Randomized study comparing two techniques of conization: Cold knife versus loop excision

Objective. To compare the histomorphologic and colposcopic results of cold knife conization and loop excision. Methods. Sixty-six women were randomly allocated to have the cone specimen removed by cold knife excision (n = 38) or loop excision (n = 28). Subjects eligible for inclusion were those who presented histologically verified grade 3 cervical intraepithelial neoplasia (CIN) or grade 2 CIN with squamocolumnar junction not seen. Results. The mean height of the cone specimens was greater in the cold knife group [18.9 mm (SD = 5.5) and 12.8 mm (SD = 4.3), respectively; P = 0.0001], as was the frequency of clear margins (100 and 80%, respectively; P = 0.001), In the loop excision group, thermal injuries were present in half of the cone sections. The median (range) thickness of thermal injury was 0.98 mm (0-1.5 mm) in the ectocervix and 0.95 mm (0-1.75 mm) in the endocervix. Histologic evaluation of the endocervical margins was not possible in 2 cases (7%). At follow-up colposcopy, evaluation of the entire squamocolumnar junction was possible in 15 (39%) and 20 (71%) women, respectively (P < 0.01). Four patients in the cold knife group and 6 in the loop group had histologically confirmed persistent dysplasia (P > 0.05), yielding success rates of 90 and 79%, respectively (P > 0.05). Conclusions. Loop excision provides a sample that is adequate for histologic evaluation in most cases, results in the same success rate as cold knife conization, and allows optimal colposcopic surveillance in significantly more cases than cold knife excision. (C) 1999 Academic Press.