Forty years experience of treating cancer of unknown primary

Diagnostic Utility of a 90-Gene Expression Assay (Canhelp-Origin) for Patients with Metastatic Cancer with an Unclear or Unknown Diagnosis

BACKGROUND

Metastatic cancers with unclear or unknown origins pose significant challenges in diagnosis and management, frequently leading to suboptimal outcomes. Studies have demonstrated that a 90-gene expression assay is effective in predicting the primary origin and guiding the site-specific therapy to improve prognosis. This study aimed to evaluate the clinical effectiveness of a 90-gene expression assay in patients with unclear or unknown diagnoses.

METHODS

The study encompassed patients for whom a 90-gene expression assay was requested as part of standard care. Data on patient demographics, tumor characteristics, and clinical history were collected. The assay's performance was evaluated by comparing its predicted tumor type with the final histopathological diagnosis.

RESULTS

Among 303 cases analyzed, a 90-gene expression assay successfully identified a molecular-based tumor type for 295 (97.4%) patients. Comparison with histopathological diagnosis revealed an overall agreement of 88.5% (170/192). In patients with a single suspected primary site (n = 140), the assay confirmed the suspected diagnosis in 90.7% of cases. For those with a differential diagnosis (n = 52), the assay narrowed down the possibilities in 82.7% of cases. Moreover, in cases where the histopathology report indicated cancer of unknown primary (n = 103), the assay offered a molecular tumor type prediction with potential clinical significance.

CONCLUSIONS

This study demonstrates the significant impact of a 90-gene expression assay on diagnosis and potential treatment selection for difficult-to-diagnose patients, highlighting its clinical value as a standardized molecular approach to streamline further diagnostic testing for patients with metastatic cancer of unclear or unknown origin. Further prospective study is required to assess whether employing molecular diagnostic classifiers enhances clinical outcomes in these patients.

Poorly differentiated squamous cell carcinoma of unknown primary location a case report of perineal presentation

INTRODUCTION

Cancers of unknown primary origin (CUP) pose a significant clinical challenge, representing a small percentage (1 to 5 %) of overall cancer cases. The patient is a 31-year-old male who has been diagnosed with poorly differentiated infiltrating squamous cell carcinoma, which has been classified as CUP. The exceptional perineal presentation and diagnostic process serve as a reminder of the diverse nature of CUPs and the crucial role played by advanced imaging methods and a multidisciplinary approach. The inclusion of this case, the seventh one in the literature, deepens our understanding of CUPs.

PRESENTATION OF CASE

A 31-year-old man came in with a gradual onset of perineal pain that had been worsening for the past six months. A nodular lesion in the urogenital triangle, infiltrating the bulbo spongiosus muscle, was surgically removed. The histopathology results confirmed a poorly differentiated squamous cell carcinoma. Despite conducting extensive examinations, the multidisciplinary team was unable to determine the source of the tumour, classifying it as CUP. One year post-surgery, the patient remains in complete remission.

DISCUSSION

The management of CUPs can be challenging because of the variety of their origins and presentations. The importance of advanced imaging, pathological and biological techniques, as well as meticulous surgical intervention, is emphasized in this case, as it helps in avoiding unnecessary adjuvant therapies.

CONCLUSION

This case highlights the significance of a customized and interdisciplinary approach in effectively managing CUPs, especially when they present in unusual ways. Timely surgical intervention, backed by comprehensive imaging and pathological analysis, can result in positive results.

Assessing the utility of molecular diagnostic classification for cancers of unknown primary

BACKGROUND

Roughly 5% of metastatic cancers present with uncertain origin, for which molecular classification could influence subsequent management; however, prior studies of molecular diagnostic classifiers have reported mixed results with regard to clinical impact. In this retrospective study, we evaluated the utility of a novel molecular diagnostic classifier by assessing theoretical changes in treatment and additional testing recommendations from oncologists before and after the review of classifier predictions.

METHODS

We retrospectively analyzed de-identified records from 289 patients with a consensus diagnosis of cancer of uncertain/unknown primary (CUP). Two (or three, if adjudication was required) independent oncologists separately reviewed patient clinical information to determine the course of treatment before they reviewed results from the molecular diagnostic classifier and subsequently evaluated whether the predicted diagnosis would alter their treatment plan.

RESULTS

Results from the molecular diagnostic classifier changed the consensus oncologist-reported treatment recommendations for 235 out of 289 patients (81.3%). At the level of individual oncologist reviews (n = 414), 64.7% (n = 268) of treatment recommendations were based on CUP guidelines prior to review of results from the molecular diagnostic classifier. After seeing classifier results, 98.1% (n = 207) of the reviews, where treatment was specified (n = 211), were guided by the tissue of origin-specific guidelines. Overall, 89.9% of the 414 total reviews either expressed strong agreement (n = 242) or agreement (n = 130) that the molecular diagnostic classifier result increased confidence in selecting the most appropriate treatment regimen.

