Cancer Of Unknown Primary Research Articles

A case of laparoscopic lymphadenectomy for adenocarcinoma of unknown primary incidentally detected as a solitary enlarged lymph node along the common hepatic artery

BackgroundEven in cancer of unknown primary (CUP), which is rare clinical condition, solitary anterosuperior lymph node (LN) along the common hepatic artery (No.8a LN) enlargement diagnosed as metastatic adenocarcinoma has never been reported.Case presentationA 68-year-old Japanese male, with a history of early gastric cancer that had been completely treated by endoscopic submucosal dissection 26 years ago, was detected a single enlarged nodule along the common hepatic artery, No.8a LN, incidentally by computed tomography performed for monitoring of interstitial pneumonia. Endoscopic ultra-sound-guided fine needle aspiration revealed that this nodule was adenocarcinoma suggestive of metastasis, but other imaging studies, including upper and lower gastrointestinal endoscopy, positron emission tomography, and ultrasonography did not detect any primary cancer. We have finally diagnosed as the LN metastasis of CUP and performed laparoscopic lymphadenectomy for this tumor. The tumor was approximately 5 cm in size, was in close proximity to the pancreas, and involved part of the right gastric artery and vein. LNs in the No.5 and No.8a areas, including this tumor, were dissected laparoscopically, and radical resection was achieved. The patient had no postoperative complication and was discharged on postoperative day 10. Immunohistopathological findings revealed that the tumor was poorly differentiated adenocarcinoma, and different from the histology of gastric cancer resected 26 years ago, although the tumor was suggestive of gastrointestinal origin. Imaging studies performed 2 and 6 months after discharge also did not reveal a primary site.ConclusionWe reported a case of solitary No.8a LN adenocarcinoma of CUP. For diagnostic and therapeutic purposes, radical resection is recommended for single enlarged intra-abdominal LN of CUP.

A cfDNA methylation-based tissue-of-origin classifier for cancers of unknown primary

Cancers of Unknown Primary (CUP) remains a diagnostic and therapeutic challenge due to biological heterogeneity and poor responses to standard chemotherapy. Predicting tissue-of-origin (TOO) molecularly could help refine this diagnosis, with tissue acquisition barriers mitigated via liquid biopsies. However, TOO liquid biopsies are unexplored in CUP cohorts. Here we describe CUPiD, a machine learning classifier for accurate TOO predictions across 29 tumour classes using circulating cell-free DNA (cfDNA) methylation patterns. We tested CUPiD on 143 cfDNA samples from patients with 13 cancer types alongside 27 non-cancer controls, with overall sensitivity of 84.6% and TOO accuracy of 96.8%. In an additional cohort of 41 patients with CUP CUPiD predictions were made in 32/41 (78.0%) cases, with 88.5% of the predictions clinically consistent with a subsequent or suspected primary tumour diagnosis, when available (23/26 patients). Combining CUPiD with cfDNA mutation data demonstrated potential diagnosis re-classification and/or treatment change in this hard-to-treat cancer group.

Prediction of tumor origin in cancers of unknown primary origin with cytology-based deep learning.

Cancer of unknown primary (CUP) site poses diagnostic challenges due to its elusive nature. Many cases of CUP manifest as pleural and peritoneal serous effusions. Leveraging cytological images from 57,220 cases at four tertiary hospitals, we developed a deep-learning method for tumor origin differentiation using cytological histology (TORCH) that can identify malignancy and predict tumor origin in both hydrothorax and ascites. We examined its performance on three internal (n = 12,799) and two external (n = 14,538) testing sets. In both internal and external testing sets, TORCH achieved area under the receiver operating curve values ranging from 0.953 to 0.991 for cancer diagnosis and 0.953 to 0.979 for tumor origin localization. TORCH accurately predicted primary tumor origins, with a top-1 accuracy of 82.6% and top-3 accuracy of 98.9%. Compared with results derived from pathologists, TORCH showed better prediction efficacy (1.677 versus 1.265, P < 0.001), enhancing junior pathologists' diagnostic scores significantly (1.326 versus 1.101, P < 0.001). Patients with CUP whose initial treatment protocol was concordant with TORCH-predicted origins had better overall survival than those who were administrated discordant treatment (27 versus 17 months, P = 0.006). Our study underscores the potential of TORCH as a valuable ancillary tool in clinical practice, although further validation in randomized trials is warranted.

Transoral Robotic Surgery and Radiation Volume Deintensification in Unknown Primary Squamous Cell Carcinoma of the Neck

