Anal cancer precursor lesions in HIV-positive and HIV-negative patients seen at a tertiary health institution in Brazil.

PURPOSE

To investigate the prevalence of anal squamous intraepithelial lesions (ASIL) or anal cancer in patients attended at the Tropical Medicine Foundation of Amazonas.

METHODS

344 patients consecutively attended at the institution, in 2007/2008, were distributed in the following strata according to presence/abscense of at risk conditions for anal cancer: Group 1 - HIV-positive men-who-have-sex-with-men (101); Group 2 - HIV-positive females (49); Group 3 - patients without any at risk condition for anal cancer (53); Group 4 - HIV-positive heterosexual men (38); Group 5 - HIV-negative patients, without anoreceptive sexual habits, but with other at risk conditions for anal cancer (45); Group 6 - HIV-negative men-who-have-sex-with-men (26); and Group 7 - HIV-negative anoreceptive females (32). The histopathological results of biopsies guided by high-resolution anoscopy were analyzed by frequentist and bayesian statistics in order to calculate the point-prevalence of ASIL/cancer and observe any eventual preponderance of one group over the other.

RESULTS

The point-prevalence of ASIL for all the patients studied was 93/344 (27%), the difference between HIV-positive and negative patients being statistically significant (38.3% versus 13.5%; p < 0.0001). The prevalence of ASIL for each one of the groups studied was: Group 1 = 49.5%, Group 2 = 28.6%, Group 3 = 3.8%, Group 4 = 21.1%, Group 5 = 11.1%, Group 6 = 30.8% and Group 7 = 18.8%. Standard residual analysis demonstrated that ASIL was significantly prevalent in patients of Group 1 and high-grade ASIL in patients of Group 2. The odds for ASIL of Group 1 was significantly higher in comparison to Groups 2, 3, 4, 5 and 7 (p < 0.03). The odds for ASIL of Groups 2, 4 and 6 were significantly higher in comparison to Group 3 (p < 0.03).

CONCLUSIONS

In the patients studied, ASIL (low and/or high-grade) tended to be significantly more prevalent in HIV-positive patients. Nonetheless, HIV-negative anoreceptive patients also presented great probability to have anal cancer precursor lesions, mainly those of the male gender.