Number of cervical biopsies and sensitivity of colposcopy

OBJECTIVE: To examine the influence that type of medical training and number of biopsies have on sensitivity of colposcopically guided biopsies. METHODS: Among 408 women with an adequate enrollment colposcopy and a diagnosis of cervical intraepithelial neoplasia (CIN) 3 or cancer (CIN 3+) over 2 years in the Atypical Squamous Cells of Undetermined Significance/Low-Grade Squamous Intraepithelial Lesions (ASCUS-LSIL) Triage Study, we evaluated factors influencing the sensitivity of the enrollment colposcopic procedure. We used contingency table analysis to examine confounding variables and chi(2) tests to ascertain statistical significance. RESULTS: Overall, 69.9% of women with a cumulative diagnosis of CIN 3+ had a "true-positive" enrollment colposcopically guided biopsy result of CIN 2 or worse (CIN 2+), the threshold that would trigger excisional therapy. The sensitivity of the procedure did not vary significantly by type of colposcopist. However, the sensitivity was significantly greater when the colposcopists took two or more biopsies instead of one (P <.01), a pattern observed across all types of colposcopists. Independent of the severity of the colposcopic impression, the frequency with which colposcopists took two or more biopsies instead of one varied (in descending order) from nurse practitioners to general gynecologists to gynecologic oncology fellows to gynecologic oncologists (P <.01). CONCLUSION: Colposcopy with guided biopsy or biopsies detects approximately two thirds of CIN 3+. Although the sensitivity of the procedure does not differ significantly by type of medical training, it is greater when two or more biopsies are taken.