According to the June 3 issue of BMC Breast Cancer Research, investigators from Copenhagen University Hospital concluded that women with elevated c-reactive protein (CRP) levels at the time of breast cancer diagnosis may have reduced overall and disease-free survival (survival free from cancer) with an increased risk of death. In this largest, prospective study to date, findings suggest that testing for CRP levels at the time of breast cancer diagnosis could help doctors determine severity of the disease and help guide treatment to improve overall survival.
CRP is a protein produced in the liver when stimulated by cytokines, cellular substances that are released in response to an infection or injury. CRP is known as an acute-phase reactant and plays an important role in the immune response. Because tumor sites are often associated with inflammation, elevated CRP levels may be present and have been previously associated with poor treatment outcomes for endometrial, cervical, prostate, and colorectal cancers. It now appears that breast cancer may also fall into this category, though previous, smaller studies have offered conflicting conclusions.
To discern whether elevated levels of CRP at the time of diagnosis with invasive breast cancer are associated with overall survival, recurrence, or death, these researchers studied 2,910 women from the Copenhagen Breast Cancer Study for seven years. The researchers divided the women into three groups based on their plasma CRP levels (measured with a high-sensitivity CRP or hs-CRP assay). Women in the group with the highest levels had greatly reduced odds of achieving disease-free survival and higher likelihood of death than those in the group with the lowest CRP levels.
The overall survival rate for the group with the highest CRP levels was 74% compared to 90% for the group with the lowest levels. Similarly, the disease-free survival rate was 74% for the group with the highest CRP levels compared to 87% for the group with the lowest levels, and the cumulative incidence of death from breast cancer was found to increase with rising CRP levels. However, the rate of recurrence did not significantly escalate with increased CRP levels. The researchers attributed this situation to the relatively small number of women – 118 – who had recurrences and suggested further studies with a larger sample to definitively determine if any relationship exists.
The researchers concluded that CRP tests might be useful in predicting breast cancer outcomes, but were unsure as to why CRP is linked to breast cancer mortality. They hypothesized that increased CRP levels may reflect a patient's overall health at the time of diagnosis, any adjacent inflammation, the tumor’s aggressiveness, or other conditions in the body.
While this study was limited to the measurement of CRP, the relationship with other markers that have been previously associated with poor breast cancer prognosis, such as serum amyloid A, serum albumin, and YKL-40, would require further studies. The researchers also added that their study did not account for other factors, such as socioeconomic status, physical activity levels, type of treatment, or other ethnic groups outside of the Danish women of this study.
Because results of previous, yet smaller studies offer conflicting evidence of the part CRP plays in breast cancer survival, the researchers suggested that further study of the protein's association with breast cancer survival is warranted.
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Fiore, Kristina. Inflammatory Marker May Predict Breast Ca Outcomes. MedPage Today. Available online at http://www.medpagetoday.com/HematologyOncology/BreastCancer/26826?utm_content=&utm_medium=email&utm_campaign=DailyHeadlines&utm_source=WC&userid=238737 through http://www.medpagetoday.com. Published June 3, 2011. Accessed July 5, 2011.
Allin KH, et al. Elevated pre-treatment levels of plasma C-reactive protein are associated with poor prognosis after breast cancer: A cohort study. BMC Breast Cancer Research 2011; DOI: 10.1186/bcr2891. Available online at http://breast-cancer-research.com/content/13/3/R55/abstract through http://breast-cancer-research.com. Accessed July 2011.
C-Reactive Protein Levels Predict Breast Cancer Survival Rates, Study Finds. Science Daily. Available online at http://www.sciencedaily.com/releases/2011/06/110602204202.htm through http://www.sciencedaily.com. Published June 1, 2011. Accessed July 5, 2011.
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