Epidemiology of unknown primary tumours

Diagnosis of unknown primary cancer based on molecular techniques may influence therapeutic approach and improve survival

Unknown primary cancer (UPC) is a common clinical syndrome classically associated with a poor prognosis. Pathological examination including immunohistochemistry continues to be essential in tumour origin characterization, although in many cases primary tumour site remains unknown. Gene expression based analysis may offer important diagnostic information that could lead to therapeutic decisions.

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.

Role of 2-deoxy-2-[F-18] fluoro-D-glucose positron emission tomography in the management of bone and soft-tissue metastases

We retrospectively reviewed 71 histopathologically-confirmed bone and soft-tissue metastases of unknown origin at presentation. In order to identify the site of the primary tumour all 71 cases were examined with conventional procedures, including CT, serum tumour markers, a plain radiograph, ultrasound examination and endoscopic examinations, and 24 of the 71 cases underwent 2-deoxy-2-[F-18] fluoro-D-glucose positron emission tomography (FDG-PET). This detected multiple bone metastases in nine patients and the primary site in 12 of the 24 cases; conventional studies revealed 16 primary tumours. There was no significant difference in sensitivity between FDG-PET and conventional studies. The mean maximal standardised uptake value of the metastatic tumours was significantly higher than that of the primary tumours, which is likely to explain why FDG-PET did not provide better results. It was not superior to conventional procedures in the search for the primary site of bone and soft-tissue metastases; however, it seemed to be useful in the staging of malignancy.

Diagnosis of metastatic neoplasms: molecular approaches for identification of tissue of origin

CONTEXT

Tumors of uncertain or unknown origin are estimated to constitute 3% to 5% of all metastatic cancer cases. Patients with these types of tumors show worse outcomes when compared to patients in which a primary tumor is identified. New molecular tests that identify molecular signatures of a tissue of origin have become available.

OBJECTIVE

To review the literature on existing molecular approaches to the diagnosis of metastatic tumors of uncertain origin and discuss the current status and future developments in this area.

DATA SOURCES

Published peer-reviewed literature, available information from medical organizations (National Comprehensive Cancer Network), and other publicly available information from tissue-of-origin test providers and/or manufacturers.

CONCLUSIONS

Molecular tests for tissue-of-origin determination in metastatic tumors are available and have the potential to significantly impact patient management. However, available validation data indicate that not all tests have shown adequate performance characteristics for clinical use. Pathologists and oncologists should carefully evaluate claims for accuracy and clinical utility for tissue-of-origin tests before using test results in patient management. The personalized medicine revolution includes the use of molecular tools for identification/confirmation of the site of origin for metastatic tumors, and in the future, this strategy might also be used to determine specific therapeutic approaches.

Rare form of extraovarian peritoneal serous papillary carcinoma with solitary tumor in the abdominal wall: a case report and literature review

Cases of cancer presenting with microscopically confirmed metastatic malignancies for which no primary site can be detected are a challenge to stage clinically. Adenocarcinoma of unknown primary site is a subtype with high frequency that has no standard treatment and a poor prognosis. A 32-year-old female was found to have a tumor in the abdominal wall. Tumorectomy was conducted. A pathological examination indicated serous papillary adenocarcinoma, and peritoneal or ovarian cancer was suspected. Exploratory laparotomy and partial resection of the ovaries were carried out, but there were no malignant findings in the peritoneum, ovarian tissue or ascitic fluid. This is an extremely rare case of serous papillary adenocarcinoma with a cystic tumor that was categorized as extraovarian peritoneal serous papillary carcinoma (EPSPC) without other clinical findings.

Large mass affecting retroperitoneal great vessels: a rare presentation of a cancer of unknown primary with diagnostic dilemma and challenged surgical intervention

INTRODUCTION

Cancers of unknown primary site (CUPs) consist of a clinical entity which accounts for 3-5% of all solid tumor patients. They are metastatic solid tumors whose fundamental characteristic is the absence of identifiable site of the primary tumor.

CASE REPORT

We report the case of a completely asymptomatic 34-year-old man with a palpated huge mass found incidentally in the left abdomen. All the investigations were normal. During the operation, a large mass was identified 2 cm below the left renal artery which was displacing and encompassing the great retroperitoneal vessels and the left ureter. A complete resection of the mass was performed while the histological examination revealed a solitary retroperitoneal lymph node categorized as metastatic adenocarcinoma of unknown primary site.

