Radiation Therapy With Capecitabine in Rectal Cancer

• Objectives:
• In patients with locally advanced rectal cancer treated with preoperative radiation and capecitabine chemotherapy to estimate:
• a. the pathologic complete response rate
• b. the clinical response rate
• c. the proportion of patients converted to sphincter sparing surgery
• clinical response rate [ Time Frame: 2 cycles ]
• d. The quantitative and qualitative toxicities of the treatment approach
• e. The relationship of intratumoral levels of thymidylate synthase, dipyrimidine dehydrogenase and thymidine phosphorylase determined immunohistochemically to response

• Objectives:
• In patients with locally advanced rectal cancer treated with preoperative radiation and capecitabine chemotherapy to estimate:
• a. the pathologic complete response rate
• b. the clinical response rate
• c. the proportion of patients converted to sphincter sparing surgery
• d. The quantitative and qualitative toxicities of the treatment approach
• e. The relationship of intratumoral levels of thymidylate synthase, dipyrimidine dehydrogenase and thymidine phosphorylase determined immunohistochemically to response

This study will use an experimental combination of treatment with the drug Capecitabine and radiation therapy prior to an operation for removal of the patient's tumor. The drug Capecitabine is an oral form of a drug called 5-FU which has been widely used to treat rectal cancer.

This is a phase II clinical trial, which means that the physician will be studying the reactions of the patient's body and tumor to treatment with Capecitabine and radiation therapy. The purpose of this study is to see if the tumor responds to this treatment and to determine how long the response lasts. The study also will see what kind of side effects this experimental treatment causes and see how often these side effects occur.

Preliminary human studies using Capecitabine and radiation therapy have produced encouraging results with acceptable side effects.

• Drug: Capecitabine
• Procedure: Radiation
• Procedure: Surgery

Eligibility Criteria

1. Histologic confirmation of adenocarcinoma of the rectum.
2. The lesion must be located in the rectum. For purposes of this study, the lesion must be within 12 cm of the anus as measured by sigmoidoscopy.
3. Patients must have indication of a locally advanced lesion defined for this study as tumor through the bowel wall (> T3) or involving regional lymph nodes (>N1). Clinical stage determination may be made by physical examination (for T4 lesions only), endoscopic ultrasound or CT scan of pelvis.
4. Patients with metastatic disease are eligible provided operative intervention on primary site is anticipated.
5. Patients must have adequate organ function defined as pretreatment leukocyte count > 3,000/ul, platelet count > 100,000/ul, serum creatinine < 2.0 mg/dl, serum bilirubin < 2 mg/dl. Note: Capecitabine is contraindicated in patients with severe renal impairment (creatinine clearance < 30 ml/min). In patients with calculated creatinine clearance of 30-50 ml/min capecitabine will begin at (-)1 level dose reduction (see section 6.3)
6. Patients must be at least 18 years of age and have a Zubrod performance status of < 2 (see appendix 1.)
7. Patients must be informed of the investigational nature of this study and provide written informed consent in accordance with institutional and federal guidelines prior to the initiation of therapy.

Exclusion Criteria:

1. Patients may not have received previous pelvic irradiation for any indication, or previous chemotherapy for cancer therapy within the preceding 6 months.
2. Patients must have no other serious medical or psychiatric illness that would limit the ability of the patient to receive protocol therapy or provide informed consent.
3. Pregnant or lactating women may not participate. Women/men of reproductive potential must agree to use an effective contraceptive method.
4. Patients with lack of physical integrity of the upper gastrointestinal tract, inability to swallow tablets or those who have malabsorption syndrome are not eligible.