Site Of Metastatic Disease Research Articles

Understanding clonal heterogeneity and mechanisms of methotrexate resistance in two osteosarcoma PDX models.

e23512 Background: Osteosarcoma is a primary malignant bone tumor that is known to have significant intratumoral heterogeneity with branched cancer evolution. The lung is the most frequent site of metastatic disease and relapse occurs in more than 30 % children and young adults. It has been revealed that the metastatic ability and resistance of cancers including osteosarcoma might be due to the presence of a subset of cells within the intra-tumorally heterogeneous population. We investigated the emergence of resistant clonal subpopulations following targeted methotrexate treatment in two patient derived xenograft (PDX) models in vitro and in vivo. Our aim was to not only track the subclonal population of cells that establish in the lungs but also to identify clonal drivers and the mutational signature of the genes and pathways involved in MTX resistance. Methods: We previously established 20 barcoded osteosarcoma PDX models and demonstrated that the application of methotrexate (MTX-IC95) treatment as a selective pressure in seven models produces clonal subpopulations that were more resistant to MTX. In the current work we used barcoded next generation and RNA sequencing techniques to map the clonal and transcriptomic architecture of MTX resistant single clones in M36 and OS252 PDX models. We next injected the barcoded PDX cells intratibially in twenty severe combined immunodeficiency disease (SCID) mice to track the clonal population/subpopulation of cells that metastasize to the lungs. Following primary tumor growth, limb amputation was carried out and mice were treated with methotrexate or vehicle for two weeks. Primary tumor, blood and lung samples were collected after death from metastasis or euthanasia. All samples collected were snap frozen in liquid nitrogen and stored at -800C. DNA and RNA was extracted and analyzed by PCR, NGS or WES to map clonality, mutational and evolutionary profiles. Results: MTX treated single clones showed diversity and barcode abundance when compared to vehicle; barcode abundance reduced in the resistant clonal subpopulations when compared to the vehicles. Ten unique subclones were shared in both vehicle and MTX resistant clones in M36 while OS252 had only one shared subclone respectively. More than 50% of the injected mice developed primary tumors and matched lung micrometastases. We are currently analyzing both targeted and RNA sequencing results to further understand clonality, the mutational signature of the genes (DHFR, MTR, FPGS, GGH) and pathways involved in MTX resistance. Conclusions: We investigated mechanism of methotrexate resistance in two barcoded PDX models in vitro and in vivo using cytotoxicity, next generation and RNA sequencing techniques. Targeted amplicon sequencing of key genes involved in antifolate pathway will yield new information on clonal evolution and mechanisms of resistance.

Efficacy and safety of fruquintinib plus investigator's choice of chemotherapy as second-line therapy in metastatic colorectal cancer: Updated results of a multicenter, single-arm, phase 2 trial.

3571 Background: Fruquintinib, a potent and highly selective vascular endothelial growth factor receptor (VEGFR) inhibitor, combined with investigator’s choice of chemotherapy as second-line therapy in patients (pts) with metastatic colorectal cancer (mCRC) showed promising efficacy in preliminary analysis (2023 ASCO Poster-3582) of the prospective, open-label, multicenter, single-arm phase 2 trial (ChiCTR2200059280). Here we reported the updated efficacy data. Methods: Pts with mCRC progressed after first-line prior systemic treatment were administered fruquintinib (5~3 mg, d1-21, q4w) and investigator’s choice of chemotherapy (fluorouracil ± irinotecan ± oxaliplatin, d1, q3w) for up to 8 cycles. Patients without disease progression (PD) were followed by fruquintinib maintenance until PD or unacceptable toxicities. The primary endpoint was progression-free survival (PFS). The secondary endpoints included objective response rate (ORR), disease control rate (DCR), duration of response (DoR), overall survival (OS) and safety. Results: From November 2021 to November 2023, 100 pts were enrolled. Median age was 63 years (IQR, 56.5-71) and 61.0% were male. The left colon cancer involved in 77.0% pts. All pts had MSS/pMMR phenotype and 37.0% had RAS/BRAF-mutated tumors. 9.0% received prior anti-EGFR and 55.0% received anti-VEGF therapy. Most common sites of metastatic disease were liver (57.0%) and lung (41.0%). As of January 20, 2024, with a median follow-up of 9.3 mo, the median PFS was 6.9 mo (95%CI, 5.2-8.6), median OS was 20.1 mo (95%CI, 13.7-26.3). ORR was 26.0% (95%CI, 17.9-36.2), DoR was 11.3 mo (95%CI, 8.6-14.0), and DCR was 83.3% (95%CI, 74.0-89.9) in 96 efficacy-evaluable pts. The incidence of adverse events was comparable to the known toxicities associated with fruquintinib and chemotherapy. No treatment-related deaths occurred. Grade 3/4 adverse effects occurred in 33 pts (33.0%), and most commonly were neutropenia (21.0%), leukopenia (14.0%), thrombocytopenia (6.0%), proteinuria (5.0%), hypothyroidism (3.0%), diarrhea (2.0%), hand-foot syndrome (2.0%) and hypertension (1.0%). Conclusions: Fruquintinib combined with investigator’s chemotherapy followed by fruquintinib maintenance as second-line therapy showed satisfactory anti-tumor activity, prolonged PFS and OS, and manageable safety profiles in pts with mCRC. Further analysis of all pts with long-term follow-up will be presented in the future. Clinical trial information: ChiCTR2200059280.

