Implications of occult metastatic cells for systemic cancer treatment in patients with breast or gastrointestinal cancer.

The early and clinically occult spread of viable tumour cells to the organism is becoming acknowledged as a hallmark in cancer progression, since abundant clinical and experimental data suggest that these cells are precursors of subsequent distant relapse. Using monoclonal antibodies against epithelial cytokeratins or tumour-associated cell membrane glycoproteins, individual carcinoma cells can be detected in cytological bone marrow preparations at frequencies of 10(-5) to 10(-6). Prospective clinical studies have shown that the presence of such immunostained cells in bone marrow is prognostically relevant with regard to relapse-free and overall survival, even in malignancies that do not preferentially metastasise to bone. As current treatment strategies have resulted in a substantial improvement of cancer mortality rates, it is noteworthy to consider the intriguing options of immunocytochemical screening of bone marrow aspirates for occult metastatic cells. Besides improved tumour staging, such screening offers opportunities for guiding patient stratification for adjuvant therapy trials, monitoring response to adjuvant therapies (which, at present, can only be assessed retrospectively after an extended period of clinical follow-up), and specifically targeting tumour-biological therapies against disseminated tumour cells. The present review summarises the current data on the clinical significance of occult metastatic cancer cells in bone marrow.     

Clinical significance of proliferative potential of occult metastatic cells in bone marrow of patients with breast cancer

There is increasing statistical evidence that the presence of tumour cells in bone marrow detected by immunocytochemistry represents an important prognostic indicator in breast cancer, but their individual capacity to become clinical metastases is unknown. The aim of this study was to assess the proliferative capacity of these occult metastatic cells in the bone marrow of patients with various stages of breast cancer. We obtained bone marrow aspirates from 60 patients with breast cancer before treatment with chemotherapy: 17 stage II, 12 stage III and 31 stage IV. After bone marrow culture for 6-34 days (median: 17 days) under specific cell culture conditions, viable epithelial cells were detected by cytokeratin staining in 40 patients (66%). Expansion of tumour cells was poorly correlated with tumour cell detection on primary screening (P=0.06). There was a nonsignificant correlation between the number and the presence of expanded tumour cells and the UICC stage of the patients. On primary screening, tumour cell detection was positive in 56% of patients and was correlated with clinical UICC stage (P=0.01). However, with a median follow-up of 23 months, expansion of tumour cells from bone marrow was associated with decreased patient survival (P=0.04), whereas the survival difference according to detection of CK-positive cells on primary screening was not statistically significant. In conclusion, viable tumour cells can be detected in the bone marrow of breast cancer patients. Their proliferative potential could be predictive of outcome and deserves further investigation.     

Analysis of and prognostic information from disseminated tumour cells in bone marrow in primary breast cancer: a prospective observational study

ABSTRACT: BACKGROUND: Disseminated tumour cells (DTCs) in the bone marrow of patients with breast cancer have been identified as an independent predictor of poor prognosis in patients with non-metastatic disease. This prospective study aimed to evaluate the presence and prognostic value of DTCs in the bone marrow of female patients with primary breast cancer. METHODS: Between 1999 and 2003, bone marrow aspirates were obtained from patients at the time of surgery for primary invasive breast cancer. DTCs in bone marrow were identified using monoclonal antibodies against cytokeratins for detection of epithelial cells. The detection of DTCs was related to clinical follow-up with distant disease-free survival (DDFS) and breast cancer-specific survival as endpoints. Bone marrow aspirates from adult healthy bone marrow donors were analysed separately. RESULTS: DTCs were analysed in 401 patients, and cytokeratin-positive cells were found in 152 of these (38%). An immunofluorescence (IF) staining procedure was used in 327 patients, and immunocytochemistry (IC) was performed in 74 patients. The IF-based method resulted in 40% DTC-positive cases, whereas 30% were positive using IC (p = 0.11). The presence of DTCs in bone marrow was not significantly related to patient or tumour characteristics. The presence of DTCs was not a prognostic factor for DDFS (IF: hazards ratio [HR], 2.2; 95% confidence interval [CI], 0.63--2.2; p = 0.60; IC: HR, 0.84; 95% CI, 0.09--8.1; p = 0.88). Significant prognostic factors were lymph node metastases, oestrogen receptor positivity, Nottingham histological grade, and tumour size using Cox univariate analysis. The analyses were positive for epithelial cells in bone marrow from adult healthy donors in 19 (25%) samples. CONCLUSIONS: The detection of DTCs in bone marrow in primary breast cancer was previously shown to be a predictor of poor prognosis. We were not able to confirm these results in a prospective cohort including unselected patients before the standard procedure was established. Future studies with a standardised patient protocol and improved technique for isolating and detecting DTCs may reveal the clinical applications of DTC detection in patients with micrometastases in the bone marrow.     

