The influence of radiotherapy on sleep disturbances in breast cancer patients.

1092 Background: Sleep disturbances are distressing and common among breast cancer patients during treatment. However, few studies have examined the impact of radiotherapy (RT) on sleep quality. The goal of this study was to prospectively assess breast cancer patients before, during, and after RT to determine the impact of RT on sleep. Methods: Following breast conserving surgery, 80 breast cancer patients were enrolled on a prospective, longitudinal study of sleep before, during, and after whole breast RT. All patients received a dose of 50 Gy followed by a 10 Gy boost. Subjects completed the Pittsburgh Sleep Quality Index (PSQI) before (i.e., baseline), at week 6 of RT, and 6 weeks after RT completion. Demographic, patient- and treatment-related factors were also recorded. Paired t tests were used to test longitudinal differences in PSQI between time points. Linear mixed models were used to identify predictors of higher PSQI scores and poor sleep (i.e., PSQI score >5). Results: Before, during, and after RT, 61%, 56%, and 59% of subjects were poor sleepers, respectively. PSQI scores did not significantly change during or after RT compared with baseline measures. On univariate analysis, significant predictors of higher PSQI scores were prior chemotherapy treatment, African American race, and having less than a college education (all p<0.01). Tumor stage, axillary lymph node dissection (vs. sentinel lymph node biopsy only), patient age, marital status, and income were not significant predictors of poor sleep. On multivariate analysis, African American race (p<0.006) and having less than a college education (p<0.004) remained significant predictors of higher PSQI scores at each time point. Conclusions: Our findings indicate that sleep disturbances are prevalent during breast cancer treatment. Nevertheless, it appears that RT does not contribute to poor sleep while patient baseline characteristics including African American race and low educational level are associated with higher PSQI scores throughout and after RT. Studies aimed at developing interventions for these patients at risk for sleep disturbances during breast cancer treatment are warranted.