Metastatic adenocarcinoma of unknown primary site. A randomized study of two combination chemotherapy regimens

Redefining cancer of unknown primary: Is precision medicine really shifting the paradigm?

The concept of Cancer of Unknown Primary (CUP) has evolved with the advent of medical oncology. CUP can be difficult to diagnose and represents 2 to 5% of new cancers, therefore not exceptionally rare. Within CUPs can be identified a subset of favourable prognosis tumours, however the vast majority of CUP patients belongs to a poor prognosis group. CUP features significant oncological challenges, such as unravelling biological and transversal issues, and most importantly, improving patient's outcomes. In that regard, CUP patients' outcomes regrettably showed minimal improvement for decades and CUP remains a cancer group of very poor prognosis. The biology of CUP has two main hypotheses. One is that CUP is a subgroup of a given primary cancer, where the primary is present but cannot be seen due to its small size. The other, the "true" CUP hypothesis, states that CUP share features that make them a specific entity, whatever their tissue of origin. A true biological signature has not yet been described, but chromosomal instability is a hallmark of poor prognosis CUP group. Precision oncology, despite achieving identifying the putative origin of the CUP, so far failed to globally improve outcomes of patients. Targeting molecular pathways based on molecular analysis in CUP management is under investigation. Immunotherapy has not shown ground-breaking results, to date. Accrual is also a crucial issue in CUP trials. Herein we review CUP history, biological features and remaining questions in CUP biology, the two main approaches of molecular oncology in CUP management, in order to draw perspectives in the enormous challenge of improving CUP patient outcomes.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

[Structured diagnostics and therapy of the CUP syndrome]

BACKGROUND

In the majority of cases, patients with cancer of unknown primary (CUP) have a poor prognosis with no prospect of being cured. Hence, a reasonable focus of diagnostics on its essential targets seems appropriate.

PATIENTS

Particularly important is the identification of all patients who can be assigned to subgroups with a favorable prognosis and who might benefit from a specific therapy. For all other patients, platinum-based combination therapy is the standard cytostatic therapy.

THERAPY

In addition to platinum derivatives, taxanes, gemcitabine and irinotecan can also be used. Promising innovative approaches include targeted therapies, in particular bevacizumab and erlotinib, and identification of the tissue origin with micro-RNA or gene expression analyses which can help identify the most suitable organ-specific therapy for individual patients.

PERSPECTIVES

It would be desirable if the group of patients treated with unspecific therapy could be reduced by improved diagnostics so that these patients could be treated with organ-specific therapy or with molecularly targeted approaches. Micro-RNA and gene expression analyses appear to be interesting for this purpose. Another complementary approach is to improve the treatment results of patients receiving an unspecific standard combination therapy by additional administration of new targeted substances.

Carcinomas of an unknown primary origin--diagnosis and treatment

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

Gemcitabine and cisplatin in patients with carcinoma of unknown primary site

The optimal therapy for carcinoma of unknown primary site (CUPS) is still under investigation. In this retrospective trial, we reported the response rates and overall and progression free survival of 23 CUPS patients that were treated with gemcitabine and cisplatin. The mean age of the patients was 54.95 (32-77). Sixteen (69.6%) of them were males and 7(30.4%) females. Totally 109 cycles with a mean of 6 were administered. Thirteen of 23 patients (56.5%) presented with only one metastatic site, and the liver is the most frequent metastatic site (39.1%). Histologic types were adenocarcinoma in 14 patients (60.8%), squamous carcinoma in 1 patient (4.8%), epithelioid cancer in 3 patients (13%) and undifferentiated cancer in 5 patients (21.7%). Three patient achieved a CR (13%), 4 patients achieved a PR (17.4%) and 8 patients had SD (34.8%) with an overall 30.4% response rate. However, 8 patients had progressive disease with a percentage of 34.8%. The median follow-up time was 10 months (3-42 months). The mean and median survival was 12.5 (3-42) months and 10 months (range, 3-42 months) and progression free survival was 5.5 months (range, 0-23 months). Gemcitabine plus cisplatin may be an effective treatment of CUPS. Therefore additional trials are needed especially with new chemotherapeutics.

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.

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.

