Between 2000 and 2010, an estimated 122,000 long-term, mainly Polish and Lithuanian immigrants arrived in Northern Ireland, 51% of whom are served by our cervical smear screening service. HPV triage for low-grade smears commenced in January 2013, results categorised as HPV16, HPV18 or “Other High Risk HPV subtype” (OHR HPV). A Pathology trainee had the impression that "other national" ON samples were more likely to be OHR HPV than HPV 16/18 positive, prompting this Audit.
Nationality was confirmed on a central screening database. We audited patients whose smear was low grade (LG), high risk HPV positive whose subsequent biopsy was CIN11 or more (116 indigenous NI and 13 ON ). We also audited a smaller sample of smears reported as High Grade (HG) dyskaryosis (46 NI and 16 ON). The High Risk HPV Profile of each group was then determined.
LG smear to CINIII biopsy: 43% of the NI group have OHR HPV detected , contrasting with 54% in the ON group. HG smear to CINIII biopsy: 29% of NI population have OHR HPV, contrasting with 39% in the ON group. Amalgamated results (HG + LG): 39% of NI group have OHR HPV, contrasting with 45% in the ON group. Interestingly the 2 cases of invasive carcinoma, both from NI patients in this audit, were OHR HPV detected. HPV results for biopsy proven CIN II – amalgamated (HG + LG) results: 57% of the NI population have OHR HPV, contrasting with 45% in the ON group.
The sample size in this audit is too small for rigorous statistical analysis. However they hint at an increase in prevalence of OHR HPV in the ON group, in which HPV 18 also appears lower. The proportion of OHR HPV, in both NI and ON groups in samples initially reported as High grade, CINIII biopsy +ve is much lower, raising a few interesting possibilities. Is disease associated with HPV 16/18 easier to recognise, or are there sampling issues in obtaining the smear? The audit highlights the degree of OHR HPV associated with precancer, CINIII. If confirmed, do these data have implications for the utility of HPV16/18 vaccination?