Negative Pressure Wound Therapy to Reduce Surgical Site Infections after CRS/HIPEC.

BACKGROUND: Surgical site infections (SSIs) are a common cause of morbidity after cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) for peritoneal malignancy. Negative pressure wound therapy (NPWT) has been proposed as a method to reduce the rates of SSIs; however, there is paucity in the literature on the efficacy in this population. The goal of this study was to determine whether routine use of NPWT in patients undergoing CRS/HIPEC could reduce the risk of developing SSI. METHODS: We performed a retrospective before-after study to assess the rates of SSI with NPWT compared with a standard postoperative surgical dressing (SSD) in all patients undergoing CRS/HIPEC from November 2013 to December 2021 at a single tertiary care center. The primary outcome was rate of SSI. A multivariate logistic regression analysis was performed to evaluate for risk factors for SSI. RESULTS: A total of 178 patients were treated with CRS/HIPEC over the study period. Seventy patients had placement of SSD, and 108 patients had placement of NPWT. Rates of SSI were 11.4% (8/70) and 5.6% (6/108) in the two groups, respectively (p = 0.16). On multivariate analysis, patients treated with NPWT had a significantly lower risk of developing an SSI (OR 0.24 [0.06, 0.92], p = 0.037). Patients living >50 km from the hospital had significantly higher risk of developing SSI (OR 2.03 [1.09, 3.78], p = 0.026). CONCLUSIONS: These results suggest that routine use of NPWT can reduce the risk of developing an SSI in patients undergoing CRS/HIPEC for peritoneal malignancy.

Repeated microdoses of LSD do not alter anxiety or boldness in zebrafish.

The therapeutic use of lysergic acid diethylamide (LSD) has resurfaced in the last decade, prompting further scientific investigation into its effectiveness in many animal models. Zebrafish (Danio rerio) are a popular model organism in medical sciences and are used to examine the repeated administration of pharmacological compounds. Previous zebrafish research found acute LSD altered behaviour and cortisol levels at high (250 µg/L) but not low (5-100 µg/L) levels. In this study, we used a motion tracking system to record and analyze the movement patterns of zebrafish after acute and repeated 10-day LSD exposure (1.5 µg/L, 15 µg/L, 150 µg/L) and after seven days of withdrawal. The open-field and novel object approach tests were used to examine anxiety-like behaviour, boldness, and locomotion. In the acute experiments we observed a significant decrease in high mobility with 1.5 µg/L, 15 µg/L, and 150 µg/L of LSD compared to the control and a decrease in velocity with 1.5 and 15 µg/L. In repeated experiments, there were no significant differences in the levels of anxiety, boldness, or locomotion between all LSD groups and controls immediately after 10-day treatment or after withdrawal.

ß-Carboline (FG-7142) modulates fear but not anxiety-like behaviour in zebrafish.

The ß-Carboline FG-7142 is a partial inverse agonist at the benzodiazepine allosteric site on the GABA-A receptor that induces anxiogenic, proconvulsant, and appetite-reducing effects in many species, including humans. Seizure-kindling effects have been well studied, however anxiogenic properties are relatively unexplored. This study aimed to investigate concentration-dependent effects of FG-7142 on anxiety-like behaviour and fear responses in zebrafish (Danio rerio) using the open-field test (OF) and novel object approach test (NOA). A U-shaped distribution was found with maximal responses in increased immobility and reduced distance moved at 10 µM in the NOA but not the OF. Follow up experiments demonstrated a lack of effect in repeated OF testing and no changes in opercular movements. Furthermore, the effect of FG-7142 was reversed with ethanol treatment. These results suggest that FG-7142 elicits a 'freezing' response in zebrafish via the introduction of novelty, suggesting fear-induction. These findings indicate that FG-7142 may act as an agent to promote acute fear responses in zebrafish.

Survival of Patients With Head and Neck Merkel Cell Cancer: Findings From the Pan-Canadian Merkel Cell Cancer Collaborative.

