UCSF

ABSTRACT

Objective

The study purposes were to attempt to replicate the association found in our previous study of patients and family caregivers1 between IL6 and sleep disturbance and to identify additional genetic associations in a larger sample of patients with breast cancer.

Design

Descriptive, longitudinal study

Setting

Patients were recruited from breast care centers located in a Comprehensive Cancer Center, two public hospitals, and four community practices.

Participants

Women (n=398) with breast cancer who had surgery on one breast with no distant metastasis.

Measurements

Questionnaires including the Karnofsky Performance Status (KPS) scale and Self-Administered Comorbidity Questionnaire (SCQ). The 21-item General Sleep Disturbance Scale (GSDS) was used to assess sleep disturbance prior to surgery and monthly for 6 months.

Results

Patients who were younger, had lower KPS scores, and more comorbidities were more likely to be in the high sleep disturbance class. Variations in three cytokine genes (i.e., Interleukin 13, Nuclear Factor Kappa Beta 2, and Interleukin 1 receptor 2) predicted latent class membership.

Conclusions

Genetic markers may partially explain inter-individual variability among symptom trajectories. Determination of a high risk phenotype and associated genotypes allows for earlier identification of patients at higher risk for developing sleep disturbance and other behavioral symptoms leading to the development of more targeted clinical interventions.

Key words: Sleep disturbance, breast cancer, cytokine genes, growth mixture modeling, latent class, symptom trajectories.