Definitive Chemoradiation with Concurrent Carboplatin and Paclitaxel for HPV-Mediated Oropharyngeal Cancer (p16+ OPSCC): Survival and Local Control

PURPOSE/OBJECTIVE(S)

Standard therapy for locally advanced p16+ OPSCC with cisplatin and bilateral nodal RT results in substantial acute and late toxicities. De-intensification strategies are under active investigation, including the de-escalation of RT dose and field size and use of less toxic RT sensitizing agents. We present our single-institution experience with definitive chemoRT using weekly carboplatin and paclitaxel and modified RT.

MATERIALS/METHODS

A retrospective review of 139 consecutive patients with non-metastatic p16+ OPSCC treated with definitive chemoRT from 2013 to 2019 was performed. IMRT dose ranged from 60 to 70 Gy (median 69.96 Gy) to gross disease and 44 to 59.4 Gy (median 54.45 Gy) to elective nodal sites. Modified RT included dose reduction from 70 Gy EQD2 to 60-67.8 Gy EQD2 (2.0-2.2 Gy/fraction) and/or field modified contralateral neck. All patients received concurrent weekly paclitaxel (30 mg/m2) and carboplatin (AUC 1); 34 (24.5%) received induction chemotherapy. Patients were classified as low or intermediate risk based on HPV status, smoking history, and nodal staging per RTOG 0129 risk stratification. OS, local and regional RFS, and DSS were estimated using Kaplan-Meier method.

RESULTS

Median FU was 40.5 months. Of 139 pts, 96 were low and 43 were intermediate risk. Median age 61 yrs (range, 40-81 yrs). 125 pts were male and 14 were female. TNM staging: 29 pts (20.9%) were T1 (22 N1, 7 N2), 68 (48.9%) T2 (4 N0, 52 N1, 12 N2), 27 (19.4%) T3 (5 N0, 15 N1, 7 N2), and 15 (10.8%) T4 (2 N0, 2 N1, 10 N2, 1 N3). Median smoking history of 22.5 pack-yrs (range, 0.25-150 pack-yrs); 59 never smoked. LR recurrence was noted in 6/96 (6.3%) low risk and 7/43 (16.3%) intermediate risk pts. DM developed in 11/96 (11.5%) low risk and 8/43 (18.6%) intermediate risk pts. Synchronous LR recurrence and DM were noted in 1/96 (1%) low risk and 2/43 (4.7%) intermediate risk pts. The 3-year LRC was 93.6% (95% CI, 86.3-97.1) in the low-risk and 77.8% (95% CI, 61.4-87.8) in the intermediate-risk group. The 3-year OS was 95.4% (95% CI, 88.3-98.3) in the low-risk and 77.6% (95% CI, 61.3 to 87.7) in the intermediate-risk group. The 3-year DSS was 96.6% (95% CI, 89.7-98.9) in the low-risk and 86.8% (95% CI, 71.0-94.3) in the intermediate-risk group.

CONCLUSION

Definitive chemoRT for p16+ OPSCC with concurrent carboplatin and paclitaxel and a modified RT regimen designed to minimize acute and late effects of therapy demonstrated comparable outcomes to standard cisplatin-based chemoRT, such as report on RTOG 0129, with a high rate of LRC at 3 years. Our analysis suggests a role for a less intensive regimen using paclitaxel and carboplatin as a less toxic, effective alternative to cisplatin in the curative management of p16+ OPSCC, particularly in low-risk patients. Strategies for combating distant metastases are needed. Toxicity analysis planned to be presented separately.

Tailoring Radiation to the Contralateral Neck for Midline HPV-Mediated Oropharyngeal Squamous Cell Carcinoma (p16+ OPSCC)

PURPOSE/OBJECTIVE(S)

De-intensification strategies for locally advanced p16+ OPSCC are under active investigation, including omission of contralateral neck radiation (RT) for well-lateralized T1-2N0-2a. This study evaluates the outcomes of omitting contralateral neck nodal levels for p16+ OPSCC that are not well-lateralized.

MATERIALS/METHODS

A retrospective review was done of 134 consecutive patients with non-metastatic p16+ OPSCC that were not well-lateralized (< 1 cm from midline or ≥ 1 cm extension to soft palate or base of tongue) who were treated with definitive chemoradiation from 2013 to 2019. IMRT to an EQD2 6364-6735 cGy (200-220 cGy per fraction) was used to treat the primary tumor and ipsilateral or bilateral neck, with tailored nodal level coverage and dose, and with concurrent paclitaxel and carboplatin. Contralateral neck RT was tailored in 121 patients: omitted in 11, limited to level II in 9, and limited to level II and III in 101 (contralateral lower neck omitted); the remaining 13 had bilateral level II-IV neck RT. Local and regional recurrences were evaluated.

RESULTS

Median follow up was 45.34 months. Local and/or regional recurrence was noted in 9/134 (6.7%). 3 (2%) recurred in the contralateral neck in unirradiated tissue (out-of-field). All three were salvaged. The remaining 6 recurrences (4%) were in-field; one was at the primary site and 5 were nodal (all ipsilateral). 4 of the 5 regional recurrences were in a location that was treated to EQD2 7000 cGy (all had PET avid nodal disease upfront that was included in the high dose level); the other region of recurrence was treated to an EQD2 6353 cGy (the only recurrence in a never smoker). 4 of the 5 neck recurrences underwent neck dissection; one further underwent adjuvant RT to 5940 cGy in 33 fractions and remains disease-free. 2 of those who underwent salvage neck dissection alone subsequently developed distant metastases. The majority of first recurrences were distant, 19.4% (26/134). 3-year progression free survival (PFS) was 74.41% (95% CI, 65.63-81.26). Taken together, regional recurrence rate in the contralateral, unirradiated neck was 2.5% (3/121) and ultimate locoregional control was 99% (132/134).

CONCLUSION

Our tailored approach demonstrates a contralateral neck local control of 97.5% (118/121) regardless of tumor lateralization; those who recurred in unirradiated cervical lymph nodes were successfully salvaged. Limiting this analysis is moderate sample size and retrospective nature, but it raises important alternative de-escalation strategies (RT volume reduction) for p16+ OPSCC aside from dose reduction, which is under active investigation in phase II/III trials. Improved systemic therapies are needed to combat distant metastases. Prospective randomized clinical trials are needed for further evaluation of nodal omission for definitive chemoradiation of non-well-lateralized p16+ OPSCC.