CONCLUSION

It is essential to assess the high incidence of patients with cancer who present with CUP. Early surgical excision of the metastatic lesion followed by adjuvant combination chemotherapy should be considered for patients with only a single site of malignancy.

Paclitaxel and carboplatin vs gemcitabine and vinorelbine in patients with adeno- or undifferentiated carcinoma of unknown primary: a randomised prospective phase II trial

Platinum/taxane combinations are widely used in patients with carcinoma of unknown primary (CUP), yielding response rates of 30% and median overall survival of 9-11 months in selected patients. Yet these combinations have not been subject to a randomised trial to overcome selection bias, a major problem in CUP. We randomised 92 patients to either paclitaxel/carboplatin (arm A) or the non-platinum non-taxane regimen gemcitabine/vinorelbine (arm B). The primary endpoint was rate of practicability as defined: application of >or=2 cycles of therapy (1) with a maximal delay of 1 week (2) and survival of >or=8 months (3). Practicability was shown in 52.4% (95% CI 36-68%) in arm A and in 42.2% (95% CI 28-58%) in arm B, respectively. The median overall survival, 1-year survival -rate and response rate of patients treated in arm A was 11.0 months, 38, and 23.8%, arm B 7.0 months, 29, and 20%. In conclusion, the paclitaxel/carboplatin regimen showed clinically meaningful activity in this randomised trial (Clinical trial registration number 219, 'Deutsches KrebsStudienRegister', German Cancer Society.)

Carcinoma of unknown primary (CUP)

Carcinoma of unknown primary (CUP) is one of the 10 most frequent cancers worldwide. It constitutes 3-5% of all human malignancies. Patients with CUP present with metastases without an established primary site. CUP manifests as an heterogeneous group of mainly epithelial cancers recognised by distinct clinicopathological entities. The diagnostic work-up includes extensive histopathology investigations and modern imaging technology. Nevertheless, the primary tumour remains undetected most of the time. Molecular diagnosis with DNA microarrays demonstrates high sensitivity, but its prognostic contribution is still uncertain. Certain clinicopathological CUP entities are considered as favourable sub-sets responding to systemic platinum-based chemotherapy or managed by locoregional treatment. These sub-sets are: the poorly differentiated carcinomas involving the mediastinal-retroperitoneal nodes, peritoneal papillary serous adenocarcinomatosis in females, poorly differentiated neuroendocrine carcinomas, isolated axillary node adenocarcinomas in females or cervical nodal involvement by a squamous cell carcinoma. Patients who belong to the non-favourable sub-sets have a worse prognosis.

Cadherin-17 is a useful diagnostic marker for adenocarcinomas of the digestive system

Cadherin-17, also called liver-intestine cadherin, is a calcium-dependent transmembrane glycoprotein that mediates cell-cell adhesion in intestinal epithelium. Expression of cadherin-17 was reported in gastric, pancreatic, and colorectal adenocarcinomas but not in other tumors. Whether cadherin-17 can be used as a marker for diagnosis of cancers is still unclear. In this study, we used immunohistochemical methods to stain cadherin-17 in tissue arrays containing most normal tissues and 518 carcinomas from many anatomic sites. Among normal tissues, the expression of cadherin-17 was limited to epithelial cells of small intestine and colon. Colorectal adenocarcinomas showed staining in 96% of cases and most of them had strong and diffuse staining. Gastric, pancreatic, and biliary adenocarcinomas showed diffuse or scattered staining in about 25-50% of cases. Fewer than 1% of carcinomas outside the digestive system were positive for cadherin-17. When a two-marker, Cadherin-17/cytokeratin 7, profile was used, 37 of 38 (97%) cadherin-17(+)/cytokeratin 7(-) tumors were colorectal adenocarcinomas; 49 of 56 (86%) cadherin-17(+)/cytokeratin 7(+) tumors were gastric, pancreatic, or biliary adenocarcinomas. Our results show that cadherin-17 is a useful immunohistochemical marker for diagnosis of adenocarcinomas of the digestive system.

Exploring the epidemiological characteristics of cancers of unknown primary site in an Australian population: implications for research and clinical care

OBJECTIVES

To investigate incidence, mortality and case survival trends for cancer of unknown primary site (CUP) and consider clinical implications.

METHOD

South Australian Cancer Registry data were used to calculate age-standardised incidence and mortality rates from 1977 to 2004. Disease-specific survivals, socio-demographic, histological and secular predictors of CUP, compared with cancers of known primary site, and of CUP histological types, using multivariable logistic regression were investigated.

