Treatment for patients with unknown primary cancer and favorable prognostic factors

Seeing the primary tumor because of all the trees: Cancer type prediction on low-dimensional data

The Cancer of Unknown Primary (CUP) syndrome is characterized by identifiable metastases while the primary tumor remains hidden. In recent years, various data-driven approaches have been suggested to predict the location of the primary tumor (LOP) in CUP patients promising improved diagnosis and outcome. These LOP prediction approaches use high-dimensional input data like images or genetic data. However, leveraging such data is challenging, resource-intensive and therefore a potential translational barrier. Instead of using high-dimensional data, we analyzed the LOP prediction performance of low-dimensional data from routine medical care. With our findings, we show that such low-dimensional routine clinical information suffices as input data for tree-based LOP prediction models. The best model reached a mean Accuracy of 94% and a mean Matthews correlation coefficient (MCC) score of 0.92 in 10-fold nested cross-validation (NCV) when distinguishing four types of cancer. When considering eight types of cancer, this model achieved a mean Accuracy of 85% and a mean MCC score of 0.81. This is comparable to the performance achieved by approaches using high-dimensional input data. Additionally, the distribution pattern of metastases appears to be important information in predicting the LOP.

Revolutionizing Pathology with Artificial Intelligence: Innovations in Immunohistochemistry

Artificial intelligence (AI) is a reality of our times, and it has been successfully implemented in all fields, including medicine. As a relatively new domain, all efforts are directed towards creating algorithms applicable in most medical specialties. Pathology, as one of the most important areas of interest for precision medicine, has received significant attention in the development and implementation of AI algorithms. This focus is especially important for achieving accurate diagnoses. Moreover, immunohistochemistry (IHC) serves as a complementary diagnostic tool in pathology. It can be further augmented through the application of deep learning (DL) and machine learning (ML) algorithms for assessing and analyzing immunohistochemical markers. Such advancements can aid in delineating targeted therapeutic approaches and prognostic stratification. This article explores the applications and integration of various AI software programs and platforms used in immunohistochemical analysis. It concludes by highlighting the application of these technologies to pathologies such as breast, prostate, lung, melanocytic proliferations, and hematologic conditions. Additionally, it underscores the necessity for further innovative diagnostic algorithms to assist physicians in the diagnostic process.

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.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

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

BACKGROUND

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.

PATIENTS AND METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Significance of Distinct Liquid Biopsy Compartments in Evaluating Somatic Mutations for Targeted Therapy Selection in Cancer of Unknown Primary

PURPOSE

Cancer of unknown primary (CUP) accounts for 2-5% of all cancer diagnoses, wherein standard investigations fail to reveal the original tumor site. Basket trials allocate targeted therapeutics based on actionable somatic mutations, independent of tumor entity. These trials, however, mostly rely on variants identified in tissue biopsies. Since liquid biopsies (LB) represent the overall tumor genomic landscape, they may provide an ideal diagnostic source in CUP patients. To identify the most informative liquid biopsy compartment, we compared the utility of genomic variant analysis for therapy stratification in two LB compartments (circulating cell-free (cf) and extracellular vesicle (ev) DNA).

METHODS

CfDNA and evDNA from 23 CUP patients were analyzed using a targeted gene panel covering 151 genes. Identified genetic variants were interpreted regarding diagnostic and therapeutic relevance using the MetaKB knowledgebase.

RESULTS

LB revealed a total of 22 somatic mutations in evDNA and/or cfDNA in 11/23 patients. Out of the 22 identified somatic variants, 14 are classified as Tier I druggable somatic variants. Comparison of variants identified in evDNA and cfDNA revealed an overlap of 58% of somatic variants in both LB compartments, whereas over 40% of variants were only found in one or the other compartment.

CONCLUSION

We observed substantial overlap between somatic variants identified in evDNA and cfDNA of CUP patients. Nonetheless, interrogation of both LB compartments can potentially increase the rate of druggable alterations, stressing the significance of liquid biopsies for possible primary-independent basket and umbrella trial inclusion.

[Radiological imaging in CUP syndrome]

PROBLEM

If no obvious primary tumour is detectable in metastatic tumours (cancer of unknown primary, CUP), it should nevertheless be identified if possible, as specific therapy achieves better results than empirical, palliative treatment of CUP.

METHODOLOGY

The new guideline of the European Society of Medical Oncology (ESMO) defines algorithms for the evaluation of CUP, in which radiological and nuclear imaging procedures play a central role. Important clues to a possible primary tumour are the size and morphology of foci and the presence of a dominant lesion, as well as the pattern of hematogeneous metastatic spread in affected organs, and the anatomical distribution of affected lymph nodes.

CONCLUSION

In patients with metastases, imaging plays an important role in identifying a possible primary tumour, but the diagnosis must be made with knowledge of the clinical and immunohistochemical results. In difficult cases, there should be interdisciplinary consultation between reference oncology, radiology, and pathology on the presence of CUP.

Cancer of unknown primary site in the mandibular region: A case report

The diagnosis and treatment of cancer of unknown primary site (CUP) present with difficulties and produce a poor prognosis. The current study presents the case of a patient with CUP in the mandibular region was treated with docetaxel and lobaplatin chemotherapy, and vascular embolization of the tumor. The tumor size was markedly reduced and the patient's quality of life improved following radiotherapy. The present case report is accompanied by a discussion of the literature to contextualize the treatment regimen for patients with CUP. These findings will support current treatment practices, inform oncologists and benefit patients with cancer.