Causes of death and patterns of metastatic disease at the end of life for patients with advanced melanoma in the immunotherapy era.

e21522 Background: Despite the drastic improvement in survival of patients with metastatic melanoma from immune checkpoint inhibitors (ICIs), almost half of patients still die from their disease. Factors surrounding death including mechanisms of death, sites of disease, and settings of death remain poorly described. A better understanding of these factors is paramount to optimize management for these patients. Methods: A retrospective observational cohort study was performed for patients age > 18 who died after treatment for advanced melanoma with anti-PD1 therapy or ipilimumab + nivolumab (Ipi/Nivo) at Yale Cancer Center (YCC) between 1/2009 and 6/2023. Primary outcome was cause of death. Statistical analyses were performed with Stata SE, version 15.0 (StataCorp, College Station, TX). This study was approved by the Yale Institutional Review Board (Protocol #2000034631). Results: Overall, 287 patients with melanoma who received ICIs were documented to be deceased; 183 met inclusion criteria. Median time from metastatic diagnosis to death was 16.1 mos (range 0.3 to 135.1 mos). Median age at death was 70 (range 22-101), 62.8% were male, and 90.2% were white. Most patients (52.5%) received Ipi/Nivo first line, and 79.8% of patients received both anti-PD1 and anti-CTLA4 treatment at some point. The median number of metastatic sites at death was 4 (range 0-13). The majority (90.1%) of patients with measurable disease had multi-system involvement of melanoma. Eleven patients had no evidence of disease at death and died due to non-melanoma causes. The most common sites of metastatic disease at death were distant lymph nodes (62.8%), lung (57.9%), liver (50.8%), brain (38.8%), and bone (37.7%). In total, 80.3% (147/183) experienced hospitalization within 3 months prior to death or hospice enrollment. Most died in the hospital (31.7%) or while enrolled in hospice (31.2% inpatient vs. 29.4% home). Overall, 10.9% of patients had survival > 5 years after metastatic diagnosis; 76.2% of long-term survivors died due to melanoma. Of 174 patients with evaluable causes of death, 87.9% of deaths were due to melanoma (Table 1). Patients with pleural metastases were more likely to die of respiratory failure (p = 0.036, OR 2.41 95% CI 1.06-5.50). Conclusions: The majority of deaths were a consequence of metastatic melanoma, with the most common causes including FTT, respiratory failure, and infection. [Table: see text]

Abstract PO4-15-01: A multi-center prospective cohort study to evaluate the presence of circulating tumor cells using the Epic Sciences platform among women with metastatic breast cancer

Abstract Background: The presence of tumor cells (or their components) in the blood of women with a history of early breast cancer has the potential to herald the development of metastatic recurrence at its earliest stages. Such early detection could potentially lead to novel prevention strategies, but it requires a sensitive assay. Objective: To use the Epic Sciences platform to detect and enumerate CTCs in blood samples from patients with an established diagnosis of metastatic breast cancer (MBC), prior to initiation of 1st line systemic therapy in the metastatic setting. Methods: We conducted a multi-center prospective cohort study to evaluate the presence of CTCs using the Epic Sciences platform among patients with a new diagnosis of MBC. Men or women age 18 to 85 were included, irrespective of breast cancer subtype. Patients with a prior or concurrent malignancy whose natural history or treatment had the potential to interfere with the detection of MBC in a liquid biopsy were excluded. A one-time blood draw was performed before patients received any local or systemic therapy in the metastatic setting. In addition, those with recurrent disease must have been off any systemic adjuvant therapy for ≥3 weeks prior to blood collection. Two 5 mL blood samples were obtained for CTC identification and enumeration. CTC identification was based on immunofluorescence analysis using Epic Sciences platform as previously described (Ueno et al 2017). The presence of CTCs was correlated with clinical and pathological features, which were abstracted from medical records and pathology reports. The association between the presence of CTCs and clinical/pathologic characteristics was tested using Fisher’s exact test for categorical variables and t-test or Wilcoxon rank sum tests for numerical variables. All analyses were performed using the R software package. Results: 100 patients were recruited between February 2021 and January 2023 at five academic oncology centres in Ontario and Quebec, Canada. 95 patients had evaluable blood for analysis and 5 did not due to blood age and/or insufficient blood volume. Six patients were excluded after providing a blood sample because tissue biopsy ultimately revealed a 2nd primary tumor (n=4) or benign tissue (n=2). Hence, 89 patients with a clinical diagnosis of MBC and with evaluable blood for CTC analyses were ultimately included in our cohort. The average age of patients was 61 years. Most patients (n=49, 55%) had a prior history of early breast cancer, 38 (43%) had de-novo metastatic disease and prior breast cancer history was unknown for 2 patients. 50 (66%) of patients had visceral metastatic disease. The most common sites of metastases included bone (62%), lung (30%), liver (29%) and lymph nodes (17%). 63 of 89 patients (71%) had detectable CTCs at baseline, prior to any local or systemic treatment in the metastatic setting. The median number of detectable CTCs per 5mL sample was 2 (IQR 8.5) and the range was 0 – 12,798. Twenty nine of 89 (33%) patients had 5 or more CTCs detected per 5ml blood. The proportion of patients with detectable CTCs was numerically highest (n=39/51, 76%) among patients with hormone receptor (HR)+/HER2-ve breast cancer, followed by HER2+ (n=16/22, 73%) and triple negative (n=8/13, 62%) disease. Associations between CTC detection with prior history of early breast cancer, sites of metastatic disease and disease burden will also be presented. Conclusions: Approximately 3 in 4 women with newly diagnosed metastatic breast cancer have detectable CTCs using the Epic Sciences platform prior to initiation of first line systemic therapy. CTCs may be a promising tool for the monitoring of breast cancer recurrence and will be investigated in an ongoing Canadian prospective observational study that aims to elucidate biomarkers of late breast cancer recurrence. Citation Format: Katarzyna Jerzak, Pamela Goodwin, Marguerite Ennis, Christine Brezden-Masley, Nathaniel Bouganim, Mark Basik, Arushi Jain, Giuseppe Di Caro, Rick Wenstrup, Nadine Hartmann, Megan Slade, Ana Elisa Lohmann. A multi-center prospective cohort study to evaluate the presence of circulating tumor cells using the Epic Sciences platform among women with metastatic breast cancer [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 PO4-15-01.