RESULTS

Incidence and mortality rates increased approximately 60% between 1977--80 and 1981--84. Rates peaked in 1993--96. Male to female incidence and mortality rate ratios approximated 1.3:1. Incidence and mortality rates increased with age. The odds of unspecified histological type, compared with the more common adenocarcinomas, were higher for males than females, non-metropolitan residents, low socio-economic areas, and for 1977--88 than subsequent diagnostic periods. CUP represented a higher proportion of cancers in Indigenous patients. Case survival was 7% at 10 years from diagnosis. Factors predictive of lower case survival included older age, male sex, Indigenous status, lower socio-economic status, and unspecified histology type.

CONCLUSION

Results point to poor CUP outcomes, but with a modest improvement in survival. The study identifies socio-demographic groups at elevated risk of CUP and of worse treatment outcomes where increased research and clinical attention are required.

Metastases in the Absence of a Primary Tumor: Advances in the Diagnosis and Treatment of CUP Syndrome

INTRODUCTION

The term cancer of unknown primary site (CUP) syndrome is used to describe malignancies in which a complete diagnostic work-up detects metastases in the absence of an identifiable primary tumor.

METHODS

Based on a selective literature review, national and international guidelines, and the experience of the "Arbeitskreis CUP-Syndrom der Arbeitsgemeinschaft Internistische Onkologie der Deutschen Krebsgesellschaft" (CUP Syndrome Committee of the Medical Oncology Joint Working Group of the German Cancer Society), developments in the diagnosis and treatment of CUP syndrome are reported.

RESULTS

Most patients diagnosed with CUP have an unfavorable prognosis, with a life expectancy of less than 12 months. Nevertheless, it is important to identify subsets of patients in whom specific treatment offers the chance of long-term survival or even full recovery.

DISCUSSION

Only rigorous further development of diagnostic tools and treatment protocols will enable an improvement of the poor prognosis of patients with CUP syndrome. Specific molecular treatment strategies have shown promising results.

Liver metastases from cancer of unknown primary (CUPL): a retrospective analysis of presentation, management and prognosis in 49 patients and systematic review of the literature

AIM

Patients with liver metastases from cancer of unknown primary (CUPL) have a dismal prognosis. We retrospectively analysed their management and outcome and performed a systematic review of CUPL series published in the literature.

PATIENTS AND METHODS

Electronic data from 49 CUPL patients referred to Hellenic Cooperative Oncology Group (HeCOG) centers were retrospectively studied for characteristics of clinical presentation, diagnostic workup, management, outcome and prognostic factors. A systematic literature review was undertaken in PubMed and EmBase databases.

RESULTS

All our patients (males: 31, females: 18; median age: 65) underwent a computed tomography scan (CT) of the abdomen, 71% a thoracic CT, 53% gastroscopy and 47% colonoscopy. The commonest histologic subtypes encountered were adenocarcinoma (N=34) or undifferentiated carcinoma (N=12). The liver was the only metastatic site in 38% of patients, while it was accompanied with other metastatic sites in 62% (the commonest: lung, bone and lymph nodes). Forty-seven patients received first-line chemotherapy (42 platinum based) and 16 second-line. An objective response was observed in six patients (12%), median survival being 10 months (95% CI, 7-13). In univariate analysis, good performance status and normal baseline serum CEA levels were correlated with superior survival, while in multivariate analysis only age<55 (HR 0.16, p=0.02) and the absence of extrahepatic disease (HR 0.21, p=0.007) predicted for a better outcome. Published data from four relevant series (total patients=662) parallel our findings.

CONCLUSIONS

Patients with liver metastases from CUP are resistant to conventional types of treatment and carry a poor prognosis. Understanding the molecular biology of CUP is essential for the development of new, targeted effective therapies.

Carcinoma of Unknown Primary - an Orphan Disease?

Carcinoma of unknown primary (CUP) is an intriguing clinical finding that is defined as biopsy-proven metastasis from a malignancy in the absence of an identifiable primary site after a complete clinical work-up. CUP is a relatively common clinical entity, accounting for approximately 3-5% of all cancer diagnoses, and consists of a heterogeneous group of tumors that have acquired the capacity to metastasize before the development of a clinically evident primary lesion. Notable advances have been made over the past years in the treatment of well-defined clinical subgroups of CUP, such as women with peritoneal carcinomatosis and young adults with poorly differentiated carcinomas of midline distribution, but for the majority of patients, the prognosis still remains poor. In this review, we highlight recent advances in the diagnosis and treatment of patients with CUP syndrome, and emphasize the importance of identifying several favorable subsets of CUP, amenable to specific treatment options. In addition, we will point out novel diagnostic and therapeutic approaches which will hopefully improve both our understanding and the prognosis of this more or less neglected disease.

