There are different reasons why the detection of disseminated tumor cells (DTCs) in the hematopoetic system is important. On the one hand the detection of disseminated tumor cells can provide vital information about a tumor's tendency to develop metastases. In some localized epithelial but also in embryonic tumors, for example a correlation between disseminated tumor cells and unfavorable outcome was observed (6, 14). These studies are based on the assumption that those tumor cells which appear in the hematopoetic system at a very early stage are responsible for the development of metastases. Another important aspect is the monitoring of the disease response to cytotoxic drugs by quantifying DTCs. During and after therapy there is no other possibility (except for an operation) to either directly analyze the effects the therapy has on the tumor cells or to determine their biological characteristics. The dissemination in the hematopoetic system, however, reveals the response to therapy and the biological features of the tumor cells. The prerequisites for such bone-marrow diagnosis, however, is the unequivocal identification of disseminated tumor cells. So in order to avoid false positive results (which are a risk in bone-marrow diagnostics), a system was developed to distinguish tumor cells from non-neoplastic cells and to facilitate insights into the biological make-up of tumor cells (2, 11).
Early and clinically non-apparent hematogenous dissemination of tumor cells is considered an important prognostic factor and marker of tumor progression. This phenomenon is reported for tumor entities differing as much as breast and gastrointestinal cancers. First prospective studies point to the unique opportunity of therapy monitoring utilizing follow-up bone marrow aspirations before and after adjuvant therapy. First results of these studies further indicate that currently used treatment strategies such as chemotherapy may not be efficient enough to eliminate all metastatic cells in all of the cases studied. Apart from improved tumor staging, such screening efforts may not only help to improve planning and monitoring of adjuvant therapy (which at present is only possible retrospectively) but also help to design individualized targeted biological treatment. This review summarizes the currently available data on the importance of disseminated tumor cells for the treatment of patients with breast or gastrointestinal cancer.
Cancer mortality has only marginally decreased in the last decades despite huge diagnostic and therapeutic efforts. Early dissemination of cancer cells has to be blamed for this finding, because ectopically residing cells are necessarily left behind by the surgeon. Consequently, this cell population has been designated as minimal residual disease that may eventually lead to systemic relapse months or years after presumed curative surgery. Paradoxically, systemic adjuvant treatments are currently administered without any precise knowledge about the target population of such drugs. Here it is argued that the direct analysis of disseminated cells may be a prerequiste for the development of future therapies since first molecular genetic data of single disseminated cancer cells suggest an excessive intercellular heterogeneity and distant relationship to the primary tumor.
The clinical course of cervical carcinoma is widely determined by locoregional recurrence. There is increasing data, however, that haematogenic micrometastases occur early during the disease and might result in distant recurrence during follow-up. These occult disseminated tumor cells in blood, lymph nodes and bone marrow escape conventional tumor staging. Therefore, molecular and immunoytochemical techniques based on markers against human papilloma virus or cytokeratins (CK) have been applied. At present, there is only one study available on the prognostic relevance of disseminated tumor cells in bone marrow. No correlation between the bone marrow status and overall survival was observed. Still, there was a strong trend towards shorter distant disease free survival in patients with a positive bone marrow status. In view of the data on disseminated tumor cells in other tumor entities, these early results might offer new options for refined tumor staging and improved treatment options.
Early and clinically occult hematogenous dissemination of tumour cells is considered a sign of systemic tumour progression, since recent data suggest that these cells are seminal precursors of subsequent distant metastasis. Single isolated tumour cells can be detected by means of immunocytochemical and molecular techniques at frequencies as low as 10(-5) to 10(-6) exploring different body compartments, such as bone marrow, peripheral blood and lymph nodes. This review summarises the currently available data on techniques that can be used to detect metastatic breast cancer cells in bone marrow and values their opportunities and limitations.
The occurrence of occult metastases of solid tumors at initial diagnosis or during follow-up is of crucial therapeutical importance. The sensitive detection of such cells in hematological samples depends on tissue specific cellular markers. The demonstration of minimally disseminated tumor cells at a given timepoint is, however, only a snapshot, which does not give any information about the potential and dynamics of the cells in question. Functional differences may fundamentally influence the impact of a positive finding. The analysis of cell proliferation and cell death (apoptosis) in disseminated tumor cells, for instance, defines, whether the dissemination process is progressive or regressive. With a newly developed automatic image analysis station the investigation of functional parameters in isolated cells from clinical samples became possible. The studies presented here demonstrate, that such techniques allow an improved identification of isolated tumor cells with clinical importance.
Cytoreductive therapy can ameliorate symptoms in chronic myeloid leukemia (CML) but only treatment beyond hematologic remission aiming to affect the leukemic clone can improve prognosis. Up to now bone marrow transplantation is the only established therapy with the potential to completely eliminate the BCR-ABL positive cell population. Interferon-alpha (IFN-alpha) as well as cytosine arabinoside (ARA-C), particularly in combination, have been shown to be effective in achieving cytogenetic remission in some patients. With Glivec (STI-571) there is now a drug available which can induce major cytogenetic response in more than half of the patients who have failed IFN-alpha treatment and thus possibly delay or prevent blast crisis. Recent reports, however, have shown that primitive, quiescent, Philadelphia-positive stem cells are insensitive to STI-571 in vitro. Such cells could be the basis of relapse after termination of Glivec-therapy.
