A three year follow-up of low grade squamous intraepithelial lesions: Persistence of lesions is significantly influenced by the presence of high risk papillomaviruses

A cohort of 921 patients with low-grade squamous intraepithelial lesions (LG-SILs) was studied every six months for a period of 3 years by cytology and colposcopy. Regression of the initial cell injury to a normal cytology was observed in 585/921 cases (63.5%), while cytological abnormalities were still present at the same or higher grade, after three years, in 336/921 cases (36.5%). A sample of 122 Papanicolaou (Pap}stained cervical smears from the cohort of 921 LG-SILs were processed by an in situ hybridization (ISH) assay to search for the presence of DNA of human papillomaviruses (HPVs) considered at high oncogenic risk: 16/18 and 31/35/51. HPV DNA typization was positive for 47/122 lesions (38.5%). Among these 47 lesions associated with high risk HPV DNA, 12 (25.5%) healed and 35 (74.5%) persisted. Of the 75 HPV DNA negative lesions, 46 (61.3%) healed and 29 (38.7%) persisted. The results are discussed in order to define a correct protocol of LG-SIL follow-up.