Time trends in incidence and prognosis of primary liver cancer and liver metastases of unknown origin in a Danish region, 1985-2004

OBJECTIVES

Changes, over the last 20 years, in the diagnostic procedures and treatment of primary liver cancer (PLC) and liver metastases of unknown origin (LMUO) may have affected the clinical course of both cancers. Few longitudinal studies examined this issue. In a population-based setting, we studied changes in the incidence and prognosis of PLC and LMUO over time.

METHODS

Between 1985 and 2004, we identified 2675 patients with PLC and LMUO in three Danish counties, with a population of 1.4 million. We computed the standardized incidence rate (SIR), ratio of PLC to LMUO diagnoses, median survival, and estimated mortality rate ratio adjusted for age, sex, and comorbidity.

RESULTS

The SIR of PLC increased from 3.2 in 1985 to 5.0 in 2003, and the SIR of LMUO increased from 3.7 to 6.4. No increase was noted in the PLC-to-LMUO ratio over time (P=0.1 for trend). From 1985 to 2004, the median survival of PLC patients increased from 1.6 to 2.9 months whereas that of LMUO patients decreased from 1.7 to 1.3 months. Adjusting for age, sex, and comorbidity did not affect the mortality rate ratio estimates.

CONCLUSIONS

The incidence of both PLC and LMUO increased over time, whereas the PLC-to-LMUO ratio remained unchanged. Median survival of PLC patients has increased whereas that of LMUO patients remained practically unchanged.

Multicenter phase-II trial of irinotecan plus oxaliplatin [IROX regimen] in patients with poor-prognosis cancer of unknown primary: a hellenic cooperative oncology group study

BACKGROUND

Cancer of unknown primary (CUP) lacks established therapy although it affects 3% of cancer patients. We evaluated the irinotecan-oxaliplatin combination (IROX regimen) in previously untreated patients with non-favorable subsets of unknown primary carcinomas.

METHODS

This was a multicenter phase-II trial. Protocol treatment consisted of oxaliplatin 80 mg/m(2) followed by irinotecan 160 mg/m(2) administered every 3 weeks. The primary end points were response rate and toxicity, and secondary end points were time to progression and survival.

RESULTS

Forty-seven patients with liver, bone or multiple visceral metastases entered into the trial and received a median 6 chemotherapy cycles (1-11). The regimen was very well tolerated with one febrile neutropenia case and six cases with diarrhea grade 3 (16%). In intent-to-treat analysis the tumor response rate was 13% (95% CI = 4.8-25.7%) and 12 patients (27%, 95%CI 13.9-40.4%) had at least 4 months' duration of disease stabilization. The median time to progression was 2.7 months and the median survival was 9.5 months, with 40% of patients alive at 1 year.

CONCLUSIONS

The IROX regimen demonstrated similar efficacy and a favorable toxicity profile compared to other more toxic chemotherapy combinations in patients with poor-prognosis CUP.

Cancer of unknown primary site: missing primary or missing biology?

Cancer of unknown primary site (CUP) ranks as the fourth most common cause of cancer deaths and represents both a diagnostic and a management challenge. In CUP, the regression or dormancy of the primary tumor, the development of early, uncommon, systemic metastases, and the resistance to therapy are hallmarks of this heterogeneous clinical entity. Still, no consensus exists on whether CUP is simply a group of metastatic tumors with unidentified primaries or a distinct entity with specific genetic/phenotypic aberrations that define it as "primary metastatic disease." In this review, we present karyotypic analyses as well as the single-gene, single-protein studies done on the expression of oncogenes, tumor- or metastasis-suppressor genes, as well as angiogenesis effectors. These studies show frequent expression of oncoproteins, lack of activating epidermal growth factor receptor/c-Kit mutations or amplification, uncommon presence of tumor- or metastasis-suppressor gene mutations and highly active angiogenesis in CUP. Informative as they may be, these data have been observed in several solid tumors of known primary and failed to identify a CUP-specific molecular signature. The latter, if it exists, probably consists of a multigene expression pattern not captured by single-gene studies. Gene and protein microarray technologies offer promise for the unraveling of complex genetic programs that would either identify each CUP's primary tissue of origin or instead define the CUP-specific molecular signature. Confirmation of one of the two hypotheses would either improve primary disease-oriented therapy or develop CUP-oriented treatments targeting molecular aberrations that drive neoplastic growth/dissemination.

