THE EFFICACY OF THE THIN PREP PAP TEST VERSUS CONVENTIONAL MEANS OF CERVICAL CANCER SCREENING IN A SMALL CLINICAL SETTING

Christopher M. Rooney M.D., Michael P. Hopkins M.D.

   Objectives: To compare the Thin Prep PAP preparation to the conventional Papanicolaou smear in a Midwest clinic population to determine if Thin Prep detected more dysplasia and less atypical squamous cells of undetermined significance (ASCUS).

   Materials and Methods: A prospective, matched-pair study was performed from October 1, 2001 through April 30, 2002 in the Obstetrics and Gynecology Clinic at Aultman Hospital in Canton, Ohio. One thousand women were enrolled in the study. Each patient had a Thin Prep and conventional smear performed. Separate cytotechnologists then interpreted the smears without having access to the other preparation. A single Pathologist then reviewed all abnormal results. The McNemar test of paired proportions was then used to analyze the data with a statistical power of 0.8.

   Results: A total of 2,000 cytological preparations were evaluated. When comparing the 1,000 conventional smears (C) to the 1,000 Thin Prep PAP preparations (TP), the following results were obtained: within normal limits: 708 (C), 690 (TP), p=0.055; ASCUS: 54 (C), 66 (TP), p=0.201; low-grade squamous intraepithelial lesion (LGSIL): 171 (C), 77 (TP), p<0.05; high-grade squamous intraepithelial lesion (HGSIL): 7 (C), 35 (TP), p<0.05; atypical glandular cells of undetermined significance (AGUS): 9 (C), 9 (TP), p=1.000; and carcinoma in situ: 2 (C), 0 (TP).

   Conclusions: The Thin Prep PAP preparation identified more HGSIL but far less LGSIL than the conventional Papanicolaou smear with similar detection rates of ASCUS and AGUS.