Specimen Margins Research Articles

Impact of indocyanine green on decision making for performing laparoscopic cortical sparing adrenalectomy.

Indocyanine green imaging (ICG) is an expansion technology that can contribute to the development of demanding techniques such as cortical-sparing adrenalectomy (CSA). The aim of this study was to determine in which cases CSA should be performed and when total adrenalectomy should be performed instead based on ICG fluorescence. Here, we present our experience through a series of cases and videos. Prospective and descriptive study on patients with surgical adrenal lesions who were proposed for CSA using ICG with near-infrared fluorescence imaging in our center. A first bolus of 6,25mg ICG was administered intravenously upon exposure of the retroperitoneal plane. Fluorescence was visualized using a Storz® NIR/ICG endoscopic system. Seven patients were proposed for CSA. After the application of ICG, a change in attitude was carried out in 71.4% of the cases (five of seven). In the two patients in whom CSA could be performed, the adrenal remnants were functional, and the resection margins of the surgical specimens were free of disease. The reasons why partial adrenalectomy could not be completed, and a total adrenalectomy was decided instead were the presence of a tumor located very close to the adrenal vein that prevented a correct remnant volume (n = 4) and one case of isofluorescent tumor with the adrenal parenchyma. ICG fluorescence guidance could help in the decision making to select patients intraoperatively for successful cortical preservation.

Cerenkov Luminescence Imaging and Flexible Autoradiography for specimen margin assessment during breast-conserving cancer surgery

Abstract Background Among women with breast cancer who undergo breast-conserving surgery (BCS), 20-25% require further surgery due to close or involved margins. Improved techniques are needed to assess resection margins. Purpose The study aims were to assess the feasibility of the combined techniques of Cerenkov Luminescence Imaging—Flexible AutoRadiography (CLI-FAR) to assess excision specimen margins in women undergoing breast-conserving surgery (BCS) and to determine the diagnostic performance of intraoperative CLI-FAR imaging with postoperative histopathology as the reference standard. Materials and Methods Women undergoing BCS were recruited prospectively at a single centre over thirteen months. Patients were injected with 250MBq +/- 10MBq of 18F-fluorodeoxyglucose (18F-FDG), 145 minutes before surgery and the excised specimens were imaged intraoperatively. The surgically excised tumour was initially imaged using conventional x-ray, and margins suspected to be involved by tumor were then imaged using CLI-FAR. CLI-FAR imaging was performed using the LightPath system® (Lightpoint®), an in vitro diagnostic device designed to identify and locate positron-emitting radionuclides. Any suspicious margin underwent an immediate re-excision in the form of cavity shavings. Sensitivity, specificity, positive and negative predictive value whilst considering histopathological assessment as the golden standard were used to assess the performance of CLI-FAR. Results In all, 54 specimens were imaged in 52 patients with a total of 104 margins reviewed using CLI-FAR. The results showed a specificity of 97.8% (89/91, 95% CI: 95.0%, 100.6%), sensitivity of 76.9% (10/13, 95% CI: 68.3%, 85.0%), positive predictive value (PPV) of 83.3% (10/12, 95% CI: 76.2%, 90.5%) and negative predictive value (NPV) of 96.7% (89/92, 95% CI: 93.3%, 100.2%). In all, 8 patients had 10 positive margins on CLI-FAR imaging and were treated accordingly. CLI-FAR imaging reduced the re-excision rate by (17.3/25) 69%. Conclusion CLI-FAR imaging is a promising technique for intraoperative margin assessment in women undergoing BCS for invasive breast cancer.

Anastomotic Leakage after Colorectal Surgery is Associated with a Specific Tissue-Microbiome Signature

Abstract Background Anastomotic leakage (AL) occurs in 5-15% of colorectal resections. In addition to well-known risk factors, recent evidence suggests that the gut microbiota might critically affect anastomotic healing. However, studies in humans are limited. Aims To explore differences in pre-operative microbiome of patients with or without AL and identify anastomosis-protective or damaging bacterial species. Methods Clinical records of patients undergoing left colon or rectal resection with anastomosis at our department between 2013 and 2021 were screened. AL cases were matched equally to controls by propensity score, based on common AL risk factors. The microbiome was analyzed by amplification and sequencing of the V4 region of the 16S gene of DNA extracted from formalin-fixed paraffin-embedded mucosa taken at the proximal and distal margin of the resected specimen, mixed in equal amounts. Differential abundance of identified operational taxonomic units (OTUs) in AL-cases and controls was tested by using the R-package DESeq2. Results Among 588 patients screened, 41 cases and 42 matched controls were eligible for microbiome analysis. Patient characteristics were similar except for a higher percentage of rectal resections in the AL group. Out of 5406 OTUs identified, 197 OTUs were differentially abundant between the two groups (adjusted-p value <0.05). Of those, 175 OTUs were more prevalent in the AL-group, in particular Fusobacterium periodonticum (32% vs. 5% of patients) and bacteria from the Hyphomicrobium genera (39-44% vs. 12-21%); 22 were more prevalent in the control group, in particular Akkermansia muciniphila (26 vs. 17%) and Eubacterium sireum (19 vs. 5% of patients). Conclusion Our analysis unravels AL-associated microbiome-signatures and identifies bacterial species highly prevalent in particular in patients with AL. These findings could be used for future research to develop targeted antibiotic therapy that helps prevent AL.

