INVASIVE CERVICAL-CANCER AFTER CONSERVATIVE THERAPY FOR CERVICAL INTRAEPITHELIAL NEOPLASIA

Background Conservative outpatient therapy for cervical intraepithelia l neoplasia (CIN) by ablative or excisional techniques is widely used. The main objective of this treatment is the prevention of invasive ce rvical cancer. We assessed the rate of invasive disease and the durati on of the risk of developing invasive cervical cancer after such treat ment. Methods Four UK centres have used life-table methods to analyse the long-term results of conservative treatment of GIN. We combined an d updated data from these studies to investigate the rate of invasive disease after treatment and the duration of that risk. Findings The da ta comprised 44 699 woman-years of follow-up, with 2116 women under ob servation 8 years after treatment. 33 women developed invasive cancer, 14 of whom had microinvasion. The cumulative rate of invasion 8 years after treatment was 5.8 per 1000 women and the rate of invasive cance r during this period was 85 (95% CI 60-119) per 100 000 woman-years. T he risk of developing cancer did not change throughout the 8 years of follow-up. Interpretation These data show that conservative outpatient therapy in women with CIN reduces the risk of invasive cancer of the cervix by 95% during the first 8 years after treatment. However, even with careful, long-term follow-up, the risk of invasive cervical cance r among these women is about five times greater than that among the ge neral population of women throughout that period. Careful follow-up is essential for at least 10 years after conservative treatment of CIN.