Perioperative morbidity and mortality in dogs with invasive adrenal neoplasms treated by adrenalectomy and cavotomy

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.

Preemptively planned en bloc resection of an extensive right adrenal pheochromocytoma involving the right hepatic division, caval thrombus and segmental caudal vena cava in a dog with Budd-Chiari-like syndrome

BACKGROUND

Surgical resection is the treatment of choice for canine adrenal pheochromocytomas (PHEOs). Information on en bloc resection of adrenal PHEO with tumour thrombus, right hepatic division and segmental caudal vena cava (CVC) running through the adrenal tumour and right hepatic division is limited.

OBJECTIVE

To describe the preemptively planned en bloc resection of an extensive right adrenal PHEO involving the right hepatic division, the caval thrombus and the segmental CVC in a dog with Budd-Chiari-like syndrome (BCLS).

METHODS

A 13-year-old castrated male miniature dachshund was referred for surgical treatment due to anorexia, lethargy and severe abdominal distension caused by abundant ascites. Preoperative computed tomography (CT) revealed a large mass in the right adrenal gland with a large caval thrombus obstructing the CVC and hepatic veins, which caused BCLS. Additionally, collateral vessels were formed between the CVC and azygos veins. No findings suggested obvious metastases. Based on CT findings, an en bloc resection of the adrenal tumour with caval thrombus, right hepatic division and segmental CVC was planned.

RESULTS

The preoperatively planned resection was feasible; the tumour was completely resected grossly. The operation time and total Pringle manoeuvre time were 162 min and 16 min 56 s, respectively. There was no postoperative hindlimb oedema, renal dysfunction, ascites or abdominal distention. The patient's clinical signs, including appetite, fully improved. Hospitalization lasted 16 days. However, the patient died on the 130th postoperative day due to suspected metastases and cachexia.

CONCLUSIONS

Even in case of an extensive infiltration of adrenal PHEO causing BCLS, an en bloc resection might be successfully achieved based on the preoperative CT findings speculating the collateral vessels formed for caudal venous return.

Stereotactic body radiation therapy as an alternative to adrenalectomy for the treatment of pheochromocytomas in 8 dogs

The objective of this report is to describe the use and outcome of stereotactic body radiation therapy (SBRT) for treatment of pheochromocytomas in 8 dogs. Pheochromocytomas are an uncommon but challenging tumour to manage. Adrenalectomy is the standard of care for treatment of pheochromocytomas in both animals and humans; however, unpredictable catecholamine secretion from the tumour and vascular and local invasion of the tumour and thrombi can pose life-threatening perioperative and anaesthetic risks. SBRT has been investigated as an alternative to adrenalectomy in human patients with pheochromocytomas. Eight dogs with clinical signs, an adrenal mass, and cytology and/or urine normetanephrine/creatinine ratios consistent with pheochromocytoma were treated with SBRT in lieu of adrenalectomy. Three dogs presented with acute hemoabdomen. Seven dogs had caval tumour invasion, 3 with extension into the right atrium. Following SBRT, all dogs had complete resolution of clinical signs and reduced urine normetanephrine/creatinine ratio and/or tumour size. No significant anaesthetic complications were encountered. Acute radiation toxicity was limited to grade I gastrointestinal signs in 3 dogs and resolved within 1-2 days of symptomatic therapy. Five of 8 dogs were alive at the time of follow up, with a median follow up time of 25.8 months. SBRT resulted in a favourable outcome and mitigated the life-threatening risks of adrenalectomy in these 8 dogs. SBRT may be a safe and effective alternative to adrenalectomy for pheochromocytomas in dogs with non-resectable tumours, or for owners averse to the risks of surgery.

