Curative-intent Surgical Resection Research Articles

Interaction of BRCA1 vs BRCA2 pathogenic variants with primary tumor location in pancreatic cancer.

e16326 Background: BRCA1/2 germline or somatic pathogenic variants (PVs) are found in 5-10% of pancreatic adenocarcinoma (PDAC) patients. Recent data suggest that BRCA2 PVs may be associated with increased overall survival (OS) compared to BRCA1 PVs after adjusting for treatment and clinical characteristics. Additionally, pancreatic tail PDAC was found to harbor PVs in BRCA1/2 more frequently compared to PDAC within the pancreatic head (HOP). We hypothesized that tumor location in patients with BRCA1 and BRCA2 PVs would associate with overall survival and somatic mutation profile. Methods: We conducted a retrospective cohort study using a database of patients with PDAC and BRCA1/2 PVs at an academic center. Demographic and clinical data were compared by Fisher’s exact test. OS was measured using date of death or last follow-up and compared by Cox proportional hazards regression adjusting for treatment with platinum-based chemotherapy and curative-intent surgical resection. Cases with available next generation somatic sequencing were reviewed. Results: There were no significant differences in age, sex, stage at diagnosis, ECOG status at diagnosis, tumor location, treatments, or sites of metastasis between patients with BRCA1 vs BRCA2 PVs. In the overall cohort, we observed no significant difference in OS between patients with BRCA1 vs BRCA2 (17.0 vs 20.2 months). However, survival analysis stratified by tumor location demonstrated that BRCA1 patients with HOP tumors had significantly worse OS compared to BRCA2 patients with HOP tumors (13.1 vs 25.7 months, p = 0.014) and had a significantly higher rate of TP53 mutations (100% vs 50%, p = 0.032). No significant differences in OS or rates of TP53 mutations were observed in the body/tail of the pancreas. Conclusions: These results suggest that there may be differences in rates of somatic variants between BRCA1- and BRCA2-related HOP PDAC and suggest an interaction between BRCA1/2 tumor biology and anatomical location. [Table: see text]

Long-term prognosis of patients with gallbladder carcinoma after curative-intent resection based on changes in the ratio of carbohydrate antigen 19-9 to total bilirubin (CA19-9/TB): a multicenter retrospective cohort study.

The prognostic value of carbohydrate antigen 19-9 (CA19-9) is known to be affected by elevated bilirubin levels in patients with gallbladder carcinoma (GBC). The clinical significance of changes in the ratio of CA19-9 levels to total bilirubin (TB) levels in patients with GBC after curative-intent resection remains unknown. The aim of this study was to determine the prognostic value of changes in preoperative and postoperative CA19-9/TB ratio in these patients. Prospectively colleced data on consecutive patients who underwent curative-intent resection for GBC between January 2015 and December 2020 stored in a multicenter database from 10 hospitals were analysed in this retrospective cohort study. Based on the adjusted CA19-9 defined as the ratio of CA19-9 to TB, and using 2×103 U/µmol as the upper normal value, patients were divided into a normal group (with normal preoperative and postoperative adjusted CA19-9), a normalization group (with abnormal preoperative but normal postoperative adjusted CA19-9), and a non-normalization group (with abnormal postoperative adjusted CA19-9). The primary outcomes were overall survival (OS) and recurrence-free survival (RFS). The log-rank test was used to compare OS and RFS among the groups. The Cox regression model was used to determine factors independently associated with OS and RFS. The normal group (n=179 patients) and the normalization group (n=73 patients) had better OS and RFS than the non-normalization group (n=65 patients) (the 3-year OS rates 72.0%, 58.4% and 24.2%, respectively; the RFS rates 54.5%, 25.5% and 11.8%, respectively; both P<0.001). There were no significant differences between the normal and the normalization groups in OS and RFS (OS, P=0.255; RFS, P=0.130). Cox regression analysis confirmed that the non-normalization group was independently associated with worse OS and RFS. Subgroup analysis revealed that the non-normalization group of patients who received adjuvant therapy had significantly improved OS and RFS as compared to those who did not receive adjuvant therapy (OS, P=0.025; RFS, P=0.003). Patients with GBC who underwent curative-intent surgical resection with postoperative abnormal levels of adjusted CA19-9 (the CA19-9/TB ratio) were associated with poorer long-term survival outcomes. Adjuvant therapy after surgery improved the long-term outcomes of these patients.

Association of human interpretable features derived from pancreatic ductal adenocarcinoma pathology slides with disease-free survival.

