Long‐Term Survival of Dogs with Adrenal‐Dependent Hyperadrenocorticism: A Comparison between Mitotane and Twice Daily Trilostane Treatment

Abstract

BackgroundTreatment of adrenal‐dependent hyperadrenocorticism (ADH) involves either surgical resection of the adrenal tumor or medical therapy. For many years, mitotane has been considered the medical treatment of choice for dogs with ADH.ObjectivesThe aim of this study was to determine survival and prognostic factors for dogs with ADH treated with mitotane and trilostane.AnimalsTwenty‐six dogs with ADH were included in the study.MethodsFourteen dogs were treated with mitotane and 12 dogs were treated with trilostane. Medical records were reviewed. Epidemiologic factors, signalment, clinicopathologic abnormalities, endocrine test results, and treatment protocols were evaluated to identify potential predictive factors of overall survival time.ResultsSurvival times of dogs treated with mitotane (median, 15.6 months) or trilostane (median, 14.0 months) were not significantly different. Using univariate analysis, age and postadrenocorticotropic hormone cortisol concentrations were inversely correlated with survival time. The multivariate model also identified weakness at presentation as a negative prognostic indicator.Conclusion and Clinical ImportanceThe type of medical treatment (mitotane versus trilostane) does not influence survival time in dogs with ADH; therefore, trilostane, a drug with less frequent and milder adverse effects, might be used as the primary medical treatment when adrenalectomy cannot be performed.

Volumetric‐modulated arc stereotactic radiotherapy for canine adrenocortical tumours with vascular invasion

“…In a recently published paper including 20 canine NSATs, the tumour size and amount of growth at follow‐up exams were identified as negative predictive factors (Arenas et al . ). In the same retrospective study, the authors stated that a tumour size of 20 mm is the optimal cut‐off point for adrenalectomy (Arenas et al .…”

“…In the same retrospective study, the authors stated that a tumour size of 20 mm is the optimal cut‐off point for adrenalectomy (Arenas et al . ). Other dimensional criteria in veterinary medicine can be represented by the reported differences between carcinomas and adenomas (Capen ).…”

“…The resulting median overall survival of 1030 days, corresponding to 33·8 months, is particularly encouraging in comparison with the median survival of 17·8 months reported by Arenas et al . () regarding 20 dogs with NCSATs‐treated without adrenalectomy. Moreover, considering the recent and extensive report on 52 dogs undergone adrenalectomy (Massari et al .…”

Treatment of canine and feline hyperadrenocorticism: trilostane and the alternatives

“…Older age and heavier weight are negative prognostic factors reported in several studies; higher one hour post-ACTH serum cortisol, weakness at presentation, hyperphosphataemia and severity of clinical signs have also been reported as negative prognostic indicators (Kintzer and Peterson, 1991;Barker et al, 2005;Clemente et al, 2007;Arenas et al, 2014;Fracassi et al, 2014). There are a small number of studies reporting use of alternative drugs to manage HAC.…”

“…Twicedaily trilostane appeared to have a more favourable outcome for the treatment of PDH compared to a mitotane adrenolytic protocol, having median survival times of 900 days and 720 days, respectively (Clemente et al, 2007). Both trilostane and mitotane have been used to treat AT and no study to date has reported significantly different survival times for either drug (Helm et al, 2011;Arenas et al, 2014).…”