Intrahepatic cholangiocarcinoma hidden within cancer of unknown primary

Background

Many patients referred with a provisional diagnosis of cancer of unknown primary (pCUP) present with presumed metastatic disease to the liver. Due to the lack of definitive histological markers, intrahepatic cholangiocarcinoma (iCCA) may be overlooked. This study assessed the frequency of iCCA within a pCUP cohort.

Methods

A single UK cancer-center study of sequential patients referred with pCUP from January 2017 to April 2020. Baseline diagnostic imaging was reviewed independently by a radiologist and oncologist; those with radiological features of iCCA (dominant liver lesion, capsular retraction) were identified.

Results

Of 228 patients referred with pCUP, 72 (32%) had malignancy involving the liver. 24/72 patients had radiological features consistent with iCCA; they were predominantly female (75%) with an average age of 63 years and 63% had an ECOG PS ≤ 2. The median overall survival (OS) of the iCCA group and the remaining liver-involved CUP group were similar (OS 4.1 vs 4.4 months, p-value = 0.805). Patients, where a primary diagnosis was subsequently determined, had better OS (10.2 months, p-values: iCCA = 0.0279: cCUP = 0.0230).

Conclusions

In this study, 34% of patients with liver-involved pCUP, fulfilled the radiological criteria for an iCCA diagnosis. Consideration of an iCCA diagnosis in patients with CUP could improve timely diagnosis, molecular characterisation and treatment.

SEOM-GECOD clinical guideline for unknown primary cancer (2021)

Cancer of unknown primary site (CUP) is defined as a heterogeneous group of tumors that appear as metastases, and of which standard diagnostic work-up fails to identify the origin. It is considered a separate entity with a specific biology, and nowadays molecular characteristics and the determination of actionable mutations may be important in a significant group of patients. In this guide, we summarize the diagnostic, therapeutic, and possible new developments in molecular medicine that may help us in the management of this unique disease entity.

Local ablative treatment with surgery and/or radiotherapy in single-site and oligometastatic carcinoma of unknown primary

BACKGROUND

Single-site carcinoma of unknown primary (CUP) is recognised as a distinct favourable subtype in the European Society of Medical Oncology (ESMO) classification. There is broad consensus that these patients are candidates for local ablative treatment strategies with surgery and/or radiotherapy, but data on their outcomes are scarce.

PATIENTS AND METHODS

In this study, we have addressed the prospects of cure and prognostic factors in a retrospective cohort of 63 patients who were eligible for local treatment at our centre.

RESULTS

Median event-free (EFS) and overall survival (OS) were 15.6 months and 52.5 months, respectively. Of 61 patients who received local treatment, 20 (32.8%) remained event-free over a median follow-up of 28 months. Baseline clinical parameters including affected organ, number, volume and histology of metastases had no significant impact on prognosis, whereas deleterious TP53 mutations and DNA copy number loss emerged as independent adverse risk factors with respect to EFS. Surgical treatment was associated with improved OS as compared to radiation-based therapy.

CONCLUSION

Our study advocates to pursue localised treatment with surgery and/or radiotherapy whenever feasible and implies that genetic parameters might additionally determine the clinical course of single-site CUP patients.

Characterisation and outcomes of patients referred to a regional cancer of unknown primary team: a 10-year analysis

BACKGROUND

In the United Kingdom, national guidance published in 2010 recommended the establishment of specialist teams to improve clinical pathways for patients presenting with malignancies of undefined primary origin (MUO) and cancer of unknown primary (CUP). This study sought to define outcomes of patients referred to a regional MUO/CUP service.

METHODS

Data were collected prospectively on all patients (n = 1225) referred to a regional CUP team over a 10-year period. Patient demographics, clinical, pathological and outcome data were recorded and analysed.

RESULTS

Confirmed CUP (cCUP) was diagnosed in 25% of patients. A primary metastatic cancer was identified in 36%, 5% were diagnosed with provisional CUP (pCUP), 27% retained the diagnosis of MUO and in 8% a non-cancer diagnosis was made. Median survival was low in all patients with a final malignant diagnosis: primary identified 9.0 months, cCUP 4.0 months, pCUP 1.5 months and MUO 1.5 months.

CONCLUSIONS

Patients presenting with MUO have poor outcomes irrespective of the final diagnosis. These patients need a patient-centred, streamlined, rapid diagnostic pathway. There are clear benefits to primary and secondary care teams having access to a dedicated, multidisciplinary MUO/CUP service, with clinical nurse specialists supporting the patients, to help facilitate this pathway and ensure early oncology review.

A Case Report of Squamous Cell Carcinoma of Unknown Primary That Metastasized to an Inguinal Lymph Node

The term carcinoma of unknown primary (CUP) refers to a malignant tumor whose histology suggests strongly that it is a metastasis, yet the primary lesion is unknown despite sufficient whole body evaluation at the time of examination. CUP has similar incidences in men and women and the average age at diagnosis is 60 years. While its overall incidence varies depending on the report, it generally accounts for 1-5% of all cancers. Thus, it is rare. We encountered a case of squamous cell carcinoma of the inguinal region that seemed to be a metastasis and for which we could not find the primary lesion. This case is reported here along with a literature review on CUP to increase awareness of this rare lesion.

