You are here
Prognostic value of metastasis pattern for morbidity in prostate cancer measured by quantitative bone scintigraphy.
Background: Quantification of bone metastases in the skeleton expressed as Bone Scan Index (BSI) and location of these are prognostic factors for mortality and morbidity in prostate cancer (PC). The purpose of this study was to identify prognostic factors for morbidity in PC based on location and extent of metastases derived from quantified bone scintigraphies (BS). Methods: Data from 107 consecutive patients with noncurable hormone-naive PC with available pretreatment 99mTc-MBP BS from the period 2003-2007 were retrospectively analyzed. BSI and location of metastases were measured from the BS using Exini Bone 1.0 (Exini AB, Sweden). Observed BSI for 8 regions was compared to the expected BSI calculated from the red bone marrow distribution. A logistic regression model for having skeletal events (SE), defined as external beam radiation for bone pain, spinal cord compression or pathological fracture at any location in the skeleton based on pre-treatment BSI, metastases distribution and PSA, was made. Results: The average BSI for the 72 patients with metastases at diagnosis was 1.063. Metastatic distribution expressed as the average BSI in these patients for each region was compared to the expected BSI of the same regions (Table). Patients with metastases to the skull had increased risk of SEs with OR: 4.2 (95% CL: 1.1-16.4, p<0.036) compared to the baseline patient with no metastases. No other regions, nor total BSI or PSA reached significance. Conclusions: PC does not metastasize randomly to the skeleton but clusters in the regions closest to the primary tumor. Patients with skull metastases have a higher risk of SEs throughout the skeleton. Very few SEs actually occurred in the skull region but skull metastases may indicate an atypical pattern of dissemination with a more aggressive phenotype of PC with more SEs.
|* Different from corresponding average BSI, same region, p<0.05 t-test.|