Upper extremity bioimpedance before and after treadmill testing in women post breast cancer treatment.

Research on the effect of cardiorespiratory (CR) exercise on upper extremity (UE) limb volume is limited in women with breast cancer-related lymphedema (BCRL). The aim of this study was to compare changes in UE volume immediately following a symptom-limited CR treadmill test in women with and without BCRL. As part of a cross-sectional study, 133 women post unilateral BC treatment completed symptom-limited treadmill testing. Bioimpedance spectroscopy (BIS) was used to measure UE resistance before and immediately following treadmill testing. Resistance ratios >1 (unaffected side/affected side) indicate greater volume in the affected limb. T-tests and repeated measures ANOVA were performed to evaluate differences between and within groups. Mean age was 56.2 years (SD 9.4); BMI was 26.13 kg m(-2) (SD 5.04). For women with previously diagnosed BCRL (n = 63), the resistance ratio was 1.116 (SD 0.160) pre-treadmill and 1.108 (SD 0.155) post-treadmill. For women without BCRL (n = 70), the resistance ratio was 0.990 (SD 0.041) pre-treadmill and 1.001 (SD 0.044) post-treadmill. Resistance ratios for women with BCRL were higher than those for women without BCRL at both time points (main effect of group: p < 0.001). No main effects were found for time (p = 0.695). A statistically significant effect was found for the time-by-group interaction (p = 0.002). 78% of the women with BCRL wore a compression garment during testing. Following testing, the women with BCRL demonstrated a non-statistically significant decrease in the resistance ratio, suggesting an immediate decrease in interlimb volume difference. The women without BCRL demonstrated an increase in the resistance ratio.

Association between an interleukin 1 receptor, type I promoter polymorphism and self-reported attentional function in women with breast cancer.

Subgroups of patients with breast cancer may be at greater risk for cytokine-induced changes in cognitive function after diagnosis and during treatment. The purposes of this study were to identify subgroups of patients with distinct trajectories of attentional function and evaluate for phenotypic and genotypic (i.e., cytokine gene polymorphisms) predictors of subgroup membership. Self-reported attentional function was evaluated in 397 patients with breast cancer using the Attentional Function Index before surgery and for six months after surgery (i.e., seven time points). Using growth mixture modeling, three attentional function latent classes were identified: High (41.6%), Moderate (25.4%), and Low-moderate (33.0%). Patients in the Low-moderate class were significantly younger than those in the High class, with more comorbidities and lower functional status than the other two classes. No differences were found among the classes in years of education, race/ethnicity, or other clinical characteristics. DNA was recovered from 302 patients' samples. Eighty-two single nucleotide polymorphisms among 15 candidate genes were included in the genetic association analyses. After controlling for age, comorbidities, functional status, and population stratification due to race/ethnicity, IL1R1 rs949963 remained a significant genotypic predictor of class membership in the multivariable model. Carrying the rare "A" allele (i.e., GA+AA) was associated with a twofold increase in the odds of belonging to a lower attentional function class (OR: 1.98; 95% CI: 1.18, 3.30; p=.009). Findings provide evidence of subgroups of women with breast cancer who report distinct trajectories of attentional function and of a genetic association between subgroup membership and an IL1R1 promoter polymorphism.

Mechanosensitivity in the upper extremity following breast cancer treatment.

STUDY DESIGN: Descriptive, cross-sectional. INTRODUCTION: Breast cancer (BC) treatments place the nervous system at risk, which may contribute to upper extremity (UE) mechanosensitivity. PURPOSE OF THE STUDY: To evaluate elbow extension range of motion (EE-ROM) during upper limb neurodynamic testing (ULNT) post-BC treatment. METHODS: ULNT EE-ROM was measured for 145 women post-BC treatment. Women were sub-grouped by presence/absence of pain and lymphedema. RESULTS: Mean EE-ROM during ULNT1 was -22.3° (SD 11.9°) on the unaffected limb and -25.99° (SD 13.1°) on the affected limb. The women with pain and lymphedema had the greatest limitation in EE-ROM during ULNT1 testing, particularly of their affected limb (-33.8°, SD 12.9). Symptoms were reported more frequently in the affected chest, shoulder, arm, elbow, and hand. The intensity of symptoms was greater at the affected chest (p = 0.046), shoulder (p = 0.033) and arm (p = 0.039). CONCLUSIONS: Women with lymphedema and pain after BC treatment may present with altered neural mechanosensitivity. LEVEL OF EVIDENCE: 3a.

