Multi-institutional Retrospective Review Research Articles

High-Risk Patients Undergoing Holmium Laser Enucleation of the Prostate Have Fewer Infections with a Longer Course of Preoperative Antibiotics.

Introduction: There are minimal data to guide antibiotic management of patients undergoing holmium laser enucleation of the prostate (HoLEP) for benign prostatic hyperplasia. Specifically, management of high-risk patients who are catheter dependent or have positive preoperative urine cultures varies widely. We aimed to evaluate the effect of preoperative antibiotic duration on infectious complications in high-risk patients undergoing HoLEP. Methods: A multi-institutional retrospective review of patients undergoing HoLEP between 2018 and 2023 at five institutions was performed. Patients were defined as high risk if they were catheter-dependent (indwelling urethral catheter, self-catheterization, or suprapubic tube) or had a positive preoperative urine culture. These patients were categorized into long course (>3 days) or short course (≤3 days) of preoperative antibiotics. The primary outcome was 30-day infectious complications defined as a positive urine culture with symptoms. A t-test or Wilcoxon rank-sum test was used for continuous variables and Fisher's exact test was used for categorical variables. Logistic regression analysis was conducted to identify associations with infectious complications. Results: Our cohort included 407 patients, of which 146 (36%) and 261 (64%) were categorized as short course and long course of preoperative antibiotics, respectively. Median preoperative antibiotic duration was 1 day (interquartile range [IQR]: 0, 3 days) and 7 days (IQR: 5, 7 days) in the short and long cohorts, respectively. Thirty-day postoperative infectious complications occurred in 11 (7.6%) patients who received a short course of antibiotics and 5 (1.9%) patients who received a long course of antibiotics (odds ratio 0.24, 95% confidence interval 0.07-0.67; p = 0.009). Variables such as age, positive urine culture, and postoperative antibiotic duration were not significantly associated with postoperative infection after propensity score weighting. Conclusion: In high-risk patients undergoing HoLEP, infectious complications were significantly lower with a long course vs short course of antibiotics. Further prospective trials are needed to identify optimal preoperative antibiotic regimens.

Multi-institutional review of characteristics and management of gunshot wounds to the spine

BACKGROUND CONTEXTGunshot wounds (GSWs) to the vertebral column represent an important cause of morbidity and mortality in the United States, constituting approximately 20% of all spinal injuries. The management of these injuries is an understudied and controversial topic, given its heterogeneity and lack of follow-up data. PURPOSETo characterize the management and follow-up of GSWs to the spine. STUDY DESIGN/SETTINGA multi-institutional retrospective review of the experience of two urban Level 1 trauma centers. PATIENT SAMPLEPatients with GSWs to the spine between 2010–2021. OUTCOME MEASURESMeasures included work status, follow-up healthcare utilization, and pain management were collected. METHODSCharts were reviewed for demographics, injury characteristics, surgery and medical management, and follow-up. Statistical analysis included T-tests and ANOVA for comparisons of continuous variables and chi-square testing for categorical variables. All statistics were performed on SPSS v24 (IBM, Armonk, NY). RESULTSA total of 271 patients were included for analysis. The average age was 28 years old, 82.7% of patients were black, 90% were male, and 76.4% had Medicare/Medicaid. The thoracic spine (35%) was most commonly injured followed by lumbar (33.9%) and cervical (25.6%). Cervical GSW was associated with higher mortality (p<.001); 8.7% of patients developed subsequent osteomyelitis/discitis, 71.3% received prophylactic antibiotics, and 56.1% of cervical GSW had a confirmed vertebral or carotid artery injury. ASIA scores at presentation were most commonly A (26.9%), D (20.7%), or E (19.6%), followed by C (7.4%) and B (6.6%). 18.8% of patients were unable to be assessed at presentation. ASIA score declined in only 2 patients, while 15.5% improved over their hospital stay. Those who improved were more likely to have ASIA B injury (p<.001). Overall, 9.2% of patients underwent spinal surgery. Of these, 33% presented as ASIA A, 21% as ASIA B, 29% as ASIA C, and 13% as ASIA D. Surgery was not associated with an improvement in ASIA score. CONCLUSIONSGiven the ubiquitous and heterogeneous experience with GSWs to the spine, rigorous attempts should be made to define this population and its clinical and surgical outcomes. Here, we present an analysis of 11 years of patients presenting to two large trauma centers to elucidate patterns in presentation, management, and follow-up. We highlight that GSWs to the cervical spine are most often seen in young black male patients. They were associated with high mortality and high rates of injury to vertebral arteries and that surgical intervention did not alter rates of discitis/osteomyelitis or propensity for neurologic recovery; moreover, there was no incidence of delayed spinal instability in the study population.