Raman spectroscopy for esophageal tumor diagnosis and delineation using machine learning and the portable Raman spectrometer

Esophageal cancer is one of the leading causes of cancer-related deaths worldwide. The identification of residual tumor tissues in the surgical margin of esophageal cancer is essential for the treatment and prognosis of cancer patients. But the current diagnostic methods, either pathological frozen section or paraffin section examination, are laborious, time-consuming, and inconvenient. Raman spectroscopy is a label-free and non-invasive analytical technique that provides molecular information with high specificity. Here, we report the use of a portable Raman system and machine learning algorithms to achieve accurate diagnosis of esophageal tumor tissue in surgically resected specimens. We tested five machine learning-based classification methods, including k-Nearest Neighbors, Adaptive Boosting, Random Forest, Principal Component Analysis-Linear Discriminant Analysis, and Support Vector Machine (SVM). Among them, SVM shows the highest accuracy (88.61 %) in classifying the esophageal tumor and normal tissues. The portable Raman system demonstrates robust measurements with an acceptable focal plane shift of up to 3 mm, which enables large-area Raman mapping on resected tissues. Based on this, we finally achieve successful Raman visualization of tumor boundaries on surgical margin specimens, and the Raman measurement time is less than 5 min. This work provides a robust, convenient, accurate, and cost-effective tool for the diagnosis of esophageal cancer tumors, advancing toward Raman-based clinical intraoperative applications.

Neutrophil-driven and interleukin-36γ-associated ocular surface inflammation in chronic Stevens-Johnson syndrome.

This study aims to elucidate the tear proteome and understand the underlying molecular mechanisms involved in the ocular complications following Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN). Mass spectrometry (MS) was performed to quantify the tear fluid proteins from chronic SJS/TEN patients (n = 22 eyes) and age- and gender-matched controls (n = 22 eyes). The candidate proteins were validated using ELISA (n = 80 eyes) in tear samples and immunohistochemistry (IHC; n = 12) in eyelid margin specimens. These proteins were compared for significant differences based on age, gender, disease duration, and ocular severity. A total of 1692 tear fluid proteins were identified, of which 470 were significantly differentially regulated in chronic SJS/TEN. The top 10 significantly upregulated proteins were neutrophil secretions including neutrophil elastase (p < .0001), defensin (p < .0001), and matrix metalloproteinase 8 (p < .0001). The presence of neutrophils was confirmed by the upregulation of IL-8 (p < .001) in tears, a key cytokine known for recruiting neutrophils. Additionally, positive expression of myeloperoxidase was observed in the keratinized eyelid margins of SJS/TEN to validate the presence of neutrophils. Among 41 unique proteins identified by MS, IL-36γ (p < .01) was expressed in three SJS/TEN patients and was confirmed in SJS/TEN tears and eyelid margins by ELISA and IHC, respectively. IL-36γ was specifically expressed in the superficial layers of eyelid margin keratinized conjunctiva. The majority of the significantly downregulated proteins were lacrimal gland secretions such as lacritin (p < .0001) and opiorphin (p < .002). Neutrophil elastase (p < .02) was significantly elevated in patients with severe eyelid margin keratinization. Our observations indicate a clear correlation between eyelid margin keratinization and the expression of IL-36γ, potentially mediated by neutrophils recruited via IL-8. Future experimental studies are needed to test the role of therapies targeting IL-8 and/or IL-36γ in reducing eyelid margin keratinization and its associated ocular complications in SJS/TEN.

Association of the Specimen and Tumor Bed Margin Status with Local Recurrence and Survival in Open Partial Laryngectomy.

Background/Objectives: Positive margins are associated with locoregional recurrence in early laryngeal cancer. The aim of this study was to evaluate the impacts of specimen-driven (ex vivo) positive margins on patients with early-stage laryngeal cancer whose tumor bed (defect-driven) margins had been negative. Methods: A retrospective study was performed on 60 consecutive T1b/T2 glottic cancer patients who underwent open frontolateral laryngectomy. The intraoperative margins were obtained from the tumor bed. Their recurrence and disease-free survival were evaluated. In all cases, negative margins were obtained from the surgical bed. The impact of positive margins from the specimen was evaluated in a paraffin study. Results: Among 10 patients with positive margins in the specimen, six experienced local relapse, and among 50 patients with negative margins in the specimen, three developed recurrence. The 5-year disease-free survival rates were 37.5% and 93.9%, respectively (p < 0.001; log-rank). Even with negative margins in the surgical bed, patients with positive margins in the specimen at the final histopathological examination had a 3.5-fold higher chance of developing local recurrence than those with negative margins (HR = 13.993; 95% CI: 3.479-56.281; p < 0.001; univariate Cox regression). Conclusions: Specimen-driven positive margins represent a significant risk factor for local recurrence, even under negative margins at the tumor bed.

