UCSF

ABSTRACT

Symptom Clusters in Patients With Breast Cancer Undergoing Chemotherapy

The first study on symptom clusters in oncology patients was published more than 16 years ago. A symptom clusters is defined as two or more symptoms that are related to each other and that co-occur. In addition, symptom clusters are composed of stable groups of symptoms that are relatively unrelated to other clusters.

Patients with breast cancer, who underwent chemotherapy (CTX), experienced between 10 and 32 concurrent symptoms. An evaluation of how these symptoms cluster together and how these symptom clusters change over time may provide insights into how to treat these multiple co-occurring symptoms.

One of the unanswered questions in symptom clusters research is whether the number and types of symptom clusters vary based on the dimension of the symptom experience used to create the clusters. Given that patients with breast cancer receiving CTX, report a wide range of symptoms and that studies investigated symptom clusters in these patients are limited, the purposes of this dissertation study, in a sample of patients with breast cancer who underwent CTX (n=540), were to: summarize the current state of knowledge of symptom clusters research from studies that included patients who received primary or adjuvant CTX; determine the occurrence rates and severity ratings for 38 common symptoms; evaluate for differences in the number and types of symptom clusters; and evaluate for changes over time in these symptom clusters (i.e., prior to CTX, the week following CTX, and two weeks following CTX).

Patients completed a self-report questionnaire using the Memorial Symptom Assessment Scale (MSAS). The MSAS was used to assess the occurrence and severity of 38 symptoms prior to the next dose CTX, during the week after CTX administration, and approximately two weeks after CTX administration. Exploratory factor analyses (EFAs) were used to extract the symptom clusters.

Across the two symptom dimensions (i.e., occurrence, severity) and the three symptom assessments, while eight distinct symptom clusters were identified, only five were relatively stable across both dimensions and across time (i.e., psychological, hormonal, nutritional, gastrointestinal, epithelial). Two additional clusters varied by time but not by symptom dimension (i.e., sickness behavior, weight change). In addition, a CTX neuropathy cluster was identified only at the assessment done in the week following CTX administration. The most common symptoms within each cluster were relatively stable across the two dimensions and across time.

The identification of symptom clusters in patients with breast cancer undergoing CTX may be useful in guiding symptom management interventions.