Questionable indication for postoperative radiotherapy after surgery for metastases of the major long bones: A single-centre cohort study of 552 fractures/526 patients

• Postoperative radiotherapy was not associated to lower tumor-related implant failure after surgery for metastasis in major long bones. • Postoperative radiotherapy was associated with increased revision risk in patients treated with prostheses. • Findings question routine use of radiotherapy after surgery of the major long bones and suggest it should be used only in selected cases. The use of postoperative radiotherapy (PORT) as an adjunct to orthopaedic surgery of the long bones is widely recommended. Evidence of the benefits is however sparse. The primary research question of this study was whether PORT reduces the incidence of local failure after orthopaedic surgery for metastatic disease of the long bones. A prospectively collected database was retrospectively reviewed. A total of 552 fractures/526 patients were included. Primary endpoint was secondary surgery due to implant failure due to local tumour progression. The main analysis used a competing risk model with death as a competing event. PORT was administered in 197 cases, the median initiation time was 42 days and the most common schedule was 4 Gy × 5. 33 cases (6%) required revision attributed to tumour related implant failure. The cumulative incidence of failure was higher in the PORT group (p = 0.038). When dividing cases into subgroups depending on surgical method PORT had no effect in the osteosynthesis group and was significantly associated with a worse outcome in the prosthesis group. PORT dose and timing were not associated with failure rates. In this cohort, PORT was associated with a significantly increased risk of tumour related failure in patients treated with a prosthesis. There was no significant effect in the osteosynthesis subgroup. Our results indicate that there is no clear evidence for the universal use of PORT.