementation, including outcomes of different collection devices and media. We also aimed to determine prevalence of HPV genotypes in the Nkhoma region.
Specimens were obtained from women attending routine VIA (Visual Inspection with Acetic acid) clinics in Nkhoma Hospital catchment area. VIA assessments were carried out by competent providers. HR-HPV prevalence was established using samples collected in Preservcyt® and tested by Xpert®HPV according to manufacturer’s instructions. Modifications were also tried, including reduction in collection volume, change of collection medium, use of self-collected samples and different collection devices. A sensitive multiplex PCR based assay (Papilloplex AnyHPV) was used for genotyping on a subset of samples selected according to the VIA result (139 VIA -; 156 VIA+; 42 VIA suspicious cancer).
HR-HPV positivity using Xpert HPV was ~20%(n=750). Multiple infections were common and HR-HPV prevalence in HIV+ women was 43%. For HR-HPV, concordance was good between Xpert and Papilloplex HPV tests (k=0.68). In women with suspicious cancers HPV16,18 and 45 predominated (22.7%, 11.4% and 11.4%). The most frequently detected HPV type in VIA+ women was HPV16 but Xpert P3 group (HPV52>35>31>33>58) dominated. A number of VIA+ women were HPV negative, most were not due to LR-HPV presence. HPV+ results were frequently reported in VIA- women, with HPV16 the most frequent individual type, while P3 predominated and LR-HPV was detected in ~20%. Reduction of collection medium to 5ml, alternative media and self-collected samples gave comparable HPV results.
HPV16 was the commonest individual type detected in women who are VIA+ /suspicious cancer and in VIA- women. HPV31 and related types (Xpert P3) is the most commonly detected subgroup in VIA+ and VIA- women but not in those with suspicious cancers.
Xpert HPV showed high concordance with Papilloplex for HR-HPV. The latter test is more sensitive and detected LR-HPV, but is less suitable for LMIC4. Xpert® HPV is straightforward, has rapid turnaround and should be validated with low cost collection systems.
There was high correlation between VIA suspicious cancers and HR-HPV positivity but disagreement between HPV positives and VIA positives requires further analysis before considering HPV testing for primary screening.
REFERENCES
Cubie HA, Morton D, Kawonga E et al. JCV 2017; 87:1-4.
Campbell C, Kafwafwa S, Brown H et al. IJC 2016;139:908-15.
Kawonga E, Mwenitete I, Mautanga M et al. Poster#143, HPV2017, Cape Town, March 2017
Bhatia R, Kawonga E, Mhango E et al. Abstract # EUROGIN 2017, this meeting
ACKNOWLEDGEMENT
We are grateful to the Scottish Government International Development Fund for Malawi for funding 2013-2016 (MW01).