Using the Cone Biopsy to Compare Colposcopy Clinics in New York and London

Abstract

To assess whether there were significant differences in cytologic and colposcopic assessments associated with conization specimens at a colposcopy clinic in New York compared with a colposcopy clinic in London. A retrospective histopathologic survey of patients evaluated at the Mt. Sinai Hospital Colposcopy Clinic (MSH) in New York City and the Royal Free Hospital Colposcopy Clinic (RFH) in London between January 1, 1997, and December 31, 1998, was reviewed. Study groups included all patients who underwent conization at either clinic. Referral cytologic results, colposcopic findings, and conization histologic results were compared. Two hundred three cases from MSH and 457 cases from RFH were reviewed. Most patients undergoing conization in either clinic were referred with Pap smears suggesting high-grade squamous intraepithelial lesions (MSH, 77%; RFH, 77%). Colposcopic biopsy was performed on all patients at MSH. At RFH, colposcopic-directed punch biopsy was not performed on 35% of the patients who would have been treated regardless of biopsy results. There is a significant difference in the distribution of cone histologic diagnosis between the two clinics (p = .02); there are proportionally more women diagnosed with high-grade disease in RFH than in MSH, where there are more normal and low-grade cone histologic results. According to the kappa coefficients, there is only slight agreement between the Pap smear cytologic results and punch biopsy with the conization histologic results for either clinic (MSH, kappa = 0.13; RFH, kappa = 0.19), with the RFH performing slightly better. This study shows exact agreement between cytologic and final conization diagnosis and colposcopic biopsy and final conization as 47% to 64%. Treatment decisions and outcomes are different between the two clinics, with the RFH clinic performing fewer biopsies and having more procedures yielding high-grade disease. Recommendations regarding changing colposcopic practices could best be made after a prospective study.