Abstract PO3-09-04: Identification of germline pathogenic variants to guide systemic therapy: Prevalence and spectrum of PVs among Mexican patients with metastatic breast cancer

Abstract BACKGROUND Currently, international genetic cancer risk assessment (GCRA) guidelines recommend genetic testing for the identification of germline pathogenic variants (PVs) in patients with metastatic breast cancer (MBC) to guide systemic therapy. Patients with PVs in BRCA genes are candidates to receive poly(adenosine diphosphate–ribose) polymerase inhibitors (PARPi). The prevalence of PVs in patients with HER2-negative MBC has been reported to be 10%. The proportion of MBC in low- and middle-income countries (LMIC) is higher. However, access to genetic testing in LMIC is limited and contributes to the gap in genetic epidemiology knowledge. We aimed to describe the frequency of germline PVs in breast cancer associated genes and clinic-pathologic characteristics of Mexican women with MBC. METHODS This retrospective study included Mexican women from 7 centers in Mexico, who were diagnosed with MBC and had genetic testing. Pathogenic and likely pathogenic variants were reported. Demographic, histopathological characteristics, family history and access to treatment with PARPi, were obtained from chart review. RESULTS From August 2017 to May 2023, 114 Mexican women with MBC were included, median age at diagnosis was 47 years (range 24-80 y), 42% had de novo metastatic, and 58% recurrent disease. 86.8% had infiltrating ductal carcinoma, 51.3% had HR+HER2- (n=58), 4.4% HR+HER+ (n=5), 5.3% HR-HER2+ (n=6), and 38.6% triple negative tumors (n=44). Sites of metastatic disease were as follows: 61.4% non-regional nodes (n=70), 57% bone (n=65), 40.3% lung (n=46), 30.7% liver (n=35), 15.8% central nervous system (n=18) and 7% peritoneal carcinomatosis (n=8). The frequency of PVs was 22% (25/114); 84% of the PVs were heterozygous, mainly identified in BRCA genes (BRCA1 n=12, BRCA2 n=9), and in 4 patients in other genes (PALB2 n=2, PTEN n=1, MUTYH n=1). Among PARPi candidates, 40% (10/25) received Olaparib, the majority received it on the second or subsequent lines of treatment (7/10) with a median progression free survival of 6 months (3-13 m). BRCA carriers were younger at BC diagnosis (38.5 vs. 49 years, p=0.00694) and had a significant higher proportion of family history of ovarian cancer (p=0.00039), but not for breast (p=0.06), prostate (p=0.71) or pancreatic cancer (p=0.098), compared to non-carriers. CONCLUSION We found a high frequency of PVs in BRCA genes in Mexican women with MBC. Access to the genetic testing and targeted therapy should be improve in the Mexican population in order to decrease disparities in cancer care in the Mexican Population. In addition, genetic testing allows to identify other family members at risk with cascade testing and to recommend them risk reduction strategies. Citation Format: Jose Luis Rodriguez-Olivares, Maria Fernanda Esparza-Orozco, Jose Alfredo Ramirez-Gonzalez, Roberto Ivan Sanchez-Reyes, Enrique Isay Talamantes-Gamez, Gregorio Quintero-Beulo, Gilberto Lopez-Rosas, Karla Alicia Centelles-López, Brizio Moreno-Jaime, Daniela Vazquez-Juarez, Ana Maria Hernandez-Murillo, Ilana de la Puente Tawil, Jeffrey Weitzel, Cynthia Villareal Garza, Yanin Chavarri-Guerra. Identification of germline pathogenic variants to guide systemic therapy: Prevalence and spectrum of PVs among Mexican patients with metastatic breast cancer [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 PO3-09-04.

