Natural history of cervical human papillomavirus lesions does not substantiate the biologic relevance of the Bethesda System.

The newly introduced Bethesda System proposes to replace the terms dysplasia, carcinoma in situ (CIS), or cervical intraepithelial neoplasia (CIN) with two terms, low-grade squamous intraepithelial lesion (SIL) or high-grade SIL. We tested the biologic relevance of the Bethesda System (ie, its ability to establish a close correlation between biologic behavior and the different grades of lesions) in a series of 528 women with genital human papillomavirus (HPV)-associated precancerous lesions prospectively followed for 10 years. The cervical biopsies were reclassified as either low-grade or high-grade SIL, and the data obtained by colposcopy, Papanicolaou smear, and HPV typing, as well as the biological behavior of the lesions, were analyzed in these two groups. Altogether, 77.4% (376 of 486) of the lesions were classified as low-grade SIL lesions; the rest (22.6%) belonged to the high-grade SIL category. In the low-grade SIL category, 46.8% of the women were 24 years old or younger, as compared with 37.3% in the high-grade SIL group. The colposcopic appearance was normal significantly more frequently in the low-grade SIL lesions (22.1%) than in the high-grade category (8.5%) (P less than .001). A single Papanicolaou smear was inadequate to distinguish between low-grade and high-grade SIL, as evidenced by almost identical distributions of Papanicolaou smear class I and II cells in both categories. Noteworthy was the discovery of normal Papanicolaou smears in 8.2% of the high-grade SIL lesions.(ABSTRACT TRUNCATED AT 250 WORDS)