Multi-institutional Retrospective Study Research Articles

Effect of Specimen Extraction Site on Postoperative Incisional Hernia after Minimally Invasive Right Colectomy.

Incisional hernia (IH) is a known complication after colorectal surgery. Despite advances in minimally invasive surgery, colorectal surgery still requires extraction sites for specimen retrieval, increasing the likelihood of postoperative IH development. The objective of this study is to determine the effect of specimen extraction site on the rate of IH after minimally invasive right-sided colectomy for patients with available imaging. This is a retrospective multi-institutional cohort study at 2 large academic medical centers in the US. Adults who underwent right-sided minimally invasive colectomy from 2012 to 2020 with abdominal imaging available at least 1 year postoperatively were included in the analysis. The primary exposure was specimen extraction via a midline specimen extraction vs Pfannenstiel specimen extraction. The main outcome was the development of IH at least 1 year postoperatively as visualized on a CT scan. Of the 341 patients sampled, 194 (57%) had midline specimen extraction and 147 (43%) had a Pfannenstiel specimen extraction. Midline extraction patients were older (66 ± 15 vs 58 ± 16; p < 0.001) and had a higher rate of previous abdominal operation (99, 51% vs 55, 37%, p = 0.01). The rate of IH was higher in midline extraction at 25% (48) compared with Pfannenstiel extraction (0, 0%; p < 0.001). The average length of stay was higher in the midline extraction group at 5.1 ± 2.5 compared with 3.4 ± 3.1 days in the Pfannenstiel extraction group (p < 0.001). Midline extraction was associated with IH development (odds ratio 24.6; 95% CI 1.89 to 319.44; p = 0.004). Extracorporeal anastomosis was associated with a higher IH rate (odds ratio 25.8; 95% CI 2.10 to 325.71; p = 0.002). Patients who undergo Pfannenstiel specimen extraction have a lower risk of IH development compared with those who undergo midline specimen extraction.

PD-L1 Expression and Its Modulating Factors in Anaplastic Thyroid Carcinoma: A Multi-institutional Study.

Anti-PD immunotherapy is currently under investigation in anaplastic thyroid carcinoma (ATC). Tumor cell surface PD-L1 expression is considered predictive of therapeutic response. Although papillary thyroid carcinoma has been widely studied for PD-L1 expression, there are limited data on ATC. In this retrospective multi-institutional study involving 9 centers across Asia, 179 ATCs were assessed for PD-L1 expression using the SP263 (Ventana) clone. A tumor proportion score (TPS) ≥1% was required to consider a case PD-L1-positive. PD-L1 expression was compared with the histological patterns, the type of specimen (small or large), tumor molecular profile (BRAF V600E and TERT promoter mutation status), and patient outcome. PD-L1 expression in any co-existent differentiated thyroid carcinoma (DTC) was evaluated separately and compared with ATC. Most ATCs (73.2%) were PD-L1-positive. The median TPS among positive cases was 36% (IQR 11% to 75%; range 1% to 99%). A high expression (TPS ≥ 50%) was noted in 30.7%. PD-L1-negative cases were more likely to be small specimens (P=0.01). A negative result on small samples, hence, may not preclude expression elsewhere. ATCs having epithelioid and pleomorphic histological patterns were more likely to be PD-L1-positive with higher TPS than sarcomatoid (P<0.01). DTCs were more frequently negative and had lower TPS than ATC (P<0.01). Such PD-L1 conversion from DTC-negative to ATC-positive was documented in 71% of cases with co-existent DTC. BRAF V600E, but not TERT promoter mutations, correlated significantly with PD-L1-positivity rate (P=0.039), reinforcing the potential of combining anti-PD and anti-BRAF V600E drugs. PD-L1 expression, however, did not impact the patient outcome.

Complications and putative risk factors for cecal or colonic surgery in dogs: 79 cases (2002-2015).

To evaluate the complication rate, mortality rate and putative risk factors for cecal or colonic surgery in dogs. A multi-institutional retrospective study including dogs that had undergone surgery that involved the cecum or the colon. Medical records from three referral hospitals were reviewed for patient demographics and clinical data. The association between putative risk factors and survival to discharge or complications was assessed using univariable and multivariable analysis. Seventy-nine dogs met the criteria to be included in this study. Fifty-five dogs had full thickness incision surgeries, while 24 dogs had partial thickness surgeries. The complication and mortality rates for full thickness and partial thickness cecal/colonic surgeries were not statistically different. The dehiscence rate of colonic anastomosis in this study was four of 47 (8.5%). On univariate analysis, performing full thickness procedures out of hours had an association with increased complications and mortality. On multivariable analysis, no factors were associated with survival to discharge or complications. There was no association of board-certified surgeon presence in surgery with complications or mortality. The performance of full thickness cecal/colonic surgery is not associated with a statistically significant increased risk for complications or mortality compared to partial thickness procedures, with a possible increased risk of complications and mortality in full thickness procedures out of hours.