Abstract PO2-06-01: Validity of patient-reported data from long-term survivors of metastatic breast cancer

Abstract Background: Metastatic Breast Cancer is incurable, with 5-year survival of ~30%. The Outliers Study recruited participants with metastatic breast cancer to fill out an extensive survey to better elucidate how clinical, social, and genetic factors affect metastatic breast cancer survivorship. Patient-reported surveys can be a valuable source of data for research studies and cancer registries to further our understanding of disease, but concerns regarding the validity of patient reporting remain. Beatty et al. (2022) suggest that patients with early stage breast cancer are reliable reporters of disease recurrence (79% accuracy rate), but no study to our knowledge has evaluated the validity of reporting regarding metastases, or those who are long-term survivors. In this study, over 1000 women with metastatic breast cancer filled out an extensive survey. We compared the medical records with self-reported data on clinical history to assess concordance. Objective: To determine the validity of patient-reported data pertaining to a wide variety of oncologic information, including but not limited to primary diagnosis date, stage, hormone status, metastatic date, site, and post-metastatic chemotherapy regimens, in long term survivors of metastatic breast cancer. Methods: Patients with metastatic breast cancer were recruited for the nation-wide Outliers Study to fill out an extensive survey on their oncologic history. Of >1000 participants enrolled in the Outliers Study, we identified a subpopulation of those who had lived the longest with metastatic disease and named this cohort “Long Term Survivors” (LTS). We acquired either partial or complete oncologic medical records from 31 LTS in order to determine the validity of patient-reported survey responses. Table 1 describes the details of this LTS cohort (n=31). We then compared each LTS survey to the medical record to verify responses and identify any inaccuracies. We also assessed accuracy to compare those who did and did not consult their medical records while responding to the survey. Results: Of the verifiable survey responses, we identified 592 accurate responses and 5 inaccuracies, yielding a 99.2% accuracy rate of patient-reported oncologic data. The identified errors included 2 minor discrepancies in clinical detail, 2 false-negative reports and 1 false-positive report. Specifically, there were minor discrepancies regarding biopsy type (i.e. core biopsy reported instead of fine needle) and site of radiation (e.g. “chest wall” instead of T12 vertebrae). The false-negative reporters failed to report 1) a positive history for surgery distant from breast for metastatic disease and 2) a positive history of biopsy for disease distant to the breast. The false positive error was a report of “surgery on distant metastasis” for a history of bone marrow biopsy. Each error identified was made by a separate participant and we found no association between patients who were reporting from memory and patients who reported an inaccurate response. Of note, there were no inaccurate responses identified pertaining to the topics of initial diagnosis date, stage, and histologic type, breast surgical history, hormone and HER2 receptor status of initial and metastatic disease, date and site of metastatic disease, BRCA mutation status, date and regimens of chemotherapy, and date of radiation history. Conclusion: Long term survivors of metastatic breast cancer report clinical data spanning a wide range of oncologic topics with high accuracy. The majority of errors identified in patient reported survey responses were minor and suggested misunderstandings of medical nomenclature (surgery vs biopsy; core vs FNA) and anatomic specificity. The topic of biopsy was most prone to error. Notably, we found no association between errored responses and patients who reported from memory without referencing their medical records. Table 1 Citation Format: Meredith Gallagher, Mark Burkard. Validity of patient-reported data from long-term survivors of metastatic breast cancer [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 PO2-06-01.

METASTATIC DISEASE OF THE PROXIMAL FEMUR: MANAGEMENT AND OUTCOMES IN A REGIONAL CANCER CENTRE

The burden of metastatic disease presenting with axial skeleton lesions is exponentially rising predominantly due to advances in oncological therapies. A large proportion is these lesions are located in the proximal femora, which given its unique biomechanical architecture is problematic.These patients are frequently comorbid and require prompt and concise decision making regarding their orthopaedic care in line with recent British Orthopaedic Association guidelines.We present data detailing the outcomes for patients with proximal femoral metastatic disease referred and treated over a three year period in an Regional Cancer Centre.We retrospectively reviewed a prospectively maintained database of all patients referred for discussion at MDT with axial skeletal metastatic disease. From this we isolated patients with femoral disease. Demographic data along with primary tumour and metastatic disease site were assessed. Treatment regimens were analysed and compared. Finally predicted and actual mortality data was collated.331 patients were referred over the analysed time period, of which 99 had femoral disease. 66% of patients were managed conservatively with serial monitoring while 34% underwent operative treatment. 65% of those received an intramedullary fixation while 35% had arthroplasty performed. There was a 51:49 split male to female with Prostate, Lung and Breast being the predominant primary tumours. Concurrent spinal metastatic disease was noted in 62% of patients while visceral mets were seen in 37%. Mortality rate was 65% with an average prognosis of 388 days (1.06years) while average mortality was noted within 291 days (0.8 years).Proximal femoral metastatic disease accounts for a large volume of the overall mets burden. There is an overall tendency towards conservative management and of those requiring surgery IM nailing was the treatment of choice. The data would indicate that outcomes for these patients are guarded and on average worse than those predicted.

Abstract PO4-07-11: FDG-PET is superior to bone scintigraphy for the detection of bone metastases in breast cancer patients