CONCLUSIONS

A retrospective review of CUP cases demonstrates that a novel molecular diagnostic classifier could affect treatment in the majority of patients, supporting its clinical utility. Further studies are needed to prospectively evaluate whether the use of molecular diagnostic classifiers improves clinical outcomes in CUP patients.

Risk factors for cancer of unknown primary: a literature review

Cancer of Unknown Primary (CUP) is metastatic cancer with an unidentifiable primary tumour origin during life. It remains difficult to study the occurrence and aetiology of CUP. Hitherto, it is unclear whether risk factors are associated with CUP, yet identifying these factors could reveal whether CUP is a specific entity or a cluster of metastasised cancers from various primary tumour origins. Epidemiological studies on possible CUP risk factors were systematically searched in PubMed and Web of Science on February 1^st, 2022. Studies, published before 2022, were included if they were observational human-based, provided relative risk estimates, and investigated possible CUP risk factors. A total of 5 case-control and 14 cohort studies were included. There appears to be an increased risk for smoking in relation to CUP. However, limited suggestive evidence was found to link alcohol consumption, diabetes mellitus, and family history of cancer as increased risks for CUP. No conclusive associations could be made for anthropometry, food intake (animal or plant-based), immunity disorders, lifestyle (overall), physical activity, or socioeconomic status and CUP risk. No other CUP risk factors have been studied. This review highlights smoking, alcohol consumption, diabetes mellitus and family history of cancer as CUP risk factors. Yet, there remains insufficient epidemiological evidence to conclude that CUP has its own specific risk factor profile.

The diagnosis and treatment for a patient with cancer of unknown primary: A case report

Background: Cancer of unknown primary (CUP) is a class of metastatic malignant tumors whose primary location cannot be determined. The diagnosis and treatment of CUP are a considerable challenge for clinicians. Herein, we report a CUP case whose corresponding primary tumor sites were successfully identified, and the patient received proper treatment. Case report: In February 2022, a 74-year-old woman was admitted to the Medical Oncology Department at Sir Run Run Shaw Hospital for new lung and intestinal tumors after more than 9 years of breast cancer surgery. After laparoscopically assisted right hemicolectomy, pathology revealed mucinous adenocarcinoma; the pathological stage was pT2N0M0. Results from needle biopsies of lung masses suggested poorly differentiated cancer, ER (-), PR (-), and HER2 (-), which combined with the clinical history, did not rule out metastatic breast cancer. A surgical pathology sample was needed to determine the origin of the tumor tissue, but the patient's chest structure showed no indications for surgery. Analysis of the tumor's traceable gene expression profile prompted breast cancer, and analysis of next-generation amplification sequencing (NGS) did not obtain a potential drug target. We developed a treatment plan based on comprehensive immunohistochemistry, a gene expression profile, and NGS analysis. The treatment plan was formulated using paclitaxel albumin and capecitabine in combination with radiotherapy. The efficacy evaluation was the partial response (PR) after four cycles of chemotherapy and two cycles combined with radiotherapy. Conclusion: This case highlighted the importance of identifying accurate primary tumor location for patients to benefit from treatment, which will provide a reference for the treatment decisions of CUP tumors in the future.

Late presentation during the COVID-19 pandemic of severe procidentia: a high-grade poorly differentiated sarcoma of unknown origin

High-grade poorly differentiated sarcomas of unknown primary origin constitute a rare entity and are characterised by wide histopathological diversity and atypical presentations. We present such an unusual case attending with severe procidentia in a 68-year-old postmenopausal female. On review of the literature, there are no similar cases reported. Herein, we present this case as in view of its rare clinical appearance combined with the advanced and histologically uncertain nature of the tumour, which raised significant challenges regarding diagnosis and surgical management in considerations of oncological hygiene and risk of tumour spillage. This was further potentiated by delay in diagnosis and treatment due to the COVID-19 pandemic.

[Cervical CUP syndrome]

The term CUP syndrome (cancer of unknown primary) refers to a multifaceted clinical picture in which the affected patients have lymph node and/or distant metastases without the location of the primary tumor being known. The criteria of CUP syndrome are fulfilled if a histologically or cytologically confirmed malignancy is present without a detectable primary tumor after completion of the primary diagnosis. Due to the usually poor prognosis and the manifold appearance, which often does not allow a standardized therapy, cervical CUP syndrome makes specific demands on clinical and imaging diagnostics. Using modern techniques such as positron emission tomography-computed tomography (PET-CT), imaging plays a key role in the detection of a possible occult primary tumor as well as in staging and prognosis assessment.

Pivotal role of PET/CT in characterization of occult metastasis with undetermined origin

Background

The purpose of this multicenter diagnostic accuracy test study was conducted to assess the role of positron emission tomography/computed tomography in the detection of primary tumor in cases of metastasis of undetermined primary site, to estimate its capability in detecting additional lesions as well as evaluating disease burden and staging. This multicentric diagnostic accuracy test study included 175 patients with pathologically proven, radiologically, and/or clinically suspected metastatic lesions of undetermined primary site. Clinical, surgical, and histopathologic findings and correlative imaging modalities were used to assess the results of PET/CT; the accuracy of PET/CT was expressed in terms of sensitivity and specificity, positive and negative predictive values.