128 TO BLEED OR NOT TO BLEED: THE INTRACEREBRAL HAEMORRHAGE MANAGEMENT QUESTION

Background

Intracerebral Haemorhage (ICH) accounts for 9-27 per cent of all strokes. There are high rates of early case fatality and poor functional outcome. Clear guidelines and pathways exist around the management of ischaemic stroke. Pathways for the haemorrhagic stroke patient are lacking. Good evidence exists for early Blood Pressure (BP) management, reversal of Oral Anti-Coagulation (OAC) and admission to a Hyper-Acute Stroke Unit (HASU) in terms of improving outcomes.

Methods

A retrospective cohort analysis was performed, looking at all the presentations with ICH over one calendar year. The factors measured included time to CT Brain, BP at presentation, documented target systolic BP of under 140mmHg, time to treatment of hypertension, number on OAC, OAC reversal, time to OAC reversal, admission to HASU. The findings were compared to standards outlined in the European Stroke Organisation and American Heart Association’s ICH management guidance.

Results

76 patients were include (40 female). Mean age was 73, age range 34-93. median age 77. 44 were hypertensive on admission (20 info unavailable [u/a]). Of the 44, 34 had a documented target BP under 140mmHg (12 = n/a, 20 u/a). Time to treatment of hypertension was within 60 minutes for 3 patients. Of those that were hypertensive, 57 per cent were 75 or younger. 16 were on an OAC, of which 11 were appropriately reversed (3 u/a). Of the 11, 2 were reversed within 90 mins (7 u/a). Of those on an OAC, 75 per cent were over 75. 32 were admitted to HASU within 72h (all of these made it within 24h), (10 did not reach HASU, 3 reached HASU bed after 72h, 31 u/a).

Conclusion

Management of ICH is variable and suboptimal. Our goal is to produce a written pathway which will be incorporated into our hyperacute stroke document, with a plan to re-audit.

Results from a phase 1 multiple ascending dose study demonstrating safety and selectivity of aldosterone synthase inhibitor CIN-107

Background

CIN-107 is a highly potent, selective, and competitive small molecule inhibitor of aldosterone synthase that is a potential treatment for disorders associated with elevated aldosterone levels, including hypertension and primary aldosteronism. This randomized, double-blind, placebo-controlled phase 1 study evaluated the safety, pharmacokinetics, and pharmacodynamics of multiple ascending doses of CIN-107 in healthy volunteers.

Methods

Subjects were randomized into 5 cohorts to receive CIN-107 or placebo once daily for 10 days. Cohorts 1 and 2 were placed on a low salt diet to stimulate aldosterone production and were administered 2.5 or 5.0 mg oral CIN-107, respectively. Cohorts 1 and 2 also underwent an adrenocorticotropic hormone (ACTH) challenge to increase aldosterone and cortisol levels to evaluate the specificity of CIN-107 for targeting aldosterone synthase. Cohorts 3, 4, and 5 were placed on a normal salt diet and were administered 1.5, 2.5, or 0.5 mg oral CIN-107, respectively. Blood samples were collected prior to and after dosing on days 1 and 10 for measurement of plasma CIN-107 concentrations to characterize single-dose and steady-state pharmacokinetics. Pharmacodynamic measurements included plasma aldosterone, cortisol, and electrolytes. Safety assessments included physical examination, electrocardiograms, orthostatic vital signs, and clinical laboratory evaluations.

Results

54 subjects completed the study. There were no deaths, serious adverse events, or discontinuations due to treatment-emergent adverse events (TEAEs). All TEAEs in subjects receiving CIN-107 were mild in severity (Table 1). Plasma concentrations of CIN-107 increased proportionally with ascending doses. CIN-107 was rapidly absorbed, with peak concentrations observed within 4 hours after dosing. The concentration of plasma CIN-107 declined in an apparent biphasic manner with a half-life of 26 to 31 hours. A dose-dependent reduction of plasma aldosterone was observed with CIN-107 doses ≥1.5 mg, regardless of normal or low salt diet. Decreases in plasma aldosterone were observed starting on Day 1 and were sustained, with levels reduced by approximately 51–73% on Day 10 (Figure 1). The inhibition of aldosterone synthase by CIN-107 had no impact on plasma cortisol. CIN-107 resulted in mild dose-dependent decreases in plasma sodium levels and increases in potassium levels, as would be expected from the observed reduction in aldosterone.

Conclusions

Oral administration of CIN-107 was safe and well tolerated in all subjects and resulted in dose-dependent increases in plasma CIN-107 with a half-life that supports once-daily dosing. The dose-dependent decrease in plasma aldosterone and lack of effect on cortisol demonstrate the selective blockade of aldosterone synthase and support continued study in ongoing phase 2 clinical trials evaluating the efficacy and safety of CIN-107 for treatment-resistant or uncontrolled hypertension and primary aldosteronism.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): CinCor Pharma Inc

994 The Evolving Role of Interventional Radiology in the Management of Diverticular Abscesses: A Review of Practice at University Hospital Waterford Over 10 Years

Background

Historically, intra-abdominal sepsis was managed conservatively, or with operative intervention, which is associated with significant morbidity and mortality. Image-guided drainage of abscesses or collections provides a useful alternative and has become more common with the increasing prominence of Interventional Radiology, offering faster recovery, reduced length of hospital stay and cost of treatment. Modern procedural tools, techniques and expertise allow high levels of percutaneous drainage success. The scope of practice has widened to include targets which previously wouldn't have been amenable to drainage.

Aim

To quantify the use and benefit of IR drainage for complicated diverticulitis at University Hospital Waterford over the past ten years. The size and location of collections drained throughout the ten years was observed. Length of hospital stay for each mode of management (conservative, percutaneous drainage and surgical) was used as an endpoint to assess morbidity.

Method

Using NIMIS, all CT abdomen/pelvis reports containing the words “abscess” or “collection”, and “diverticul” over the past 10 years was compiled. These patients were categorised by their management, into groups of conservatives, percutaneous drainage, surgical intervention, or a combination of these. NIMIS was used to determine who underwent IR drainage. T-pro, theatre logbooks and patient notes were used to determine who had surgical management, and iPMS was used to assess length of hospital stay.

