Renal Cell Carcinoma Presenting as Carcinoma of Unknown Primary Site: Recognition of a Treatable Patient Subset

Personalized Therapy Selection by Integration of Molecular Cancer Classification by the 92-Gene Assay and Tumor Profiling in Patients With Cancer of Unknown Primary

PURPOSE

Cancer of unknown primary (CUP) is a syndrome comprising metastatic cancers without a clinically identified primary site. Although patients with CUP have an unfavorable prognosis, treatment with site-specific therapies guided by clinical features, standard pathology, and molecular assays can improve overall survival. The 92-gene assay (CancerTYPE ID) is a gene expression-based classifier that helps identify the tissue of origin for metastatic cancers with unknown or uncertain diagnoses. This study reports the frequency of selected molecular aberrations of oncogenes, including KRAS, IDH1/2, BRCA1/2, and BRAF, in patients with CUP in the MOSAIC database to highlight potential treatment options.

METHODS

MOSAIC is a database of patients with CUP submitted for CancerTYPE ID testing and NeoTYPE biomarker testing. Tumor biopsy samples were analyzed by CancerTYPE ID for tumor type identification and further tested for molecular aberrations of oncogenes, including KRAS, IDH1/2, BRCA1/2, and BRAF.

RESULTS

CancerTYPE ID identified a specific tumor type in 92.5% (2,929 of 3,168) of CUP cases in the MOSAIC database. The most commonly identified histological type was adenocarcinoma (75.4%), with pancreaticobiliary being the most common molecularly diagnosed cancer (24.9%). Aberrations in KRAS, IDH1/2, BRCA, and BRAF genes were identified in 18.8% (n = 597) of biopsies. A cancer-specific US Food and Drug Administration (FDA)-approved or investigational targeted therapy was potentially available for 24.6% (n = 147) of these patients.

CONCLUSION

This retrospective analysis supports incorporating CancerTYPE ID into the evaluation for patients with CUP to help determine the tissue of origin and identify actionable genetic alterations. This approach may allow more patients with CUP to benefit from site-specific FDA-approved targeted therapies or enrollment into clinical trials.

Metastatic renal cell carcinoma with occult primary: a multicenter prospective cohort

Metastatic carcinoma of presumed renal origin (rCUP) has recently emerged as a new entity within the heterogeneous entity of Cancers of Unknown Primary (CUP) but their biological features and optimal therapeutic management remain unknown. We report the molecular characteristics and clinical outcome of a series of 25 rCUP prospectively identified within the French National Multidisciplinary Tumor Board for CUP. This cohort strongly suggests that rCUP share similarities with common RCC subtypes and benefit from renal-tailored systemic treatment. This study highlights the importance of integrating clinical and molecular data for optimal diagnosis and management of CUP.

Periprosthetic metastases in carcinoma of unknown primary: A rare association

ABSTRACT

Septic or aseptic loosening may cause bone loss around artificial prosthesis leading to prosthesis failure. This occurrence due to metastatic infiltration of bone or surrounding soft tissues is rare but has been occasionally reported. We report a case of an elderly lady presenting with swelling and pain at the site of previous hemiarthroplasty performed for traumatic injury. On evaluation, she was found to have a lytic femur lesion with a large soft-tissue component around the prosthetic joint. Biopsy suggested a metastatic carcinoma of renal origin, but screening of kidneys did not reveal any primary lesion. She had additional skeletal metastatic lesions but no other primary site was detected either. She was given palliative radiotherapy and systemic therapy (sunitinib) based on the histologic diagnosis of renal cell origin but did not tolerate it. Thereafter, she is continuing on zoledronate every 4 weeks and best supportive management since 4 months from diagnosis.

Pathological Fracture of the Proximal Humerus Occurred on Metastases of Probable Kidney Origin in the Absence of Primary Lesions: A Case Report

Cancer of unknown primary (CUP) origin represents a diagnostic and therapeutic challenge. These tumours spread to different parts of the body even if the site of origin has not been identified. When renal metastases are observed without an obvious primary lesion, it is important to exclude the possibility of a primary kidney tumour that may be unknown or too small to be detected. The diagnosis of CUP is established after a careful clinical evaluation and diagnostic tests, including blood chemistry and laboratory tests, instrumental exams (CT, MRI, PET, bone scan), biopsy, and molecular and cytogenetic analysis. Once the diagnosis of CUP with kidney metastases is confirmed, treatment depends on the location of the metastases, the patient's health status, and available treatment options. The latter includes surgery to remove metastases, radiation therapy, or systemic treatment such as chemotherapy or immunotherapy. It is important that patients with CUP are evaluated by a multidisciplinary team of specialists, who can contribute to planning the most appropriate treatment. In this article, we report the clinical case of a patient with a pathological fracture of the proximal humerus which occurred on metastases of probable renal origin in the absence of primary lesions.