291 Supra-maximal Extent of Resection is Associated With Improved Progression-Free Survival in Patients With IDH Wild-Type Glioblastoma Once Negative TERT Promoter Molecular Margins are Achieved

INTRODUCTION: The standard of care for isocitrate dehydrogenase (IDH) wild-type GBM involves safe maximal resection with subsequent chemoradiation. TERT promoter (TERTp) mutations are clonal in &gt;85% of IDH wild-type GBMs, detectable in all tumor cells. Advances in surgical management have focused on optimizing maximal resection given the positive correlation between extent of resection (EOR) and post-operative outcomes. METHODS: TERTp mutation detection in margin specimens was performed via a novel 30min qPCR-based method. A machine learning algorithm incorporating preoperative anatomic and intraoperative characteristics was developed using 148 patients to predict EOR. This model was prospectively applied to 44 patients to assess the correlation between a TERTp mutation negative margin and survival in cases when GTR was predicted. RESULTS: Retrospective analysis of 148 patients who underwent resection of GBM revealed significant improvement in 36-month survival with residual volume (RV) &lt;4.9 cc). The primary predictive characteristics for achieving this RV were tumor volume, ventricular contact, multifocality, and Sawaya grade. Prospective analysis of 44 patients showed that, in cases where GTR was predicted and achieved, 26% obtained a TERTp negative margin. Although small, this group's PFS was significantly prolonged (0% vs 75% event-free at 30 months, p = 0.02), and a numerically superior prolonged OS was observed, while survival in GTR with positive molecular margin was indistinguishable from STR. CONCLUSIONS: These findings provide novel evidence supporting the utility of supramaximal resection targeting a “molecular margin” to maximize postoperative survival for a subset of patients with “localized” GBM. Further study is warranted to assess intraoperative, quantitative testing of TERTp mutation in GBM specimens to guide marginal resection in these patients.

Abstract 6434: Microenvironment of adjacent non-neoplastic regions determines prognostic outcomes in locally advanced colorectal cancer after surgical resection: A multi-center &amp; multi-omics study

Abstract Background: There is an unmet need for additive predictive biomarkers for the recurrence of stage II/III colorectal cancer (CRC) after surgery. We hypothesized that the heterogeneities of tumors present a substantial impediment to finding agnostic biomarkers. To avoid this, we focused on the normal tissue from the margins of resected specimens. Methods: We divide the groups using RNA sequencing derived from 273 tumors and 273 paired normal tissues from 5 Korean cancer centers. Groups were defined as follows: tumor-like microenvironment in normal mucosa (tNME): high level of tumor signature in normal mucosa; healthy normal microenvironment (hNME): low tumor signature in normal tissue. The impact of this classification was further evaluated in TCGA cohort. For the mechanistic explanation, we conducted 16s rRNA metagenomics and single-cell RNA sequencing from 47 patients and validated by spatial transcriptomics. Results: There were no significant differences between subgroups in baseline characteristics, including age, sex, medical centers, sidedness, stage and the distance between tumor and paired normal tissue. With a median follow-up of 58.2 months, the tNME group showed poor 5-year recurrence-free survival (54.7 vs. 73.0%, HR=1.94, P=0.002) and 5-year overall survival (OS; 78.2 vs. 83.0%, HR=1.76, P=0.033). In addition, tNME showed a trend toward poorer 5-year OS (34.5% vs. 68.8%, HR=3.76, P=0.071) in TCGA. The pathway analysis exhibited tNME had decreased maintenance of membrane while increased expression of humoral reaction to bacteria. Only the tNME group showed similar microbiome diversity between tumor and normal tissues, consisting of more proportion of carcinogenic genera, including fusobacterium and bacteroides than hNME. scRNA-seq revealed a positive co-occurrence of Th17, GZMKhighCD8+T cells, and IL1Bhigh neutrophils in the tumor and normal tissues of tNME. A high proportion of EMP1high epithelial cells, were observed in the tNME group, with upregulated epithelial-mesenchymal transition (EMT), bacterial-cellular-invasion and leukocyte signaling pathways. The cell-cell interaction analysis suggest Th17 cells promote IL1Bhigh neutrophil retention, increasing crosstalk with CD8+ T cells, and inducing the production of high levels of GZMK, which in turn decreases E-cadherin in the intestinal epithelium. A weak intestinal barrier may provoke more bacteria-infected cancer cells, promoting cancer cell progression via EMT and recruiting IL1Bhigh neutrophils and GZMKhighCD8+T cells, resulting in a vicious cycle. Conclusions: The microenvironmental status of normal tissues offers a promising biomarker for stage II/III CRC. Microbiota dysbiosis-induced organized microniches with immune and epithelial cells was related to metachronous recurrence after surgical resection. Citation Format: Yeong Hak Bang, Ji Hye Choi, Kyunghee Park, Jinyeong Lim, Dae Hee Pyo, Yong Beom Cho, Tae-You Kim, Kyu Joo Park, Seung-Bum Ryoo, Sung-Bum Kang, Chang Sik Yu, Kil-yong Lee, Jaeim Lee, Jin-Young Lee, Young-Joon Kim, Woong-Yang Park. Microenvironment of adjacent non-neoplastic regions determines prognostic outcomes in locally advanced colorectal cancer after surgical resection: A multi-center &amp; multi-omics study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6434.