Patients with unknown primary squamous cell carcinoma (CUP) with cervical metastases typically receive comprehensive radiotherapy (RT) of the pharynx and bilateral neck. Typically, these patients receive comprehensive RT of the pharynx and bilateral neck that may produce treatment-related toxic effects. To determine whether localization of occult oropharyngeal cancers with transoral robotic surgery (TORS) combined with reduced pharyngeal and neck RT volumes provides acceptable disease control. This phase 2, single-group nonrandomized controlled trial at a single institution accrued 32 prospective participants with p16-positive CUP without a primary squamous cell carcinoma on examination and imaging from 2017 to 2019, and 24-month follow-up. The data analysis was conducted from January 2021 to June 2022. Diagnostic- (n = 13) or therapeutic-intent (n = 9) TORS, with pharyngeal-sparing radiotherapy (PSRT) prescribed for negative margins or pT0, and unilateral neck RT (UNRT) prescribed for unilateral lymphadenopathy with lateralized primary tumor or pT0. Out-of-radiation treatment volume failure (<15% was hypothesized to be acceptable) and reports of local and regional recurrence, overall survival, toxic effects, swallowing outcomes (per the MD Anderson Dysphagia Inventory), and videofluoroscopic swallow (per Dynamic Imaging Grade of Swallowing Toxic Effects [DIGEST]) ratings. The study sample comprised 22 patients (mean [SD] age, 59.1 [5.7] years; 3 [14%] females and 19 [86%] male) with CUP. Of these, 19 patients (86%) had tumor stage cN1; 2 (9%), cN2; and 1 (5%), cN3. Five patients (23%), 14 patients (64%), and 3 patients (13%) had 0, 1, or 2 primary tumors, respectively. Twenty patients received RT; of these, 9 patients (45%) underwent PSRT and 10 patients (50%), UNRT. In the diagnostic-intent group, 8 patients (62%) and 5 patients (38%) underwent RT and RT-concurrent chemotherapy, respectively. In the therapeutic-intent group, 6 patients (67%) and 1 patient (11%) received adjuvant RT-concurrent chemotherapy, respectively; 2 patients declined RT. Two-year out-of-radiation treatment volume failure, locoregional control, distant metastasis control, and overall survival were 0%, 100%, 95%, and 100%, respectively. Grade 3 or 4 surgical, acute, and late toxic effects occurred in 2 (9%), 5 (23%), and 1 (5%) patients, respectively. PSRT was associated with lower RT dose to superior constrictors (37 vs 53 Gy; mean difference, 16 Gy; 95% CI, 6.4, 24.9), smaller decline in swallowing scores during treatment (19.3 vs 39.7; mean difference, -20.4; 95% CI, -34.1 to -6.1), and fewer patients with worsening DIGEST grade on findings of videofluoroscopic swallow studies at 2 years (0% vs 60%; difference, 60%; 95% CI, 30% to 90%). These findings indicate that TORS for p16-positive CUP allows RT volume deintensification with excellent outcomes and support future investigation in randomized clinical trials. ClinicalTrials.gov Identifier: NCT03281499.

Utility of Bone Scan in Evaluating Patients with Clinically Indeterminate Diagnosis of Cancer in a Low-resource Practice

Context: A major indication for referrals for bone scans (BS) to establish or exclude skeletal metastases. Few patients are referred with clinically indeterminate diagnosis or cancer of unknown primary (CUP), to search for bony metastases or primary tumor. Aims: This study aimed to assess the usefulness or otherwise for BS in such instances. Settings and Design: A retrospective cross-sectional study of BS performed for CUP and indeterminate diagnosis from 2012 to 2016 in the nuclear medicine unit of a tertiary teaching hospital. Subjects and Methods: The study involved reviews of technetium-99m diphosphonate BS for patients with CUP. BSs were reported by nuclear physicians as normal, normal variants, suspicious for metastases or as malignant, and with solitary or multiple skeletal metastases. Statistical Analysis Used: Data were analyzed using SPSS version 21 for descriptive analysis. Continuous data were displayed as means along with their standard deviation; categorical data were tabulated as frequencies and percentages. Results: Of 2156 BS, 42 (0.02%) were eligible. Patients were aged 27–86 years, mainly in the sixth and seventh decades of life. Bone metastases were identified in 14 (33%) of these patients, whereas 17 BS (40%) were normal, BS appeared equivocal in 10 (23.8%). Conclusions: Single-photon emission computed tomography/computed tomography availability would resolve the clinical dilemma in patients with equivocal and apparently normal BS.

Cancers of Unknown Primary Origin: Real-World Clinical Outcomes and Genomic Analysis at the European Institute of Oncology.

Cancer of unknown primary origin (CUP) poses a significant challenge due to poor clinical outcomes and limited treatment options. As such, further definition of clinicopathological factors and genomic profile to better adapt treatment strategies is required. Medical records were interrogated to retrospectively include CUP with available clinical and genomics data at the European Institute of Oncology. Next-generation sequencing (NGS) included targeted panels. Statistical analyses were conducted with R Software 4.2.2. A total of 44 patients were included. With a median follow-up of 39.46 months (interquartile range [IQR] 35.98-47.41 months), median PFS (mPFS) to first-line regimen was 3.98 months (95% CI 3.22-5.98), with a clinical benefit rate of 26% (95% CI 14%-49%), and disease control rate (DCR) limited to 48.28%. Most patients (26 of 31, 83.87%) received platinum-doublet chemotherapy, with no statistically significant difference between first-line treatment regimens. Median OS (mOS) was 18.8 months (95% CI 12.3-39.9), with a 12-month OS rate of 66% (95% CI 50%-85%). All patients received comprehensive genomic profiling (CGP). For 11 patients, NGS was unsuccessful due to low sample quantity and/or quality. For the remaining, TP53 (n = 16, 48%) and KRAS (n = 10, 30%) represented the most altered (alt) genes. No microsatellite instability was observed (0 of 28), while 6 of 28 (21.43%) tumors carried high TMB (≥10 mutation per megabase). Eight of 33 tumors (24.2%) displayed at least one actionable alteration with potential clinical benefit according to ESCAT. Only 2 of them received targeted therapy matched to genomic alterations, with a combined mPFS of 2.63 months (95% CI 1.84-not evaluable) as third-line regimens. Six patients received anti-PD1/PD-L1 therapy, showing a meaningful mPFS of 13 months (95% CI 2.04-not evaluable). CUP exhibits poor prognosis with limited benefits from standard treatment regimens. A significant proportion of CUPs carry actionable alterations, underscoring the importance of genomic profiling to gather additional treatment opportunities. In addition, immunotherapy might represent a valuable treatment option for a subset of CUP. Finally, accurate definition of sequencing methods and platforms is crucial to overcome NGS failures.