Prognostic and diagnostic accuracy of [18F]FDG-PET/CT in 190 patients with carcinoma of unknown primary

PURPOSE

The aim of the study was to determine the accuracy of [(18)F]fluorodeoxyglucose (FDG) PET/CT in the search for the primary and the presence of a malignancy. The prognostic value of FDG-PET/CT information was tested.

METHODS

A total of 190 patients were retrospectively analysed: 82 with histologically proven metastases (HPM) and 108 with clinical suspicion of the presence of a malignancy (CSM). The sensitivity and specificity were determined. Overall survival was calculated to evaluate the prognostic value of the FDG-PET/CT findings.

RESULTS

In the search for the primary, the sensitivity and specificity were 62.0% and 81.9%, respectively. In the search for the presence of a malignancy, the sensitivity and specificity were 93.6% and 85.7%, respectively. Between the HPM and CSM groups, no significant difference in sensitivity and specificity was found either in the search for the primary or in the search for the presence of a malignancy. No significant difference in the sensitivity and specificity was found between 78 patients who were investigated by contrast-enhanced FDG-PET/CT and the remaining patients. A significantly shorter overall survival was found among patients with positive FDG-PET/CT findings compared with patients with negative findings (p = 0.00001); no significant difference in survival was found between the HPM and the CSM group (p = 0.770).

CONCLUSION

FDG-PET/CT imaging is very helpful in the search for the presence of a malignancy in patients with carcinoma of unknown primary syndrome. FDG-PET/CT is less accurate in identifying exactly the site of a primary. Discovery of a hypermetabolic lesion was associated with the worst survival rate.

A patient with pulmonary lymphangitic carcinomatosis successfully treated with TS-1 and cisplatin

A 37-year-old man was referred to our hospital with complaints of dyspnea and general fatigue. Chest radiograph and CT scan revealed thickness of bronchovascular bundles in both lungs. In spite of various examinations, the primary lesion was not identified. He received chemotherapy containing TS-1 and cisplatin. Pulmonary lymphangitic carcinomatosis disappeared and the patient achieved a good partial response. He survived for 14 months after the chemotherapy. We believe the combination of TS-1 and cisplatin is one of the attractive options for patients with cancer of unknown primary site.

Cancer of unknown primary site: review of consecutive cases at the National Cancer Center Hospital of Japan

BACKGROUND

Cancer of unknown primary (CUP) is not a rare clinical entity, accounting for 3%-5% of all solid malignancies.

METHODS

We retrospectively reviewed 86 (38 male/48 female) patients with a diagnosis of CUP (exclusive of female patients with adenocarcinoma involving the axillary lymph nodes alone and patients with squamous cell carcinoma of the cervical lymph nodes) who were referred to the National Cancer Center Hospital between April 1996 and October 2002.

RESULTS

The median interval between the first visit to a local community hospital and referral to our hospital was 1 month (range, 1 to 45 months). The histological diagnosis was adenocarcinoma in 61 patients (71%), poorly differentiated carcinoma in 18 patients (21%), and squamous cell carcinoma in 4 patients (5%). Twenty-three female patients had peritoneal carcinomatosis of adenocarcinoma. Seventy-eight patients (91%) received platinum-containing chemotherapy. Sixty-one of the 86 patients (71%) were categorized as a subgroup of CUP without a specific therapy, and 55 of these 61 patients (90%) received platinum-containing regimens. The median survivals of all 86 patients and the 61 patients in the subgroup without a specific therapy in this series were 13 months and 11 months, respectively.

CONCLUSION

In this series, the survival of the patients in the CUP subgroup without a specific therapy did not seem worse than that in previous reports. Empirical chemotherapy with platinum-containing regimens may benefit some CUP patients in a subgroup without a specific chemotherapy.

