Chemotherapy Plus Radiation Therapy in Treating Patients With Unresectable, Residual, or Recurrent Colorectal Cancer

OBJECTIVES: I. Determine the maximum tolerated dose of oral capecitabine administered in
combination with pelvic radiotherapy in patients with unresectable, residual, or locally
recurrent cancer localized in the pelvis. II. Determine the tolerance of this regimen in
these patients. III. Determine the preliminary evidence of therapeutic acticivity of this
regimen in these patients.

OUTLINE: This is a dose-escalation study of capecitabine. Patients receive oral capecitabine
twice a day 7 days a week for 6 weeks with concurrent radiotherapy. Radiotherapy is
initiated on the same day as the initiation of capecitabine and is administered 5 days a
week for 5.5-6 weeks. Cohorts of 3-6 patients receive escalating doses of capecitabine until
the maximum tolerated dose (MTD) is reached. The MTD is defined as the dose at which 2 of 3
or 6 patients experience dose-limiting toxicity. Patients are followed every 3 months for 2
years and then every 6 months for 1 year.

PROJECTED ACCRUAL: A maximum of 51 patients will be accrued for this study.

DISEASE CHARACTERISTICS: Histologically confirmed carcinoma located in the pelvis that is
unresectable, incompletely resected, or locally recurrent Must be biopsy-proven or have
radiological progression All disease must be encompassable within standard pelvic
radiotherapy fields No evidence of metastatic disease outside of the planned radiotherapy
field

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy:
Not specified Hematopoietic: WBC at least 3,500/mm3 Platelet count at least 100,000/mm3
Hepatic: Not specified Renal: Creatinine clearance at least 30 mL/min Other: Must maintain
adequate oral nutrition (i.e., at least 1200 calories estimated intake per day) No
significant infection or other concurrent medical condition that would preclude study No
significant nausea or vomiting No malabsorption secondary to short-gut syndrome, Crohn's
disease, or sprue No patients with more than 6 bowel movements per day or baseline no
greater than grade 3 diarrhea for patients with colostomy Not pregnant or nursing Negative
pregnancy test Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No prior
chemotherapy for metastatic cancer At least 6 months since prior adjuvant chemotherapy
Endocrine therapy: Not specified Radiotherapy: See Disease Characteristics No prior
radiotherapy Surgery: At least 21 days since prior laparotomy or laparoscopic procedure
with or without resection Other: No concurrent sorivudine or chemically related analogues
(e.g., brivudine)