Importance: Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine carcinoma. Due to its relatively low incidence and limited prospective trials, current recommendations are guided by historical single-institution retrospective studies. Objective: To evaluate the overall survival (OS) of patients in Canada with head and neck MCC (HNMCC) according to American Joint Committee on Cancer 8th edition staging and treatment modalities. Design, Setting, and Participants: A retrospective cohort study of 400 patients with a diagnosis of HNMCC between July 1, 2000, and June 31, 2018, was conducted using the Pan-Canadian Merkel Cell Cancer Collaborative, a multicenter national registry of patients with MCC. Statistical analyses were performed from January to December 2022. Main Outcomes and Measures: The primary outcome was 5-year OS. Multivariable analysis using a Cox proportional hazards regression model was performed to identify factors associated with survival. Results: Between 2000 and 2018, 400 patients (234 men [58.5%]; mean [SD] age at diagnosis, 78.4 [10.5] years) with malignant neoplasms found in the face, scalp, neck, ear, eyelid, or lip received a diagnosis of HNMCC. At diagnosis, 188 patients (47.0%) had stage I disease. The most common treatment overall was surgery followed by radiotherapy (161 [40.3%]), although radiotherapy alone was most common for stage IV disease (15 of 23 [52.2%]). Five-year OS was 49.8% (95% CI, 40.7%-58.2%), 39.8% (95% CI, 26.2%-53.1%), 36.2% (95% CI, 25.2%-47.4%), and 18.5% (95% CI, 3.9%-41.5%) for stage I, II, III, and IV disease, respectively, and was highest among patients treated with surgery and radiotherapy (49.9% [95% CI, 39.9%-59.1%]). On multivariable analysis, patients treated with surgery and radiotherapy had greater OS compared with those treated with surgery alone (hazard ratio [HR], 0.76 [95% CI, 0.46-1.25]); however, this was not statistically significant. In comparison, patients who received no treatment had significantly worse OS (HR, 1.93 [95% CI, 1.26-2.96)]. Conclusions and Relevance: In this cohort study of the largest Canada-wide evaluation of HNMCC survival outcomes, stage and treatment modality were associated with survival. Multimodal treatment was associated with greater OS across all disease stages.

Cannabinoid type-2 receptors modulate terpene induced anxiety-reduction in zebrafish.

Terpenes are the most extensive and varied group of naturally occurring compounds mostly found in plants, including cannabis, and have an array of potential therapeutic benefits for pathological conditions. The endocannabinoid system can potently modulate anxiety in humans, rodents, and zebrafish. The 'entourage effect' suggests terpenes may target cannabinoid CB1 and CB2 receptors, among others, but this requires further investigation. In this study we first tested for anxiety-altering effects of the predominant 'Super-Class' terpenes, bisabolol (0.001%, 0.0015%, and 0.002%) and terpinolene (TPL; 0.01%, 0.05%, and 0.1%), in zebrafish with the open field test. Bisabolol did not have an effect on zebrafish behaviour or locomotion. However, TPL caused a significant increase in time spent in the inner zone and decrease in time spent in the outer zone of the arena indicating an anxiolytic (anxiety decreasing) effect. Next, we assessed whether CB1 and CB2 receptor antagonists, rimonabant and AM630 (6-Iodopravadoline) respectively, could eliminate or reduce the anxiolytic effects of TPL (0.1%) and ß-caryophyllene (BCP; 4%), another super-class terpene previously shown to be anxiolytic in zebrafish. Rimonabant and AM630 were administered prior to terpene exposure and compared to controls and fish exposed to only the terpenes. AM630, but not rimonabant, eliminated the anxiolytic effects of both BCP and TPL. AM630 modulated locomotion on its own, which was potentiated by terpenes. These findings suggest the behavioural effects of TPL and BCP on zebrafish anxiety-like behaviour are mediated by a selective preference for CB2 receptor sites. Furthermore, the CB2 pathways mediating the anxiolytic response are likely different from those altering locomotion.

Innate colour preference in zebrafish (Danio rerio).

