Crane, Tracy E.

Abstract Background: Obesity is a poor prognostic factor in early breast cancer (BC). The BWEL trial (Alliance A011401; NCT02750826) is a phase 3 randomized trial testing the impact of a weight loss intervention (WLI) on invasive disease-free survival in women with stage II-III BC and a body mass index (BMI) ≥27 kg/m2. Here we report trajectories of weight change in BWEL WLI participants (pts). Methods: Eligible pts were within 16 months of diagnosis of stage II-III HER2-negative BC, had completed chemotherapy (chemo) and radiation (if given), and were randomized 1:1 to a telephone-based WLI, focused on caloric restriction and exercise, plus health education (HE) or to an HE-alone control group. WLI pts were assigned a trained coach at the BWEL call center and received 42 phone calls over the 2-year (yr) WLI period. Weight and height at baseline, 6 and 24 months were collected by study staff. All WLI pts were provided with a Fitbit wireless scale. Fitbit weight records (FWRs) were automatically imported to the BWEL portal for pts with wireless access and self-reported in the portal for pts without wireless access. FWRs were averaged (avg) by week (wk) from the WLI start date up to 104 wks. Baseline pt factors were self-reported; treatment history was abstracted from the medical record. Linear mixed-effect models were used to evaluate trajectories of weight change over the 104-wk WLI. Principal component analysis and multinomial models were used to examine distinct clusters of weight trajectories. Results: 3180 pts were enrolled from 637 sites between 8/2016 and 2/2021. FWRs were available from 1508 of 1591 WLI pts, with a total of 366,294 FWRs collected during the 2-yr WLI period. In pts with FWRs, mean baseline BMI was 34.4 ± 5.6 kg/m2, mean age was 53.2 ± 10.3 yrs, 10.8% self-identified as Non-Hispanic (NH) Black and 6.1% as Hispanic, 81.1% received chemo and 56.9% were postmenopausal. No statistically significant differences in baseline factors were observed between pts with and without FWRs. Intraclass correlation coefficient of baseline weights collected by study staff and by Fitbit scales was 0.99. In the WLI cohort, avg weekly weight (kg) decreased from 91.4 (95% CI: 90.6-92.3) at baseline to 85.6 (95% CI: 84.8-86.5) by wk 40, corresponding to a peak loss of 6.1% (95% CI: 5.7-6.4) of baseline weight. Weight remained stable until wk 52 and then gradually increased to 87.0 kg (95% CI: 86.2-87.9) at wk 104, corresponding to a 4.4% (95% CI: 4.0-4.8) loss at wk 104 vs. baseline. Principal component analysis identified 3 distinct weight trajectories: 67.6% of pts experienced peak weight loss of 6.6% (95% CI: 6.3-6.9) of baseline weight, 10.0% experienced peak loss of 17.5% (95% CI: 16.8-18.2) of baseline weight, and 22.4% did not achieve weight loss, gaining on avg 2.2% (95% CI: 1.7-2.6) of baseline weight. Pts with college (relative risk ratio [RRR]=1.41, 95% CI: 1.03-1.92) and post-graduate education (RRR= 1.58, 95% CI: 1.13-2.20) and those who were premenopausal (RRR=1.70, 95% CI: 1.28-2.26) were more likely to be in the cluster that did not lose weight. Pts who were NH White (RRR=3.60, 95% CI: 1.95-6.68), postmenopausal (RRR=1.94, 95% CI: 1.28-2.95), had no alcohol use (RRR=1.49, 95% CI: 1.03-2.16), had not received chemo (RRR=1.76, 95% CI: 1.15-2.72), and had <3 chronic conditions (RRR: 2.12, 95% CI: 1.23-3.66) were more likely to be in the cluster with the highest weight loss. Conclusion: Longitudinal weight data from BWEL demonstrate peak weight loss of 6.1% in the WLI cohort at 40 wks, with distinct trajectories indicating differential responses to the WLI. This work demonstrates the feasibility of using digital health tools to track outcomes in the setting of a large-scale weight loss intervention study and informs future precision behavioral interventions in oncology. Support: U10CA180821, U10CA180882, UG1CA189823; U10CA180863. https://acknowledgments.alliancefound.org. Citation Format: C. Cao, K. Ballman, L. McCall, C. Alfano, V. Bernstein, T. Crane, L. Delahanty, L. Frank, P. Goodwin, O. Hahn, D. Hershman, J. Hopkins, M. Irwin, E. Mayer, L. Minasian, L. Nebeling, M. Neuhouser, E. Paskett, P. Spears, V. Stearns, C. Thomson, T. Wadden, A. Weiss, J. White, C. Hudis, E. Winer, A. Partridge, L. Carey, J. Ligibel. Weight Trajectories in the Breast Cancer Weight Loss (BWEL) Trial (Alliance) [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PD8-01.

Abstract Background Several ovarian cancer studies have suggested that a body mass index (BMI) of 30 or higher is associated with lower compliance with National Comprehensive Cancer Network–recommended chemotherapy but primarily involved treatment before 2012, when dose capping was recommended for patients with higher body surface areas. Updated analyses in the contemporary treatment era are warranted. Methods In a retrospective cohort of patients with newly diagnosed ovarian cancer receiving curative-intent carboplatin plus paclitaxel in the Yale-Smilow Cancer Network (2012-2022), we evaluated BMI at diagnosis in relation to relative dose intensity (RDI)—the ratio of completed chemotherapy dose intensity to the National Comprehensive Cancer Network–recommended dose intensity—which reflects dose modification both before and during treatment. We also assessed starting RDI (which reflects modifications before treatment) and received RDI (which reflects modifications during treatment). Data on hospitalizations and hematological chemotoxicities were collected. We examined the association between BMI (<25, 25-30, ≥30) and chemotherapy completion, hospitalizations, and toxicities using multivariable linear and logistic regressions. Results Among 327 patients, the average RDI was 79.7%, and 44.3% had an RDI below 85%. Mean (SD) starting and received RDI were 97.9% (9.1%) and 81.8% (25.7%), respectively. Higher BMI was associated with higher RDI (Paggregate = .03) and received RDI (Paggregate = .04). Body mass index was not associated with starting RDI, dose reductions, delays, hospitalizations, or hematological toxicities. Conclusions Among patients with ovarian cancer treated since 2012, the overall RDI was low. Relative dose intensity was higher among patients with a BMI of 25 or higher compared with a BMI below 25. Most dose modifications occurred during treatment and not before initiation. Studies with body composition data and interventions that maximize chemotherapy completion during treatment are warranted.