Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed stage I-IIIB invasive anal canal or perianal (anal margin)
squamous cell carcinoma, including tumors with any of the following nonkeratinizing
histologies:

- Basaloid

- Transitional cell

- Cloacogenic

- Documented HIV infection by 1 of the following:

- Antibody detection

- Culture

- Quantitative assay of plasma HIV RNA

PATIENT CHARACTERISTICS:

- Karnofsky performance status 60-100%

- Absolute neutrophil count ≥ 1,500/mm³

- Platelet count ≥ 100,000/mm³

- Hemoglobin ≥ 10 g/dL (transfusions, epoetin alfa, or myeloid growth factor support
allowed provided blood counts are stable for ≥ 2 weeks prior to study entry)

- Creatinine ≤ 1.5 times upper limit of normal (ULN) OR creatinine clearance > 60
mL/min

- AST and ALT ≤ 3 times ULN

- Bilirubin ≤ 2 times ULN

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- No acute active, serious, uncontrolled opportunistic infection

- No other prior invasive malignancy diagnosed within the past 24 months, excluding in
situ cervical cancer, anal dysplasia or carcinoma in situ, nonmelanoma skin
carcinoma, or Kaposi's sarcoma that has not required systemic chemotherapy within the
past 24 months

- No peripheral neuropathy > grade 1

- No severe or poorly controlled diarrhea

- No medical or psychiatric illness that would preclude study requirements

PRIOR CONCURRENT THERAPY:

- No prior chemotherapy or radiotherapy for this malignancy

- Prior radiotherapy for another condition (e.g., Kaposi's sarcoma) allowed