A study of diagnostic failure of loop conization in microinvasive carcinoma of the cervix

The aim of this study was to evaluate the specimen adequacy and the histological interpretation of loop conization for microinvasive cervical carcinoma.

We retrospectively reviewed the histopathological findings of the original cone specimens together with the final hysterectomy specimens in patients with microinvasive carcinoma of the cervix. From 1990 to 1995, 63 consecutive patients with microinvasive carcinoma of the cervix were included in the study, of which 35 patients underwent loop conization and 28 underwent cold-knife conization. All patients had a hysterectomy.

The mean width, depth, and cone volume of the conization specimens were 2.44 cm, 2.15 cm, and 3.96 cm3, respectively, in the loop group versus 2.3 cm, 2.35 cm, and 4.38 cm3 in the cold-knife group. No significant differences were seen between the two groups. The application of loop conization was completed in a single slice in 27 patients (77.1%) and multiple slices by the loop in 8 (22.9%), in spite of the attempt to perform conization in a one-pass application when possible. In assessing these cone specimens microscopically, the rate of transection of tissue was significantly higher in the loop cone than in the cold-knife cone (17.1% versus 0%, P = 0.02). Because of transection of tissue and misorientation, pathologic determination of the depth and width of stromal invasion was undetermined in two loop cone specimens compared with none in the cold-knife cones.

Our study suggests that cold-knife conization is a preferred method in assessing microinvasive carcinoma of the cervix if multiple applications of loop conization are inevitable.