Results

The study included 175 patients; PET-CT-positive lesions suggestive of primary malignant tumors were detected in 105 out of 175 patients. These lesions were pathologically proven to be malignant (true positive) in 100/175 patients (57.1%). Five out of 175 patients (2.9%) proved to be falsely positive after pathologic assessment; 70 out of 175 patients (40%) were negative for detection of primary malignancy all over the body by PET/CT (true negative) with no false negative results. PET/CT achieved a sensitivity of 100%, and specificity of 93.3% in detection of unknown primary tumor location.

Conclusion

PET/CT is an effective modality for early detection of the primary tumor site in patients with cancer of undetermined primary (CUP) which facilitates early selection of appropriate treatment protocols that will improve patients’ prognosis.

What can we learn from cancer of unknown primary in canine oncology?

Cancer of unknown primary (CUP) represents a heterogeneous group of metastatic tumors that lack an identifiable primary site despite an extensive diagnostic work-up. It is a well-recognized entity that is characterized by early dissemination, aggressive clinical course, unpredictable metastatic pattern, intrinsic treatment resistance, and a dismal prognosis. Despite the molecular diagnostic workup and personalized therapy, the expected improvements in the diagnosis and treatment of CUP have not been achieved. Comparative oncology has a promising role in the exchange of knowledge and practices between humans and canines. Therefore, we intended to review the literature reporting on CUP in dogs in order to identify some interesting parallels and unique results that could be transposed to in-human research.

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.

Cancer of Unknown Primary Site: Real Entity or Misdiagnosed Disease?

Metastasis is a late event in the progression of any tumour. However, invasive cancers are occasionally detected in the form of metastatic lesions without a clearly detectable primary tumour. Cancer of unknown primary site (CUP) is defined as a confirmed metastatic tumour, with unknown primary tumour site, despite the standardized diagnostic approach that includes clinical history, routine laboratory tests, and complete physical examination. Due to the lack of basic research on its primary causes, CUP is appropriately termed an 'orphan' cancer. Nevertheless, CUP accounts for 2-5% of diagnosed malignancies. To date, it is unclear whether CUP is an entity with primary dormancy as its hallmark or an entity with genetic abnormalities that cause it to manifest as a primary metastatic disease. In this review, we discuss different aspects of CUP, including its current diagnostic methods, angiogenesis effectors, relationship with cancer stem cells and current treatments.

Exploring the biological hallmarks of cancer of unknown primary: where do we stand today?

Cancer of unknown primary (CUP) affects a small percentage of the general population. Nonetheless, a substantial number of these patients have a poor prognosis and consequently succumb to their illness within a year of diagnosis. The natural history of CUP is characterised by early metastasis from the unknown primary site, aggressive course and resistance to conventional chemotherapy. Unfortunately, the processes by which this orphan disease originates and progresses have not been fully elucidated and its biology remain unclear. Despite the conceptual progress in genetic and molecular profiling made over the past decade, recognition of the genetic and molecular abnormalities involved in CUP, as well as the identification of the tissue of origin remain unresolved issues. This review will outline the biology of CUP by exploring the hallmarks of cancer in order to rationalise the complexities of this enigmatic syndrome. This approach will help the reader to understand where research efforts currently stand and the pitfalls of this quest.

The role of site-specific therapy for cancers of unknown of primary: A meta-analysis

Cancers of unknown primary (CUP) are among the most common causes of death due to cancer, are associated with a poor prognosis and have few therapeutic options available. Molecularly-guided site-specific treatments were explored based on the assumption that CUP are similar in their response to treatment of predicted primary tumours. Given the discordant results between these studies, a meta-analysis using a random-effects model and the inverse variance method was performed. MEDLINE and conference abstracts of American Society of Clinical Oncology (ASCO) and European Society of Medical Oncology (ESMO) meetings were searched from inception until November 2019. A trend towards improved OS was noted with site-specific versus empiric treatment for CUP (HR = 0.73; 95% confidence interval (CI) 0.52-1.02). There was significant heterogeneity across the four studies (I [2] = 79%; p = 0.002) but no significant difference was noted between the treatment effect in the two subgroups (randomised vs. non-randomised; p = 0.07). The test for overall effect for progression free survival, which had only been reported for the two randomised studies, was not statistically significant (HR = 0.93; 95% CI 0.74-1.17), with little heterogeneity between studies (I [2] = 0%; p = 0.77). The results of this meta-analysis highlight the significant heterogeneity between the prospective studies comparing molecularly tailored to empiric therapy for CUP and the need for other randomised studies including only primary tumors with available effective therapies.