Results

IR drainage has become more common year-on-year in UHW and was shown to be more effective for all abscess sizes as compared with conservative management, as outlined in the table shown

The Effect of COVID-19 on 30-Day Mortality Rates Amongst Fragility Hip Fracture Patients

Aim Fragility hip fracture patients have always been vulnerable to high rates of short term mortality, an issue that may have been exacerbated by the ongoing COVID-19 pandemic. To date, published data regarding Irish hip fracture patients in the era of COVID-19 is limited. This study aims to assess the effect of COVID-19 on 30-day mortality rates amongst a group of Irish hip fracture patients. Additionally, patient demographics, length of stay, admission haematological parameters, fracture type and surgical procedure will be assessed. Methods A multicentre, observational, retrospective study of hip fracture patients (n = 1,017) admitted to six Dublin teaching hospitals during the COVID-19 pandemic (4th February to 9th July 2020) was performed. For comparative purposes, equivalent data was retrospectively collected relating to hip fracture patients admitted to the same six teaching hospitals during the same time period in 2019. Results 481 patients were admitted during the specified timeframe in 2020, compared with 536 in 2019. The mean patient age was 77.6 years and 65.9% of patients were female. There was no statistically significant overall difference in 30-day mortality rates between the study and control groups, at 5.4% in 2020 and 4.3% in 2019 (p=0.338). There was an insignificant decrease in mean length of stay (17.85 days in 2020 vs. 18.82 days in 2019; p=0.106). Advancing age (p=0.021), male gender (p=0.019), low admission haemoglobin (p=0.024) and high admission white cell count (p=0.019) were all associated with increased 30-day mortality. Conclusion We found no significant difference in 30-day mortality rates amongst our cohort of hip fracture patients at the height of the COVID-19 pandemic in Ireland. Advancing age, male gender, anaemia at admission and leucocytosis at admission were associated with increased 30-day mortality. The continuation of COVID-19 related safety protocols in the treatment of hip fracture patients is essential in maintaining a safe hip fracture service.

Infrared thermographic assessment of spinal anaesthesia-related cutaneous temperature changes during caesarean section

INTRODUCTION

Assessment of adequacy of spinal anaesthesia prior to obstetric surgery is extremely important but can be problematic because currently available clinical assessment methods are indirect and subjective. As the sympathectomy associated with spinal anaesthesia is known to cause vasodilation and heat redistribution, we sought to assess whether spinal anaesthesia led to significant and consistent cutaneous temperature changes as measured by infrared thermography.

METHODS

Following ethics committee approval, this observational study was conducted in a tertiary level obstetric centre. Participants included women undergoing elective caesarean section under spinal anaesthesia. Following consent, a Flir T540 infrared camera captured thermographic images over the feet, patella, buttock, iliac crests, xiphisternum and axilla. Temperature was measured prior to spinal needle insertion (T0) and following clinical assessment when the block was deemed adequate.

RESULTS

Thirty patients were included. Baseline temperature varied considerable by site. Spinal anaesthesia altered skin temperature in all areas of interest: right and left hallux (mean of differences (MD) +4.0°C and 5.2°C respectively, P <0.0001), right and left plantar (MD +6.1°C and 6.8°C respectively, P <0.0001), patella (MD -0.33°C, P=0.0445), buttock (MD -0.5°C, P=0.009), iliac crest (MD -0.7°C, P=0.0004), xiphisternum (MD -0.95°C, P <0.0001) and axilla (MD -0.71°C, P=0.0002).

CONCLUSIONS

Following spinal anaesthesia thermographic imaging identified different patterns of skin temperature changes, with pronounced temperature increases measured in the feet and cooling of a lesser amplitude in the thoracic and lumbar dermatomes. Infrared thermography has the potential to provide objective measurement of sympathectomy.

Successful treatment of a pregnant mother with dupilumab therapy for severe atopic dermatitis throughout pregnancy

Systemic treatment options for moderate to severe atopic dermatitis in pregnant patients are significantly limited due to safety concerns and a lack of evidence. We read with interest the case series published by Bosma et al.¹ We present a female who continued uninterrupted dupilumab for atopic dermatitis from conception throughout pregnancy delivering a healthy baby boy at full term. This healthy baby boy was born at term; mum and baby were discharged home on the day of delivery without complication.

A Series of Novel, Highly Potent, and Orally Bioavailable Next-Generation Tricyclic Peptide PCSK9 Inhibitors

Proprotein convertase subtilisin-like/kexin type 9 (PCSK9) is a key regulator of plasma LDL-cholesterol (LDL-C) and a clinically validated target for the treatment of hypercholesterolemia and coronary artery disease. Starting from second-generation lead structures such as 2, we were able to refine these structures to obtain extremely potent bi- and tricyclic PCSK9 inhibitor peptides. Optimized molecules such as 44 demonstrated sufficient oral bioavailability to maintain therapeutic levels in rats and cynomolgus monkeys after dosing with an enabled formulation. We demonstrated target engagement and LDL lowering in cynomolgus monkeys essentially identical to those observed with the clinically approved, parenterally dosed antibodies. These molecules represent the first report of highly potent and orally bioavailable macrocyclic peptide PCSK9 inhibitors with overall profiles favorable for potential development as once-daily oral lipid-lowering agents. In this manuscript, we detail the design criteria and multiparameter optimization of this novel series of PCSK9 inhibitors.

79 SIMULATION-BASED MEDICAL EDUCATION: A ‘HIP’ WAY TO LEARN ABOUT ORTHO-GERIATRICS!

Background

Simulation-based medical education (SBME) is emerging as a key method of medical education, particularly in the setting of the COVID-19 pandemic. As part of a simulation development competition (SimStars) run by the National Doctors Training and Planning Unit and the South–South West Hospital Group, we brought together an inter-disciplinary team to develop a simulation scenario on hip fracture.

Methods

Our development team consisted of members of the Geriatric Medicine and Orthopaedic Departments. We developed a scenario that can be adapted to suit the needs of learners in orthopaedics, medicine, or nursing. We ran the simulation on a medical ward with one candidate and four facilitators from the Geriatric Medicine Department. The candidate (medical SHO) was presented with a patient (facilitator one), who had sustained a hip fracture following a fall. The candidate was directed to elicit a falls and bone health history, screen for delirium, and suggest further investigations and management. Subsequently, feedback was sought from all participants.