Perspectives for targeted therapies in cancer of unknown primary site

Cancer of unknown primary site (CUP) ranks as the fourth most common cause of cancer deaths. Regression of the primary, early development of systemic metastases and resistance to therapy are hallmarks of this heterogeneous clinical entity. Targeted therapy offers promise for improvement of outcome of such patients, but it is currently hindered by lack of known molecular targets on which tumours are dependent for growth. In this review, we present the gene and protein profiling studies done on expression of oncogenes, tumour-suppressor genes and angiogenesis effectors and discuss the therapeutic potential of developed targeted agents. Existing data show occasional overexpression of Ras, BCL2 oncoproteins, absence of active EGFR/c-KIT/PDGFR signalling, uncommon presence of tumour-suppressor gene mutations and highly active angiogenesis in CUP. High-throughput multi-gene, multi-protein platforms offer promise for unravelling the complex molecular pathophysiology of CUP, for identification of targets suitable for modulation and ultimately hope for abrogation of its aggressive natural history.

Les carcinomes de primitif inconnu

PURPOSE

Carcinoma of unknown primary site is a common clinical syndrome, accounting for 2% of cancer patients. Diagnosis is a recurrent challenge for internists. Treatment is difficult and prognosis is still poor. This review presents one synthesis of diagnosis strategies and therapeutic trials. It envisages the interest of new molecular biology methods as well as therapeutic perspectives.

CURRENT KNOWLEDGE AND KEY POINTS

Pathologic examination completed with immunohistochemical tests, and, depending on cases, with electron microscopy, cytogenetics, and molecular biology is a key-point for diagnosis. Diagnosis work-up, based on histological type and on individualization of some clinical presentation, proceeds in three steps. Positron emission tomography is recommended when a curative treatment is planed, particularly in cases of isolated metastasis. Functional status analysed using the performance status and simple biologic parameters (serum lactate dehydrogenase, serum alkaline phosphatase) permit us to assess prognosis. Chemotherapy is offered for patients with a good general health status.

FUTURE PROSPECTS AND PROJECTS

Further evaluation of positron emission tomography, as well as cost-benefit analyses, is warranted. Further randomised trials are necessary to determine the optimal chemotherapy regimen in good-risk patients and the interest of chemotherapy in patients with poor-risk disease. Gene expression profiling and proteomic evaluation, as well as pharmacogenomic offer new investigation fields.

The influence of comorbidities, age, and performance status on the prognosis and treatment of patients with metastatic carcinomas of unknown primary site: a population-based study

BACKGROUND

The authors investigated how comorbidities, age, and performance status were related to the choice of chemotherapy and to the prognosis of patients with carcinomas of unknown primary site (CUP).

METHODS

Patients in Northern Alberta who were diagnosed with CUP during 2000 to 2003 were included (n = 389 patients). Survival was compared by age at diagnosis (ages <65 years, 65-74 years, and >75 years), comorbidity score (Adult Comorbidity Evaluation-27 [ACE-27] scores of 0-1 and >2), performance status (PS), and other explanatory variables, such as gender, histology, and site and number of metastases.

RESULTS

The median age was 68 years, and the median overall survival was 12 weeks. An ACE-27 overall comorbidity score >2 was found in 34% of patients, and a PS >2 was observed in 50% of patients. Multivariate analysis showed that patients who had a PS >/=2 and a high overall ACE-27 score had a worse prognosis. The impact of comorbidities on survival was limited to patients with low PS. Patients who were not evaluated at a cancer center were older, had a worse functional status, and had more moderate or severe comorbidities. Among the 257 patients who were evaluated at a cancer center, 108 patients received chemotherapy, and 121 patients had a good PS (0-1). Age was the only independent variable that was related to the likelihood of not receiving chemotherapy among patients who had a good PS. The median overall survival of the 121 patients who had a good PS was 317 days, and overall survival was not associated significantly with chemotherapy. A logistic regression analysis that included all patients who were evaluated at a cancer center identified young age, good PS, lymph node/pleural involvement, and few comorbidities as variables that were associated independently with receiving chemotherapy.

CONCLUSIONS

Patients with CUP who were not evaluated at a cancer center were older, had a worse functional status, and had more moderate or severe comorbidities; this referral bias largely explained the differences between data from registries and from tertiary centers. Moderate and severe comorbidities impacted survival in patients with who had a PS > or =2. An age-related decline was observed in the percentage of adults with good PS who received chemotherapy. The current results suggested that older patients with CUP were under treated and that factors other than PS were involved in the decision to use chemotherapy for the treatment of patients with CUP.

Chemotherapy for patients with two favourable subsets of unknown primary carcinoma: active, but how effective?

