Outcome in dogs undergoing adrenalectomy for small adrenal gland tumours without vascular invasion

Risk factors influencing death prior to discharge in 302 dogs undergoing unilateral adrenalectomy for treatment of primary adrenal gland tumours

Adrenalectomies for canine adrenal tumours are associated with peri-operative morbidity and mortality. Objectives of this study included assessing the prognostic value of tumour- or surgery-related variables in predicting peri-operative mortality and overall survival in dogs undergoing adrenalectomies for primary adrenal tumours as well as pre-treatment with phenoxybenzamine on survival to discharge with pheochromocytomas specifically. A multi-institutional retrospective cohort study was performed across nine institutions. Electronic medical record searches identified 302 dogs which met the inclusion criteria. Data collected included dog-related, tumour-related, treatment-related, surgery-related, and outcome variables. Univariate and multivariable logistic regression and cox proportional hazards models were used to identify variables associated with death prior to discharge and tumour-related survival. Overall, 87% of dogs survived to discharge with a tumour-related survival time of 3.96 years. Post-operative complications were reported in 25%. Increased surgical time (p = 0.002) and pre-surgical medical treatment other than phenoxybenzamine (p = 0.024) were significantly associated with increased peri-operative mortality while ureteronephrectomy (p = 0.021), post-operative pancreatitis (p = 0.025), and post-operative aspiration pneumonia (p < 0.001) were significantly associated with decreased overall survival. Phenoxybenzamine pretreatment had no effect on peri-operative mortality. Thirty-seven of 45 (82%) dogs with pheochromocytomas not pretreated survived to discharge, and 50 of 59 (85%) dogs with pheochromocytomas pretreated with phenoxybenzamine survived to discharge (p = 0.730). This study provides information on risk factors for death prior to discharge and tumour-related survival that may help guide clinical management and owner expectations. In addition, the study findings challenge the previously reported benefit of phenoxybenzamine for pretreatment of dogs undergoing adrenalectomies for pheochromocytomas.

Laparoscopic vs. open adrenalectomy: perioperative data and survival analysis in 70 dogs with an adrenal tumor

Adrenalectomy is the treatment of choice in case of functional adrenal tumors and malignant adrenal incidentalomas. Laparoscopic adrenalectomy (LA) in dogs has gained popularity in recent years, however, clinical studies on large patient populations are scarce. This retrospective study describes perioperative and recurrence data, survival, and prognostic factors in 70 dogs that underwent LA or open adrenalectomy (OA) in our hospital between 2008 and 2022. Diagnosis was based on history, clinical signs, endocrine function tests and advanced diagnostic imaging. Laparoscopic adrenalectomy was performed in 42 dogs (n = 27 naturally occurring hypercortisolism, n = 4 pheochromocytoma, n = 1 pheochromocytoma with concurrent hypercortisolism, n = 10 incidentaloma) and OA in 28 dogs (n = 22 hypercortisolism, n = 3 pheochromocytoma, n = 3 incidentaloma). Bilateral adrenalectomy was performed in 8/70 dogs. Surgical duration of LA and OA did not differ significantly in unilateral and bilateral procedures (P = 0.108 and P = 0.101, respectively). Systemic hypertension occurred in 7/41 and 1/28 dogs during LA and OA, respectively (P = 0.130). Hypotension occurred in 2/41 and 4/28 dogs during LA and OA, respectively (P = 0.214). A total of 40/42 dogs in the LA group and 27/28 in the OA group survived to discharge (P = 0.810). Mean hospital stay was significantly shorter (P = 0.006) after LA (1.5 days, range 1-3) than after OA (2.2 days, range 1-4). No significant differences were demonstrated between LA and OA groups in recurrence of adrenal-dependent endocrine disease (P = 0.332), disease-free period (P = 0.733) and survival time (P = 0.353). The disease-specific 1-, 2- and 3-year survival rates were 95, 89, and 89% after LA and 92, 88, and 81% after OA. Tumor size was significantly associated with the occurrence of a recurrence. In addition, tumor size had a negative effect on the disease-free period and survival time. This study shows a favorable outcome of both LA and OA in dogs. Based on low perioperative complication rate, short hospitalization time and long-term outcomes comparable to OA in selected cases, the less invasive laparoscopic approach is considered the preferred technique.

Association between divisional location and short-term outcome of liver mass resection in 124 dogs

OBJECTIVE

To evaluate the association between divisional location of liver masses on short-term outcomes after surgical excision.

STUDY DESIGN

Retrospective case series.

