• Disease-free survival [ Designated as safety issue: No ]
  

• Tolerability [ Designated as safety issue: Yes ]
  
• Quality of life [ Designated as safety issue: No ]
  

OBJECTIVES:

• Compare the disease-free survival of patients with completely resected stage IIB or III colon cancer treated with adjuvant chronomodulated vs standard schedule fluorouracil and leucovorin calcium with or without carboplatin.
• Compare the overall survival of patients treated with these regimens.
• Compare the toxicity of these regimens in these patients.
• Compare the quality of life of patients treated with these regimens.
• Determine the dose intensities of fluorouracil and carboplatin in these patients.

OUTLINE: This is a randomized, multicenter study. Patients are stratified according to participating center and disease stage (IIB vs III). Patients are randomized to 1 of 4 treatment arms.

• Arm I (standard schedule): Patients receive fluorouracil (5-FU) IV continuously and leucovorin calcium (CF) IV on days 1 and 2.
• Arm II (standard + carboplatin schedule): Patients receive 5-FU and CF as in arm I plus carboplatin IV on day 1.
• Arm III (chronomodulated schedule): Patients receive 5-FU IV continuously and CF IV continuously on days 1-4.
• Arm IV (chronomodulated + carboplatin schedule): Patients receive 5-FU and CF as in arm III plus carboplatin IV continuously on days 1-4.

Quality of life is assessed.

Treatment in all arms repeats every 14 days for up to 9 courses in the absence of disease progression or unacceptable toxicity.

PROJECTED ACCRUAL: A total of 660-800 patients will be accrued for this study.

DISEASE CHARACTERISTICS:

• Histologically confirmed adenocarcinoma of the colon

  • Stage IIB or III (Dukes stage B2 or C)
  • Complete curative resection performed within the past 7 weeks (negative margins)
  • No local or regional relapsed disease
• Tumor more than 15 cm above the anal margin
• Carcinoembryonic antigen less than 5 ng/mL (after surgery)
• No rectal cancer
• No metastatic disease

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• ECOG 0-1 OR
• Karnofsky 60-100%

Life expectancy

• Not specified

Hematopoietic

• Neutrophil count at least 2,000/mm3
• Platelet count at least 100,000/mm3

Hepatic

• Bilirubin no greater than 1.5 times upper limit of normal (ULN)
• SGOT and SGPT no greater than 5 times ULN

Renal

• Creatinine no greater than 1.5 times ULN

Cardiovascular

• No serious coronary disease

Other

• Not pregnant
• Fertile patients must use effective contraception
• No concurrent infectious disease
• No other malignancy except adequately treated basal cell skin cancer or carcinoma in situ of the cervix

PRIOR CONCURRENT THERAPY:

Biologic therapy

• No prior immunotherapy

Chemotherapy

• No prior chemotherapy

Endocrine therapy

• Not specified

Radiotherapy

• No prior radiotherapy (before or after surgery)

Surgery

• See Disease Characteristics

Other

• No concurrent participation in another clinical trial