Eyeing Risks: A Critical Analysis of the Use of Periorbital Steroids in Fronto-orbital Advancement.

To evaluate the outcomes associated with two techniques of periorbital steroid administration in bilateral fronto-orbital advancement (FOA). Multi-institutional retrospective chart review. Two high volume, tertiary US craniofacial centers. Patients who underwent FOA between 2012 and 2021. Patients were divided into three cohorts based on method of steroid administration. Groups GEL and INJ represent those who received steroids in the form of triamcinolone soaked gelfoam or direct injection of dilute triamcinolone to the frontal/periorbital region, respectively. Group NON did not receive any periorbital steroids. Peri-operative outcomes including hospital length of stay and complications were evaluated based on method of periorbital steroid administration. Variables predictive of infectious complications were assessed using stepwise logistic regression. Four hundred and twelve patients were included in our sample (INJ:249, GEL:87, NON:76). Patients in the INJ group had a higher ASA class (P < .001) while patients in the NON group were significantly more likely to be syndromic (P < .001) and have multisuture craniosynostosis (P < .001). Rate of infectious complications for each cohort were NON: 2.6%, INJ: 4.4%, and GEL: 10.3%. There was no significant difference between groups in hospital length of stay (P = .654) or rate of post-operative infectious complications (P = .061). Increased ASA class (P = .021), increased length of stay (P = .016), and increased intraoperative narcotics (P = .011) were independent predictors of infectious complications. We identified a dose-dependent relationship between periorbital steroids and rate of postoperative infections, with key contributions from ASA class, hospital length of stay, and dose of intraoperative narcotics.

MRI and pathology comparisons in Rasmussen’s encephalitis: a multi-institutional examination of hemispherotomy outcomes relative to imaging and histological severity

PurposeRasmussen encephalitis (RE) is a very rare chronic neurological disorder of unilateral inflammation of the cerebral cortex. Hemispherotomy provides the best chance at achieving seizure freedom in RE patients, but with significant risks and variable long-term outcomes. The goal of this study is to utilize our multicenter pediatric cohort to characterize if differences in pathology and/or imaging characterization of RE may provide a window into post-operative seizure outcomes, which in turn could guide decision-making for parents and healthcare providers.MethodsThis multi-institutional retrospective review of medical record, imaging, and pathology samples was approved by each individual institution’s review board. Data was collected from all known pediatric cases of peri-insular functional hemispherotomy from the earliest available electronic medical records. Mean follow-up time was 4.9 years. Clinical outcomes were measured by last follow-up visit using both Engel and ILAE scoring systems. Relationships between categorical and continuous variables were analyzed with Pearson correlation values.ResultsTwenty-seven patients met study criteria. No statistically significant correlations existed between patient imaging and pathology data. Pathology stage, MRI brain imaging stages, and a combined assessment of pathology and imaging stages showed no statistically significant correlation to post-operative seizure freedom rates. Hemispherectomy Outcome Prediction Scale scoring demonstrated seizure freedom in only 71% of patients receiving a score of 1 and 36% of patients receiving a score of 2 which were substantially lower than predicted.ConclusionsOur analysis did not find evidence for either independent or combined analysis of imaging and pathology staging being predictive for post peri-insular hemispherotomy seizure outcomes, prompting the need for other biomarkers to be explored. Our data stands in contrast to the recently proposed Hemispherectomy Outcome Prediction Scale and does not externally validate this metric for an RE cohort.