Infusional 5-fluorouracil and cisplatin as first-line chemotherapy in patients with carcinoma of unknown primary site

A combination chemotherapy of 5-fluorouracil (5-FU) and cisplatin (CDDP) has demonstrated activities in various malignancies, including head and neck, lung, esophageal, gastric, and pancreatic cancers. We reviewed our experience of 11 patients diagnosed as carcinoma of unknown primary site (CUPS), who were treated with infusional 5-FU and CDDP between January 1998 and December 2005. The median number of cycles administered was three (range: 1-12). All patients had measurable disease. Six partial responses were obtained (response rate: 54.5%, 95% confidence interval: 23.4-83.3%). The median survival time for all patients was 10 mo (range, 2-37 mo). The median time to disease progression was 3 mo (range, 1-6 mo). This regimen was well tolerated, with grade 3-4 neutropenia (two patients), febrile neutropenia (one patient), grade 3 nausea/vomiting (one patient), and grade 3 stomatitis (two patients). Grade 2 leukoencephalopathy was observed in one patient. No treatment-related death was observed. The combination chemotherapy of infusional 5-FU and CDDP was feasible and tolerated with promising activity for CUPS.

Forty years experience of treating cancer of unknown primary

Cancer of unknown primary site (CUP) is not a rare tumour. It accounts as the seventh to eighth most frequently diagnosed cancer in a general medical oncology service. Since CUP is not a homogeneous disease and it consists of different favourable and unfavourable sub-sets, treatment of each clinicopathological entity requires a unique approach. The spectrum of therapeutic management includes both locoregional and systemic therapy and should intend to offer optimal benefit to favourable CUP patients and palliative care to unfavourable cases. This review article provides both a historical outline of CUP treatment as well as a helpful therapeutic guide to every oncologist who treats CUP patients.

A Clinical Review of the Investigation and Management of Carcinoma of Unknown Primary in a Single Cancer Network

AIMS

Carcinoma of unknown primary (CUP) is a common encounter in oncological practice and represents 2.0-6.0% of all invasive malignancies. Evidence to support particular therapeutic strategies in this patient population is scarce, and empirical therapies are frequently derived from research on patients where the primary tumour site is known.

MATERIALS AND METHODS

This retrospective study reviewed the management of all patients recorded to have a diagnosis of CUP in a single cancer centre over a period of 12 months. Health records were reviewed documenting the CUP subtype, the investigations carried out both in the referring cancer unit and subsequently at the cancer centre and the recommended treatment (type and regimen), together with survival. The outcomes were examined in respect to a number of prognostic factors. Statistical tests were considered significant at P < 0.05.

RESULTS

One hundred and sixty-six patients were recorded to have a diagnosis of CUP, representing 3.7% of all referrals to the cancer centre. The median age of patients was 68 years (range 32-94 years), and 52.0% were women. The three most common CUP subgroups were CUP-liver/multiple sites (25.0%), CUP-bone (21.0%) and CUP-brain (16.0%). The remaining subgroups occurred at frequencies of less than 10% each. Histological confirmation was only obtained in 55.0% of cases. Even within a single subtype, 41 patients with CUP-liver/multiple sites underwent a total of 19 different investigations before any treatment being given. Forty-seven (28.0%) patients received radiotherapy, 30 (18.0%) received chemotherapy and 58 (35.0%) received supportive care alone. Nine different 5-fluorouracil-containing regimens were used in 11 patients treated with chemotherapy for CUP-liver. The overall median survival for all patients was 4.0 months. Survival was better in patients with a good performance status (0-1) and absent liver metastases (median survival 15.0 months; 95% confidence interval 8.0-22.1) and those who received chemotherapy (median survival 13.0 months; 95% confidence interval 7.4-18.6). Multivariate analysis confirmed female gender (P = 0.006), a good performance status (0/1) (P < 0.0001) and absent liver metastases (P = 0.002) as favourable prognostic indicators.

CONCLUSIONS

The appropriate management of patients with CUP is unclear and this study revealed a high degree of variation in clinical practice. This area is in urgent need of clinical research to ensure that the treatment of CUP is evidence based. Until such time, clinical recommendations are suggested for the investigation and treatment of such patients. Therapeutic progress will be facilitated by designating a clinical lead for CUP in each clinical network.

Cisplatin and gemcitabine with either vinorelbine or paclitaxel in the treatment of carcinomas of unknown primary site

BACKGROUND

: To date, the standard treatment for patients who have carcinoma of unknown primary site has not been established.

METHODS

: In this randomized Phase II study, 66 previously untreated patients (33 patients per arm) with carcinomas of unknown primary site received cisplatin (35 mg/m2) and gemcitabine (1000 mg/m2) with either paclitaxel (70 mg/m2) or vinorelbine (25 mg/m2), and all drugs were administered intravenously on Days 1 and 8 of a 21-day cycle. Twenty-nine patients (44%) presented with > or =2 involved sites. The pathologic diagnosis was mainly adenocarcinoma (48 patients; 72.7%) and squamous carcinoma (7 patients; 10.6%).