Results

The simulation took twenty minutes, debriefing took fifteen minutes. All considered, the simulation an enjoyable and feasible method for teaching and learning, and a novel way to promote team-building. The candidate felt competent in some areas, reporting that the scenario provided positive reinforcement. She reported feeling supported in identifying areas for further learning. The facilitators also considered this method a useful way to highlight a candidate’s learning needs and direct further teaching. The candidate requested further SBME-based sessions.

Conclusion

This SBME session in Ortho-Geriatrics was well-received by the candidate and facilitators. All participants enjoyed teaching and learning through this medium. Areas of high competency were reinforced and areas for future learning were identified. Further SBME was requested across more topics and for simulation training to be brought in as part of formal training.

1235 A Multi-Site Review of Second Hip Fractures Across 6 Dublin Teaching Hospitals

Introduction

Hip fractures are a common presentation to Irish hospitals with 3,701 hip fractures recorded by 16 hospitals in the Irish Hip Fracture Database (IHFD) in 2019. Second hip fractures (HF2) make up a significant proportion of hip fractures and represent an opportunity to prevent subsequent fragility fracture.

Method

Hip fracture datasheets from 2019 in six Dublin hospitals were analysed.

Results

1,284 hip fractures in total were recorded in 2019 in these six hospitals. 112 of these were second hip fractures (8.72%). 24.1% of patients had a HF2 in year 1 post their first hip fracture (HF1). 14.3% of patients had a HF2 in Year 2, 8% in Year 3, 8.9% in Year 4 and 6.3% in Year 5. 17.9% of patients had an HF2 at an unknown time in relation to their HF1. 57.6% of all patients with any hip fracture were started on bone protection medications (BPMs) during their admission. 18.9% continued a pre-admission prescription. 7% of all patients were previously assessed and determined not to require BPM. 6.9% of patients were awaiting outpatient department (OPD) assessment for bone protection. 8.6% had no assessment for bone protection conducted. Of all patients with an HF2, 48.2% were started on BPMs on admission with their HF2. 33% continued BPMs started pre-admission.

Discussion

In 2019, approximately 1 in 10 hip fractures were second hip fractures. Evidence suggests that fracture liaison services represent a viable, economic means of preventing second hip fractures to improve patient outcomes and reduce healthcare expenditure.

1256 Orthopaedics and The COVID19 Pandemic: Was Achilles Just A “Weekend Warrior”?

Background

The COVID19 pandemic has affected the types of trauma being operated on by Orthopaedic surgeons. Lifting of restrictions pertaining to sports saw a sudden return to play for many people after a period of inactivity. Achilles tendon ruptures are associated with these episodic athletes. In our institution, we appeared to have a large number of these injuries within a short space of time. We hypothesised that Phase 3 of “Lockdown”, where all sports were allowed to return, led to increased Achilles tendon rupture rates vs. the same period in 2019 due to a prolonged period of inactivity.

Method

Data from electronic theatre logbooks of all operations performed in the trauma theatre from 27th March 2020 (Lockdown begins) to 31st July 2020 and 27th March 2019 to 31st July 2019 was collected.

Results

772 cases were performed in 2019. There were 17 Achilles tendon ruptures in that period (2.2%). 14 of these occurred after Phase 3. 555 cases were performed in 2020. There were 13 Achilles tendon ruptures in that period (2%). 11 of these occurred after Phase 3.

Conclusions

Overall, there was a greater number and greater rate of Achilles tendon ruptures in 2019 vs. the equivalent “Lockdown” period in 2020. 8 of the 11 occurring after Phase 3 in 2020 occurred in the month of July. This led the authors to believe they were occurring more frequently. In conclusion, the COVID19 pandemic restrictions and subsequent return to play after inactivity does not increase the rate of Achilles tendon rupture.

1244 The TAL Suction Retractor: A Simple Technique for Visualising the Transverse Acetabular Ligament (TAL) During Total Hip Replacement (THR) Surgery

Introduction

The transverse acetabular ligament (TAL) is an anatomical landmark that is of particular use during primary total hip replacements (THR). Visualisation is important to aid the orientation of the acetabular cup and it is a structure that can be identified in virtually every primary hip replacement surgery. We introduce a simple technique to facilitate this.

Method

A thoracic suction catheter is taped to the distal end of a blunt Hohmann’s retractor with two steristrips wrapping around the catheter and retractor leaving approximately 1-1.5cm of retractor exposed. Our preference is for a thoracic suction catheter with side holes and a proximal end which allows direct connection with the tip of the Yankauer suction. The blunt Hohmann’s retractor is used as the inferior acetabular retractor in the usual way, placed inferior to the transverse acetabular ligament, resting on the posterior ischial surface. The catheter suction tip should lie just under the TAL, in the most dependant point of the wound.

Results

The TAL suction catheter can be used continuously or intermittently to facilitate visualisation of the TAL during reaming, trialling, and acetabular cup placement. The TAL suction retractor provides suction in the most dependant point of the surgical wound, preventing unnecessary movement and facilitates a clutter-free surgical field leading to more streamlined and efficient surgery with potential reduced operative times.

Conclusions

The transverse acetabular ligament (TAL) suction retractor is a simple improvised surgical tool that makes it easier to visualise the TAL during acetabular preparation in total hip replacements.

56 ‘A Closed-Loop Audit on The Appropriateness of Urine Testing Carried Out on Surgical Patients in The Acute Surgical Unit in University Hospital Limerick as Compared with Hospital Guidelines’

Aim

The acute surgical unit (ASU) in University Hospital Limerick (UHL) has a high turnover of patients of all surgical specialties, many of whom are sent home without the need for admission or follow-up. Urinalysis is very accessible, and is carried out on many patients, prior to them being seen by a doctor. Inappropriate urinalysis sets off a cascade of inappropriate urine culture, antimicrobial treatment and a waste of resources and time of nursing, medical and laboratory staff. We aim to identify and reduce inappropriate testing.

Method

The notes of all ASU patients during a one-week period were analysed using the ‘Therefore Navigator’ application, where all patient notes are scanned on leaving the ASU. Data relating to presenting complaint, presence or absence of urinary symptoms and abdominal pain, and urine dipstick and culture results (if performed) was collected for each patient. The results were compared with UHL guidelines on testing, an information sheet was designed and placed in ASU, and an education session for nursing staff was carried out. The second cycle was performed one month later.

Results

In the first cycle, 68% of the 99 ASU patients had urinalysis, and 48% had urine culture performed. Of cultures performed, only 23 of 47 (49%) were deemed indicated according to the guidelines. In the second cycle, 39% had urinalysis. 28% had urine cultured, 79% of these were deemed to have been indicated.