Innate (natural) colour preference in animals is used for a variety of behavioural neuroscience purposes in many animal models. In zebrafish, colour preference is often used in combination with place preference testing and some memory tests. However, baseline colour preference seems to differ in the few studies examining this innate behaviour. This necessitates a protocol for reliable colour preference testing to establish preferences prior to using more complex behavioural paradigms. This procedure involves an aquatic plus maze with a central neutral zone and 4 coloured zones: red, green, yellow, blue. Adult zebrafish spent significantly more time in the blue zone compared to the red and yellow zones. There were no sex differences in colour preference. This procedure is a rapid, affordable, straightforward, and effective method to establish baseline colour preference.

Cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC) for peritoneal mesothelioma: Canadian practices and outcomes.

INTRODUCTION: Peritoneal mesothelioma (PM) is a rare malignancy originating from the peritoneal lining. Cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC) is the standard-of-care for patients with isolated PM. Due to a paucity of prospective data there are several different HIPEC protocols. The aims of this study are to describe the CRS and HIPEC protocols for PM and patient outcomes across Canada. METHODS: A multicenter retrospective study was performed on patients diagnosed and treated for PM with CRS and HIPEC in four major peritoneal disease centers in Canada between 2000 and 2021. Data on patient characteristics, treatment patterns, postoperative morbidity, recurrence, and survival were collected. RESULTS: A total of 72 patients were identified. Mean age was 52 years (17-75) and 37.5% were male. Epithelioid (70.1%) and multicystic (13%) mesothelioma were the most common subtypes. Twenty-one patients (30%) were treated with neoadjuvant chemotherapy. CRS and HIPEC was performed in 64 patients (91.4%). Of these, the mean PCI was 22 (2-39) and cisplatin+doxorubicin was the most common HIPEC regimen (n = 33, 51.6%). A semi-closed coliseum technique was used in 68.8% of HIPECs and the mean duration of surgery was 486 min (90-1052). Clavien-Dindo III or IV complications occurred in 12 patients (16.9%). With a median follow-up of 24 months (0.2-104.4), we found a 5-year overall survival of 61% and a 5-year recurrence-free survival of 35%. CONCLUSION: CRS and HIPEC is a safe and effective treatment modality for well-selected patients with PM, with some achieving prolonged survival.

Mesothelioma In Situ Mimicking Well-differentiated Papillary Mesothelial Tumor.

We have previously hypothesized that well-differentiated papillary mesothelial tumor (WDPMT) consists of 2 morphologically identical lesions, one of which is true WDPMT, while the other is a form of mesothelioma in situ. Here, we report 8 examples of the latter phenomenon, 3 with pleural disease (2 men/1 woman, ages 66 to 78 y); and 5 with peritoneal disease (all women, ages 31 to 81 y). At presentation the pleural cases all had effusions but no evidence of pleural tumor on imaging. Four of the 5 peritoneal cases had ascites as the initial finding and all 4 had nodular lesions that by imaging and/or direct inspection were thought to represent a diffuse peritoneal malignancy. The fifth peritoneal case presented with an umbilical mass. Microscopically, the pleural and peritoneal lesions looked like diffuse WDPMT, but all had lost BAP1. Occasional microscopic foci of superficial invasion were present in 3/3 pleural cases, while single nodules of invasive mesothelioma and/or occasional foci of superficial microscopic invasion were found in all of the peritoneal cases. The pleural tumor patients developed what clinically appeared to be invasive mesothelioma at 45, 69, and 94 months. Four/five peritoneal tumor patients underwent cytoreductive surgery and heated intraperitoneal chemotherapy. Three with follow-up data are alive without recurrence at 6, 24, and 36 months; 1 patient refused treatment but is alive at 24 months. We conclude that mesothelioma in situ morphologically mimicking WDPMT is strongly associated with the synchronous or metachronous development of invasive mesothelioma, but that these lesions appear to progress very slowly.

Examining behavioural test sensitivity and locomotor proxies of anxiety-like behaviour in zebrafish.

