Human papillomavirus infection and cervical cancer in Brazil: a retrospective study

ABSTRACT

Two hundred and thirty paraffin-embedded biopsies obtained from female cervical lesions were tested for the presence of human papillomavirus (HPV) types 6/11, 16/18 and 31/33/35 DNA using non-isotopic in situ hybridization. Specimens were classified according to the Bethesda System in low grade squamous intraepithelial lesion (LSIL), high grade SIL (HSIL) and squamous cell carcinoma (SCC). HPV prevalence ranged from 92.5 per cent in LSIL to 68.5 per cent in SCC. Benign types were prevalent in LSILs while oncogenic types infected predominantly HSILs and SCC. HPV infection showed to be age-dependent, but no significant relation to race has been detected. Patients were analyzed through a five-year period 20.7 per cent of the lesions spontaneously regressed while 48.9 per cent persisted and 30.4 per progressed to carcinoma. Patient submitted to treatment showed a 19.4 per cent recurrence rate. High risk types were present in 78.6 per cent (CrudeOR 13.8, P=0.0003) of the progressive lesions, and in 73.7 per cent of the recurrent SILs (COR 19.3, P=0.0000001). Possible co-factors have also been evaluated history of other sexually transmitted diseases showed to be positively related either to progression (Adjusted OR 13.0, P=0.0002) or to recurrence (AOR 17.2, P=0.0002) while oral contraceptive use and tobacco smoking were not significantly related to them (P>0.1). Association of two or more co-factors also proved to be related to both progression and recurrence, indicating that they may interact with HPV infection in order to increase the risk of developing malignant lesions.