[Cancer of unknown primary-The new ESMO guidelines]

BACKGROUND

The European Society of Medical Oncology (ESMO) recently published extensively revised guidelines on cancer of unknown primary (CUP). The new version contains the following relevant amendments: with respect to diagnostics of CUP, the current guidelines aim for a more precise and standardized definition of CUP by establishing diagnostic algorithms. Recommendations for molecular diagnostics of cancer tissue have also been implemented. With respect to CUP classification, the favorable category has been revised. A carcinoma with immunohistochemistry typical for renal cell carcinoma (renal-like CUP) was introduced in the new definition of favorable subtypes, for which a specific treatment is indicated. Based on a newly defined oligometastatic situation a subgroup with localized cancer potentially curatively treatable with surgery and/or radiotherapy was introduced into the CUP classification. With respect to treatment of CUP, the current guidelines present options beyond empirical chemotherapy, which is still the standard of care treatment, and pinpoint indications and predictive biomarkers for targeted and immune checkpoint inhibitor treatment.

RELEVANT UPDATES

The European Society of Medical Oncology (ESMO) recently published extensively revised guidelines on the CUP syndrome. The new version contains the following relevant amendments: the current guidelines aim for a more precise and standardized definition of CUP by establishing diagnostic algorithms with respect to the diagnostics of CUP syndrome. Recommendations for molecular diagnostics of cancer tissue have also been implemented. The classification of the CUP syndrome has also been revised. A carcinoma with immunohistochemistry typical for renal cell carcinoma (renal-like CUP) was introduced in the new definition of favorable subtypes, for which a specific treatment is indicated. Based on a newly defined oligometastatic situation a local potentially curatively treatable with surgery and/or radiotherapy subgroup was introduced into the CUP classification. With respect to treatment of the CUP syndrome, the current guidelines present options beyond empirical chemotherapy, which is still the gold standard treatment, and pinpoint indications and predictive biomarkers for targeted and immune checkpoint inhibitor treatment.

SCHLUSSFOLGERUNG

The aim of this review is to present the current state of diagnostics, classification and treatment of CUP syndrome, with a focus on recent developments and revisions implemented in the current ESMO guidelines.

A comparison of DNA sequencing and gene expression profiling to assist tissue of origin diagnosis in cancer of unknown primary

Cancer of unknown primary (CUP) is a syndrome defined by clinical absence of a primary cancer after standardised investigations. Gene expression profiling (GEP) and DNA sequencing have been used to predict primary tissue of origin (TOO) in CUP and find molecularly guided treatments; however, a detailed comparison of the diagnostic yield from these two tests has not been described. Here, we compared the diagnostic utility of RNA and DNA tests in 215 CUP patients (82% received both tests) in a prospective Australian study. Based on retrospective assessment of clinicopathological data, 77% (166/215) of CUPs had insufficient evidence to support TOO diagnosis (clinicopathology unresolved). The remainder had either a latent primary diagnosis (10%) or clinicopathological evidence to support a likely TOO diagnosis (13%) (clinicopathology resolved). We applied a microarray (CUPGuide) or custom NanoString 18-class GEP test to 191 CUPs with an accuracy of 91.5% in known metastatic cancers for high-medium confidence predictions. Classification performance was similar in clinicopathology-resolved CUPs - 80% had high-medium predictions and 94% were concordant with pathology. Notably, only 56% of the clinicopathology-unresolved CUPs had high-medium confidence GEP predictions. Diagnostic DNA features were interrogated in 201 CUP tumours guided by the cancer type specificity of mutations observed across 22 cancer types from the AACR Project GENIE database (77,058 tumours) as well as mutational signatures (e.g. smoking). Among the clinicopathology-unresolved CUPs, mutations and mutational signatures provided additional diagnostic evidence in 31% of cases. GEP classification was useful in only 13% of cases and oncoviral detection in 4%. Among CUPs where genomics informed TOO, lung and biliary cancers were the most frequently identified types, while kidney tumours were another identifiable subset. In conclusion, DNA and RNA profiling supported an unconfirmed TOO diagnosis in one-third of CUPs otherwise unresolved by clinicopathology assessment alone. DNA mutation profiling was the more diagnostically informative assay. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Carcinoma of Unknown Original Identified as Renal Cell Carcinoma by 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Scan: A Report of Two Cases

