65. Contributing risk factors in patients receiving chemotherapy or immunotherapy undergoing surgical stabilization for spinal metastatic disease

Abstract

<h3>BACKGROUND CONTEXT</h3> Advancements in novel, more efficacious, oncological chemo- and immunotherapies in the last decade have led to significantly prolonged survival rates in cancer patients. The vertebral column is the most common site of bony metastasis, consequently, the incidence of metastatic spine disease has increased. Much work has been done assessing postoperative complications in spine surgery secondary to radiotherapy; however, little is known on the contributing risk factors to postoperative spine complications secondary to immunotherapy. <h3>PURPOSE</h3> The purpose of this study was to assess independent risk factors for postoperative complications after surgical stabilization of spinal metastases in patients receiving either chemotherapy or immunotherapy. <h3>STUDY DESIGN/SETTING</h3> Retrospective analysis. <h3>PATIENT SAMPLE</h3> Fifty-seven patients. <h3>OUTCOME MEASURES</h3> Demographic information, tumor charecteristics and operative paramters were reviewed from the electrical medical records. Postoperative complications were assessed until 30 days after surgery. <h3>METHODS</h3> Our institution's TriNetX database was reviewed from September 2011 to September 2020. ICD-10 codes were employed to identify all patients with Stage IV metastatic disease to the vertebral column. CPT codes were utilized to capture patients in this cohort who received either chemotherapy or immunotherapy subsequently followed by surgical treatment. Patients were excluded from the study if they were younger than 18 years or received radiation therapy to the spine. Categorical outcomes were compared between patients receiving chemotherapy vs immunotherapy via Fisher's exact test analysis. Identification of risk factors for 30-day complications was achieved using a fitted model with binary logistic regression. Threshold for significance was established at p < 0.05. <h3>RESULTS</h3> Overall average age was 64.98+/-13.19 years. Average age for the chemotherapy group and the immunotherapy group was 66.64+/-12.88 and 62.52+/-13.5 (p=0.307) respectively. Among the chemotherapy group, 21 had smoked tobacco regularly, while 12 smoked regularly in the immunotherapy group (0.472). CCI (1.62+/-0.95 vs. 8.39+/-1.67, p=0.473) and ECOG (9.12+/-1.95 vs 1.7+/-1.08, p=0.604) were comparable between the two groups. Breast (9), lung (7), prostate (7) cancers were more commonly treated with chemotherapy, while immunotherapy was more commonly used to treat melanoma (10) and lung (8) cancers (p < 0.001). There was no significant difference across the groups with regards to complications. Multivariate analysis showed that smoking is an independent predictive factor for postoperative complications. <h3>CONCLUSIONS</h3> Surgical intervention, as an adjunct to immunotherapy and chemotherapy, is beneficial for sustained improvement in pain, neurologic and functional outcomes. We demonstrated, through our institution retrospective patient series, any evidence of tobacco use is a significant risk factor which may contribute to postoperative surgical complications. To our knowledge, this is the first study of its kind which assesses risk factors potentially associated with immunotherapy. Although our analysis is limited by a relatively low-powered study, future studies reviewing a larger patient cohort are needed to better conclude on possible associations between the use of immunotherapy and spine surgical stabilization in metastatic spine disease. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.