Surgical findings and outcomes after unilateral adrenalectomy for primary hyperaldosteronism in cats: a multi-institutional retrospective study

CASE SERIES SUMMARY

Twenty-nine cats from different institutions with confirmed or highly suspected primary hyperaldosteronism treated by unilateral adrenalectomy were retrospectively included in this study. The most frequent clinical signs were lethargy (n = 20; 69%) and neck ventroflexion (n = 17; 59%). Hypokalaemia was present in all cats, creatinine kinase was elevated in 15 and hyperaldosteronism was documented in 24. Hypertension was frequently encountered (n = 24; 89%). Preoperative treatment included potassium supplementation (n = 19; 66%), spironolactone (n = 16; 55%) and amlodipine (n = 11; 38%). There were 13 adrenal masses on the right side, 15 on the left and, in one cat, no side was reported. The median adrenal mass size was 2 × 1.5 cm (range 1-4.6 × 0.4-3.8); vascular invasion was present in five cats, involving the caudal vena cava in four cats and the renal vein in one. Median duration of surgery was 57 mins. One major intraoperative complication (3%) was reported and consisted of haemorrhage during the removal of a neoplastic thrombus from the caudal vena cava. In 4/29 cats (14%), minor postoperative complications occurred and were treated medically. One fatal complication (3%) was observed, likely due to disseminated intravascular coagulation. The median duration of hospitalisation was 4 days; 97% of cats survived to discharge. The potassium level normalised in 24 cats within 3 months of surgery; hypertension resolved in 21/23 cats. Follow-up was available for 25 cats with a median survival of 1082 days. Death in the long-term follow-up was mainly related to worsening of comorbidities.

RELEVANCE AND NOVEL INFORMATION

Adrenalectomy appears to be a safe and effective treatment with a high rate of survival and a low rate of major complications. Long-term medical treatment was not required.

Balloon catheter as an extraction device for caudal vena cava adrenal tumor thrombectomy in a dog: A case report

OBJECTIVE

To report the use of a balloon catheter as an extraction device for a posthepatic caval thrombus in a dog with a right adrenal tumor.

ANIMALS

Twelve-year-old male neutered Chihuahua mix dog.

STUDY DESIGN

Case report METHODS: The dog presented for the evaluation of a hepatic mass. Computed tomography of thorax and abdomen was performed, and a right lateral liver lobe mass and a right adrenal mass were noted. The adrenal mass had a caval thrombus extending almost to the level of the right atrium. Traditional methods of tumor thrombectomy were unsuccessful. Extraction of the thrombus was facilitated by passing a balloon catheter through the caudal vena cavotomy until it was cranial to the thrombus, inflating the balloon and slowly withdrawing the catheter.

RESULTS

A malignant pheochromocytoma was diagnosed on histology. The dog had a subjectively assessed good quality of life until it was euthanized 118 days postoperatively for acute dyspnea.

CONCLUSION

Balloon catheter-assisted thrombectomy was successful in removing an extensive caval thrombus that was otherwise difficult to extract via conventional methods. This technique can be considered in cases with extensive tumor thrombus either as a method of choice or when other methods of thrombus extraction have failed.

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.

Short- and long-term survival after adrenalectomy in 53 dogs with pheochromocytomas with or without alpha-blocker therapy

OBJECTIVE

To report data related to the short- and long-term survival of dogs undergoing adrenalectomy for pheochromocytoma, and to determine the influence of preoperative alpha-blocker therapy.

STUDY DESIGN

Retrospective.

ANIMALS

Fifty-three dogs.

METHODS

Medical records were reviewed for dogs diagnosed with pheochromocytoma and treated with adrenalectomy between 2010 and 2020. Preoperative management, imaging studies, intraoperative cardiovascular instability, complications, and procedural information were recorded. When applicable, duration of survival and cause of death, time to recurrence or metastasis, and postoperative complications were recorded.

RESULTS

During anesthesia, a hypertensive episode was documented in 46/53 dogs and arrhythmias were recorded in 16/53 dogs. Of these, 37/46 hypertensive dogs and 11/16 dogs with arrhythmias were treated with an alpha-blocker before surgery. Intraoperative systolic blood pressures reached higher levels by a magnitude of nearly 20% in dogs that were treated preoperatively with an alpha-blocker (P = .01). All dogs survived surgery and 44 survived to discharge. Follow up ranged from 6 to 1653 days (median 450 days). Median survival time for dogs discharged from the hospital was 1169 days (3.2 years). Recurrence and metastasis were suspected in 3 and 8 dogs, respectively.

CONCLUSION

Most dogs survived the immediate postoperative period and achieved long-term survival with a low reported incidence of tumor recurrence or metastasis. Preoperative alpha-blocker therapy was not associated with increased survival.

CLINICAL SIGNIFICANCE

The favorable outcomes reported in this study should be taken into consideration when discussing treatment options for dogs with pheochromocytomas. This study provides no evidence to support preoperative alpha-blocker therapy.

