Omission of excisional therapy is associated with an increased risk of invasive cervical cancer after cervical intraepithelial neoplasia III.

Background: Using data from the population-based Geneva Cancer Registry we evaluated the risk of invasive cervical cancer following carcinoma in situ (CIS) or cervical intraepithelial neoplasia (CIN) III according to type of treatment.

Methods: Included in the study were all women diagnosed with CIS/CIN III in Geneva (Switzerland) between 1970 to 2002 (n=2658) and followed for invasive cervical cancer occurrence until 31st December 2008. We calculated age and period standardised incidence ratios (SIR) and multiadjusted hazard ratios (HR) of invasive cervical cancer by treatment groups.

Results: During follow-up, 17 women developed invasive cervical cancer, conferring a SIR of 5.1 (95% confidence intervals [CI] 3.0-8.1). The risk of cervical cancer was significantly increased until 10 years after diagnosis. The risk was highest for women ≥ 50 years (SIR=7.3, 95% CI: 2.7-15.8) and for women who did not undergo excisional treatment (SIR=25, 95% CI: 12.0-46.0). The multiadjusted HR of invasive cervical cancer for women who did not undergo surgical excisional treatment was 9.4 (95% CI: 2.8-32.2) compared with women who did.

Conclusion: Women diagnosed with CIS/CIN III are at increased risk of developing invasive cervical cancer. This risk is particularly high for women who did not have excision of cervical lesions.