DISEASE CHARACTERISTICS:

• Histologically proven superficial transitional cell carcinoma of the bladder at high risk for recurrence, meeting 1 of the following staging criteria:

  • Stage Ta (grade 3 OR multifocal OR at least 2 occurrences, including current tumor, within the past 12 months)
  • Stage T1 (any grade)
  • Stage Tis
• Patients with Ta or T1 lesions must have undergone complete transurethral resection of bladder tumor within the past 9 months
• No carcinoma involving the prostatic urethra or upper urinary tract

• Must have received the following prior to randomization:

  • Induction course of BCG comprising 6 weekly intravesical doses (at least 4 doses if BCG intolerant)

    • Additional induction courses of BCG allowed
  • Maintenance course of BCG comprising 3 weekly doses (at least 1 dose if BCG intolerant)
  • No evidence of disease by cystoscopy (with or without biopsy) and bladder cytology prior to initiation of maintenance BCG
  • Concurrent interferon allowed

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• Zubrod 0-2 OR
• ECOG 0-2

Life expectancy:

• Not specified

Hematopoietic:

• WBC at least 3,000/mm^3
• Hemoglobin at least lower limit of normal
• Platelet count at least 125,000/mm^3
• No significant bleeding disorder

Hepatic:

• Bilirubin no greater than 1.5 times upper limit of normal (ULN)
• SGOT and SGPT no greater than 1.5 times ULN
• No chronic or acute hepatic disorder

Renal:

• Creatinine no greater than 1.5 times ULN
• No chronic or acute renal disorder
• Normal kidneys and ureters on imaging study within the past 9 months

Gastrointestinal:

• No active inflammatory bowel disease (e.g., Crohn's disease or ulcerative colitis)
• No active pancreatitis
• No esophageal, gastric, pyloric channel, or duodenal ulceration that was diagnosed or treated within the past 30 days

Cardiovascular

• No history of cardiovascular disease, including any of the following conditions:

  • Myocardial infarction
  • Angina
  • Congestive heart failure
  • Stroke

Other:

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• No other medical or psychological condition that would preclude study participation
• No hypersensitivity or adverse reactions to sulfonamides, cyclooxygenase (COX)-2 inhibitors, salicylates, or other NSAIDs

• No other prior malignancy within the past 5 years except:

  • Nonmelanomatous skin cancer cured by excision
  • Carcinoma in situ of the cervix
  • Stage 0 chronic lymphocytic leukemia
  • Other malignancy for which patient has no current evidence of disease, has received no therapy within the past 6 months, has no concurrent or planned therapy, and has an expected disease-free survival of at least 5 years

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• See Disease Characteristics
• No concurrent immunotherapy

Chemotherapy:

• No concurrent chemotherapy

Endocrine therapy:

• No concurrent oral or IV corticosteroids for more than 2 consecutive weeks or orally inhaled corticosteroids for more than 4 consecutive weeks during any 6 month period of the study

  • Chronic nasally inhaled steroids allowed provided patient agrees to use mometasone or, in countries where mometasone is not available, fluticasone
• No other concurrent hormonal therapy except hormone replacement (i.e., estrogen or thyroid hormone replacement)

Radiotherapy:

• No prior pelvic radiotherapy
• No concurrent radiotherapy

Surgery:

• See Disease Characteristics
• No prior angioplasty
• No prior coronary bypass surgery

Other:

• At least 30 days since prior investigational medication
• At least 2 weeks since prior aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) except cardioprotective dose (no greater than 100 mg/day) of aspirin

• No concurrent chronic NSAIDs except oral cardioprotective dose (no greater than 100 mg/day) of aspirin

  • Concurrent chronic use is defined as a frequency of at least 3 times per week for more than 2 consecutive weeks per year
• No other concurrent investigational drug
• No other concurrent systemic therapy
• No concurrent lithium or fluconazole