Objective: To investigate the occurrence of invasive carcinomas following local destructive treatment for cervical intraepithelial neoplasia (CIN) and to evaluate the factors responsible.
Design: A multicentre retrospective study.
Subjects: Forty-nine women registered with the British Society for Colposcopy and Cervical Pathology from 24 centres throughout Great Britain between 1985 and 1992, who had been treated by local destructive methods for CIN and who subsequently developed invasive carcinoma of the cervix.
Results: Of the 49 women whose details were submitted, 42 had squamous cell carcinoma, six adenosquamous carcinoma and one adenocarcinoma. Eight had microinvasive carcinomas (Stage Ia) at the time of diagnosis, 24 had Stage Ib tumours and eight Stages II to IV. Thirteen women have died. Thirty-five women had been treated by laser vaporization, ten by cold coagulator, two by diathermy and two by cryosurgery. In 19 women (39%) the diagnosis of invasive carcinoma was made on the first follow up visit or within one year of treatment. Five patients did not present with invasive disease until more than five years after treatment.
Conclusions: The data presented suggest that many, but not all, of the invasive carcinomas presenting after local destructive treatment for CIN resulted from failure to recognise early invasive disease at the time of the initial assessment. The importance of thorough evaluation before undertaking these forms of treatment is emphasised. The use of excisional procedures should further reduce the small risk of invasive carcinoma developing after treatment for CIN.