Conclusions

Inappropriate urine testing in the ASU decreased following teaching for nursing staff, together with an information leaflet being placed in the ASU.

Differential inflammatory profile of mesenteric and omental fat in patients with colorectal cancer

Visceral obesity (mesenteric and omental adipose tissue) is a risk factor for colorectal cancer (CRC) and weight loss can reduce risk. This study examined mesenteric and omental fat activity in patients with CRC.

O71: INTRA-OPERATIVE SPINAL CORD MONITORING DURING SPINAL SURGERY: DOES IT HAVE ANY CLINICAL VALUE?

Introduction

Spinal cord surgery is a technically challenging endeavour with potentially devastating complications for patients and surgeons. Spinal cord monitoring (SCM), is one method of preventing and identifying damage to the spinal cord. At present, indications for its use are based more on individual surgeon preference and for medico legal purposes. Our study aimed to determine SCM's utility as a clinical tool.

Method

This is a retrospective case series of 169 patients who underwent spinal surgery with SCM at two institutions between 2013 and 2018. Signal changes detected were recorded as well as the surgeon's response to these changes. Patients were followed up to one-year post-surgery using our institution's EVOLVE system. The main outcome measure in this study was new post-operative neurological signs and/or symptoms and what effect, if any, IONM and subsequent surgeon intervention had on these complications.

Result

Indications for SCM included cervical stenosis, cervical disc prolapse, unstable fractures and bony metastases. Signal changes were observed in 33% (n=55) of cases. 24 of these patients responded to re-positioning. There were 7 total complications with full resolution by 12 months. False negative rate was 2.4% (n=4). There was one true positive. The largest cohort of patients included those who experienced no signal changes and subsequently no post-operative deficits (n=124).

Conclusion

SCM is a non-invasive clinical tool that may be utilised for medicolegal reasons. Its use as a clinical tool is questionable given its relatively high false negative rate and low false positive rate.

Take-home message

Spinal cord monitoring may be used by spinal surgeons for medicolegal reasons if desired. Its use as a clinical tool is questionable at best.

Open and Endovascular Management of Acute Mesenteric Ischaemia: A Systematic Review

BACKGROUND

Acute mesenteric ischaemia (AMI) is a life-threatening surgical emergency resulting from thromboembolic occlusion of the mesenteric vasculature. Traditional management of AMI has been open revascularisation with or without bowel resection-a procedure which carries considerable morbidity and mortality in an already unwell, compromised patient. Endovascular and more minimally invasive management approaches to AMI have been reported. Proponents of endovascular management suggest this approach may be associated with reduced morbidity and mortality compared with open surgery.

OBJECTIVES

To assess the impact of endovascular approach for AMI on mortality and need for subsequent laparotomy and/or bowel resection.

DATA SOURCES

The search bodies PubMed and Medline were interrogated.

ELIGIBILITY CRITERIA, PARTICIPANTS AND INTERVENTIONS

All studies in English with greater than 10 patients examining outcomes for patients undergoing endovascular intervention for acute mesenteric ischaemia were included. All patients over 18 years presenting with a diagnosis of acute mesenteric ischaemia secondary to an arterial thromboembolic source were included. Studies examining endovascular intervention alone or endovascular and open intervention were selected.

RESULTS

The 30-day mortality for endovascular approach from all 13 studies was 16-42%. Of the 7 comparative studies including results of open revascularisation, the 30-day mortality for patient treated with an endovascular approach was 15-39% versus 33-50% for open revascularisation. Laparotomy rates post-initial endovascular intervention ranged from 13 to 73%. Bowel resection post-endovascular therapy ranged from 14 to 40% among studies. Concerning 7 comparative studies for open versus endovascular revascularisation, the rate of bowel resection in the endovascular group ranged 14-28% and 33-63% in the open cohort. Endovascular intervention also demonstrated lower median length (s) of bowel resected.

LIMITATIONS

Heterogeneity of studies and patient populations studied including selection bias.

CONCLUSIONS AND IMPLICATIONS OF FINDINGS

Endovascular management may be associated with reduced mortality and need for/length of bowel resection compared with the traditional open approach, but there remains a paucity of robust data to support this. The available literature illustrates that a subgroup of patients without haemodynamic compromise and more insidious onset may garner benefit from endovascular intervention.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

A single-blind, randomised controlled trial on the effects of lithium and quetiapine monotherapy on the trajectory of cognitive functioning in first episode mania: A 12-month follow-up study

Background

Cognitive deficits have been reported during the early stages of bipolar disorder; however, the role of medication on such deficits remains unclear. The aim of this study was to compare the effects of lithium and quetiapine monotherapy on cognitive performance in people following first episode mania.

Methods

The design was a single-blind, randomised controlled trial on a cohort of 61 participants following first episode mania. Participants received either lithium or quetiapine monotherapy as maintenance treatment over a 12-month follow-up period. The groups were compared on performance outcomes using an extensive cognitive assessment battery conducted at baseline, month 3 and month 12 follow-up time-points.

Results

There was a significant interaction between group and time in phonemic fluency at the 3-month and 12-month endpoints, reflecting greater improvements in performance in lithium-treated participants relative to quetiapine-treated participants. After controlling for multiple comparisons, there were no other significant interactions between group and time for other measures of cognition.

Conclusion

Although the effects of lithium and quetiapine treatment were similar for most cognitive domains, the findings imply that early initiation of lithium treatment may benefit the trajectory of cognition, specifically verbal fluency in young people with bipolar disorder. Given that cognition is a major symptomatic domain of bipolar disorder and has substantive effects on general functioning, the ability to influence the trajectory of cognitive change is of considerable clinical importance.

Clinicopathological features and oncological outcomes of patients with young-onset rectal cancer

BACKGROUND

The incidence of rectal cancer among adults aged less than 50 years is rising. Survival data are limited and conflicting, and the oncological benefit of standard neoadjuvant and adjuvant therapies is unclear.

METHODS

Disease-specific outcomes of patients diagnosed with rectal cancer undergoing surgical resection with curative intent between 2006 and 2016 were analysed.

