A cost-effectiveness analysis of anal cancer screening in HIV-positive women.

OBJECTIVE

Anal cancer rates have increased in HIV+ patients. The prevalence of anal intraepithelial neoplasias (AINs) and progression to anal cancer in HIV+ men who have sex with men has been well described, and screening is cost-effective. Our objective was to determine whether anal cancer screening in HIV+ women is cost-effective.

MATERIALS AND METHODS

A Markov model analysis of 100 HIV+ women was constructed. All women had a CD4 count less than 200 and were assumed to be on antiretrovirals. Rates of AIN were based on previous studies. Progression rates were extrapolated from previous data on HIV+ men who have sex with men. The 5-year model included 3 screening approaches: none, annual, and biennial. Anoscopy and biopsy were performed after an abnormal cytologic result. Low-grade AIN was followed with repeat cytology, and high-grade AIN was treated surgically. Anal cancer was treated surgically followed by chemotherapy and radiation. Sensitivity analyses (SAs) were performed to account for variable rates of AIN progression, anal cancer mortality, and anal cancer and HIV quality-adjusted life years.

RESULTS

The incremental cost-effectiveness ratio of biennial anal cancer screening compared to no screening was $34,763. Cost-effectiveness was maintained across all assumptions in SA except for decreased progression rate of high-grade AIN to anal cancer.

CONCLUSIONS

Biennial anal cancer screening in HIV+ women with CD4 counts less than 200 is cost-effective. Annual screening was not cost-effective, likely because of the slow progression of AIN to anal cancer. Further data on rates of AIN progression in HIV+ women based on CD4 count are needed to determine whether screening is cost-effective in women with higher CD4 counts.