Abstract 4627: Metastatic renal cell carcinoma with occult primary: Clinical and biological evidence for a new entity of cancers of unknown primary that beneficiates from tissue-tailored treatment

Abstract Background: Cancers of unknown primary (CUP) is a heterogenous group of malignancies characterized by distant metastases in the absence of detectable primary. Specifics subgroups of CUP that share similarities with cancers of known primary beneficiate from tissue-tailored therapeutic strategies. The objective of this study was to characterize the clinical and biological presentation of a cohort of patients with suspected CUP of renal origin (rCUP) and to evaluate their optimal therapeutic management. Methods: All Patients with rCUP identified prospectively between 2020 and 2023 within the French National Multidisciplinary Tumor Board for CUP were included. Centralized pathological review and immunohistochemical stainings were performed. Whole Exome Sequencing (WES), whole transcriptomic sequencing (RNAseq) and application of the deep-learning based algorithm TransCUPtomics for prediction of tissue of origin, and DNA methylation analysis were performed and compared to public renal cell carcinomas (RCC). Progression Free Survival (PFS) and Overall Survival (OS) were calculated using Kaplan-Meier estimates. Results: 23 patients were included. The median age at diagnosis was 57 yo and 17/23 were male. The most common metastatic sites were the bones (N=17) and the lymph nodes (N=14). 19/23 patients presented with at least two distinct distant metastatic sites. Genomic analyses performed in 10 patients led to the identification of recurrent inactivating mutations in genes commonly altered in RCC, including NF2 (N=7), SETD2 (N=3), or VHL (N=1). 10/11 samples analyzed by RNAseq were predicted as RCC by the TransCUPtomics classifier based on their gene expression profiles. DNA methylation profiling performed in 7 samples showed major similarity with known RCC subtypes.Centralized pathological review and integration of molecular characteristics led to the final diagnoses of papillary RCC (N=2), clear cell RCC (N=7), renal medullary carcinoma (N=1), TFEB-amplified RCC (N=1) and unclassified RCC (N=12). 20/23 patients received at least one line of systemic treatment based on the renal origin, including anti-angiogenic TKI, anti-PD1/PDL1 antibody, anti-CTLA4 antibody or mTOR inhibitor. The median PFS under the first renal-oriented systemic treatment was 5 months and 10 patients remained progression-free for more than 6 months under tailored-treatment. The median OS was 31 months, and 11 patients are still alive in October 2023. Conclusions: This study shows that rCUP represent a new entity within CUPs that shares major similarities with classical RCC despite the more frequent presentation of unfavorable prognostic factors. Prolonged survival can be observed with renal-tailored systemic treatment, supporting the individualization of these patients within CUP. Citation Format: Nicolas Jacquin, Julien Masliah-Planchon, Guillaume Grisay, Ronan Flippot, Riwan Brillet, Célia Dupain, Maud Kamal, Isabelle Guillou, Nadège Gruel, Nicolas Servant, Pierre Gestraud, Jennifer Wong, Vincent Cockenpot, Andreia Goncalves, Janick Selves, Hélène Blons, Etienne Rouleau, Oliver Delattre, Christophe Le Tourneau, Ivan Bièche, Yves Allory, Laurence Albigès, Sarah Watson. Metastatic renal cell carcinoma with occult primary: Clinical and biological evidence for a new entity of cancers of unknown primary that beneficiates from tissue-tailored treatment [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 4627.

Abstract 4637: National multidisciplinary tumor board improves diagnostic stratification and therapeutic management in cancers of unknown primary