RESULTS

A total of 797 patients with rectal cancer were identified, of whom 685 had surgery with curative intent. Seventy patients were younger than 50 years and 615 were aged 50 years or more. Clinical stage did not differ between the two age groups. Patients aged less than 50 years were more likely to have microsatellite instability (9 versus 1·6 per cent; P = 0·003) and Lynch syndrome (7 versus 0 per cent; P < 0·001). Younger patients were also more likely to receive neoadjuvant chemoradiotherapy (67 versus 53·3 per cent; P = 0·003) and adjuvant chemotherapy (41 versus 24·2 per cent; P = 0·006). Five-year overall survival was better in those under 50 years old (80 versus 72 per cent; P = 0·013). The 5-year disease-free survival rate was 81 per cent in both age groups (P = 0·711). There were no significant differences in the development of locoregional recurrence or distant metastases.

CONCLUSION

Despite accessing more treatment, young patients have disease-specific outcomes comparable to those of their older counterparts.

Signal processing methods for reducing artifacts in microelectrode brain recordings caused by functional electrical stimulation

OBJECTIVE

Functional electrical stimulation (FES) is a promising technology for restoring movement to paralyzed limbs. Intracortical brain-computer interfaces (iBCIs) have enabled intuitive control over virtual and robotic movements, and more recently over upper extremity FES neuroprostheses. However, electrical stimulation of muscles creates artifacts in intracortical microelectrode recordings that could degrade iBCI performance. Here, we investigate methods for reducing the cortically recorded artifacts that result from peripheral electrical stimulation.

APPROACH

One participant in the BrainGate2 pilot clinical trial had two intracortical microelectrode arrays placed in the motor cortex, and thirty-six stimulating intramuscular electrodes placed in the muscles of the contralateral limb. We characterized intracortically recorded electrical artifacts during both intramuscular and surface stimulation. We compared the performance of three artifact reduction methods: blanking, common average reference (CAR) and linear regression reference (LRR), which creates channel-specific reference signals, composed of weighted sums of other channels.

MAIN RESULTS

Electrical artifacts resulting from surface stimulation were 175  ×  larger than baseline neural recordings (which were 110 µV peak-to-peak), while intramuscular stimulation artifacts were only 4  ×  larger. The artifact waveforms were highly consistent across electrodes within each array. Application of LRR reduced artifact magnitudes to less than 10 µV and largely preserved the original neural feature values used for decoding. Unmitigated stimulation artifacts decreased iBCI decoding performance, but performance was almost completely recovered using LRR, which outperformed CAR and blanking and extracted useful neural information during stimulation artifact periods.

SIGNIFICANCE

The LRR method was effective at reducing electrical artifacts resulting from both intramuscular and surface FES, and almost completely restored iBCI decoding performance (>90% recovery for surface stimulation and full recovery for intramuscular stimulation). The results demonstrate that FES-induced artifacts can be easily mitigated in FES  +  iBCI systems by using LRR for artifact reduction, and suggest that the LRR method may also be useful in other noise reduction applications.

Review of external referrals to a regional stroke centre: it is not just about thrombectomy

AIMS

To determine the experience of a regional stroke referral centre of external referrals for endovascular thrombectomy (EVT) in patients with symptoms of acute ischaemic stroke (AIS) and large vessel occlusion (LVO).

MATERIALS AND METHODS

Data were collected prospectively over two 4-month periods (2017-2018) on consecutive external referrals for EVT. Baseline demographics, imaging findings, and key time parameters were recorded. Reasons for not transferring patients and for not performing EVT were recorded. Key time intervals were calculated and compared between the transferred and non-transferred group with and without intracranial occlusion and between the transferred patients who underwent thrombectomy and those who did not.

RESULTS

Two hundred and sixty-two patients were referred. Sixty-one percent (n=159) were accepted and transferred for treatment. Of those transferred, 86% (n=136) had EVT. Fourteen percent (n=23) were unsuitable for EVT on arrival due to no vessel occlusion (48% n=11), poor Alberta Stroke Program Early CT Score (ASPECTS)/established infarct (30%, n=7) haemorrhage (9%, n=2), and clinical recovery (13% n=3). One hundred and three patients (39%) were ineligible for EVT following phone discussion due to absence of intracranial occlusion (59%, n=61), low ASPECTS (22%, n=23), distal occlusion (4%, n=4), low/improving National Institutes of Health Stroke Scale (NIHSS; 10.7%, n=11), and poor modified Rankin Scale (mRS) at baseline (3%, n=3). Patients with LVO but not transferred had longer onset to hospital arrival time compared with those transferred 151.5 versus 91 minutes (p<0.005), with a trend also toward a longer door to CT/CTA 40 minutes versus 30 minutes (p=0.142).

CONCLUSION

These data provide valuable insights into the service provision of a comprehensive stroke network. The present rates of EVT and futile transfers are modest compared to published data. Access to neuroradiology and specialised stroke assessment is crucial to optimise time to treatment.

Small Bowel Gastrointestinal Bleeding Diagnosis and Management-A Narrative Review

Background: Small bowel bleeding accounts for 5-10% of all gastrointestinal bleeding. Despite advances in imaging, endoscopy and minimally invasive therapeutic techniques, its diagnosis and treatment remains a challenge and a standardized algorithm for approaching suspected small bowel bleeding remains elusive. Furthermore, the choice of investigation is subject to timing of presentation and accessibility to investigations. The aim of this study was to construct a narrative review of recent literature surrounding the diagnosis and management of small bowel bleeding. Methods: A literature review was conducted examining the database pubmed with the following key words and Boolean operators: occult GI bleed OR mesenteric bleed OR gastrointestinal hemorrhage OR GI hemorrhage AND management. Articles were selected and reviewed based on relevance to the research topic. Where necessary, the full text was sought to further assess relevance. Results: In overt GI bleeding, CT angiography and red cell scintigraphy are both feasible and reliable diagnostic imaging modalities if standard endoscopy is negative. Red cell scintigraphy may be advantageous through detection of lower bleeding rates but it is subject to availability. Overt bleeding and a positive CT angiogram or red cell scan improves the diagnostic yield of formal angiography ± embolization. Video capsule endoscopy or double balloon endoscopy can be considered in occult GI bleeding following normal upper and lower endoscopy. Conclusions: Small bowel bleeding remains a rare but significant diagnostic and therapeutic challenge. Technological advances in diagnostics have aided evaluation but have not broadened the range of therapeutic interventions.

