Cervical cancer screening may be able to occur later, less often in HPV-vaccinated women, study suggests
When compared with no intervention, vaccination alone with no screening produced a 64.6% mean reduction in lifetime cervical cancer risk, and screening strategies increased this risk reduction to a range of 88% to 98%. The lowest cost-effectiveness ratio was seen with cytology-only screening every 5 years starting at age 35, compared with vaccination alone.
Given the lower risk of cervical cancer in women vaccinated against human papillomavirus (HPV), such patients may be able to begin screening later and receive screening less often than is currently recommended, according to a recent analysis.
Researchers used an individual-based microsimulation model of HPV and cervical cancer to project health and economic outcomes associated with screening women vaccinated with the bivalent (HPV-2) or quadrivalent vaccine (HPV-4), or the nonavalent vaccine (HPV-9). Results were published online on Oct. 17 by the Journal of the National Cancer Institute.
The researchers evaluated 25 screening strategies among women fully vaccinated with HPV-2 or HPV-4 in preadolescence. When compared with no intervention, vaccination alone with no screening produced a 64.6% mean reduction in lifetime cervical cancer risk, and screening strategies increased this risk reduction to a range of 88% to 98%. The lowest cost-effectiveness ratio ($20,950 per quality-adjusted life-year [QALY]) was seen with cytology-only screening every 5 years starting at age 35, compared with vaccination alone.
Optimal strategies in this population were 5-year screening starting at age 30 with either cytology or HPV testing, at respective thresholds of $50,000 and $100,000 per QALY gained. Currently recommended strategies of cytology testing every 3 years starting at age 21, with or without a switch to co-testing at age 30, were inefficient, and co-testing was not optimal under any condition. Screening this cohort starting at age 21 or more often than every 5 years was either not cost-effective or had ratios exceeding $200,000 per QALY gained.
Women vaccinated with the HPV-9 vaccine had an 85.3% mean reduction in lifetime risk of cervical cancer compared with no intervention, and cancer reductions ranged from 91% to 99% with screening. For these women, optimal screening strategies involved later start ages and lower frequencies than those vaccinated with HPV-2 or HPV-4, and only strategies involving primary HPV testing were efficient. With a ratio of $40,210 per QALY, the most cost-effective strategy was primary HPV testing every 10 years starting at age 35.
The study authors noted limitations to the analysis, such as limited generalizability to women vaccinated at later ages or those who receive fewer than 3 doses. They also noted that they assumed that women adhered to screening, which may vary in practice and impact the relative cost-effectiveness of screening strategies. “[O]ur model-based projections suggest that less-intensive screening algorithms can provide greater health benefit at lower harms and costs than current screening guidelines, which do not differentiate recommendations based on HPV vaccination status,” they wrote.