Evaluation of a Cervical Cancer Screening Program Based on HPV Testing and LLETZ Excision in a Low Resource Setting

Abstract

We conducted studies in Vanuatu to evaluate potential screening and treatment strategies to assist with control of cervical cancer. In a pilot study of 496 women, visual inspection and cytology were evaluated as screening tests for detection of CIN 2 or worse (CIN2+), observed in 21 of 206 subjects biopsied on the basis of abnormal visual inspection or cytology. Sensitivity of visual inspection with Lugol's Iodine for detection of CIN2+ on biopsy was 0.63, specificity was 0.32, and the positive predictive value was 0.09. For HSIL cytology, sensitivity was 0.99, specificity was 0.77, and the positive predictive value was 0.88. HSIL cytology was significantly more sensitive and had a significantly higher PPV for CIN 2+ than visual inspection (p<0.01). In a further study of 514 women, we compared testing for HR HPV and cytology as predictors of biopsy proven CIN 2+. Sensitivity of HSIL cytology for CIN2+ as established by loop excision of the cervix was 0.81, specificity was 0.94, and positive predictive value was 0.48. Sensitivity of a positive test for HR HPV for detection of CIN2+ was non-significantly different from cytology at 0.81, specificity was 0.94, and positive predictive value was 0.42. Combining the two tests gave a significantly lower sensitivity of 0.63, a specificity of 0.98, and a positive predictive value of 0.68. For women over 30 in a low resource setting without access to cytology, a single locally conduced test for high risk HPV with effective intervention could reduce cervical cancer risk as effectively as intervention based on cytology conducted in an accredited laboratory.

Prevalence of Cervical Human Papillomavirus (HPV) Infection in Vanuatu

“…Our present survey also confirmed a substantial burden of precancerous and cancerous cervical lesions in the general female population of Vanuatu (4). Not only the prevalence of HSIL þ in our present study was much higher than in well-screened populations in Western countries (20) but also it tended to increase steadily with a woman's age.…”

“…Among women younger than 30 years, only HPVpositive HSILs were recalled. Histology examinations were conducted by accredited Australian diagnostic pathology providers (4).…”

“…With respect to HPV prevalence, a study of different screening modalities in 488 women aged between 30 and 50 years based on hybrid capture 2 (HC2) was carried out in Port Vila in 2006. It showed an overall prevalence of HR HPV types of 9.0% (4).…”

“…This information was not available from the study by McAdam and colleagues (4) and is deemed to be essential to introduce and monitor the impact of HPV vaccine (5). We, therefore, conducted a new survey in Vanuatu using a well-validated PCR assay for HPV testing and HC2.…”

Development and Implementation of Papillomavirus Prophylactic Vaccines

“…One clear lesson to date is that education about the vaccine is key to its successful deployment, and that education needs to be directed at health care professionals, governments, recipients, parents, and schools to ensure effective delivery programs (46). A recent program in Vanuatu, a developing Pacific island nation, established the high prevalence of high-risk HPV infection (47) and of cervical dysplasia (48) in that country. This has enabled a joint program with GSK to deliver vaccines through schools, which achieved a 93% uptake rate of the full vaccine program across eligible children on Efate Island.…”