Abstract PD11-04: The impact of sleep on weight loss in overweight or obese breast cancer survivors
Authors: Sheng Jennifer Y , Montanari Amanda K , Blackford Amanda L , Lim David D , Santa-Maria Cesar A , Stearns Vered , Smith Michael T , Coughlin Janelle W 
Published: February 2021

Abstract
BACKGROUND: Sleep disturbance, common in cancer survivors, is associated with obesity, eating behaviors and metabolism, and may impact weight loss treatment outcomes. Weight loss promotion in breast cancer survivors is important because it can potentially decrease cancer recurrence. We have previously demonstrated the efficacy of a behavioral weight loss (BWL) intervention for overweight/obese breast cancer survivors in the POWER-remote breast cancer trial. In the current study we aimed to evaluate the impact of baseline sleep on weight outcomes at 6 and 12 months. We hypothesized that participants with poor sleep at baseline will lose significantly less weight. METHODS: Women with a history of stage 0-III breast cancer, who completed local therapy and chemotherapy, with a body mass index ≥25 kg/m2 were randomized to a self-directed approach or the 12-month POWER-remote intervention, a BWL intervention consisting of telephone-based coaching, online educational materials and tracking of diet, physical activity and weight. Participants completed demographic questionnaires at baseline, and patient-reported outcomes (PROs) at baseline, 6 and 12 months, including the 6-item NIH PROMIS Adult Sleep Disturbance Version 1.0 Short Form, assessing sleep quality, depth, and restoration over the last week. Weight was measured at baseline, 6 and 12 months and % total weight loss (%TWL) was calculated from baseline weight. Those with poor sleep were defined as having a sleep T-score &gt;55, and associations between sleep scores and change in weight at 6 and 12 months were made using a linear regression model, while adjusting for baseline weight. Fisher’s exact test was also used to compare the number of patients who had 5% weight-loss between sleep groups.
RESULTS: A total of 48 women with early stage breast cancer received BWL. Those with poor sleep in the BWL group (n= 16) lost significantly less weight than those with normal sleep in the BWL group (n=32) at both 6 (-4.06% vs -6.77% TWL, p&gt;0.05) and 12 months (-3.87% vs -7.54% TWL, p&gt;0.05), respectively. Similar findings were seen in poor sleepers in the BWL group and attaining 5% weight loss at 6 (p&gt;0.05) and 12 months (p&gt;0.05). There were no significant differences in weight loss outcomes among those in usual care.
CONCLUSION: Breast cancer survivors receiving the weight loss intervention who reported normal sleep at baseline had double the weight loss than those with sleep disturbance at 12 months (-7.54% vs -3.87%). While this is not statistically significant, it is clinically significant and leaves room for further study. These results suggest that sleep may affect weight loss. Updated data, including comparison with control group and analyses by weight loss irrespective of arm, will be reported at the conference. Further studies are need to evaluate the association between baseline sleep and weight loss, and determine if interventions that detect and treat underlying sleep disturbance may augment behavioral interventions for weight loss.
FUNDING: Breast Cancer Research Foundation, Cigarette Restitution Fund
Table 1: Weight Loss Summary in BWL group based on Sleep DisturbanceVariablesPoor sleep (T-score &gt;55)Normal sleep (T-Score &lt;55)TotalSample SizeN = 16N = 32N = 48Baseline Weight - Mean (SD)202.1 (32.26)182.64 (27.73)Weight Loss 6mo. (lbs) - Mean (SD)-8.5 (10.02)-11.58 (11.03)Weight Loss 12mo. (lbs) - Mean (SD)-7.92 (14.61)-12.63 (13.72)Percent change in weight from BL to 6mo. - Mean (SD)-4.06 (4.83)-6.77 (6.45)p&gt;0.05Percent change in weight from BL to 12mo. - Mean (SD)-3.87 (7.29)-7.54 (7.91)p&gt;0.05
Citation Format: Jennifer Y Sheng, Amanda K Montanari, Amanda L Blackford, David D Lim, Cesar A Santa-Maria, Vered Stearns, Michael T Smith, Janelle W Coughlin. The impact of sleep on weight loss in overweight or obese breast cancer survivors [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD11-04.