Trajectories of Depressive Symptoms in Women Prior to and for Six Months After Breast Cancer Surgery.

Depressive symptoms are common in women with breast cancer. This study evaluated how ratings of depressive symptoms changed from the time of the preoperative assessment to 6 months after surgery and investigated whether specific demographic, clinical, and symptom characteristics predicted preoperative levels of and/or characteristics of the trajectories of depressive symptoms. Characteristics that predicted higher preoperative levels of depressive symptoms included being married/partnered; receipt of adjuvant chemotherapy; more fear of metastasis; higher levels of trait anxiety, state anxiety, sleep disturbance, problems with changes in appetite; more hours per day in pain; and lower levels of attentional function. Future studies need to evaluate associations between anxiety, fears of recurrence, and uncertainty, as well as personality characteristics and depressive symptoms.

Association between pro- and anti-inflammatory cytokine genes and a symptom cluster of pain, fatigue, sleep disturbance, and depression.

Because multiple symptoms associated with "sickness behavior" have a negative impact on functional status and quality of life, increased information on the mechanisms that underlie inter-individual variability in this symptom experience is needed. The purposes of this study were to determine: if distinct classes of individuals could be identified based on their experience with pain, fatigue, sleep disturbance, and depression; if these classes differed on demographic and clinical characteristics; and if variations in pro- and anti- inflammatory cytokine genes were associated with latent class membership. Self-report measures of pain, fatigue, sleep disturbance, and depression were completed by 168 oncology outpatients and 85 family caregivers (FCs). Using latent class profile analysis (LCPA), three relatively distinct classes were identified: those who reported low depression and low pain (83%), those who reported high depression and low pain (4.7%), and those who reported high levels of all four symptoms (12.3%). The minor allele of IL4 rs2243248 was associated with membership in the "All high" class along with younger age, being White, being a patient (versus a FC), having a lower functional status score, and having a higher number of comorbid conditions. Findings suggest that LPCA can be used to differentiate distinct phenotypes based on a symptom cluster associated with sickness behavior. Identification of distinct phenotypes provides new evidence for the role of IL4 in the modulation of a sickness behavior symptom cluster in oncology patients and their FCs.

Identification of distinct subgroups of breast cancer patients based on self-reported changes in sleep disturbance.

PURPOSE: The purposes of this study were to identify distinct subgroups of patients based on self-reported sleep disturbance prior to through 6 months after breast cancer surgery and evaluate for differences in demographic, clinical, and symptom characteristics among these latent classes. METHODS: Women (n = 398) who underwent unilateral breast cancer surgery were enrolled prior to surgery. Patients completed measures of functional status, sleep disturbance (i.e., General Sleep Disturbance Scale (GSDS); higher scores indicate higher levels of sleep disturbance), fatigue, attentional fatigue, depressive symptoms, and anxiety prior to surgery and monthly for 6 months. RESULTS: Three distinct classes of sleep disturbance trajectories were identified using growth mixture modeling. The high sustained class (55.0%) had high and the low sustained class (39.7%) had low GSDS scores prior to surgery that persisted for 6 months. The decreasing class (5.3%) had high GSDS score prior to surgery that decreased over time. Women in the high sustained class were significantly younger, had more comorbidity and poorer function, and were more likely to report hot flashes compared to the low sustained class. More women who underwent mastectomy or breast reconstruction were in the decreasing class. Decreasing and high sustained classes reported higher levels of physical fatigue, attentional fatigue, depressive symptoms, and anxiety compared to the low sustained class. CONCLUSIONS: A high percentage of women has significant sleep disturbance prior to surgery that persists during subsequent treatments (i.e., radiation therapy and chemotherapy). Clinicians need to perform routine assessments and initiate appropriate interventions to improve sleep prior to and following surgery.

A randomized clinical trial of granulocyte macrophage colony stimulating factor mouthwash for oral mucositis in head and neck cancer.