e16368 Background: Pancreatic ductal adenocarcinoma (PDAC) is predicted to be the second cause of cancer death in the US by 2040. For the minority of patients who are candidates for curative-intent surgical resection, a neoadjuvant approach with chemotherapy or chemotherapy followed by chemoradiotherapy (chemoRT) has become the standard of care. The tumor microenvironment (TME) has been recognized as a key factor in therapeutic resistance and disease progression. This study aims to explore the prognostic value of human-interpretable machine learning image features (HIFs) derived from whole-slide H&amp;E images. Methods: Consecutive PDAC patients who underwent neoadjuvant therapy followed by surgical resection were studied in this single-institution retrospective study. Clinical variables collected include tumor site (head/body/tail), surgery extent, histology, sex, age at diagnosis, grade, treatment response (4-point scale), LVI, PNI, resection margin status, pathological TNM staging, number of lymph nodes removed/positive, neoadjuvant strategy (chemotherapy vs chemoRT), and number of neoadjuvant chemo cycles. These factors were analyzed with a multivariable Cox proportional hazards model for disease-free survival (DFS) after surgery. Additionally, 420 human-interpretable image features (HIFs) derived from a commercial machine learning software were analyzed with a univariable Cox model on a binary outcome of 1-yr DFS, applying a Bonferroni correction for multiple comparisons to identify significant predictors. Results: Increased neoadjuvant chemotherapy cycles (HR = 0.62, p = 0.001, [median: 8, IQR: 6-12]) and receipt of combination neoadjuvant therapy (HR = 0.15, p = 0.020, [29% chemo, 71% +chemoRT]) exhibited a protective effect in the multivariable DFS model. 3 HIFs quantifying immune cells and macrophages within the cancerous tissue and its stroma were associated with an improved probability of 1-year DFS. Conclusions: In addition to clinical factors, HIFs may offer valuable insights into the tumor microenvironment's influence on PDAC progression, paving the way for improved prognostic models and therapeutic strategies. Future work will integrate clinical predictors with HIFs in a combined model.

Abstract PO3-19-06: MRD Assay evaluates Recurrence and response via a tumor Informed Assessment: MARIA-Breast Observational Trial

Abstract Background: Detectable ctDNA in patients with solid tumors has been associated with disease prognosis pre-treatment, assessing response to therapy in the form of minimal residual disease (MRD), and monitoring for recurrence after curative intent treatment. Utilizing patient-specific genomic mutation profiling of an individual’s cancer from a tissue sample, in conjunction with the patient’s germline DNA, to create a personalized sequencing panel to analyze for a subset of these genetic mutations from ctDNA in blood is a strategy that has high sensitivity for detecting MRD. Studies have shown that pretreatment levels of ctDNA using this approach are a potential early indicator of disease recurrence after surgery, that ctDNA clearance may be an early predictor of favorable outcomes and has been shown to correlate with pathologic complete response (Forde et al. N Engl J Med. 2022, PMID:35403841), and that this approach has high sensitivity for detecting recurrence for patients in advance of the current standard of care (Abbosh et al. Cancer Res (2020) 80 (16_Supplement): CT023). Methods: This is a multi-site, prospective, observational trial in the United States of 200 patients with early stage breast cancer using a patient-specific tumor-informed MRD assay for ctDNA analysis. Participants are asked to provide study specimens prior to initial treatment intervention, after curative intent surgical resection, during adjuvant therapy (as applicable) and pre-recurrence follow-up. ctDNA will be analyzed with an NGS-based, tumor-informed MRD assay that identifies somatic mutations from DNA obtained from the patient’s tumor tissue, subtracts germline variants via NGS-based analysis of the patient’s germline DNA, and detects a selected set of between 18-50 tumor-specific ctDNA in their blood. All primary tumor specimens will undergo full exome sequencing using the Personalized Cancer Monitoring (PCM) assay. Impact of results of this CLIA-approved MRD assay on clinical decision making will be captured. The primary objective is to assess the ability of MRD to predict post-treatment recurrence. Further objectives are to correlate MRD status with pathologic complete response, determine the lead time to detection of recurrence compared to standard of care, and the association of MRD status with overall survival. Active enrollment started in March, 2022. Support: Invitae. Clinical trial information: NCT05219734. Citation Format: Edward Esplin, Kelli Swan, Lee Ifhar, Brandie Heald, Sarah Nielsen, Daniel Pineda-Alvarez, William O'Callaghan, Robert Daber, Darrel Ross, Carlos Vieira, Aadel Chaudhuri, W. Korn. MRD Assay evaluates Recurrence and response via a tumor Informed Assessment: MARIA-Breast Observational Trial [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 PO3-19-06.

Natural history of undifferentiated pleomorphic sarcoma: Experience from the US Sarcoma Collaborative.

Undifferentiated pleomorphic sarcoma (UPS) is a relatively rare but aggressive neoplasm. We sought to utilize a multi-institutional US cohort of sarcoma patients to examine predictors of survival and recurrence patterns after resection of UPS. From 2000 to 2016, patients with primary UPS undergoing curative-intent surgical resection at sevenacademic institutions were retrospectively reviewed. Epidemiologic and clinicopathologic factors were reviewed by site of origin. Overall survival (OS), recurrence-free survival (RFS), time-to-locoregional (TTLR),time-to-distant recurrence (TTDR), and patterns of recurrence were analyzed. Of the 534 UPS patients identified, 53% were female, with a median age of 60 and median tumor size of 8.5 cm. The median OS, RFS, TTLR, and TTDR for the entire cohort were 109, 49, 86, and 46 months, respectively. There were no differences in these survival outcomes between extremity and truncal UPS. Compared with truncal, extremity UPS were more commonly amenable to R0 resection (87% vs. 75%, p = 0.017) and less commonly associated with lymph node metastasis (1% vs. 6%, p = 0.031). R0 resection and radiation treatment, but not site of origin (extremity vs. trunk) were independent predictors of OS and RFS. TTLRrecurrence was shorter for UPS resected with a positive margin and for tumors not treated with radiation. For patients with resected extremity and truncal UPS, tumor size >5 cm and positive resection margin are associated with worse survival OS and RFS, irrespectively the site of origin. R0 surgical resection and radiation treatment may help improve these survival outcomes.