Carcinoma of unknown primary (CUP) is characterized by dismal patient survival. The outcome of patients with two favourable risk CUP subsets was studied. Eighty patients diagnosed with either midline lymph node metastases (n=33) or peritoneal carcinomatosis (n=47) were analysed retrospectively. The majority had poorly differentiated adenocarcinoma or undifferentiated carcinoma, treated with platinum-taxane based chemotherapy from 1996 till 2002. Females with peritoneal carcinomatosis also underwent surgical debulking. Objective tumour regression was present in 44% of patients (nodal group 30% versus peritoneal group 53%, p=0.066). Complete responses were seen more often in peritoneal carcinomatosis patients (nodal group 9%, peritoneal group 36%, p=0.008). At a median follow up of 60 months, median progression-free and overall survival were 5 and 10 months respectively in the nodal group, 7 and 15 months in the peritoneal group. Five-year survival was 7% (nodal group 0% vs. peritoneal group 10%, p=0.05). Complete responders fared better than non-CR patients. Fewer than four metastatic sites, elevated CA 125, and normal CA 19-9 levels were favourable prognostic factors for survival. Modern combination chemotherapy has satisfactory activity, with a minority of CUP patients enjoying long-term responses. Research efforts towards complete remission consolidation and molecular profiling are imperative.

Cancer of unknown primary (CUP)

Carcinoma of unknown primary (CUP) is one of the 10 most frequent cancers worldwide. It constitutes 3-5% of all human malignancies. Patients with CUP present with metastases without an established primary site. CUP manifests as an heterogenous group of mainly epithelial cancers recognised by distinct clinicopathological entities. The diagnostic work-up includes extensive histopathology investigations and modern imaging technology. Nevertheless, the primary tumour remains undetected most of the time. Certain clinicopathological CUP entities are considered as favourable subsets responding to systemic platinum-based chemotherapy or managed by locoregional treatment. These subsets are: the poorly differentiated carcinomas involving the mediastinal-retroperitoneal nodes, peritoneal papillary serous adenocarcinomatosis in females, poorly differentiated neuroendocrine carcinomas, isolated axillary node adenocarcinomas in females or cervical nodal involvement by a squamous cell carcinoma. Patients who belong to the non-favourable subsets have a worse prognosis.

Guanylyl cyclase C is a marker of intestinal metaplasia, dysplasia, and adenocarcinoma of the gastrointestinal tract

Gastrointestinal (GI) tumors continue to be major causes of cancer-related mortality, in part, reflecting metastases that escape detection by histopathology. Moreover, although approximately 10% of carcinomas arise from unknown locations, these tumors frequently originate in the GI tract. Guanylyl cyclase C (GC-C) is a receptor selectively expressed by intestinal epithelial cells whose persistent expression by colorectal carcinomas and ectopic expression by adenocarcinomas of the upper GI tract suggest its use as a marker for GI malignancies. Here, expression of GC-C protein, identified by immunohistochemistry, was examined in tissues and tumors arising from the human GI tract. Guanylyl cyclase C protein was expressed by epithelial cells from the duodenum to the rectum, but not by those in normal esophagus and stomach. Expression was retained in tubular adenomas, inflammatory bowel disease, premalignant lesions, and in primary and metastatic adenocarcinomas from the colon, including metastases to lymph nodes and liver. Moreover, GC-C was ectopically expressed in all cases of dysplasia and adenocarcinomas arising from intestinal metaplasia in esophagus and stomach. Thus, GC-C appears to be an immunohistochemical marker for identifying adenocarcinomas of unknown origin, metastases in patients undergoing staging for GI adenocarcinomas, and intestinal metaplasia, dysplasia, and tumors arising therein in the upper GI tract.

Angiogenesis in cancer of unknown primary: clinicopathological study of CD34, VEGF and TSP-1

Background

Cancer of unknown primary remains a mallignancy of elusive biology and grim prognosis that lacks effective therapeutic options. We investigated angiogenesis in cancer of unknown primary to expand our knowledge on the biology of these tumors and identify potential therapeutic targets.

Methods

Paraffin embedded archival material from 81 patients diagnosed with CUP was used. Tumor histology was adenocarcinoma (77%), undifferentiated carcinoma (18%) and squamous cell carcinoma (5%). The tissue expression of CD34, VEGF and TSP-1 was assessed immunohistochemically by use of specific monoclonal antibodies and was analyzed against clinicopathological data.

Results

VEGF expression was detected in all cases and was strong in 83%. Stromal expression of TSP-1 was seen in 80% of cases and was strong in 20%. The expression of both proteins was not associated with any clinical or pathological parameters. Tumor MVD was higher in tumors classified as unfavorable compared to more favorable and was positively associated with VEGF and negatively with TSP-1.

