Objective: To identify risk factors for residual or recurrent cervical intraepithelial neoplasia (CIN) after large loop excision of the transformation zone with clear margins.
Methods: We did a case-control study of women treated with loop excision for CIN who had adequate follow-up and in whom margins were believed to be clear. Women with clear margins in whom no subsequent lesions were found (controls) were compared with women who presented with subsequent CIN (cases). Epidemiologic and colposcopic risk factors for recurrence were analyzed. Multiple logistic regression analysis was done to identify independent risk factors.
Results: In 31 of 635 women studied (4.9%), subsequent lesions were diagnosed. Univariate analysis identified glandular involvement, satellite lesions, and age over 40 years in cases as significant. Multiple logistic regression analysis confirmed that these three characteristics were independent risk factors, with odds ratios of 4.9 (95% confidence intervals 1.9, 12.3), 19 (7.5, 48.2), and 6.7 (2.8, 15.8), respectively. Subsequent lesions were identified by colposcopy or cytologic testing during the first postoperative year in all but one case.
Conclusion: Age over 40 years, glandular involvement, and satellite lesions were related to the reappearance of CIN after loop excision with clear margins. These findings could be used to define appropriate follow-up protocols.