Background: The presence of disseminated tumor cells in the bone marrow (BM) of breast cancer patients is associated with poor prognosis and may therefore be related to aggressive breast cancer as indicated by tumor biological and clinicopathological factors. The aim of this study was to identify those features of the primary tumor related to the presence of disseminated tumor cells in the BM.
Patients and methods: Clinical data from 508 primary breast cancer patients were analyzed. Tumor biological features of the primary tumor including HER2, p53, Ki-67, bcl-2 and hormone receptor status, as well as clinicopathological factors including histology, menopausal status, lymph node status, tumor size and grade, were studied for their association with BM involvement by univariate and multivariate analysis.
Results: Two-hundred and two out of 508 (40%) primary breast cancer patients had disseminated tumor cells in the BM. p53 expression, hormone receptor status, HER2 and Ki-67 were significantly related to BM involvement. The multivariate analysis revealed that p53 expression (OR: 1.9, 95% CI: 1.2 - 3.0) followed by progesterone receptor status (OR: 1.5, 95% CI: 1.0 - 2.2) were the only independent determinants for BM involvement.
Conclusion: The presence of disseminated tumor cells in the BM was not influenced by tumor load as reflected by tumor size and lymph node involvement, whereas tumor biological factors were independently correlated to BM involvement. The results substantiate the important role of tumor biological factors of the primary tumor for tumor cell dissemination.