Emerging noninvasive methylation biomarkers of cancer prognosis and drug response prediction

Cancer is the second leading cause of death worldwide being responsible for 9.6 million deaths in 2018. Epigenetic alterations are key in directing the aberrant expression of tumor-associated genes that drive cellular malignant transformation and cancer progression. Among epigenetic alterations, DNA methylation is the most deeply studied one in relation to environmental exposure. Tissue biopsies have traditionally been the main procedure by which a small sample of body tissue is excised to confirm cancer diagnosis or to indicate the primary site when cancer has spread. In contrast, the analysis of circulating tumor-derived material, or tumor circulome, by means of liquid biopsy of peripheral blood, urine, saliva or sputum is a noninvasive, fast and reproducible alternative to tissue biopsy. Recently, the assessment of epigenetic alterations such as DNA methylation and hydroxymethylation in circulating free DNA has been proved possible. These marks can be associated to prognosis and response to a variety of treatments including chemotherapy, hormonotherapy or immunotherapy. Epigenetic biomarkers may offer some advantages over RNA or genetic biomarkers given their stability in bodily fluids and their high tissue-specificity. While many challenges are still ahead, the unique advantages of these types of biomarkers is urging the scientific community to persevere in their clinical validation and integration into reliable prediction models. This review aims at recapitulating the emerging noninvasive DNA methylated biomarkers of importance for prediction of prognosis and drug response in cancer.

Cancer of Unknown Primary: Challenges and Progress in Clinical Management

Distant metastases are the main cause of cancer-related deaths in patients with advanced tumors. A standard diagnostic workup usually contains the identification of the tissue-of-origin of metastatic tumors, although under certain circumstances, it remains elusive. This disease setting is defined as cancer of unknown primary (CUP). Accounting for approximately 3-5% of all cancer diagnoses, CUPs are characterized by an aggressive clinical behavior and represent a real therapeutic challenge. The lack of determination of a tissue of origin precludes CUP patients from specific evidence-based therapeutic options or access to clinical trial, which significantly impacts their life expectancy. In the era of precision medicine, it is essential to characterize CUP molecular features, including the expression profile of non-coding RNAs, to improve our understanding of CUP biology and identify novel therapeutic strategies. This review article sheds light on this enigmatic disease by summarizing the current knowledge on CUPs focusing on recent discoveries and emerging diagnostic strategies.

Evaluation of the mir-126, mir-182, and mir-486-5p Expression Signature of Head and Neck Squamous Cell Carcinomas and Lung Squamous Cell Carcinomas

OBJECTIVE

Although squamous cell carcinomas (SCCs) originating from different anatomic localizations display a similar histological appearance under light microscopy, they may differ in terms of epigenetic and genetic features. The aim of this study was to analyze mir-126, mir-182, and mir-486-5p expression levels in head and neck SCCs and lung SCCs, and to identify localization-specific miRNA expression profiles.

MATERIAL AND METHOD

The expression levels of mir-126, mir-182, and mir-486-5p were analyzed in lung, oral cavity, laryngeal, and hypopharyngeal SCCs in 40 patients, using quantitative real-time polymerase chain reaction.

RESULTS

The findings showed that lung, oral cavity, laryngeal, and hypopharyngeal SCCs have distinct mir-126 and mir-486-5p expression profiles. It was also observed that mir-126 and mir-486-5p expression levels were highly specific to the tumor localization.

CONCLUSION

These findings highlighted that SCCs originating from different anatomic localizations have different miRNA expression profiles. miRNA expression analysis can be used to predict the primary localizations of those SCCs.

Cancer of unknown primary

Cancers of unknown primary (CUPs) are histologically confirmed, metastatic malignancies with a primary tumor site that is unidentifiable on the basis of standard evaluation and imaging studies. CUP comprises 2-5% of all diagnosed cancers worldwide and is characterized by early and aggressive metastasis. Current standard evaluation of CUP requires histopathologic evaluation and identification of favorable risk subtypes that can be more definitively treated or have superior outcomes. Current standard treatment of the unfavorable risk subtype requires assessment of prognosis and consideration of empiric chemotherapy. The use of molecular tissue of origin tests to identify the likely primary tumor site has been extensively studied, and here we review the rationale and the evidence for and against the use of such tests in the assessment of CUPs. The expanding use of next generation sequencing in advanced cancers offers the potential to identify a subgroup of patients who have actionable genomic aberrations and may allow for further personalization of therapy.

Lung-Seeking Metastases

Metastases from different cancer types most often affect the lung parenchyma. Moreover, the lungs are among the most frequent sites of growth of metastatic masses of uncertain/unknown lineage of origin. Thus, with regards to pulmonary neoplastic parenchymal nodules, the critical issue is to determine if they are IN the lung or OF the lung. In this review, we highlight the clinical, instrumental and molecular features which characterize lung metastases, mainly focusing on recently advancing and emerging concepts regarding the metastatic niche, inflammation, angiogenesis, immune modulation and gene expression. A novel issue is related to the analysis of biomechanical forces which cooperate in the expansion of tumor masses in the lungs. We here aim to analyze the biological, genetic and pathological features of metastatic lesions to the lungs, here referred to as site of metastatic growth. This point should be a crucial part of the algorithm for a proper diagnostic and therapeutic approach in the era of personalized medicine.

Molecular characterisation and liquid biomarkers in Carcinoma of Unknown Primary (CUP): taking the 'U' out of 'CUP'

Cancers of Unknown Primary (CUP) comprise a heterogeneous clinical entity of confirmed metastatic cancer where the primary site of origin is undetectable. It has a poor prognosis with limited treatment options. CUP is historically under-researched; however, understanding its biology has the potential to not only improve treatment and survival by implementation of biomarkers for patient management, but also to greatly contribute to our understanding of carcinogenesis and metastasis across all cancer types. Here we review the current advances in CUP research and explore the debated hypotheses underlying its biology. The evolution of molecular profiling and tissue-of-origin classifiers have the potential to transform the diagnosis, classification and therapeutic management of patients with CUP but robust evidence to support widespread use is lacking. Precision medicine has transformed treatment strategy in known tumour types; in CUP, however, there remains a clinical need for a better understanding of molecular characteristics to establish the potential role of novel or existing therapeutics. The emergence of liquid biopsies as a source of predictive and prognostic biomarkers within known tumour types is gaining rapid ground and this review explores the potential utility of liquid biopsies in CUP.