18F-FDG PET/CT image findings of a dog with adrenocortical carcinoma

Background

In human medicine, 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has been used to differentiate between benign and malignant adrenal tumors and to identify metastases. However, canine adrenocortical carcinomas identified by 18F-FDG PET/computed tomography (CT) have not been reported.

Case presentation

A 13-year-old, castrated male, Cocker Spaniel dog with severe systolic hypertension exhibited an adrenal mass approximately 3.6 cm in diameter on ultrasonography. There was no evidence of pulmonary metastasis or vascular invasion on thoracic radiography and abdominal ultrasonography, respectively. 18F-FDG PET/CT was performed to identify the characteristics of the adrenal mass and the state of metastasis. One hour after injection of 5.46 MBq/kg 18F-FDG intravenously, the peripheral region of the adrenal mass visually revealed an increased 18F-FDG uptake, which was higher than that of the liver, and the central region of the mass exhibited necrosis. The maximal standardized uptake value (SUV) of the adrenal mass was 3.24; and relative SUV, calculated by dividing the maximal SUV of the adrenal tumor by the mean SUV of the normal liver, was 5.23. Adrenocortical carcinoma was tentatively diagnosed and surgical adrenalectomy was performed. Histopathologic examination of the resected adrenal mass revealed the characteristics of an adrenocortical carcinoma. After adrenalectomy, systolic blood pressure reduced to below 150 mmHg without any medication.

Conclusion

This is the first case report of 18F-FDG PET/CT findings in a dog with suspected adrenocortical carcinoma and may provide valuable diagnostic information for adrenocortical carcinoma in dogs.

Renal venotomy for thrombectomy and kidney preservation in dogs with adrenal tumors and renal vein invasion

OBJECTIVE

To describe the surgical technique and report the outcomes of adrenalectomy and thrombus removal with kidney preservation by renal venotomy in a population of dogs with adrenal tumors and vascular invasion into the renal vein (RV) and caudal vena cava (CVC).

STUDY DESIGN

Short case series.

ANIMALS

Five client-owned dogs that underwent adrenalectomy.

METHODS

Dogs with adrenal tumors and vascular invasion into the RV and CVC were retrospectively enrolled in this multi-institutional study. Renal venotomy was performed at the time of adrenalectomy for tumor thrombus removal. Recorded data included signalment, clinical signs and results of laboratory testing, physical examination findings, diagnostic imaging results, surgical technique, surgical time, surgical complications, and outcome.

RESULTS

Tumor thrombus was removed by renal venotomy in five dogs. In one dog with an ectopic adrenal tumor located ventral to the left kidney, the thrombus was occluding 90% of caval flow, and a small caval venotomy was required to remove it. Kidney preservation was achieved in all dogs. No significant intraoperative or postoperative complications occurred, and all dogs were discharged 3 to 4 days postoperatively. Median surgical time was 125 minutes (range, 80-210). At the end of the study, four dogs were alive without signs of recurrence, while one dog died of a suspected pulmonary embolism at 510 days. Median follow-up was 510 days (range, 279-890).

CONCLUSION

Renal venotomy is feasible for thrombectomy in dogs with adrenal tumors and RV invasion and allowed for the preservation of the kidney in this case series, thus limiting perioperative morbidity.

A comparison of outcomes between laparoscopic and open adrenalectomies in dogs

OBJECTIVE

To compare short- and long-term outcomes of dogs with adrenal tumors treated by adrenalectomy with laparoscopy or laparotomy.

STUDY DESIGN

Retrospective study of dogs that underwent adrenalectomy with laparoscopy or laparotomy.

SAMPLE POPULATION

Fourteen dogs treated with laparoscopic adrenalectomy (LA) and twenty-six dogs treated with open midline adrenalectomy (OA).

METHODS

Dogs treated with LA were matched with 1 or 2 dogs treated with OA on the basis of histological nature, size, and side of the tumor. Intraoperative complications, postoperative complications, and long-term survival were compared between LA and OA.

