Role of postoperative radiation therapy after stabilization of fractures caused by metastatic disease.

PURPOSE: Although orthopedic stabilization is frequently performed for pathological fractures caused by metastatic disease, no data is available to support the value of postoperative radiation therapy (S+RT) in this setting. METHODS AND MATERIALS: We reviewed 64 orthopedic stabilization procedures in 60 consecutive patients with metastatic disease to previously unirradiated weight-bearing bones with pathological or impending pathological fracture (femur 91%). Thirty-five sites that received adjuvant S+RT were compared to 29 sites that were treated with surgery alone (SA). Many potential prognostic variables were evaluated. Endpoints were: functional status (FS) of the extremity (1 = normal pain free use; 2 = normal use with pain, 3 = significantly limited use; 4 = nonfunctional extremity), subsequent orthopedic procedures to the same site, and survival following surgery.
RESULTS: At the univariate level, S+RT (p = 0.02) and prefracture FS (p = 0.04) were the only significant predictors of patients achieving an FS of 1 or 2 after surgery. On multivariate analysis, only postoperative RT was significantly (p = 0.02) associated with attaining FS of 1 or 2 after surgery. The predicted probability of achieving FS 1 or 2 at any time was 53% for S+RT vs. 11.5% or SA (multiple logistic regression, p < 0.01). Evaluation of FS following surgery revealed that S+RT group had significantly better function in the 1-3, 3-6, and 6-12 month postoperative periods (chi-square, p < 0.04 for each time period). Second orthopedic procedures to the same site were more common in the SA group than the S+RT group (log rank, p = 0.03). Actuarial median survival of S group was 3.3 months compared with 12.4 months for the S+RT group (log rank, p = 0.02), confirming the beneficial association with survival shown by the multivariate Cox regression analysis (p = 0.025).
CONCLUSION: Although this retrospective study is subject to possible biases, several analyses adjusting for numerous prognostic factors uniformly indicate S+RT is the most important factor in patients achieving and maintaining normal functional status (+/- pain). Further, the S+RT group was associated with fewer orthopedic procedures as well as an improved overall survival. The improved survival may be due to (a) more favorable patients being referred for RT (possible section bias), or (b) improved functional status in the S+RT group. This study quantitatively supports the benefit of postoperative RT in this setting.