Preoperative Computed Tomography Features as Predictors of Malignancy and Survival in Canine Adrenal Tumours

As computed tomography (CT) becomes more commonly used in clinical practice for staging and surgical planning of dogs with adrenal tumours, there remain few reports on CT characteristics of malignant adrenal tumours and none that correlate imaging findings with survival. This retrospective study attempts to evaluate preoperative CT characteristics that are associated with malignancy and those that may be associated with shorter survival in dogs with surgically addressed adrenal tumours. CT scans performed at a single tertiary care facility were examined by a single blinded radiologist, and the findings were correlated with histopathology results as well as short- and long-term survival. A total of 226 adrenal tumours were assessed from 201 individual patients. The overall median survival time for adrenal tumours was 671 days. Dogs undergoing unilateral versus bilateral adrenalectomies had longer survival, with a median survival time of 697 versus 623 days (p = 0.02). Consensus histopathologic diagnosis as malignant versus benign was not associated with a significantly shorter survival time, 952 versus 1514 days, p = 0.04, q = 0.25. No CT features were associated with shortened long-term survival times on multivariate analysis. Excluding deaths within 24 h of surgery, splenectomy was predictive for hazard of death and was retained on multivariate analysis p = 0.03, HR = 2.33. Age (p = 0.0001, HR = 1.23) and concurrent ureteronephrectomy at the time of adrenalectomy (p = 0.042, HR = 2.45) were shown to affect long-term survival and were retained on multivariate analysis. This information may be useful when prognosticating outcomes for pet owners presenting for surgery.