No association between excessive wound complications and preoperative high-dose, hypofractionated, image-guided radiation therapy for spine metastasis

Abstract

Object Radiation therapy is known to impair wound healing. Higher dose per fraction is believed to increase this risk. This study sought to quantify rates of wound complication in patients receiving preoperative conventionally fractionated radiotherapy (XRT) or high-dose hypofractionated image-guided radiation therapy (IGRT) for spinal metastasis, and to identify predictors of wound complication. Methods The records of 165 consecutive patients who underwent spine surgery for metastasis at Memorial Sloan–Kettering Cancer Center between 1999 and 2010, with a history of prior radiation therapy, were reviewed. Patients with primary spine tumors, 2 courses of prior radiation therapy to the surgical site, total dose < 9 Gy, or radiation therapy adjacent to or partially overlapping the surgical site, were excluded. One hundred thirty patients received XRT (≤ 3 Gy/fraction) and 35 received IGRT (> 3 Gy/fraction). The total dose prescribed to the 100% isodose line to treat the planning target volume was 18–30 Gy in 1–5 fractions. Clinical factors evaluated included age, Karnofsky Performance Scale score, body mass index, presence of diabetes, smoking, ambulatory status, prior surgery at same spinal site, preoperative laboratory results (hemoglobin, lymphocyte count, and albumin), perioperative chemotherapy or steroids, estimated blood loss, extent of stabilization hardware, time between radiation therapy and surgery, number of vertebral bodies irradiated, total radiation dose, and dose per fraction of radiation therapy. Wound complication was defined as poor healing, dehiscence, or infection. Potential predictors of wound complication were assessed by univariate analyses using competing-risk methods to adjust for risk of death. Results For XRT patients, median dose was 30 Gy (range 11.5–70 Gy) with 72% of them receiving 3 Gy × 10 fractions. For IGRT patients, 66% received 18–24 Gy × 1 fraction and 23% received 6 Gy × 5 fractions. Groups differed only by the mean number of vertebral bodies treated (4.6 XRT and 1.8 IGRT, p < 0.0001). Wound complications occurred at a median of 0.95 months (range 0.4–3.9 months). A total of 22 wound events occurred in the XRT group and 2 in the IGRT group. The 6-month cumulative incidence of wound complications for XRT was 17% and for IGRT was 6%. There was no significant difference in wound complications between groups (IGRT vs XRT: hazard ratio 0.31, 95% CI 0.08–1.3; p = 0.11). Higher dose per fraction appeared to be associated with a lower risk of wound complication (hazard ratio 0.27, 95% CI 0.06–1.15; p = 0.08), which trended toward significance. Univariate analyses did not reveal any significant predictors of wound complications. Conclusions Patients who underwent XRT or IGRT did not have significantly different rates of postoperative wound complications. This finding may be explained by the treatment of fewer vertebral bodies in IGRT patients, or by the low overall number of total events. With a wound complication rate of 6%, preoperative IGRT, a highly conformal treatment, resulted in a very low rate of surgical wound complication.

Short-segment percutaneous pedicle screw fixation with cement augmentation for tumor-induced spinal instability

“…Of note, in this series, most patients underwent radiation therapy within 4 weeks of surgery. Preoperative or postoperative radiation within this window is generally considered to increase the risk of wound dehiscence and infection [44]. In general, at least 3 weeks are therefore required after open surgery before starting cEBRT to the area.…”

Costs and readmission rates for the resection of primary and metastatic spinal tumors: a comparative analysis of 181 patients

“…Over the past several years, there has been a transition to the use of stereotactic radiosurgery via high-dose, hypofractionated, image-guided radiation therapy, rather than conventional fractional radiotherapy. 20 A recent published study by Harel et al concluded that modern-day adjuvant stereotactic radiosurgery (single fraction) to the spine following surgery for metastasis allows high local control rates, but at the same time delivers less radiation to the wound. 18 Additional contemporary studies are needed to further evaluate this topic.…”

Hybrid surgery–radiosurgery therapy for metastatic epidural spinal cord compression: A prospective evaluation using patient-reported outcomes

“…Durable tumor control has been shown with this therapy 7 along with low risk of complications such as hardware failure and wound infections. 20,21 The NOMS framework, 22 which consists of neurologic, oncologic, mechanical stability and systemic considerations, provides evidence-based guidance for treatment decisions in patients with spinal metastases. Patients with high-grade MESCC 23 and radioresistant tumors (ie, tumors that are known to be resistant to conventional external beam radiotherapy) require separation of the tumor from the thecal sac, in order to allow adequate SRS dosing to include the entire volume, including the epidural margin, while conforming to safety constraints to the spinal cord.…”