This study assessed the sensitivity of four anxiety-like behaviour paradigms in zebrafish: the novel tank dive test, shoaling test, light/dark test, and the less common shoal with novel object test. A second goal was to measure the extent to which the main effect measures are related to locomotor behaviours to determine whether swimming velocity and freezing (immobility) are indicative of anxiety-like behaviour. Using the well-established anxiolytic, chlordiazepoxide, we found the novel tank dive to be most sensitive followed by the shoaling test. The light/dark test and shoaling plus novel object test were the least sensitive. A principal component analysis and a correlational analysis also showed the locomotor variables, velocity and immobility, did not predict the anxiety-like behaviours across all behaviour tests.

Factors associated with recurrent appendicitis after nonoperative management.

BACKGROUND: The objective of this study is to identify predictors for recurrent appendicitis in patients with appendicitis previously treated nonoperatively. METHODS: This is a prospective cohort study of all adult patients with appendicitis treated at a tertiary care hospital. Patient demographics, radiographic information, management, and clinical outcomes were recorded. The primary outcome was recurrent appendicitis within 6 months after discharge from the index admission. Given the competing risk of interval appendectomy, a time-to-event competing-risk analysis was performed. RESULTS: Of the 699 patients presenting with appendicitis, 74 were treated nonoperatively (35 [47%] were women; median [IQR] age, 48 [33,64] years), and 21 patients (29%) had recurrent appendicitis. On univariate and multivariate analysis, presence of an appendicolith on imaging was the only factor associated with a higher risk of recurrent appendicitis (p = 0.02). CONCLUSIONS: The presence of appendicolith was associated with an increased risk of developing recurrent appendicitis within 6 months.

Effects of ocean acidification on dopamine-mediated behavioral responses of a coral reef damselfish.

We investigated whether CO2-induced ocean acidification (OA) affects dopamine receptor-dependent behavior in bicolor damselfish (Stegastes partitus). Damselfish were kept in aquaria receiving flow through control (pH ~ 8.03; pCO2 ~ 384 µatm) or OA (pH ~ 7.64; CO2 ~ 1100 µatm) seawater at a rate of 1 L min-1. Despite this relatively fast flow rate, fish respiration further acidified the seawater in both control (pH ~7.88; pCO2 ~ 595 µatm) and OA (pH ~7.55; pCO2 ~ 1450 µatm) fish-holding aquaria. After five days of exposure, damselfish locomotion, boldness, anxiety, and aggression were assessed using a battery of behavioral tests using automated video analysis. Two days later, these tests were repeated following application of the dopamine D1 receptor agonist SKF 38393. OA-exposure induced ceiling anxiety levels that were significantly higher than in control damselfish, and SKF 38393 increased anxiety in control damselfish to a level not significantly different than that of OA-exposed damselfish. Additionally, SKF 38393 decreased locomotion and increased boldness in control damselfish but had no effect in OA-exposed damselfish, suggesting an alteration in activity of dopaminergic pathways that regulate behavior under OA conditions. These results indicate that changes in dopamine D1 receptor function affects fish behavior during exposure to OA. However, subsequent measurements of seawater sampled using syringes during the daytime (~3-4 pm local time) from crevasses in coral reef colonies, which are used as shelter by damselfish, revealed an average pH of 7.73 ± 0.03 and pCO2 of 925.8 ± 62.2 µatm; levels which are comparable to Representative Concentration Pathway (RCP) 8.5 predicted end-of-century mean OA levels in the open ocean. Further studies considering the immediate environmental conditions experienced by fish as well as individual variability and effect size are required to understand potential implications of the observed OA-induced behavioral effects on damselfish fitness in the wild.

Zebrafish (Danio rerio) shoaling in light and dark conditions involves a complex interplay between vision and lateral line.

We know little about how - or even if in some species - fish shoal in darkness. We hypothesized that 'dark shoaling' occurs in zebrafish and therefore must depend upon lateral line sensory input. Shoaling in groups of five adult zebrafish was analyzed with motion tracking software. We measured average inter-individual distance, time near the arena wall (thigmotaxis zone) and total distance traveled under normal room light, and in near-complete darkness (infrared light at 850 nm). These observations were repeated in fish treated with cobalt chloride (CoCl2), which ablates lateral line function. In untreated controls, dark shoaling was reduced compared to in light, but nonetheless still present. Elimination of lateral line sensory input by CoCl2 treatment similarly reduced, but did not eliminate, shoaling under both light and dark. Our findings indicate that normal zebrafish shoaling in light or dark requires both visual and lateral line inputs, with neither alone sufficient for normal shoaling.

