Summary
This phase III trial studies imiquimod or fluorouracil to see how well they work compared to observation in treating patients with high-grade anal squamous skin lesions who are human immunodeficiency virus (HIV)-positive. Biological therapies, such as imiquimod, may stimulate the immune system in different ways and stop tumor cells from growing. Drugs used in chemotherapy, such as fluorouracil, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. It is not yet known whether imiquimod or fluorouracil is more effective than observation in treating high-grade anal squamous skin lesions.