A Multicenter, Retrospective Analysis of Long-Term Survival in 255 Dogs With Pheochromocytoma Treated With...

The survival of dogs with pheochromocytoma (PCC) treated with adrenoreceptor antagonists has not been described or compared to surgically managed cases.

The objective of this study is to evaluate the survival of medically and surgically managed dogs with PCC and investigate factors associated with survival.

Two hundred fifty-five dogs with PCC, treated with alpha-adrenoreceptor antagonists (AA) without adrenalectomy (Group 1, n = 75), adrenalectomy +/- AA (Group 2, n = 128), or neither treatment (Group 3, n = 52).

Retrospective, multicenter review of medical records. Median overall survival time (OST) for Groups 1 and 2 combined was calculated using Kaplan-Meier estimates, and then compared between Group 1 and Group 2 using Log-Rank testing. Cox proportional hazard analysis identified factors associated with survival in Groups 1 and 2 individually and combined.

Median OST for all cases was 854 (95% CI: 572-1136) days. Median OST was lower in Group 1 (247 days, 95% CI: 76-418 days) than in Group 2 (927 days, 95% CI: 587-1267 days; p < 0.001). In Group 2, 88/92 dogs (97.8%) that received presurgical AA treatment survived to discharge compared to 23/27 (85.2%) that did not receive AA pretreatment (p = 0.03). Lack of clinical signs at presentation was associated with increased survival in both groups combined (HR 0.5; 95% CI 0.3-0.9; p = 0.02) and in Group 2 alone (HR 0.3; 95% CI 0.1-0.7; p = 0.01).

Dogs with PCC treated with adrenalectomy have longer survival compared to those managed with AA without adrenalectomy.