Gamma Knife Radiosurgery for Hypothalamic Hamartoma: A Multi-Institutional Retrospective Study on Safety, Efficacy, and Complication Profile.

Gamma knife radiosurgery (GKRS) is a safe and effective treatment option for hypothalamic hamartomas (HH), but there is no consensus opinion on its timing, dosage, and follow-up. The aim of this study was to define the safety, efficacy, outcome, and complication profile of GKRS in this patient population. This retrospective multicentric study involved 39 patients with the mean age of 16 ± 14.84 years. Early seizures resulted in an earlier age of diagnosis in 97% of patients. At baseline, no endocrine abnormalities were seen in 75% of patients while 18.9% showed precocious puberty (PP). The median target volume was 0.55 cc (0.1-10.00 cc), and a median margin dose of 16 Gy (8.1-20.0 Gy) was delivered in a single session. All patients were evaluated for clinical, endocrinological, and radiological outcomes. The median follow-up was 5 (0.1-15) years. The median target volume of the cohort was 0.55 (0.35-1.77) cc. The largest HH was of 10 cc. 24/39 (61.5%) were small HH (Regis I-III). At presentation, 94.8% patients suffered from seizures (87.18% with gelastic seizures). 7/39 patients (17.9%) were presented with both PP and epilepsy. Only one (2.6%) patient presented with PP alone. 29 patients had more than 3-year follow-up. All received ≥16 Gy targeting complete HH. 28% of patients showed regression in HH volume. Patients with Regis grade I-III and longer follow-up (>75 months) showed gradual improvement in seizures. 16/29 patients (55.2%) achieved good seizure control (Engel I/II) while 13 (44.8%) were in Engel III/IV status. Nine patients needed adjuvant treatment because of poor seizure control. Eight patients suffered from transient increase in seizures. One patient developed poikilothermia, and 2 patients developed new onset hormonal deficiency. GKRS is a safe and effective modality for treatment of HH with significant improvement in seizure control with minimal disruption of endocrine profile. It provides an excellent safety, efficacy, and complication profile, especially for small HH. Latency of results and its adjuvant nature remain the areas of research and breakthroughs among contemporary treatment options.

Impact of Margin Status on Local Recurrence in Patients with Breast Cancer Undergoing Breast-Conserving Surgery After Neoadjuvant Chemotherapy: A Retrospective Multi-Institutional Cohort Study.

Questions have been raised as to an increased risk of local recurrence with breast-conserving surgery (BCS) post NAC highlighting the uncertainty around optimal margin width in this patient population. We examined the association between margin status and local recurrence-free survival (LRFS) in patients who underwent BCS following NAC. We performed a retrospective cohort study of adult female patients with stage I-III breast cancer who underwent NAC followed by BCS between 2012 and 2021 at two cancer centers. Margins were categorized as "close" if they were < 1 mm. The full cohort included 544 patients with a median age of 53 years (interquartile range [IQR] 44-64). Pathologic complete response (pCR) was achieved in 41.2% of the overall cohort (n = 224). Of the 320 with residual disease, 29.4% (n = 94) had at least one close margin, and 10.9% (n = 35) had ≥2 close margins. Median follow-up was 55 months (IQR 32-83); 4.8% had an ipsilateral breast recurrence (n = 26). Patients with pCR had a higher 5-year LRFS than those with residual disease (98.0% vs. 91.6%, p = 0.02). There was no difference in 5-year LRFS between the margin categories (clear vs. 1 close margin vs. ≥2 close margins) in those with residual disease (92.2% vs. 88.9% vs. 92.9%) (p = 0.78). In patients undergoing BCS post-NAC, those who achieved pCR had a significantly higher LRFS compared with those with residual disease at the time of surgery, but LRFS was not associated with margin width nor the number of close margins.

Radiologic Evaluation of Oral Health Status in Patients Admitted to the Intensive Care Unit: A Multi-Institutional Retrospective Study.

Introduction: Surveys distributed among intensive care unit (ICU) nurses reveal a significant need for dental care, with many acknowledging poor oral hygiene management. Poor oral health in ICU patients is linked to systemic problems, including aspiration pneumonia, necessitating pre-intervention assessments for bacterial diseases and dental risks. This study aims to evaluate the oral health status of ICU patients across three institutions through retrospective analysis. Methods: This retrospective study assessed the oral health status of ICU patients, using computed tomography (CT) images from three institutions over ten years. Through CT images, the oral status was evaluated in terms of total and lost tooth count and the presence of oral lesions (periapical lesions, cysts and tumors, caries, tartar, moderate to severe periodontal bone loss, tooth fractures). Variables included gender, age, the duration of ICU stay, and types of ICU. Statistical analysis was performed using chi-square tests, independent-sample t-tests, and logistic regression analysis. Results: Of the 450 participants, 430 were analyzed, revealing a prevalence of oral lesions in 67.0% of subjects. The prevalence of oral lesions was higher in males (71.5%) than females (57.7%, p = 0.006), and higher in those aged 40 and above (72.1%) compared to those under the age of 40 (47.8%, p < 0.001). This study found significant differences in oral health status based on gender, age, and ICU type, with surgical ICU patients generally having better oral health. Risk factors for oral lesions included gender, age, and duration of ICU stay. Conclusions: Most ICU patients have at least one oral lesion, regardless of the reason for their ICU admission. In particular, male ICU patients aged 40 and above have a higher prevalence of oral lesions, necessitating careful oral health assessment and treatment.