[2018 Consensus statement by the Spanish Society of Pathology and the Spanish Society of Medical Oncology on the diagnosis and treatment of cancer of unknown primary]

Cancer of unknown primary is defined as a heterogeneous group of tumours that present with metastasis, and in which attempts to identify the original site have failed. They differ from other primary tumours in their biological features and how they spread, which means they can be considered a separate entity. There are several hypotheses regarding their origin, but the most plausible explanation for their aggressiveness and chemoresistance seems to involve chromosomal instability. Depending on the type of study done, cancer of unknown primary can account for 2-9% of all cancer patients, mostly 60-75 years old. This article reviews the main clinical, pathological and molecular studies conducted to analyse and determine the origin of cancer of unknown primary. The main strategies for patient management and treatment, by both clinicians and pathologists, are also addressed.

2018 consensus statement by the Spanish Society of Pathology and the Spanish Society of Medical Oncology on the diagnosis and treatment of cancer of unknown primary

Cancer of unknown primary (CUP) is defined as a heterogeneous group of tumours that present with metastasis, and in which attempts to identify the original site have failed. They differ from other primary tumours in their biological features and how they spread, which means that they can be considered a separate entity. There are several hypotheses regarding their origin, but the most plausible explanation for their aggressiveness and chemoresistance seems to involve chromosomal instability. Depending on the type of study done, CUP can account for 2–9% of all cancer patients, mostly 60–75 years old. This article reviews the main clinical, pathological, and molecular studies conducted to analyse and determine the origin of CUP. The main strategies for patient management and treatment, by both clinicians and pathologists, are also addressed.

Molecular driver alterations and their clinical relevance in cancer of unknown primary site

Cancer of unknown primary (CUP) is defined as metastatic solid malignancy where no primary tumor is detected despite appropriate staging. About 90% of CUP represent adenocarcinoma or undifferentiated carcinoma. Since therapy regimens are only modestly effective, identification of the molecular landscape of these neoplasms might be a promising approach to direct CUP therapy and aid in tumor classification. We screened a cohort of 128 patients with adenocarcinoma or undifferentiated carcinoma meeting the definition of CUP. Massive parallel multigene sequencing of 50 genes, which had been selected due to their relevance as oncogenic drivers or druggable molecular targets could ultimately be performed on samples from 55 patients for whom complete clinical datasets were also available. Overall, 60 tumor-specific mutations and 29 amplifications/deletions, as revealed by coverage analysis, were detected in 46 cases (84%). The most frequently mutated genes were TP53 (30 cases, 55%), KRAS (9 cases, 16%), CDKN2A (5 cases, 9%), and SMAD4 (5 cases, 9%). The most frequently deleted gene was CDKN2A (8 cases, 15%). KRAS and CDKN2A mutations significantly correlated with poor progression-free survival (PFS) and, in case of KRAS, overall survival (OS). WIldtype TP53 and female sex defined a relatively favorable category, with favorable PFS and OS. 8 cases (15%) harbored mutations that may be targetable by currently approved drugs. Taken together, Mutations of relevant driver genes are present in the vast majority of CUP tumors. Some of them impact on prognosis and a subset is putatively druggable.

SEOM clinical guideline on unknown primary cancer (2017)

Cancer of unknown primary site is a histologically confirmed cancer that manifests in advanced stage, with no identifiable primary site following standard diagnostic procedures. Patients are initially categorized based on the findings of the initial biopsy: adenocarcinoma, squamous-cell carcinoma, neuroendocrine carcinoma, and poorly differentiated carcinoma. Appropriate patient management requires understanding several clinical and pathological features that aid in identifying several subsets of patients with more responsive tumors.

Diagnosis and management of metastatic neoplasms with unknown primary

In cancer of unknown primary (CUP), metastases are clinically and histologically confirmed, but the primary tumor site remains elusive after extensive work-up. CUPs make up for 2-3% of all epithelial malignancies. The two prevailing histologies are adenocarcinomas and undifferentiated carcinomas, whereas squamous cell carcinomas, neuroendocrine carcinomas and rare histologies account for the remaining 10%. The diagnostic work-up in CUP relies strongly on a detailed immunohistological (IHC) analysis in order to characterize the tumor type, nowadays aided by molecular techniques. Diagnostics also include a thorough clinical examination, a basic lab draw with the most relevant tumor markers, and cross sectional imaging. Additional PET-CT is recommended in cervical lymph nodes suggestive of head and neck cancer and in limited metastases potentially treatable in curative intent. As for treatment, it is paramount to identify patients who fall into one of the six well defined "favorable" subset categories, namely extragonadal germ cell tumors, adenocarcinoma with isolated unilateral axillary lymph nodes in female patients, squamous cell carcinoma with neck lymph nodes, squamous cell carcinoma with inguinal lymph nodes, serous papillary peritoneal carcinomatosis in females and blastic bone metastasis in males with elevated PSA. These subsets are distinct both regarding the required treatment and the comparably favorable prognosis. Within the remaining "unfavorable" group, patients of colon and renal cancer type should be identified based on IHC and clinical picture, since the prognosis of these patients seems to improve with the use of therapy tailored to the presumed primary as well. For the few patients with limited metastases it should be assessed whether they are candidates for surgery, radiotherapy or surgery followed by irradiation in curative intent. The remaining majority of patients are treated with empiric palliative chemotherapy, typically a platinum - paclitaxel combination, though the level of evidence for this therapy recommendation is low. Gemcitabine alone or in combination can be used as an alternative. Decoding of the molecular profiles in CUP offers the prospect of targeted therapy with novel agents. However, there appears to be no uniform molecular pattern for CUP, and the observed molecular diversity thus poses a challenge to respective clinical trials.