Imaging is useful in identifying the primary site of an unknown primary cancer, and ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) is an excellent imaging modality for identifying the primary lesion. However, a potential limitation is that ¹⁸F-FDG is physiologically excreted from the kidneys, thus masking renal lesions. In this report, we describe two cases of cancer of unknown origin that were detected as originating from renal cancer on ¹⁸F-FDG PET/CT. Both cases showed abnormal nodular accumulation of ¹⁸F-FDG in the kidney, which can be distinguished from the physiological excretion of ¹⁸F-FDG in the urinary tract. It is clinically crucial to be able to confirm the possibility of renal cancer, and careful observation of the urinary tract with ¹⁸F-FDG PET/CT can be useful.

Extra-renal renal cell carcinoma arising in the kidney proximity but without an identifiable renal primary - an intriguing dilemma: Report of three cases and review of the literature

We report three patients with extra-renal renal cell carcinomas (RCC) found in the renal proximity, but unattached to the kidney. None had a history of RCC or an identifiable primary renal neoplasm at the time of the diagnosis and on follow-up. The patients included two males and one female aged 57, 77 and 63 years, respectively. One carcinomas was found in the perirenal tissue adjacent to the adrenal, one involved the adrenal gland, and one was a retroperitoneal mass found within the lymph nodes. Two extra-renal RCCs represented clear cell RCCs and one was an unclassifiable RCC. No patient had evidence of metastases at presentation and disease progression during the follow-up. This report adds to the literature on this unusual clinical scenario and further supports the concept of extra-renal RCC, which is not a well-recognized clinical phenomenon. We also reviewed other similar reports documenting the absence of identifiable renal primaries in the setting of either disseminated metastatic disease or isolated distant metastases of presumed renal origin. Similarly, some carcinomas of apparent renal derivation have been also identified during a work-up of metastatic carcinomas of unknown primary. The aim of this study is to raise further awareness of this unusual and intriguing clinical scenario that currently lacks a definitive explanation and standardized therapy strategies. Establishing a correct diagnosis may allow treatment with specific targeted therapies in selected clinical cases.

A Challenging Task: Identifying Patients with Cancer of Unknown Primary (CUP) According to ESMO Guidelines: The CUPISCO Trial Experience

BACKGROUND

CUPISCO is an ongoing randomized phase II trial (NCT03498521) comparing molecularly guided therapy versus platinum-based chemotherapy in patients newly diagnosed with "unfavorable" cancer of unknown primary (CUP).

MATERIALS AND METHODS

Patients with an unfavorable CUP diagnosis, as defined by the European Society of Medical Oncology (ESMO), and available cancer tissue for molecular sequencing are generally eligible. Potential patients with CUP entering screening undergo a review involving reference histopathology and clinical work-up by a central eligibility review team (ERT). Patients with "favorable" CUP, a strongly suspected primary site of origin, lack of tissue, or unmet inclusion criteria are excluded.

RESULTS

As of April 30, 2020, 628 patients had entered screening and 346 (55.1%) were screen failed. Screen fails were due to technical reasons (n = 89), failure to meet inclusion and exclusion criteria not directly related to CUP diagnosis (n = 89), and other reasons (n = 33). A total of 124 (35.8%) patients were excluded because unfavorable adeno- or poorly differentiated CUP could not be confirmed by the ERT. These cases were classified into three groups ineligible because of (a) histologic subtype, such as squamous and neuroendocrine, or favorable CUP; (b) evidence of a possible primary tumor; or (c) noncarcinoma histology.

CONCLUSION

Experience with CUPISCO has highlighted challenges with standardized screening in an international clinical trial and the difficulties in diagnosing unfavorable CUP. Reconfirmation of unfavorable CUP by an ERT in a clinical trial can result in many reasons for screen failures. By sharing this experience, we aim to foster understanding of diagnostic challenges and improve diagnostic pathology and clinical CUP algorithms.

