DISEASE CHARACTERISTICS:

• Histologically confirmed basal cell carcinoma (BCC)

  • At least 5 prior BCCs AND
  • At least 4 BCCs within the past year

• Meets diagnostic criteria for basal cell nevus syndrome (BCNS)

  • Any 1 of the following:

    • More than 2 BCCs or 1 before age 20
    • Histologically confirmed odontogenic keratocysts of the jaw
    • 3 or more palmar and/or plantar pits
    • Bilamellar calcification of the falx cerebri (if less than 20 years of age)
    • Fused, bifid, or markedly splayed ribs
    • First degree relative with BCNS
    • PTC gene mutation in normal tissue OR

  • Any 2 of the following:

    • Macrocephaly determined after adjustment for height
    • Congenital malformations (e.g., cleft lip or palate, frontal bossing, "coarse face", or moderate or severe hypertelorism)
    • Skeletal abnormalities (e.g., Sprengel deformity, marked pectus deformity, or marked syndactyly of the digits)
    • Radiological abnormalities (e.g., bridging of the sella turcica, vertebral anomalies, modeling defects of the hands and feet, or flame-shaped lucencies of the hands or feet)
    • Ovarian fibroma
    • Medulloblastoma

PATIENT CHARACTERISTICS:

Age:

• 18 to 75

Performance status:

• Not specified

Life expectancy:

• Not specified

Hematopoietic:

• WBC greater than 3,000/mm^3
• Platelet count greater than 125,000/mm^3
• Hemoglobin greater than 12.0 g/dL (women)
• Hemoglobin greater than 13.0 g/dL (men)
• No significant coagulation defect

Hepatic:

• Bilirubin normal
• ALT/AST no greater than 1.5 times upper limit of normal (ULN)
• No chronic or acute hepatic disorder

Renal:

• Creatinine no greater than 1.5 times ULN
• BUN normal
• Electrolytes within normal
• No chronic or acute renal disorder

Cardiovascular:

• No congestive heart failure

Gastrointestinal:

• No active gastrointestinal disease
• No inflammatory bowel disease
• No chronic or acute pancreatic disorder
• No history of gastrointestinal ulceration allowed except with permission of primary care physician
• No esophageal, gastric, pyloric channel, or duodenal ulceration within the past 30 days
• Stool hematest normal

Other:

• No prior invasive malignancy within the past 5 years except nonmelanoma skin cancer, stage I cervical cancer, stage 0 chronic lymphoblastic leukemia, or medulloblastoma
• No hypersensitivity to COX-2 inhibitors, nonsteroidal anti-inflammatory drugs (NSAIDs), salicylates, or sulfonamides
• No other condition that would preclude study involvement
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• At least 2 weeks since prior topical agents as chemoprevention
• At least 1 year since other prior chemotherapy

Endocrine therapy:

• At least 1 month since prior oral or IV corticosteroids
• At least 6 months since prior inhaled corticosteroid use for longer than 4 weeks
• At least 2 weeks since prior topical glucocorticoids
• No concurrent topical glucocorticoids
• Concurrent oral and IV corticosteroid use of less than 2 weeks within 6 months allowed
• Concurrent inhaled corticosteroid use of less than 4 weeks within 6 months allowed

Radiotherapy:

• Not specified

Surgery:

• Not specified

Other:

• At least 2 weeks since prior topical retinoids or alpha-hydroxy acids (e.g., glycolic acid or lactic acid)
• At least 2 weeks since prior topical medications
• At least 30 days since prior investigational agents
• At least 2 months since prior NSAIDs given more than 3 times/week
• At least 2 months since prior aspirin dose of more than 100 mg/day given more than 3 times/week
• At least 6 months since prior oral retinoids
• No concurrent chronic NSAIDs (more than 3 times per week for at least 2 weeks)
• No concurrent aspirin dose of more than 100 mg/day
• No concurrent topical medications
• No concurrent fluconazole
• No concurrent lithium
• No concurrent retinoids (including topical administration) or alpha-hydroxy acids
• No other concurrent investigational agents