Abstract Introduction: With the increasing complexity of current diagnostic investigations, the integration of clinical, pathological and genomic characteristics is crucial for the management of patients (pts) with cancers of unknown primary (CUP). A national multidisciplinary tumor board (NatCUPMTB) was created in July 2020 in France to discuss the diagnostic and therapeutic management of CUP pts. The objective of this study was to evaluate the diagnostic, prognostic and therapeutic impact of this NatCUPMTB after 39 months of activity. Methods: This was a multicenter retrospective study with prospective follow-up. All pts discussed at least once in the NatCUPMTB between July 2020 and October 2023 were included. Pts and tumors characteristics, pathological and genomic analyses including WGS, WES and transcriptome analysis performed on the two PFMG2025 (French Genomic Medecine Plan 2025) national sequencing laboratories, multidisciplinary tumor board (MTB) conclusions, and follow-up after MTB were collected. Results: 244 pts were included. The median age at diagnosis was 60 yo, 53% were female, and the majority of patients had an OMS status &amp;lt;2. The median number of metastatic sites at diagnosis was 2, with a majority located in the lymph nodes (62%). The median time between diagnosis and first MTB presentation was 3 months (1-20). At the time of analysis, NatCUPMTB conclusions were available for 129 pts with a second MTB presentation. MTB investigations enabled to identify a likely primary origin in 89/129 (69%) pts, the most frequent being breast carcinoma (N=15), renal carcinoma (N=13) and lung carcinoma (N=13). The most frequently molecular alterations found were in TP53 (37%), KRAS (19%), CDKN2A (18%), NF2 (12%), KMT2C (10%), CDKN2B (9%), PBRM1 (9%) genes. MTB diagnoses were based on the combination of clinical, pathological and genomic investigations in 51/89 (59%) of pts. Importantly, a personalized therapeutic strategy was recommended by NatCUPMTB in 91/129 (71%) of pts. Among these recommendations, 72/91 (79%) were based on the diagnosis of tissue of origin (TOO), 9/91 (10%) on an actionable molecular alteration validated in the TOO indication, 8/91 (9%) on an actionable molecular alteration not validated in the TOO indication and 2/91 (2%) based on a druggable alteration only independently from the TOO. After a median follow-up of 1.5 months, the median overall survival (OS) was 17.7 months from the 2nd MTB presentation. Conclusion: NatCUPMTB provides significant diagnostic in 69% of pts with CUP and a therapeutic strategy recommendation for 71% of pts. Citation Format: Célia Dupain, Nicolas Jacquin, Isabelle Guillou, Etienne Rouleau, Julien Masliah Planchon, Isabelle Soubeyran, Christelle De La Fouchardière, Camille Tlemsani, Hélène Blons, Laëtitia Marisa, Anna Patrikidou, Fabienne Escande, Pierre Blanc, Jennifer Wong, Pierre Saintigny, Sandrine Boyault, Adrien Buisson, Yves Allory, Anne Vincent-Salomon, Vincent Cockenpot, Janick Selves, Ivan Bièche, Maud Kamal, Christophe Le Tourneau, Sarah Watson. National multidisciplinary tumor board improves diagnostic stratification and therapeutic management in cancers of unknown primary [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 4637.

Abstract 4414: Genome-wide DNA methylation classifier diagnoses pancreatic ductal adenocarcinoma in CUP setting

Abstract Introduction: The metastasis of a pancreatic ductal adenocarcinoma (PAAD) is a diagnosis of exclusion and one of the most common causes of cancer of unknown primary (CUP). We have recently developed a genome-wide DNA methylation-based neural network classifier that can accurately differentiate between liver metastasis of a PAAD and intrahepatic cholangiocarcinoma (iCCA) (PAAD-iCCA-Classifier). Therefore, the aim of our study was to test whether our PAAD-iCCA-Classifier can be extended to be used to correctly diagnose PAAD metastases from other sites in CUP setting. Methods: For this purpose, we enhanced the anomaly detection layer of the classifier by incorporating ten mimicker carcinomas to be excluded by this layer. We used a validation set 1 (n=3786) including primary PAAD (n=242), PAAD liver metastases (n=20), iCCA (n=151) and 10 other mimicker carcinomas (n=3373) and a validation set 2 (n=26) including primary PAAD from a real-life clinical cohort from an independent institution to validate the classifier. Next, we tested the classifier on 16 PAAD initially considered CUP samples (test set) from different sites: peritoneum, lung, liver, and lymph node. The clinical history and diagnostic imaging of these samples were used to confirm PAAD as the most probable origin. We further performed differentially methylated probes (DMP) and copy number alterations (CNA) analysis of primary PAAD and metastatic PAAD from different locations. Results: The improved version of the PAAD-iCCA-Classifier achieved an accuracy of 98.43% on the validation set 1 and was able to exclude most of the mimicker carcinomas. On validation set 2, the classifier achieved an accuracy of 88.46%. Medical history, imaging and immunohistochemical analysis of the test set samples confirmed the diagnosis of PAAD. The DNA methylation classifier correctly labeled 15/16 PAAD metastatic samples as PAAD (93.75% accuracy). We observed that the classifier performance was negatively affected by a high CD3+ immune infiltrate and positively affected by high tumor purity and high proliferation rate. CNA revealed that PAAD liver metastases have a distinct CNA profile characterized by chromosome 6, 9 (CDKN2A/B) and 18q (SMAD4) deletions. DMP analysis showed that PAAD liver metastases have global hypomethylation of both promoter- and enhancer-associated CpGs compared to primary PAAD and PAAD peritoneal carcinomatosis. Finally, gene ontology analysis revealed that different epithelial-mesenchymal transition pathways are activated in PAAD liver metastases compared to PAAD peritoneal carcinomatosis. Conclusion: Our tool performs well in classifying metastatic PAAD samples and could be of great clinical use when a PAAD origin is suspected in the case of a CUP. DMP and CNA profiles show that PAAD liver metastases may have a distinct DNA methylation and copy number profile compared to primary and peritoneal carcinomatosis PAAD. Citation Format: Teodor G. Calina, Eilís Perez, Simon Schallenberg, Horst David, Erik Knutsen, David Capper, Mihnea P. Dragomir. Genome-wide DNA methylation classifier diagnoses pancreatic ductal adenocarcinoma in CUP setting [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 4414.