Risk of lymph node metastasis in early gastric cancer for a Western population.

INTRODUCTION: Endoscopic resection (ER) of early gastric cancer (EGC) is increasingly used in Eastern countries due to their low rates of lymph node metastasis (LNM); however, there is a paucity of evidence in Western countries. We investigated LNM and its effect on overall survival (OS) in Western patients with EGC. METHODS: Patients diagnosed with T1 gastric cancer between 2000 and 2017 were retrospectively evaluated. Univariate Kaplan-Meier, multivariate logistic and Cox-regression models were used to assess the associations between clinical characteristics, LNM, and OS. RESULTS: Among 86 patients, median age was 68 years and 72% were male. Node positivity was 30%. Two percent of patients met the classical guidelines for ER and all were node-negative, while 16% met expanded criteria of which 14% were node-positive. T1b disease (odds ratio [OR] 41.2 [95% confidence interval [CI] 1.62-1048], p = 0.02) and lymphovascular/perineural invasion (OR 18.0 [95% CI 2.41-134], p = 0.01) were predictive of node positivity. The 5-year OS for node-negative and node-positive patients was 84% and 53% (p = 0.004), respectively. CONCLUSIONS: The risk of LNM in Western patients with EGC is higher; therefore, generalizability of the expanded criteria for ER should be interpreted with caution.

Intraoperative frozen section analysis of margin status as a quality indicator in gastric cancer surgery.

INTRODUCTION: Positive pathologic margins following gastric cancer (GC) resection carries a poor prognosis. We evaluated intraoperative frozen section (IFS) analysis of resection margins (RMs) as a quality indicator in GC surgery. METHODS: Patients referred to a provincial cancer agency with surgically resected non-metastatic GC between 2004 and 2012 were included. Associations between IFS analysis, other baseline characteristics, RMs, and overall survival (OS) were assessed using logistic regression, Kaplan-Meier analyses, and Cox proportional hazards modeling. RESULTS: Among 377 patients, median age was 67 years, 68% were male, and 16% had +RMs. Thirty-four percent of patients underwent IFS analysis, which protected against +RMs (odds ratio [OR]: 0.34, 95% confidence interval [CI]: 0.16-0.73, p = 0.006) and improved OS (hazards ratio [HR]: 0.72, 95% CI: 0.54-0.98, p = 0.037). OS following re-resection of IFS positive patients was similar to IFS negative patients (69 vs. 54 months, p = 0.317). Stage III disease (OR: 12.8, 95% CI: 3.00-55.0, p = 0.001) and gastroesophageal junction tumors (OR: 2.25, 95% CI: 1.05-4.78, p = 0.036) predicted +RMs. Stage III disease led to worse OS (HR: 2.89, 95% CI: 1.92-4.34, p < 0.001) while intestinal histology improved OS (HR: 0.67, 95% CI: 0.50-0.90, p = 0.007). CONCLUSIONS: IFS analysis reduce +RMs and improve OS and should be incorporated in curative intent GC surgery for patients with locally advanced GC.

Effects of super-class cannabis terpenes beta-caryophyllene and alpha-pinene on zebrafish behavioural biomarkers.