Outcomes of Pediatric Proximal Phalanx Base Fractures.

Extra-articular juxtaphyseal fractures of the proximal phalanx are among the most common finger fractures in children. Immobilization of the digit for 3 to 4 weeks after reduction of the fracture is the current standard of care. The purpose of this retrospective study was to evaluate outcomes after intervention among pediatric proximal phalanx base fractures and establish radiographic criteria to guide management. A multi-institutional retrospective review of skeletally immature patients treated for proximal phalanx juxtaphyseal fractures between 2002 and 2019 was conducted. Variables collected included Salter-Harris classification; initial, postreduction, early follow-up, and final angulation and displacement on the posterior-anterior and lateral radiographs; clinical rotational deformity at final follow-up; and method of treatment. Exclusion criteria included less than 3 weeks of follow-up; Salter-Harris III, IV, and V fractures; inadequate medical record details; and missing radiographs. Six hundred thirty-four fractures meeting the inclusion criteria were categorized into no reduction, closed reduction (CR), and surgical (OP) groups. Only CR and OP groups saw large decreases in angulation by 11.8° CR (95% confidence interval, 10.1 to 13.6) and 19.0° OP (95% confidence interval, 8.7 to 29.3). Closed reduction patients had a mean coronal angulation value of 6.1° at post-reduction, which was maintained with immobilization to 5.8° at final follow-up. At final follow-up, scissoring was noted, three in the no reduction and three in the CR group for an overall 0.93% rotational malalignment rate. Extra-articular proximal phalanx juxtaphyseal fractures rarely require surgical management and can typically be treated with or without CR, based on the degree of deformity, in the emergency department or clinical setting. Low rates of documented sequelae after nonsurgical management were seen in this cohort, allowing for establishment of treatment parameters that can result in clinically insignificant angular and rotational deformity. Therapeutic IV.

A Multi-Institutional Study Comparing Stoma Location in Neonates With Intestinal Perforation

IntroductionNeonates with intestinal perforation often require laparotomy and intestinal stoma creation, with the stoma placed in either the laparotomy incision or a separate site. We aimed to investigate if stoma location is associated with risk of postoperative wound complications. MethodsA multi-institutional retrospective review was performed for neonates ≤3 mo who underwent emergent laparotomy and intestinal stoma creation for intestinal perforation between January 1, 2009 and April 1, 2021. Patients were stratified by stoma location (laparotomy incision versus separate site). Outcomes included wound infection/dehiscence, stoma irritation, retraction, stricture, and prolapse. Multivariable regression identified factors associated with postoperative wound complications, controlling for gestational age, age and weight at surgery, and diagnosis. ResultsOverall, 79 neonates of median gestational age 28.8 wk (interquartile range [IQR]: 26.0-34.2 wk), median age 5 d (IQR: 2-11 d) and median weight 1.4 kg (IQR: 0.9-2.42 kg) had perforated bowel from necrotizing enterocolitis (40.5%), focal intestinal perforation (31.6%), or other etiologies (27.8%). Stomas were placed in the laparotomy incision for 41 (51.9%) patients and separate sites in 38 (48.1%) patients. Wound infection/dehiscence occurred in 7 (17.1%) neonates with laparotomy stomas and 5 (13.2%) neonates with separate site stomas (P = 0.63). There were no significant differences in peristomal irritation, stoma retraction, or stoma stricture between the two groups. On multivariable regression, separate site stomas were associated with increased likelihood of prolapse (odds ratio 6.54; 95% confidence interval: 1.14-37.5). ConclusionsStoma incorporation within the laparotomy incision is not associated with wound complications. Separate site stomas may be associated with prolapse. Patient factors should be considered when planning stoma location in neonates undergoing surgery for intestinal perforation.