Advances in the management of brain metastases from cancer of unknown primary

Cancer of unknown primary accounts for 3-5% of all cancers for which an adequate investigation does not identify the primary tumor. The particular subset of brain metastasis in cancer of unknown primary (BMCUP) is a clinical challenge that lacks standardized diagnostic and therapeutic options. It is diagnosed predominantly in male patients in the sixth decade of age with complaints of headache, neurological dysfunction, cognitive and behavioral disturbances and seizures. The therapeutic approach to patients with BMCUP relies on local control and systemic treatment. Surgery or stereotactic radiosurgery and/or whole brain radiation therapy seems to be the cornerstone of the treatment approach to BMCUP. Systemic therapy remains essential as cancers of unknown primary are conceptually metastatic tumors. The benefits of chemotherapy were disappointing whereas those of targeted therapies and immune checkpoint inhibitors remain to be evaluated. In this Review, we address the advances in the diagnosis and treatment of BMCUP.

Familial cancer of unknown primary

Cancer of unknown primary site (CUP) is a deadly disease diagnosed through metastases at various organs without primary tumor identification. Despite the major molecular and technological advances, the carcinogenesis of CUP remains enigmatic which hampers adequate study design of treatments leading to survival improvement. To date, the pathogenesis of CUP is still debatable with one hypothesis considering CUP simply a group of metastatic tumors with unidentified primaries and another considering it a distinct entity with specific genetic and phenotypic aberrations. Familial CUP seems to favor the first hypothesis due to common genetic predisposition factors between known primaries and CUP. Two clinical implications may be withdrawn from the pathogenesis of familial clustering of CUP. The detailed family history and environmental risk factors may orient towards the primary tumor identification. Smoking avoidance and adherence to general population guidelines for cancer screening would be strongly encouraged.

Liquid biopsy: a new diagnostic, predictive and prognostic window in cancers of unknown primary

Cancer of unknown primary (CUP) is a heterogeneous group of metastatic cancers characterised by early dissemination of metastases in the absence of any identifiable primary site. Most patients with CUP have poor prognosis with the traditional diagnostic and treatment modalities. Recognising the putative primary tumour is hypothesised to ameliorate the prognosis of patients with CUP by guiding treatment decisions. The active efforts in molecular oncology have shown that gene expression profiling is able to identify the primary tumour site and to determine targetable mutations. In this regard, liquid biopsy opens a new diagnostic, predictive and prognostic window in CUP that may lead to substantial improvement in the management of patients with CUP.

A naive Bayes algorithm for tissue origin diagnosis (TOD-Bayes) of synchronous multifocal tumors in the hepatobiliary and pancreatic system

Synchronous multifocal tumors are common in the hepatobiliary and pancreatic system but because of similarities in their histological features, oncologists have difficulty in identifying their precise tissue clonal origin through routine histopathological methods. To address this problem and assist in more precise diagnosis, we developed a computational approach for tissue origin diagnosis based on naive Bayes algorithm (TOD-Bayes) using ubiquitous RNA-Seq data. Massive tissue-specific RNA-Seq data sets were first obtained from The Cancer Genome Atlas (TCGA) and ∼1,000 feature genes were used to train and validate the TOD-Bayes algorithm. The accuracy of the model was >95% based on tenfold cross validation by the data from TCGA. A total of 18 clinical cancer samples (including six negative controls) with definitive tissue origin were subsequently used for external validation and 17 of the 18 samples were classified correctly in our study (94.4%). Furthermore, we included as cases studies seven tumor samples, taken from two individuals who suffered from synchronous multifocal tumors across tissues, where the efforts to make a definitive primary cancer diagnosis by traditional diagnostic methods had failed. Using our TOD-Bayes analysis, the two clinical test cases were successfully diagnosed as pancreatic cancer (PC) and cholangiocarcinoma (CC), respectively, in agreement with their clinical outcomes. Based on our findings, we believe that the TOD-Bayes algorithm is a powerful novel methodology to accurately identify the tissue origin of synchronous multifocal tumors of unknown primary cancers using RNA-Seq data and an important step toward more precision-based medicine in cancer diagnosis and treatment.

PET/MR Outperforms PET/CT in Suspected Occult Tumors

BACKGROUND

To compare the diagnostic accuracy of PET/MR and PET/CT in patients with suspected occult primary tumors.

METHODS

This prospective study was approved by the institutional review board. Sequential PET/CT-MR was performed in 43 patients (22 male subjects; median age, 58 years; range, 20-86 years) referred for suspected occult primary tumors. Patients were assessed with PET/CT and PET/MR for the presence of a primary tumor, lymph node metastases, and distant metastases. Wilcoxon signed-rank test was performed to compare the diagnostic accuracy of PET/CT and PET/MR.

RESULT

According to the standard of reference, a primary lesion was found in 14 patients. In 16 patients, the primary lesion remained occult. In the remaining 13 patients, lesions proved to be benign. PET/MR was superior to PET/CT for primary tumor detection (sensitivity/specificity, 0.85/0.97 vs 0.69/0.73; P = 0.020) and comparable to PET/CT for the detection of lymph node metastases (sensitivity/specificity, 0.93/1.00 vs 0.93/0.93; P = 0.157) and distant metastases (sensitivity/specificity, 1.00/0.97 vs 0.82/1.00; P = 0.564). PET/CT tended to misclassify physiologic FDG uptake as malignancy compared with PET/MR (8 patients vs 1 patient).