Removal of tumour cells from bone marrow: an evaluation of the available techniques

Autologous bone marrow transplantation has offered a way of increasing the dose of drugs and radiotherapy which can be used to treat patients with malignant disease in an attempt to eradicate tumour. Bone marrow is taken prior to treatment and returned to the patient to 'rescue' haemopoietic function after ablative therapy is completed. Bone marrow removed for autograft may be contaminated with tumour cells at the time of harvest, and it is undesirable to return these to patients even though there are little data available concerning the number of tumour cells necessary to reseed various malignancies. This review considers the various methods available for removing tumour cells from bone marrow destined for autologous transplantation, and evaluates their advantages and disadvantages.     

Occult micrometastasis: enrichment, identification and characterization of single disseminated tumour cells

The decision as to whether systemic adjuvant therapy should be applied in breast cancer patients for secondary prevention of metastatic relapse is based solely on the statistical prognosis. For this reason, the direct identification of minimal residual cancer in distant organs (e.g. bone marrow) is of particular importance. In breast cancer 25-43% of the patients exhibit micrometastatic disease in bone marrow, following resection of their primary tumours. Successful enrichment, reliable identification and molecular profiling of disseminated tumour cells at the single cell level are still key issues in ongoing and future studies. In addition, first attempts have been reported to evaluate the biology of disseminated tumour cells using in vitro and in vivo models. Taken together, the advancing characterization of disseminated tumour cells opens the avenue for the development of new therapeutic approaches aimed at preventing metastatic relapse.     

Bone marrow and lymph node assessment for minimal residual disease in patients with breast cancer

The immunocytological detection of disseminated epithelial cells in bone marrow in patients with breast cancer has been performed at many hospitals and institutes since the early 1980s. Despite numerous publications in this field, it has not been possible to standardize the method and establish the 'ideal' antibody, either nationally or internationally. Molecular biological methods using PCR technology could extend the diagnostic spectrum. However, one of the major problems in breast cancer is the lack of a disease-specific marker gene. As a result, immunocytology is still the standard procedure for tumour cell detection.The detection of disseminated single cells in bone marrow in primary breast cancer (also known as minimal residual disease) is a new prognostic factor for disease-free and overall survival. This has been demonstrated in two large (N > 300) groups and several small to medium groups (N = 50-300). As a marker of dissemination in a target organ for metastasis this prognostic factor corresponds much more closely to the tendency of breast cancer to early haematogenic spread. Tumour cell detection may predict the course of the disease better than the axillary lymph node status. Bone marrow aspiration and detection of disseminated cells might replace lymph node dissection, at least in those patients with small tumours and no clinical signs of lymph node involvement. This strategy will soon be investigated in appropriate studies. Another possible clinical use might be in deciding on whether or not to give adjuvant systemic therapy to node-negative patients. Patients with positive tumour cell detection are at a higher risk of subsequent metastasis, even if the axillary nodes are histologically normal.The immunohistological or molecular biological detection of tumour cells in axillary lymph nodes might also be very useful, now that it has been shown that a considerable subset of patients determined to be node-negative by means of conventional methods, are positive according to these new techniques. These methods could be a useful supplement to sentinel node biopsy. A further potential use of this method is in monitoring therapy with new treatment modalities such as gene therapy and immunotherapy. Repeated bone marrow aspiration can provide information on the success of therapy in minimal residual disease (cytoreduction). Immunocytochemical investigation of individual cells may be useful in studying the pathogenesis of metastasis, in particular in the skeleton. Phenotyping of cells might allow statements to be made on the metastatic potential of cells and the question of cell dormancy. It remains to be hoped that this aspect of minimal residual disease will be granted more attention in future.     

The direct molecular analysis of metastatic precursor cells in breast cancer: A chance for a better understanding of metastasis and for personalised medicine

The search for disseminated cancer cells has become a routine procedure in many clinical centres since the pioneering work of Riethmüller and Schlimok was published in the mid 1980s. Until today, clinical studies have mostly focused on the prognostic role of disseminated cancer cells that can be detected in bone marrow samples before manifestation of metastasis. As a more recent development, the field is increasingly concentrating on the prognostic information provided by tumour cells circulating in the peripheral blood instead of analysing the nature of disseminated tumour cells that have successfully homed to a new microenvironment and may eventually grow into metastases. This review critically questions that direction and proposes exploiting the unique opportunities provided by the direct molecular analysis of metastatic precursor cells for a better understanding of metastasis, tumour dormancy, therapy target identification, and personalised medicine in an adjuvant therapy setting.     

