Magnetic resonance imaging of the bone marrow (MRBM) as an outcome measure for patients with metastatic prostate cancer

Abstract

14521 Background: Previously we have shown that the distribution of osseous metastases in prostate cancer (PC) matched the distribution of the normal adult marrow. Over 90% of advanced PC patients have disease in bone. Imaging the marrow has the potential to allow detection of metastases before osseous response has occurred and provides a three dimensional volumetric measure that can be quantified and monitored serially for changes over time. We are examining the use of MRBM as an indicator of treatment effect in patients with metastatic PC. Methods: Patients with PC and 2 or more MRBM surveys were identified and extracted from a database of all patients at MSK who have had radiologic studies. Cases were further identified on the basis of having metastatic disease, followup MRBM within 4–7 months, concurrent PSA and bone scans. MRI reports were stratified as either “progression” or “stable/improved” assuming a clinician would change therapy if progression was documented. PSA was similarly recorded, using a definition of ≥ 25% increase from baseline to indicate progression. Bone scans were stratified on the basis of new lesions verses no new lesions. Results: Twenty-five patients were eligible for review with a median baseline PSA of 7.34 ng/ml (0.05–473 ng/ml). Average percent change of PSA at followup was 651% (0–11033%). Treatment included: hormones (11), chemotherapy (5), calcitriol (4) and observation (5). The change in MRBM was concordant in 73% of patients with progression by PSA. These results are demonstrated below in the Table. Conclusions: MRBM is a novel means to assess metastatic disease to bone. This preliminary analysis suggests that MRBM can be early indicator of treatment failure. We plan to explore it prospectively as an outcome measure for PC using a lesional analysis. Grant Support: PEPSICO, PCF, NCI 102544, CA102544 and 5T32CA09207. [Table: see text] [Table: see text]