Circulating Tumor DNA Predicts Early Recurrence Following Locoregional Therapy for Oligometastatic Colorectal Cancer.

(1) Background: Local therapies offer a potentially curative approach for patients with oligometastatic colorectal cancer (CRC). An evidence-based consensus recommendation for systemic therapy following definitive locoregional therapy is lacking. Tumor-informed circulating tumor DNA (ctDNA) might provide information to help guide management in this setting. (2) Methods: A multi-institutional retrospective study was conducted, including patients with CRC that underwent curative-intent locoregional therapy to an isolated site of metastatic disease, followed by tumor-informed ctDNA assessment. The Kaplan-Meier method and log-rank tests were used to compare disease-free survival based on ctDNA results. ctDNA test performance was compared to carcinoembryonic antigen (CEA) test results using McNemar's test. (3) Results: Our study cohort consisted of 87 patients treated with locoregional interventions who underwent ctDNA testing. The initial ctDNA test post-intervention was positive in 28 patients and negative in 59 patients. The median follow-up time was 14.0 months. Detectable ctDNA post-intervention was significantly associated with early disease recurrence, with a median disease-free survival (DFS) of 6.63 months compared to 21.30 months in ctDNA-negative patients (p < 0.001). ctDNA detected a numerically higher proportion of recurrences than CEA (p < 0.097). Post-intervention systemic therapy was not associated with improved DFS (p = 0.745). (4) Conclusions: ctDNA results are prognostically important in oligometastatic CRC, and further prospective studies are urgently needed to define its role in guiding clinical decisions.

Laser Acupuncture versus Liraglutide in Treatment of Obesity: A Multi-Institutional Retrospective Cohort Study.

Obesity is a global concern, driving the search for alternative treatments beyond lifestyle changes and medications. Laser acupuncture (LA) shows promise in obesity management, yet few studies compare it with FDA-approved medications. This study aimed to assess and compare LA's impact with liraglutide on weight reduction in obese individuals. Data from the Chang Gung Research Database (CGRD) (2013-2018) were analyzed. Primary outcomes included changes in body weight and BMI within 180 days, with secondary outcomes measuring the proportion achieving 5%, 10%, and 15% weight loss. Adverse events were also assessed. Of 745 subjects (173 LA users, 572 liraglutide users), LA users lost more weight by day 180 (5.82 ± 4.39 vs. 2.38 ± 5.75 kg; p < 0.001) and had a greater BMI reduction (-2.27 ± 1.73 vs. -0.93 ± 2.25 kg/m2; p < 0.001). More LA users achieved 5% and 10% weight loss compared to liraglutide users (64.2% vs. 22.7%, 26.6% vs. 4.2%; all p < 0.001). After balancing baseline differences, LA's benefits remained significant. No adverse events were reported with LA. LA may offer superior weight reduction compared to liraglutide. Future studies should explore LA alone or in combination with liraglutide for obesity management.

Prognosis of isolated locoregional recurrence after early breast cancer with immediate breast reconstruction surgery: a retrospective multi‑institutional study.

The prognosis in patients with breast cancer with isolated locoregional recurrence (ILRR) without simultaneous distant metastases after immediate breast reconstruction (IBR) remains unknown. We aimed to investigate the prognosis in this patient population. This multi-institutional retrospective observational study evaluated 3295 patients with primary breast cancer who underwent IBR at 12 Japanese medical facilities between January 1, 2008 and December 31, 2016. The outcome measures were the prognostic factors for ILRR after IBR, 5-year distant metastasis-free interval (DMFI), and 5-year overall survival (OS). Mastectomy or skin-sparing mastectomy was performed in 3295 patients. ILRR occurred in 70 patients, and the median observation period from ILRR diagnosis was 39.3months. Of the 70 patients, 9 (12.9%) had axillary lymph node recurrence (ALNR) at the time of ILRR diagnosis. The 5-year DMFI and OS rates after ILRR were 92.4% and 91.2%, respectively. Pathological lymph node metastasis at primary surgery (P = 0.041) and ALNR (P = 0.022) at ILRR were significantly associated with DMFI in the univariate analysis. ALNR was the only independent prognostic factor in the multivariate analysis (P = 0.041). Post-mastectomy radiation therapy (PMRT; P = 0.022) and ALNR (P = 0.043) were significantly associated with OS in the univariate analysis, and both PMRT (P = 0.010) and ALNR (P = 0.028) were independent prognostic factors in the multivariate analysis for OS. Although patients with breast cancer who had ILRR after IBR have favorable prognosis, ALNR may lead to poor prognosis. To the best of our knowledge, this study is the first to report the prognosis of these patients.

