This study demonstrated that repeated self-sampling for HPV testing at home was more effective in increasing participation and detecting CIN2 + and less costly than midwife-collected Pap smear cytology in primary cervical screening. Our results concerning the cost of cervical screening based on self-sampling for HPV testing are in line with those of previous studies modeling the cost-effectiveness of HPV testing in primary cervical screening. In a study from Canada it was concluded that using HPV testing both in primary screening or as triage of equivocal Pap smear results was more effective and cost-effective relative to cytology (22). In a study from the Netherlands it was predicted that replacing cytology in primary screening by way of HPV testing and cytology triage would increase the total cost, but this could be compensated for by extended screening intervals (23). A study from Australia, including a vaccinated population, showed that primary HPV testing with partial genotyping of HPV16/18 every five years was a more effective and less costly strategy than cytology screening every two years (24).
Self-sampling for HPV testing is one of the most effective (in improving participation) and cost-effective interventions as regards non-responders, and has been evaluated in several European populations (25–29). Similar to our study results, previous intervention studies for sensitivity analysis on participation rate, health care costs, Pap smears and self-sampling kits have not affected the results. Our published randomized study was the first to demonstrate an increase in participation in primary screening with vaginal self-sampling using PCR-based HPV test, as compared with midwife-collected Pap smear cytology (1). In the present study we provide a cost-effectiveness analysis of the randomized trial. The total cost per woman participating in primary screening was 4.2 times higher in the Pap smear arm than in the HPV self-sampling arm.
The estimation of treatment costs showed that the cost per treated woman was 45% higher in the Pap smear arm, since more women with cervical intraepithelial neoplasia grade 2 (CIN2) were detected by HPV self-sampling than by Pap smears. This, together with somewhat different treatment policies in different hospitals, resulted in more excisions under local anesthesia and proportionally fewer hysterectomies in the HPV self-sampling arm than in the Pap smear arm, resulting in a lower cost per treated woman. During the study period about 50% of all women visited a gynecologist for colposcopy as follow-up after treatment (‘test of cure’). According to present guidelines the recommended ‘test of cure’ is cytology and HPV testing based on a sample collected by a midwife. As previous studies have showed that only up to about 30% of patients are HPV-positive six months after treatment (30–32), only these might need a colposcopy, resulting in lower costs for the HPV self-sampling arm.
One strength of our CEA is that we retrospectively collected healthcare events for all included patients in a randomized trial. We then applied the direct medical costs reported from the financial records, together with costs of self-sampling kits and postal fees to each individual patient. The data therefore provide reliable estimates of costs.
This study included all direct medical costs, but not all direct costs (e.g. transportation costs to and from the clinic, parking fees or childcare costs) and indirect costs (i.e. those corresponding to the ‘time off work’ needed for scheduling and conducting the screening appointment) related to clinician-collected samples. These costs can be substantial (33) and including them would result in a more comprehensive estimate of the actual differences in costs between alternative strategies for primary cervical screening. ‘Time off work’ can also represent a barrier to attending clinic-based screening, and avoiding such barriers thus might lead to higher population coverage (33). In our previous CEA study we compared self-sampling for HPV testing with Pap smear cytology using a Markov model simulating the natural history of cervical cancer, plus empirical data to create a Swedish female cohort (34). We concluded that self-sampling for HPV testing is cost-effective every five years among women aged over 35 years compared with cytology-based screening with Pap smears (34).
Swedish national guidelines on primary cervical screening with HPV testing and triage with liquid-based cytology among women aged over 30 years have recently been published (35, 36). The future societal costs are estimated to decrease as a result of fewer cancer cases needing healthcare, and the near-time healthcare costs of the screening program are estimated to increase as a result of more cases needing colposcopy, treatment and follow-up (19). It is therefore of interest to assess alternative screening strategies that could both increase the participation in screening and reduce the overall costs and women suffering. This CEA on repeated self-sampling for HPV testing shows profitable results with respect to increasing participation at lower cost than conventional cytology in primary cervical screening.