Statins are widely used as lipid-lowering agents to lower cardiovascular risk with a favorable safety profile. In our recent in vitro study, the addition of simvastatin to chemoradiotherapy with 5-FU showed synergistic anticancer effect in various colon cancer cells (unpublished data). So we planned this study to investigate the synergistic effect of simvastatin combined with capecitabine and radiotherapy in locally advanced rectal cancer patients.

1. Primary Objective: pathologic complete response rate

2. Secondary Objectives:

   1. rate of sphincter-sparing surgical procedure
   2. rate of R0 resection
   3. disease-free survival
   4. overall survival
   5. pattern of failure
   6. safety and toxicity
   7. lipid lowering effect of simvastatin

Inclusion Criteria:

• Histologically-confirmed adenocarcinoma of rectum
• AJCC/UICC clinical stages of cT3-4 or cN+
• age ≥ 20 years
• ECOG performance status 0-1
• No prior chemotherapy and radiotherapy
• Adequate major organ functions as following:
• Written informed consent
• Willing and able to comply the protocol

Exclusion Criteria:

• Prior statins therapy within 1-year from the date of study entry
• Uncontrolled or severe cardiovascular disease :

New York Heart Association class III or IV heart disease Unstable angina or myocardial infarction within the past 6 months History of significant ventricular arrhythmia requiring medication with antiarrhythmics or significant conduction system abnormality.

• Past or current history (within the last 5 years prior to treatment start) of other malignancies except rectal cancer (Patients with curatively treated basal and squamous cell carcinoma of the skin or in situ carcinoma of the cervix are eligible)
• Uncontrolled systemic illness such as DM, hypertension, hypothyroidism and infection
• Pregnant nursing women (women of reproductive potential have to agree to use an effective contraceptive method)
• Patients with CPK > 5 X ULN at baseline
• Concomitant use with clarithromycin, erythromycin, itraconazole, ketoconazole, nefazodone, telithromycin, gemfibrozil, cyclosporine, danazol, amiodarone, verapamil