RESULTS

: In the first arm, 16 patients (48.5%) experienced an objective response, and 9 patients (27.2%) had disease stabilization. In the vinorelbine-containing arm, 14 patients (42.3%) experienced an objective response, and 8 patients (24.2%) had disease stabilization. The median response duration and the median time to progression were similar in both treatment arms; the median overall survival was 9.6 months (95% confidence interval, 7.11-12.09 months) for patients who received the cisplatin/gemcitabine/paclitaxel regimen and 13.6 months (95% confidence interval, 6.61-20.59 months) for patients who received the vinorelbine combination. Grade 3 and 4 toxicities were more frequent in the paclitaxel-containing arm.

CONCLUSIONS

: Both combinations satisfied the 2-step design, demonstrating antitumor activity without relevant differences in response rates or response duration; however, the vinorelbine-containing regimen yielded superior results both in terms of overall survival (13.6 months vs 9.6 months) and in terms of treatment tolerability. Therefore, according to a pick the winner attitude, the combination of cisplatin/gemcitabine/vinorelbine may be considered in the design of future randomized, Phase III trials for patients with carcinomas of unknown primary site.

Hepatic metastases from carcinomas of unknown primary site

AIM

Hepatic metastases are often present at diagnosis of carcinoma of unknown primary site (CUP). The objective of this study was to describe the diagnostic and therapeutic strategies used.

METHODS

One hundred and eighteen patients were treated at the Cancer Center of Montpellier from 1993 to 2002 for CUP initially metastatic to the liver. Initial characteristics, diagnostic tests, chemotherapies and outcome were retrospectively recorded.

RESULTS

The most frequent histological types observed were adenocarcinoma, undifferentiated, neuroendocrine and squamous-cell carcinomas. Hepatic metastases revealed the cancer in 66 patients and were isolated in 32 patients. Other metastatic sites involved lymph nodes, lung and bone. Pretreatment computed tomography scans of the chest, abdomen and pelvis evaluation were available for more than 80% of patients. Colonoscopy, gastroscopy and bronchoscopy were performed in 58, 56 and 26% of patients respectively. One hundred and seven patients had received at least a front-line of chemotherapy. Seventy-four patients had received platin salt-based chemotherapy, 67 in front-line treatment and 10 in second line. In first-line chemotherapy, overall response rates with or without platin were 19.4 and 20% respectively. One hundred and two of 111 deaths were due to disease progress and seven toxic-related deaths occurred. The median survival was 6.6 months, and 7.8 and 4.6 months in the with or without platin groups respectively (P=0,35). The median survival for treated patients was 7 months. Multivariate analysis identified two prognostic factors: serum lacto-dehydrogenase level and performance status.

CONCLUSIONS

According to this study, pretreatment evaluations, which were very extensive in some patients, were insufficient to identify the primary site of liver metastases. Because of the poor prognostic, chemotherapy, in absence of clinically demonstrated benefit, has to be reserved for patients with better prognosis. Prospective trials are needed to determine whether use or not of cisplatin should be proposed for standard protocols.

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.

The unknown biology of the unknown primary tumour: a literature review

The unknown primary tumour (UPT) is an intriguing clinical phenomenon found in approximately 5% of all newly diagnosed patients with cancer. It is unclear whether UPT forms a distinct biological entity with specific genetic and phenotypic characteristics, or whether it is merely a clinical presentation of metastases in patients in whom the primary tumour cannot be detected and does not result in any visible clinical signs. Understanding the basic biology of UPT may shed light on this issue and, moreover, may have a direct impact on clinical care. A review of the literature revealed only a limited number of publications describing the genetic and phenotypic features of UPT, most of which focus only on the potential of these markers to predict prognosis. The question as to whether the biology of UPT is different from tumours of known primaries therefore remains unanswered. Further insight into the molecular mechanisms underlying the oncogenesis of UPT, e.g. by applying newly available DNA and gene profiling microarray techniques, will be necessary to understand its specific biology and to develop more effective treatments.

Alternative bimonthly cycles of doxorubicin, cyclophosphamide, and etoposide, cisplatin with hematopoietic growth factor support in patients with carcinoma of unknown primary site

BACKGROUND

Because carcinomas of unknown primary origin are highly malignant tumors with a bad prognosis (median survival, 6-12 months) and no current optimal therapy, the authors designed a prospective dose-dense chemotherapy regimen with the objective of improving the results observed in patients who receive conventional treatment.