Abstract 6399: Real-world experience of an Asian pan-cancer combined DNA/RNA next generation sequencing (NGS) tissue biopsy assay

Abstract Introduction: Comprehensive molecular profiling with combined DNA-RNA next-generation sequencing (NGS) on tumor tissue is now increasingly being used as standard-of-care for sequence therapy selection to improve cancer survival. Combined DNA-RNA NGS is also considered standard-of-care for central nervous system (CNS) tumor classification. Despite the genetic heterogeneity and diversity of cancers, most commercial combined DNA/RNA NGS assays are validated in Western populations, resulting in knowledge gaps in patient outcomes. We report here for the first time a range of actionable outcomes from a comprehensive DNA/RNA tissue NGS assay designed specifically to probe Asian-prevalent cancers and biomarkers in an international multicenter real-world study in Asia. Methods: 1,002 formalin-fixed paraffin-embedded tissue samples from 995 Asian cancer patients across &amp;gt;70 centers in 7 countries and/or territories underwent real-world DNA/RNA NGS testing in a CAP-accredited CLIA-certified laboratory. Genomic alterations including SNVs, INDELS, gene fusions, CNVs, TMB, and MSI were analyzed using an Asian-centric pan-cancer hybrid-capture NGS panel that comprehensively profiles 572 cancer-related genes and 91 RNA fusion partners (UNITED). Biomarkers were considered actionable if the therapeutic indication in any solid tumor or hematological cancer was FDA-approved, guidelines-recommended, or supported by well-powered phase III clinical trials. Results: 27 cancer types were represented in 1,002 tissue samples, with lung, breast, colorectal, and prostate cancers comprising 45.5% of clinical volume. 79.5% of samples harbored ≥1 actionable biomarker, with the most frequently altered genes being TP53, KRAS, PIK3CA, EGFR, and NF1. Overall, 42.6% of samples had ≥1 biomarker with an indication in the patient’s cancer type, including 81.5% of lung, 59.0% of breast, 61.8% of colorectal, and 42.1% of prostate cancers. Across the pan-cancer cohort, 13.3% was TMB-high and 1.9% was MSI-high. 26.3% of samples were from cancer types outside the original assay design; the top 3 were pancreatic cancer (7.3%), sarcoma (3.3%), and CNS tumor (3.1%). Cancers of unknown primary (CUP) also constituted a significant proportion (3.8%). In CNS tumors, 38.7% harbored an actionable mutation in IDH1, BRAF, or H3-3A. In CUP, 78.8% harbored an actionable mutation; 50% of samples harbored biomarkers that additionally informed potential tumor origin, including mutations in EGFR, MET, ALK, ROS1, and BRCA1. Conclusion: The use of an Asian-focused pan-cancer DNA/RNA NGS panel resulted in detection of actionable biomarkers in 79.5% of clinical cases. These findings support the utility of DNA/RNA NGS assays in informing standard-of-care therapeutic decisions in Asian cancer patients for maximizing cancer survival. Citation Format: Jason Yongsheng Chan, Jing Yi Lee, Zi Yi Wan, Abner Herbert Lim, Tun Kiat Ko, Cedric Chuan-Young Ng, Donald Poon, Jens Samol, Tsz Him So, Su Pin Choo, Ravindran Kanesvaran, Cheng-Vai Hui, Joseph Siu-Kie Au, Aya El Helali, Timothy Yip, Vikneswari Rajasegaran, Sandy Lim, Ruifen Weng, Puay Hoon Tan, Bin Tean Teh, Min-Han Tan, Jonathan Poh. Real-world experience of an Asian pan-cancer combined DNA/RNA next generation sequencing (NGS) tissue biopsy assay [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 6399.

Retrospective analysis of clinical characteristics and outcomes of patients with carcinoma of unknown primary from three tertiary centers in Australia.

Carcinoma of unknown primary (CUP) remains an important tumor entity and a disproportionate cause of cancer mortality. Little is known about the contemporary clinical characteristics, treatment patterns, and outcomes of CUP patients based on updated international classification guidelines. We evaluated a contemporary CUP cohort to provide insight into current clinical practice and the impact of tissue of origin assignment, site-specific and empirical therapy in a real-world setting. We conducted a retrospective cohort study of CUP patients, as defined by the updated European Society of Medical Oncology (ESMO) 2023 guidelines, across three tertiary referral centers in Australia between 2015 and 2022. We analyzed clinical characteristics, treatment patterns, and survival outcomes using the Kaplan-Meier method and Cox regression proportional hazard model between favorable and unfavorable risk groups. We identified a total of 123 CUP patients (n = 86 unfavorable, n = 37 favorable risk as per the 2023 ESMO guidelines). Sixty-four patients (52%) were assigned a tissue of origin by the treating clinician. Median progression free survival (PFS) was 6.8 (95% confidence interval (CI) 5.1-12.1) months and overall survival (OS) 10.2 (95% CI 6.0-18.5) months. Unfavorable risk (hazard ratio [HR] 2.9, p = 0.006), poor performance status (HR 2.8, p < 0.001), and non-squamous histology (HR 2.5, p < 0.05) were associated with poor survival outcome. A total of 70 patients (57%) proceeded to systemic therapy. In patients with non-squamous histology and unfavorable risk, site-specific therapy compared to empirical chemotherapy did not improve outcome (median OS 8.2 vs. 11.8 months, p = 0.7). In this real-world cohort, CUP presentations were heterogenous. Overall survival and rates of systemic treatment were poor. Poor performance status and unfavorable risk were associated with worse survival. For most patients, site-specific therapy did not improve survival outcome. Improved and timely access to diagnostic tests and therapeutics for this group of patients is urgently required.

