Women today who are treated for high-grade cervical intraepithelial neoplasia (CIN) customarily have repeat cytologic testing to detect persistent or recurrent disease. Reported recurrence rates range from 5% to 15%. It is assumed that effective treatment eradicates both CIN and preexisting infection by high-risk human papillomavirus (HPV). The investigators developed a computer-based mathematical Markov model with which 6 follow-up regimens were compared with standard cytologic follow-up at 6, 12, and 24 months. The model parameters were based on 3 Dutch follow-up studies and a Dutch population-based screening cohort. Outcome measures included the number of cases of high-grade CIN (CIN2/3) missed after 5 years of follow-up, the number of diagnostic procedures, and cost.
Strategies including adjunctive HPV testing missed fewer cases of posttreatment CIN2/3 than did the current approach of cytologic testing at 6, 12, and 24 months. The effect was most evident with combined cytology and HPV testing at 6 and 24 months. Use of this strategy would spare one case of missed CIN2/3 for every 192 women treated. Combined testing reduced missed cases of CIN2/3 by 32% to 77%. This strategy also was less inconvenient; the number of repeat smears declined by 28% to 65%. With HPV testing alone at 6 months and combined HPV and cytologic testing 24 months after treatment, posttreatment CIN was detected at high rates, while rates of colposcopy did not increase. In addition, this strategy was less expensive that current cytologic follow-up. The cost reduction was greatest when combined testing was done only at 12 months.
These observations endorse the use of testing for high-risk HPV in women who have been treated for CIN2 or CIN 3. Apart from its clinical value, combined testing is warranted by cost savings arising from the need for only 2 rather than 3 repeat smears (provided that only HPV testing is done at initial follow-up).