Abstract Background: Bone is the commonest site for metastases in breast cancer patients, with up to 44% of patients having bone as their sole site of metastatic disease. Patients are at increased risk of morbidity from skeletal related events (SRE) from bone metastases due to pathological fractures and spinal cord compression. Early diagnosis is crucial so that bone modifying agents can be used to prevent SREs and other agents such as CDK4/6 inhibitors can be considered. Bone scintigraphy is the most widely performed first investigation for patients at high risk or symptomatic from bone metastases. Methods: We performed a meta-analysis comparing FDG-PET and bone scintigraphy using PubMed, Science Direct, and Embase for the literature search. 1009 patients were included in the study. Data for 2 × 2 contigency tables was selected and QUADAS-2 was used for quality assessment. Diagnostic accuracy was performed using Graph pad Prism 9.5.1 and R studio 2022. Pooled sensitivity and specificity of FDG-PET/CT was 96.6% (95% CI=91.5%-98.7%) and 96.8% (95% CI=82.1%-99.5%) respectively. Respective results for BS were 88.3% (95% CI=79.8%-93.5%) and 81.3% (95% CI=63.1%-91.7%). Sensitivity and specificity of FDG-PET/CT was significantly higher than BS (P=0.0063, P= 0.0068, respectively). The diagnostic odds ratio and area under ROC curve were significantly higher for FDG-PET/CT than BS (654.36 vs 35.24, and 0.980 vs 0.877, respectively). Conclusion: FDG-PET is superior to bone scinitigaphy for the detection of bone metastases in breast cancer.The benefits of replacing BS with FDG-PET/CT are evident. However othere technologies such as DW-MRI should be considered. Large multicentre prospective trials with strict FDG-PET/CT imaging protocols compared to DW-MRI both for disease detection and monitoring of response are required to strengthen the evidence in this field, to help inform imaging guidelines and best practices in the future. Newer technologies such as [18F]estradiol (FES)-PET and [18F]GE-226 for HER2 expression also warrant further investigation in ER positive and HER2 positive breast cancer. Citation Format: Laura Kenny, Maisher Tin-U. FDG-PET is superior to bone scintigraphy for the detection of bone metastases in breast cancer patients [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 PO4-07-11.

Use of Natural Language Processing to Infer Sites of Metastatic Disease From Radiology Reports at Scale.

To evaluate natural language processing (NLP) methods to infer metastatic sites from radiology reports. A set of 4,522 computed tomography (CT) reports of 550 patients with 14 types of cancer was used to fine-tune four clinical large language models (LLMs) for multilabel classification of metastatic sites. We also developed an NLP information extraction (IE) system (on the basis of named entity recognition, assertion status detection, and relation extraction) for comparison. Model performances were measured by F1 scores on test and three external validation sets. The best model was used to facilitate analysis of metastatic frequencies in a cohort study of 6,555 patients with 53,838 CT reports. The RadBERT, BioBERT, GatorTron-base, and GatorTron-medium LLMs achieved F1 scores of 0.84, 0.87, 0.89, and 0.91, respectively, on the test set. The IE system performed best, achieving an F1 score of 0.93. F1 scores of the IE system by individual cancer type ranged from 0.89 to 0.96. The IE system attained F1 scores of 0.89, 0.83, and 0.81, respectively, on external validation sets including additional cancer types, positron emission tomography-CT ,and magnetic resonance imaging scans, respectively. In our cohort study, we found that for colorectal cancer, liver-only metastases were higher in de novo stage IV versus recurrent patients (29.7% v 12.2%; P < .001). Conversely, lung-only metastases were more frequent in recurrent versus de novo stage IV patients (17.2% v 7.3%; P < .001). We developed an IE system that accurately infers metastatic sites in multiple primary cancers from radiology reports. It has explainable methods and performs better than some clinical LLMs. The inferred metastatic phenotypes could enhance cancer research databases and clinical trial matching, and identify potential patients for oligometastatic interventions.

Molecular targets and mechanisms of different aberrant alternative splicing in metastatic liver cancer.

Metastasis remains a major challenge in the successful management of malignant diseases. The liver is a major site of metastatic disease and a leading cause of death from gastrointestinal malignancies such as colon, stomach, and pancreatic cancers, as well as melanoma, breast cancer, and sarcoma. As an important factor that influences the development of metastatic liver cancer, alternative splicing drives the diversity of RNA transcripts and protein subtypes, which may provide potential to broaden the target space. In particular, the dysfunction of splicing factors and abnormal expression of splicing variants are associated with the occurrence, progression, aggressiveness, and drug resistance of cancers caused by the selective splicing of specific genes. This review is the first to provide a detailed summary of the normal splicing process and alterations that occur during metastatic liver cancer. It will cover the role of alternative splicing in the mechanisms of metastatic liver cancer by examining splicing factor changes, abnormal splicing, and the contribution of hypoxia to these changes during metastasis.

Immunological effects of radiopharmaceutical therapy.

Radiation therapy (RT) is a pillar of cancer therapy used by more than half of all cancer patients. Clinically, RT is mostly delivered as external beam radiation therapy (EBRT). However, the scope of EBRT is limited in the metastatic setting, where all sites of disease need to be irradiated. Such a limitation is attributed to radiation-induced toxicities, for example on bone marrow and hematologic toxicities, resulting from a large EBRT field. Radiopharmaceutical therapy (RPT) has emerged as an alternative to EBRT for the irradiation of all sites of metastatic disease. While RPT can reduce tumor burden, it can also impact the immune system and anti-tumor immunity. Understanding these effects is crucial for predicting and managing treatment-related hematological toxicities and optimizing their integration with other therapeutic modalities, such as immunotherapies. Here, we review the immunomodulatory effects of α- and β-particle emitter-based RPT on various immune cell lines, such as CD8+ and CD4+ T cells, natural killer (NK) cells, and regulatory T (Treg) cells. We briefly discuss Auger electron-emitter (AEE)-based RPT, and finally, we highlight the combination of RPT with immune checkpoint inhibitors, which may offer potential therapeutic synergies for patients with metastatic cancers.

