Inclusion Criteria:

- Histologically confirmed colorectal cancer

- Measurable radiographic evidence of colorectal cancer

- Patients with unresected metastases from colorectal cancer; patients may be either
untreated with chemotherapy or currently receiving first-line 5-FU based chemotherapy
(folinic acid-fluorouracil-irinotecan [FOLFIRI], capecitabine-irinotecan [CAPIRI],
fluorouracil-leucovorin calcium-oxaliplatin [FOLFOX], or capecitabine-oxaliplatin
[CAPOX] with or without bevacizumab) within 6 months of study entry date with at
least stable disease radiographically; patients who received prior adjuvant
chemotherapy with 5-FU, capecitabine, or FOLFOX are eligible if adjuvant therapy was
completed greater than 6 months ago

- History of histological confirmation for recurrent disease, or if recurrent disease
is not readily accessible to biopsy, must have two consecutive carcinoembryonic
antigen (CEA) or cancer antigen (CA) 19-9 increases, or positron emission tomography
(PET) avidity

- Men and women from all ethnic and racial groups

- Eastern Cooperative Oncology Group (ECOG) performance status =< 1

- Total bilirubin =< 1.5 x the institutional upper-normal limit (IUNL)

- Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase [SGOT])
and/or alanine aminotransferase (ALT) (serum glutamic pyruvate transaminase [SGPT])
=< 2.5 x IUNL

- Alkaline phosphatase =< 2.5 x IUNL

- Leukocytes >= 3,000/uL

- Absolute neutrophil count >= 1,000/uL

- Platelets >= 100,000/uL

- Women of childbearing age and all men must agree to use adequate contraception
(hormonal or barrier method of birth control) prior to study entry and for the
duration of study participation

- Negative urine pregnancy test for women of childbearing age

- Must have the ability to understand and the willingness to provide a written informed
consent to participate in the study

Exclusion Criteria:

- History of allergies to sulfonamide, aspirin, any nonsteroidal anti inflammatory
drugs (NSAIDS), 5-FU or celecoxib

- Prior 5-FU-based adjuvant chemotherapy less than 6 months prior to study entry and
any residual neuropathy > grade 2

- Any regular use of cyclooxygenase-2 (COX-2) inhibitors as defined by 2-3 times per
week

- Use of aspirin is NOT an exclusion criteria as long as the daily dose does not exceed
325 mg daily; initiation of ADAPT therapy requires patient to discontinue aspirin for
18 months

- Pregnant or lactating women

- History of significant neurologic or psychiatric disorders, including dementia or
seizures that would impede consent, treatment, or follow up

- Any serious illness or medical condition that could affect participation on trial

- Any uncontrolled congestive heart failure New York Heart Association class III or IV

- Any uncontrolled hypertension, arrhythmia, or active angina pectoris

- Any history of major myocardial infarction, stroke or transient ischemic attack
(TIA); minor acute myocardial infarction (AMI) and patients who have had cardiac
bypass free of symptoms for at least 2 years may be eligible at the discretion of the
study chair

- Serious uncontrolled active infection

- Patients with creatinine clearance: < 50 mL/min are excluded from this protocol;
capecitabine is contraindicated in severe renal impairment (clearance < 40 mL/min)

- Inability to swallow oral medications or any medical conditions that may affect
intestinal absorption of the study agent or inability to comply with oral medication

- History of active peptic ulcer disease or major upper gastrointestinal (GI) bleed <
12 months; history of GI bleeding from the colorectal cancer primary is not an
exclusion criteria

- Use of warfarin is not allowed; patient is recommended to switch to low molecular
weight heparin (LMWH) before participating in this study

- Patients with any history of brain or bone metastasis or who have develop progressive
disease on first line 5-FU based therapy

- Current use of steroid medication

- Patients with an obstructive synchronous colorectal tumor requiring up-front surgery
or chemoradiation

- Patients with partial or complete bowel obstruction due to abdominal carcinomatosis