Researchers in Germany are reporting that a new bone marrow test for persons with breast cancer may help determine who is most at risk for a cancer recurrence after initial treatment and is therefore in need of additional preventive treatment measures.
Breast cancer is characterized by the presence of cancer cells in the tissue or ducts of the breast. Depending on the stage of disease, treatment options may include surgery, chemotherapy, radiation therapy, and/or hormone therapy. Treatment for persons with cancer that has spread to the lymph nodes under the arm (
advanced localized breast cancer) usually involves surgery to remove the cancer and surrounding tissue (
lumpectomy) or to remove the breast (
mastectomy). To kill any cancer cells that may remain and to prevent a recurrence of the cancer, radiation therapy and chemotherapy are usually administered after surgery. However, for persons with cancer that is small in size or that has not spread to the lymph nodes (
localized breast cancer), the likelihood of recurrence is thought to be lower, and chemotherapy is not routinely given after surgery. Currently, doctors rely on the size of the cancer, whether the cancer has spread to the lymph nodes, and a patient’s age to predict whether breast cancer is likely to recur some time after the initial treatment, but better predictors of recurrence are needed.
When breast cancer does spread, doctors believe that 1 of the first sites to be involved is the bone marrow. This is important because if doctors could test the bone marrow for the presence of cancer cells early, they may be able to predict which persons are most likely to have a recurrence and are therefore most in need of additional preventive treatments. Now, researchers in Germany have evaluated a relatively new test, which uses what is called an
cytokeratin, to detect the early spread of cancer cells to the bone marrow. Cytokeratin-positive cells are an indication of the presence of cancer cells.
German researchers evaluated women with stage I, II, and III breast cancer with the cytokeratin bone marrow test to determine who was at risk for cancer recurrence after initial treatment. Thirty-three percent of the 552 patients with localized breast cancer had cytokeratin-positive cells in their bone marrow. After 4 years, 50% of the patients who had cytokeratin-positive bone marrow tests had a recurrence of cancer, and 35% died. Those who did not have cytokeratin-positive cells had a recurrence rate of only 10%, and a survival rate of more than 90%. Of the 245 patients who had breast cancer that did not involve the lymph nodes and who did not have chemotherapy after surgery, 81 had cytokeratin-positive cells in the bone marrow. Twenty-two percent of this cytokeratin-positive group had a recurrence, while only 2% of those with cytokeratin-negative bone marrow cells had a recurrence. Patients who had both spread to the lymph nodes and cytokeratin-positive cells in the bone marrow had the poorest outcomes.
These findings clearly show that the cytokeratin bone marrow test can be useful in predicting which persons with localized breast cancer are at high and low risk for a recurrence of cancer after their initial therapy. It appears that it is important for persons who are not scheduled to have chemotherapy after their initial therapy to undergo the cytokeratin bone marrow test. Those who have neither spread of cancer to the lymph nodes nor cytokeratin-positive cells in the bone marrow can likely be spared additional treatment. Persons who have lymph node involvement and cytokeratin-positive cells in the bone marrow after the initial therapy should consider receiving a newer chemotherapy combination with paclitaxel or a high-dose chemotherapy regimen followed by a stem cell transplantation.
These researchers concluded that further studies are now needed to determine how the cytokeratin bone marrow test can best be used to help persons with localized breast cancer and their doctors make effective treatment decisions. Persons with breast cancer may wish to talk with their doctor about the risks and benefits of the cytokeratin bone marrow test, or of participating in a clinical trial in which new chemotherapies are being studied.
(New England Journal of Medicine, Vol 342, No 8, pp 525-533, 2000)