Abstract 148: Multiomic sequencing reveals diversity in clonal landscape and genomic alterations in a lung metastatic PDX osteosarcoma model

Abstract Introduction: Osteosarcoma is a primary malignant bone tumor characterized by the production of spindle cells resulting in immature bone formation. The lung is the most frequent site of metastatic disease and relapse occurs in more than 30 % of patients. Recent results show that relapse is due to a subset of cells with different phenotypic and genetic signatures conferring advantage to drive progression and drug resistance within the intra-tumorally heterogeneous population. Thus, developing a defined in vivo model that can identify the rare genetic subpopulation and recapitulate clonal evolution is crucial. In this study, we used whole exome, barcode and RNA sequencing to characterize the landscape of genomic alterations and also track and identify the clonal subpopulations, clonal and genetic drivers of lungs metastasis. Methods: We injected barcoded PDX (OS17) cells intravenously in ten SCID mice to track the clonal subpopulation of cells that metastasize to the lungs. Metastasized lung nodules were collected following death or euthanasia. All samples collected were snap frozen in liquid nitrogen and stored at -80°C. DNA and RNA was extracted and analyzed by PCR, NGS, WES and RNA sequencing to map clonality, mutational and evolutionary profiles. Results: Four (40%) of the mice developed lung metastases with three mice having multiple metastatic lung nodules. Surgery to remove the metastatic nodules was performed 216 ± 55.5 days following tumor cell injection. Nine metastatic lung nodules from three mice were used for sequencing and analysis. A Shannon-Weaver and Jaccard similarity index show a diversity in clonal architecture between the lung nodules. A total of 15,394 somatic variants was identified including 12,547 single nucleotide variants (SNV), 4054 synonymous, 2662 missense, 28 nonsense mutations and 1639 somatic indels. The SNVs accounted for 81% of all variants followed by CNV 11 % and indels 8% respectively. Synonymous and missense mutations were the most frequently observed in all samples. Copy number loss was two-fold compared to copy number gain across all tumors. Furthermore, the deletions span longer genomic distances compared to amplifications. The mutational spectrum showed that the highest substitutions were C&amp;gt;T/G&amp;gt;A followed by T&amp;gt;C/A&amp;gt;G; the least substitutions were T&amp;gt;A/A&amp;gt;T. Also, we identified a large set of genes with genomic aberrations. These include amplifications in VEGF, RB1, RUNX, PARP4, ICAM3, EGFR, BRCA2, COLA6A1, COLA6A2, CCND3, CDKN2D etc. Conclusions: In the current model, we identified multiple tumorigenic seeding clones and the diverse set of genes mutated in osteosarcoma. Further analysis of the mutational signature resulted in the identification of potential genes that act as drivers in the lung metastatic process. Acknowledgments: Swim Across America, the Foster Foundation and the Barbara Epstein Foundation. Citation Format: Sylvester Jusu, Wendong Zhang, Zhongting Zhang, Xu Zhaohui, Sankaranarayanan Kannan, Yifei Wang, Zhou Xin, Yi Yanhua, Michael Roth, Jonathan Gill, Richard Gorlick. Multiomic sequencing reveals diversity in clonal landscape and genomic alterations in a lung metastatic PDX osteosarcoma model [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 148.

Nonmalignant 68 Ga-FAPI-46 Uptake in 2 Cases of TENIS Syndrome : Comparison With 18 F-FDG.

The cancer specificity of fibroblast activation protein inhibitor (FAPI) uptake remains understudied topic, and several cases of false-positive FAPI PET/CT findings have been reported. We present 2 patients of differentiated thyroid cancer with thyroglobulin elevation and negative iodine scintigraphy syndrome who underwent 68 Ga-FAPI PET/CT and 18 F-FDG PET/CT for evaluation of any possible sites for metastatic disease. Although no focus of metastatic disease was found in these patients, remarkable findings were noticed instead. Nonmalignant FAPI uptake was evident in the gallbladder, uterus, and degenerative changes, whereas these uptake were discordant or partially concordant with those in FDG's, also CT images showed no underlying abnormality.

Liver Imaging in Gastroenteropancreatic Neuroendocrine Neoplasms.

The incidence of neuroendocrine neoplasms (NENs) has gradually increased over the past few decades with the majority of patients presenting with metastases on initial presentation. The liver is the most common site of initial metastatic disease, and the presence of liver metastasis is an independent prognostic factor associated with a negative outcome. Because NENs are heterogenous neoplasms with variable differentiation, grading, and risk of grade transformation over time, accurate diagnosis and management of neuroendocrine liver lesions are both important and challenging. This is particularly so with the multiple liver-directed treatment options available. In this review article, we discuss the diagnosis, treatment, and response evaluation of NEN liver metastases.

Real-World Data and Clinical Implications of Next-Generation Sequencing (NGS)-Based Analysis in Metastatic Breast Cancer Patients.

