Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed carcinoma of the anal canal, including any of the following
subtypes:

- Squamous cell

- Basaloid

- Cloacogenic

- Primary invasive disease

- T2-4, N0-3 disease

- Clinically positive small inguinal nodes (i.e., < 1 cm in size) must be
confirmed by biopsy (preferably fine-needle aspiration) within the past 6 weeks

- Biopsy is not required for enlarged inguinal, perirectal, or pelvic nodes on
exam or CT scan that are found to be ≥ 1.0 cm and are considered to be
clinically positive

PATIENT CHARACTERISTICS:

- Zubrod performance status 0-1

- Hemoglobin ≥ 8.0 g/dL (transfusion or other intervention allowed)

- ALT and AST < 3 times upper limit of normal

- Absolute neutrophil count ≥ 1,800/mm³

- Serum creatinine ≤ 1.5 mg/dL

- Platelet count ≥ 100,000/mm³

- Bilirubin < 1.4 mg/dL

- WBC ≥ 3,000/mm³

- INR ≤ 1.5

- No known AIDS

- HIV-positive patients without AIDS are eligible

- HIV test required for patients with clinical suspicion of AIDS

- No other invasive malignancy within the past 3 years except for nonmelanomatous skin
cancer

- No severe, active comorbidity, defined as any of the following:

- Unstable angina and/or congestive heart failure requiring hospitalization within
the past 6 months

- Transmural myocardial infarction within the past 6 months

- Acute bacterial or fungal infection requiring IV antibiotics

- Chronic obstructive pulmonary disease exacerbation or other respiratory illness
requiring hospitalization or precluding study treatment

- Hepatic insufficiency resulting in clinical jaundice and/or coagulation defects

- Uncontrolled diabetes mellitus, uncompensated heart disease, and/or uncontrolled
high blood pressure, that in the opinion of the patient's treating physician,
requires an immediate change in management

- Patients may be eligible if appropriate changes in management have resulted
in adequate control of the above mentioned conditions

- Other immunocompromised status (e.g., organ transplantation or chronic
glucocorticoid use)

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- No prior radiation therapy to the pelvis that would result in overlap of radiation
therapy fields

- No prior systemic chemotherapy for cancer of the anus

- No prior surgery for cancer of the anus that removed all macroscopic anal cancer

- No concurrent sargramostim (GM-CSF)

- No concurrent amifostine