engleski

Organised screening programmes in the era of HPV vaccination

Cervical screening has been very successful in countries where the resources exist to ensure high quality of cytology and good coverage of the population at risk. Indeed, in those countries, cervical cancer incidence and mortality rates have been substantially reduced ; up to 80% in Canada, the USA and some European Nordic countries. The understanding of the cause of cervical cancer, a persistent infection with high-risk (oncogenic) human papillomavirus (HPV) types, enables the development and implementation of HPV testing in clinical practice as a complement test to inexplicit cytology. HPV testing has also being evaluated in large scale clinical trials in women older than 30-35 years as a primary screening test followed by cytology triage, visual inspection and/or colposcopy, and treatment. In addition, prophylactic vaccination against the most common HPV types 16 and 18, available since six years, can also prevent at least 70% of cervical cancer cases. Thus, nationwide population-based organised cervical cancer prevention programme that includes both, primary prevention (HPV vaccination) and secondary prevention (screening) could efficaciously reduce cervical cancer rates. However, the lack of awareness of the benefits of such prevention measures largely undermines its acceptance in many countries in the world and even in Europe. Therefore, comprehensive organised education has to precede the implementation of novel medical approaches such as HPV testing and HPV vaccination. Furthermore, offering free services within a nationally funded programme of cervical cancer prevention (invitation to HPV vaccination and screening) could be the best solution for cervical cancer control. However, the price of the services (Pap testing, HPV testing and HPV vaccination) is the limiting factor for the implementation of such programme in many countries, especially in low and middle income countries. Moreover, cervical cancer policies have to be adapted to the specific needs and the availability of resources of each country. For instance, countries with well established and with good quality control of cytology will probably choose cytology for the primary screening test rather than HPV testing. However, in countries where HPV vaccination has good coverage over the years and where the prevalence of cervical abnormalities and the positive predictive value of cytology will notably decrease, the HPV testing as primary screening would be reasonable choice. Other points to be considered besides the nature of the screening test are the age to start and to stop screening, and the screening intervals between normal test results ; yearly screening is discouraged, while intervals of 3-5 years are recommended starting at the age range 20 to 30 till the age of 60. Thus, the choice of the nature of the primary screening test (cytology or HPV testing), the definition of the population to be screened, the length of the screening intervals, the nature of the follow-up strategy, and the HPV vaccination coverage will largely influence the cost-effectiveness of the cervical cancer screening programme. Anyhow, future cervical cancer control has to primarily rely on cervical screening of both vaccinated and non-vaccinated women because HPV vaccines will reduce, but not eliminate, the risk of cervical cancer.

cervical cancer; HPV vaccination

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