IMPLICATIONS FOR PRACTICE

A high unmet need exists for improved treatment of cancer of unknown primary (CUP); however, study in a trial setting is faced with the significant challenge of definitively distinguishing CUP from other cancer types. This article reports the authors' experience of this challenge so far in the ongoing CUPISCO trial, which compares treatments guided by patients' unique genetic signatures versus standard chemotherapy. The data presented will aid future decision-making regarding diagnosing true CUP cases; this will have far-reaching implications in the design, execution, and interpretation of not only CUPISCO but also future clinical studies aiming to find much-needed treatment strategies.

Machine learning analysis using 77,044 genomic and transcriptomic profiles to accurately predict tumor type

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CUP occurs in as many as 3–5% of patients when standard diagnostic tests are not able to determine the origin of cancer.

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MI GPSai (Genomic Prevalence Score) is an AI that uses genomic and transcriptomic data to elucidate tumor origin.

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The algorithm was trained on molecular data from 57,489 cases and validated on 19,555 cases.

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MI GPSai predicted the tumor type out of 21 options in the labeled data set with an accuracy of over 94% on 93% of cases.

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When also considering the second highest prediction, the accuracy increases to 97%.

Cancer of Unknown Primary (CUP) occurs in 3–5% of patients when standard histological diagnostic tests are unable to determine the origin of metastatic cancer. Typically, a CUP diagnosis is treated empirically and has very poor outcomes, with median overall survival less than one year. Gene expression profiling alone has been used to identify the tissue of origin but struggles with low neoplastic percentage in metastatic sites which is where identification is often most needed. MI GPSai, a Genomic Prevalence Score, uses DNA sequencing and whole transcriptome data coupled with machine learning to aid in the diagnosis of cancer. The algorithm trained on genomic data from 34,352 cases and genomic and transcriptomic data from 23,137 cases and was validated on 19,555 cases. MI GPSai predicted the tumor type in the labeled data set with an accuracy of over 94% on 93% of cases while deliberating amongst 21 possible categories of cancer. When also considering the second highest prediction, the accuracy increases to 97%. Additionally, MI GPSai rendered a prediction for 71.7% of CUP cases. Pathologist evaluation of discrepancies between submitted diagnosis and MI GPSai predictions resulted in change of diagnosis in 41.3% of the time. MI GPSai provides clinically meaningful information in a large proportion of CUP cases and inclusion of MI GPSai in clinical routine could improve diagnostic fidelity. Moreover, all genomic markers essential for therapy selection are assessed in this assay, maximizing the clinical utility for patients within a single test.

The diagnostic challenges of patients with carcinoma of unknown primary

INTRODUCTION

Cancer of unknown primary (CUP) is a disease entity encompassing heterogeneous malignancies without a clinically-detectable anatomical primary. It is usually a poor prognosis malignancy with dismal prognosis where molecular and genetic testing were expected to be a major breakthrough.

AREAS COVERED

In this review, we provide an overview of the advances in the understanding of the carcinogenesis, biology, diagnosis and treatment of patients with CUP. This review focuses on the advantages and inconveniences of immunohistochemistry and CUP classifiers in assessing the progress in the management of CUP.

EXPERT OPINION

CUP classifiers were expected to gradually replace the classical multistep approach in identifying the culprit tumors to guide site-specific therapy. Immunohistochemistry staining led to the prediction of a single tissue of origin in 10.8-51%. CUP classifiers identified the primary site in 61-89% of these cases and were concordant with immunohistochemistry in 57.1-100%. Immunohistochemistry is cheap, fast and broadly available whereas CUP classifiers are less widely available and have not been validated in randomized control trials. The diagnostic recommendations consist of a standard pathology evaluation based on morphology and algorithmic immunohistochemistry assessment. Physicians should weigh in the input of the CUP classifier to the clinical picture and pathology investigations before performing additional investigations.

Cytological diagnosis of Xp11 translocation renal cell carcinoma: An unusual suspect in bone metastases from unknown primary malignancies

BACKGROUND

Renal cell carcinoma (RCC) constitutes 3% of all cancers, with a higher incidence in patients with age between 60 and 70 years. RCC frequently present as a metastatic tumor at diagnosis, and bones represent one of the most frequent sites. Many cases, mainly in young patients, includes the Xp11 translocation RCC. The cytological diagnosis of Xp11 translocation RCC in adult population it is rarely performed, likely for the morphological overlap with other adult renal cell carcinoma subtypes.

METHODS

We retrospectively analyze a series of 92 adult patients with metastatic bone tumors, diagnosed on fine-needle aspiration cytology (FNAC) samples, focusing mainly on the cytological, immunophenotypic and molecular features of Xp11 translocation RCC.