PURPOSE: Oral mucositis (OM) is a significant problem for patients with head and neck cancer (HNC). The purpose of this double-blind, randomized clinical trial (RCT) was to evaluate the effectiveness of the granulocyte macrophage colony stimulating factor (GM-CSF) mouthwash compared to Salt and Soda mouthwash for both the prevention (prior to onset of OM) and treatment (beginning at the onset of OM to its healing) of radiation therapy (RT)-induced OM. METHODS: A total of 91 patients with HNC were randomized to receive: GM-CSF throughout both the prevention and treatment phases (GG group); Salt and Soda throughout both phases (SS group) or Salt and Soda during the prevention phase followed by GM-CSF at the onset of OM (SG group). Three groups were compared on the occurrence and grades of OM, functional status, pain, chewing, and swallowing during and after RT. RESULTS: No significant differences were found in the occurrence and grades of OM in the patients who used GM-CSF vs. Salt and Soda in the prevention phase. In addition, no differences were seen among the three groups in functional status, pain, chewing, and swallowing during and after RT. CONCLUSION: Given that GM-CSF was no more effective than Salt and Soda mouthwash for the prevention or treatment of OM, the readily available and cheaper mouthwash can be used at considerable cost savings.

Advances in Conceptual and Methodological Issues in Symptom Cluster Research: A 20-Year Perspective.

Two conceptual approaches are used to evaluate symptom clusters: "clustering" symptoms (ie, variable-centered analytic approach) and "clustering" patients (ie, person-centered analytic approach). However, these methods are not used consistently and conceptual clarity is needed. Given the emergence of novel methods to evaluate symptom clusters, a review of the conceptual basis for older and newer analytic methods is warranted. Therefore, this article will review the conceptual basis for symptom cluster research; compare and contrast the conceptual basis for using variable-centered versus patient-centered analytic approaches in symptom cluster research; review their strengths and weaknesses; and compare their applications in symptom cluster research.

A prospective longitudinal study of chemotherapy-induced cognitive changes in breast cancer patients.

PURPOSE: Evidence for chemotherapy-induced cognitive impairment remains inconclusive. This study was designed to determine the trajectory of cognitive function over time in women with breast cancer, who received doxorubicin and cyclophosphamide (AC) alone or followed by a taxane. Associations between changes in cognitive function and potential covariates including anxiety, depression, fatigue, hemoglobin level, menopausal status, and perception of cognitive function were evaluated. METHODS: The Repeatable Battery for the Assessment of Neuropsychological Status, Stroop Test, and Grooved Pegboard were used to assess cognitive function in a group of 71 women prior to chemotherapy, a week after completing the last cycle of AC, as well as 1 week and 6 months after the completion of all chemotherapy. RESULTS: Cognitive impairment was found in 23% of women prior to chemotherapy. Hierarchical linear modeling showed significant decreases after receiving chemotherapy followed by improvements 6 months after the completion of chemotherapy in the cognitive domains of visuospatial skill (p < 0.001), attention (p = 0.022), delayed memory (p = 0.006), and motor function (p = 0.043). In contrast, immediate memory, language, and executive function scores did not change over time. CONCLUSION: These results suggest that having a breast cancer diagnosis may be associated with cognitive impairment. While chemotherapy may have a negative impact on cognitive function, chemotherapy-related impairments appear to be more acute than chronic side effects of therapy. Further studies are needed to provide insight into the clinical significance and potential mechanisms of cancer and treatment-related cognitive impairments.

An evaluation of the factors that affect the health-related quality of life of children following myelosuppressive chemotherapy.

PURPOSE: The purposes of this study, in children who were assessed 1 week after the administration of myelosuppressive chemotherapy were: to compare the total and subscale scores on a generic measure of health-related quality of life (HRQOL) to normative data from healthy children and describe the relationships between demographic, clinical, and symptom characteristics of children with cancer and generic and disease-specific dimensions of HRQOL. METHODS: Patients (n = 61) were predominantly male (52.5%), minority (63.9%), and 14.7 years of age. Children completed the Memorial Symptom Assessment Scale for 10- to 18-year olds, the PedsQL™ Generic and Cancer Modules, and the Karnofsky Performance Status (KPS) scale 1 week after the start of a chemotherapy cycle. RESULTS: The mean number of symptoms per patient was 10.6. Compared with the normative sample, children with cancer reported significantly lower scores for the total scale and all of the subscales except emotional and social functioning. No significant differences were found between any demographic characteristics and total or subscale scores on the generic or disease-specific measures of HRQOL. Lower KPS scores were associated with poorer generic and disease-specific HRQOL scores. In addition, a higher number of symptoms was associated with poorer generic and disease-specific HRQOL scores. Finally, higher symptom distress scores were associated with poorer generic and disease-specific HRQOL scores. CONCLUSION: Among the demographic, clinical, and symptom characteristics studied, poorer functional status and higher symptom burden were associated with significant decreases in HRQOL in children who received myelosuppressive chemotherapy.

