Correlates of Cytokines and Fatigue in Women with Breast Cancer
Breast cancer is the number one cancer diagnosis in women. Treatment often involves chemotherapy after surgical intervention. Cancer related fatigue (CRF) is the most common and distressing symptom related to cancer treatment yet the pathophysiology of this persistent and debilitating symptom remains unknown.
Cancer related fatigue, a multidimensional symptom, is experienced most severely two days post chemotherapy administration. Evidence suggests sickness behavior observed in animal models results from the activation of pro-inflammatory cytokines which is similar to the symptoms such as fatigue experienced by oncology patients receiving chemotherapy. Based on The Cytokine-Immunologic Model of Cancer Symptoms (CIMCS) tumor necrosis factor alpha (TNF-α) was selected as the pro-inflammatory cytokine for this study.
The purpose of this pilot study was to determine the relationships between TNF-α, fatigue levels, and chemotherapy drugs administered for Stage I and II breast cancer. The study was a part of a larger descriptive, correlational, longitudinal pilot study. Blood samples and Piper Fatigue Scale data were collected from 11 women at baseline and days 7, 14, 21, 28 throughout chemotherapy treatment for a total of 216 data points. Enzyme-linked immunosorbant assays (ELISAs) were used to determine TNF-a levels.
Using a general linear mixed model with fatigue as the dependent variable, the independent variables chemotherapy type (F(3,7)=5.60, p=0.0281) and time (F(1,69)=6.74, p=0.0115) were significant at the 0.05 level. The mean fatigue scores (t(7)=3.53, p=0.0097) for chemotherapy 1(mean=4.8645, se=0.7407) and chemotherapy 4(mean=2.6077, se=0.1236) indicates greater fatigue in chemotherapy type 1 versus chemotherapy type 4. Time (sequence of visit) (F(1,69)=6.74, p=0.0115) was a significant predictor of severity of fatigue. Using natural logarithmic transformations significant predictors of Ln(TNF-a were receiving chemo (F(1,7)=5.79, p=0.0471 and chemo type (F(3,7)=9.86, p=0.0066). This model estimates when all else is held constant (a) that not having chemotherapy corresponds with a 34.8% increase in TNF-a level over having chemotherapy, (b) both chemotherapy group 2 and group 3 are significantly different from group 4 on TNF-a, (c) that having chemotherapy group 2 corresponds with a 53.38% increase in TNF-a over having group 4, (d) group 3 corresponds with a 97.9% increase in TNF-a over having group 4.
In summary, the women in this study had significantly different levels of TNF-α and fatigue depending on the type of chemotherapy drugs that were administered and whether or not chemotherapy was administered on that day. The findings related to fatigue are consistent with the literature. Adding the TNF-a results will continue to build the foundation for future nursing interventions to decrease fatigue and improve quality of life for women with breast cancer.
Ingrid H. Kelley, BSN; Honors Thesis, The University of Texas at Arlington, 2011Faculty Mentor:
Barbara M. Raudonis, PhD, RN, FNGNA, FPCN