MET Activation and Physical Dynamics of the Metastatic Process: The Paradigm of Cancers of Unknown Primary Origin

The molecular and cellular mechanisms which drive metastatic spread are the topic of constant debate and scientific research due to the potential implications for cancer patients' prognosis. In addition to genetics and environmental factors, mechanics of single cells and physical interaction with the surrounding environment play relevant role in defining invasive phenotype. Reconstructing the physical properties of metastatic clones may help to clarify still open issues in disease progression as well as to lead to new diagnostic and therapeutic approaches. In this perspective cancer of unknown primary origin (CUP) identify the ideal model to study physical interactions and forces involved in the metastatic process. We have previously demonstrated that MET oncogene is mutated with unexpected high frequency in CUPs. We here analyze and discuss how the MET activation by somatic mutation may affect physical properties in giving rise to such a highly malignant syndrome, as that defined by CUP.

Precision medicine based on epigenomics: the paradigm of carcinoma of unknown primary

Epigenetic alterations are a common hallmark of human cancer. Single epigenetic markers are starting to be incorporated into clinical practice; however, the translational use of these biomarkers has not been validated at the 'omics' level. The identification of the tissue of origin in patients with cancer of unknown primary (CUP) is an example of how epigenomics can be incorporated in clinical settings, addressing an unmet need in the diagnostic and clinical management of these patients. Despite the great diagnostic advances made in the past decade, the use of traditional diagnostic procedures only enables the tissue of origin to be determined in ∼30% of patients with CUP. Thus, development of molecularly guided diagnostic strategies has emerged to complement traditional procedures, thereby improving the clinical management of patients with CUP. In this Review, we present the latest data on strategies using epigenetics and other molecular biomarkers to guide therapeutic decisions involving patients with CUP, and we highlight areas warranting further research to engage the medical community in this unmet need.

Next generation sequencing of carcinoma of unknown primary reveals novel combinatorial strategies in a heterogeneous mutational landscape

BACKGROUND

Advanced carcinoma of unknown primary (CUP) has limited effective therapeutic options given the phenotypic and genotypic diversity. To identify future novel therapeutic strategies we conducted an exploratory analysis of next-generation sequencing (NGS) of relapsed, refractory CUP.

METHODS

We identified patients in our phase I clinic where archival tissue was available for a targeted NGS CLIA-certified assay.

RESULTS

Of 17 patients tested, 15 (88%) demonstrated genomic alterations (median 2 aberrations; range 0-8, total 59 alterations). Nine (53%) patients had altered cell signaling including the PI3K/AKT/MTOR (n=5, 29%) and MAPK pathways (n=3,18%); 7 (41%) patients demonstrated ≥1 alterations in tumor suppressor genes (TP53 in 5 patients), 8 (47%) had impaired epigenetic regulation and DNA methylation, 8 (47%) had aberrant cell cycle regulation, commonly in the cyclin dependent kinases. Ten (59%) patients had alterations in transcriptional regulators. Concurrent mutations affecting cell cycle regulation were noted to occur with aberrant epigenetic regulation (n=6, 35%) and MAPK/PI3K pathway (n=5, 29%).

CONCLUSION

Every patient had a unique molecular profile with no two patients demonstrating an identical panel of mutations. We identify two emerging novel combinatorial strategies targeting impaired cell cycle arrest, first with epigenetic modifiers and, second, with MAPK/PI3K pathway inhibition.

Clinical Outcomes in Patients with Cancer of Unknown Primary Site Treated By Gastrointestinal Oncologists

OBJECTIVE

To evaluate the clinical outcomes in patients with cancer of an unknown primary site (CUP), who were treated by gastrointestinal oncologists.

METHODS

We retrospectively studied 29 patients with CUP who were presented at the Department of Gastroenterology, Kitasato University Hospital from October 2005 to October 2013, and were treated by the gastrointestinal oncologists. The patients were divided into two groups, namely chemotherapy group and symptomatic therapy group, and the clinical characteristics and survival times were compared. The clinical course was studied according to the histologic type (adenocarcinoma or non-adenocarcinoma), prognostic subset (favorable or unfavorable), and the presence or absence of chemotherapy.

RESULTS

The chemotherapy group comprised 19 patients, and the symptomatic therapy group comprised 10 patients. The median survival time was 11 months in the chemotherapy group and 3 months in the symptomatic therapy group. Twenty-two patients had adenocarcinoma, and 7 had non-adenocarcinoma. Of the 22 patients with adenocarcinoma, 2 belonged to the favorable prognostic subset and received chemotherapy. One of these patients died of cancer at 47 months, and the other was alive and disease free at 58 months. Among the 20 patients with adenocarcinoma in the unfavorable prognostic subset, 16 received chemotherapy and had a median survival of 16 months. Seven (44%) of these patients survived for at least 21 months, and 3 patients who could receive 3 or more regimens survived for at least 46 months.

CONCLUSION

It might be appropriate for gastrointestinal oncologists to treat CUP on the basis of clinical experience, depending on the situation.

Identification and survival outcomes of a cohort of patients with cancer of unknown primary in Ontario, Canada

BACKGROUND

Cancer of unknown primary origin (CUP) is defined by the presence of pathologically identified metastatic disease without clinical or radiological evidence of a primary tumour. Our objective was to identify incident cases of CUP in Ontario, Canada, and determine the influence of histology and sites of metastases on overall survival (OS).

