Body composition is an important predictor in cancer patients, with skeletal muscle loss and high adiposity associated with poorer prognosis. This study evaluated how body composition affects treatment efficacy in 48 women with metastatic breast cancer receiving trastuzumab deruxtecan. Using computed tomography, skeletal muscle, visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were assessed within 60 days before initiating treatment. High SAT and VAT areas were significantly associated with a higher likelihood of dose reductions (Odds Ratio [OR] = 5.34, p = .032 and OR = 5.52, p = 0.032, respectively). Higher SAT areas correlated with a lower objective response rate (OR = 0.22, p = 0.047). Medium SAT and low/medium VAT densities increased the risk of dose reductions. A body mass index over 25 kg/m² was linked to higher dose reductions (OR = 4.97, p = 0.016). These findings emphasize the need for personalized treatment strategies based on body composition.

In this study, we explore recruitment, retention, and potential quality of life (QoL) and function benefits from a self-directed, home-based walking intervention in women during active treatment for metastatic breast cancer (MBC). In this single-arm pilot study, women with stage IV BC wore an activity tracker (FitbitTM) to measure steps per week throughout the intervention study. Participants were asked to walk 150 min per week at a comfortable and safe pace. Patient-reported outcome measures (PRO) were collected at baseline and follow-up. Target recruitment of 60 patients was achieved. In 52 patients who completed all baseline measures, mean age was 55 (SD 11.1), 23% were pre-menopausal, and 19% non-White. Forty patients (77%) were retained at 3 months and 29 (56%) at 6 months. Baseline walking was the strongest predictor of retention at 3 months (P = .02). For 24 patients (46%) with analyzable Fitbit data at 3 months, mean steps/week rose from 19,175 to 31,306. Higher number of steps correlated with larger improvements FACT-G General well-being (FACT-G, rho = 0.55, P = .01), FACT-G Physical well-being (rho = 0.48, P = .03), and PROMIS Mental Health (rho = 0.55, P = .01). Recruitment into a walking intervention is feasible (a priory target of N = 60) in women during treatment for MBC, but retention at 3 months follow-up fell short (77% versus a priori 80%), yet there were potential benefits in general and physical well-being and mental health. NCT02682836.

This real-world cohort analysis assessed the efficacy of alpelisib and endocrine treatment (ET) combinations in a post-everolimus setting. Thirteen women who started alpelisib and ET at standard doses between 2018 and 2022 for advanced breast cancer (ABC), after undergoing CDK4/6i and everolimus treatment, were eligible for the study entry. The primary endpoint was progression-free survival (PFS), and the secondary endpoints were the objective response rate (ORR) and clinical benefit rate (CBR), with different molecular profiling. The patients had previously received a median of four (range 3–8) systemic treatments, including CDK4/6i and everolimus. The median PFS on alpelisib was 5.5 months (range 0.5–10), and four women each had an ORR and three (23%) had a stable disease. The 6-month CBR was 46.1%, similar to the BYLeive study cohort C (47.8%). Notably, our cohort included patients with a long CBR under everolimus treatment (median 6 months, range 1–18); however, the responses to alpelisib and everolimus were not correlated (Pearson r = −0.23, p = 0.44). The PIK3CA, P53, ARID, GATA3, and ESR1 mutations were not associated with the 6-month CBR. Despite heavy pre-treatments, including everolimus, alpelisib was clinically relevant in our cohort, even among patients with an ESR1 mutation. The best treatment sequence for PIK3CA/mTOR inhibitors warrants examination in future trials on PIK3CA-mutant inpatients with luminal ABC.