MDB-58. REDUCED CRANIOSPINAL DOSE FOR NEWLY DIAGNOSED HIGH-RISK MEDULLOBLASTOMA IN CHILDREN YOUNGER THAN 5 YEARS OLD: RETROSPECTIVE EXPERIENCE FROM SFCE

Abstract BACKGROUND High Risk medulloblastoma (MB) treatment strategy is based on an intensive multimodal treatment including surgery, chemotherapy and radiotherapy. French adapted PNET HR +5 is based on high-dose chemotherapy and age-stratified (18 Gy &amp;lt; 3 yo, 23 for 3-5 yo, 36 Gy for &amp;gt; 5 yo) craniospinal dose irradiation to reduce long-term side-effects of radiotherapy. METHODS To estimate progression-free (PFS) in a national multi-institutional retrospective study, we enrolled children younger than 5 yo with newly diagnosed high-risk MB treated according to adapted PNET HR +5 trial. RESULTS Thirty-seven children from 15 French hospitals (median age, 3.4 yo; range, 0.7-4.8) with confirmed high-risk MB were included. 15 patients (39%) were less than 3 years old. 29 patients (81%) had metastatic disease. Group 3 was the most represented molecular subgroup. 5-year PFS and OS was 59 % and 77 %, respectively. According to dose of craniospinal irradiation, PFS for 18 Gy, 23.4 Gy and 36 Gy patient groups were 100 %, 75 % and 45%, respectively. Treatment was well tolerated. One toxic death was declared. Analysis of longitudinal neurocognitive performance is ongoing. CONCLUSIONS the French strategy comprising high-dose chemotherapy and age-adapted craniospinal irradiation is promising with a high rate of survival in young children and must be confirmed by a prospective trial.

Real-World Prevalence and Tolerability of Immune-Related Adverse Events in Older Adults with Non-Small Cell Lung Cancer: A Multi-Institutional Retrospective Study.

With cancer diagnosis occurring at older ages, the use of immune checkpoint inhibitors (ICIs) has extended to older adults. However, the safety of immune-related adverse events (irAEs) in this population remains unclear and relies on data extrapolated from younger adults. This multicenter retrospective study aimed to examine irAE prevalence and tolerability in older adults. We included 436 patients with non-small lung cancer undergoing ICI therapy and dichotomized them into two age groups (< or ≥75 years). Incidence of any irAE grade, grade ≥3 irAEs, and steroid usage after irAE occurrence was similar between younger (n = 332) and older groups (n = 104). While the younger patients with irAEs showed prolonged overall survival in the 12-month landmark Kaplan-Meier analysis (Hazard ratio (HR) 0.59, 95% confidence interval (CI) 0.38-0.89, p = 0.013), the older cohort did not (HR 0.80, 95% CI 0.36-1.78, p = 0.588). Although no differences were observed with ICI continuation or re-challenge after irAE onset, the elderly cohort had double the irAE cases that required a transition to best supportive care (BSC) (11.3% vs. 22.4%, p = 0.026). In conclusion, although irAE prevalence remains consistent regardless of age, the increased conversion to BSC post-irAE onset in older adults suggests diminished tolerability and the potential absence of favorable prognosis associated with irAEs in this population.

Utility of pelvic CT in patients undergoing surveillance for hepatocellular carcinoma: A retrospective multi-institutional study.

To determine the frequency, characteristics and clinical significance of incidental pelvic findings reported on abdominopelvic CT performed for hepatocellular carcinoma (HCC) surveillance in at-risk patients. This two-center retrospective study received institutional review board approval with a waiver of informed consent. The radiologic reports of the CT exams performed 1/1/2010-2/28/2023 for HCC surveillance were reviewed. Exams were obtained with intravenous contrast material and included hepatic arterial and portal venous phases of the abdomen; images of the pelvis were acquired during the portal venous phase. Reported imaging findings and imaging-related recommendations either by the radiologists or the corresponding caregiver, if present, were retrospectively tabulated. The patient's medical records were reviewed to determine if there were any recommendations that were considered clinically important and culminated in any further interventions or treatments. 259 adults (1st center: mean age, 60 ± 11 years, 49% male and 2nd center: 56.26 ± 6.2 years, 48% male) at risk for HCC underwent 327 abdominopelvic CT exams for HCC surveillance at two centers. A total of 622 pelvic findings (mean, 2.2/ exam) were reported, including 131 bladder, 120 alimentary tract, 133 vascular, 51 gynecologic, 37 prostate, 33 lymph node, 27 inguinal, 44 peritoneal, and 46 skeletal. 52 of 622 reported findings (8.3%) were associated with actionable recommendations. 24 of the 52 actionable recommendations/clinical suggestions were implemented as follows: five complimentary imaging, ten additional laboratory tests, and nine non-imaging recommendations. Of note, only eight applied recommendations culminated in a clinical outcome, which included four urinary tract infection treatments. Pelvic CT findings were associated with a clinical benefit to the patient in 1.3% of exams. These results suggest that pelvic imaging should be omitted from CT-based HCC surveillance. Without compromising valuable information, patients undergoing HCC surveillance-CT may not require additional pelvic coverage.