Over the last two decades, the use of Next-Generation Sequencing (NGS) in medical oncology has increased the likelihood of identifying druggable mutations that may be potentially susceptible to targeted treatments. The European Society for Medical Oncology (ESMO) currently does not recommend the use of the NGS test to determine the therapeutic course of patients with metastatic breast cancer (mBC) in daily clinical practice. However, the aim of this work is to evaluate the potential contribution of the NGS test in selecting targeted therapies for patients with mBC. Data were retrospectively collected from 101 patients diagnosed with metastatic breast cancer and treated at the Modena Cancer Center between January 2015 and April 2022. A NGS test was performed on the tumor tissue of each patient at the Laboratory of Molecular Pathology of the University Hospital of Modena. This study analyzed the clinical-pathological characteristics and mutational profile of the population using NGS tests, with a focus on actionable mutations that could be targeted in advanced stages of clinical development. The indicator of this study was to quantify the actionable mutations that resulted in a change of cancer treatment. In total, 101 patients with metastatic breast cancer were analyzed, including 86 with luminal phenotype, 10 who were HER2-positive and 5 who were triple-negative. Median age was 52 years. NGS analysis was conducted on 47 samples of primary breast cancer, 52 on metastatic sites of disease and 2 on liquid biopsies. A total of 85 gene mutations were found. The most common mutations were identified in the PIK3CA (47%), FGFR (19%) and ERBB2 genes (12%), and to a lesser extent in other genes. Of the 61 patients with pathogenic mutations, 46 (75%) had at least one actionable mutation. Of these, nine received treatment with a molecular target drug: eight patients with a mutation of the PIK3CA gene were treated with alpelisib and fulvestrant; one patient with FGFR1/2 amplifications received TAS120. Median PFS for these patients was 3.8 months. The study results show that using the NGS test on cancer tissue of metastatic breast cancer could influence the therapeutic choices, considering the small sample size and limited follow-up. About 9% of the study population had their therapy modified based on the results of NGS. The growing number of detectable mutations and increased accessibility of the test may lead to a greater number of potential therapeutic implications for the NGS assay. Perspectives suggest that NGS analysis can be implemented in daily clinical practice, particularly in contexts where a Molecular Tumor Board (MTB) is active.

Alliance for clinical trials in Oncology (Alliance) trial A022101/NRG-GI009: a pragmatic randomized phase III trial evaluating total ablative therapy for patients with limited metastatic colorectal cancer: evaluating radiation, ablation, and surgery (ERASur)

BackgroundFor patients with liver-confined metastatic colorectal cancer (mCRC), local therapy of isolated metastases has been associated with long-term progression-free and overall survival (OS). However, for patients with more advanced mCRC, including those with extrahepatic disease, the efficacy of local therapy is less clear although increasingly being used in clinical practice. Prospective studies to clarify the role of metastatic-directed therapies in patients with mCRC are needed.MethodsThe Evaluating Radiation, Ablation, and Surgery (ERASur) A022101/NRG-GI009 trial is a randomized, National Cancer Institute-sponsored phase III study evaluating if the addition of metastatic-directed therapy to standard of care systemic therapy improves OS in patients with newly diagnosed limited mCRC. Eligible patients require a pathologic diagnosis of CRC, have BRAF wild-type and microsatellite stable disease, and have 4 or fewer sites of metastatic disease identified on baseline imaging. Liver-only metastatic disease is not permitted. All metastatic lesions must be amenable to total ablative therapy (TAT), which includes surgical resection, microwave ablation, and/or stereotactic ablative body radiotherapy (SABR) with SABR required for at least one lesion. Patients without overt disease progression after 16–26 weeks of first-line systemic therapy will be randomized 1:1 to continuation of systemic therapy with or without TAT. The trial activated through the Cancer Trials Support Unit on January 10, 2023. The primary endpoint is OS. Secondary endpoints include event-free survival, adverse events profile, and time to local recurrence with exploratory biomarker analyses. This study requires a total of 346 evaluable patients to provide 80% power with a one-sided alpha of 0.05 to detect an improvement in OS from a median of 26 months in the control arm to 37 months in the experimental arm with a hazard ratio of 0.7. The trial uses a group sequential design with two interim analyses for futility.DiscussionThe ERASur trial employs a pragmatic interventional design to test the efficacy and safety of adding multimodality TAT to standard of care systemic therapy in patients with limited mCRC.Trial registrationClinicalTrials.gov: NCT05673148, registered December 21, 2022.

Survival outcomes in patients (pts) with prostatic cancer (PCa) based on pathologically confirmed sites of metastasis.

72 Background: In a meta-analysis of 9 phase III trials involving 8,820 pts with metastatic castration-resistant prostate cancer, overall survival progressively decreased from those with lymph node only disease to those with bone, lung, and liver metastases. Herein, we aimed to validate these results in a large real-world dataset based on pathologically confirmed site of metastasis. Methods: PCa tissue specimens derived from the primary Pca (PPCa) and metastatic sites were molecularly profiled by Caris Life Sciences (Phoenix, AZ). Overall survival (OS) was assessed using insurance claims data, with OS calculated from date of initial tumor diagnosis to death or lost to follow-up using Kaplan Meier estimates and log-rank test. Molecular and immunologic differences by specific metastatic site are presented in a companion abstract. All the analyses were done using CODEai. Results: 6,069 PCa specimens were included in the analysis [n= 3,411 prostate, n=1,634 non-visceral (bone and lymph node), n=1,029 visceral disease (lung, liver, peritoneum, brain, other.)]. PCa specimens (n=6,069) were stratified based on tumor biopsy site, including prostate (n= 3411), NV (bone and lymph node; n=1,631), and visceral (lung, liver, peritoneum, brain, other; n=1027) subgroups. The median OS from initial diagnosis was significantly longer for pts with PPCa compared to those with visceral metastatic PCa (median OS 70.2 vs 55.5 months; HR 1.42, 95% CI: 1.28-1.58, p&lt;0.001) as well as non-visceral PCa (median OS 70.2 vs 63.9 months; HR 1.15, 95% CI: 1.05 – 1.27, p=0.004). The comparison of median OS by site of metastatic disease compared to bone metastasis is presented in the Table. Conclusions: We validate the results of prior studies in a real-world PCa population and show differential OS based on the site of metastases, with liver metastases associated with the shortest OS and lung metastases showing the longest OS. These data argue against combining liver and lung metastases into a single category of visceral metastases when visceral metastasis is used as stratification factor for randomized trials. [Table: see text]