Molecular biology of breast metastasis: Clinical implications of experimental studies on metastatic inefficiency

Recent technological advances have led to an increasing ability to detect isolated tumour cells and groups of tumour cells in patients' blood, lymph nodes or bone marrow. However, the clinical significance of these cells is unclear. Should they be considered as evidence of metastasis, necessitating aggressive treatment, or are they in some cases unrelated to clinical outcome? Quantitative experimental studies on the basic biology of metastatic inefficiency are providing clues that may help in understanding the significance of these cells. This understanding will be of use in guiding clinical studies to assess the significance of isolated tumour cells and micrometastases in cancer patients.     

Molecular biology of breast cancer metastasis. Clinical implications of experimental studies on metastatic inefficiency

Recent technological advances have led to an increasing ability to detect isolated tumour cells and groups of tumour cells in patients' blood, lymph nodes or bone marrow. However, the clinical significance of these cells is unclear. Should they be considered as evidence of metastasis, necessitating aggressive treatment, or are they in some cases unrelated to clinical outcome? Quantitative experimental studies on the basic biology of metastatic inefficiency are providing clues that may help in understanding the significance of these cells. This understanding will be of use in guiding clinical studies to assess the significance of isolated tumour cells and micrometastases in cancer patients.     

Extraneural metastatic medulloblastoma in an adult

Summary Medulloblastoma is a rare malignancy in adults, accounting for approximately 1% of all primary brain tumors. Extraneural metastases have been reported in 10–30% of cases and most commonly involve bone; rarely lymph nodes, visceral organs and bone marrow may be involved with disease. We report here our experience with a 26 year-old woman with medulloblastoma treated with gross total resection followed by radiation therapy to her craniospinal axis. She subsequently developed widespread metastatic disease involving bone exclusive of the calvarium and spine for which multi-agent salvage chemotherapy was utilized with initial good clinical response. She␣later relapsed within the lymph nodes and soft tissues of the pelvis and eventually suffered a local recurrence within the posterior fossa. The treatment of medulloblastoma, particularly salvage therapy following disease recurrence, is reviewed.     

The management of non-seminomatous germ-cell tumours patients with viable malignancy at the time of RPLND

What should I do if my first-line chemotherapy has not irradicatedall active germ-cell tumour (GCT)? This is the clinical conundrumaddressed by Fizazi et al. [1] in this issue of Annals of Oncology,an area of controversy but not a lot of light. Standard therapy for patients with metastatic non-seminomatousgerm-cell tumours remains the use of combination cisplatin-basedchemotherapy with the current standard of care being three orfour cycles of bleomycin, etoposide and cisplatin (BEP) chemotherapydepending on the prognostic category [2–4]. The majorityof patients are cured by such therapy with long-term survivalexpected in >90% [3–5] except for the minority withpoor prognosis disease. Approximately, a third of these patients,however, will be left with residual masses over 1–2 cmfor which surgery is advised     

Clinical relevance of circulating tumour cells in the bone marrow of patients with SCCHN

BACKGROUND: Clinical outcome of patients with head and neck squamous cell carcinoma (SCCHN) depends on several risk factors like the presence of locoregional lymph node or distant metastases, stage, localisation and histologic differentiation of the tumour. Circulating tumour cells in the bone marrow indicate a poor prognosis for patients with various kinds of malignoma. The present study examines the clinical relevance of occult tumour cells in patients suffering from SCCHN. PATIENTS AND METHODS: Bone marrow aspirates of 176 patients suffering from SCCHN were obtained prior to surgery and stained for the presence of disseminated tumour cells. Antibodies for cytokeratin 19 were used for immunohistochemical detection with APAAP on cytospin slides. Within a clinical follow-up protocol over a period of 60 months, the prognostic relevance of several clinicopathological parameters and occult tumour cells was evaluated. RESULTS: Single CK19-expressing tumour cells could be detected in the bone marrow of 30.7% of the patients. There is a significant correlation between occult tumour cells in the bone marrow and relapse. Uni- and multivariate analysis of all clinical data showed the metastases in the locoregional lymph system and detection of disseminated tumour cells in the bone marrow to be statistically highly significant for clinical prognosis. Conclusion: The detection of minimal residual disease underlines the understanding of SCCHN as a systemic disease. Further examination of such cells will lead to a better understanding of the tumour biology, as well as to improvement of diagnostic and therapeutic strategies.     