Abstract No. 9 One-Year Follow-Up of Percutaneous Cholangioscopy-Assisted Rigid ShockPulse Lithotripsy for Inoperable Calculous Cholecystitis: A Multi-institutional Retrospective Review

Abstract No. 9 One-Year Follow-Up of Percutaneous Cholangioscopy-Assisted Rigid ShockPulse Lithotripsy for Inoperable Calculous Cholecystitis: A Multi-institutional Retrospective Review

Urine cytology in the detection of renal cell carcinomas - a territory-wide multi-institutional retrospective review of more than 2 decades.

Compared with urothelial lesions of the upper urinary tract, the diagnostic performance of urine cytology in detection of renal cell carcinomas is underreported. This study aims to establish the role of urine cytology in the assessment of renal carcinomas by a multi-institute review of urine cytology from nephrectomy confirmed renal cell carcinomas, referenced against renal urothelial and squamous cell carcinomas. Records of nephrectomy performed from the 1990s to 2020s at three hospitals were retrieved and matched to urine cytology specimens collected within 1year prior. Patient demographics, specimen descriptors, and histology and staging parameters were reviewed and compared against cytologic diagnoses. There were 1147 cases of urine cytology matched with renal cell carcinomas, with 666 renal urothelial/squamous carcinomas for comparison. The detection rate for urothelial/squamous (atypia or above [C3+]: 63.1%; suspicious or above [C4+]: 24.0%) were higher than renal cell carcinoma (C3+: 13.1%; C4+: 1.5%) (p<0.001). The positive rate for upper tract urine exceeded other collection methods at 45.0% (C3+) and 10.0% (C4+) (p<.01). Other factors associated with increased positive rates were male sex, collecting duct carcinoma histology, nuclear grade, and renal/sinus involvement (p<.05). Multivariate analysis revealed additional positive correlations with presence of sarcomatoid tumor cells, lymphovascular invasion, and perinephric fat involvement (p<.05). Larger lesion size and higher urine volume did not improve detection rates (p<.05). The detection rate of renal cell carcinomas is suboptimal compared with urothelial carcinomas, although urine samples collected from cystoscopy or percutaneous nephrostomy significantly outperformed voided urine specimens.

The spectrum of malignant diagnoses in cerebrospinal fluid cytology from an adult population: a multi-institutional retrospective review

IntroductionLimited updated literature exists about the prevalence and spectrum of malignancies involving cerebrospinal fluid (CSF). In this multi-institutional study, we review our experience with focus on first time malignancy diagnosis in CSF samples of adults. Materials and MethodsInstitutional databases at 4 academic centers were queried retrospectively for CSFs over a 10-year period. The following data elements were collected: total # of CSFs, total # of CSFs with a malignant diagnosis; for each patient with a first time CSF diagnosis of malignancy: age, gender, diagnosis, prior history of malignancy and ancillary studies. Results24142 CSFs were collected with a positive for malignancy rate of 2.3% (n=551). Out of 347 (1.4%) adults with a first-time diagnosis of CSF malignancy 182 (52%) were female (age range: 19-89/mean: 57) and 165 (48%) were male (age range: 20-95/mean: 60). Hematolymphoid malignancies (48%, n=168) were overall the most common neoplasm. In women, metastatic carcinomas (63%, n=114) were the leading malignancy, of which the majority were breast primaries. In men, lymphomas/leukemias (64%, n=106) were the leading malignancy, of which the majority were B-cell lymphomas. Ancillary studies aided the final diagnosis in 110 (32%) cases. For 286 (82%) cases, a prior history of malignancy was available to correlate CSF findings. ConclusionsA malignancy diagnosis in the CSF of adults is rare. The most common malignancies in females and males are metastatic breast carcinoma and hematolymphoid malignancies, respectively. Metastatic neoplasms account for the majority, with primary CNS neoplasms being quite uncommon. History of malignancy and ancillary tests can be helpful.

