Introduction: Solitary brain tumors can propose a diagnostic dilemma due to the difficulty of differentiating between primary brain tumor and metastatic disease. Similar radiologic appearance on routine magnetic resonance imaging (MRI) necessitates the need of additional noninvasive methods of differentiation. The aim of this study is to determine the clinical utility of pre-operative Computed Tomography of the Chest/Abdomen/Pelvis (CT CAP) in detecting metastatic disease in patients with solitary brain tumors.
Methods: Our prospectively-maintained surgical database was reviewed for all patients undergoing craniotomy for a new diagnosis of brain tumor from 2011-2016. Patients were excluded if they had multiple brain tumors, underwent prior craniotomy for tumor, or if they harbored a history of cancer. 143 patients met inclusion criteria including a pre-operative CT CAP and a pathological diagnosis from resection or biopsy. All patients underwent pre-operative CT CAP as part of their work-up to evaluate for metastatic disease.
Results: Pre-operative CT CAP has a sensitivity of 0.90 and specificity of 0.94 for the detection of metastases. Malignancy discovered on pre-operative CT CAP can predict brain pathology with a positive predictive value of 0.88 and a negative predictive value of 0.95.
Conclusions: Pre-operative full body CT has clinical utility in aiding in the establishment of a differential diagnosis of primary brain tumor versus a solitary metastatic lesion. This non-invasive screening test has value when discussing with patients, pre-operatively, the benefits of craniotomy for biopsy or resection.
Patient Care: This study provides support for the clinical utility for whole-body CT screening in distinguishing between primary brain tumors and metastatic disease in patients with a solitary brain tumor of unknown histology. We have found this non-invasive screening test to be useful in discussing preoperatively the benefits of craniotomy for biopsy or resection versus biopsy of the primary malignancy site in the event of metastasis. Proper treatment of primary brain tumors and metastases can differ greatly based on pathologic findings, and the ability to make a prioritized differential diagnosis can alter oncologic treatment strategies.
Learning Objectives: 1) Describe the importance of using preoperative whole-body CT to characterize solitary brain lesions as either primary or metastatic
2) Discuss the clinical utility of CT CAP in differentiating primary versus metastatic brain lesions compared to other radiologic techniques
3) Identify an effective treatment based on preoperative CT CAP findings of primary versus metastatic disease