Clinical relevance of occult metastatic cells in the bone marrow of patients with different stages of breast cancer

Data are emerging about the prognostic relevance of occult metastatic cells in the bone marrow of patients with various solid tumors. Discrepancies among different studies on the prognostic relevance of isolated tumor cells may be caused by tumor cell heterogeneity and the use of different immunoassays. There is increasing evidence that validated anticytokeratin antibodies (e.g., A45-B/B3) represent the present standard for the detection of isolated tumor cells. This immunocytochemical assay allows the identification of patients with occult tumor cell dissemination that cannot be identified by conventional screening methods in tumor staging. According to recent studies, these patients are at higher risk for subsequent development of distant metastases and might therefore benefit from early systemic therapy. At advanced stages of the disease, the micrometastatic tumor load after adjuvant therapy, or at the time of emerging recurrences, appears to reflect the tumor's ability to progress. Therapeutic monitoring and cell-cycle independent antibody-based therapy are among possible implications of this new, promising diagnostic tool. The present review also focuses on state of the art, reliable detection methods of occult metastatic cells in the bone marrow of breast cancer patients and on the prognostic relevance of these cells at different stages of the disease.     

The radiocolloid bone marrow scan in malignant disease

The radiocolloid bone marrow scans in 107 patients with malignant disease were reviewed. The observed scan patterns were classified into five groups: normal (type 1), moderately expanded (type 2), greatly expanded (type 3), peripheral expansion with central depression (type 4), and greatly reduced to absent intramedullary marrow (type 5). Correlation was made between scan pattern and clinical status of the patient for each disease category. In polycythemia vera, there was progressive expansion of the marrow organ that correlated well with the patient's course but not duration of disease. Type 3 or 4 marrow scans were associated with failure of effective marrow function. In myelofibrosis, regardless of associated cause, the scan pattern was predominantly type 4 or 5. Among the 42 patients with leukemia, 41 had abnormal scans. Type 4 was the characteristic scan pattern in untreated acute leukemia, and the scan became more normal with favorable treatment response. Patients with chronic myelogenous leukemia, either with myelofibrosis or blast crisis, had a type 4 or 5 marrow pattern. Scan patterns in the 30 patients with Hodgkin's disease were influenced by stage of disease and prior therapy. In untreated patients of stage I-II, the scan pattern was always normal. Among the 17 stage III or IV patients, scan patterns of type 4 or 5 were frequently observed regardless of previous therapy. Focal defects were common in this group and were of two types: (1) a small irregular defect due to infiltration of tumor (two cases), and (2) a sharply circumscribed defect due to radiation therapy (seven cases). Patients with metastatic malignancy and lymphosarcoma involving bone marrow had abnormal scans showing peripheral expansion or focal defects. Some of the clinical applications for radiocolloid marrow scanning that were suggested for these observations include determining optimal bone marrow biopsy site, aiding staging and the evaluation of treatment response for hematologic malignancies, screening patients for metastatic involvement of bone as an adjunct to the strontium-85 bone scan, and evaluating extent of bone marrow injury following radiation therapy. It is concluded that the radiocolloid scan of the bone marrow organ can be an important aid in management of patients with malignant disease.     

Immunodetection of bone marrow micrometastases in breast carcinoma patients and its correlation with primary tumour prognostic features.

Methods such as immunohistochemistry that have enhanced the detection of carcinoma cells in bone marrow aspirates appear to be useful in identifying patients with aggressive tumours. To detect epithelial cells in bone marrow aspirates from breast carcinoma patients, we used a pool of five different monoclonal antibodies (MAbs), which recognise 100% of breast carcinomas, together with the alkaline phosphatase method on cytospun cells obtained from sternum and iliac crest. Primary tumours were also analysed for the expression of the c-erbB-1 and c-erbB-2 oncogene products, and of two differentiation-related markers and laminin receptors. Immunoreactive cells were detected in the bone marrow of 62 of the 197 patients tested (31%) without any correlation with clinical parameters such as tumour size or lymph node metastasis, whereas a significant (P < 0.01) correlation was found with enhanced monomeric laminin receptor expression in the primary tumour. In fact, this receptor was expressed in respectively 63% and 38% of primary tumours from patients with and without immunoreactive cells in the bone marrow aspirates. Thus, the presence of immunoreactive cells in bone marrow correlates with the expression in the primary tumour of a marker of the metastatic potential of the tumour, the 67 kDa laminin receptor.     

