Stephan Braun and colleagues have reported in the New England Journal of Medicine, that the detection of disseminated tumor cells in bone marrow samples is a more reliable determinant of metastasis and patient survival.
The disease progression is measured by taking biopsy samples from breast cancer patients and the level of lymph node metastases is measured to determine the disease prognosis. But research results as shown that 30% of patients with lymph node negative status still develop metastatic disease. A new approach to overcome this has been found in which the detection of micrometases in bone marrow is detected which can be a better clinical tool for early detection of disease metastasis.
Breast tumor cells frequently bypass the lymph nodes and disseminate directly through the blood to distant organs. This Hematogenous dissemination of cancer cells has been shown to be an early event in tumor progression. Analysis of data from 9 studies involving 4,703 patients with stage I, II or III breast cancer, the authors evaluated the association between detection of bone marrow micrometastases and patient outcome over a 10 year period.
The study compared the effects of different factors, such as tumor size, grade, bone marrow metastasis, lymph node metastasis and hormone receptor expression , and revealed that the presence of micrometases in bone marrow were the best predictors of outcome within the first 5 years after diagnosis. Bone marrow micrometastases were detected in over 30% of patients and these patients were found to develop larger tumors with a higher histological grade that more frequently metastasized to other organs.
Patients with bone marrow micrometastases were more likely to die of the disease, even among patients that received adjuvant therapy. In patients with very small tumors without lymph node metastases, and who therefore did not receive adjuvant therapy, the presence of bone marrow micrometastases was also associated with shorter survival times. This procedure of detecting bone marrow micrometastases could be a complementary approach to lymph node biopsies in determining which patients should receive adjuvant therapy.
Source: Nature Review Cancer.