Terpenes possess a wide range of medicinal properties and are potential therapeutics for a variety of pathological conditions. This study investigated the acute effects of two cannabis terpenes, ß-caryophyllene and α-pinene, on zebrafish locomotion, anxiety-like, and boldness behaviour using the open field exploration and novel object approach tests. ß-caryophyllene was administered in 0.02%, 0.2%, 2.0%, and 4% doses. α-pinene was administered in 0.01%, 0.02%, and 0.1% doses. As α-pinene is a racemic compound, we also tested its (+) and (-) enantiomers to observe any differential effects. ß-caryophyllene had only a sedative effect at the highest dose tested. α-pinene had differing dose-dependent effects on anxiety-like and motor variables. Specifically, (+)-α-pinene and (-)-α-pinene had significant effects on anxiety measures, time spent in the thigmotaxis (outer) or center zone, in the open field test, as well as locomotor variables, swimming velocity and immobility. (+ /-)-α-pinene showed only a small effect on the open field test on immobility at the 0.1% dose. This study demonstrates that α-pinene can have a sedative or anxiolytic effect in zebrafish and may have different medicinal properties when isolated into its (+) or (-) enantiomers.

Lymph node mapping in gastric cancer: a pilot study in Western patients.

In East Asia, the role of lymph node (LN) mapping in assisting surgical lymphadenectomy, which is integral to the management of gastric cancer, has been explored. We sought to evaluate its safety and utility in Western patients. Thirteen patients with nonmetastatic gastric adenocarcinoma received endoscopic, peritumoural, submucosal indocyanine green fluorescence (ICG) injections before surgery, and ICG was assessed intraoperatively using a laparoscopic detection system. All patients underwent a laparoscopic subtotal gastrectomy, and 10 of them received D2 lymphadenectomies. ICG-mapped LNs fell outside the D1 distribution in all cases, outside the D1+ distribution in 54%, and within the D2 distribution in all cases. There were no ICG-related allergies, procedural complications, or perioperative deaths. We conclude that ICG LN mapping is safe and feasible in assisting LN dissections and localizing the primary tumour in Western patients. D2 dissections should be performed in patients with advanced gastric cancer, as LNs drained outside the D1/D1+ distributions in most cases.

Predictors of Small Bowel Obstruction Post-Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy.

BACKGROUND: Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) for peritoneal malignancies carries considerable morbidity; however, the significance of postoperative small bowel obstruction (SBO) is not well defined. We aim to identify predictors for post-CRS/HIPEC SBO and their oncologic associations. METHODS: A retrospective review was conducted of all CRS/HIPEC cases performed at a surgical oncology center (2013-2018). Patient demographics, tumor characteristics, perioperative factors, and province-wide hospital readmissions were analyzed. Descriptive statistics were used for baseline characteristics, multivariate logistic regression for predictors of SBO at 1 year, and Kaplan-Meier method with log-rank test for survival analysis. RESULTS: A total of n = 97 CRS/HIPEC procedures were performed for diagnoses of low-grade appendiceal mucinous neoplasm (44%), high-grade appendiceal adenocarcinoma (8%), colorectal adenocarcinoma (34%), and mesothelioma (9%). The median peritoneal carcinomatosis index (PCI) score was 16. Cumulative incidence of post-CRS/HIPEC SBO readmission was 24% at 1 year and 38% at 2 and 3 years. Of 29 patients readmitted with SBO, 14 (48%) had more than one readmission for SBO, and nine surgeries were performed for obstruction. Multivariate regression identified significant independent predictors of SBO within 1-year post-CRS/HIPEC as high-grade appendiceal or colorectal primaries (odds ratio [OR] 4.58, p = 0.02) and PCI ≥ 20 (OR 3.27, p = 0.05). Overall survival (OS) was worse in patients readmitted with SBO within 1 year compared to those without (3-year OS 58% vs. 75%, p = 0.017). CONCLUSION: SBO is the most common readmission diagnosis post-CRS/HIPEC and is associated with worse survival. High-grade appendiceal and colorectal primary tumors and PCI ≥ 20 are predictors for SBO.

Emergency surgical consultation for cancer patients: identifying the prognostic determinants of health.