Transcriptomic Heterogeneity of Metastatic Disease Timing within Metastatic Castration-Sensitive Prostate Cancer

Metastatic castration-sensitive prostate cancer (mCSPC) is commonly partitioned into high- and low-volume subgroups which have demonstrated differential biology, prognosis, and response to therapy. Timing of metastasis has similarly demonstrated differences in clinical outcomes, however less is known about any potential underlying biologic differences between these disease states. Herein we aim to compare transcriptomic differences between synchronous and metachronous mCSPC and identify any differential responses to therapy. We performed an international multi-institutional retrospective review of men with mCSPC who completed RNA expression profiling evaluation of their primary tumor. Patients were stratified according to disease timing (synchronous vs metachronous). The primary endpoint was to identify differences in transcriptomic profiles between disease time. Median genomic scores between groups were compared with Mann-Whitney U test. Secondary analyses included determining clinical and transcriptomic variables associated with overall survival (OS) from time of metastasis. Survival analysis was performed with the Kaplan-Meier Method and Multivariable Cox regression. A total of 252 patients were included with a median follow-up of 39.6 months. Patients with synchronous disease experienced worse 5-yr OS (39% vs 79%, p<0.01) and demonstrated lower median Androgen Receptor Activity (AR-A) (11.78 vs 12.64, p<0.01) and Hallmark Androgen Response (HAR) (3.15 vs 3.32; p<0.01). Multivariable cox-regression identified only high-volume disease (HR = 4.97, 95% CI 2.71-9.10; p<0.01) and HAR score (HR = 0.51, 95% CI 0.28-0.88; p = 0.02 significantly associated with OS. Finally, patients with synchronous (HR = 0.47, 95% CI 0.30-0.72; <0.01) but not metachronous (HR = 1.37, 95% CI 0.50-3.92; p = 0.56) disease were found to have better OS with Androgen Receptor (AR) + non-AR combination therapy as compared to monotherapy (p value for interaction = 0.05). We have demonstrated a potential biologic difference between metastatic timing of mCSPC. Specifically, for patients with low volume disease, those with metachronous low volume disease have a more hormone dependent transcriptional profile and exhibit a better prognosis than synchronous low volume disease.

Is there an OAHI or O2 nadir that predicts the need for preoperative echocardiogram prior to adenotonsillectomy for childrenwith severe obstructive sleep apnea?

To investigate threshold values for obstructive apnea-hypopnea index (OAHI) and nadir oxygen saturation (NspO2) in children with severe obstructive sleep apnea (OSA) to identify children most appropriate for preoperative echocardiography. A multi-institutional retrospective chart review was performed on children who underwent echocardiography and polysomnogram within a year. Children with severe OSA as defined by OAHI > 10 or NspO2 < 80% were included. Receiver operator curves and Youden's J index were used to assess the discriminatory ability and threshold values of OAHI and NspO2 for right heart strain (RHS) on echocardiography. A total of 173 prepubertal (< 10years) children and 71 postpubertal (≥ 10years) children of age were included. RHS was seen in 9 (5%) prepubertal children and 4 (6%) postpubertal children. In prepubertal children, OAHI and NspO2 were poor predictors of RHS (area under the curve [AUC] 0.53 [95%CI 0.45-0.61], p = 0.748; AUC 0.56 [95%CI 0.48-0.64], p = 0.609). In postpubertal children, threshold values of 55 events/hour and 69% were strong predictors for RHS (AUC 0.88 [95%CI 0.78-0.95], p < 0.001; AUC 0.92 [95%CI 0.83-0.97], p < 0.001). In children with severe OSA, evidence of RHS is low. Postpubertal children with OAHI > 55 and NspO2 < 69% appear most appropriate for echocardiography. Clinicians should weigh the risks and benefits of preoperative echocardiography for each child with these threshold values in mind.

Clinical outcomes of radiation therapy for transgender and gender-expansive people with cancer.