MATERIAL AND METHODS

We used the Ontario Cancer Registry (OCR) and the Same-Day Surgery and Discharge Abstract Database (SDS/DAD) to identify patients diagnosed with CUP in Ontario between 1 January 2000, and 31 December 2005. Patient diagnostic information, including histology and survival data, was obtained from the OCR. We cross-validated CUP diagnosis and obtained additional information about metastasis through data linkage with the SDS/DAD database. OS was assessed using Cox regression models adjusting for histology and sites of metastases.

RESULTS

We identified 3564 patients diagnosed with CUP. Patients without histologically confirmed disease (n = 1821) had a one-year OS of 10.9%, whereas patients with confirmed histology (n = 1743) had a one-year OS of 15.6%. The most common metastatic sites were in the respiratory or digestive systems (n = 1603), and the most common histology was adenocarcinoma (n = 939). Three-year survival rates were 3.5%, 5.3%, 41.6% and 3.6% among adenocarcinoma, unspecified carcinoma, squamous cell carcinoma and undifferentiated histology, respectively. Three-year survival rates were 40%, 2.4%, 8.0% and 4.6% among patients with metastases localised to lymph nodes, the respiratory or digestive systems, other specified sites, and unspecified sites, respectively.

CONCLUSION

CUP patients in Ontario have a poor prognosis. Some subgroups may have better survival rates, such as patients with metastases localised to lymph nodes and patients with squamous cell histology.

Aggressive Surgical Management for Metastatic Liver Tumors From Squamous Cell Carcinomas: Report of Three Cases

The use of hepatectomy for the treatment of metastatic liver tumors (MLTs) arising from squamous cell carcinomas (SCCs) has not been well investigated. The use of hepatectomy for MLTs from SCCs, especially in advanced cases, needs further investigation. Three patients with SCC-derived MLTs underwent hepatectomy. On clinicopathologic examination, the primary lesions were found to be oral cancer, lung cancer, and oropharyngeal cancer, with synchronous metastasis in 2 patients and metachronous metastasis in 1 patient. One case also involved adrenal metastasis, and another involved direct invasion of the diaphragm and lung. In all cases, surgery was performed to eliminate any residual tumor tissue. After the hepatectomy, 1 patient died (22 months postoperatively) of an unrelated disease, 1 remains alive (30 months postoperatively) with a recurrent tumor, and 1 remains alive (60 months postoperatively) without recurrence. For the patients with solitary MLT derived from SCC, hepatectomy gives a chance for a cure. Thus, aggressive hepatectomy is an important modality in the multidisciplinary approach for controlling SCC-derived MLTs.

Cancer of unknown primary sites: what radiologists need to know and what oncologists want to know

OBJECTIVE

In this article, we review the role of imaging in cancer of unknown primary site (CUP) diagnosis and management and the utility of immunohistochemistry, serum tumor markers, and molecular profiling in the optimized care of CUP patients.

CONCLUSION

With advances in imaging, pathology, and molecular medicine, the diagnosis and management of CUP have evolved into more personalized and site-specific therapies. A multidisciplinary integrated approach among oncologists, pathologists, and radiologists is extremely important.

A prospective comparison of 18F-FDG PET/CT and CT as diagnostic tools to identify the primary tumor site in patients with extracervical carcinoma of unknown primary site

BACKGROUND

The aim of the present study was to evaluate prospectively the diagnostic value of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) and conventional CT regarding the ability to detect the primary tumor site in patients with extracervical metastases from carcinoma of unknown primary (CUP) site.

PATIENTS AND METHODS

From January 2006 to December 2010, 136 newly diagnosed CUP patients with extracervical metastases underwent (18)F-FDG PET/CT. A standard of reference (SR) was established by a multidisciplinary team to ensure that the same set of criteria were used for classification of patients, that is, either as CUP patients or patients with a suggested primary tumor site. The independently obtained suggestions of primary tumor sites using PET/CT and CT were correlated with the SR to reach a consensus regarding true-positive (TP), true-negative, false-negative, and false-positive results.

RESULTS

SR identified a primary tumor site in 66 CUP patients (48.9%). PET/CT identified 38 TP primary tumor sites and CT identified 43 TP primary tumor sites. No statistically significant differences were observed between (18)F-FDG PET/CT and CT alone in regard to sensitivity, specificity, and accuracy.

CONCLUSION

In the general CUP population with multiple extracervical metastases (18)F-FDG PET/CT does not represent a clear diagnostic advantage over CT alone regarding the ability to detect the primary tumor site.

Carcinoma of unknown primary: key radiological issues from the recent National Institute for Health and Clinical Excellence guidelines

Carcinoma of unknown primary origin (CUP) accounts for 3-5% of cancer cases and is the fourth most common cause of cancer death in the UK. CUP management is challenging, partly owing to the heterogeneity of the condition and its presentation, but also owing to the lack of dedicated clinical services for these patients. The recent National Institute for Health and Clinical Excellence (NICE) guidelines on metastatic malignancy of unknown primary origin were developed to improve the co-ordination of diagnostic and clinical services at hospitals treating cancer patients in England and Wales, in particular by the setting up of CUP teams to manage these patients. Radiologists have a vital role in the diagnosis of these patients and should work closely with the CUP team to streamline the diagnostic pathway. This article summarises areas of the NICE guidelines relevant to radiology and discusses the radiological management of patients with CUP, including initial investigation, the importance of biopsy, the management of specific presentations, special investigations and organisational issues.