Advances in Cancer Research: Current and Future Diagnostic and Therapeutic Strategies.

Cancers of unknown primary (CUP) exhibit significant cellular heterogeneity and malignancy, which poses significant challenges for diagnosis and treatment. Recent years have seen deeper insights into the imaging, pathology, and genetic characteristics of CUP, driven by interdisciplinary collaboration and the evolution of diagnostic and therapeutic strategies. However, due to their insidious onset, lack of evidence-based medicine, and limited clinical understanding, diagnosing and treating CUP remain a significant challenge. To inspire more creative and fantastic research, herein, we report and highlight recent advances in the diagnosis and therapeutic strategies of CUP. Specifically, we discuss advanced diagnostic technologies, including 12-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography (18F-FDG PET/CT) or 68Ga-FAPI (fibroblast activation protein inhibitor) PET/CT, liquid biopsy, molecular diagnostics, self-assembling nanotechnology, and artificial intelligence (AI). In particular, the discussion will extend to the effective treatment techniques currently available, such as targeted therapies, immunotherapies, and bio-nanotechnology-based therapeutics. Finally, a novel perspective on the challenges and directions for future CUP diagnostic and therapeutic strategies is discussed.

A case of hereditary breast and ovarian cancer syndrome of initially presented as cancer of unknown primary with lymph node metastases unveiled by genetic analysis

Cancer of unknown primary (CUP) is a heterogeneous disease concept involving various malignant tumors. Understanding its pathophysiology is often difficult, together with its treatment. Here, we present a case of CUP with abdominal lymph node enlargement and elevated carbohydrate antigen 125 levels. It initially resembled a favorable prognosis type similar to ovarian cancer, but metastases were observed in cervical lymph nodes, indicating a somewhat atypical CUP compared to the typical ovarian cancer-like CUP. We identified a germline Breast Cancer 1 (BRCA1) p.L63* variant through a family history inquiry and BRCA analysis, indicating hereditary breast and ovarian cancer syndrome. The patient achieved near-complete remission with platinum-based therapy followed by poly (ADP-ribose) polymerase (PARP) inhibitor. The variant has shown sensitivity in both clinical and pathogenic reports in the ClinVar database of the National Institutes of Health. No clinical studies reported on the efficacy of PARP inhibitors specific to this variant, but our case demonstrated the sensitivity of platinum-based therapy followed by PARP inhibitor. Reports of CUP in hereditary breast and ovarian cancer syndrome are very rare, with only a single report in the literature.

Biomarkers of systemic inflammation provide additional prognostic stratification in cancers of unknown primary.

Biomarkers of systemic inflammation have been shown to predict outcomes in patients with cancer of unknown primary (CUP). We sought to validate these findings in patients with confirmed CUP (cCUP) and explore their role alongside existing clinicopathological prognostic categories. CUP oncologist from across the United Kingdom were invited to include patients with cCUP referred to their local CUP multidisciplinary team. Patient demographics, clinical, pathological and outcome data were recorded and analysed. Data were available for 548 patients from four CUP services. 23% (n = 124) of patients met clinicopathological criteria for favourable-risk cCUP. On multivariate analysis c-reactive protein (CRP) (p < 0.001) and the Scottish Inflammatory Prognostic Score (SIPS: combining albumin and neutrophil count) (p < 0.001) were independently predictive of survival. CRP and SIPS effectively stratified survival in patients with both favourable-risk and poor-risk cCUP based on clinicopathological features. Biomarkers of systemic inflammation are reliable prognostic factors in patients with cCUP, regardless of clinicopathological subgroup. We recommend that CRP or SIPS are incorporated into routine clinical assessments of patients with cCUP as a tool to aid investigation and/or treatment decision-making across all groups. Established clinicopathological factors can then be used to inform management pathways and specific systemic anticancer therapy selection.

Immunohistochemical Expression of SATB2 in Malignant Melanomas.

Accurate diagnosis of cancer of unknown primary (CUP) poses a significant daily challenge for pathologists, necessitating reliable immunohistochemical (IHC) markers. SATB2 is a transcription factor primarily expressed in colorectal neoplasms. This study investigates the IHC expression of SATB2 in malignant melanomas (MM). Using tissue microarrays (TMAs) from Aalborg University Hospital, Denmark, comprising 56 primary and 12 metastatic MMs, we evaluated SATB2 expression through H-scores. We found that 48% of MM cases expressed SATB2, predominantly with weak to moderate staining intensity. Although no significant difference was observed between primary and metastatic MMs, a higher median H-score was noted in metastatic lesions. The results highlight the potential diagnostic pitfall of SATB2 expression in MM and underline the need for careful interpretation.

