Patterns of care and survival outcomes of palliative radiation for prostate cancer with bone metastases: comparison of ≤5 fractions to ≥10 fractions

David Schreiber, Joseph Safdieh, Daniel J. Becker, David Schwartz


Background: To review the palliative radiation fractionation regimens, trends and survival of men within the National Cancer Database (NCDB) diagnosed with prostate cancer and bony metastases.
Methods: A total of 3,871 patients from the NCDB were included in the analysis (patients treated from 2004–2012). The following fractionation regimens were analyzed [8 Gy × 1, 4 Gy × 5 (short course radiation therapy)], were compared to 3 Gy × 10, 2.50 Gy × 14–15 and 2 Gy × 20–30 (long course radiation ntherapy). Descriptive statistics, multivariable logistic regression and multivariable cox regression analysis were utilized to assess the data.
Results: Longer fractionation schemes were used for 91.7% of patients. Treatment at an academic center (OR, 2.93), increasing distance from treatment center (OR, 1.48–1.59), treatment to the ribs (OR, 2.47), and year of diagnosis 2009 or later (OR, 2.31–3.26) were associated with an increased likelihood of receiving short course radiation, while treatment to the spine (OR, 0.34) was associated with a decreased likelihood of short course radiation. On multivariable analysis, longer course of radiation was associated with increased overall survival (HR =0.66; 95% CI: 0.56–0.78, P<0.001.). However, on landmark analysis this difference disappeared once limiting the survival analysis to men who survived ≥18 months [HR =0.83; 95% CI: 0.62–1.11, P=0.21].
Conclusions: Fractionation schemes of ≥10 treatments remain the dominant palliative course of radiation therapy offered for metastatic prostate cancer. However, utilization of ≤5 fractions is slowly increasing, particularly at academic centers.