Comparison of Two Techniques for Proximal Margin Analysis of Toe Amputations: A Retrospective Review

Toe amputations are a common podiatric procedure for treatment of osteomyelitis. Whether or not the surgeon obtains a surgical cure, thus resolving the infection, can be difficult to assess. Obtaining a proximal bone margin can assist the treatment team in deciding the duration of postoperative antibiotics, need for reoperation, and postoperative care. The two senior surgeons use different methods to analyze proximal bone margins. The first surgeon obtains a microbiologic culture from the remaining bone, either at the proximal phalanx or metatarsal head, following the removal of the toe to be reviewed for osteomyelitis. Per the second surgeon's technique, the pathologist only analyzes the proximal aspect of the amputated toe for presence of osteomyelitis. Our goal is to analyze the reoperation and reamputation rates between the techniques in which the proximal margin specimens are obtained. A retrospective chart review was performed on all isolated toe or partial toe amputations from March 2017 to September 2022. There were 115 patients who met inclusion criteria. Reoperation and reamputation rates were analyzed for positive and negative infection margins from intraoperative cultures. Our study found an overall 28% reoperation rate and 26% reamputation rate for the negative margins group. In the positive proximal margin group, there was an overall 48% reoperation rate and 44% reamputation rate. Our analysis did not find a statistically significant difference between the reamputation rate in the negative margins group and the reamputation rate in the positive margins group. In conclusion, our study found that a positive proximal margin for osteomyelitis exhibited a nearly double reoperation and reamputation rate compared to patients with a negative margin, and that one margin analysis technique was not inferior to the other in regards to the need for additional surgeries.

Specimen tomosynthesis provides no additional value to specimen ultrasound in ultrasound-visible malignant breast lesions.

The aim of this study was to evaluate the accuracy and added value of specimen tomosynthesis (ST) to specimen ultrasound (SUS) in margin assessment of excised breast specimens in breast-conserving therapy for non-palpable US-visible breast lesions. Between January 2018 and August 2019, all consecutive patients diagnosed with non-palpable breast cancer visible by ultrasound (US), treated with breast-conserving surgery (BCS) and requiring radiological intraoperative breast specimen assessment, were included in this study. Excised breast specimens were examined with SUS by radiologists blinded to the ST results, and margins smaller than 10 mm were recorded. STs were evaluated retrospectively by experienced radiologists. A total of 120 specimens were included. SUS showed a statistically significant correlation with pathological margin measurements, while ST did not and provided no additional information. The odds ratios (ORs) for SUS to predict a positive margin was 3.429 (confidence interval (CI) = 0.548-21.432) using a 10-mm cut-off point and 14.182 (CI = 2.134-94.254) using a 5-mm cut-off point, while the OR for ST were 2.528 (CI = 0.400-15.994) and 3.188 (CI = 0.318-31.998), respectively. SUS was superior in evaluating intraoperative resection margins of US-visible breast resection specimens when compared to ST. Therefore, ST could be considered redundant in applicable situations.

Residual cervical H-SIL after cervical conization with positive margins. Is there any associated risk factor?

Introduction: Cervical cancer is the second leading cause of death from gynecological cancer. In Argentina, it is estimated that nearly 4,500 new cases are diagnosed each year and 1,800 women die from this disease. The human papillomavirus (HPV) is a necessary but not a major cause to develop this type of cancer and it is responsible for producing both low-grade (L-SIL) and high-grade (H-SIL) squamous intraepithelial lesions (SIL) depending on the viral serotype in addition to other factors specific to the infected patient. Cervical intraepithelial neoplasia (CIN) is treated by local ablation or excision techniques with lower morbidity. The choice of treatment depends on the degree and extent of the disease, as well as the patient age, risk factors and immunity to generate spontaneous regression or persistence/recurrence. Objective: To identify clinical or pathological factors in patients who presented residual lesion (H-SIL) in the surgical specimens of both re-conization and hysterectomy (HT). Materials and methods: A retrospective, observational study was carried out at Sanatorio Güemes, Buenos Aires, Argentina. All patients that underwent cervical conization with an electric scalpel and had positive margins in the surgical specimen between January 2017 and May 2022 inclusive were analyzed. Data was obtained from 43 patients who had positive cervical conization specimen margins at our institution in the time period described above. Two patients who only had the exocervical margin involved and also 11 patients who did not meet the inclusion criteria were excluded. Among patients (30), all were reoperated (16 underwent re-conization, while in 14 patients it was decided to have a total hysterectomy). Among all the patients who underwent a new surgical procedure, residual disease was found in 10 patients (33.3%), while 20 patients (66.6%) had no residual lesion. Results: The highest percentage of patients (66.6%) did not present residual lesions in the posterior resection specimens. The parameter exhibiting the most substantial influence in our analysis was the proportion of lesion extension, exerting a significant effect on the persistence/recurrence of the disease in subsequent surgical samples (Relative Risk [RR] 7.87, 95% Confidence Interval [CI] 1.13-54.66, p &lt; 0.01). Conclusion: This information brings us even closer to the new reports of bibliographical data: although the presence of the compromised endocervical margin is valuable for estimating the risk of disease persistence/recurrence, it is not sufficient. Therefore, there is a lack of information about the importance of other factors to predict this situation.