Cancer of unknown primary site

Cancer of unknown primary site (CUP) is a well recognised clinical disorder, accounting for 3-5% of all malignant epithelial tumours. CUP is clinically characterised as an aggressive disease with early dissemination. Diagnostic approaches to identify the primary site include detailed histopathological examination with specific immunohistochemistry and radiological assessment. Gene-profiling microarray diagnosis has high sensitivity, but further prospective study is necessary to establish whether patients' outcomes are improved by its clinical use. Metastatic adenocarcinoma is the most common CUP histopathology (80%). CUP patients are divided into subsets of favourable (20%) and unfavourable (80%) prognosis. Favourable subsets are mostly given locoregional treatment or systemic platinum-based chemotherapy. Responses and survival are similar to those of patients with relevant known primary tumours. Patients in unfavourable subsets are treated with empirical chemotherapy based on combination regimens of platinum or taxane, but responses and survival are generally poor.

Role of definitive radiation therapy in carcinoma of unknown primary in the abdomen and pelvis

OBJECTIVES

Carcinoma of unknown primary (CUP) in the abdomen and pelvis is a heterogeneous group of cancers with no standard treatment. Considered by many to be incurable, these patients are often treated with chemotherapy alone. In this study, we determined the effectiveness of radiation therapy in combination with chemotherapy in patients with CUP in the abdomen and pelvis.

PATIENTS AND METHODS

Medical records were reviewed for 37 patients with CUP treated with radiation therapy for disease located in the soft tissues and/or nodal basins of the abdomen and pelvis at the University of Texas M.D. Anderson Cancer between 2002 and 2009. All patients underwent chemotherapy, either before or concurrent with radiation therapy. Patients were selected for radiation therapy on the basis of histologic type, disease extent, and prior therapy response. Twenty patients underwent definitive radiation therapy (defined as radiation therapy targeting all known disease sites with at least 45 Gy) and 17 patients underwent palliative radiation therapy. Only 6 patients had surgical resection of their disease. Patient and treatment characteristics were extracted and the endpoints of local disease control, progression-free survival (PFS), overall survival (OS), and treatment-related toxicity incidence were analyzed.

RESULTS

The 2-year PFS and OS rates for the entire cohort were 32% and 57%, respectively. However, in patients treated with definitive radiation therapy, the rates were 48% and 76%, and 7 patients lived more than 3 years after treatment with no evidence of disease progression. Nevertheless, radiation-associated toxicity was significant in this cohort, as 40% experienced Grade 2 or higher late toxicities.

CONCLUSIONS

The use of definitive radiation therapy should be considered in selected patients with CUP in the soft tissues or nodal basins of the abdomen and pelvis.

Complete biologic response to taxane based chemotherapy confirmed by [F]FDG PET/CT and surgery in a cancer of unknown primary site

Cancers of an unknown primary site are heterogenous with respect to their clinical and pathologic features. They are generally very aggressive, but specific favorable subsets have a better prognosis. For these favorable subsets, taxane based chemotherapy is very effective for a subset of woman with papillary serous peritoneal adenocarcinoma. A 52 year-old woman underwent [(18)F]-FDG PET/CT for routine health screening. On PET/CT, multiple hypermetabolic lymph nodes were detected in the paraaortic spaces, and there were no other hypermetabolic abnormalities. The patient was diagnosed with an unknown primary cancer that probably originated from the ovary or peritoneum, according to clinical studies and biopsy results. This was not a typical case of a favorable subset of cancer of an unknown primary site, but the tumor showed complete biologic response to taxane based chemotherapy as revealed by PET/CT, and necrotic tumor cells were confirmed by surgery.

Survival in cancer of unknown primary site: population-based analysis by site and histology

BACKGROUND

Cancer of unknown primary (CUP) is diagnosed at a metastatic stage, conferring an unfavorable prognosis. The natural history of the disease is poorly understood, which complicates diagnosis, treatment and follow-up. Population-based survival data are lacking regarding location and histology of metastases.

PATIENTS AND METHODS

From the Swedish Cancer Registry, 18 911 CUP patients were identified between years 1987 and 2008. Survival was analyzed by Kaplan-Meier survival curves and Cox regression.

RESULTS

Adenocarcinoma accounted for 70% of all extranodal cases with a 12-month survival of 17% and the median survival of 3 months. Adenocarcinoma was also the most common histology (33.4%) when metastases were limited to lymph nodes, with a 12-month survival of 41% and median survival of 8 months. For extranodal metastases, the extremes in survival were small intestinal cancer with poor prognosis and mediastinal cancer with favorable prognosis. For nodal metastases, patients affected in the head and neck, axillary and inguinal regions had the best prognosis and those with abdominal and intrapelvic metastases the worst prognosis.

CONCLUSIONS

The present data underline the importance of histology and location of metastasis in assisting clinical decision making: hazard ratios differed by a factor of five among extranodal and nodal metastases.

Carcinomas of an unknown primary origin--diagnosis and treatment

Carcinomas of an unknown primary origin (CUP) account for 3-5% of all malignancies and are thus among the ten most-frequent cancers worldwide. Having a specific and unique phenotype of early and usually aggressive metastatic dissemination with no identifiable primary tumor, CUP are a challenge for physicians. The diagnostic workup of patients with CUP includes a careful clinical and extensive histopathological examination, as well as the use of imaging techniques. CUP can be divided into favorable and unfavorable subsets. Patients with unfavorable CUP subsets have a poor prognosis with a median survival of approximately 8 months; the optimal chemotherapy regimen for these patients remains to be determined. Although studies have focused on the introduction of new cytotoxic agents with broad-spectrum clinical activity (such as gemcitabine, irinotecan, and taxanes), no randomized trial has provided clear evidence of a survival benefit. Molecular targeted therapies that are approved for other solid tumors are now considered for the treatment of patients with CUP. Molecular diagnostic tools, such as DNA microarray analysis, could help in the search for 'lost' CUP origins. In this Review, we describe the clinical evaluation of patients with CUP, and discuss treatment strategies and outcomes of patients with various CUP subsets.