Comparison of diagnostic accuracy of clinical measures of breast cancer-related lymphedema: area under the curve.

OBJECTIVE: To compare diagnostic accuracy of measures of breast cancer-related lymphedema (BCRL). DESIGN: Cross-sectional design comparing clinical measures with the criterion standard of previous diagnosis of BCRL. SETTING: University of California San Francisco Translational Science Clinical Research Center. PARTICIPANTS: Women older than 18 years and more than 6 months posttreatment for breast cancer (n=141; 70 with BCRL, 71 without BCRL). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Sensitivity, specificity, receiver operator characteristic curve, and area under the curve (AUC) were used to evaluate accuracy. RESULTS: A total of 141 women were categorized as having (n=70) or not having (n=71) BCRL based on past diagnosis by a health care provider, which was used as the reference standard. Analyses of ROC curves for the continuous outcomes yielded AUC of .68 to .88 (P<.001); of the physical measures bioimpedance spectroscopy yielded the highest accuracy with an AUC of .88 (95% confidence interval, .80-.96) for women whose dominant arm was the affected arm. The lowest accuracy was found using the 2-cm diagnostic cutoff score to identify previously diagnosed BCRL (AUC, .54-.65). CONCLUSIONS: Our findings support the use of bioimpedance spectroscopy in the assessment of existing BCRL. Refining diagnostic cutoff values may improve accuracy of diagnosis and warrant further investigation.

Predictors of exercise frequency in breast cancer survivors in Taiwan.

AIM: To apply social cognitive theory to elucidate factors that motivate change in exercise frequency in breast cancer survivors during the six months after completing cancer treatment. BACKGROUND: Exercise is now a well-recognised quality-of-life intervention in breast cancer survivors. However, only regular exercise yields long-term benefits. Motivations for exercise have not been analysed in Taiwan patients with cancer. DESIGN: A prospective, longitudinal and repeated measures design was used. METHODS: A convenience sample of 196 breast cancer survivors was recruited from hospitals in metropolitan areas of north and south Taiwan. Study participants were allowed to select their preferred exercised activities. Exercise behaviour and other factors were then recorded using various standardised instruments. Medical charts were also reviewed. Data were analysed by a linear mixed model and by hierarchical multiple regression equations. RESULTS: Exercise frequency significantly changed over time. Explained variance in exercise frequency change was modest. Baseline exercise frequency was the best significant predictor of exercise frequency during the six-month study. The study also identified possible age-related differences in the effect of social support on exercise. The effect of social support for exercise on exercise frequency was apparently larger in older subjects, especially those over 40 years old, than in younger subjects. Mental health, exercise barriers and exercise outcome expectancy significantly contributed to change in exercise frequency during the six-month study. CONCLUSIONS: The analytical results revealed several ways to increase exercise frequency in breast cancer survivors: (1) encourage exercise as early as possible; (2) improve health status and provide social support for exercise, especially in women aged 40 years or older; (3) reduce exercise barriers and promote mental health; (4) reinforce self-efficacy and positive expectations of exercise outcomes and (5) provide strategies for minimising fatigue in early stages of rehabilitation. Relevance to clinical practice. Social cognitive theory provides a useful framework for understanding the motivation to exercise in breast cancer survivors.

Factors affecting hope in a sample of fatigued breast cancer outpatients.

OBJECTIVE: The aims of this study of women with breast cancer were: to describe the levels of hope and compare hope scores for these patients with a sample from the general Norwegian population; to describe the relationship between hope and fatigue; and finally to evaluate the effect of demographic and clinical characteristics and fatigue on hope. METHOD: A total of 160 Norwegian outpatients with cancer and fatigue (>2.5 on a 0-10 scale) completed the Herth Hope Index (HHI), Fatigue Questionnaire (FQ), and Self-administered Comorbidity Questionnaire (SCQ). RESULTS: The mean age of the women was 55.3 years (SD = 9.4), 81% lived with someone, and 67% were employed. The most common comorbidities were back pain (42%), osteoarthritis (26%), and headache (19%). The fatigued breast cancer patients reported significantly higher total hope scores than the general Norwegian population (p < .0001). The difference was largest in the individual item "I can see a light in the tunnel," to which the cancer sample reported the highest scores, but they also felt more "scared about the future." Total hope score was negatively correlated with total fatigue (TF), mental fatigue (MF), and chronic fatigue (CF), but not with physical fatigue (PF). Demographic and clinical characteristics were not significantly related to hope, except that patients who were married or living with someone showed significantly higher total hope scores. SIGNIFICANCE OF RESULTS: The higher levels of hope in breast cancer patients compared with the general Norwegian population may reflect a response shift in patients after getting a cancer diagnosis. The fact that a significant relationship was found between total hope scores and living arrangements may indicate that hope is easier to establish when patients have someone to relate to or receive support from. Hope and total fatigue were significantly, but weakly correlated.