Abstract B026: Dissecting the pancreatic cancer microenvironment using landscape ecology

Abstract Pancreatic ductal adenocarcinoma (PDAC) is predicted to be the second cause of cancer death in the US by 2040. Five-year overall survival is only ~12% despite decades of research. The mainstay of treatment remains chemotherapy in the absence of highly recurrent, therapeutically actionable, genetic targets. For the minority of patients (~15-20%) who are candidates for curative-intent surgical resection, six months of intensive neoadjuvant chemotherapy with/without chemoradiation has become standard-of-care. However, despite evidence of radiographic, metabolic, and biochemical responses, significant viable residual disease on pathologic analysis is almost universally observed with approximately 40-60% risk of disease recurrence. Thus, there is a critical need to better understand why PDAC remains recalcitrant to current therapeutic modalities. Pathologic evaluation of PDAC reveals a complex microenvironment consisting of neoplastic cells dynamically interacting with both “normal” cellular (e.g. mesenchymal, immune) and non-cellular (e.g. collagen) stromal elements. While biologically important, experimental models and small-scale efforts to dissect the PDAC ecosystem are limited by focus on individual tumor compartments and generation of conflicting results. Consequently, there is a need for a more comprehensive understanding of the structure and dynamics of the PDAC TME through the theoretical lens of evolutionary ecology. Current therapies are not focused on the PDAC ecosystem. We hypothesize that cell-cell interactions of PDAC cells with its local niche are important for conferring treatment resistance. Thus, better understanding of said interactions could yield novel ecologically-informed therapies. Consequently, we developed a digital pathology library of approximately 1000 PDAC resection cases (whole-slide H&amp;E images) performed at Mayo Clinic between 2013-2021. Approximately 400 cases are treatment naive while about 600 were treated with neoadjuvant therapy. While some qualitative features of pathologic analysis have prognostic value (e.g., pathologic treatment response, presence of perineural or lymphovascular invasion, extent of desmoplasia), we aim to identify prognostic spatial relationships using tools from landscape ecology. We utilized the HoVer-Net model for nuclei segmentation and classification and spatial statistics methods and landscape fragmentation analysis to understand the spatial organization within the PDAC tumor ecology. With these methodologies, we can assess the spatial context of cell interactions, habitat/niche/microenvironment formation, ecological relationships between cell populations, and the different tissue components. The different spatial statistics/metrics are used to quantify levels of immune cell infiltration, mixing, as well as the complexity and diversity of microenvironment phenotypes leading to high levels of tumor heterogeneity. Such measurements can help predict the likelihood of a PDAC tumor adaptive potential that could lead to fast evolutionary responses to therapy, progression, and poor prognosis. Citation Format: Merih D. Toruner, Luis Cisneros, Zafar Siddiqui, Chady Meroueh, Ritambhara Singh, Carlo Maley, Martin E. Fernandez-Zapico, Ryan M. Carr. Dissecting the pancreatic cancer microenvironment using landscape ecology [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Translating Cancer Evolution and Data Science: The Next Frontier; 2023 Dec 3-6; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_2):Abstract nr B026.

Utility of circulating tumor DNA (ctDNA) for the detection of minimal residual disease (MRD) after curative-intent therapy for patients with localized pancreatic adenocarcinoma (PDAC): A single institution series and meta-analysis.

695 Background: PDAC is associated with a high recurrence rate even after curative-intent surgical resection and perioperative chemotherapy. Detection of MRD in this setting can inform prognosis and may be actionable for innovative targeted therapies or additional chemotherapy to improve outcomes. While CA19-9 may detect disease before it is clinically apparent, it lacks specificity and up to 20% of patients (pts) are non-producers. ctDNA has been shown to be useful for MRD detection in other cancers but its utility in PDAC is not established. Methods: Pts with PDAC who had a commercial ctDNA assay (Natera) after completion of all curative-intent therapy (surgery and chemotherapy) in the MRD setting were included. Recurrence and survival data were correlated with the end-of-treatment (EOT) ctDNA result. Published literature and abstracts for studies examining ctDNA for MRD detection in PDAC using the same testing platform were identified. Available data were pooled to determine EOT ctDNA positivity rate, positive and negative predictive values (PPV, NPV), and lead time from a positive ctDNA to documented recurrence. Results: A total of 33 pts had EOT ctDNA samples collected at our institution. At EOT, ctDNA was + in 30.3% (n = 10). At a median follow-up time of 14.3 months, median recurrence free survival (RFS) for + vs negative ctDNA was 3.6 vs 25.1 months (HR = 15.8 [4.7-53.4], p &lt; 0.001). Correlation of +ctDNA with recurrence showed a sensitivity of 52% (10/19), specificity of 100% (14/14), PPV of 100% (10/10) and NPV of 61% (14/23). Our institutional data were then combined with 138 pts reported in 3 prior publications/abstracts, for a total of 171 pts. Median follow-up ranged from 11.9-14.3 months and the overall EOT+ rate was 39% in the pooled cohort. The pooled sensitivity was 67% (49/73), specificity was 83% (81/98), PPV was 74% (49/66) and NPV was 77% (81/105). In each study as well as the pooled analysis, an EOT+ ctDNA was associated with significantly shorter RFS (HR = 8.1-120.5). Among 10 pts at our institution with recurrence, a + ctDNA test was detected after the recurrence 90% of the time, with a median lag-time of 4.70 months after recurrence (range -2.2 to 16.67 months). In the pooled cohort, among the 73 pts with recurrences, the ctDNA test was + before, at the time of, or after the recurrence in 23 (32%), 9 (12%) and 17 (23%) pts respectively; the ctDNA was negative despite recurrence in the remaining 24 (33%) pts. Conclusions: A tumor-informed positive ctDNA test after EOT shows high specificity and PPV for recurrence and is associated with significantly worse RFS in the MRD setting, while sensitivity of the test remains low. When positive, ctDNA assessment provides an opportunity for innovative therapies in the adjuvant setting to improve outcomes for localized PDAC.