METHODS

Eighty-two patients received alternative bimonthly cycles of doxorubicin 50 mg/m(2) with cyclophosphamide 1000 mg/m(2) (AC) and etoposide 300 mg/m(2) with cisplatin 100 mg/m(2) (EP). Cycles were given at 2-week intervals with granulocyte-macrophage-stimulating factor support (5 microg/kg per day) from Day 4 to Day 10. Patients without measurable lesions were included, because the major end point was survival.

RESULTS

The median number of alternative cycles of AC and EP was 4 cycles (range, 1-12 cycles). An objective response was observed in 24 of 62 patients (39%; 95% confidence interval, 30-48%) with measurable lesions, including 6 patients who achieved a complete response. Among 20 patients with nonmeasurable disease, 9 patients (45%) had no evidence of progressive disease at the end of chemotherapy. The overall median survival of 82 patients was 10 months, with 5 patients surviving clinically disease free at 17 months, 29 months, 45 months, 64 months, and 70 months after the end of treatment. Myelosuppression was the most common toxicity. Two toxic deaths occurred.

CONCLUSIONS

Using these doses and schedules, a dose-dense chemotherapy regimen did not appear to improve the outcome of patients with carcinoma of unknown primary site. Alternative studies dealing with news drugs will be required.

Multicentric phase II study of cisplatin and etoposide in patients with metastatic carcinoma of unknown primary

The aim of this study was to determine the efficacy and toxicity of combination cisplatin and etoposide chemotherapy in patients with metastatic carcinoma of unknown primary. Patients were treated with cisplatin (100 mg/m2 iv day 1) followed by etoposide (100 mg/m2 iv days 1-3) every 3 weeks for a maximum of 6 cycles. Patients with progressive disease after two or four courses could receive FAC (fluorouracil, doxorubicin, and cyclophosphamide) until progression. Twenty-five patients were entered and were assessable for response and toxicity. Fifteen (60%) patients had adenocarcinomas. Patients received a median of four courses. Toxicity was mainly hematologic including grade III/IV neutropenia. The overall response rate was 32%. There was no complete response, 32% partial responses, 32% stable disease, and 36% disease progression. Median response duration was 4 months (range: 2-5 months). The median overall survival of the 25 patients was 8 months. No objective response could be obtained with FAC, but 33% of patients achieved stabilization of the disease for at least 3 months. This cisplatin-etoposide combination demonstrated some activity against an usually resistant disease.

Overexpression of Her-2 in patients with poorly differentiated carcinoma or poorly differentiated adenocarcinoma of unknown primary site

PURPOSE

To determine the frequency of Her-2 overexpression in patients with poorly differentiated carcinoma or poorly differentiated adenocarcinoma of unknown primary site.

PATIENTS AND METHODS

Tumor specimens from 100 patients with poorly differentiated carcinoma or poorly differentiated adenocarcinoma were stained for the Her-2 protein using the Dako immunohistochemical method. Clinical and pathologic characteristics of patients with and without Her-2 overexpression were compared.

RESULTS

Staining for Her-2 overexpression was successful in 94 of 100 patients. Ten (11%) of 94 tumor specimens overexpressed Her-2. Eight of 10 overexpressors had poorly differentiated adenocarcinoma, and all overexpressors had predominant tumor location above the diaphragm, usually in the mediastinum or lungs.

CONCLUSION

Her-2 overexpression occurs in a minority of patients with poorly differentiated carcinoma/adenocarcinoma of unknown primary site. Because most overexpressors had poorly differentiated adenocarcinoma, further evaluation of patients with adenocarcinoma of unknown primary site is necessary to determine the frequency of Her-2 overexpression in this common subgroup. Evaluation of the efficacy of trastuzumab in Her-2 overexpressors with carcinoma of unknown primary site is indicated.

Chemotherapy in carcinomas of unknown primary site: a high-dose intensity policy

BACKGROUND

Unknown primary tumors are highly malignant diseases which portend a dire prognosis. We designed a prospective high dose-intensity policy with the aim of improving the results obtained with conventional chemotherapy.

PATIENTS AND METHODS

Chemotherapy regimens were determined according to clinical features. In patients younger than 61 years with an ECOG performance status of 0 or 1, poorly differentiated adenocarcinoma or poorly differentiated carcinoma, and no evidence of brain or bone marrow involvement (group A), the treatment plan included four sequential high-dose courses with hematopoietic progenitor cell and growth factor support. Peripheral blood progenitor cells were collected by apheresis as the leukocyte counts recovered from the nadir induced by the first cycle of chemotherapy (doxorubicin 75 mg/m2, cyclophosphamide 6000 mg/m2). Patients then received two cycles of etoposide (800 mg/m2) and carboplatin (900 mg/m2) separated by one cycle of doxorubicin (75 mg/m2) and cyclophosphamide (3000 mg/m2). G-CSF (5 micrograms/kg/d) was given until engraftment. It was planned that cycles would be delivered every three weeks. The remaining patients (group B) received alternative cycles of AC (doxorubicin 50 mg/m2, cyclophosphamide 1000 mg/m2) and EP (etoposide 300 mg/m2, cisplatin 100 mg/m2). Cycles were given at two-week intervals with GM-CSF support (5 micrograms/kg/d) from day 4 to day 10. Patients without measurable lesions were included, since the major endpoint was survival.