Gene-expression assays and personalized cancer care: tissue-of-origin test for cancer of unknown primary origin

Cancer of unknown primary (CUP) is one of the ten most frequently diagnosed cancers in developed countries and accounts for 3–5% of all new cancer cases. For all cancer management, chemotherapeutic regimens and targeted agents have increasingly become primary-site dependent over the last decade, and thus, accurate identification of the primary site is crucial for CUP patients. Histopathologic examination along with immunohistochemical studies and different imaging modalities are most often performed for this purpose, but still a significant number of patients remain with an unidentified primary. Recently, gene-expression profiling assays have emerged as alternative tests for tumor tissue of origin determination. It is expected that molecular determination of the origin in patients with CUP will aid in the determination of management strategies. It is thus possible that personalized treatment of CUP patients based on molecular classification could significantly improve patient outcomes.

Cancer of unknown primary: progress in the search for improved and rapid diagnosis leading toward superior patient outcomes

This paper explores the enigma of cancer of unknown primary (CUP) in relation to rapidly improving molecular diagnostic approaches. It is based on the first global collaboration meeting on improving research and clinical outcomes in CUP organized by the CUP Foundation. We review the difficulties of classifying this widely heterogeneous disease and the available diagnostic and pathological evaluative techniques, focusing on molecular profiling. Retrospective studies in CUP patients are shown to provide indirect validation of the accuracy of several platforms of gene expression profiling assays that may identify CUP subsets that respond favorably to active chemotherapy regimens. This review concludes that the recent major improvements in pathologic and molecular diagnostics, coupled with new improved therapies for several specific advanced solid tumors, need to be harmonized with more evidence from clinical-translational trials. All patients with CUP could thus be appropriately managed without the constant uncertainty that has previously severely hampered patient care and optimal outcomes. The longer-term objective is to understand the biology of highly metastatic disease, leading to the development of future global therapeutic programs. Current clinical studies, such as CUP-ONE, will address some of these issues.

Breast radiotherapy for occult breast cancer with axillary nodal metastases--does it reduce the local recurrence rate and increase overall survival?

AIMS

The optimal management of axillary lymph node metastases from occult breast cancer (TXN1-2M0) is uncertain and practice varies in the use of primary breast radiotherapy. We conducted a retrospective review to examine clinical outcomes for patients managed with or without primary breast radiotherapy.

MATERIALS AND METHODS

Case records from the clinical oncology database were reviewed to identify patients presenting with axillary nodal metastases but no detectable primary tumour between 1974 and 2003. Fifty-three patients with TXN1-2M0 breast cancer were identified, representing 0.4% of patients managed for breast cancer during this period. Of those tested, 59% had oestrogen receptor-positive tumours. Seventy-seven per cent received ipsilateral breast radiotherapy.

RESULTS

There was a trend towards reduced ipsilateral breast tumour recurrence in patients who received radiotherapy (16% at 5 years, 23% at 10 years) compared with those who did not (36% at 5 years, 52% at 10 years). Similarly, the locoregional recurrence rate was 28% at 5 years for patients who received radiotherapy compared with 53.7% at 5 years for non-irradiated patients. Breast cancer-specific survival was higher (P=0.0073; Log-rank test) in patients who received ipsilateral breast radiotherapy (72% at 5 years, 66% at 10 years) compared with those who did not (58% at 5 years, 15% at 10 years).

CONCLUSION

Primary breast radiotherapy may reduce ipsilateral breast tumour recurrence and may increase survival in patients presenting with axillary lymph node metastases and occult breast primary (TXN1-2M0). Larger studies or prospective registration studies are needed to validate these findings.

Clinical presentation of carcinoma of unknown primary: 14 years of experience

A carcinoma of unknown primary (CUP) is a histologically confirmed metastatic cancer without a definitive primary site after performing a detailed medical examination. The purpose of the study was to classify unfavorable CUPs into more reliable disease entities, which reflect the clinical course. We reviewed the medical records of patients diagnosed with a CUP between January 1995 and March 2008. Patients were classified into a conventional favorable-risk group and a newly proposed unfavorable-risk group according to the clinicopathologic features. Five hundred eighty-six patients were diagnosed with CUPs. Fifty-six (9.6%) patients were classified in the conventional favorable-risk group, and 486 (82.9%) patients were classified in the unfavorable-risk group. We further classified the 486 patients into six subgroups with an unfavorable risk, while excluding 29 patients (5.0%) who were not classifiable. The overall survival of the conventional favorable-risk group was 47.0 months (95% CI, 11.1~82.9 months), which was significantly longer than that of any subgroup of the newly proposed unfavorable-risk group (P < 0.001). Patients with squamous cell carcinoma in the abdominopelvic cavity showed similar overall survival with unfavorable-risk group (P = 0.484). Women with non-papillary malignant ascites had a survival in between the favorable and unfavorable groups (P <  0.001). The newly proposed unfavorable-risk group may assist in classifying CUP patients with an unfavorable risk in a clinically more meaningful way. Squamous cell carcinoma in the abdominopelvic cavity should be considered in the unfavorable-risk group and women with non-papillary malignant ascites in an intermediate-risk group. Further studies with molecular profiling would help in classifying and treating patients with CUPs and an unfavorable risk.