Single cell transcriptomic profiling of appendiceal adenocarcinoma to identify rare tumor cells and a myeloid-enriched tumor microenvironment (TME).

760 Background: Appendiceal adenocarcinoma (AA) is a rare malignancy with distinct clinical and molecular characteristics compared to colorectal cancer (CRC). Currently there is little knowledge regarding how tumor cells from AA interact with the tumor microenvironment (TME). In this study, we performed single cell RNA sequencing (scRNAseq) on metastatic AA tumors taken from three patients undergoing curative intent surgical resection. Methods: After obtaining informed consent, tumor tissue from three patients with AA and one patient with CRC undergoing cytoreductive surgery at the MD Anderson Cancer Center (MDACC) was harvested and dissociated into single cell suspension for scRNAseq; libraries were prepared with ‘5 sequencing (10X Genomics). Bulk RNA sequencing from 19 additional patients with AA was available as a validation cohort. Results: scRNAseq analysis of a cohort of 3 patients with AA, 1 with CRC, and 12 healthy control samples identified 39,451 evaluable single cells after filtering and doublet removal. Separating cells into immune, stromal, and epithelial compartments identified that epithelial cells are rare in AA tumors. On average, AA constituted 62% stroma, 36% immune and only 2% epithelial cells, in contrast to healthy appendix (46% immune, 29% epithelial, 25% stroma). Sub-classification of immune cells revealed enrichment of myeloid cells in AA tumors (67% myeloid, 27% T, 5% B and 1% plasma B cells). This is in contrast to healthy appendix tissue (44% T, 26% plasma B, 22% B, 6% myeloid and 2% mast cells). In CRC, the majority of immune cells from the CRC sample were T cells (69%). These single cell data were used to improve deconvolution of bulk RNAseq, allowing for evaluation of TME contribution to transcription using bulk RNAseq data. Analysis of tumors from 19 patients with AA confirmed myeloid predominance in AA tumors. We performed pseudobulk differential expression analysis between compartments comparing CRC and AA which identified significant differences between compartments. Gene set enrichment analysis enabled identification of organized compartment specific changes. Conclusions: Findings from this study provide new insights into AA's biological distinctions from CRC and represent a crucial step toward better understanding this rare malignancy. Myeloid cells need further investigation in AA to develop specialized management approaches and improve patient outcomes.

Diffuse-Type Histology Is Prognostic for All Siewert Types of Gastroesophageal Adenocarcinoma.

The optimal treatment for gastroesophageal junction adenocarcinoma (GEJA) remains controversial. We evaluated the treatment patterns and outcomes of patients with locally advanced GEJA according to the histological type. We conducted a single-institution retrospective cohort study of patients with locally advanced GEJA who underwent curative-intent surgical resection between 2010 and 2020. Perioperative therapies as well as clinicopathologic, surgical, and survival data were collected. The results of endoscopy and histopathological examinations were assessed for Siewert and Lauren classifications. Among the 58 patients included in this study, 44 (76%) were clinical stage III, and all received neoadjuvant therapy (72% chemoradiation, 41% chemotherapy, 14% both chemoradiation and chemotherapy). Tumor locations were evenly distributed by Siewert Classification (33% Siewert-I, 40% Siewert-II, and 28% Siewert-III). Esophagogastrectomy (EG) was performed for 47 (81%) patients and total gastrectomy (TG) for 11 (19%) patients. All TG patients received D2 lymphadenectomy compared to 10 (21%) EG patients. Histopathological examination showed the presence of 64% intestinal-type and 36% diffuse-type histology. The frequencies of diffuse-type histology were similar among Siewert groups (37% Siewert-I, 36% Siewert-II, and 33% Siewert-III). Regardless of Siewert type and compared to intestinal-type, diffuse histology was associated with increased intraabdominal recurrence rates (P=0.03) and decreased overall survival (hazard ratio, 2.33; P=0.02). With a median follow-up of 31.2 months, 29 (50%) patients had a recurrence, and the median overall survival was 50.5 months. Present in equal proportions among Siewert types of esophageal and gastric cancer, a diffuse-type histology was associated with high intraabdominal recurrence rates and poor survival. Histopathological evaluation should be considered in addition to anatomic location in the determination of multimodal GEJA treatment strategies.