RESULTS

Sixty patients entered the study. Twenty patients were assigned to group A and 40 patients to group B. In group A, 5 of 12 patients with measurable lesions (42%; 95% confidence interval (95% CI): 22%-62%) achieved major responses to chemotherapy, including one complete response. The duration of the overall median survival was 11 months. In group B, a major response was observed in 12 (39%; 95% CI: 28%-50%) of 31 patients with measurable lesions, including three complete responses. The overall median survival was 8 months. Hematological toxicities were noteworthy in both groups. Two toxic deaths occurred in group B.

CONCLUSION

Using these doses and schedules of chemotherapy, a high-dose intensity policy does not appear to improve the outcome of patients with carcinoma of unknown primary site. Alternative studies dealing with new drugs are required.

Unknown primary carcinoma: randomised studies are needed to identify optimal treatments and their benefits

This is a retrospective review of 101 patients with unknown primary carcinoma (UPC) treated between 1989 and 1994, on whom data were collected prospectively. 92 patients received platinum-based chemotherapy and 9 had single agent 5-fluorouracil (5-FU). In the platinum group, an objective response rate of 37.2% was seen, with a median duration of 4.5 months (range 1.9-17.5). There were no responses with 5-FU alone, while median survival was 6.4 months and was not different from the platinum group (P = 0.09). Considerable symptomatic resolution was noted, although the contribution of chemotherapy alone to this is difficult to define. The impact of tumour response on quality of life and survival in UPC requires further elucidation in prospective studies with a "best supportive care' arm. The superiority of platinum-based treatments reported in selected subgroups cannot be applied to the whole spectrum of UPC.

Metastases of unknown primary site

Despite the fact that effective therapy does not currently exist for the majority of patients presenting with metastases of unknown primary site, the last decade has witnessed significant advances in the approach to this heterogeneous disease. The use of modern pathologic techniques that frequently provide better diagnostic precision and the recognition of specific subgroups with a favorable prognosis and responsiveness to treatment has improved the outcome for some patients. Currently the diagnostic strategy should emphasize the rapid identification of patients likely to benefit from available therapy, whereas clinical research should focus on the development of more effective treatments for those patients with unresponsive tumors. In the future, continued improvements in the molecular characterization of these tumors will likely enhance understanding of the metastatic process, allow for more specific definitions of cell lineage, and provide insights for better therapy.

Adenocarcinoma of unknown primary: retrospective analysis of chemosensitivity of 313 freshly explanted tumors in a tumor cloning system

Cancer of unknown primary origin is the eighth most common form of malignancy and accounts for up to 10% of all neoplasms diagnosed. It is a set of heterogenous tumors with widely varying sensitivity to systemic chemotherapy. Over the past years progress has been made in identifying subsets of patients that can be effectively treated with chemotherapy and may achieve long-term survival even with metastatic disease. However, the large majority of cancers of unknown origin still is resistant to chemotherapy. In an attempt to identify conventional and investigational new agents with possible activity against cancers of unknown primary, we have retrospectively analyzed the results of chemosensitivity testing in a soft agar cloning system in vitro and have compared these data with published clinical trials. Between 1978 and 1993, a total of 19584 tumor specimens were studied using a variety of investigational or established antitumor agents. Of these, 615 (3.1%) were tumors of unknown origin and confirmed on pathology review. The largest histologic subgroup was adenocarcinoma (332, 54%). Sufficient numbers of cells for in vitro testing were obtained from 313 tumor specimens (94.3%). Of 278 agents tested in adenocarcinoma of unknown origin, borderline activity (< 20% in vitro response) was noted for 5-FU, doxorubicin, bleomycin, mitoxantrone, mitomycin-C, cisplatin, and etoposide. In vitro response rates of > or = 20% were observed for actinomycin-D, BCNU, melphalan, methotrexate, taxol, and vinblastine. In addition, several investigational agents including fludarabine, amira235, bisantrene, Dupont840, echinomycin, tiazofurin, LY104208 (vinzolidine), intoplicine, and topotecan had activity.(ABSTRACT TRUNCATED AT 250 WORDS)