Newly Diagnosed Brain Tumours: When Is a Staging CT Required?

Abstract

AIMS Newly diagnosed brain lesions (NBL) on imaging can be either primary or secondary in nature. Of these, only secondary brain lesions routinely require a staging CT chest, abdomen, and pelvis (CTCAP). But owing to lack of clear guidelines, all NBLs usually receive a staging investigation. This leads to over investigation of primary brain tumors. We sought to identify predictors of secondary brain lesions using CT head alone to guide the selection of patients for a CTCAP. METHOD Patients with NBLs referred to a tertiary Neurosurgical centre were reviewed. For protocol creation, data was collected from patients referred between July to December 2020, potential predictor variables were identified. Potential candidate protocols identified were assessed in a protocol-testing stage using data from a different set of patients. Sensitivity, specificity, and area under the curve (AUC) values were computed for each protocol. RESULTS The protocol-creation stage included 222 patients. Multivariate logistic regression analysis identified candidate protocols. This identified the most sensitive predictors of metastatic disease as : a previous history of cancer, multiple lesions, lesion size <4cm, and infratentorial location. A final protocol identified was found to have a sensitivity of 99.1% (AUC 0.704). CONCLUSION The use of the above protocol derived from this study would reduce unnecessary CTCAPs by 37.5-40% overall. Patients who do not fulfil at least one of the above said criteria on the first assessment should not have a CTCAP initially. This protocol reduces the financial and time costs from unnecessary CTCAPs as well as reduces patient exposure to radiation and contrast.