Prognostication in Lymph Node-Positive Prostate Cancer with No PSA Persistence After Radical Prostatectomy.

This study aimed to create a prognostic model to predict disease recurrence among patients with lymph node involvement but no prostate-specific antigen (PSA) persistence and to explore its clinical utility. The study analyzed patients with lymph node involvement after pelvic lymph node dissection with radical prostatectomy in whom no PSA persistence was observed between 2006 and 2019 at 33 institutions. Prognostic factors for recurrence-free survival (RFS) were analyzed by the Cox proportional hazards model. Among 231 patients, 127 experienced disease recurrence. The factors prognostic for RFS were PSA level at diagnosis (≥ 20 vs. < 20ng/mL: hazard ratio [HR], 1.66; 95% confidence interval [CI], 1.09-2.52; P = 0.017), International Society of Urological Pathology grade group at radical prostatectomy (RP) specimen (group ≥ 4 vs. ≤ 3: HR, 1.63; 95% CI 1.12-2.37; P = 0.010), pathologic T-stage (pT3b/4 vs. pT2/3a: HR, 1.70; 95% CI 1.20-2.42; P = 0.0031), and surgical margin status (positive vs. negative: HR, 1.60; 95% CI 1.13-2.28; P = 0.0086). The prognostic model using four parameters were associated with RFS and metastasis-free survival. The prognostic model in combination with postoperative PSA value and number of lymph nodes is clinically useful for discussing treatment choice with patients.

P440 Myenteric plexitis and active inflammation at surgical margins are high-risk predictors for postoperative clinical recurrence of Crohn’s disease

Abstract Background Preventing postoperative recurrence is an important issue for clinical management of Crohn’s disease (CD). Identification of practical risk factors and an effective prophylactic treatment strategy has been desired for the prevention of postoperative recurrence. Although some of the clinical risk factors have been applied to select candidates for prophylactic treatments, these attempts have not fully prevented postoperative recurrence. In this study, we investigate the histological features at resected margins which predicted postoperative recurrence, and whether the initiation of prophylactic treatments could prevent postoperative recurrence in these cases. Methods We retrospectively reviewed the clinical recurrence rate in CD patients who underwent intestinal resection between January 2019 and December 2021. Clinical recurrence was defined by combination of serological, radiographic, and endoscopic findings or treatment escalation. To assess the histological risk factors for postoperative recurrence, resection margins of the surgical specimens were evaluated for the presence of myenteric plexitis, granulomas, and active inflammation. Each histological feature was evaluated from Grade 0 to 3. We also examined the ability of prophylactic treatments to prevent postoperative recurrence stratified with histological findings related to clinical recurrence rates. Results Of the 141 patients included in this study, 61.9% had plexitis (grade 3:Inflammatory cells at myenteric plexus, 10&amp;gt;HPF) at the proximal margin and 13.5% had active inflammation (grade 3: erosion or ulcer) at the distal margin. Log rank test identified the presence of plexitis (Grade3) (HR:1.84, 95%CI [1.05-3.22], p=0.029) at the proximal margin and active inflammation (Grade3) at the distal margin (HR:1.29, 95%CI [1.05-1.58], p=0.012) as possible risks of clinical recurrence (Figure). Multivariate analysis confirmed that the presence of plexitis (Grade3) at the proximal margin (HR 1.82, 95% CI 1.04-3.21, P=0.038) and active inflammation (Grade 3) at the distal margin (HR 2.31, 95% CI 1.18-4.46, P=0.013) were associated with postoperative clinical recurrence. Prophylactic use of immunomodulators (IM) and biologics did not show a significant reduction of clinical recurrence compared to treatment without IM and/or biologics in patient with histological risk factors (Table). Conclusion Our results indicate that the presence of plexitis in the proximal margin and active inflammation in the distal margin of the resected intestine are risk factors for postoperative recurrence. In these cases, initiation of prophylactic treatments with biologics and/or IM may not prevent the clinical recurrence.

