Modeling the Balance of Benefits and Harms of Cervical Cancer Screening with Cytology and Human Papillomavirus Testing.

BACKGROUND

Benefits of screening should outweigh its potential harms. We compared various metrics to assess the balance of benefits and harms of cervical cancer screening.

METHODS

We used a cervical cancer natural history Markov model calibrated to the Canadian context to simulate 100,000 unvaccinated women over a lifetime of screening with either cytology every 3 years or human papillomavirus (HPV) testing every 5 years. We estimated the balance of benefits and harms attributable to screening using various metrics, including colposcopies/life-year gained, and net lifetime quality-adjusted life-years (QALY) gained, a measure integrating women's health preferences. We present the average (minimum-maximum) model predictions.

RESULTS

Cytology-based screening led to 1,319,854 screening tests, 30,395 colposcopies, 13,504 life-years gained over a lifetime, 98 screening tests/life-year gained, 2.3 (1.6-3.3) colposcopies/life-year gained, and a net lifetime gain of 10,735 QALY (5,040-17,797). HPV-based screening with cytology triage in the same population would lead to 698,250 screening tests, 73,296 colposcopies, 15,066 life-years gained over a lifetime, 46 screening tests/life-year gained, 4.9 colposcopies/life-year gained (2.9-11.1), and a net lifetime gain of 11,690 QALY (4,409-18,742). HPV-based screening was predicted to prevent more cancers, but also incur more screening harms than cytology-based screening.

CONCLUSIONS

Metrics using colposcopies as the main harm outcome favored cytology-based screening, whereas metrics based on screening tests and health preferences tended to favor HPV-based screening strategies.

IMPACT

Whether HPV-based screening will improve the balance between benefits and harms of cervical cancer screening depends on how the balance between benefits and harms is assessed.