Preoperative detection of peripherally circulating cancer cells and its prognostic significance in ovarian cancer☆

Disseminated tumor cells in bone marrow may affect prognosis of patients with gynecologic malignancies

INTRODUCTION

The presence of disseminated tumor cells (DTC) in the bone marrow (BM) of breast cancer patients is associated with poor prognosis. Several studies demonstrated that tumor cell dissemination may occur in gynecologic cancer and affect clinical outcome. The aim of our study was to evaluate the incidence of DTC and to assess their prognostic significance in patients with gynecologic malignancies.

METHODS

Bone marrow aspirates from 377 patients with primary ovarian (112), endometrial (141), cervical (102), and vulvar cancer (22) undergoing surgery at the Department of Gynecology and Obstetrics, University Hospital, Tuebingen, Germany between November 2001 and November 2007, were included into the study. Disseminated tumor cells were identified by immunocytochemistry using the pancytokeratin antibody A45B/B3 and by cytomorphology.

RESULTS

Disseminated tumor cells were detected in 19% of BM aspirates from patients with gynecological malignancies. Incidences of DTC in ovarian, endometrial, cervical, and vulvar cancer were 25%, 16%, 19%, and 5%, respectively. For patients with ovarian and endometrial cancer, no correlation with established clinicopathological factors was observed. In case of cervical cancer, BM positivity was correlated with International Federation of Gynecology and Obstetrics stage, tumor size, and nodal involvement. Bone marrow positivity of ovarian cancer patients was correlated with significantly shorter disease-free survival (P = 0.035). For other tumor entities, no association between BM status and clinical outcome could be observed.

CONCLUSIONS

We conclude that up to 25% of patients with loco-regionally restricted gynecologic malignancies present with DTC at the time of diagnosis. For ovarian cancer patients, BM status affected clinical outcome.

Clinical significance of circulating tumor cells detected by an invasion assay in peripheral blood of patients with ovarian cancer

OBJECTIVES

The invasive growth of circulating tumor cells (CTCs) propagates cancer metastasis. The aims of this study were to evaluate the association of invasive CTCs, detected by a novel cell invasion assay, with disease stage, CA-125 level and patient survival.

METHODS

Peripheral blood samples from 71 patients undergoing evaluation for ovarian malignancy were assessed for the presence of invasive CTCs using a cell invasion assay that enriches and identifies tumor cells with a cell adhesion matrix (CAM). Invasive CTCs were identified as cells exhibiting CAM invasion (CAM+) and expressing standard epithelial markers (Epi+).

RESULTS

43 (60.6%) patients had detectable CTCs: 0/5 benign patients, 1/10 (10%) early stage, 39/52 (73.1%) late stage and 3/4 (75%) unstaged patients (p-value <0.001). CTC counts ranged from 0-149 CTCs/ml with stage III/IV patients exhibiting significantly higher mean counts (41.3 CTCs/ml) than stage I/II patients (6.0 CTCs/ml) and benign patients (0 CTCs/ml, p-value=0.001). A positive correlation between CTC count and CA-125 level was observed (Spearman correlation coefficient r=0.309, p-value=0.035). Kaplan-Meier curves revealed a significant decrease in disease-free survival in patients with detectable CTCs (median survival 15.0 months vs. 35.0 months, log-rank p-value=0.042). Tumor grade and tumor histology did not influence CTC detection.

CONCLUSIONS

Invasive CTCs can be detected in a majority of epithelial ovarian cancer patients and may predict shorter disease-free survival. Furthermore, higher CTC counts may reflect later stage disease and higher CA-125 levels.

Mechanisms of transcoelomic metastasis in ovarian cancer

Metastasis from epithelial ovarian cancer can occur via the transcoelomic, haematogeneous, or lymphatic route. Of these, transcoelomic metastasis is the most common, and is responsible for the greatest morbidity and mortality in women with this disease. Unfortunately, very little is known about the mechanisms behind this process. This review assesses the current evidence and ideas about the biology of transcoelomic dissemination. The mechanisms of cell detachment, migration, and implantation in transcoelomic metastasis are placed within the context of clinical observations of ovarian cancer to derive a stepwise hypothesis of this process. Evidence for transcoelomic dissemination versus transcoelomic metaplasia in ovarian cancer is presented. Future high throughput microarray studies that compare changes at a genomic and gene expression level between primary ovarian tumours and their peritoneal metastases are hoped to lead to a more conclusive picture of transcoelomic metastasis, and to delineate the key molecular players in this process. These studies might also result in the identification of potential new therapeutic targets in ovarian cancer.

The use of a panel of monoclonal antibodies to enrich circulating breast cancer cells facilitates their detection

OBJECTIVE

Metastatic relapse due to early dissemination of tumor cells is associated with poor prognosis for epithelial cancer. The molecular characterization of these single cells or cell clusters that have evaded the tumor is indispensable in order to evaluate their biological behavior and metastatic potential. In this study, we established a sensitive immunomagnetic method to isolate rare cancer cells from peripheral blood based on their expression of epithelial- or tumor-cell-specific markers.

METHODS

Low numbers of cells of breast cancer cell lines - ZR-75-1, MCF-7, HBL-100 - were spiked into peripheral blood specimens of healthy volunteers. Enrichment of tumor cells was performed using either pre-coupled HEA and/or ErbB2 microbeads or a mixture of three monoclonal antibodies against HEA, ErbB2 and EGFR.

RESULTS

The recovery rate of spiked tumor cells correlated with the expression of the corresponding antigens. ZR-75-1 cells high expressing all three genes could be isolated to 60-71%. MCF-7 cells, which hardly express EGFR, showed a significant better recovery by using two specific antibodies in combination (50-68%) than one pre-coupled bead alone (31-42%). HBL-100 cells little expressing HEA could not be isolated with HEA microbeads and only to 27% in combination with ErbB2 beads -in contrast the use of an antibody cocktail achieved 38%.

CONCLUSION

As tumor and epithelial specific cell marker antigens are expressed differently in disseminated tumor cells, the immunomagnetic enrichment from peripheral blood is most robust and reliable when using a combination of specific antibodies compared to single antibodies.