Review of HPV testing for primary cervical cancer screening

Abstract

Cytology-based cervical cancer screening achieved undisputable success in reducing the incidence and mortality of cervical cancer in many countries of the world, especially high-income countries. However, in lowand middle-income countries substantial reductions in cervical cancer incidence rates have not been achieved, mainly due to the difficulties in realization of complex conditions for implementing high quality cytology-based cervical cancer screening programs. Most international guidelines, including the World Health Organisation (WHO) Global Strategy, now recommend high-risk human papillomavirus (hrHPV) testing as the preferred cervical screening test, for several reasons, primarily due to its sensitivity, less subjectivity in diagnosis and possibility of easier program organization and implementation. The advantages of primary hrHPV screening include higher sensitivity of technology compared to cytology based examinations, and increased specificity in populations where large proportions of women have been vaccinated against the human papillomavirus (HPV), while the high-negative predictive value enables prolongation of screening intervals to 7 to 10 years, which increases the cost effectiveness of the screening programme, when applied at population level. Also, primary hrHPV screening for cervical cancer can be carried out by self-taken samples which increases the feasibility of such cervical cancer screening programme. However, implementing primary hrHPV cervical cancer screening requires at the same time organised system of monitoring the implementation of the program, coordination and quality assurance of all processes within the implementation of cervical cancer screening.Effective hrHPV primary cervical cancer screening programme requires the triage of hrHPV positive women to maximise the detection of clinically relevant cervical lesions for further investigation. Most of the countries that introduced hrHPV primary cervical cancer screening use visual inspection with acetic acid (VIA), cytology based examination or HPV geno-typing with cytology for triage testing. The choice of triage strategy depends on various factors, including availability of resources, effectiveness and cost of procedures to recall women for triage testing as well as the capacity and quality of existing health services to deliver the triage tests. Implementation of self-sampling also requires a number of issues to be addressed, including communication to motivate participation and to inform women about the self-sampling procedure, delivery of the self-sampling kits and return of the samples to the laboratories, laboratory procedures, communication of results, recalling screen-positive women for further examination and triage and motivating them to attend for follow-up and treatment. Finally, the introduction primary screening for HPV on the mucous membrane of the cervix should be accompanied by awareness-raising programs to improve the information and knowledge of women and the entire population about the importance of the cervical cancer screening, which would improve the results of population based cervical cancer screening programs and increase the women's participation.