Efficacy of Transsphenoidal Hypophysectomy in Treatment of Dogs with Pituitary-Dependent Hyperadrenocorticism

Abstract

The long-term survival, disease-free fractions, and the complications of hypophysectomy in 150 dogs with pituitary-dependent hyperadrenocorticism (PDH) were examined in a prospective study. Long-term survival and disease-free fractions in relation to pituitary size were analyzed by the Kaplan-Meijer estimate procedure. The 1-, 2-, 3-, and 4-year estimated survival rates were 84% (95% confidence interval [CI], 76-89%), 76% (67-83%), 72% (62-79%), and 68% (55-77%), respectively. Treatment failures included procedure-related mortalities (12 dogs) and incomplete hypophysectomies (9 dogs). The 1-, 2-, 3-, and 4-year estimated relapse-free fractions were 88% (CI: 80-93%), 75% (64-83%), 66% (54-76%), and 58% (45-70%), respectively. Postoperative reduction of tear production (58 eyes in 47 dogs) was often reversible but remained low until death in 11 eyes of 10 dogs. Central diabetes insipidus (CDI) occurred more frequently (62%) in dogs with enlarged pituitaries than in dogs with nonenlarged pituitaries (44%). Survival and disease-free fractions after hypophysectomy were markedly higher in dogs with nonenlarged pituitaries than in dogs with enlarged pituitaries. Transsphenoidal hypophysectomy is an effective treatment for PDH in dogs. The survival and disease-free fractions after hypophysectomy decrease and the incidence of CDI increases with increasing pituitary size. Therefore, early diagnosis of PDH is important and transsphenoidal hypophysectomy is expected to have the best outcome when used as primary treatment for dogs with nonenlarged or moderately enlarged pituitaries.

Survival, Neurologic Response, and Prognostic Factors in Dogs with Pituitary Masses Treated with Radiation Therapy and Untreated Dogs

“…13 Radiation therapy (RT), surgery, or a combination of both are the treatments of choice for most intracranial masses. [14][15][16][17] RT is the most commonly employed treatment for pituitary tumors in dogs. 14,17,18,19 Most studies evaluating RT demonstrated the potential for decreasing tumor size and prolonging survival.…”

“…[14][15][16][17] RT is the most commonly employed treatment for pituitary tumors in dogs. 14,17,18,19 Most studies evaluating RT demonstrated the potential for decreasing tumor size and prolonging survival. Treatment protocols with a large dose per fraction, however, were associated with brain toxicity, including formation of second tumors and necrosis.…”

Efficacy of Transsphenoidal Surgery on Endocrinological Status and Serum Chemistry Parameters in Dogs with Cushing's Disease

“…In the previous reports, remission and recurrence were defined by the urine cortisol-to-creatinine ratio (UCCR) in duplicate at 24 hr after glucocorticoid medication and resolution/return of clinical signs of hypercortisolism [23,24]. This is the most commonly used method in humans to define remission or recurrence.…”

“…There are many reports of postoperative results with regard to long-term survival and the recurrence fraction in humans [6]. However, in canine Cushing's disease, only two reports, by the same group of researchers, describe postoperative results with regard to long-term survival and the recurrence fraction in significant numbers of Cushing's disease dogs [23,24]. In the present study, the dogs that died of unrelated causes or that were still alive at the time of follow-up were counted as censored cases.…”

“…Moreover, follow-up investigations of canine Cushing's disease treated by TSS have shown effective outcomes [23,24]. A few reports have demonstrated long-term survival, diseasefree fractions, complications of TSS and the effects of longterm alternations in endocrinological status in canine Cushing's disease [23,24].…”