Immunoembolization for the Treatment of Uveal Melanoma Hepatic Metastases.

Uveal melanoma is the most common primary intraocular tumor in adults. Approximately 50% of patients develop metastatic disease despite successful treatment of the primary eye tumor. The liver is the most common site of metastatic disease occurring in more than 90% of patients. Clinical prognosis is dependent on the ability to control the growth of liver tumors. Locoregional therapies play an important role in stabilizing liver metastases, prolonging survival for patients with metastatic uveal melanoma. As overall survival is prolonged, the development of extrahepatic disease becomes more common. Immunoembolization, a form of liver-directed therapy, not only focuses on treating hepatic metastases by stimulating the local immune system to suppress the growth of liver tumors, but it potentially generates a systemic immune response delaying the growth of extrahepatic metastases as well. The following article discusses immunoembolization for the treatment of metastatic uveal melanoma including the rationale, mechanism of action, indications, contraindications, outcomes, and associated toxicities.

Cryoablation for the treatment of breast cancer: immunological implications and future perspectives.Utopia or reality?

Cryoablation is a minimally invasive technique currently employed in breast cancer care, that uses freeze and thaw cycles to treat benign breast lesions, small breast cancers or focal sites of metastatic disease in patients not eligible for surgery. The final goal of this procedure is to destroy breast cancer cells using extreme cold. In addition, several studies have shown that this technique seems to have an enhancing effect on the immune response, especially by increasing the expression of tumor neoantigens specific to tumor cells, which are then attacked and destroyed. Exploiting this effect, cryoablation in combination with immunotherapy could be the key to treating early-stage breast cancers or patients who are unsuitable for surgery. According to some recent studies, there are other potential tools that could be used to enhance the therapeutic effect of cryoablation, such as FE3O4 nanoparticles or the manipulation of aquaporin expression. The aim of this narrative review is to summarize the current evidence regarding the use, indications, advantages and disadvantages of cryoablation in the treatment of breast cancer.

Alliance A022101: A pragmatic randomized phase III trial evaluating total ablative therapy for patients with limited metastatic colorectal cancer—Evaluating radiation, ablation, and surgery (ERASur).

TPS236 Background: For patients with oligometastatic colorectal cancer (CRC), aggressive local therapy of isolated metastases, particularly in the liver, has been associated with long-term progression-free survival and overall survival (OS) primarily based on retrospective evidence. However, in patients with limited metastatic CRC that is deemed inoperable or those with additional disease outside of the liver or lungs, the role of local ablative therapies, including microwave ablation (MWA) and stereotactic body radiation therapy (SBRT), to render patients disease free is less clear. Further, despite the long history of treating oligometastatic CRC with local therapy, which is provider biased and not evidence based, questions remain regarding the benefit of extending the paradigm of metastatic directed therapy to patients with more extensive disease. This trial seeks to use a pragmatic multimodality approach that mirrors the current clinical dilemma. This study is designed to evaluate the safety and efficacy of adding total ablative therapy (TAT) of all sites of disease to standard of care systemic treatment in those with limited metastatic CRC. Methods: A022101 is a National Clinical Trials Network randomized phase III study planned to enroll 364 patients with newly diagnosed metastatic CRC (BRAF wild-type, microsatellite stable) with ≤4 sites of metastatic disease on baseline imaging. Liver-only metastatic disease is not permitted, and lesions must be amenable to any combination of surgical resection, MWA, and/or SBRT with SBRT required for at least one lesion. Patients receive first-line systemic therapy for 4-6 months and are then randomized 1:1, stratified by number of metastatic organ sites (1-2 vs. 3-4), timing of metastatic disease diagnosis (de novo vs. secondary), and presence of metastatic disease outside the liver and lungs in at least one site. Patients in Arm 1 will receive TAT which consists of treatment of all metastatic sites with SBRT ± MWA ± surgical resection followed by standard of care systemic therapy. Patients in Arm 2 will continue with standard of care systemic therapy alone. The primary endpoint is OS. Secondary endpoints include event-free survival, treatment-related toxicities, and local recurrence with exploratory biomarker analyses. The study needs 346 evaluable patients combined in the 2 arms to demonstrate an improvement in OS with a hazard ratio of 0.7 to provide 80% power with a one-sided alpha of 5%. The trial utilizes a group sequential design with two interim analyses (25% and 50% of events) for futility. The trial activated in January 2023 and recruitment is ongoing. Support: U10CA180821, U10CA180882; https://acknowledgments.alliancefound.org. U10CA180820 (ECOG-ACRIN); U10CA180868 (NRG); U10CA180888 (SWOG). Clinical trial information: NCT05673148 .