Approximately 1.6 million people in the US identify as transgender, many of whom undergo gender-affirming medical or surgical therapies. While transgender individuals are diagnosed with cancer at similar rates as those who are cisgender, the impacts of radiation therapy on outcomes of gender-affirming care in transgender, nonbinary, and gender-expansive people with cancer are understudied. We report on the experiences and outcomes of transgender and gender-expansive patients receiving radiation therapy for cancer treatment. This study is a multi-institutional retrospective review of patients evaluated from 2005-2019 identified as transgender or gender-expansive in the medical record and treated with radiation therapy. We identified 23 patients who received radiation to 32 sites, including 12 (38%) to the brain, head, or neck, 8 (25%) to the thorax, and 7 (22%) to the pelvis. Seventeen patients (74%) received gender-affirming hormone therapy and 13 patients (57%) underwent gender-affirming surgery. Four patients had pelvic radiation before or after gender-affirming pelvic surgery, including two trans women who had pelvic radiation after vaginoplasty. Four patients had radiation to the chest or thorax and gender-affirming chest or breast surgery, including two trans men with breast cancer. Two pediatric patients developed hypopituitarism and hypogonadism secondary to radiation therapy and, as adults, changed their hormone replacement therapy to affirm their transgender identities. Transgender people with cancer undergo radiation therapy for a wide range of cancers. Understanding their prior gender-affirming medical or surgical treatments and future gender affirmation goals may identify important considerations for their oncologic care.

The Spectrum of Malignant Diagnoses in Cerebrospinal Fluid Cytology from an Adult Population – A Multi-Institutional Retrospective Review

The Spectrum of Malignant Diagnoses in Cerebrospinal Fluid Cytology from an Adult Population – A Multi-Institutional Retrospective Review

42219 Multi-institutional retrospective review of acute generalized exanthematous pustulosis (AGEP) induced by hydroxychloroquine

42219 Multi-institutional retrospective review of acute generalized exanthematous pustulosis (AGEP) induced by hydroxychloroquine

Pelvic Ectopic Kidney Prevalence and Pressure Changes During Cloacal Exstrophy (Omphalocele-Exstrophy-Imperforate Anus-Spinal Defects Syndrome) Closure

To assess the prevalence of pelvic ectopic kidneys (PEK) and compare renal parameters of the PEK to the orthotopic kidney following pubic bone approximation. In four Omphalocele-Exstrophy-Imperforate Anus-Spinal Defects Syndrome (OEIS) patients undergoing second-stage repair with known pelvic and orthotopic kidneys, changes in the renal pelvis pressure (RPP), peak systolic velocity (PSV), and resistive index (RI) were measured in the pelvic and orthotopic kidneys following pubic bone approximation. A paired t-test was performed for analysis. Prevalence was tabulated using a multi-institutional retrospective review. Mean rise in RPP was +26.0 mmHg in the PEK and +10.3 mmHg in the orthotopic kidney (P = .55). One patient had immediate increase in RPP of 66mmHg in the PEK (7mmHg in the orthotopic kidney) which decreased to +17 mmHg in the PEK upon release of the pubic approximation stitch. Mean change in PSV was +67.7 cm/s in the PEK compared to - 25.7 cm/s in the orthotopic kidney (P = .09). Mean change in renal RI was +0.06 in PEK compared to -0.01 in the orthotopic kidney (P = .29). Among 80 OEIS patients, 24 (30%) had a PEK. 3 (4%) had a solitary PEK. During second-stage OEIS closure, we witnessed patterns of higher change in RPP, PSV, and RI of the PEK compared to the orthotopic kidney. Furthermore, PEKs were found in nearly a third of our OEIS patients. Real-time RPP monitoring, especially those with solitary PEK, may aid in the management of OEIS patients during the perioperative period.

