Abstract PD6-04: Lifestyle intervention study (LISA) in early breast cancer (BC): An RCT of the effects of a telephone-based weight loss intervention (with educational materials) vs educational materials alone on disease-free survival (DFS)
Authors: Goodwin PJ , Segal R , Vallis M , Ligibel JA , Pond GR , Robidoux A , Findlay BP , Gralow JR , Mukherjee SD , Levine MN , Pritchard KI 
Published: May 2019

Abstract
Background: Obesity has been associated with poor BC outcomes. We investigated whether a standardized, telephone-based weight loss lifestyle intervention in recently diagnosed BC patients would lower recurrence and death rates.
Methods: We conducted a multicenter RCT comparing mail-based educational material alone (control arm) or combined with a standardized, telephone-based lifestyle intervention (19 calls over 2 years, (intervention arm) that focused on diet (500-100 kcal/day deficit), physical activity (150-200 minutes of moderate-intensity activity per week) and behavior (compliance, relapse prevention) to achieve up to 10% weight loss. 338 (of 2150 planned) T1-3, N0-3, M0 ER/PgR+ BC patients with body mass index (BMI) ≥ 24 kg/m2 receiving adjuvant letrozole were randomized Aug 2007 to Jan 2010 (enrolment ended due to funding loss). Primary outcome was DFS; secondary outcome OS. Weight loss (5.3 vs 0.7% at 6 months and 3.6 vs 0.4% at 24 months in the intervention vs control arms, respectively) has been reported (JCO 2014;32:2331). At 8 years median follow-up (May 2018), DFS and OS were compared using Cox proportional hazards regression.
Results: Mean age was 61.6 vs 60.4 years, mean BMI 31.4 vs 31.0 kg/m2 and adjuvant chemotherapy was received by 56.1 vs 57.5% in intervention vs controls arms respectively. T1/T2/T3 66.7/27.5/5.9% vs 61.7/33.5/3.6% and N0/1/2+ 62.6/28.7/8.8 vs 63.5/32.3/4.2% in intervention vs controls arms respectively. HER2+ in 8.8 vs 15.0% (intervention vs control). 20 of 171 (11.7%) in the lifestyle intervention arm vs 30 of 167 (18.0%) in the mail-based arm had DFS events, HR 0.71, 95%CI 0.41-1.24, p=0.23). DFS curves separated at 2 yrs; beyond 3-3.5 yrs separation approximated 5%. In a landmark DFS analysis of women alive at 24 months, DFS HR=0.68 (0.34-1.37, p=0.28).
Conclusions: We identified fewer DFS events in the lifestyle intervention arm. Although loss of funding reduced sample size and lowered power, these results are consistent with a potential beneficial effect of a lifestyle intervention on DFS in postmenopausal ER/PgR+ BC patients. They provide strong support for completion of ongoing RCTs (e.g. BWEL) that will provide definitive evidence regarding the effect of lifestyle based weight loss on BC outcomes.
Funded by Novartis Pharmaceuticals Inc.; Sponsored by the Ontario Clinical Oncology Group
Citation Format: Goodwin PJ, Segal R, Vallis M, Ligibel JA, Pond GR, Robidoux A, Findlay BP, Gralow JR, Mukherjee SD, Levine MN, Pritchard KI. Lifestyle intervention study (LISA) in early breast cancer (BC): An RCT of the effects of a telephone-based weight loss intervention (with educational materials) vs educational materials alone on disease-free survival (DFS) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD6-04.