Hepatic arterial oxaliplatin plus intravenous 5-fluorouracil and cetuximab for first-line treatment of colorectal liver metastases: A multicenter phase II trial

BackgroundThe efficacy and tolerability of hepatic arterial infusion (HAI) oxaliplatin plus systemic 5-fluorouracil and cetuximab as frontline treatment in patients with colorectal liver metastases (CRLM) are unknown. MethodsIn this multicenter, single-arm phase II study, patients with CRLM not amenable to curative-intent resection or requiring complex/major liver resection, and no prior chemotherapy for metastatic disease, received HAI oxaliplatin and intravenous 5-fluorouracil, leucovorin and cetuximab, every two weeks until disease progression, limiting toxicity or at least 3 months after complete response or curative-intent resection/ablation. The primary endpoint was overall response rate (ORR). Results35 patients, mostly with bilateral (89%), multiple CRLM (>4, 86%; >10, 46%) were enrolled in eight centers. The ORR was 88% (95% CI, 71%−96%) among evaluable patients (n = 32), and 95% (95% CI 70–100%) among the 22 wild-type RAS/BRAF evaluable patients. After a median follow-up of 8.8 years (95% CI, 8.7-not reached), median progression-free survival was 17.9 months (95% CI, 15–23) and median overall survival (OS) was 46.3 months (95% CI, 40.0-not reached). 23 of the 35 patients (66%), including 22 (79%) of the 25 patients with wild-type RAS tumor, underwent curative-intent surgical resection and/or ablation of CRLM. HAI catheter remained patent in 86% of patients, allowing for a median of eight oxaliplatin infusions (range, 1–19). Treatment toxicity was manageable, without toxic death. ConclusionHAI oxaliplatin plus systemic 5-fluorouracil and cetuximab appears highly effective in the frontline treatment of patients with unresectable CRLM and should be investigated further.

Clinical outcome of surgical resection for multifocal T2-T3 hepatocellular carcinoma up to 3 nodules: a comparative analysis with a single nodule.

Although the Barcelona Clinic Liver Cancer staging system seems to underestimate the impact of curative-intent surgical resection for multifocal hepatocellular carcinoma (HCC), recent studies have indicated favorable results for the surgical resection of multiple HCC. This study aimed to assess clinical outcomes and feasibility of surgical resection for multifocal HCC with up to three nodules compared with single tumor cases. Patients who underwent surgical resection for HCC with up to three nodules between 2009 and 2020 were included, and those with the American Joint Committee on Cancer (AJCC) 8th edition, T1 and T4 stages were excluded to reduce differences in disease distribution and severity. Finally, 81 and 52 patients were included in the single and multiple treatment groups, respectively. Short- and long-term outcomes including recurrence-free survival (RFS) and overall survival (OS), were evaluated. All patients were classified as Child-Pugh class A. RFS and OS were not significantly different between the two groups (P=0.176 and P=0.966, respectively). Multivariate analysis revealed that transfusion and intrahepatic metastasis were significantly associated with recurrence (P=0.046 and P=0.005, respectively). Additionally, intrahepatic metastasis was significantly associated with OS (hazard ratio, 1.989; 95% confidence interval, 1.040-3.802; P=0.038). Since there was no significant difference in survival between the single and multiple groups among patients with AJCC 8th stage T2 and T3, surgical resection with curative intent could be considered with acceptable long-term survival for selected patients with multiple HCC of up to three nodules.

Factors Influencing Recurrence in Medial Breast Cancer Tumors After Skin Sparing Mastectomy and Immediate Breast Reconstruction

BackgroundSkin sparing mastectomy (SSM) with immediate breast reconstruction (IBR) has been established as a safe option for curative-intent surgical resection. Prior studies have shown that medial location of the primary tumor is associated with increased risk of local recurrence. The purpose of this study is to determine the factors associated with recurrence and survival in individuals with breast cancers located in the inner quadrants (medial) who underwent SSM with IBR. MethodsA retrospective chart review was done on individuals with medial breast cancer who received SSM with IBR in British Columbia between 1980 and 2012. ResultsOf 136 individuals with medial breast cancer undergoing SSM with IBR, 27.9% experienced local recurrence and 42.6% overall recurrence. Factors associated with recurrence were T-stage (44.8 vs. 22.4% with T2 disease, P = .02), transverse rectus abdominis muscle (TRAM) flap reconstruction (48.3 vs. 29.5%, P = .00395), prior breast surgery (87.9 vs. 63%, P = .002), and prior radiation therapy (74.1 vs. 38.5%, P < .0001). LR was associated with higher mortality (OR 2.78, 95% CI: 1.26-6.09). ConclusionFor patients with medial tumors undergoing SSM with IBR, potential risk factors for recurrence are T-stage, TRAM flap reconstruction, prior breast surgery, and prior radiation therapy. Local recurrence is associated with poor survival.

MRD assay to evaluate recurrence and response via a tumor-informed assessment: MARIA-Breast observational trial.

