Lifestyle Intervention and Effect on Disease-free Survival in Early Breast Cancer Pts: Interim Analysis from the Randomized SUCCESS C Study

Background: Recent trials have provided evidence that obesity and a low level of physical activity are not only associated with a higher risk of developing breast cancer, but also with an increased risk for recurrence and reduced survival in breast cancer patients (pts). The SUCCESS C study is the first randomized Phase III trial to evaluate the effect of an intensive lifestyle intervention program, focusing on both physical activity and healthy diet following adjuvant chemotherapy on disease-free survival in women with early breast cancer. Methods: SUCCESS C is a German multicenter, 2×2 factorial design, randomized phase III study comparing disease-free survival (DFS) in pts with HER2-negative early breast cancer treated with either 3 cycles of epirubicine, fluorouracil, cyclophosphamide chemotherapy followed by 3 cycles of docetaxel (FEC-D) or 6 cycles of docetaxel-cyclophosphamide (DC). The second randomization compares DFS in pts with a body mass index (BMI) of 24—40 kg/m2 receiving either a telephone-based individualized lifestyle intervention (LI) program aiming at moderate weight loss for 2 years (LI arm) or general recommendations for a healthy lifestyle alone (non-LI arm). DFS according to lifestyle intervention was analyzed using both univariable cox regressions and multivariable cox regressions adjusted for age (years, continuous), BMI (kg/m2, continuous), menopausal status (premenopausal, postmenopausal), tumor size (pT1, pT2, pT3/pT4), nodal stage (pN0, pN1, pN2, pN3), hormone receptor status (positive, negative), grading (G1, G2, G3), histological type (ductal, lobular, other) and chemotherapy randomization (FEC-D, DC). Median follow-up was 64.2 months. Results: Overall, 2292 of the 3643 pts recruited for the SUCCESS C study were randomized for the lifestyle intervention program (1146 pts in both the non-LI arm and the LI arm). The Intention-to-treat analysis revealed no difference in DFS between the two treatment arms (LI vs. non-LI) in univariable analysis (hazard ratio [HR] 0.99, 95% confidence interval [CI] 0.76 — 1.28, p = 0.922) and in adjusted multivariable cox regression (HR 0.91, 95% CI 0.70 — 1.18, p = 0.48). At the 2-year follow up, pts in the LI arm lost on average 1.0 kg weight compared to the start of the LI program, while pts in the non-LI arm gained on average 0.95 kg (p Conclusions: This explorative and non-planned interim analysis indicates that the completion of a systematic telephone life style intervention program may positively impact patient outcome in early breast cancer. Citation Format: Janni W, Rack BK, Friedl TW, Muller V, Lorenz R, Rezai M, Tesch H, Heinrich G, Andergassen U, Harbeck N, Schochter F, De Gregorio A, Tzschaschel M, Huober J, Hepp P, Fehm TN, Schneeweiss A, Lichtenegger W, Blohmer J, Hauner D, Beckmann MW, Haberle L, Fasching PA, Hauner H. Lifestyle Intervention and Effect on Disease-free Survival in Early Breast Cancer Pts: Interim Analysis from the Randomized SUCCESS C Study [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 GS5-03.