gms | German Medical Science

Objective: Cement augmentation via percutaneous vertebroplasty (VP) or kyphoplasty (KP) for treatment of spinal metastasis is a well-established treatment option. However, leakage of the liquid cement out of the vertebral body into the surrounding vessels with subsequent embolization is a well-known risk of pressure directed injection. We assessed whether elevated intrametastatic pressure during cement augmentation results in an increased dissemination of tumor cells into the vascular circulation. Since circulating tumor cells (CTCs) may have a prognostic value, we further assessed their viability, marker expression (cytokeratin K and HER2) and perioperative frequency.

Method: In this single-center, prospective study, peripheral blood samples for CTC analyses were obtained from 19 patients with metastatic involvement of the spinal column on three time points: preoperatively, 20 min post cement augmentation and four days postoperatively. CTC detection was performed using CellSearch™; an FDA approved automated immunomagnetic CTC detection system.

Results: Up to now, 19 patients were included (6 male and 13 female, mean age 61.1 years, range 45 - 76 years). Histopathological findings of the primary tumors showed lung- (n = 3, 15.8%), colorectal (1), renal- (1), hepatocellular- (1), prostate- (1), esophageal-carcinoma (1) and breast cancer in 11 patients (57,9%). Cement augmentation was performed in vertebral bodies of the thoracic (n = 12) or lumbar (n = 11) spine. In 7 patients multiple levels were augmented. EpCAM+ CTCs were detected preoperatively in 17 patients (mean: 26.8 CTCs/7.5ml blood, SD 47.7). 20 min post-surgery a significant increase of CTC was detected (mean: 64.7 CTCs, SD: 55.9, p = 0.041) and on day four the mean CTC counts returned to the preoperative level (mean: 20.4, SD: 24.4, p = 0.005).

Conclusions: This is the first study to report that peripheral CTC are temporarily significantly increased due to the vertebral augmentation procedure. Whether CTC dissemination leads to new metastatic seeding or affects the prognosis will be assessed in future studies. But taken together, our findings provide a rationale for the development of new strategies to reduce the increased dissemination of CTC associated with vertebroplasty.