RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing
so they stop growing or die. Combining more than one drug and combining radiation therapy
with chemotherapy may kill more tumor cells.
PURPOSE: Phase I trial to study the effectiveness of combination chemotherapy consisting of
fluorouracil-uracil and leucovorin plus radiation therapy in treating patients with
colorectal cancer who have undergone surgery to remove the tumor.
OBJECTIVES: I. Determine the maximum tolerated dose and dose-limiting toxicity of
postoperative fluorouracil-uracil plus leucovorin calcium concurrently with radiotherapy in
patients with colorectal cancer. II. Determine the toxicity of this regimen in these
patients. III. Determine the response of tumors in patients with measurable disease treated
with this regimen.
OUTLINE: This is a dose-escalation study of fluorouracil-uracil (UFT). Beginning within 10
weeks after definitive surgery, patients receive oral UFT and oral leucovorin calcium (CF) 3
times a day on days 1-28. Treatment continues every 5 weeks for 2 courses in the absence of
disease progression or unacceptable toxicity. Beginning on day 1 of the second course,
patients undergo radiotherapy to the tumor bed and involved lymph nodes 5 days a week for 5
weeks, followed by boost radiotherapy to the primary tumor bed for 5-16 days. Patients
receive 3 additional courses of UFT plus CF beginning 4 weeks after completion of
radiotherapy or after recovery from the toxic effects of UFT, whichever occurs later.
Patients who have measurable disease with ongoing response after the fifth course receive
additional courses of UFT and CF. Cohorts of 3-6 patients receive escalating doses of UFT
during the second course until the maximum tolerated dose (MTD) is determined. The MTD is
defined as highest dose at which the minority of patients experience dose-limiting toxicity.
Patients are followed every 3 months for 1 year and then at the discretion of the
PROJECTED ACCRUAL: Approximately 30 patients will be accrued for this study.
DISEASE CHARACTERISTICS: Diagnosis of colorectal cancer for which postoperative
radiotherapy to the pelvis is indicated
PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At
least 3 months Hematopoietic: WBC at least 4,000/mm3 Absolute granulocyte count at least
1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 mg/dL
ALT no greater than 1.25 times upper limit of normal (ULN) (no greater than 5 times ULN if
elevation secondary to malignancy) Alkaline phosphatase no greater than 1.25 times ULN (no
greater than 5 times ULN if elevation secondary to malignancy) Renal: Creatinine normal OR
Creatinine clearance normal or greater than 60 mL/min Other: No medical or psychiatric
condition that would preclude study No prior malignancy except: Appropriately treated
localized epithelial skin or cervical cancer Remote history of other cured malignancy (at
the discretion of the sponsor) Not pregnant or nursing Negative pregnancy test Fertile
patients must use effective contraception
PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent antineoplastic biological
response modifiers Chemotherapy: No prior systemic chemotherapy Endocrine therapy: Not
specified Radiotherapy: See Disease Characteristics No prior radiotherapy to the pelvis
Surgery: See Disease Characteristics Other: No other concurrent investigational drugs No
other concurrent antineoplastic therapy No concurrent halogenated antiviral agent (e.g.,