CONCLUSIONS

PET/MR outperforms PET/CT in the workup of suspected occult malignancies. PET/MR may replace PET/CT to improve clinical workflow.

Diagnostic Accuracy of 18F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography in the Evaluation of Carcinoma of Unknown Primary

Objective:

Detection of primary tumor site in patients with carcinoma of unknown primary (CUP) syndrome has always been a diagnostic dilemma, necessitating extensive workup. Early detection of primary tumor site coupled with specific therapy improves prognosis. The low detection rate of the primary tumor site can be attributed to the biological behavior or the small size of the primary tumor to be detected by conventional imaging. The objective of this study was to evaluate the diagnostic accuracy of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography-computed tomography (PET-CT) in detecting CUP.

Methods:

A retrospective, cross-sectional analysis of 100 PET-CT scans of patients with CUP syndrome between November 2009 and December 2013 was performed. Eighteen patients whose final histopathology results could not be obtained for correlation were excluded from analysis. The hypermetabolic sites were assessed in correlation with histopathology. The diagnostic accuracy, sensitivity, specificity, positive predictive value and negative predictive values were assessed for PET-CT.

Results:

Out of the 82 patients, primary tumor was correctly identified in 57.3% patients by ¹⁸F-FDG PET-CT (true positive). The PET-CT scan results were negative for primary site localization in 15% of patients (false negative). While 21% had true negative results, 7.3% displayed false positive results. PET-CT scan upstaged the disease in 27% cases. Overall, the diagnostic accuracy was found to be 78%, sensitivity 80%, specificity 74%, positive predictive value 88.7% and negative predictive value 59%.

Conclusion:

Our data supports the utility of ¹⁸F-FDG PET-CT scan in the localization and staging of CUP syndrome.

Diagnostic Imaging Efficacy In Metastases From Unknown Primary Site--Own Material

Cancer of Unknown Primary Origin (CUPO) is defined by the presence of metastatic lesions, diagnosed by means of cytological or pathological evaluation, for which no primary site can be detected during a thorough examination. The clinical investigation, directed at locating the site of the neoplastic lesion, is determined by the results of laboratory tests, imaging procedures, and pathological examinations. It is also essential to conduct a complete medical history and thorough physical examination. The detection of the primary site allowed to introduce specific therapy, which can offer clinical benefits, considering a favorable prognosis. The aim of the study was to assess the range of diagnostic procedures performed in patients with CUPO and efficacy in identifying the primary lesion.

MATERIAL AND METHODS

Retrospective analysis comprised a group of 29 patients with CUPO, operated between January, 2002 and December, 2011, at the Department of Surgical Oncology, Medical University in Łódź. The study group comprised 16 male and 13 female patients; median age at presentation was 58.3 years (ranging between 30-79 years).

RESULTS

Detailed diagnostic management depending on the location of metastatic lesions and their histological type was performed in 20 of the 29 study patients (69%). Considering the remaining 9 (31%) patients detailed diagnostics was not performed, due to the patients' poor general condition. In 55% (11/20) of patients subject to detailed diagnostics, the primary neoplastic lesion was determined.

CONCLUSIONS

Considering the study group, most patients with cancer of unknown primary origin were characterized by a favorable prognosis, which justified thorough diagnostics, in order to establish the primary neoplastic lesion. The introduction of diagnostic examinations enabled to identify the primary site of the tumor in more than 50% of patients. With the development of imaging methods one can expect improvement of unsatisfactory results, considering the detection of primary neoplastic foci.

[Radiological diagnostics in CUP syndrome]

CLINICAL/METHODICAL ISSUE

Imaging plays an essential role in the therapeutic management of cancer of unknown primary (CUP) patients for localizing the primary tumor, for the identification of tumor entities for which a dedicated therapy regimen is available and for the characterization of clinicopathological subentities that direct the subsequent diagnostic and therapeutic strategy.

STANDARD RADIOLOGICAL METHODS

Modalities include conventional x-ray, computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound as well as positron emission tomography (PET)-CT and MRI-PET.

PERFORMANCE

In whole body imaging CT has a high sensitivity for tumor entities which frequently present as a metastasized cancer illness. According to the current literature CT is diagnostic in 86% of patients with pancreatic carcinoma, in 36% of patients with colon carcinoma and in 74% of patients with lung carcinoma. Additionally a meta-analysis showed that for patients with squamous cell carcinoma and cervical lymph node metastases a positive diagnosis was possible in 22% of the cases using CT, in 36% using MRI and in 28-57% using 18F-fluorodeoxyglucose PET-CT ((18)F-FDG PET-CT). In addition, MRI plays an important role in the localization of primary occult tumors (e.g. breast and prostate) because of its high soft tissue contrast and options for functional imaging.