TPS622 Background: The recognition that cancers release nucleic acids into the peripheral circulation of the patient has enabled a new paradigm for disease detection and surveillance. Detectable ctDNA in patients with solid tumors has been associated with disease prognosis pre-treatment, assessing response to therapy in the form of minimal residual disease (MRD), and monitoring for recurrence after curative intent treatment. Utilizing patient-specific genomic mutation profiling of an individual’s cancer from a tissue sample, in conjunction with the patient’s germline DNA, to create a personalized sequencing panel to then systematically analyze for a subset of these genetic mutations from ctDNA in blood is a strategy that has high sensitivity in detection of MRD. Studies have shown that pretreatment levels of ctDNA using this approach are a potential early indicator of disease recurrence after surgery, that ctDNA clearance may be an early predictor of favorable outcomes and have been shown to correlate with pathologic complete response (Forde et al. N Engl J Med. 2022, PMID:35403841), and that this approach has high sensitivity in its ability to detect recurrence for patients in advance of the current standard of care (Abbosh et al. Cancer Res (2020) 80 (16_Supplement): CT023). Methods: This is a multi-site, prospective, observational trial in the United States of 200 patients with early stage breast cancer undergoing curative intent treatment, who have FFPE tissue available from resection sufficient for a patient-specific bespoke MRD assay who are willing to provide serial whole blood specimens for ctDNA analysis. Participants are asked to provide study specimens prior to initial treatment intervention, after curative intent surgical resection, during adjuvant therapy (as applicable) and pre-recurrence follow-up. ctDNA will be analyzed with an NGS-based, tumor-informed MRD assay that identifies somatic mutations from DNA obtained from the patient’s tumor tissue, subtracts germline variants via NGS-based analysis of the patients germline DNA, and detects a selected set of between 18-50 tumor-specific ctDNA in their blood. All primary tumor specimens will undergo full exome sequencing using the Personalized Cancer Monitoring (PCM) assay. Impact of results of this CLIA-approved MRD assay on clinical decision making will be captured. The primary objective is to assess the ability of MRD to predict post-treatment recurrence. Further objectives are to correlate MRD status with pathologic complete response, determine the lead time to detection of recurrence compared to standard of care, and the association of MRD status with overall survival. Active enrollment started in March, 2022. Clinical trial information: NCT05219734 .

Impact of Medicaid Expansion on the Treatment and Outcomes of Intrahepatic Cholangiocarcinoma

IntroductionThe Affordable Care Act increased insurance coverage for patients residing in states that expanded Medicaid coverage, but its impact on the outcomes of intrahepatic cholangiocarcinoma (ICC) is not clear. Therefore, we examine the impact of Medicaid expansion (ME) on access to treatment and outcomes of ICC. MethodsWe queried the National Cancer Database (NCDB) data for patients with a diagnosis of ICC (2010–2018). Difference-in-difference (DID) analysis was performed to assess the impact of January 2014 ME on curative-intent surgical resection, multimodal therapy, neoadjuvant chemotherapy, 30-day mortality, and overall survival (OS). ResultsOf the 2150 patients included in the study,1574 (73.2%) and 576 (26.8%) patients lived in non-ME and ME states, respectively. On adjusted DID, ME was independently associated with receipt of curative-intent surgical resection (DID coefficient: 0.05, 95% confidence interval [95% CI]: 0.04–0.06, p = 0.002) and multimodal therapy (DID coefficient: 0.08, 95% CI: 0.06–0.10, p = 0.004). In addition, ME was associated with improved OS in ME states (hazard ratio [HR]: 0.73, 95% CI: 0.62–0.87, p = 0.001) but not in non-ME states (HR: 0.95, 95% CI: 0.80–1.12, p = 0.536). ConclusionME status consistently predicted increased utilization of care processes that improved ICC outcomes, including greater rates of curative-intent surgery and multimodal therapy.

Abstract 990: Immune-suppressive tumor microenvironment leads to poor survival following curative intent surgical resection in soft-tissue sarcomas

Abstract Surgical resection of early stage soft-tissue sarcomas (STS) is a potentially curative treatment; however, many STS tumors will recur. Predicting recurrence and survival outcomes for patients with early stage STS remains a challenge. In this study, we identify prognostic biomarkers from clinical and transcriptomic data form a large set of early stage STS. Primary tumor samples from 69 subjects with STS were sequenced using the Tempus xT targeted DNA and whole transcriptome next-generation sequencing platforms. The most common histologies included were liposarcoma (n=22), gastrointestinal stromal tumor (n=19), and leiomyosarcoma (n=12). As expected, high-grade tumors were associated with decreased DFS and OS times while tumor histology was only correlated with OS. Single sample gene set enrichment analysis (ssGSEA) values for seven Hallmark genesets were correlated with both DFS and OS; including pro-tumor survival pathways (p53, Apoptosis, TNF-α via NF-κB), tumor proliferation pathways (MTORC1, MYC Targets, Mitotic Spindle), and UV Response signaling. These pathways are associated with tumor proliferation as well as an immunosuppressive tumor microenvironment (TME). To assess the TME of these tumors we estimated immune cell infiltration using CIBERSORTx. Of the 22 cell types accounted for by CIBERSORTx, only elevated infiltration of M2 Macrophages were associated with poor DFS and OS. To further determine TME activation we assessed the expression of 74 known immune response associated genes. Only PDCD1 (PD-1) was associated with reduced DFS and OS times. Clustering on the nine variables identified here to correlate with both DFS and OS revealed two distinct clusters demonstrating similar histologies. While histologies were similar across clusters, cluster 2 exclusively included high-grade tumors while cluster 1 was made up of 57.4% high-grade tumors. Sub-classifying cluster 1 into low and high-grade subgroups demonstrated a stepped biomarker expression pattern associated with both tumor grade and cluster membership. Using established TME genesets, high-grade tumors demonstrated higher tumor proliferative scores than low-grade tumors, while cluster 2 tumors demonstrated increased tumor associated macrophage signaling. In a multivariable model, cluster membership outperformed tumor grade and histology as the only significant predictor of DFS or OS. Taken together, while tumor grade is a strong predictor of clinical outcomes following surgical resection in STS, immunosuppressive signaling patters may help to identify patients at the highest risk. Citation Format: Nathan David Seligson, Yan W. Asmann, Tariq Almerey, Steven Attia, Sanjay P. Bagaria. Immune-suppressive tumor microenvironment leads to poor survival following curative intent surgical resection in soft-tissue sarcomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 990.