The detection of disseminated tumor cells in bone marrow and blood is increasingly used for staging and therapeutic decisions in breast cancer and other solid tumors. Molecular biological methods improve the diagnostic accuracy. Limitations of the approach relate to the lack of disease-specific marker genes. The detection of tumor cells in the bone marrow after primary therapy is a negative prognostic parameter in many solid tumours. Axillary lymph node dissection and histopathology remain the standard staging procedure in breast cancer, but nodal negative patients exhibiting tumor cells in the bone marrow have an inferior outcome and may benefit from adjuvant therapy. The immunohistochemical and molecular detection of tumour cells in lymph nodes reduces the number of truly nodal-negative patients considerably. Tumour cells in bone marrow and blood may be used to directly monitor therapeutic responses.
Immunocytochemical and molecular biological methods to analyze minimal residual disease (MRD) in colorectal cancer in blood and bone marrow were compared. The concept of a study in the Donauspital will be presented which will permit a comparative judgement of minimal residual disease in blood and bone marrow in patients with colorectal cancer.
To investigate the prognostic value of tumour cells in peripheral blood (pB) of breast cancer (BC) patients, pB samples from 143 patients with benign lesions of the breast and from 467 BC patients were tested via a nested RT-PCR assay for mammaglobin mRNA. No sample from patients with benign lesions of the breast was found to be mammaglobin positive in contrast to 5/310 (2%) BC patients with no evidence of disease (NED) and 46/157 (29%) patients with metastatic disease (MD). Two hundred and eighteen BC patients with NED were followed for at least 12 months. All five mammaglobin-positive BC patients relapsed 1-13 months after first examination of positive pB samples in contrast to 27/213 (13%) patients without detectable tumour cells in pB. Fifty-nine BC patients with MD were tested for mammaglobin expression in pB at the time of first diagnosis of MD; 20 of them (34%) were mammaglobin positive. Patients were followed for a median of 19 months (2-51 months). During this time, 19/59 (32%) died due to tumour progression. In Kaplan-Meier survival analysis, BC patients with mammaglobin-negative pB samples at time of diagnosis of MD lived significantly longer than mammaglobin-positive patients (log-rank test: P = 0.0013). In addition, mammaglobin was an independent prognostic parameter and the difference reached significance in univariate as well as in multivariate analysis (P < 0.01). We conclude that the presence of tumour cells in pB of BC patients is of prognostic value.
The cure of a tumor patient with gastrointestinal cancer is dependent on the extension of the primary tumor (TNM-classification) and the option of curative resection (R0-resection) at the time of operation. The additional application of multimodal therapy approaches has lead to an improvement of prognosis in different advanced tumor stages. Nevertheless, despite curative tumor resection about 50% of patients with locally advanced gastrointestinal cancer develop recurrent tumor disease or distant metastases and die tumor-related. A possible explanation is the seed of disseminated tumor cells in blood, bone marrow or lymph nodes pre-, intra- or postoperatively, but also during diagnostic procedures. Several studies have shown in the last years that the presence of minimal residual disease (MRD) influences the course of disease and the patient's prognosis after curative tumor resection. Although several groups have reported the prognostic impact of disseminated tumor cells in the different compartments of bone marrow, lymph nodes and blood, the phenomenon of minimal residual disease is not acknowledged as an established prognostic factor and is not integrated into the classification of the UICC. Therefore, no therapeutic consequences were drawn at present from the detection of disseminated tumor cells in patients with gastrointestinal cancer. A possible explanation are missing multi-center-studies, which confirm the results of the several single-center-studies. Standardization of study designs and methodical procedures and the evidence of reproduction are mandatory in order to value and interpret the multitude of studies and the available data in this field. Only these results will allow to decide if the presence and detection of disseminated tumor cells can alter the tumor staging and individualize or possibly minimize further oncological therapy strategies.
The immunocytochemical detection of isolated disseminated tumor cells (ITC) in the bone marrow of breast cancer patients, what is called minimal residual disease (MRD), has been demonstrated to be of prognostic value in all stages of the disease. In order to definitely prove the origin of these cells from the primary tumor it is necessary to identify common factors on both tumor tissue and ITC, furthermore a more detailed characterization could help to improve their prognostic impact by defining certain subgroups and possibly establish new therapeutic strategies. We examined the expression/amplification of HER2neu, CD 44 adhesion molecule and CD 31 angiogenetic factor on more than 200 primary tumor tissues by immunohistochemistry or fluorescence in situ hybridisation, resp., and found no sign. correlation with the detection of ITC. After a median follow-up of 32 months only ITC in the bone marrow were of prognostic significance. In a small number of patients we examined the expression of topoisomerase II alpha, a key enzyme of DNA replication, and its predictive value of eliminating ITC by anthracyclin based chemotherapy. No correlation with the presence of ITC before or after chemotherapy could be found, yet pat. with topoisomerase II alpha neg. tumors showed a trend to reduced disease free survival. Because of the very low number of ITC per bone marrow sample, the direct characterization of these factors on ITC stays difficult without the possibility of tumor cell enrichment or cell culture. Preliminary results on multi colour stained samples indicate that a selection of certain biological factors takes place during tumor cell dissemination.