RESULTS

Intraoperative hypotension occurred in 2 of 14 (14.3%) dogs in the LA group and in 16 of 26 (61.5%) dogs in the OA group (P = .007). The surgical time was 69.8 ± 21.8 minutes for the LA group and 108.6 ± 42 minutes for the OA group (P = .0003). The hospitalization time was 39.3 ± 14.9 hours for the LA group and 46.3 ± 25.1 hours for the OA group (P = .1453). The 1- and 2-year survival rates were 77% and 77%, respectively, for the LA group and 77% and 66%, respectively, for the OA group (P = .6144).

CONCLUSION

Laparoscopic adrenalectomy was associated with a shorter surgical time and a reduced incidence of hypotension compared with open adrenalectomy in this case-matched study. Short- and long-term outcomes were not affected by the surgical technique used to complete the adrenalectomy.

CLINICAL SIGNIFICANCE

Laparoscopy can be recommended for adrenalectomy in dogs; however, appropriate case selection is required.

Use of Contrast-Enhanced Ultrasonography for the Characterization of Tumor Thrombi in Seven Dogs

Simple Summary

Some neoplasia—such as adrenal and thyroid glands tumors—have been associated with “tumor thrombi” both in humans and dogs. The detection and characterization of these venous tumor thrombi is important for both surgical planning and prognosis. In human medicine, contrast-enhanced ultrasonography (CEUS) is considered an accurate diagnostic technique for differentiating malignant from benign portal vein thrombosis in hepatocellular carcinomas. Data regarding the characteristics of tumor thrombi in dogs are currently lacking. Therefore, the aim of this study was to assess the feasibility of CEUS for the characterization of malignant venous thrombosis in dogs. On the basis of our results, CEUS appeared to be useful in the detection of malignant intravascular invasion; contrast uptake of the thrombus was present in all cases. In addition, CEUS may clearly detect newly formed vessels within the thrombus, and arterial-phase enhancement and washout in the venous phase were the main features in malignant thrombosis in our dogs. As CEUS is an easy to perform, noninvasive technique, its application in the detection of malignant thrombosis in dogs may be used to improve the diagnosis in oncological canine patients.

Abstract

Tumors of adrenal and thyroid glands have been associated with vascular invasions—so-called tumor thrombi, both in humans and dogs. The detection and characterization of venous thrombi is an important diagnostic step in patients with primary tumors for both surgical planning and prognosis. The aim of this study was to describe the use of contrast-enhanced ultrasonography (CEUS) for the characterization of tumor thrombi. Dogs with tumor thrombus who underwent bi-dimensional ultrasound (B-mode US) and CEUS were included. Seven dogs were enrolled in this retrospective case series. On B-mode US, all thrombi were visualized, and vascular distension and thrombus-tumor continuity were seen in three and two cases, respectively. On color Doppler examination, all thrombi were identified, seemed non-occlusive and only two presented vascularity. On CEUS, arterial-phase enhancement and washout in the venous phase were observed in all cases. Non-enhancing areas were identified in the tumor thrombi most likely representing non-vascularized tissue that could potentially be embolized in the lungs after fragmentation of the tumor thrombi. On the basis of these preliminary study, CEUS appeared to be useful for the characterization of malignant intravascular invasion.

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

Veterinary studies have reported the outcome of adrenalectomies in dogs; however, these studies typically include a wide variety of adrenal tumour sizes, including cases with or without vascular invasion. The purpose of this study was to report outcome in a cohort of dogs with histologically confirmed small adrenal tumours without vascular invasion treated with adrenalectomy. This retrospective study was conducted using data from the University of Florida and University of California-Davis databases between 2010 and 2017. Dogs were included if they underwent excision of an adrenal gland tumour with a maximal diameter ≤ 3 cm, without evidence of vascular invasion to any location as assessed via computed tomography. Fifty-one dogs met the inclusion criteria. The short-term survival rate of dogs undergoing adrenalectomy was 92.2%, and one-year disease-specific survival was 83.3%. Twenty-eight of 51 (54.9%) dogs were diagnosed with a malignancy. Minor complications were observed commonly intra-operatively and post-operatively. Major complications were observed in six dogs, and included sudden death, respiratory arrest, acute kidney injury, haemorrhage, hypotension and aspiration pneumonia. Short-term mortality occurred in four dogs. Sudden death and haemorrhage were the most common major complications leading to death. While adrenalectomy is sometimes controversial because of the high perioperative mortality rates previously reported, the results of this study support that adrenalectomy for small tumours with no vascular invasion can be performed with low risk.