The radiological morphology of mesopancreas: A new variable to predict a positive vascular margin after pancreatoduodenectomy for pancreatic ductal adenocarcinoma?

615 Background: The most frequently invaded surgical margins on pancreatoduodenectomy (PD) specimens of pancreatic ductal adenocarcinoma (PDAC) are vascular margins, especially the superior mesenteric artery (SMA), also called mesopancreatic margin. Considering embryology, it may be hypothesized that PDAC cells tend to infiltrate the retroperitoneum through the contents of mesopancreas, justifying the frequent SMA positive margin. Because the radiological aspect of mesopancreas has been poorly studied, the aim of this original research was to assess the mesopancreatic infiltration on diagnostic imaging, corroborate with the corresponding margin pathology and evaluate the impact on survival in PDAC patients who underwent PD. Methods: From 2015 to 2021, all patients who underwent PD for PDAC with curative intent were reviewed, excluding patients lost to follow-up, who died postoperatively or within the first year for non-oncological reason, and those with unavailable preoperative imaging. Surgical margins of pathological specimens were reassessed. Blinded reviewing of preoperative radiographic images was conducted. According to qualitative assessment, the mesopancreas tissue was defined as normal fat (NF), fat stranding (FS) or solid infiltration (SI). Results: 133 patients were included in the study, including 51 (38%) who received neoadjuvant therapy. The tumor location was into the head or the uncinate process in 54% and 46%, respectively. At diagnosis, PDAC were classified as resectable (51%), borderline resectable (28%) and locally advanced (9%) according to the NCCN classification. FS or SI in the mesopancreas was present in 45 (34%) and 18 (14%) patients, respectively. Tumor size on imaging, tumor location, chronic obstructive pancreatitis, vascular contacts and NCCN resectability status were predictive factors of mesopancreas infiltration (p&lt;0.001). Median overall and disease-free survivals were significantly lower in case of SI compared to NF and FS in the mesopancreas. When comparing patients with mesopancreatic FS at diagnosis who received neoadjuvant therapy (n=20) to those who underwent upfront surgery (n=25), no significant impact was observed in survivals. R0 resection was obtained in 36%; in all patients with R1 resection, a vascular margin was involved. Tumor size at pathology, SMA margin and resection status were factors that were significantly influenced by the radiological infiltration of the mesopancreas. Conclusions: The SI of mesopancreas on diagnostic imaging was associated with a poor prognosis, but not FS, in patients who underwent PD for PDAC. SMA margin and resection status were correlated with the radiological texture of the mesopancreas, which suggests to further explore underlying mechanisms related to tumoral invasion of vascular margin and mesopancreas.

Ten-year follow-up outcomes of limited resection trial for radiologically less-invasive lung cancer.

The JCOG0804/WJOG4507L single-arm confirmatory trial indicated a satisfactory 10-year prognosis for patients who underwent limited resection for radiologically less-invasive lung cancer. However, only one prospective trial has reported a 10-year prognosis. We conducted a multicenter prospective study coordinated by the National Cancer Center Hospital East and Kanagawa Cancer Center. We analyzed the long-term prognosis of 100 patients who underwent limited resection of a radiologically less-invasive lung cancer in the peripheral lung field. We defined radiologically less-invasive lung cancer as lung adenocarcinoma with a maximum tumor diameter of ≤2cm, tumor disappearance ratio of ≥0.5 and cN0. The primary endpoint was the 10-year local recurrence-free survival. Our patients, with a median age of 62years, included 39 males. A total of 58 patients were non-smokers; 87 had undergone wide wedge resection and 9 underwent segmentectomy. A total of four cases were converted to lobectomy because of the presence of poorly differentiated components in the frozen specimen or insufficient margin with segmentectomy. The median follow-up duration was 120.9months. The 10-year recurrence-free survival and overall survival rates of patients with lung cancer were both 96.0%. Following the 10-year long-term follow-up, two patients experienced recurrences at resection ends after wedge resection. Limited resection imparted a satisfactory prognosis for patients with radiologically less-invasive lung cancer, except two cases of local recurrence >5years after surgery. These findings suggest that patients with this condition who underwent limited resection may require continued follow-up >5years after surgery.

Tumor Bed Margins Versus Specimen Margins in Oral Cavity Cancer: Too Close to Call?