ACHIEVEMENTS

At the beginning of the diagnostic algorithm stands the search for a possible primary tumor and CT of the neck, thorax and abdomen is most frequently used for whole body staging. Subsequent organ-specific imaging examinations follow, e.g. mammography in women with axillary lymphadenopathy. For histological and immunohistochemical characterization of tumor tissue, imaging is also applied to identify the most accessible and representative tumor manifestation for biopsy. Tumor biopsy may be guided by CT, MRI or ultrasound and MRI also plays a central role in the localization of primary occult tumors because of superior soft tissue contrast and options for functional imaging (perfusion, diffusion), e.g. investigation of breast carcinoma or prostate carcinoma.

PRACTICAL RECOMMENDATIONS

Whole body staging stands at the beginning of the diagnostic algorithm in CUP syndrome to localize a potential primary tumor. Clinically, contrast-enhanced CT of the neck, thorax and abdomen is frequently applied; however, many studies have demonstrated augmented sensitivity of (18)F-FDG PET-CT for the detection of primary tumors and metastatic tumor manifestations.

Annexin A10 is an immunohistochemical marker for adenocarcinoma of the upper gastrointestinal tract and pancreatobiliary system

AIMS

Annexin A10 (ANXA10) is a calcium- and phospholipid-binding protein expressed normally in the gastric mucosa. In this study, we evaluated the potential use of ANXA10 as a diagnostic marker.

METHODS AND RESULTS

We observed ANXA10 expression in the gastric mucosa, the Brunner gland of the duodenum and the urothelium, but absence of expression in other normal organs. Following the screening of 1327 primary carcinomas of major organs, we identified ANXA10 expression in 46% of gastric, 72% of ampullary, 78% of pancreatic and 33% of biliary adenocarcinomas. ANXA10 was expressed in 83% of non-invasive urothelial carcinomas, but was expressed in only 9% of invasive urothelial carcinomas. ANAX10 was rarely expressed in carcinomas of other organs. Of 227 metastatic adenocarcinomas, ANXA10 was expressed in 83% of metastatic pancreatic and 47% of metastatic gastric adenocarcinomas, but was expressed in only 2% of metastatic adenocarcinomas from other organs. In the liver, the sensitivity and specificity for identifying the pancreas as the primary site of metastatic adenocarcinoma were 83 and 95%, respectively.

CONCLUSION

Our study results indicate that the inclusion of ANXA10 in an immunohistochemical panel will be helpful in the differential diagnosis of adenocarcinoma of an unknown primary site.

Optimal therapeutic management of patients with distinct clinicopathological cancer of unknown primary subsets

Cancer of unknown primary sites (CUP) is a compilation of various malignant entities--the majority of which behave aggressively and carry poor prognosis. CUP is classified into two different clinicopathological groups: the unfavourable (poor-prognosis) and the favourable (good-prognosis) group. Patients with favourable subsets are treated relevant to the hidden primary tumour chemotherapy regimens and/or radiotherapy. These patients exhibit better responses and prolonged survival. On the other hand, patients of unfavourable subsets are treated with various chemotherapy combinations of platinum- or taxane-containing regimens. Unfortunately, responses and overall survival in this group of CUP patient are not very promising. Several independent prognostic factors have been associated with survival of CUP patients. Since CUP is not an unknown disease, emerging therapeutic innovations are warranted.

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.

Cancers of unknown primary origin: current perspectives and future therapeutic strategies

It is widely accepted that systemic neoplastic spread is a late event in tumour progression. However, sometimes, rapidly invasive cancers are diagnosed because of appearance of metastatic lesions in absence of a clearly detectable primary mass. This kind of disease is referred to as cancer of unknown primary (CUP) origin and accounts for 3-5% of all cancer diagnosis. There is poor consensus on the extent of diagnostic and pathologic evaluations required for these enigmatic cases which still lack effective treatment. Although technology to predict the primary tumour site of origin is improving rapidly, the key issue is concerning the biology which drives early occult metastatic spreading. This review provides the state of the art about clinical and therapeutic management of this malignant syndrome; main interest is addressed to the most recent improvements in CUP molecular biology and pathology, which will lead to successful tailored therapeutic options.

Lymph node metastasis of squamous cell carcinoma from an unknown primary in the upper and middle neck: Impact of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography

PURPOSE

The purpose of this study was to assess the potential of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) imaging for detection of the primary tumor and its impact on treatment planning in patients presenting with cancer of unknown primary and squamous cell carcinoma (SCC)-positive cervical lymph nodes of the upper and middle neck.

METHODS

The study population consisted of 18 consecutive patients with biopsy-proven SCC involving lymph nodes of the upper and middle neck region and negative conventional diagnostic procedures with regard to the location of the primary. All patients underwent FDG-PET/CT according to a standard procedure in search for the primary, unidentified tumor.

RESULTS

In none of the patients FDG-PET/CT was able to indicate a primary tumor localization. Although FDG-PET/CT did identify all sites of known lymph node involvement, neither additional sites of lymph node involvement nor sites of distant metastases were identified. Accordingly, FDG-PET/CT did not impact patient treatment planning.

