Resistance training concomitant to radiotherapy of spinal bone metastases – survival and prognostic factors of a randomized trial
PURPOSE
To compare the effects of resistance training versus passive physical therapy on bone survival in the metastatic bone during radiation therapy (RT) as combined treatment in patients with spinal bone metastases. Secondly, to evaluate overall survival and progression-free-survival (PFS) as well as to quantify prognostic factors of bone survival after combined treatment.


METHODS
In this randomized trial 60 patients were allocated from September 2011 until March 2013 into one of the two groups: resistance training (group A) or passive physical therapy (group B) with thirty patients in each group during RT. We estimated patient survival using Kaplan-Meier survival method. The Wald-test was used to evaluate the prognostic importance of pathological fracture, primary site, Karnofsky performance status, localization of metastases, number of metastases, and cerebral metastases.


RESULTS
Median follow-up was 10 months (range 2-35). Bone survival showed no significant difference between groups (p = .303). Additionally no difference between groups could be detected in overall survival (p = .688) and PFS (p = .295). Local bone progression was detected in 16.7 % in group B, no irradiated bone in group A showed a local progression over the course (p = 0.019). In univariate analysis breast cancer, prostate cancer, and the presence of cerebral metastases had a significant impact on bone survival in group B, while no impact could be demonstrated in group A.


CONCLUSIONS
In this group of patients with spinal bone metastases we were able to show that guided resistance training of the paravertebral muscles had no essential impact on survival concomitant to RT. Importantly, no local bone progression in group A was detected, nevertheless no prognostic factor for combined treatment could be evaluated.


TRIAL REGISTRATION
Clinical trial identifier NCT 01409720 . Registered 8 February 2011.