The routine assessment of intraoperative margins has long been the standard of care for oral cavity cancers. However, there is a controversy surrounding the best method for sampling surgical margins. The aim of our study is to determine the precision of a new technique for sampling tumor bed margins (TBMs), to evaluate the impact on survival and the rate of free flap reconstructions. This retrospective cohort study involved 156 patients with primary cancer of the tongue or floor of the mouth who underwent surgery as initial curative treatment. Patients were separated into 2 groups: one using an oriented TBM derived from Mohs' technique, where the margins are taken from the tumor bed and identified with Vicryl sutures on both the specimen and the tumor bed, and the other using a specimen margins (SMs) driven technique, where the margins are taken from the specimen after the initial resection. Clinicopathologic features, including margin status, were compared for both groups and correlated with locoregional control. Precision of per-operative TBM sampling method was obtained. A total of 156 patients were included in the study, of which 80 were in TBM group and 76 were in SM group. Precision analysis showed that the oriented TBM technique pertained a 50% sensitivity, 96.6% specificity, 80% positive predictive value, and an 87.5% negative predictive value. Survival analysis revealed nonstatistically significant differences in both local control (86.88% vs 83.50%; P = .81) as well as local-regional control (82.57% vs 72.32%; P = .21). There was a significant difference in the rate of free flap-surgeries between the 2 groups (30% vs 64.5%; P < .001). Our described oriented TBM technique has demonstrated reduced risk of free flap reconstructive surgery, increased precision, and similar prognostic in terms of local control, locoregional control, and disease-free survival when compared to the SM method.

Abstract A037: Prostate Specific Membrane Antigen Targeted Photodynamic Therapy Agent for the Treatment of Breast Cancer

Abstract Introduction: Breast cancer (BCa) is a solid cancer where 65% of all BCa cases, women with stages 1-3 of BCa undergoing Breast Conserving Surgery (BCS) as the primary form of treatment with incomplete resections occurring in 20-60% of BCS leading to repeat procedures[1]. Local recurrence, an indication of “surgically missed” cancerous tissues, occurs in 5-16% of patients with clean margins [1], indicating regions of tumor not resected during analysis of excised tissues. This demonstrates an unmet clinical need for technologies to identify and destroy cancerous tissues in the margins of BCa specimens. Prostate Specific Membrane Antigen (PSMA) is known to be overexpressed in prostate cancer and on the neovasculature of many solid human tumors, including breast tumors [2]. Photodynamic therapy (PDT) is a minimally invasive phototherapy used in the treatment of cancers and other diseases. Previously, we combined a potent Photodynamic Therapy (PDT) agent and highly selective PSMA ligand invented in our lab, to develop a theranostic agent to selectively identify and destroy prostate cancer (PCa) [3]. We have characterized PSMA expression in BCa tumor neovascualture in our novel syngeneic mouse model and show how PSMA-1-Pc413 is an effective strategy in visualizing and treating BCa tumors. Methods: 20 female BALB/c mice were inoculated with 10,000 4T1 – i.e., metastatic mouse cancer cell line – via injection into the mammary pads to create a syngeneic mouse model. We allowed the tumors to grow till an average of 50mm3. Mice were randomly separated into 3 treatment groups based on PSMA-1-Pc413 and PDT irradiation dose, a combination of 0.75mg/kg or 1.0mg/kg at 100Jcm−2 or 150Jcm−2. A 4th control group that received PBS irradiated with 150jcm−2 of light. PSMA-1-Pc413 was injected via tail vein and fluorescence images were taken till 24hr. 24hours post-injection, we irradiated the tumors at the given dose with a 672 nm laser. Tumor growth was tracked via calipers. The endpoint was 28days after treatment. Mice were euthanized, and their lung nodules quantified through counting. Results: Fluorescence images of a representative mouse from the group show positive accumulation of probe within the tumor which was subsequently bleached after PDT treatment, signified by a dark area. Compared to our control group, we see a significant reduction in tumor growth rate with all 5 mice in each of the treatment groups surviving longer than the control group. Groups that received a higher dose of agent and irradiation showed further improved response. Additionally, after euthanizing animals 4 weeks after PDT treatment and quantifying lung nodules we can see a significant decrease in lung metastases which contributes to improved survival outcomes. Conclusions: From the results provided that PSMA can be used as an in vivo target for treating Breast Cancer and that our PSMA-1-Pc413 agent is effective in non-prostatic cancer models. Even a single dose of PDT with our agent has significant impact in reducing tumor growth rate and lung metastases formation. Citation Format: Aditi A Shirke, Xinning Wang, James P Basilion. Prostate Specific Membrane Antigen Targeted Photodynamic Therapy Agent for the Treatment of Breast Cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2023 Oct 1-4; Toronto, Ontario, Canada. Philadelphia (PA): AACR; Cancer Immunol Res 2023;11(12 Suppl):Abstract nr A037.

Apoptotic Marker Expression of Resected Lacrimal Gland Adenoid Cystic Carcinoma Tumor Margins After Intra-arterial Chemotherapy and Globe-Sparing Excision.

