Feasibility of self-sampling and human papillomavirus testing in rural and urban areas for cervical cancer prevention in Bolivia: an observational study

Abstract

Cervical cancer is a major health problem in Latin America. In 2019, the Italian Agency for Development Cooperation (La Paz regional site) conducted a pilot study to estimate the prevalence of high-risk human papillomavirus (HPV) and the feasibility of HPV screening in Bolivia through self-sampling and portable and transportable laboratory instruments for HPV testing in urban and rural areas. Women aged 20-65 years from La Paz (urban area), Torotoro (rural area), and Acasio (rural area) were enrolled by invitation from local public health centres between Dec 1, 2019, and June 30, 2021. Self-sampling was carried out with the Viba-Brush system (Rovers, Oss, Netherlands) and samples were preserved in ThinPrep containers (Hologic Corporation, San Diego, CA, USA). The GeneXpert system (Cepheid, Sunnyvale, CA, USA) for high-risk HPV testing detects HPV E6 and E7 DNA via real-time PCR in a mobile system of easy execution requiring minimal manual intervention. The system provides results in about 1 h. Women with a positive test for HPV types 16, 18, or 45 were invited for a follow-up colposcopy. Data analysis was done considering the following age groups: <20, 20-34, 35-44, and 45-65 years. The study terminated later than expected (in June, 2021, instead of in November, 2020) due to the COVID-19 pandemic, and follow-up test retrieval is still ongoing. 2201 women were enrolled: 622 (28·3%) in La Paz, 768 (34·9%) in Torotoro, and 811 (36·8%) in Acasio. Only one sample was collected from each participant. 2076 (94·3%) of 2201 samples were adequate (yielding a negative or positive result) for HPV testing. 264 (12·7%) samples were positive for high-risk HPV. The observed prevalence was higher in the 20-34 age group (145 [15·5%] of 938) than in the 35-44 age group (60 [10·5%] of 571) and in the 45-65 years age group (37 [8·3%] of 444). Ages were not recorded for 123 samples, which are not included in the prevalence-per-age analysis. HPV positivity was detected in 94 (15·3%) of 614 samples from women from La Paz, 86 (12·9%) of 667 samples from patients from Torotoro, and 84 (10·6%) of 795 samples from patients from Acasio (risk ratio urban vs rural 1·4 [95% CI 1·04-1·80], p=0·029). Overall positivity was 58 (7·3%) of 795 for HPV type 16 and 38 (1·8%) of 2076 for HPV types 18 and 45. From the follow-up data available to date, all high-grade lesions detected on follow-up colposcopy were related to HPV types 16, 18, or 45, isolated or in co-infection with other high-risk HPV types. The total and age-adjusted prevalence of high-risk HPV infection in rural and urban areas in Bolivia, as measured with a validated test for screening, is similar to that observed in Europe and the USA. Our study shows that a screening protocol for HPV testing with self-sampling would be feasible in urban and rural areas in Bolivia, and that the high prevalence of cervical cancer in Bolivia is likely to be related to the scarcity of screening programmes, and not to a higher occurrence of high-risk HPV infections. Carrying out HPV tests locally avoids the issues associated with transport and storage of the material collected, and allows the participant to wait in the clinic for the test result. However, the cost of HPV testing, at about €15 per test, is still a major hurdle for low-income countries. Joint initiatives between the national scientific community, international institutions, and manufacturers could allow widespread testing of HPV to be rolled out in Bolivia and other countries with similar contexts. Italian Agency for Development Cooperation (Italian Ministry of Foreign Affairs), as a part of an ongoing technical assistance programme with the Bolivian Ministry of Health.