Completeness of excision and follow up cytology in patients treated with loop excision biopsy

To assess the relation between the grade and the status of follow up cytology, the completeness of loop excision biopsies with cervical intraepithelial neoplasia (CIN), and the findings at follow up cytology, as well as the differences between complete and incomplete exclusion, using the odds ratio. Treatment failure was assessed.

1600 women with CIN (290 CIN1, 304 CIN2, 1006 CIN3) were followed for a minimum of six months and a maximum of 10 years. A database was created and comparisons performed. The mean age of the patients was 37 years.

Excision was complete in over 84% of loops. Residual disease and recurrence of high grade dyskaryosis was more common in women with CIN 3 than CIN 2 or 1. No high grade dyskaryosis was seen in the fifth follow up smear in patients with CIN 1 and CIN 2. Residual, recurrent, and persistent disease was most common in patients with incompletely excised CIN at ectocervical and endocervical margins and deep margins of resection than in patients with completely excised CIN. The odds ratios were significantly higher in the women who had incomplete excision of CIN at ectocervical, endocervical, both ecto- and endocervical, and deep margins of resection compared with those with apparent complete excision of CIN lesions. One patient developed invasive squamous cell carcinoma 44 months after loop excision which showed CIN 3 invading endocervical crypts and extending to both ectocervical and endocervical margins of resection.

At long term follow up, patients with CIN who have residual disease are at increased risk of persistent disease and should therefore be followed up regularly with cytology and colposcopy. The findings support national policy of returning women with treated CIN of any grade to normal recall after five years except for cases of CIN3 where excision was incomplete or equivocal. In these cases follow up with annual smear for 10 years is recommended.