According to a recent article published in The New England Journal of Medicine, genetic microarray analysis may help predict outcomes and thus individualize treatment for patients with stages I-II breast cancer.
Stages I-II breast cancer refers to cancer that is localized and may involve the axillary (under the arm) lymph nodes. Standard therapy for early-stage breast cancer includes the surgical removal of the cancer, radiation therapy, chemotherapy and/or hormonal therapy. Although overall cure rates for patients with stages I or II breast cancer are favorable, a significant fraction of patients will develop spread of their disease and ultimately succumb to breast cancer. Researchers have been evaluating different variables or factors that may put a patient at a high risk for developing a recurrence of their disease. Factors currently used in practice to determine if a patient with early-stage breast cancer is at a high risk of not being cured following therapy include the age of a patient, the size of the cancer, the number of lymph nodes involved and aggressiveness of the cancer as determined through laboratory processes. However, these risk factors are less than precise in accurately predicting failure of therapy.
Genetics is emerging as a potential tool to determine individual characteristics of patients and their cancer and help guide physicians to optimal therapeutic regimens. Researchers have been evaluating the differences in genetics between patients and the correlation of these differences to outcomes following therapy. Patients with predicted poor outcomes may benefit from more aggressive therapy or novel approaches, while patients with predicted good outcomes may be spared from unnecessary treatment and its related side effects.
Researchers from the Netherlands and the U.S. recently conducted a clinical study to determine the accuracy of a genetics test called microarray analysis in determining long-term outcomes of patients with stages I and II breast cancer. This study involved 295 patients who had been diagnosed with breast cancer between 1985 and 995 and were younger than the age of 53. Approximately half of the women in this study had cancer that had spread to their axillary lymph nodes (node positive) and half had no spread (node negative).
According to microarray analysis, 180 women were categorized as having a poor prognosis and 115 women were categorized as having a good prognosis. Ten years following treatment, nearly 95% of patients in the good-prognosis group survived, compared to only approximately 55% in the poor-prognosis group. Cancer recurrence rates were only 15% for patients in the good-prognosis group, compared to over 50% for patients in the poor-prognosis group. Upon evaluation of patient data, microarray analysis was a more accurate predictor of long-term outcomes than the standard clinical systems currently used. It has been estimated that the cost of this genetic test is approximately $1,500; however, medical costs saved from unnecessary therapy may likely exceed this amount.
These authors concluded that genetic microarray analysis is an accurate predictor in the prognosis of young patients with stages I-II breast cancer and may help to individualize therapies in order to provide optimal care for every patient. Women with early-stage breast cancer may wish to discuss the risks and benefits of participating in a clinical trial further evaluating this test or other approaches in predicting prognoses. Two sources of information regarding ongoing clinical trials include the National Cancer Institute (cancer.gov) and www.eCancerTrials.com. eCancerTrials.com also provides personalized clinical trial searches on behalf of patients.
Reference: van de Vijver, M, He Y, van’t Veer L, et al. A gene-expression signature as a predictor of survival in breast cancer.
The New England Journal of Medicine. 2002;347:1999-2009.
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