Kristin V. Reinertsen

A study of body image in long-term breast cancer survivors.

In this controlled postdiagnosis study, the authors examined various aspects of body image of breast cancer survivors in cross‐sectional and longitudinal designs.

Alterations of gene expression in blood cells associated with chronic fatigue in breast cancer survivors

Fatigue is one of the most frequent complaints among breast cancer survivors. However, mechanisms underlying persisting fatigue after end of treatment are poorly understood. To explore whether biological processes underlying persistent fatigue can affect gene expression of blood cells, genome-wide expression analyses were performed on whole blood samples from breast cancer survivors classified as chronic fatigued 2–6 years after diagnosis. Non-fatigued survivors served as controls. Several gene sets involved in plasma- and B-cell pathways differed between the chronic fatigued and the non-fatigued, suggesting that a dysregulation in these pathways is associated with chronic fatigue and that a B-cell-mediated inflammatory process might underlie fatigue. The chronic fatigued also had a higher level of leucocytes, lymphocytes and neutrophiles compared with the non-fatigued, thus further indicating that an activation of the immune system plays a role in the biology of chronic fatigue in breast cancer survivors.

Fatigued breast cancer survivors and gene polymorphisms in the inflammatory pathway

Chronic fatigue (CF) in breast cancer survivors (BCSs) has been associated with increased serum C-reactive protein-levels (CRP), pro-inflammatory cytokines and cytokine gene single nucleotide polymorphisms (SNPs). Still, there are few studies on these topics, and due to small study-cohorts the possibility to adjust for other conditions related to inflammatory processes, e.g. depression, has been limited. In 302 BCSs, examined approximately four years after treatment for breast cancer stage II/III, data on high sensitivity (hs)CRP, leukocytes and mRNA interleukin (IL)1β and IL6R expression, depression and chronic fatigue were available. Three years thereafter, 236 BCSs were re-examined. The associations between fatigue and SNPs in inflammation-related genes; IL1β (rs16944), IL6 (rs1800795), IL6receptor (rs4129267, rs4845617, rs2228145), CRP (rs2794521, rs3091244) were investigated, together with the relations between SNPs in IL6R,IL1β and CRP genes and mRNA blood expression levels of IL6R and IL1β and serum hsCRP-levels, respectively. All analyses were repeated after exclusion of depressed individuals and separating BCSs with persistent fatigue from never-fatigued individuals. Even after exclusion of depressed individuals neither the SNPs nor the mRNA IL1β and IL6R expression levels were associated with chronic or persistent fatigue. In the subset of persistent fatigued and never-fatigued individuals the CRP SNP (rs3091244) was associated with hsCRP level (p=0.02). IL1β and IL6R mRNA expression levels were not related to the IL1β and IL6R genotypes. In a large cohort of BCSs the investigated SNPs in inflammation-related genes were not associated with fatigue, though subset analyses indicated an association between the CRP SNP (rs3091244) and serum hsCRP.

The genetics and epigenetics of fatigue.

Fatigue is a common symptom and includes both physical and mental components. It can be associated with a variety of different syndromes and diseases, but in many cases is not associated with other comorbid conditions. Most humans have experienced acute fatigue in relation to different stressors. Acute fatigue typically decreases as the effect of the triggering factor is reduced and a normal homeostatic balance is restored. Fatigue that persists for 6 months or more is termed chronic fatigue. Chronic fatigue (CF) in combination with a minimum of 4 of 8 symptoms and the absence of diseases that could explain these symptoms, constitute the case definition for chronic fatigue syndrome. In spite of its prevalence, the biology of fatigue is relatively poorly understood and biological markers have not yet been identified. This literature search was performed in PubMed to identify research on the genetics and epigenetics of fatigue. Publications were included if fatigue was a major topic and the topic was combined with genetic and/or epigenetic measurements in adult humans. A total of 40 publications were identified. Although altered functioning in the hypothalamic‐pituitary‐adrenal axis, the serotonergic system, and associations with infectious agents have been identified, the search for genetic or epigenetic markers of fatigue, either in the context of CF or chronic fatigue syndrome (CFS) has been relatively unproductive or, in the case of epigenetics, nonexistent. Although several studies, both hypothesis‐testing and hypothesis‐generating, have been performed to search for biomarkers, they have mostly been underpowered, restricted by the heterogeneity of the phenotype, or limited by an unsystematic study design. To be able to confirm the hypothesis that risk for, or levels of, fatigue are influenced by the genetic or epigenetic background of an individual, studies need to be based on larger sample sizes with a more clearly defined phenotype. Studies need to focus not only on the influence of a single aspect such as single nucleotide polymorphisms (SNPs) or differential gene expression on disease risk or state, but also on the systems biology behind the disease in combination with information on environmental influences and validation of findings in functional studies.