Abstract P1-09-13: A real world evidence study of BRCA mutations and survival in HER2-negative breast cancer

Background: Limited data exist on the natural history (treated with standard of care) of metastatic breast cancer (mBC) characterized by germline breast cancer susceptibility gene mutations (gBRCAm). Real-world data examining survival for patients with gBRCAm mBC, overall and separated into gBRCA1m and gBRCA2m, compared to gBRCA wild type (wt) mBC, can help to clarify the prognostic outlook associated with the gBRCA mutation.

Methods: Adults with human epidermal growth factor receptor 2 negative (HER2-) mBC diagnosed from January 2013 – August 2017 were retrospectively selected from the Flatiron Health Oncology electronic medical record database. Patients were classified as having gBRCA1m, gBRCA2m, or gBRCAwt disease. Those who did not receive the genetic testing or who had equivocal results were classified as gBRCA unknown. Overall survival (OS) was calculated from first diagnosis of mBC, as well as from the start of first- and second-line therapy for metastatic disease. Lines of therapy included both hormonal and systemic therapies. Kaplan-Meier analyses provided median OS with 95% confidence interval (CI). Unadjusted log-rank tests compared OS between gBRCA1m and gBRCA2m, and between overall gBRCAm and gBRCAwt.

Results: Of 8,080 patients selected, mean age at first mBC diagnosis was 64 years, 98.7% were female, and 82.0% had evidence of hormone receptor positive disease. gBRCA status was known for 1,852 (22.9%) of patients, of whom 89 (4.8%) had gBRCA1m, 152 (8.2%) had gBRCA2m, and 8 (0.4%) had both gBRCA mutations. Patients with known gBRCA status were younger, with mean ages of 52 years for gBRCAm, 55 years for gBRCAwt, and 67 years for gBRCA unknown. Hormone receptor positive disease was less common among those with known gBRCA status (71.9%, 77.2%, and 83.6% for gBRCAm, gBRCAwt, and gBRCA unknown, respectively). Median (95% CI) OS from mBC diagnosis was 22 (14 - 26) months for gBRCA1m and 30 (27 - 37) months for gBRCA2m (p = 0.01), though numbers were quite small by the median timepoint. Overall gBRCAm disease was associated with median survival of 28 (25 - 32) months, compared to 32 (30 - 35) months for gBRCAwt (p = 0.07); survival was similar between groups for the first 24 months but declined thereafter in the gBRCAm group. Similar patterns were observed for OS after the start of first- and second-line therapy, although no comparisons were significant. Further analyses will present adjusted results and comparisons with outcomes for the patients with gBRCA unknown.

Conclusions: This real-world study of patients receiving care in largely community oncology clinics suggests that survival after diagnosis of mBC is reduced in patients with gBRCA1m compared to gBRCA2m disease and may be reduced in gBRCAm mBC overall. Effective treatments targeted for the gBRCAm subtypes of mBC appear to be needed.

Citation Format: Dalvi T, McLaurin K, Briceno J, Nordstrom B, Bennett J, Hettle R, Murphy B, Collins J, McCutcheon S. A real world evidence study of BRCA mutations and survival in HER2-negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-09-13.

Closed-loop cortical control of virtual reach and posture using Cartesian and joint velocity commands

OBJECTIVE

Brain-computer interfaces (BCIs) are a promising technology for the restoration of function to people with paralysis, especially for controlling coordinated reaching. Typical BCI studies decode Cartesian endpoint velocities as commands, but human arm movements might be better controlled in a joint-based coordinate frame, which may match underlying movement encoding in the motor cortex. A better understanding of BCI controlled reaching by people with paralysis may lead to performance improvements in brain-controlled assistive devices.

APPROACH

Two intracortical BCI participants in the BrainGate2 pilot clinical trial performed a visual 3D endpoint virtual reality reaching task using two decoders: Cartesian and joint velocity. Task performance metrics (i.e. success rate and path efficiency) and single feature and population tuning were compared across the two decoder conditions. The participants also demonstrated the first BCI control of a fourth dimension of reaching, the arm's swivel angle, in a 4D posture matching task.

MAIN RESULTS

Both users achieved significantly higher success rates using Cartesian velocity control, and joint controlled trajectories were more variable and significantly more curved. Neural tuning analyses showed that most single feature activity was best described by a Cartesian kinematic encoding model, and population analyses revealed only slight differences in aggregate activity between the decoder conditions. Simulations of a BCI user reproduced trajectory features seen during closed-loop joint control when assuming only Cartesian-tuned features passed through a joint decoder. With minimal training, both participants controlled the virtual arm's swivel angle to complete a 4D posture matching task, and achieved significantly higher success using a Cartesian  +  swivel velocity decoder compared to a joint velocity decoder.

SIGNIFICANCE

These results suggest that Cartesian velocity command interfaces may provide better BCI control of arm movements than other kinematic variables, even in 4D posture tasks with swivel angle targets.

Youngest survivor of perinatal infection by Eikenella corrodens : case analysis and literature review highlighting the merits of placental swab culture

Eikenella corrodens has been noted as a causative organism in both neonatal and perinatal sepsis. Positivity of blood cultures at birth among preterm infants may be influenced by the maternal use of peripartum antimicrobials and a normal C-reactive protein result within the first 24 hours need not always reflect the absence of fetal invasion by the highly pathogenic organisms. For these reasons, supportive and adjunctive approaches such as appropriately collected placental swabs for culture would be of value in optimizing the antimicrobial choice for sick preterm infants during the early neonatal period. Fetal infection by E. corrodens detected by placental swab culture influencing antimicrobial management of an extremely premature infant with sepsis is described. Management of the youngest premature survivor with the lowest birthweight among the reported cases in English language of neonatal E. corrodens infection is summarized and literature is reviewed. The value of placental swab, which is often underused, is highlighted in this review.

A Study To Assess The Prevalence Of Exercise-Induced Bronchoconstriction In Inter-County Hurling

Exercise-Induced Bronchoconstriction (EIB) is an acute, transient airway narrowing occurring after exercise which may impact athletic performance. Studies report 10% of the general population and up to 90% of asthmatics experience EIB. Ninety-two players from three elite hurling squads underwent a spirometric field-based provocation test with real-time heart rate monitoring and lactate measurements to ensure adequate exertion. Players with a new diagnosis of EIB and those with a negative field-test but with a previous label of EIB or asthma underwent further reversibility testing and if negative, methacholine challenge. Eight (8.7%) of players had EIB, with one further athlete having asthma with a negative field test. Interestingly, only three out of 12 players who had previously been physician-labelled with EIB or asthma had their diagnosis objectively confirmed. Our study highlights the role of objective testing in EIB.