CONCLUSIONS

In this series, including patients suffering from lymph node metastases by an SCC of unknown primary in the upper and middle neck, FDG-PET/CT was unable to identify a primary tumor. In addition, FDG-PET/CT did not modify the treatment planning in any of the patients studied.

PET and PET/CT for unknown primary tumors

Carcinoma of unknown primary (CUP) is defined as histologically proven metastatic disease that, after a complete diagnostic work-up, yields no primary detectable tumor. CUP is one of the ten most frequent cancers, with overall poor outcome. Detection of the unknown primary tumor is of crucial importance in this scenario, since it might help to select and offer definitive treatment, which, in turn, may improve patient prognosis. Additional diagnostic work-up, usually consisting of a combination of several radiological and endoscopic investigations and serum tumor marker studies, can be time consuming, expensive, and pose a significant burden to the patient. The final diagnostic yield of these tests is often limited. Combined positron emission tomography/computed tomography (PET/CT), using the radiotracer (18)F-fluoro-2-deoxyglucose (FDG), may be of great value in the management of patients with CUP for the detection of primary tumors. This chapter gives a brief introduction to the syndrome of CUP, followed by an outline of the rationale, use, and utility of FDG-PET/CT in CUP, and concludes with a discussion on the challenges and future directions in the diagnostic management of patients with CUP.

Unknown primary tumors

An unknown primary tumor (UPT) is defined by the presence of a metastatic cancer without a known primary site of origin despite a standardized diagnostic workup. Clinically, UPTs show rapid progression and early dissemination, with signs and symptoms related to the metastatic site. The molecular bases of their biology remain largely unknown, with no evidence as to whether they represent a distinct biological entity. Immunohistochemistry remain the best diagnostic tool in term of cost-effectiveness, but the time-consuming "algorithmic process" it relies on has led to the application of new molecular techniques for the identification of the primary site of UPTs. For example, several microarray or miRNA classifications of UPTs have been used, with an accuracy in the prediction of the primary site as high as 90%. It should be noted that validating a prediction of tissue origin is challenging in these patients, since most of them will never have a primary site identified. Moreover, prospective studies to determine whether selection of treatment options based on such profiling methods actually improves patient outcome are still missing. In the last few years functional imaging (i.e. FDG-PET/CT) has gained a main role in the detection of the site of origin of UPTs and is currently recommended by the European Association of Nuclear Medicine. However, despite recent refinements in the diagnostic workup, the site of origin of UPT often remains elusive. As a consequence, treatment of patients with UPT is still empirical and inadequate.

Positron emission tomography scan reveals an unusual source for cervical lymphadenopathy: right colon cancer

Cervical lymphadenopathy is usually related to the presence of an inflammatory disease or to a malignant localization. In the event of metastatic findings, the thyroid gland is the most likely primary site of a tumor. Metastatic lymphadenopathy represents a challenge when the primary tumor is unknown. A 64-year-old female with a supraclavicular palpable mass in the absence of underlying thyroid disease underwent ultrasonography of the neck, biopsy of the pathological lymph node, fluorodeoxyglucose-Positron Emission Tomography (FDG-PET) and colonoscopy until right colon cancer was diagnosed. FDG-PET is a fast and reliable tool to discover the primary site of cervical masses of unknown origin.

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.

Capecitabine and oxaliplatin as second-line treatment in patients with carcinoma of unknown primary site

BACKGROUND

Treatment of patients with carcinoma of unknown primary site (CUP) remains a challenge, and no effective second-line treatment has been identified. In CUP patients who are non-responsive or relapse early after first-line platinum/taxane-based regimens, it is likely that gastrointestinal (GI) tract tumours may be overrepresented. These patients could be candidates for GI tract-directed therapy. We here report the results obtained with oxaliplatin and capecitabine as second-line therapy in 25 recurrent/refractory CUP patients following first-line treatment with paclitaxel, cisplatin and gemcitabine.

PATIENTS AND METHODS

Patients received capecitabine orally (1000 mg/m(2)) twice daily, days 1-14, and oxaliplatin (130 mg/m(2)) intravenously on day 1 in a three-week schedule.

RESULTS

Twenty-five CUP patients received a median of three cycles of capecitabine and oxaliplatin as second-line treatment. Histopathological assessments suggested the primary site to be of GI tract origin in the majority of the patients (76%). We found an objective response rate of 13%, a median progression-free survival and overall survival rate of 2.3 and 3.9 months, respectively, and 32% of patients alive at one year after initiation of second-line therapy. The regimen was well tolerated by most patients.

CONCLUSIONS

This study, demonstrates that there is still a significant need for improved second-line therapy in CUP patients.

Paclitaxel, cisplatin and gemcitabine in treatment of carcinomas of unknown primary site, a phase II study

BACKGROUND

The present study was conducted to evaluate the efficacy and toxicity of a combination of paclitaxel, cisplatin and gemcitabine in patients with carcinoma of unknown primary site (CUP).

