Clinical Relevance of Early Disseminated Breast Cancer Cells Depends on Their Cytokeratin Expression Pattern

Background: The factors determining the clinical relevance of disseminated tumor cells (DTC) in breast cancer patients are largely unknown. Here we compared the specificity and clinical performance of two anti-cytokeratin(CK) antibodies frequently used for DTC detection, namely A45-B/B3 (A45) and AE1/AE3 (AE). Additionally we explored the CK gene expression patterns in primary breast tumors.Methods: Specificities of antibodies A45 and AE for selected CKs were assessed by 2-DE western blot analysis. Using these antibodies bone marrow aspirates from 391 breast cancer patients (M0, pT1-3, pN0-3) were screened for the presence of DTC. To obtain prognostic information, patients were followed up over a median of 83 months for time to relapse and 99 months for time to death. Two breast cancer patient datasets (Oslo (n=123), and van de Vijver et al. (NEJM 2002; n=295)) were analysed for CK primary tumor gene expression patterns and grouped by hormone receptor (HR) status of the primary tumors. T-tests and hierarchial clustering analyses were applied.Results: AE detected CK5, CK7, CK8, and CK19, whereas A45 recognized CK7 and CK18. In total, 24 of 391 patients (6.1%) were DTC-positive for A45, and 41 (10.5%) for AE. Although concordance between the two antibodies was 84.4%, overlap among positive cases was only 3.2%. DTC-positivity with AE and A45 was more frequent in patients of higher nodal status (p=0.019 and p=0.036, respectively). Nearly all patients with A45-positive DTC had hormone receptor-positive tumors (23/24), while detection of AE-positive DTC was more frequent among hormone receptor negative patients (p=0.006). Clear differences in primary tumor CK expression patterns between HR+ and HR- tumors were detected in both datasets. Compared to HR- tumors, CKs up-regulated in HR+ tumors were CK8 and 18, in addition CK19 in two datasets, whereas e.g. CK5, CK6, CK7, CK14, CK15, CK16, and CK17 were significantly down-regulated.Survival analyses of all patients revealed shorter distant disease-free survival (p=0.039) for patients with A45-positive DTC, whereas the prognostic relevance of AE-positive DTC was restricted to node positive patients.Conclusion: The clinical utility of immunocytochemical DTC detection depends on the anti-CK antibody used, which may reflect the complex CK composition of DTC. Tumor CK expression patterns and their correlation to antibody-sprecific DTC detection will further be explored by A45- and AE- staining of corresponding patient samples.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3021.

Prognostic impact of the time interval between primary surgery and start of first-line chemotherapy in patients with advanced ovarian cancer: Analysis of prospective randomized phase III trials

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Background: Primary surgery followed by platinum-taxane chemotherapy is the standard therapy of advanced ovarian cancer. It is not clear, whether the time interval between surgery and start of first line chemotherapy (time to chemo - TTC) has an impact on the clinical outcome. Methods: Individual patient data meta-analysis of three prospective randomized AGO-OVAR/GINECO trials (AGO OVAR 3, 5, and 7) conducted between 1995 and 2002 to investigate platinum-taxane based chemotherapy regimens in advanced ovarian cancer. Cox proportional hazard models were applied to evaluate the prognostic impact of different variables on survival; TTC was introduced as a continuous variable. Results: A total of 3,326 patients were analyzed. Chemotherapy was started within 8 weeks after surgery. Median progression-free survival (PFS) was 17.91 months (95% CI: 17.15–18.73 months) and median overall survival (OS) 37.83 months (95% CI: 36.57–38.90 months). The median TTC was 19 days (95% CI: 18–19 days, range 1–56 days). By multivariate analysis of the total cohort, there was no significant association between TTC and PFS (p = 0.131) or OS (p = 0.372). In the subgroup of patients with no residual tumor after debulking surgery (n = 1.101), a significant and independent correlation between early start of chemotherapy and improved overall survival was observed (p = 0.022). Conclusions: Our analysis represents the largest study investigating treatment delivery and outcome in ovarian cancer. The time interval between primary surgery and start of first line chemotherapy seems to have no general impact in all patients. However, it could be demonstrated for the first time that a delayed start of chemotherapy was independently associated with decreased overall survival in patients with complete surgical debulking. As previously shown for other biological factors in ovarian cancer, the presence of residual tumor after surgery seems to prevail over the prognostic impact of therapy initiation.

No significant financial relationships to disclose.