RATIONALE: Diagnostic procedures, such as radionuclide imaging using calcium-41 (41Ca) chloride aqueous solution, may help predict progressive disease in patients with prostate cancer and bone metastasis.

PURPOSE: This clinical trial is studying how well calcium-41 (41Ca) chloride aqueous solution works in diagnosing patients with prostate cancer and bone metastasis.

OBJECTIVES:

Primary

• To measure the pharmacokinetics of a single oral dose of calcium-41 (41Ca) chloride aqueous solution (^41Ca) over 18 months in patients with hormone-refractory prostate cancer and bone metastasis.
• To correlate the ^41Ca-tracer kinetics with time to disease progression, skeletal-related events, and death.

Secondary

• To correlate modulations in baseline urinary ^41Ca clearance with changes in clinically relevant disease parameters, including isotope bone scan data and PSA.
• To combine bone turnover assessments with ^41Ca and collagen/bone cell biomarkers with clinical imaging techniques, especially isotope bone scans, to provide improved stratification of disease stage.

OUTLINE: Patients receive oral calcium-41 (41Ca) chloride aqueous solution (^41Ca) on day 1. Some patients also receive oral calcium-46 (46Ca) chloride aqueous solution (^46Ca).

Urine and blood specimens are collected periodically for 18 months. Blood samples are assayed for bone collagen residues, bone alkaline phosphatase, and PSA. Urine specimens are assessed for ^41Ca/Ca. Isotope bone scintigraphy is use to measure radioactivity.

After completion of study treatment, patients are followed up periodically for 3 years.

Eligibility Criteria

• Histologically or cytologically confirmed prostate cancer with a Gleason score available or interpretable
• Prostate cancer deemed to be hormone refractory or androgen independent within the past 12 months
• Evidence of bony metastasis
• Either be receiving bisphosphonate therapy or have received a bisphosphonate within the last 18 months. Participants who are on not on bisphosphonate therapy nor have received it within the last 18 months should currently be on Denosumab therapy. All other anti-cancer therapies are allowed.
• Age >18 years
• ECOG performance status 0-2 (Karnofsky >50%).
• Life expectancy of 6 months or greater.
• Investigators are encouraged to follow good medical practice to assure that all participants have adequate hematologic, hepatic, and renal function.
• Recent or planned isotope bone scan, within 12 months prior to enrollment.
• Ability to understand and the willingness to sign a written informed consent document.

Exclusion Criteria

• Participants will be excluded who have experienced a severe skeletal related event (SRE)within the past 3 months. For this study, an SRE consists of any of the following: palliative radiotherapy to bone, pathologic fractures, spinal cord compression, hypercalcemia of malignancy, and surgery to bone to treat or prevent a fracture.
• Uncontrolled intercurrent illness including, but not limited to ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, interstitial lung disease, chronic kidney disease, hyperthyroidism, or psychiatric illness/social situations that would limit compliance with study requirements.
• Corrected serum calcium <8.0 mg/dL (2.0 mmol/L) or ≥12.0 mg/dL (3.0 mmol/L)

Not required

Patients were followed by good clinical practice guidelines, but toxicities were not recorded for data collection purposes.

This trial was IRB closed after accruing only 13 patients of a potential 30 due to contract period expiring. This termination prior to accrual goal achievement led to small numbers of subjects analyzed with no statistical analysis done.