The stability of osseous metastases of the spine in lung cancer - a retrospective analysis of 338 cases

Background: The objective of this retrospective analysis is to systematically assess osseous lesions on the basis of a validated scoring system in terms of stability and fractures prior to and following radiotherapy in 338 lung cancer patients with bone metastases in the vertebral column. Methods: The stability of 338 patients with 981 osteolytic metastases in the thoracic and lumbar spine was evaluated retrospectively on the basis of the Taneichi-Score between January 2000 and January 2012. Results: 64% (215 patients) were classified stable prior to radiotherapy. Of the stable osseous metastases, none were rated unstable in the further course (p < 0.001, McNemar test). Of the 123 patients in whom the metastases were classified unstable prior to radiotherapy, 21 patients (17%) were classified stable after three months, and 30 patients (24%) stable after six months. A pathological fracture was diagnosed in 62 patients (18%) prior to radiotherapy. Regarding cases of osteolytic metastases of the vertebral bodies in which no fractures could be detected prior to the start of therapy, fractures occurred in 2% of all patients (n = 7) within six months following radiotherapy. Conclusions: Our analysis demonstrated that pathological fractures following radiotherapy occur in the very minority of vertebral lesions for patients with a favorable outcome. The use of a systematic radiological scoring system to classify osteolytic metastases of the vertebral column has shown to be feasible in daily routine. Prospective clinical trials are warranted in order to analyse, to what extent patients with osseous metastases can be mobilized by physiotherapy for strengthening the paravertebral muscles before radiotherapy effects can be measured by means of radiological recalcification.