Population based cohort study of risk of cervical cancer among patients with untreated CIN2

Cervical intraepithelial neoplasia grade 2 (CIN2) is a precursor of cervical cancer and may pgress to cancer if left untreated. Consequently, CIN2 has been the threshold for surgical excision. However, several studies have shown spontaneous regression rates of CIN2 of 50% to 69% within two years. A population based cohort study in Denmark included 27,425 women with CIN2, of whom 45% had active surveillance and 55% were immediately surgically treated. The figure shows that during the first two years of follow-up, the risk of cervical cancer was comparable between the two groups. Thereafter, the risk of cervical cancer increased in the active surveillance group, reaching 2.65% (95% CI 2.07-3.23) after 20 years, whereas it remained stable in the immediately treated group at 0.76% (0.58-0.95). The authors conclude that leaving CIN2 lesions untreated was associated with increased long-term risk of cervical cancer.