Benefit of perioperative chemotherapy in the patients with loco-regional recurrence of HR-positive HER2-negative breast cancer: A multi-institutional retrospective cohort study.

526 Background: Loco-regional recurrence (LRR) in breast cancer (BC) is addressed with multimodal treatment, yet the prognosis remains unfavorable. The benefit of adjuvant chemotherapy for the hormone receptor-positive, HER2-negative (HR+HER2-) subtype of BC is controversial. Methods: We performed a multi-institutional retrospective cohort study under the Japan Clinical Oncology Group. This study focused on patients without distant metastasis who developed HR+HER2- ipsilateral breast tumor recurrence (IBTR) or other LRR (oLRR) including recurrence in skin, chest wall, or regional lymph nodes. The patients received curative surgery for LRR between 2014 and 2018. Patients were divided into two groups: the chemotherapy group and no chemotherapy group before/after LRR. We performed a Cox proportional hazards model to evaluate invasive disease-free survival (iDFS) between the two groups. Sensitivity analysis was conducted using propensity score (PS) matching and IPTW. Results: A total of 967 patients were registered from 41 institutions, and 958 patients concordant with inclusion criteria were analyzed. There were 509 patients (53%) of only IBTR and 449 patients (47%) of oLRR. Neoadjuvant/Adjuvant chemotherapy was administered to 235 patients (25%), while 722 (75%) did not receive it. Compared to the no-chemotherapy group, the chemotherapy group included a higher number of patients aged 41-60, oLRR, and recurrences during adjuvant endocrine therapy. At a median follow-up of 5.2 years (Interquartile range: 4.1-6.5), the 5-year iDFS rate was 75.4% (95% CI: 72.4-78.2). Multivariate analysis showed an improvement in iDFS for the chemotherapy group (HR: 0.70, 95% CI: 0.49-0.99, p = 0.045). Sensitivity analysis also consistently suggested the effectiveness of chemotherapy (PS matching HR 0.76, IPTW HR 0.75). In the subgroup analysis, the chemotherapy group showed more significant iDFS improvement in cases with oLRR, recurrences during adjuvant endocrine therapy for primary BC, and those without perioperative chemotherapy for primary BC. Conclusions: Our study showed improvement in iDFS in patients who received perioperative chemotherapy for HR+HER2- LRR. This improvement was particularly notable in patients with oLRR, recurrences during adjuvant endocrine therapy, and those without perioperative chemotherapy for primary BC. [Table: see text]

Hepatobiliary Infection after Transjugular Intrahepatic Portosystemic Shunt Creation in Patients with Prior Biliary Intervention: A Multi-Institution Retrospective Study

PurposeTo estimate the risk of hepatobiliary infection, including endoTIPSitis, liver abscesses, and cholangitis, after transjugular intrahepatic portosystemic shunt (TIPS) creation in patients with prior biliary intervention. Materials and MethodsThis multi-institution, retrospective study identified 76 patients (n = 48 males; mean age, 54.9 years; mean Model for End-stage Liver Disease [MELD] score, 13.2; n = 45 for ascites and n = 23 for varices; n = 31 with prior liver transplantation) among 2,130 (3.6%) undergoing TIPS creation who had prior biliary intervention (n = 19 bilioenteric anastomoses, n = 35 sphincterotomies, n = 28 internal plastic stent placements, n = 4 internal metal stent placements, and n = 6 percutaneous biliary drain placements). The baseline risk of post–TIPS creation hepatobiliary infection was estimated from a control group of 1,202 TIPS creation procedures in patients without prior biliary intervention. ResultsEleven (14.5%) of 76 patients developed hepatobiliary infection after TIPS creation, including 7 with endoTIPSitis, 4 with hepatic abscesses, and 2 with cholangitis. The 30-day risk of infection was 10.9% (95% confidence interval [CI], 3.5%–17.8%), significantly higher than the 0.4% risk (95% CI, 0.1%–0.8%) observed in patients without prior biliary intervention (hazard ratio [HR], 25.56; 95% CI, 8.36–78.13; P < .001). All types of biliary intervention were associated with increased risk of infection, with bilioenteric anastomoses conferring the highest risk. Paradoxically, among patients with prior biliary intervention, use of postprocedural antibiotic prophylaxis was associated with an increased infection risk (HR, 19.85; 95% CI, 2.44–161.50; P = .005). Microbial culture data showed high rates of Enterococcus, Klebsiella, and Candida species. ConclusionsPrior biliary intervention was associated with a 10.9% risk of hepatobiliary infection, including endoTIPSitis, liver abscess, and cholangitis, within 30 days after TIPS creation.