Thyroid Function in Women after Multimodal Treatment for Breast Cancer Stage II/III: Comparison With Controls From a Population Sample

PURPOSE A possible association between thyroid diseases (TD) and breast cancer (BC) has been debated. We examined prevalence and development of TD in women after multimodal treatment for Stage II/III BC compared with women from a general population. Secondarily, we explored the impact of two different radiotherapy (RT) techniques (standardized field arrangements vs. computed tomography [CT]-based dose planning) on TD in BC patients examined 35-120 months after primary BC treatment. METHODS AND MATERIALS A total of 403 BC patients completed a questionnaire about TD and had blood samples taken for analyses of thyroid function. All had undergone postoperative RT with or without (2%) adjuvant systemic treatment. The results in the BC patients were compared with a cancer-free, age-matched control group from a general population (CGr). RESULTS There was higher prevalence of self-reported hypothyroidism in the BC patients as compared with the CGr (18% vs. 6%, p < 0.001). The raised prevalence was predominantly due to a substantial increase in the development of hypothyroidism after BC diagnosis, whereas the prevalence of hypothyroidism before BC diagnosis was similar to that observed in the CGr. Patients treated with CT-based RT showed a trend for increased post-BC development of hypothyroidism as compared with those treated with standardized field arrangements (p = 0.08). CONCLUSIONS Hypothyroidism is significantly increased in women after multimodal treatment for Stage II/III BC. Radiation to the thyroid gland may be a contributing factor. BC patients should be routinely screened for hypothyroidism.

Long-term Cardiac Mortality After Hypofractionated Radiation Therapy in Breast Cancer

PURPOSE To explore very-long-term mortality from ischemic heart disease (IHD) after locoregional radiation therapy of breast cancer (BC) in relation to degree of hypofractionation and other treatment variables. METHODS AND MATERIALS Two hypofractionated regimens used for locoregional radiation therapy for BC from 1975 to 1991 were considered. Patients received 4.3 Gy × 2/week (10 fractions; target dose 43 Gy; n=1107) or 2.5 Gy × 5/week (20 fractions; target dose 50 Gy; n=459). To estimate cardiac doses, radiation fields were reconstructed in a planning system. Time to death from IHD was the endpoint, comparing the groups with each other and with age-matched, cancer-free control individuals, modeled with the Cox proportional hazards model. RESULTS Patients given 4.3 Gy × 10 had an increased risk of dying of IHD compared with both the 2.5 Gy group (hazard ratio [HR] = 2.37; 95% confidence interval [CI]: 1.06-5.32; P=.036) and the control group (HR = 1.59; 95% CI: 1.13-2.23; P=.008). Photon beams for parasternal fields gave an increased risk of dying of IHD compared with electron beams (HR = 2.56; 95% CI: 1.12-5.84; P=.025). Multivariate analysis gave an increased risk for the 4.3-Gy versus 2.5-Gy regimen with borderline significance (HR = 2.90; 95% CI: 0.97-8.79; P=.057) but not for parasternal irradiation. CONCLUSIONS The degree of hypofractionation and parasternal photon beams contributed to increased cardiac mortality in this patient cohort. Differences emerged after 12 to 15 years, indicating the need of more studies with observation time of 2 decades.

SNP in TXNRD2 Associated With Radiation-Induced Fibrosis: A Study of Genetic Variation in Reactive Oxygen Species Metabolism and Signaling

PURPOSE The aim of the study was to identify noninvasive markers of treatment-induced side effects. Reactive oxygen species (ROS) are generated after irradiation, and genetic variation in genes related to ROS metabolism might influence the level of radiation-induced adverse effects (AEs). METHODS AND MATERIALS 92 breast cancer (BC) survivors previously treated with hypofractionated radiation therapy were assessed for the AEs subcutaneous atrophy and fibrosis, costal fractures, lung fibrosis, pleural thickening, and telangiectasias (median follow-up time 17.1 years). Single-nucleotide polymorphisms (SNPs) in 203 genes were analyzed for association to AE grade. SNPs associated with subcutaneous fibrosis were validated in an independent BC survivor material (n=283). The influence of the studied genetic variation on messenger ribonucleic acid (mRNA) expression level of 18 genes previously associated with fibrosis was assessed in fibroblast cell lines from BC patients. RESULTS Subcutaneous fibrosis and atrophy had the highest correlation (r=0.76) of all assessed AEs. The nonsynonymous SNP rs1139793 in TXNRD2 was associated with grade of subcutaneous fibrosis, the reference T-allele being more prevalent in the group experiencing severe levels of fibrosis. This was confirmed in another sample cohort of 283 BC survivors, and rs1139793 was found significantly associated with mRNA expression level of TXNRD2 in blood. Genetic variation in 24 ROS-related genes, including EGFR, CENPE, APEX1, and GSTP1, was associated with mRNA expression of 14 genes previously linked to fibrosis (P≤.005). CONCLUSION Development of subcutaneous fibrosis can be associated with genetic variation in the mitochondrial enzyme TXNRD2, critically involved in removal of ROS, and maintenance of the intracellular redox balance.