BACKGROUND: Patients with malignancy often require urgent surgical consultation for treatment or palliation of disease. The objective of this study is to explore the prognostic determinants affecting care in acute cancer-related surgical presentations and the effect on patient outcomes. MAIN BODY: This is a retrospective review of patients referred to the acute general surgery (ACS) service at a tertiary hospital for management of cancer-related problem from July 2017 to September 2018. Patient demographics, course in hospital, and survival were recorded. Multivariant logistic regression and Kaplan-Meier estimates were performed. One hundred eighty-nine patients were identified (53% female) with a mean age of 65.9 years. Forty-two patients (22%) were newly diagnosed with cancer on presentation, and 94 (50%) patients had metastatic disease. Cancer staging was completed in 84% of patients, and 65% had multidisciplinary team (MDT) assessment during their hospital stay. Surgery was performed on 90 (48%) patients, of which 31.2% was with palliative intent. Overall mortality was 56% with 30- and 60-day mortality of 15% and 22%, respectively. The adjusted odds ratio (OR) for a 60-day mortality was high in patients presenting with new cancer diagnosis (OR 3.18, 95% CI 1.18-9.02, p=0.03), metastatic disease (OR 5.11, 95% CI 2.03-12.85, p=0.001), or systemic therapy on presentation (OR 3.46, 95% CI 1.30-9.22, p=0.013). CONCLUSION: Emergency surgical referral is common in patients with malignancy. Surgical decision making can be challenging due to the heterogeneity of this population and their associated comorbidities. Optimizing prognostic determinants such as goal-directed palliative care, MDT discussions, and bridging to systemic therapy can improve patient outcomes.

Population-based assessment of sentinel lymph node biopsy in the management of cutaneous melanoma.

BACKGROUND: Sentinel lymph node biopsy (SLNB) for melanoma plays a central role in determining prognosis and guiding treatment and surveillance strategies. Despite widely published guidelines for SLNB, variation exists in its use. We aimed to determine the frequency of and predictive factors for SLNB in patients with clinically node-negative melanoma in British Columbia. METHODS: A retrospective review was performed of patients with clinically node-negative melanoma diagnosed between January 2015 and December 2017. Patients included had a Breslow depth greater than 0.75 mm or a Breslow depth less than or equal to 0.75 mm with ulceration, or a mitotic rate greater than or equal to 1/mm2. SLNB was considered to be indicated for clinical stages IB to IIC (American Joint Committee on Cancer's AJCC Cancer Staging Manual, seventh edition). RESULTS: A total of 759 patients were included. SLNB was performed in 54.8% (363/662) of patients when indicated. SLNB was more likely to be performed for tumours with a Breslow depth greater than 1.0 mm or a mitotic rate greater than or equal to 1/mm2. SLNB was less likely to be performed in patients older than 75 years and with a nonextremity tumour location. Compliance with SLNB guidelines decreased distant recurrence but did not significantly affect regional recurrence, nor did it have a significant impact on overall survival among patients aged 75 years and younger. CONCLUSION: SLNB is being underutilized in British Columbia. These results are concerning and highly relevant given the rapidly evolving field of adjuvant systemic therapy for high-risk patients and the increased proportion of patients who should be considered for SLNB on the basis of the eighth edition of the AJCC Cancer Staging Manual and current guidelines. Efforts should be made to increase the use of SLNB in appropriate patients.

A Case Series of Metastatic Malignant Gastrointestinal Neuroectodermal Tumors and Comprehensive Genomic Profiling Analysis of 20 Cases.

Malignant gastrointestinal neuroectodermal tumor (GNET) is an ultra-rare soft tissue sarcoma, therefore often misdiagnosed and has no available standard treatment. Here, we report 3 cases of metastatic GNET with variable clinical courses. Our small case series as well as extensive literature review, further support that GNET is a spectrum of diseases with variable inherent biology and prognosis. Surgical management in the setting of recurrent/metastatic disease may be appropriate for GNET with indolent nature. Response to systemic treatments including chemotherapy and targeted treatments is variable, likely related to heterogenous biology as well. Furthermore, we retrospectively identified 20 additional GNET cases from Foundation Medicine's genomic database and expanded on their clinicopathological and genomic features. Comprehensive genomic profiling (CGP) with DNA and RNA sequencing of this cohort, in the course of clinical care, demonstrated recurrent EWSR1 chromosomal rearrangements and a sparsity of additional recurrent or driver genomic alterations. All cases had low tumor mutational burden (TMB) and were microsatellite stable.