A randomised clinical study to determine the effect of a toothpaste containing enzymes and proteins on plaque oral microbiome ecology

The numerous species that make up the oral microbiome are now understood to play a key role in establishment and maintenance of oral health. The ability to taxonomically identify community members at the species level is important to elucidating its diversity and association to health and disease. We report the overall ecological effects of using a toothpaste containing enzymes and proteins compared to a control toothpaste on the plaque microbiome. The results reported here demonstrate that a toothpaste containing enzymes and proteins can augment natural salivary defences to promote an overall community shift resulting in an increase in bacteria associated with gum health and a concomitant decrease in those associated with periodontal disease. Statistical analysis shows significant increases in 12 taxa associated with gum health including Neisseria spp. and a significant decrease in 10 taxa associated with periodontal disease including Treponema spp. The results demonstrate that a toothpaste containing enzymes and proteins can significantly shift the ecology of the oral microbiome (at species level) resulting in a community with a stronger association to health.

Clinical and Histopathologic Characterization of Canine Chronic Ulcerative Stomatitis

Canine chronic ulcerative stomatitis, also known as chronic ulcerative paradental stomatitis, is a painful condition of the oral cavity. The purpose of this study was to determine if there are commonalities in clinical and radiographic features among patients, whether the histopathologic evaluation might inform the pathogenesis, and whether the condition appears similar to human oral mucosal diseases. To do this, we prospectively collected clinical, radiographic, and histopathologic data from 20 dogs diagnosed with the disease. Clinical data were based on a clinical disease activity index, oral and periodontal examination parameters, and full-mouth dental radiographs. The histopathological and immunohistochemical data were based on oral mucosal samples obtained from erosive or ulcerated areas. Our findings revealed that canine chronic stomatitis is clinically characterized by painful oral mucosal ulcers of varying size, pattern, appearance, and distribution, most often associated with teeth with early periodontitis. Histologic examination revealed a subepithelial lichenoid band (interface mucositis) where B cells, T cells, and Forkhead-box protein 3 (FoxP3)- and interleukin-17-expressing cells were present. These cells might play a role in the underlying immune response and an immune-mediated pathogenesis is suspected. The clinical and histopathologic features of this chronic inflammatory mucosal disease in dogs resemble those of oral lichen planus in humans.

Cutaneous Ossifying Fibroma in a Neon Tetra (Paracheirodon innesi)

A cutaneous proliferative mass was identified arising from the caudal peduncle of a captive neon tetra fish (Paracheirodon innesi). The lesion was histologically consistent with an ossifying fibroma (OF), a fibro-osseous proliferative lesion typically identified in the jaws or tooth-associated supportive tissues of mammals. Although it has been previously reported, there is no recent report of this lesion occurring in a fish. This is the first report of a cutaneous ossifying fibroma in a characin fish. The authors speculate on the pathogenesis of this lesion, which may have arisen from the scale-associated mesenchymal tissues.

Surgical Pulmonary Embolectomy: Experience in a Series of 37 Consecutive Cases

BACKGROUND

Massive pulmonary embolism is a poorly tolerated condition. Treatment options in this condition include anticoagulation and primary reperfusion therapy - systemic thrombolysis, catheter based treatments or surgical embolectomy. There is little data on the relative efficacy of each treatment.

METHODS

The preoperative characteristics and outcomes of patients referred for surgical embolectomy between 2000-2014 was reviewed. Echocardiography was performed in the majority of patients before and after surgery.

RESULTS

Thirty-seven patients underwent pulmonary embolectomy between 2000-2014. One patient died within 30 days, another before leaving hospital. All other patients were alive at the time of follow-up (survival 94.6% at median 36 months). Median ventilation time was 24hours. Median hospital length of stay was 10.5 days. There was echocardiographic evidence of severe right ventricular strain (increased size and decreased function) before surgery, which was significantly improved to within the normal range by discharge, and follow-up.

CONCLUSIONS

Surgical embolectomy is a safe procedure, with low mortality, improved postoperative right ventricular function and pulmonary pressure, and good long-term outcome. Early relief of a large proportion of the clot burden can be life-saving. There should be consideration for its use as an initial treatment strategy in patients with massive or submassive pulmonary embolus with a large burden of proximal clot. A multidisciplinary approach for the treatment of these patients is required.

Clinical and Pathological Features of Pheochromocytoma in the Horse: A Multi-Center Retrospective Study of 37 Cases (2007-2014)

Background

Pheochromocytoma is the most common adrenal medullary neoplasm of domestic animals, but it is rare in horses. Antemortem diagnosis in horses is difficult, with clinical signs often being vague or non‐specific.

Objective

The objective of this study was to describe the clinical, laboratory, and pathologic findings of pheochromocytoma in horses.

Animals

Thirty‐seven horses diagnosed with pheochromocytoma based on postmortem examination from 2007 to 2014.

Methods

Retrospective case series.

Results

Pheochromocytoma was identified in 37/4094 horses during postmortem examination. Clinical signs consistent with pheochromocytoma had been observed antemortem in only 7 cases, with the remainder being incidental findings. Colic was the most common presenting complaint (13 of 37 cases) and tachycardia was noted in 95% of cases (median heart rate of 86 bpm in clinical cases). Hyperlactatemia (median, 4.9 mmol/L) and hyperglycemia (median, 184 mg/dL) were the most common clinicopathologic abnormalities. Hemoperitoneum caused by rupture of pheochromocytoma was noted in 4/7 clinical cases. Concurrent endocrine abnormalities (eg, thyroid adenoma, adrenal hyperplasia, pituitary pars intermedia hyperplasia or adenoma, parathyroid C‐cell carcinoma) were found in 27/37 horses, with 8/37 horses having lesions consistent with multiple endocrine neoplasia syndrome as described in humans.

Conclusions

Pheochromocytoma was diagnosed in 0.95% of horses presented for necropsy. The majority of these were incidental findings, but pheochromocytoma was thought to contribute to clinical findings in 19% of cases, and multiple endocrine neoplasms were commonly seen. Usually an incidental finding at necropsy, pheochromocytoma may cause acute death from intraperitoneal exsanguination and should be considered in horses presenting with colic, tachycardia, and hemoperitoneum.