Conclusion

Angiogenesis is very active and expression of VEGF is almost universal in cancers of unknown primary. These findings support the clinical investigation of VEGF targeted therapy in this clinical setting.

The clinical relevance of cytokeratin phenotyping in needle biopsy of liver metastasis

Although cytokeratin (CK) phenotyping of metastatic tumors is now routine in many laboratories, the clinical relevance of the procedure has seldom been addressed. We carried out a prospective clinical study of 134 consecutive cases of metastatic adenocarcinoma of the liver diagnosed by needle biopsies stained routinely for CK20 and CK7. The most probable localization of the primary tumor, deduced from this staining pattern, was stated in the original pathology report. The present study compared this assignment with the information available at the time of interpretation of the liver biopsy, to the results of the subsequent clinical investigation, and to the officially reported cause of death as outcome. As expected, the primary tumors were localized in the colon or in the rectum in 85% (34/40) of the CK20+/CK7- metastases. The definite diagnosis remained metastatic colorectal carcinoma in 83% (15/18) of the cases with diagnosed colorectal cancer before the liver biopsy. In the cases without a known primary tumor when the liver biopsy was interpreted, primary colorectal localization was accurately predicted in 86% (19/22) of the patients. Compared to the outcome, 77% (36/47) of the CK20+/CK7+ metastases had the expected pancreaticobiliary primary localization in 83% (30/36) without any primary tumor being known at the time of interpretation of the liver biopsy. In contrast, the majority of CK20- metastatic carcinomas had an unexpected primary localization, 50% (16/32) in the CK20-/CK7+ and 60% (9/15) in the CK20-/CK7- subgroup. In addition, the origin of the liver metastasis remained unknown in 37% (12/32) of CK20-/CK7+ cases. Thus, the CK20+/CK7- phenotype indicates a colorectal origin of the liver metastasis with considerable accuracy and independently of the available clinical information. The same is true for CK20+/CK7+ metastases, which indicate primary tumor localization in the pancreas or in the biliary tree. The results in the CK20- subgroups of the liver metastases are disappointing and cannot substantially help the clinical investigation.

Diagnostic and therapeutic management of cancer of an unknown primary

Metastatic Cancer of Unknown Primary Site (CUP) accounts for approximately 3% of all malignant neoplasms and is therefore one of the 10 most frequent cancer diagnoses in man. Patients with CUP present with metastatic disease for which the site of origin cannot be identified at the time of diagnosis. It is now accepted that CUP represents a heterogeneous group of malignancies that share a unique clinical behaviour and, presumably, unique biology. The following clinicopathological entities have been recognised: (i) metastatic CUP primarily to the liver or to multiple sites, (ii) metastatic CUP to lymph nodes including the sub-sets involving primarily the mediastinal-retroperitoneal, the axillary, the cervical or the inguinal nodes, (iii) metastatic CUP of peritoneal cavity including the peritoneal papillary serous carcinomatosis in females and the peritoneal non-papillary carcinomatosis in males or females, (iv) metastatic CUP to the lungs with parenchymal metastases or isolated malignant pleural effusion, (v) metastatic CUP to the bones, (vi) metastatic CUP to the brain, (vii) metastatic neuroendocrine carcinomas and (viii) metastatic melanoma of an unknown primary. Extensive work-up with specific pathology investigations (immunohistochemistry, electron microscopy, molecular diagnosis) and modern imaging technology (computed tomography (CT), mammography, Positron Emission Tomography (PET) scan) have resulted in some improvements in diagnosis; however, the primary site remains unknown in most patients, even on autopsy. The most frequently detected primaries are carcinomas hidden in the lung or pancreas. Several favourable sub-sets of CUP have been identified, which are responsive to systemic chemotherapy and/or locoregional treatment. Identification and treatment of these patients is of paramount importance. The considered responsive sub-sets to platinum-based chemotherapy are the poorly differentiated carcinomas involving the mediastinal-retroperitoneal nodes, the peritoneal papillary serous adenocarcinomatosis in females and the poorly differentiated neuroendocrine carcinomas. Other tumours successfully managed by locoregional treatment with surgery and/or irradiation are the metastatic adenocarcinoma of isolated axillary nodes, metastatic squamous cell carcinoma of cervical nodes, or any other single metastatic site. Empirical chemotherapy benefits some of the patients who do not fit into any favourable sub-set, and should be considered in patients with a good performance status.