P4-12-05: Impact of the Lifestyle Intervention Study in Adjuvant Treatment of Early Breast Cancer (LISA) Weight Loss Intervention upon Physical Activity.
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AbstractObservational evidence shows a relationship between obesity and poor prognosis in breast cancer (BC). Physical activity (PA) is an important component of weight loss and maintenance, but most large-scale interventions in BC patients have produced only modest improvements in activity. We sought to evaluate changes in PA in women participating in LISA, a randomized trial coordinated by the Ontario Clinical Oncology Group which was designed to examine the impact of a telephone-based weight loss intervention (WLI) upon disease free survival in BC patients.Methods: Participants were randomized 1:1 to the WLI or educational control (EC) group. Eligibility included diagnosis of Stage I-III BC, BMI ≥24 kg/m2, and treatment with letrozole. The WLI, based on the Diabetes Prevention Program, focused on weight reduction through calorie restriction and increased physical activity. Delivery involved 19 calls, mailings and a participant manual. The PA goal was 150 minutes/week. PA was measured using the International Physical Activity Questionnaire (Short Form) at baseline, 6, 12, and 18 months. Changes in time (minutes/week) spent sitting and engaging in moderate, vigorous, and walking activities were compared between groups.Results 338 women were randomized to WLI (n=171) or EC (n=167) from 20 centers in Canada and the USA. The study was discontinued due to loss of funding. The WLI arm lost significantly more weight than EC arm, with mean weight loss of 6.1% of body weight vs. 0.6% at 12 months (p<0.001). Activity data are presented in Table 1. At baseline, participants were inactive; median vigorous activity was zero minutes/week and median time spent sitting was more than 35 hours/week. WLI participants reported significantly higher participation in vigorous, moderate and walking activities, and lower levels of sedentary behavior, compared to controls at 6 and 12 months. Higher levels of PA were significantly associated with increased weight loss at all time periods. Factors associated with increases in activity included higher baseline BMI (p=0.014), lower baseline activity (p<0.001) and assignment to the WLI arm (p=0.02). Women assigned to WLI increased their PA during the intervention period (p=0.017) even after adjusting for other significant baseline factors.Conclusion Participants in the LISA WLI reported significantly higher levels of PA compared with controls. Activity increased most in women who were heavier and less active at baseline. Further study of this WLI as a potential means to improve BC outcomes is warranted.Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-12-05.
