High prevalence of high grade squamous intraepithelial lesions and microinvasive carcinoma in women with a cytologic diagnosis of low grade squamous intraepithelial lesions.

OBJECTIVE

To evaluate the histologic nature of low grade intraepithelial lesion (LSIL) in a region with a high prevalence of invasive cervical carcinoma and to propose a management protocol.

STUDY DESIGN

Comparing the follow-up of 877 women with LSIL during a 43-month period, taking into consideration the histologic nature determined by colposcopic biopsy, endocervical curettage, conization or hysterectomy as the final pathologic diagnosis.

RESULTS

During the study period, from July 1994 to February 1998, a total of 128,925 Pap smears were performed at our institute, with 877 (0.68%) diagnosed as LSIL. Among these, 722 women with CIN1-SIL and 32 with human papillomavirus-related changes (HPV-SIL) were enrolled in the study. Of the 543 women with CIN 1/squamous intraepithelial lesion, 145 (27%) cases of high grade squamous intraepithelial lesion were disclosed histologically, as were 16 (3%) cases of microinvasion. Among those followed at an interval of three months with a Pap smear alone, the persistence rate was 46.8%, while the regression rate was 40%. Thirty-two women with HPV/SIL underwent histologic evaluation, revealing 18% CIN 2/3 with no microinvasion.

CONCLUSION

A high percentage of CIN 2/3 as well as microinvasive lesions will go unnoticed in the absence of colposcopic evaluation.