New techniques to identify the tissue of origin for cancer of unknown primary in the era of precision medicine: progress and challenges.

Despite a standardized diagnostic examination, cancer of unknown primary (CUP) is a rare metastatic malignancy with an unidentified tissue of origin (TOO). Patients diagnosed with CUP are typically treated with empiric chemotherapy, although their prognosis is worse than those with metastatic cancer of a known origin. TOO identification of CUP has been employed in precision medicine, and subsequent site-specific therapy is clinically helpful. For example, molecular profiling, including genomic profiling, gene expression profiling, epigenetics and proteins, has facilitated TOO identification. Moreover, machine learning has improved identification accuracy, and non-invasive methods, such as liquid biopsy and image omics, are gaining momentum. However, the heterogeneity in prediction accuracy, sample requirements and technical fundamentals among the various techniques is noteworthy. Accordingly, we systematically reviewed the development and limitations of novel TOO identification methods, compared their pros and cons and assessed their potential clinical usefulness. Our study may help patients shift from empirical to customized care and improve their prognoses.

Comprehensive genomic profiling of squamous cell carcinoma of unknown primary presenting with liver metastases.

755 Background: Carcinomas of unknown primary (CUPs) are comprised of metastatic cancers for which a primary tumor of origin cannot be identified despite a full diagnostic workup. They frequently present with liver metastases, which portend a poor prognosis. Strategies employing comprehensive genomic profiling (CGP) to identify targeted treatments for CUPs have shown potential. Despite this, the molecular landscape of squamous cell carcinomas of unknown primary (SCCUPs) remains poorly defined. This study describes the results of CGP testing in patients with SCCUPs identified in the Foundation Medicine, Inc. database, with a focus on those with liver involvement. Methods: Cases of SCCUPs with FoundationOne CDx (F1CDx) assay results were identified based on a reported diagnosis of CUP and the presence of SCC histology. Cases then underwent central pathologist review and were excluded if a known primary site could be determined based on histology and disease location. Cases with liver involvement were selected based on the site of tissue biopsy. Genomic analyses of identified cases were assessed using the FoundationCORE database. Results: Sixty-nine cases of SCCUP presenting with liver involvement were identified. Alterations were observed in 102 of 324 (31.5%) genes evaluated by the F1CDx assay in at least 1 patient. The most frequently altered genes were TP53 (66.7%) , CDKN2A (33.3%) , CDKN2B (23.2%) , KRAS (21.7%; 0% G12C) , PIK3CA (18.8%), NFE2L2 (11.6%), SOX2 (11.6%), M2M2 (10.1%), and MTAP (10.1%). No patients had microsatellite instability-high disease, only 6 (8.7%) patients had a tumor mutational burden (TMB) ≥ 10, and 11 (15.9%) patients had evidence of HPV infection. Among 33 patients with available PDL-1 testing results, 7 (21.2%) had high-positive expression. An additional 374 cases of SCCUP were identified with involvement outside of the liver. Compared to these cases, patients presenting with liver involvement had less genomic alterations per tumor (5.10 vs 6.71, p=0.005), and were less likely to have TMB ≥ 10 (8.7% vs 38.0%; odds ratio [OR] 0.16, p&lt;0.001). KRAS mutations were observed in 21.7% of those presenting with liver metastases compared to 8.3% of other SCCUP patients (OR 3.07, p=0.07). Conclusions: SCCUPs presenting with liver metastases had reduced numbers of genomic alterations and decreased TMB compared to other SCCUPs, suggesting these tumors may be less likely to respond to immunotherapy. Despite this, 36.2% of these patients had at least one alteration that could potentially guide targeted treatment decisions including entry into biomarker-driven clinical trials. Interestingly, there was a trend toward increased KRAS alterations in those with liver metastases. To our knowledge, this is the first report that describes the genomic landscape of SCCUPs presenting with liver metastases.

Utility of gene expression–based cancer classification in diagnosis of malignant peritoneal mesothelioma (MPeM): Filling in the gaps in standard pathologic work-up for a rare cancer.

728 Background: Malignant peritoneal mesothelioma (MPeM) is a rare cancer (incidence of 0.12 per 100,000) and an arduous diagnostic challenge, requiring skillful evaluation by expert pathologists. Subjective and experiential immunophenotyping coupled with inattention to this rare entity causes delayed or misdiagnosis and leads to suboptimal treatment and outcomes. Gene-expression-based cancer classification offers an objective molecular assessment of the tissue of origin for cancers with uncertain diagnosis and improves diagnostic accuracy for MPeM compared to standard pathology. Methods: We retrospectively evaluated 23 patients (pts) with cancer of unknown primary (CUP) or uncertain diagnoses, with peritoneal/retroperitoneal carcinomatosis and reported as malignant mesothelioma using a 92-gene assay (CancerTYPE ID), a validated classifier for predicting tumor types, between January 2013 to December 2016. Pathology was verified by central review. Clinicopathologic data including immunohistochemistry (IHC) was collected using archived pathology specimens and reports. Results: Pts had a median age of 64 years (range: 39 – 93) at diagnosis, 57% were females and 74% had biopsy from omentum/peritoneum. Original histopathology was reported as poorly differentiated in 81% and as adenocarcinoma, carcinoma and malignant neoplasm in 10 (43%), 7 (30%) and 6 (27%) of cases, respectively. The number of IHC stains performed ranged between 0 and 28 (median: 10). Key IHC stains are shown in the table. Conclusions: In this cohort of CUP or uncertain diagnoses with a molecular cancer classification of malignant mesothelioma, we found huge variability and critical gaps in pathological work-up. Integration of molecular cancer classification using the 92-gene assay helped resolve this diagnostic uncertainty, further supporting its clinical utility to complement standard pathology. The impact of these findings goes beyond just MPeM and may benefit numerous pts with orphan cancers, who account for nearly 20% of all cancers diagnosed globally. [Table: see text]

Real-world (RW) characteristics, treatment patterns, and outcomes of patients with cholangiocarcinoma (CCA) treated with pemigatinib.