PATIENTS AND METHODS

Patients with CUP, ECOG performance status 0-1 and age between 18 and 65 years old were treated with paclitaxel 175 mg/m(2) day 1, cisplatin 75 mg/m(2) day 1 and gemcitabine 1000 mg/m(2) day 1 and 8 in a three-week schedule.

RESULTS

Ninety-eight patients were enrolled between 1998 and 2008. Ninety-one patients had target lesions according to the RECIST guidelines. The overall response rate was 42.9% (39 patients), including five complete responses (5.5%) and 34 partial responses (37.4%). The median survival time was 10.7 months, and the survival rates at one and two years were 42% and 14%, respectively. The most frequent grade 3 or more adverse events were neutropenia and thrombocytopenia. There were 3 treatment-related deaths.

CONCLUSIONS

Combination of paclitaxel, cisplatin and gemcitabine is an active regimen in patients with CUP with response and survival rates at least similar to other platinum- and taxane-containing regimens. The treatment was well tolerated by most patients although neutropenia and thrombocytopenia were relatively common. The present regimen represents an attractive regimen in younger CUP patients with a good performance status.

A case of long-term recurrence-free poorly differentiated neuroendocrine carcinoma of lymph nodes treated by surgical resection without any chemotherapy

A 77-year-old man presented with a 2-month history of an enlarged right inguinal lymph node. Diagnostic excisional biopsy of the inguinal lymph node proved it to be a poorly differentiated neuroendocrine carcinoma by histological and immunohistological analyses. We diagnosed a poorly differentiated neuroendocrine carcinoma by histological examination and immunohistological analysis of the resected inguinal lymph node. We performed computed tomographic examination and positron emission tomography, which identified lymph node involvement without any signs of other tumors. Because these tumors had grown expandingly and had been encapsulated locally, we performed an operation to dissect all of the involved lymph nodes. Direct invasion to the right external iliac artery was not detected, and two of the enlarged lymph nodes were successfully resected without any complications. Pathologically, the resected specimen was diagnosed as a neuroendocrine carcinoma with a negative surgical margin and it was similar to the histology of the inguinal lymph node previously resected. The patient had no recurrence for 3 years without receiving any adjuvant treatment. There have been no reports describing a case of poorly differentiated neuroendocrine carcinoma, of unknown origin, which metastasized to other lymph nodes. Although further studies are required, complete resection of the involved lymph nodes should be considered as a choice for localized, expanding growth-pattern disease even if it is undifferentiated type.

Cancer patients without a known primary: incidence and survival trends in Sweden 1960-2007

BACKGROUND

Metastatic cancer from an unknown primary tumour (CUP) is a common and heterogeneous clinical entity. In Sweden like in many other countries, the continuum of care for such patients remains to be established.

MATERIAL AND METHODS

Data on CUP cases reported to the Swedish Cancer Registry during 1960 through 2007 was used to assess time trends for incidence, survival, and histological tumour type.

RESULTS

There was an upward trend for the age-adjusted incidence until the late 1990s. This roughly paralleled the increase for all reported cancers during the same period. The increase of CUP mainly concerned patients aged above 50 years, and tumours classified as adenocarcinomas. The relative survival at 12 months after a diagnosis of CUP was estimated at 20%. However, after 12 months the relative survival levelled of and the 5-year estimate was 10-15% which suggests that a small proportion of CUP cases may be cured. Relative survival was highly dependent on age with substantially better outcome for young patients, particularly those aged below 30 years. We observed no time trend for survival.

DISCUSSION

Cases diagnosed as CUP includes patients with metastatic spread from a wide variety of tumours although certain tumour types probably are overrepresented, for example, cancers in sites that are difficult to examine clinically. Incidence trends probably represent the sum of trends for these cancers as well as diagnostic trends. The decreased incidence observed during the last decade might thus be explained in terms of a combination of improved diagnostic methods to detect primary tumours and decreasing incidence for e.g. pancreatic cancer and lung cancer among males. There is a need of evidence-based programs that define the continuum of care for CUP patients. Such a program is currently being developed through collaboration between all health care regions in Sweden.

Phase II trials in patients with carcinoma of unknown primary: a pooled data analysis

BACKGROUND

The management of carcinoma of unknown primary site remains debatable. The literature data consists of about 29 phase-II studies investigating 38 regimens, providing a broad range of response rates (RR).

METHODS

We performed a pooled published data analysis to identify the factors influencing RR in these 29 studies.

RESULTS

In front-line treatment, the overall RR was 31% (430/1,380). At least nine factors significantly influenced the reported RR, excluding drugs under investigation, such as the impact factor of the journal, single-centre study, some eligibility criteria, central radiological review, sample size calculation based on statistical hypothesis and stratification. Two drugs seem to improve RR: cisplatin and doxorubicin. Two drugs seem to be associated with a worse RR: irinotecan and carboplatin.

CONCLUSIONS

This pooled data analysis illustrates that in a phase II trial setting, it is impossible to attribute the variation in RR solely to the modification of drugs under investigation.