Prognostic factors for outcome after transsphenoidal hypophysectomy in dogs with pituitary-dependent hyperadrenocorticism.
OBJECTIVE
The aim of this study was to determine prognostic factors for outcome after transsphenoidal hypophysectomy in dogs with pituitary-dependent hyperadrenocorticism (PDH).


METHODS
One veterinary neurosurgeon performed transsphenoidal hypophysectomies in 181 dogs with PDH over a 12-year period. Survival analysis was performed with the Kaplan-Meier method. Prognostic factors were analyzed with the univariate Cox proportional hazard analysis followed by stepwise multivariate analysis. The log-rank test was used to assess disease-free fractions in three groups categorized according to early postoperative urinary corticoid/creatinine (C/C) ratios.


RESULTS
Multivariate analysis revealed that old age, large pituitary size, and high preoperative concentrations of plasma adrenocorticotropic hormone were associated with an increased risk of PDH-related death. In addition, large pituitary size, thick sphenoid bone, high C/C ratio, and high concentration of plasma alpha-melanocyte-stimulating hormone (alpha-MSH) before surgery were associated with an increased risk of disease recurrence in the dogs that went into remission after hypophysectomy. Disease-free fractions were significantly higher in dogs with postoperative urinary C/C ratios in the lower normal range (< 5 x 10(-6)) than in dogs with postoperative C/C ratios in the upper normal range (5-10 x 10(-6)).


CONCLUSIONS
The results of this study indicate that pituitary size, sphenoid bone thickness, plasma alpha-MSH concentration, and preoperative level of urinary cortisol excretion are predictors of long-term remission after transsphenoidal hypophysectomy for PDH in dogs. Urinary C/C ratios measured 6 to 10 weeks after surgery can be used as a guide for predicting the risk of tumor recurrence.
Hanson
Jeanette M
JM
Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands. j.m.hanson@uu.nl
Teske
Erik
E
Voorhout
George
G
Galac
Sara
S
Kooistra
Hans S
HS
Meij
Björn P
BP
D000308:Adrenocortical Hyperfunction / Q000401:mortality / Q000601:surgery* / Q000662:veterinary*; D000818:Animals; D004283:Dog Diseases / Q000401:mortality / Q000601:surgery*; D004285:Dogs; D005260:Female; D007016:Hypophysectomy / Q000401:mortality / Q000662:veterinary*; D008297:Male; D018365:Neoplasm, Residual / Q000401:mortality; D047748:Pituitary ACTH Hypersecretion / Q000401:mortality / Q000601:surgery* / Q000662:veterinary*; D010902:Pituitary Gland / Q000601:surgery; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D012008:Recurrence; D012074:Remission Induction; D012307:Risk Factors; D013100:Sphenoid Bone / Q000601:surgery; D015996:Survival Rate