Prognosis of deep margin excisions within or beyond subcutaneous fat for invasive acral melanoma of the sole: A multi-institutional retrospective study.

9582 Background: There is scant evidence concerning the optimal deep margins for wide excision (WE) of primary tumors in melanoma surgery. Despite the importance of preserving plantar subcutaneous fat in the sole for cushioning function, no study data exists on the optimal depth margins for acral melanoma of the sole (sole AM). Thus, we aimed to compare the prognosis associated with different deep margin excisions for sole AM. Methods: We conducted a retrospective review of clinical records from patients with invasive resectable sole AM who underwent WE of the primary tumor across 41 Japanese institutions. The prognosis was compared between two groups based on different deep margin excisions: those with tumors excised within (S-group) or beyond (D-group) the subcutaneous fat. Kaplan—Meier analysis and multivariable Cox proportional hazard models were used to estimate the survival probabilities. Propensity-score matching (PSM) was used to adjust for numerical differences in baseline characteristics. Results: This study included a total of 425 patients (median age 73 years) with invasive sole AM, who underwent WE based on the peripheral surgical margins recommended in the National Comprehensive Cancer Network guidelines. The median follow-up period was 48 months. The S-group included 263 patients and the D-group 162 patients. The baseline characteristics significantly differed between the two groups in terms of Breslow thickness ( P &lt; 0.01), presence of ulcer ( P &lt; 0.01), and presence of in-transit, satellite, and regional lymph node metastasis ( P &lt; 0.01). The other baseline characteristics were similar. Although local recurrence-free survival (LRFS) did not significantly differ between groups, the S-group showed significantly longer disease-free (DFS) and overall survival (OS) than the D-group (5-year LRFS, 96% vs. 90%; P = 0.08; 5-year DFS, 70% vs. 41%; P &lt; 0.01; 5-year OS, 84% vs. 69%; P &lt; 0.01). In contrast, multivariable Cox proportional hazard models showed no significant differences in LRFS, DFS, and OS between the two groups (LRFS, hazard ratio [HR], 1.87, P = 0.18; DFS, HR, 1.05, P = 0.77; OS, HR, 1.08, P = 0.72). After PSM, the groups were balanced at a 1:1 ratio (128 patients in each group) and no statistical significance was found in LRFS, DFS, or OS between the adjusted groups (5-year LRFS, 97 % vs. 91 %; P = 0.40; 5-year DFS, 65 % vs. 48 %; P = 0.053; 5-year OS, 80 % vs. 73%; P = 0.18). Subgroup analysis of stage I, II, and III also indicated no statistical significance in LRFS, DFS, and OS between the two groups (stage I: LRFS, P = 0.11; DFS, P = 0.65; OS, P = 0.26; stage II: LRFS, P = 0.37; DFS, P = 0.06; OS, P = 0.85; stage III: LRFS, P = 0.29; DFS, P = 0.67; OS, P = 0.85). Conclusions: In sole AM, WE with excessive deep margins beyond the subcutaneous fat did not improve prognosis. Excision of the primary tumor within the subcutaneous fat may be an optimal deep margin for sole AM.

P.104 Prognostic value of NIRS regional oxygen saturation based cerebrovascular reactivity in TBI: a Canadian high resolution traumatic brain injury (CAHR-TBI) cohort study

Background: Near-infrared spectroscopy regional cerebral oxygen saturation (rSO2) has gained interest as a raw parameter and as a basis for measuring cerebrovascular reactivity (CVR). This study aimed to identify threshold values of rSO2 and rSO2 based CVR at which outcomes worsened following traumatic brain injury (TBI). Methods: A retrospective multi-institutional cohort study was performed. The cerebral oxygen indices, COx (using rSO2 and cerebral perfusion pressure) as well as COx_a (using rSO2 and arterial blood pressure) were calculated for each patient. 2x2 tables were created grouping patients by alive/dead and favorable/unfavorable outcomes at various thresholds of COx and COx_a as well as rSO2 itself. Chi-square values were calculated to identify the most discriminative significant threshold. Results: In the cohort of 129 patients rSO2 did not have any statistically significant threshold value. For COx and COx_a, an optimal threshold value of 0.2 was identified for both survival and favorable outcomes with values above this associated with worse outcomes. Conclusions: In this study, raw rSO2was found to contain no significant prognostic information. However, rSO2 based indices of CVR, were found to have a uniform threshold of 0.2, above which clinical outcomes worsened. This study lays the groundwork to transition to less invasive means of continuously measuring CVR.

Effects of different treatments for type 2 diabetes mellitus on mortality of coronavirus disease from 2019 to 2021 in China: a multi-institutional retrospective study.