Update of results of autologous bone marrow transplantation in lymphoma

A substantial proportion of patients with Hodgkin’s disease and non-Hodgkin’s lymphoma will fail to achieve a complete remission with initial chemotherapy or will relapse after attaining a complete remission. The results of conventional salvage chemotherapy regimens for these patients have been disappointing. This has led to the use of highdose therapy regimens which can be administered with the use of hematopoietic rescue (bone marrow transplantation). The use of bone marrow transplantation for patients with relapsed and refractory lymphoma has increased rapidly. Data from the North American Autologous Bone Marrow Transplant Registry indicate that approximately 40 % of autologous bone marrow transplants are being performed for patients with lymphoma. Several large series of transplantation for Hodgkin’s disease and non-Hodgkin’s lymphoma have been published in the last two years^1-12. The results of these series vary widely due to differences in patient selection and pre-transplant prognostic factors. Differences in supportive care and preparative regimens prior to transplant may also account for the wide range of outcomes reported after transplantation. Although these differences make it impossible to compare results of one series with another, it is clear that a significant proportion of patients can achieve long term disease free survival following high dose therapy with marrow transplantation. It is also important, however, to note that this form of therapy can be associated with substantial morbidity and mortality. Transplant-related mortality exceeds 20 % in some series. However, greater experience, better patient selection, and advances in supportive care, such as hematopoietic growth factors, are allowing many institutions to perform transplantation with mortality rates under 5 %.     

18F-FDG whole body positron emission tomography (PET) in patients with unknown primary tumours (UPT)

The management of patients with unknown primary tumours (UPT) often includes a large number of radiographical studies and invasive procedures, but the occult primary tumour is detected in less than 25%. In this prospective study we explored whether non-invasive whole body PET scans using FDG (18-F-fluorodeoxyglucose) are of clinical value in detection of UPT. Whole-body FDG-PET scans were performed in 20 patients following standard staging procedures according to histology. PET results were verified either histologically or by the clinical course of the disease. 11 patients had neck metastases (5 squamous cell, 5 adenocarcinomas and 1 poorly differentiated carcinoma). The remaining patients had metastases located in bone (3), bone marrow (1), brain (1), pericardium (1), skin (1), pleura (1) and chest wall (1). All metastatic lesions were visible with PET. In 13 patients PET suggested the site for the primary tumour and this was verified in 9 (45%), either histologically or by the clinical course of disease. 8 of these had primary lung cancer and 1 had carcinoma at the basis of the tongue. In most patients PET had no treatment related implications. 3 patients with non-small cell lung cancer (NSCLC) received chemotherapy prompted by the PET result. The rest received either radical radiotherapy to the head and neck region (7), palliative radiotherapy to the metastatic lesion (8), chemotherapy based on signet ring cell carcinoma in bone marrow (1) or no therapy (1). These results indicates that PET is useful in UPT preceding expensive and invasive diagnostic procedures and can result in a faster diagnosis in approximately one third of the patients who then avoid unnecessary extensive procedures. Furthermore, a larger proportion of patients will receive treatment aimed at the correct diagnosis. A prospective cost-effectiveness analysis of PET in this setting is warranted     

Recent progress in multiple myeloma

Multiple myeloma is recognized as a neoplasm of phenotypically mature plasma cells which produces a variety of clinical symptoms related both to tumour infiltration of the bone marrow and cytokine production. The latter results in bone disease and a complex interactive network between plasma cells, marrow stromal cells and other hematopoietic cells. This serves to sustain the myeloma proliferative pool and promote maturation and secretion of monoclonal immunoglobulin. Whereas the recognizable tumour cells in myeloma are the most mature B cells, early lymphoid cells are involved in the disease and probably represent the proliferative pre-plasma cell compartment. The definition of the myeloma‘stem cell’ remains controversial, but our understanding of early pre-plasma cell differentiation in multiple myeloma has been aided by studies on normal non-neoplastic equivalents. Techniques like high resolution flow cytometry, flow cytometric DNA analysis and improvements in our ability to obtain karyotypic data in multiple myeloma will improve our understanding of myeloma cell biology, hopefully yielding new prognostic information. Finally, improvements in assessing prognosis will help identify patients whose survival with standard therapy is limited and how may require innovative or aggressive treatment protocols. These individuals must be separated from patients who either require no initial therapy or who are likely to have good outcomes with standard approaches.