444 Background: Pemigatinib demonstrated efficacy in fibroblast growth factor receptor (FGFR)–altered CCA in the FIGHT-202 trial; however, limited RW evidence exists on treatment patterns and outcomes in patients (pts) with CCA treated with pemigatinib. This study assessed characteristics, FGFR2 testing patterns, treatment patterns, and outcomes of pts treated with pemigatinib for locally advanced or metastatic CCA in the United States as part of routine clinical care. Methods: This retrospective, multisite cohort study included pts with a diagnosis of unresectable locally advanced or metastatic CCA who were initially prescribed pemigatinib on or after 04/17/2020. Eligible pts were ≥18 years at pemigatinib prescription and had ≥4 months (mo) of follow-up (unless &lt;4 mo due to death). Pts who received pemigatinib as part of a clinical trial or those who received systemic therapy for another primary malignancy (other than cancer of unknown primary or hepatic cancer) were ineligible. Participating physicians from Cardinal Health’s Oncology Provider Extended Network—approximately 72% from community oncology practices—abstracted data from the medical records of eligible patients into electronic case report forms. Results were summarized using descriptive statistics. Results: Data from 120 pts (49% male; 55% White; 19% Hispanic; median age at pemigatinib prescription, 65 years) were collected from 18 physicians/practices. Testing for FGFR2 alterations was completed in 93% (n=111) of pts; of those, all but one patient (result unknown) tested positive, and 95% were tested using next-generation sequencing. At time of pemi prescription, 90% of pts had metastatic disease. Across all pts, 94% and 6% were prescribed pemigatinib as 2nd and 3rd line of therapy, respectively. The most common starting dosage was 13.5 mg daily for 14 days of 21-day cycle (87.5% of pts). Among the 60 pts who discontinued pemi during the 6.5-month median study follow-up period, 68% discontinued due to disease progression. Median RW progression-free survival (rwPFS) from date of pemigatinib initiation was 7.4 (95% CI: 6.4–8.6) mo. Among the 116 patients with tumor response data available, RW overall response rate (rwORR) was 61% (95% CI: 52% - 71%). Conclusions: This study complements the FIGHT-202 clinical trial by assessing the use of pemigatinib among a diverse population of patients with CCA under RW conditions. Secondarily, the rwORR and rwPFS from this study support the clinical benefit of pemigatinib demonstrated in FIGHT-202.

Real-world use of pemigatinib (pemi) for cholangiocarcinoma (CCA) among racial and ethnic minorities in the United States.

461 Background: Pemi received accelerated approval by the FDA in 2020 for treatment of patients (pts) with unresectable locally advanced or metastatic CCA with a fibroblast growth factor receptor 2 ( FGFR2) fusion or other FGFR2 rearrangement. A recent real-world study (RWS; submitted to ASCO-GI 2024) assessing characteristics, FGFR2 testing patterns, treatment patterns, and outcomes of pts treated with pemi for locally advanced or metastatic CCA in the US as part of routine clinical care found substantial racial and ethnic diversity in pts treated with pemi. The purpose of this analysis is to describe the findings of the pemi RWS for CCA by race and ethnicity. Methods: This was a retrospective cohort study in which US-based participating physicians from Cardinal Health’s Oncology Provider Extended Network abstracted data from eligible pts’ medical records into electronic case report forms. Eligible pts were ≥18 years of age, initially prescribed pemi for unresectable locally advanced or metastatic CCA on or after 4/17/2020, and had ≥4 mo of follow-up (unless &lt;4 mo due to death). Pts who did not receive pemi or had received pemi in a clinical trial or systemic therapy for another primary malignancy (except for cancer of unknown primary or hepatic cancer) were excluded. Results were summarized by race (White, Black/African American, “Other” [pts with mixed race or a race other than White, Black/African American, or Unknown]) and ethnicity (Non-Hispanic, Hispanic) using descriptive statistics. Results: 18 physicians abstracted data for 120 eligible pts. Median follow-up from initial pemi prescription was 6.5 mo, at which time 71 pts (59%) were alive and 60 (50%) were still receiving pemi. The racial makeup of the study population was 55% White, 21% Black, 18% Other, and 7% Unknown. Ethnic composition was 78% Non-Hispanic, 19% Hispanic, and 3% Unknown. Key results are presented in the Table. Conclusions: The diverse population in this RWS is reflective of the heterogeneous CCA pt population in the US. These real-world overall response rates support the clinical benefit of pemi across racial and ethnic groups and complement the results of the clinical trial. [Table: see text]