Changes in symptom clusters in patients undergoing radiation therapy.

GOALS OF WORK: The goals of the study were to determine the occurrence rates for and the severity of symptoms at the middle, end, and 1 month after the completion of radiation therapy (RT), to determine the number and types of symptom clusters at these three time points, and to evaluate for changes over time in these symptom clusters. MATERIALS AND METHODS: Symptom occurrence and severity were evaluated using the Memorial Symptom Assessment Scale (MSAS) in a sample of patients (n = 160) who underwent RT for breast or prostate cancer. At each time point, an exploratory factor analysis was done to determine the number of symptom clusters (i.e., symptom factors) based on the MSAS symptom severity ratings. MAIN RESULTS: The majority of the patients were male and married with a mean age of 61.1 years. The five symptoms with the highest occurrence rates across all three time points were lack of energy, pain, difficulty sleeping, feeling drowsy, and sweats. Although the number of symptoms and the specific symptoms within each symptom cluster were not identical across the three time points, three relatively similar symptom clusters (i.e., "mood-cognitive" symptom cluster, "sickness-behavior" symptom cluster, "treatment-related", or "pain" symptom cluster) were identified in this sample. The internal consistency coefficients for the mood-cognitive symptom cluster and sickness-behavior symptom cluster were adequate at > or =0.68. CONCLUSIONS: Three relatively stable symptom clusters were found across RT. The majority of the symptom cluster severity scores were significantly higher in patients with breast cancer compared to patients with prostate cancer.

Preliminary evidence of a genetic association between tumor necrosis factor alpha and the severity of sleep disturbance and morning fatigue.

Although fatigue and sleep disturbance are prevalent symptoms in oncology patients and their family caregivers, little is known about the factors that contribute to interindividual variability in symptom severity ratings as well as in their underlying biological mechanisms. In this study, we sought to determine whether a functional genetic variation in a prominent proinflammatory cytokine, tumor necrosis factor-alpha (TNFA-308G>A [rs1800629] promoter polymorphism) was associated with overall ratings of sleep disturbance and fatigue as well as with the trajectories of these symptoms. Over 6 months, participants completed standardized measures of sleep disturbance and fatigue. Multiple linear regression was used to assess the effect of the TNFA genotype and other covariates on mean sleep disturbance and fatigue scores. Hierarchical linear modeling was used to determine the effect of TNFA genotype on the trajectories of these symptoms. Common allele homozygotes reported higher levels of sleep disturbance (p=.09) and morning fatigue (p=.02) than minor allele carriers. Multivariate analyses demonstrated that age and genotype were predictors of both mean symptom scores and the trajectories of these symptoms. Findings provide preliminary evidence of an association between a functional promoter polymorphism in the TNFA gene and the severity of sleep disturbance and morning fatigue in oncology patients and their family caregivers.

Trajectories of fatigue in family caregivers of patients undergoing radiation therapy for prostate cancer.

Predictors of and trajectories for evening and morning fatigue were evaluated in family caregivers of oncology patients using hierarchical linear modeling. Evening fatigue trajectory fit a quadratic model. Predictors included baseline sleep disturbances in family caregivers and baseline evening fatigue in patients. Morning fatigue trajectory fit a linear model. Predictors were baseline trait anxiety, levels of perceived family support, and baseline morning fatigue in patients. Findings suggest considerable inter-individual variability in the trajectories of evening and morning fatigue. Evaluating family caregivers for sleep disturbance, anxiety, and poor family support, as well as high levels of patient fatigue, could identify those family caregivers at highest risk for sustained fatigue trajectories.