Lacrimal gland adenoid cystic carcinoma (LGACC) is a rare orbital malignancy with devastating lethality. Neoadjuvant intra-arterial chemotherapy (IACC) has demonstrated cytoreductive effects on LGACC macroscopically, but limited studies have examined cellular and molecular determinants of the cytoreductive effect. This post hoc study assessed apoptotic marker expression on excised tumor specimens after neoadjuvant IACC and globe-sparing resection, emphasizing the examination of tumor margins. This retrospective study identified LGACC specimens resected in a globe-sparing technique after neoadjuvant IACC by reviewing the Florida Lions Ocular Pathology database at Bascom Palmer Eye Institute. Histopathology slides of the specimens were re-examined to confirm the diagnosis and identify the tumor margin. Immunofluorescent staining was performed for apoptotic markers, including P53, cleaved caspase-3, cleaved PARP-1, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). Positive expression was determined by comparison to the negative control. Tumor specimens from 5 patients met inclusion criteria. All 5 cases were positive at the center and the margin for TUNEL, p53, and cleaved caspase-3. One case did not show positive expression of cleaved PARP-1 at the margin but was positive for the other apoptotic markers. This post hoc study demonstrated positive staining for multiple apoptotic markers in post-IACC tumor specimens at the tumor center and margin. Apoptotic marker expression along the margins of post-treatment specimens is important, as it may offer surrogate information to speculate on the state of residual cancer cells adjacent to the excision margin inadvertently remaining in the orbit.

SURG-04. FAST DETECTION OF GLIOMA INFILTRATION USING LABEL-FREE OPTICAL MICROSCOPY AND DEEP NEURAL NETWORKS

Abstract INTRODUCTION Fast and accurate detection of tumor infiltration is a central challenge in the comprehensive management of diffuse glioma patients. Despite our best real-time tumor detection strategies, such as intraoperative MRI and fluorescence-guided surgery, dense and safely resectable tumor infiltration remains at the surgical margin in over 85% of diffuse glioma patients. Patterns of treatment failure demonstrate that glioma recurrence occurs at the surgical margin in the majority of patients due to residual tumor burden. Objective Here, we present FastGlioma, an artificial intelligence (AI)-based intraoperative diagnostic system for fast (&amp;lt; 10 seconds) detection of diffuse glioma infiltration at microscopic resolution without the need for tumor-specific markers. Method FastGlioma is trained using large-scale, self-supervised visual feature learning on stimulated Raman histology (SRH), a rapid, label-free, optical microscopy technique, and a GPT-style whole slide SRH tumor infiltration scoring method. We pushed the performance limits of FastGlioma by investigating the trade-off between imaging speed versus accuracy for microscopic tumor detection. RESULTS In a large prospective external testing cohort of diffuse glioma patients (180 patients, 935 surgical margin specimens) who underwent intraoperative SRH imaging, we demonstrate that FastGlioma was able to detect and quantify microscopic tumor infiltration with an average AUROC of 92.1 +/- 0.0%, performing on par with three expert neuropathologists on the same task. FastGlioma is over 10X faster than previous SRH-based methods and 100X faster than conventional H&amp;E histology. Finally, we demonstrate that FastGlioma was &amp;gt; 20% more accurate at detecting dense tumor infiltration when compared to radiologic features or 5-aminolevulinic fluorescence (98.0% versus 77.8% accuracy) for both IDH-mutant diffuse gliomas and IDH-wildtype glioblastomas. CONCLUSION Our results demonstrate how intraoperative optical imaging and deep neural networks can achieve fast and accurate tumor detection, unlocking the role of AI in improving the surgical management of brain tumor patients.

Treatment of rectosigmoid endometriosis by laparoscopic reverse submucosal dissection (LRSD): TheSydney partial thickness discoid excision technique.

Laparoscopic reverse submucosal dissection (LRSD) is a standardised surgical technique for removal of rectosigmoid endometriosis which optimises the anatomical dissection plane for excision of endometriotic nodules. This cohort study assesses the outcomes of the first cohort of women treated by LRSD, for deeply infiltrating rectosigmoid endometriosis. Primary outcomes assessed were complication rate as defined by the Clavien-Dindo system, and completion of the planned LRSD. Secondary outcomes include mucosal breach, specimen margin involvement, length of hospital admission, and a comparison of pre-operative and post-operative pain, bowel function and quality of life surveys. These included the Endometriosis Health Profile Questionnaire (EHP-30), the Knowles-Eccersley-Scott Symptom Questionnaire (KESS) and the Wexner scale. Of 19 patients treated, one required a segmental resection. The median length of hospital admission was two days (range 1-5) and no post-operative complications occurred. Median pain visual analogue scales (scale 0-10) were higher prior to surgery (dysmenorrhoea 9.0, dyspareunia 7.5, dyschezia 9.0, pelvic pain 6.0) compared to post-surgical median scores (dysmenorrhoea 5.0, dyspareunia 4.0, dyschezia 2.0, pelvic pain 4.0) at a median of six months (range 4-32). Quality of life studies suggested improvement following surgery with pre-operative median EHP-30 and KESS scores (EHP-30: 85 (5-106), KESS score 9 (0-20)) higher than post-operative scores (EHP-30: 48.5 (0-80), KESS score: 3 (0-19)). This series highlights the feasibility of LRSD with low associated morbidity as a progression of partial thickness discoid excision (rectal shaving) for the treatment of rectosigmoid deep infiltrating endometriosis.