Sequential Intravesical Gemcitabine and Docetaxel is an Alternative to Bacillus Calmette-Guérin for the Treatment of Intermediate-risk Non–muscle-invasive Bladder Cancer

Adjuvant treatment with either chemotherapy or bacillus Calmette-Guérin (BCG) is recommended for patients with intermediate-risk (IR) non–muscle-invasive bladder cancer (NMIBC). In this multi-institutional retrospective review, we evaluated oncological outcomes for 182 patients with IR-NMIBC treated with BCG (n = 100) or intravesical sequential gemcitabine and docetaxel (Gem/Doce; n = 82). Median follow-up was 48.6 mo (interquartile range 24.9–70.9). No patient had a previous diagnosis of high-grade disease. Recurrence rates were similar in the two treatment groups (hazard ratio [HR] 1.06, 95% confidence interval [CI] 0.65–1.73; p = 0.8). Results were consistent after adjusting for International Bladder Cancer Group (IBCG) risk subgroups, use of single-instillation postoperative chemotherapy, use of blue light cystoscopy, and receipt of maintenance therapy (HR 0.88, 95% CI 0.47–1.64; p = 0.7). Similarly, there was no difference in the rate of stage/grade progression between the treatment groups (HR 0.66, 95% CI 0.21–2.12; p = 0.5). Rates of progression to muscle-invasive disease/metastasis (2.2%) and cancer-specific mortality (1.7%) were low in the cohort. Our results support the use of Gem/Doce as an alternative to BCG in patients with IR-NMIBC. Patient summaryWe compared cancer control outcomes for two different treatments for intermediate-risk non–muscle-invasive bladder cancer. Our results show that a chemotherapy combination of docetaxel and gemcitabine is as effective as the BCG (bacillus Calmette-Guérin) treatment traditionally used for this type of bladder cancer.

Clinical outcomes following intraoperative pedicle disruption in fibula free flaps.

Iatrogenic injury of the fibula free flap pedicle is rare. Postoperative flap survival and reconstructive outcomes following intraoperative pedicle severance are unknown. This study assesses free flap outcomes following accidental severance of the peroneal vessels. Multi-institutional retrospective chart review from 2000 to 2020. Of 2975 harvested fibula free flaps, 26 had a history of pedicle severance during surgical reconstruction. Reasons for intraoperative pedicle severance included transection during muscular dissection 10/26 (39%), accidental severance with the bone saw 12/26 (46%), and other 4/26 (15.6%). The surgeon responsible for pedicle severance included residents 5/26 (19%), fellows 10/26 (39%), attendings 10/26 (39%), and unknown 1/26 (3.9%). The pedicle artery and vein were severed 10/26 (39%), artery 8/26 (31%), and vein 8/26 (31%). Truncated pedicle vessels were used 3/26 (11.7%), intraoperative anastomoses were performed 23/26 (89%). Postoperative revision in the OR within 7 days of surgery was required 6/26 (23%); 4 flaps were salvaged and 2 flaps failed, both arterial thrombosis. Flap failure was attributed to vascular thrombosis. Long-term flap survival and successful reconstructions were reported 24/26 (92%). Accidental severance of fibula free flap pedicle vessels can be corrected with intraoperative repair, without affecting long-term flap survival or reconstructive outcomes. Protecting the flap vessels while using the bone saw and during intramuscular dissection prevents accidental severance.

Transcriptomic heterogeneity of metastatic disease timing within metastatic castration-sensitive prostate cancer.

e17083 Background: Metastatic castration-sensitive prostate cancer (mCSPC) is commonly partitioned into high- and low-volume subgroups which have demonstrated differential biology, prognosis, and response to therapy. Timing of metastasis has similarly demonstrated differences in clinical outcomes, however less is known about any potential underlying biologic differences between these disease states. Herein we aim to compare transcriptomic differences between synchronous and metachronous mCSPC and identify any differential responses to therapy. Methods: We performed an international multi-institutional retrospective review of men with mCSPC who completed RNA expression profiling evaluation of their primary tumor. Patients were stratified according to disease timing (synchronous vs metachronous). The primary endpoint was to identify differences in transcriptomic profiles between disease time. Median genomic scores between groups were compared with Mann-Whitney U test. Secondary analyses included determining clinical and transcriptomic variables associated with overall survival (OS) from time of metastasis. Survival analysis was performed with the Kaplan-Meier Method and Multivariable Cox regression. Results: 252 patients were included with a median follow-up of 39.6 months. Patients with synchronous disease experienced worse 5-yr OS (39% vs 79%, p&lt;0.01) and demonstrated lower median Androgen Receptor Activity (AR-A) (11.78 vs 12.64, p&lt;0.01) and Hallmark Androgen Response (HAR) (3.15 vs 3.32; p&lt;0.01). Multivariable cox-regression identified only high-volume disease (HR=4.97, 95%CI 2.71-9.10; p&lt;0.01) and HAR score (HR=0.51, 95%CI 0.28-0.88; p=0.02 significantly associated with OS. Finally, patients with synchronous (HR=0.47, 95%CI 0.30-0.72; &lt;0.01) but not metachronous (HR=1.37, 95%CI 0.50-3.92; p=0.56) disease were found to have better OS with Androgen Receptor (AR) + non-AR combination therapy as compared to monotherapy (p value for interaction = 0.05). Conclusions: We have demonstrated a potential biologic difference between metastatic timing of mCSPC. Specifically, for patients with low volume disease, those with metachronous low volume disease have a more hormone dependent transcriptional profile and exhibit a better prognosis than synchronous low volume disease. [Table: see text]