Perineural Invasion of Pancreatic Ductal Adenocarcinoma is Associated with Early Recurrence after Neoadjuvant Therapy Followed by Resection.

Neoadjuvant therapy (NAT) is increasingly utilized in the treatment of pancreatic ductal adenocarcinoma (PDAC). However, there are limited data on risk factors and patterns of recurrence after surgical resection. This study aimed to analyze timing and recurrence patterns of PDAC after NAT followed by curative resection. The medical charts of patients with PDAC treated with NAT followed by curative-intent surgical resection at a single health system from January 1, 2012 to January 1, 2020 were retrospectively reviewed. Early recurrence was defined as recurrence within 12months of surgical resection. 91 patients were included and median follow up was 20.1months. Recurrence occurred in 50 (55%) patients, with median recurrence free survival (RFS) of 11.9months. Overall, 18 (36%) patients had local and 32 (64%) had distant recurrences. Median RFS and overall survival (OS) between local and distant recurrence were similar. Perineural invasion (PNI) and the presence of a T2 + tumor was significantly higher in recurrence group than in no recurrence group. PNI was a significant risk factor for early recurrence. After NAT and surgical resection of PDAC, disease recurrence was common, with distant metastasis being the most common. PNI was significantly higher in the recurrence group.

Promoting Surgical Resection through Future Liver Remnant Hypertrophy.

An inadequate future liver remnant (FLR) can preclude curative-intent surgical resection for patients with primary or secondary hepatic malignancies. For patients with normal baseline liver function and without risk factors, an FLR of 20% is needed to maintain postsurgical hepatic function. However, the FLR requirement is higher for patients who are exposed to systemic chemotherapy (FLR, >30%) or have cirrhosis (FLR, >40%). Interventional radiologic and surgical methods to achieve FLR hypertrophy are evolving, including portal vein ligation, portal vein embolization, radiation lobectomy, hepatic venous deprivation, and associating liver partition and portal vein ligation for staged hepatectomy. Each technique offers particular advantages and disadvantages. Knowledge of these procedures can help clinicians to choose the suitable technique for each patient. The authors review the techniques used to develop FLR hypertrophy, focusing on technical considerations, outcomes, and the advantages and disadvantages of each approach. Online supplemental material is available for this article. ©RSNA, 2022.

NEO-GAP: A phase II single-arm prospective feasibility study of neoadjuvant gemcitabine/cisplatin/nab-paclitaxel for resectable high-risk intrahepatic cholangiocarcinoma.

4097 Background: Given a high recurrence rate, surgical resection for localized intrahepatic cholangiocarcinoma (IHCC) is curative in only 30-35% of patients. BILCAP has established a standard of care for adjuvant therapy with monotherapy capecitabine. Gemcitabine, cisplatin and nab-paclitaxel combination chemotherapy (GAP) was associated with a response rate of 45% in biliary cancer and 20% of patients who were previously inoperable underwent margin negative resection. Based on these data, we conducted a neoadjuvant study of GAP for resectable but high-risk IHCC. Methods: A multi-institutional prospective single-arm phase II trial was conducted for patients with resectable high-risk disease, as defined by tumor size &gt; 5cm, multiple tumors, presence of radiographic major vascular invasion, and lymph node involvement. Patients were administered 4 cycles (3 months) of preoperative GAP (gemcitabine 800 mg/m2, cisplatin 25 mg/m2 and nab-paclitaxel 100 mg/m2 on days 1 and 8 of a 21-day cycle) prior to an attempt at curative-intent surgical resection. The primary endpoint was completion of all therapy, including both preoperative chemotherapy and resection. Secondary endpoints were toxicity, radiologic response according to Response Evaluation Criteria in Solid Tumor (RECIST) criteria, RFS, and OS. Thirty evaluable patients provided 73% power to reject a null therapy completion rate of 50%, with a target completion rate of 70% using a one-sided exact test with a Type I error of 0.05. Results: Thirty-seven patients were screened and 30 evaluable patients were enrolled. The trial was sequentially activated at each of the 4 sites from 09/18-02/21 and the final patient was enrolled in 09/21. Median age was 60.5 years and 40% were female. Twenty-three patients (77%, 90% CI: 60.6-88.5%; p = 0.0026) completed all preoperative chemotherapy and underwent surgical resection. Ten patients (33%) experienced grade 3-4 treatment-related adverse events, the most common being neutropenia and diarrhea; 47% required at least one dose reduction. Partial response rate was 23% and disease control rate was 90% (PD: 10%, PR: 23%, SD: 67%). Of the 23 patients who successfully underwent surgical resection, 2 (9%) had minor postoperative complications. Median size of largest tumor was 5.5cm, median number of tumors was 3, and 39% were lymph node positive. Median length of hospital stay was 4 days. There was zero treatment related mortality. Conclusions: This study met its primary endpoint and demonstrated that neoadjuvant gemcitabine/cisplatin/nab-paclitaxel is feasible and safe prior to resection of intrahepatic cholangiocarcinoma and does not adversely impact perioperative outcomes. Continued follow-up for RFS and OS with this treatment strategy is underway and larger validation studies are planned. Clinical trial information: NCT03579771.