Dose distribution in the thyroid gland following radiation therapy of breast cancer-a retrospective study

PurposeTo relate the development of post-treatment hypothyroidism with the dose distribution within the thyroid gland in breast cancer (BC) patients treated with loco-regional radiotherapy (RT).Methods and materialsIn two groups of BC patients postoperatively irradiated by computer tomography (CT)-based RT, the individual dose distributions in the thyroid gland were compared with each other; Cases developed post-treatment hypothyroidism after multimodal treatment including 4-field RT technique. Matched patients in Controls remained free for hypothyroidism. Based on each patients dose volume histogram (DVH) the volume percentages of the thyroid absorbing respectively 20, 30, 40 and 50 Gy were then estimated (V20, V30, V40 and V50) together with the individual mean thyroid dose over the whole gland (MeanTotGy). The mean and median thyroid dose for the included patients was about 30 Gy, subsequently the total volume of the thyroid gland (VolTotGy) and the absolute volumes (cm3) receiving respectively < 30 Gy and ≥ 30 Gy were calculated (Vol < 30 and Vol ≥ 30) and analyzed.ResultsNo statistically significant inter-group differences were found between V20, V30, V40 and V50Gy or the median of MeanTotGy. The median VolTotGy in Controls was 2.3 times above VolTotGy in Cases (ρ = 0.003), with large inter-individual variations in both groups. The volume of the thyroid gland receiving < 30 Gy in Controls was almost 2.5 times greater than the comparable figure in Cases.ConclusionsWe concluded that in patients with small thyroid glands after loco-radiotherapy of BC, the risk of post-treatment hypothyroidism depends on the volume of the thyroid gland.

Blood gene expression profiling of breast cancer survivors experiencing fibrosis

PURPOSE To extend knowledge on the mechanisms and pathways involved in maintenance of radiation-induced fibrosis (RIF) by performing gene expression profiling of whole blood from breast cancer (BC) survivors with and without fibrosis 3-7 years after end of radiotherapy treatment. METHODS AND MATERIALS Gene expression profiles from blood were obtained for 254 BC survivors derived from a cohort of survivors, treated with adjuvant radiotherapy for breast cancer 3-7 years earlier. Analyses of transcriptional differences in blood gene expression between BC survivors with fibrosis (n=31) and BC survivors without fibrosis (n=223) were performed using R version 2.8.0 and tools from the Bioconductor project. Gene sets extracted through a literature search on fibrosis and breast cancer were subsequently used in gene set enrichment analysis. RESULTS Substantial differences in blood gene expression between BC survivors with and without fibrosis were observed, and 87 differentially expressed genes were identified through linear analysis. Transforming growth factor-β1 signaling was identified as the most significant gene set, showing a down-regulation of most of the core genes, together with up-regulation of a transcriptional activator of the inhibitor of fibrinolysis, Plasminogen activator inhibitor 1 in the BC survivors with fibrosis. CONCLUSION Transforming growth factor-β1 signaling was found down-regulated during the maintenance phase of fibrosis as opposed to the up-regulation reported during the early, initiating phase of fibrosis. Hence, once the fibrotic tissue has developed, the maintenance phase might rather involve a deregulation of fibrinolysis and altered degradation of extracellular matrix components.

Coronary calcium score in 12-year breast cancer survivors after adjuvant radiotherapy with low to moderate heart exposure - Relationship to cardiac radiation dose and cardiovascular risk factors

BACKGROUND/PURPOSE We explored the relation between coronary artery calcium (CAC) and cardiac radiation doses in breast cancer survivors (BCS) treated with radiotherapy (RT). Additionally, we examined the impact of other risk factors and biomarkers of coronary artery disease (CAD). MATERIALS AND METHODS 236 BCS (median age 51years [range 30-70], median observation time 12years [9.2-15.7]), treated with 4-field RT of 50GY, were included and examined in 2004 (T1), 2007 (T2) and 2011 (T3) with clinical examination, blood tests and questionnaires. At T3, cardiac computed tomography was performed with quantification of CAC using Agatston score (AS). For 106 patients cardiac dose volume histograms were available. RESULTS The cohort-based median of the mean cardiac dose was 2.5 (range 0.5-7.0) Gy. There was no correlation between measures of cardiac dose and AS. AS was correlated with high cholesterol at T1/T2 (p=0.022), high proBNP at T1/T2 (p<0.022) and T3 (p<0.022) and high HbA1c at T3 (p=0.022). In addition, a high AS was significantly associated with hypertension (p=0.022). Age (p<0.001) and cholesterol at T1/T2 (p=0.001) retained significant associations in multivariate analysis. CONCLUSIONS Traditional, modifiable risk factors of CAD correlate with CAC and may be important for the long term risk of CAD after RT. With low to moderate cardiac radiation exposure, a contribution of radiation dose to CAC could not be demonstrated.