Inclusion Criteria

DISEASE CHARACTERISTICS:

- Pathologically confirmed squamous metaplasia or squamous dysplasia of the lungs by
autofluorescence bronchoscopy within the past 5 years

- Must be a current or former smoker

- No evidence of concurrent disease with lung cancer or head and neck cancer

- History of treated lung cancer or head and neck cancer treated with curative
intent allowed, provided that there has been no evidence of disease for > 1 year

PATIENT CHARACTERISTICS:

- ECOG performance status 0-1

- Total granulocyte count > 1,500 x 10^9cells/L

- Platelet count > 100,000 x 10^9cells/L

- Calculated Creatinine clearance > 60 mL/min (using the Cockcroft-Gault formula)

- Calcium concentration 50-300 mg/24 hours

- Total bilirubin 0.2-1.3 mg%

- ALT/AST ≤ 2.5 times upper limit of normal (ULN)

- Alkaline phosphatase ≤ 2.5 times ULN

- Albumin ≥ 2.5 g/dL

- Ionized serum calcium normal (1.19-1.29 mmol/L)

- Corrected serum calcium ≤ 10.2 mg/dL

- Willing to attend all scheduled study visits, complete all study questionnaires, and
allow biological specimen collection, including a bronchoscopy

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception during and for at least 1 month
after completion of study therapy

- No life-threatening medical conditions that would preclude bronchoscopy, including
but not limited to, any of the following:

- Acute cardiac failure

- Uncontrolled hypertension

- Uncontrolled diabetes mellitus

- Unstable coronary artery disease

- No severe metabolic disorders that would preclude calcitriol administration

- No history of any other malignancy within 3 years except for nonmelanoma skin cancer
or cervical carcinoma in situ

- No history or evidence of kidney stones

- No patients who are susceptible to calcium-related dysrhythmias

- No known hypersensitivity to calcitriol

- No known allergies to tree nuts (i.e., almonds)

PRIOR CONCURRENT THERAPY:

- At least 2 months since prior and no concurrent calcium supplements

- Concurrent multivitamin supplement allowed provided the amount of vitamin D in the
supplement is not in excess of the recommended daily dose

- No concurrent thiazides, phenobarbital, or digitalis

- No concurrent digoxin

- No concurrent bile acid binding drugs (i.e., cholestyramine, colestipol)

- No concurrent danazol or aluminum-based antacids

- No concurrent ketoconazole or other azole antifungals