The coronavirus disease (COVID-19) pandemic has continued for 5 years. Sporadic cases continue to occur in different locations. Type 2 diabetes mellitus (T2DM) is associated with a high risk of a poor prognosis in patients with COVID-19. Successful control of blood glucose levels can effectively decrease the risks of severe infections and mortality. However, the effects of different treatments were reported differently and even adversely. This retrospective study included 4,922 patients who have been diagnosed as COVID-19 and T2DM from 138 Hubei hospitals. The clinical characteristics and outcomes were compared and calculated their risk for death using multivariate Cox regression and Kaplan-Meier curves. After adjustment of age, sex, comorbidities, and in-hospital medications, metformin and alpha-glucosidase inhibitor (AGI) use performed lower all-cause mortality (adjusted hazard ratio [HR], 0.41; 95% confidence interval [CI]: 0.24-0.71; p = 0.001 for metformin; 0.53, 0.35-0.80, p = 0.002 for AGIs), while insulin use was associated with increased all-cause mortality (adjusted HR, 2.07, 95% CI, 1.61-2.67, p < 0.001). After propensity score-matched (PSM) analysis, adjusted HRs for insulin, metformin, and AGIs associated with all-cause mortality were 1.32 (95% CI, 1.03-1.81; p = 0.012), 0.48 (95% CI, 0.23-0.83, p = 0.014), and 0.59 (95% CI, 0.35-0.98, p = 0.05). Therefore, metformin and AGIs might be more suitable for patients with COVID-19 and T2DM while insulin might be used with caution.

Outcome of video-assisted thoracoscopic treatment of idiopathic chylothorax in 15 cats.

To evaluate the outcomes and complications of video-assisted thoracoscopic (VATS) treatment of chylothorax in cats. Multi-institutional retrospective study. Fifteen client-owned cats. The medical records of cats undergoing thoracoscopic thoracic duct ligation (TDL) for treatment of idiopathic chylothorax were reviewed. Cats undergoing additional procedures including thoracoscopic pericardectomy and/or laparoscopic cisterna chyli ablation (CCA)_were included. Follow up was obtained through communication with the referring veterinarian or owner. All cats underwent thoracoscopic TDL. Thirteen cats underwent simultaneous pericardectomy and two cats underwent laparoscopic CCA without pericardectomy. Conversion from a thoracoscopic to open approach was necessary in 2/15 (13%) of thoracic duct ligations and 1/11 (9%) of pericardectomies. The most common postoperative complication was persistent pleural effusion in five cats (33%). Four of 15 cats (27%) died or were euthanized prior to hospital discharge following surgery. Recurrence of effusion occurred in 1/7 (14%) of cats that sustained resolution of the effusion at the time of surgery with a median follow up of 8 months. The overall mortality attributed to chylothorax was 47%. Thoracoscopic treatment of idiopathic chylothorax resulted in a low incidence of intraoperative complications or conversion in the study population; however, mortality related to feline idiopathic chylothorax remained high. While VATS treatment of idiopathic chylothorax is technically feasible, further consideration of the underlying pathology and current treatment algorithm is needed to improve outcomes as this remains a frustrating disease to treat in the feline population.

Abstract PO3-05-13: A Multi-Institutional Review of Contralateral Axillary Metastases: Time for Reclassification as Local-Regional Event?