Research Agenda of the Oncology Nursing Society: 2019-2022.

PROBLEM STATEMENT: To define the Oncology Nursing Society Research Agenda for 2019-2022. DESIGN: Multimethod, consensus-building approach by members of the Research Agenda Project Team. DATA SOURCES: Expert opinion, literature review, surveys, interviews, focus groups, town hall, and review of research priorities from other cancer care organizations and funding agencies. ANALYSIS: Content analysis and descriptive statistics were used to synthesize research priority themes that emerged. FINDINGS: Three priority areas for scientific development were identified. IMPLICATIONS FOR NURSING: The Research Agenda can be used to focus oncology nurses' research, scholarship, leadership, and health policy efforts to advance quality cancer care, inform research funding priorities, and align initiatives and resources across the ONS enterprise.

Preliminary results of a longitudinal study of changes in cognitive function in breast cancer patients undergoing chemotherapy with doxorubicin and cyclophosphamide.

OBJECTIVES: Recent studies suggest that standard dose chemotherapy for breast cancer may cross the blood-brain barrier. However, the evidence for chemotherapy-induced cognitive impairments in breast cancer patients is inconsistent. The purposes of this study in a sample of newly diagnosed patients with breast cancer were to (1) evaluate cognitive function prior to the administration of chemotherapy; (2) assess changes in cognitive function over time; and (3) evaluate potential relationships between cognitive function and anxiety, depression, fatigue, hemoglobin level, menopausal status, and perception of cognitive function. METHODS: Thirty women with breast cancer completed neuropsychological testing before the initiation of chemotherapy and after four cycles of doxorubicin and cyclophosphamide. Descriptive statistics were used to summarize sample characteristics, and paired t-tests were carried out to evaluate for changes in neuropsychological test scores prior to and following completion of chemotherapy. Linear mixed model analyses were used to determine whether significant changes in neuropsychological test scores remained after controlling for anxiety, depression, fatigue, hemoglobin level, menopausal status, and perceived cognitive function. RESULTS: Significant decreases in visuospatial skill (p<0.001) and total cognitive scores (p=0.001) were found following chemotherapy. In addition, a significant improvement was found in executive function (p=0.014). Of note, these changes remained significant even after controlling for anxiety, depression, fatigue, hemoglobin level, menopausal status, and perceived cognitive function. CONCLUSIONS: Data from this study supported the hypothesis that chemotherapy may have a negative impact on select domains of cognitive function.

Trajectories of fatigue in men with prostate cancer before, during, and after radiation therapy.

Fatigue is the most common and distressing symptom reported by patients undergoing radiation therapy (RT). However, limited information is available on the trajectories of fatigue, as well as on the predictors of interindividual variability in fatigue. This study evaluated a sample of patients who underwent RT for prostate cancer to examine how ratings of evening and morning fatigue changed from the time of simulation to four months after the completion of RT and to investigate whether specific patient, disease, and symptom characteristics predicted the initial levels of fatigue and/or characteristics of the trajectories of evening and morning fatigue. Using hierarchical linear modeling, a large amount of interindividual variability was demonstrated in the trajectories of evening and morning fatigue. Findings from this study suggest that younger men with a higher level of fatigue at the time of the simulation visit were at increased risk for higher levels of evening and morning fatigue over the course of RT. In addition, the level of morning fatigue over the course of RT appears to depend on the patient's level of depression at the time of the simulation visit. In future studies, the use of hierarchical linear modeling as an analytic tool will assist in the identification of patients who are most at risk for prolonged fatigue trajectories. This type of analysis may lead to the identification of subgroups of patients who are at higher risk for negative outcomes and who require different types of interventions for the fatigue associated with RT.

Conceptual issues in symptom clusters research and their implications for quality-of-life assessment in patients with cancer.

The majority of the research on the various aspects of symptom management has focused on individual symptoms. However, patients with cancer often experience multiple symptoms simultaneously as a result of their disease and treatment. In 2001, symptom management researchers began to study the impact of symptom clusters on patient outcomes. Over the past 6 years, a number of conceptual reviews as well as several research studies have been published on symptom clusters in oncology patients. This paper summarizes the conceptual basis for symptom cluster research, describes two conceptual approaches to symptom cluster research, and discusses the implications of symptom clusters for quality-of-life research. The paper concludes with an enumeration of the critical considerations that need to be addressed if this area of scientific inquiry is to move forward.