Radiation therapy for prostate cancer in Syrian refugees: facing the need for change.

To report the utilization of radiation therapy in Syrian refugee patients with prostate cancer residing in Turkey. A multi-institutional retrospective review including 14 cancer centers in Turkey was conducted to include 137 Syrian refugee patients with prostate cancer treated with radiation therapy (RT). Toxicity data was scored using the National Cancer Institute Common Terminology Criteria for Adverse Events version 3.0. Noncompliance was defined as a patient missing two or more scheduled RT appointments. Advanced disease, defined as stage III or IV, was reported in 64.2% of patients while androgen deprivation therapy (ADT) was only administrated to 20% of patients. Conventionally fractionated RT with a median number of 44 fractions was delivered to all patients with curative intent (n = 61) while palliative RT (n = 76) was delivered with a median number of 10 fractions. The acute grade 3-4 toxicity rate for the entire cohort was 16%. Noncompliance rate was 42%. Most Syrian refugee prostate cancer patients presented with advanced disease however ADT was seldom used. Despite the low treatment compliance rate, conventional fractionation was used in all patients. Interventions are critically needed to improve screening and increase the use of standard-of-care treatment paradigms, including hypofractionated RT and ADT.

Clinical and Genomic Differences Between Advanced Molecular Imaging-detected and Conventional Imaging-detected Metachronous Oligometastatic Castration-sensitive Prostate Cancer

In metastatic castration-sensitive prostate cancer (mCSPC), disease volume plays an integral role in guiding treatment recommendations, including selection of docetaxel therapy, metastasis-directed therapy, and radiation to the prostate. Although there are multiple definitions of disease volume, they have commonly been studied in the context of metastases detected via conventional imaging (CIM). One such numeric definition of disease volume, termed oligometastasis, is heavily dependent on the sensitivity of the imaging modality. We performed an international multi-institutional retrospective review of men with metachronous oligometastatic CSPC (omCSPC), detected via either advanced molecular imaging alone (AMIM) or CIM. Patients were compared with respect to clinical and genomic features using the Mann-Whitney U test, Pearson’s χ2 test, and Kaplan-Meier overall survival (OS) analyses with a log-rank test. A total of 295 patients were included for analysis. Patients with CIM-omCSPC had significantly higher Gleason grade group (p = 0.032), higher prostate-specific antigen at omCSPC diagnosis (8.0 vs 1.7 ng/ml; p < 0.001), more frequent pathogenic TP53 mutations (28% vs 17%; p = 0.030), and worse 10-yr OS (85% vs 100%; p < 0.001). This is the first report of clinical and biological differences between AMIM-detected and CIM-detected omCSPC. Our findings are particularly important for ongoing and planned clinical trials in omCSPC. Patient summaryMetastatic prostate cancer with just a few metastases only detected via newer scanning methods (called molecular imaging) is associated with fewer high-risk DNA mutations and better survival in comparison to metastatic cancer detected via conventional scan methods.