Abstract Background Current American Joint Committee on Cancer (AJCC) breast cancer staging considers contralateral axillary metastasis (CAM) stage IV disease (M1). Retrospective studies suggest that women with CAM have improved overall survival (OS) compared to those with distant metastasis (M1) and/or comparable OS to locally advanced breast cancer (LABC). These studies support consideration of curative intent treatment; however, they contain heterogeneous cohorts with highly variable treatment strategies. We sought to evaluate treatment and outcomes in a well-defined CAM cohort treated with contemporary systemic and locoregional therapy. Methods We performed a retrospective multi-institution cohort study to compare OS of patients with CAM matched 1:3 on age +/- 5 years to LABC (defined as cN2-3 and/or pN2-3), and to non-CAM M1. CAM patients classified as type 1) de novo CAM, synchronous with the contralateral primary, 2) metachronous isolated CAM in the setting of prior surgical and/or radiation treatment to primary index cancer, 3) synchronous with, or 4) metachronous after an in-breast or axillary nodal recurrence of the primary index cancer. The M1 cohort included de novo and recurrent metastasis with varied sites and number of metastasis. OS was defined as time from CAM diagnosis to death or last follow-up for CAM patients; time from primary diagnosis to death or last follow-up for LABC; and time from metastatic diagnosis to death or last follow-up for M1. Unadjusted OS was estimated with the Kaplan-Meier method, and Cox proportional hazards models were used to estimate the association of group with OS after adjustment for covariates Results We identified 57 CAM and 155 LABC from 8 institutions (2016-2022), and 632 M1 from a single institution. The median age was similar between groups (CAM=59 years, LABC=58, M1=57, p=0.44), and there were no statistically significant differences in hormone receptor status (p=0.25). There were more Non-Hispanic Black patients in the M1 cohort compared to CAM or LABC (p&amp;lt; 0.001). The majority of CAM cases were delayed metachronous from the index cancer (type 2, 35.1%), or synchronous with a recurrence (type 3, 33.3%). Type 1 (de novo, 14%) and type 4 (delayed metachronous after breast cancer recurrence, 17.5%) were less frequent. Among CAM patients, 49.1% were hormone receptor positive (HR+)/HER2-negative (HER2-), 22.8% HR-/HER2-, 10.5% HR+/HER2+, and 5.3% HR-/HER2+. Comparing CAM versus LABC, invasive ductal carcinoma (IDC) was more commonly seen in CAM (82.5% vs 66.5%), as was grade 3 (45.6% vs 35.5%), and triple negative (22.8% vs 13.5%). Conversely, in LABC, treatment of the primary index cancer more frequently included chemotherapy (CAM=71.9%, LABC=92.3%), mastectomy (CAM=54.4%, LABC 74.2%), and adjuvant radiation (CAM=73.7%, LABC=90.3%). On multivariable analysis adjusting for age, race/ethnicity, and hormone receptor status, both CAM and M1 had inferior survival to LABC (Table 1), but with a 2.4-fold difference for CAM (95% CI 1.42-4.07, p=0.001) versus a 6.3-fold difference for M1 (95% CI 4.29-9.23, p=&amp;lt; 0.001). Discussion In this contemporary, multi-institution study, we demonstrated that CAM patients selected for presumed curative intent treatment experienced improved OS when compared to stage IV (M1) patients. Our data adds additional support for re-evaluating the current stage IV designation, in favor of N3, and consideration of curative intent treatment in this disease. Table. Adjusted* Overall Survival Comparing Patients with Breast Cancer Contralateral Axillary Metastasis (CAM) to those with Locally Advanced Breast Cancer (LABC) and Metastatic Disease (M1) *Adjusted for age, race/ethnicity, hormone receptors. Citation Format: Meghan R. Flanagan, Stephanie Downs-Canner, Samantha Thomas, Astrid Botty van de bruele, Margaret Lillie, Kristalyn Gallagher, Tammeza Gibson, James Jakub, Alexandra Verosky, Sarah Tevis, Malia Brennan, Francys Verdial, Jennifer Q. Zhang, Leisha Elmore, Jennifer Plichta, Laura Rosenberger. A Multi-Institutional Review of Contralateral Axillary Metastases: Time for Reclassification as Local-Regional Event? [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-05-13.

Abstract PO1-22-10: Long term outcomes of breast cancer patients with local recurrence after mastectomy undergoing immediate breast reconstruction: A retrospective multi-institutional study of 4153 cases

Abstract Background: The number of breast cancer patients in Japan undergoing immediate breast reconstruction (IBR) has increased and the postoperative follow-up period has been extended. This study was conducted to clarify the clinical aspects of and factors associated with local recurrence (LR) after IBR. Methods: This was a multicenter study which included 4153 early breast cancer patients who underwent IBR. Clinicopathological characteristics were examined and factors potentially contributing to LR were analyzed. Risk factors for LR were examined separately for non-invasive and invasive breast cancers. Results: The median follow-up period was 75 months. The 7-year LR rates were 2.1% and 4.3% for non-invasive and invasive cancers, respectively (p &amp;lt; 0.001). The proportions of LR detected by palpation, subjective symptoms, and ultrasonography were 40.0%, 27.3%, and 25.9%, respectively. Overall, 75.7% of LR were solitary, and 92.7% of these cases had no further recurrences during the observational period. Multivariate analysis of LR for invasive cancer showed that skin-sparing mastectomy (SSM) or nipple-sparing mastectomy (NSM), the presence of lymphovascular invasion, cancer at the surgical margin, and not receiving radiation therapy were factors related to LR. The 7-year overall survival rates of the patients with LR and non-LR of invasive cancers were 92.5% and 97.3%, respectively, (p=0.002). Conclusions: The rate of LR after IBR was acceptably low and IBR can thus be performed safely for early breast cancer patients. Invasive cancer, SSM/NSM, lymphovascular invasion, and/or cancer at the surgical margin should prompt awareness of the possibility of LR. Citation Format: Akiko Ogiya, Naomi Nagura, Ayaka Shimo, Hiroko Nogi, Kazutaka Narui, Hirohito Seki, Hiroki Mori, Shinsuke Sasada, Makoto Ishitobi, Naoto Kondo, Chikako Yamauchi, Kohei Akazawa, Tadahiko Shien. Long term outcomes of breast cancer patients with local recurrence after mastectomy undergoing immediate breast reconstruction: A retrospective multi-institutional study of 4153 cases [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-22-10.