ANIMALS

Client-owned dogs (n = 124).

METHODS

Records were reviewed for demographics, surgical findings, and outcomes. The associations between mass location and mortality, intraoperative complications, and postoperative complications were tested with multivariable logistic regression models.

RESULTS

Liver masses (124) were more common in the left (72) division than the central (34) and right (18) divisions. Median follow up was 286 (range: 14 to 2043) days. Intraoperative complications occurred in 14/124 dogs (11.3%) and postoperative complications in 35/122 dogs (28.7%). No association was detected between mass location and mortality in 8/124 dogs (6.5%). Postoperative complications were more likely if the incision extended to the thorax (P < .001), which was more common during resection of right divisional masses (P = .020). Postoperative complications were less likely when surgery was performed with a thoracoabdominal (TA) stapler (P = .005), by a specialist surgeon (P = .033), and in heavier dogs (P = .027). The odds of intraoperative complications were 19 times higher when surgery was performed without a TA stapler (P = .006). Intraoperative complications were less commonly associated with left (P = .007), but not central (P = .0504) divisional masses than right divisional masses.

CONCLUSION

Right divisional masses were prone to intraoperative but not postoperative complications.

CLINICAL SIGNIFICANCE

Clinicians should anticipate an increased risk of intraoperative complications when planning treatment of right divisional masses.

Prediction of vascular invasion using a 7-point scale computed tomography grading system in adrenal tumors in dogs

BACKGROUND

Previous studies evaluating the accuracy of computed tomography (CT) in detecting caudal vena cava (CVC) invasion by adrenal tumors (AT) used a binary system and did not evaluate for other vessels.

OBJECTIVE

Test a 7-point scale CT grading system for accuracy in predicting vascular invasion and for repeatability among radiologists. Build a decision tree based on CT criteria to predict tumor type.

METHODS

Retrospective observational cross-sectional case study. Abdominal CT studies were analyzed by 3 radiologists using a 7-point CT grading scale for vascular invasion and by 1 radiologist for CT features of AT.

ANIMALS

Dogs with AT that underwent adrenalectomy and had pre- and postcontrast CT.

RESULTS

Ninety-one dogs; 45 adrenocortical carcinomas (50%), 36 pheochromocytomas (40%), 9 adrenocortical adenomas (10%) and 1 unknown tumor. Carcinoma and pheochromocytoma differed in pre- and postcontrast attenuation, contralateral adrenal size, tumor thrombus short- and long-axis, and tumor and thrombus mineralization. A decision tree was built based on these differences. Adenoma and malignant tumors differed in contour irregularity. Probability of vascular invasion was dependent on CT grading scale, and a large equivocal zone existed between 3 and 6 scores, lowering CT accuracy to detect vascular invasion. Radiologists' agreement for detecting abnormalities (evaluated by chance-corrected weighted kappa statistics) was excellent for CVC and good to moderate for other vessels. The quality of postcontrast CT study had a negative impact on radiologists' performance and agreement.

CONCLUSIONS AND CLINICAL IMPORTANCE

Features of CT may help radiologists predict AT type and provide probabilistic information on vascular invasion.

Urinary free metanephrines measurement in dogs with adrenal gland diseases using a new simple liquid chromatography tandem mass spectrometry method

Measurement of urinary metanephrines in spot samples is used for the diagnosis of canine pheochromocytoma (PC). We describe a simple analytical method based on liquid chromatography tandem mass spectrometry (LC-MS/MS) for measuring free metanephrine (MN) and normetanephrine (NMN) in spot urine samples. Using the developed method, we evaluated the stability of urinary free-MN and free-NMN at various storing conditions. In addition, we assessed the feasibility of urinary free-MN and -NMN measurement for diagnosing PC. Urine samples were mixed with stable isotope internal standards and thereafter purified by ultrafiltration. The purified samples were analyzed by LC-MS/MS in the multiple reaction monitoring mode after separation on a multimode octa decyl silyl column. The coefficient of variation of free-MN and -NMN measurement was 7.6% and 5.5%, respectively. The linearity range was 0.5–10 µg/l for both analytes. Degradation was less than 10% for both analytes under any of the storage conditions. The median free-NMN ratio to creatinine of 9 PC dogs (595, range 144–47,961) was significantly higher (P<0.05) than that of 13 dogs with hypercortisolism (125, range 52–224) or 15 healthy dogs (85, range 50–117). The developed method is simple and may not require acidification of spot urine. The results of this preliminary retrospective study suggest that the measurement of urinary free metanephrines is a promising tool for diagnosing canine PC.