Anal cancer and its precursors in HIV-positive patients: perspectives and management

Anal cancer is an increasing problem among HIV-infected persons. Although patients are living longer and with better quality of life because of treatment with HAART, they remain at risk for invasive anal cancer and its precursor, anal HSIL. Given the substantial numbers of patients with anal HSIL, further studies need to be done to determine the efficacy and optimal mode of treatment of HSIL, to define the optimal method for screening patients at risk, to define the best way to follow up patients with documented HSIL to ensure early detection, to define prognostic factors for progression to invasive cancer, and to determine the progression rate of HSIL to invasive cancer. Although patients with good functional status and immunologic function seem to do relatively well with standard CMT for anal cancer, there are less fortunate patients who experience substantial morbidity from therapy and have a poorer outcome. It is difficult to draw definitive conclusions about the therapy of HIV-positive patients with anal cancer based on the available literature because of the retrospective nature of the analyses, the small number of patients, and the heterogeneity of the patients reported with regard to tumor size, pretreatment immunologic status, and the variety of treatments received by patients in some series. Identifying patients who develop invasive anal cancer as early as possible will improve results to some degree, but prospective, controlled, multi-institutional trials evaluating the treatment of anal cancer in HIV-infected persons are required to accurately define ways to improve outcome with less morbidity. The results of ongoing therapeutic HPV vaccine trials are eagerly awaited. Improvement may come by the following, determining ways to more accurately stage patients, such as endoanal ultrasound, sentinel lymph node sampling, or positron emission tomography scans; defining the role of cisplatin and whether it is indeed less toxic and equally or more effective; consideration of continuous protracted infusion of low-dose 5-FU; the optimum use of growth factors; and an evaluation of the role of conformal radiotherapy or the use of radio-protectants, such as amifostine. Meanwhile, the best way to treat anal cancer in HIV-infected persons may be to prevent it from occurring by screening persons at risk and treating HSIL, or at a minimum, following up patients carefully and detecting cancers, if they occur, at the earliest possible time.