Outcomes in patients undergoing curative surgery for gastric cancer by facility type and socioeconomic factors: An analysis of the National Cancer Database (NCDB).

4066 Background: Surgical and medical treatment for resectable gastric cancer is complex, and multidisciplinary team involvement is essential to provide optimal treatment outcomes. However, socioeconomic disparities influence the quality of medical care patients receive. We hypothesized that facility type, median income, insurance type, and location would impact patients' overall survival (OS). Methods: In a retrospective analysis of NCDB data, we identified patients with stage II and III gastric adenocarcinoma who underwent curative-intent surgical resection and chemotherapy between 2004-2018. Demographic and socioeconomic factors were studied, including treatment facility type, median household income, urban/rural residence, and insurance status. Multivariate Cox proportional hazard model was used to evaluate the impact of these variables on overall survival (OS). The Kaplan-Meier method was used to estimate OS. Log-rank test was used to compare the OS between groups. Results: Based on the criteria listed above, 36,318 patients were identified: 76.3% were Caucasian, 14.4% black, 7.2% Asian, and 2.0% other. 56.4% lived in large metropolitan areas (LM), 29.9% in small/medium metropolitan areas (SM), and 14.2% in rural areas (RA). Patients who were treated in academic/research programs had significantly better OS (mOS 40.5 months) compared to integrated-network cancer programs (mOS 34.0 months, HR 0.897, p &lt; 0.0001), comprehensive community cancer programs (mOS 31.0 months, HR 0.89, p &lt; 0.0001), and community cancer programs (mOS 29.5, HR 0.881, p &lt; 0.0001). Patients from LM had better OS compared to those from SM and RA (mOS 39.0, 32.1, 29.9 months respectively, p &lt; 0.0001). Privately insured patients had improved OS compared to Medicare-insured patients (mOS 40.8 vs 29.7 months, HR 0.758, p &lt; 0.0001). Higher annual income (≥ $63,000) was positively associated with improved OS (p &lt; 0.0001). Conclusions: Outcomes for patients with gastric cancer treated with surgery and chemotherapy are strongly influenced by socioeconomic variables, including place of residence, treatment setting, insurance, and income level. We highlight improved outcomes in patients who resided in LM and were treated at academic/research centers. A potential hypothesis for this trend is increased access to specialized, multidisciplinary care and clinical trials.

Analysis of cathepsin S expression in gastric adenocarcinoma and in Helicobacter pylori infection.

Recent experimental studies have suggested a potential link between cathepsin S (CTTS) and gastric adenocarcinoma progression. Herein, we aimed to evaluate the expression of CTTS in gastric adenocarcinoma in patients who underwent curative-intent surgical resection. This was a cross-sectional study that included two groups: gastric adenocarcinoma (n = 42) and gastritis (n = 50). The gastritis group was then subdivided into H. pylori-positive (n = 25) and H. pylori-negative (n = 25) groups. Gastric tissue samples were analysed to determine CTTS expression through immunohistochemistry. Samples were obtained by oesophagogastroduodenoscopy or surgical specimens. In patients with gastritis, the age ranged from 18 to 78 years. Among them, 34% were male, and 66% were female. In patients with gastric adenocarcinoma, the age ranged from 37 to 85 years. Among them, 50% were male. When comparing the expression of CTTS between the two groups, only 16% of the gastritis samples had an expression higher than 25%. Alternatively, among patients with gastric adenocarcinoma, 19% had expression between 25-50%, 14.3% between 51-75%, and 26.2% had expression higher than 75% (p < 0.001). In the gastritis group, CTTS expression was significantly higher in patients with a positive test for H. pylori than negative test for H. pylori: 87.5% and 38.5%, respectively (p<0.001). There was no statistically significant association between CTTS positivity and clinicopathological variables, including tumour staging, histological type, angiolymphatic invasion, recurrence, current status and death. CTTS expression is higher in gastric adenocarcinoma samples. Patients with gastritis due to H. pylori also show a higher expression of CTTS than patients with negative results for this bacterium.