Steindorf, K., Wiskemann, J., Ulrich, C.M., & Schmidt, M.E. (2017). Effects of exercise on sleep problems in breast cancer patients receiving radiotherapy: A randomized clinical trial. Breast Cancer Research and Treatment, 162, 489–499.

The study goals were to (a) identify determinants of sleep disturbances in patients with breast cancer (BC) before radiotherapy, (b) determine the trajectory of sleep disturbances during radiotherapy and at 12-month follow-up, and (c) assess whether an exercise intervention could affect sleep trajectories.

The exercise intervention consisted of eight progressive resistance exercises (3 sets, 8–12 repetitions at 60%–80% of one repetition maximum). The relaxation control group did progressive muscle relaxation according to the Jacobson method. Both interventions were supervised and performed over approximately one hour twice weekly for 12 weeks along with other patients with cancer.

• N = 160 patients with BC; 25 controls (healthy women) 
• AGE: Patients with BC M = 55.6 (SD = 9.0); healthy women M = 53.1 (SD = 10.0)
• FEMALES: 100%
• CURRENT TREATMENT: Radiation, other
• KEY DISEASE CHARACTERISTICS: Stage 0-III primary BC after lumpectomy or mastectomy and scheduled for radiotherapy; 51% diagnosed in stage 1; 67.8 mean days since surgery 
• OTHER KEY SAMPLE CHARACTERISTICS: Average BMI = 26.9 kg/m²; 21.3% had BMI ≥ 30; majority reported little engagement in exercise before BC diagnosis.

• SITE: Single site    
• SETTING TYPE: Hospital outpatient clinic     
• LOCATION: Germany

PHASE OF CARE: Active antitumor treatment

Prospective randomized controlled intervention trial with attention control (relaxation) and healthy control

• Fatigue Assessment Questionnaire (FAQ), a self-report (in past week) of global sleep assessment using a single item indicating sleep disturbance with a 4-point Likert scale
• EORTC-QLQ-C30 insomnia subscale
• Sleep-related characteristics: sleep duration (hours per night), number of awakenings per night, daytime napping (minutes), frequency per week of sleep problems (> 30 minute sleep onset, trouble staying asleep, too early awakenings) using 5 categories (never, 1-2 days, 3-4 days, 5-6 days, all days)  
• Sleep measures were completed at 6 time-points: before intervention/radiotherapy (t0), after 6 weeks (t1), after 12 weeks (t2), and at 2, 6, and 12 months postintervention (t3, t4, t5).

Higher prevalence of sleep disturbances were observed among patients with BC who had previous chemotherapy, higher BMI and depressive symptoms, previous hysterectomy, degenerative diseases, thyroid disorders, and higher symptom burden (hot flashes, pain, breast or arm problems, dyspnea). Patients with BC experienced higher levels of sleep disturbance at all times, but the trajectory of sleep disturbances in exercising women was similar to healthy women. The exercise intervention significantly decreased sleep disturbances compared to the relaxation control group on a 0–100 scale (between-group mean differences of -10.2; p = 0.03) from baseline to the end of radiotherapy and -10.9 (p = 0.005) to the end of the intervention). Sleep disturbances decreased in the exercise group and increased in the control group. At 12 months, differences were observed but not statistically significant (mean difference = -5.9, p = 0.20) even after adjusting for potential confounders.

This exercise intervention trial supports the findings of smaller studies that radiotherapy worsens sleep disturbances in patients with BC compared to healthy women. Findings suggest that a 12-week resistance training during radiotherapy can have positive effects on sleep disturbances during the treatment phase and even months after treatment completion.

• Risk of bias (no blinding)
• Risk of bias (sample characteristics)
• Measurement or methods not well described
• Measurement validity or reliability questionable
• Other limitations/explanation: Measurement or methods not well described in this secondary analysis of the “BEST” study (unable to determine sample demographics, blinding, and protocol fidelity in this publication or other referenced earlier publications)

Sleep quality is associated with quality of life in patients with cancer. These findings about determinants of sleep disturbance, the course sleep disturbance during radiotherapy, and the effect of an exercise intervention are of significance to many patients with BC.