Valor da anuscopia com magnificação de imagem no diagnóstico de lesões precursoras do câncer anal em pacientes HIV+ atendidos na Fundação de Medicina Tropical do Amazonas

Abstract

BACKGROUND: The anal cancer incidence, about 1,5% of malignant tumors of the gastrointestinal tract, has increased among men who have sex with men (MSM) which have contracted the human immunodeficiency virus (HIV+), to 70/100.000 people with the same behavior. The development of this cancer is a consequence of the interaction of several factors, among them, human papilomavirus (HPV) infection, immunodepression and anal sex practice. The similarities to the cervical cancer development (low and high grade precursor lesions, which can be early diagnosed) have inspired many studies performed in order to establish guidelines for the detection and treatment of precursor lesions of anal cancer, intending its prevention. The high-resolution anoscopy (HRA) is routinely used in this diagnosis; however, medical literature is even deficient concerning to the role of this diagnostic modality in the detection of precursor lesions of anal cancer. Taking these facts into account, this study has the intention of checking the validity of this test by comparing it to histopathology results of HIV+ patients of the Fundação de Medicina Tropical do Amazonas (FMT-AM). METHODS: The patients included (128) underwent a proctologic examination with the collection of anal channel cells, and using the Polimerase Chain Reaction (PCR) technique, it was researched the presence of HPV. Afterwards, HRA and topical anal application of Acetic Acid 3% during 2 minutes were performed. The acetowhite areas (AWA) detected were recorded concerning to their localization, classified by their color pattern, focal or coalescent aspect, relief, surface and vascular pattern. Facing the image characteristics of the observed lesions, these were classified into normal, low-grade squamous intraepithelial lesion (LSIL) or high-grade squamous intraepithelial lesion (HSIL) to the development of anal cancer. In addition, biopsies of the AWA were performed under local anesthesia, to undergo histopathologic analysis. RESULTS: Fro The HRA showed sensibility of 90%, specificity of 19,23%, positive predictive value of 41,66%, negative predictive value of 75%, and kappa coefficient of 0,076. Im the analyzed lesions it was found in the HSIL a more frequent visualization of 68% dense AWA, 61% flat, 61% smooth, 83% no-papillary and 70% normal vascular pattern, while in the LSIL they were 66% dense AWA, 68% flatraised or raised, 59% granular, 62% no-papillary and 53% normal vascular pattern. Gender, age, level of education and skin color did not represent associated factors to the development of AW lesions or to anal squamous intra-epithelial lesions (ASIL). The risk factors implied in the anal carcinogenesis were taking these factors into account, there was not statistic significance in the occurrence of AW lesions. Even though, to ASIL, it was demonstrated a relevance between anal sex adepts (p = 0,0493) and the presence of HPV infection (p = 0,006). CONCLUSIONS: The HRA has demonstrated to be sensible, but not specific in the detection of ASIL. In addition, it was not found association between HRA results histopathologic and the presence of HPV anal infection. The prevalence of HPV in the studied population was 79% and the prevalence of ASIL was 39,1%. Based on image data, the relief and surface pattern were able to distinguish between LSIL and HSIL, while the other characteristics did not show relevance.