RESULTS

In our series 6 of 92 (6.5%) cases were metastatic RCC (mRCC), among them 2 cases were metastasis from Xp11translocation RCC. Those cases showed a bloody background, with several groups of atypical cells arranged in syncytial groups or in papillary groups composed by atypical cells with abundant cytoplasm, with scattered clear cells. TFE3 was positive on immunocytochemical analysis and specific translocation t(Xp11.23) was detected by FISH analysis.

CONCLUSIONS

In adult patients with mRCC, it is necessary to consider also Xp11 translocation RCC among the diagnostic hypotheses. FNAC represents a valid tool to investigate bone lesions but cytological features of Xp11 translocation RCC are still poorly described and must necessarily be better defined.

Progress in refining the clinical management of cancer of unknown primary in the molecular era

Cancer of unknown primary (CUP) is an enigmatic disease entity encompassing heterogeneous malignancies without a detectable primary tumour, despite a thorough diagnostic workup. A minority of patients with CUP (15-20%) can be assigned a putative primary tissue of origin according to clinical and histopathological findings and typically have a more favourable prognosis with the use of corresponding tumour type-specific therapies. Thus, the majority of patients with CUP have disease that cannot be assigned to a culprit primary tumour, are treated with empirical chemotherapy and have a poor prognosis. In the molecular era, the use of (epi)genomic or transcriptomic CUP classifiers and DNA or RNA sequencing offers two, sometimes overlapping, therapeutic strategies: tumour type-specific therapy and biomarker-guided therapy. Published data reveal that the accuracy of site-of-origin predictions made using CUP classifiers ranges between 54% and 98% when compared with the assignment made according to the recommended clinicopathological criteria. These advances have led to promising results in non-randomized prospective studies evaluating the efficacy of tumour type-specific therapy; however, the favourable outcomes were not confirmed in randomized controlled studies comparing this approach with standard empirical chemotherapy. Currently, the evidence supporting the use of biomarker-guided therapies is limited to case reports and small case series. In this Review, we discuss the clinical management of CUP in the era of precision medicine. We focus on the advances in understanding the biology of CUP, the implications for the diagnosis and classification of CUP according to the tissue of origin and the shift away from empirical therapy towards tailored therapy.

Carcinoma of Unknown Primary Site (CUP) With Metastatic Renal-Cell Carcinoma (mRCC) Histologic and Immunohistochemical Characteristics (CUP-mRCC): Results From Consecutive Patients Treated With Targeted Therapy and Review of Literature

BACKGROUND

Carcinoma of unknown primary site (CUP) is a heterogenous group of metastatic cancer with no detectable primary tumor site. Diagnostic assessment occasionally presents CUP with metastatic renal-cell carcinoma (mRCC) histologic and immunohistochemical characteristics (CUP-mRCC). Efficacy and toxicity data for vascular endothelial growth factor inhibitor therapies in CUP-mRCC patients are few.

PATIENTS AND METHODS

We retrospectively reviewed consecutive patients with CUP-mRCC at a single institution between 2007 and 2018. Treatment outcomes were assessed from initiation of renal-cell carcinoma-specific therapy, including response rate, progression-free survival, and overall survival.

RESULTS

Ten patients with CUP-mRCC were identified. Median age was 64 years. Histologies were clear-cell (30%), papillary type II (20%), and unclassified renal-cell (50%) carcinoma. International Metastatic Renal Cell Carcinoma Database Consortium risk group were favorable, intermediate, and poor in 0, 40%, and 60%, respectively. One patient received empiric first-line chemotherapy. Targeted treatments were pazopanib (n = 7), sunitinib (n = 2), and sorafenib (n = 1). Objective response rate was 40%, progression-free survival was 2.5 months (95% confidence interval, 1.2-3.8), and overall survival was 5.7 months (95% confidence interval, 0-24.0). Stratified for International Metastatic Renal Cell Carcinoma Database Consortium risk, overall survival in intermediate versus poor risk group were 18.6 months and 2.3 months, respectively. Second-line therapy did not result in disease control. No new or unexpected toxicities were observed.

CONCLUSION

CUP-mRCC treated with vascular endothelial growth factor-targeted therapy is valid, feasible, and safe even though these patients had several negative prognostic factors. CUP-mRCC patients should be identified among CUP patients for specific renal-cell carcinoma therapy.