Four risk-categories for diabetes probability where defined by measured random-blood glucose values: minimum risk (random blood glucose < or = 95 mg/dl), low (96-139 mg/dl), moderate (140-199 mg/dl), and high (> or = 200 mg/dl). Using these risk categories and other risk factors as age, sex, BMI, and cholesterol, further data analysis were made. Among high-risk patients, male sex was represented two fold compared to female sex. In +65 year old subjects the diabetes risk increased from 8.2% for the whole study cohort up to 12.1%. An increase of body weight was paralleled by an increased risk for diabetes, whereas in the highest diabetes risk-group, obese subjects (BMI subgroup 4) were twice as frequent as in the next lower risk category. Additionally, 62% of subjects with a high diabetes risk had elevated cholesterol levels.
The mean value of serum total cholesterol was 208 +/- 42 mg/dl for the study population. Sixty-five percent of investigated subjects had elevated cholesterol levels > 200 mg/dl. The percentage of subjects with low to moderate elevated cholesterol levels between 200-250 mg/dl was 40%, and 2% had a cholesterol higher than 300 mg/dl. Grouping the cholesterol levels by age and sex resulted in a high percentage of subjects with serum cholesterol > 200 mg/dl for the cardiovascular high-risk age group of 45-65 years old men and 55-75 years old women. Remarkably high was this percentage for women in this age-group; 71% had a cholesterol level > 200 mg/dl. In 59% of investigated women and 52% of men cholesterol should be lowered.
In Austria in 1999, a Diabetes screening program was carried out by the Austrian Diabetes Association and by Novo Nordisk and Roche Diagnostics with a special equipped bus touring through more than 90 cities. The population was invited to a screening of blood glucose (random), blood pressure, body weight und serum-cholesterol. The diabetes risk was evaluated by history and familiar burden with a questionnaire. The results were handed over to the visitors and their general practitioners, and a copy was used for anonymously analysis.
To improve efficiently the outcome of population based screening for diabetes, a preceding questionnaire could be useful to reduce the number of subjects for the chemical diabetes test. During the Austrian Diabetes-Bus-Tour, a questionnaire, proved in the U.S., was completed in 16,537 subjects without known diabetes. Further, the questionnaires were analysed by two different aspects: following the original American system and secondly, a system pronouncing the hereditary component of type 2 diabetes. In comparison of the measured blood glucose values und the questionnaire, in 28% of investigated subjects, at least 50% of expected newly diagnosed type 2 could be identified by the original American system. The point system with hereditary emphasis was not equally useful.
In comparison to non-diabetic normotensive control subjects, hypertensive diabetic patients have a four-fold increased risk for cardiovascular morbidity and mortality. Additional to WHO/IHS definition, the terminus "high-normal blood pressure" (systolic 130-140 mm Hg and diastolic 85 - < 90 mm Hg) was used for data analysis. The mean blood pressure was elevated among diabetic subjects (157/85 mmHg) when compared to the non-diabetic group (141/82 mm Hg). The analysis of visitors with an already known diabetes yielded only 14% of probands having normal blood pressure, whereby 63% of diabetic subjects were definitely in the hypertensive range. In overweight (BMI > 28 kg/m2) subjects, whose percentage in our population were 32%, blood pressure was elevated (RR > 150/90) in 51%. In subclasses with high blood pressure, an increased cholesterol level was often seen; 64% of these subjects had a cholesterol level of greater 200 mg/dl.
In 19,219 individuals (45.4% male, 54.6% female) with an age range from 10 to 95 years average body weight, body mass index (BMI), serum cholesterol and arterial blood pressure showed typical age-dependent changes. In the middle-aged between 45 and 65 years the high percentage of total cholesterol levels over 200 mg/dl (male: 58.3%; female 70.7%) seems alarming. In very old persons over 80 years the predictive value of those cardiovascular risk factors for increased mortality might be reversed, since in several epidemiological observations higher total cholesterol values and a high systolic blood pressure were associated with a longer survival. Average random blood glucose concentration is steadily rising with age. In good comparison with results from US American and European studies the age-matched relative risk for known myocardial infarction and stroke is twice to four times higher in individuals with known diabetes mellitus than in those without. These findings underline the urgent need for broadly based screening programs looking for metabolic and cardiovascular risk factors and for early disturbances of carbohydrate metabolism particularly in middle-aged groups, and for manifest diabetes mellitus in persons over 65 years of age.
