Infrared Coagulator Ablation or Observation in Preventing Anal Cancer in HIV-Positive Patients With Anal Neoplasia

DISEASE CHARACTERISTICS: * Diagnosis of high-grade anal intraepithelial neoplasia (AIN) meeting the following: * AIN2 and/or AIN3 confirmed by biopsy ≥ 2 weeks to ≤ 60 days before enrollment * 1-3 lesions with each lesion ≤ 15 mm in diameter * At least one high-grade AIN lesion is still visible at study entry * HIV-infection documented by federally approved, licensed HIV-test in conjunction with screening test (e.g., ELISA, western blot, or other test) * HIV-infection, based on prior ELISA and western blot assays, recorded and documented by another physician, allowed provided patient undergoes an approved antibody test to confirm diagnosis * Patients on concurrent anti-retroviral therapy with a history of HIV-positivity based on an approved antibody test allowed * Detectable plasma HIV-1 RNA also allowed * No perianal AIN, perianal condyloma, or lower vulvar intraepithelial neoplasia or condyloma requiring treatment PATIENT CHARACTERISTICS: * Karnofsky performance status 70-100% * Life expectancy ≥ 2 years * CD4 count ≥ 200/mm³ * ANC \> 750/mm³ * Platelet count ≥ 75,000/mm³ * Hemoglobin ≥ 9.0 g/dL * INR and aPTT normal * Negative pregnancy test * Fertile patients must use effective contraception * Female patients must have undergone cervical pap smear (if having a cervix) and gynecologic evaluation within the past 12 months * Must be capable of complying with the requirements of this protocol * Concurrent HPV-related disease allowed * No history of anal cance…