Impact of neoadjuvant chemotherapy on perioperative nutritional status in breast cancer patients: a prospective cohort study

<h2>Abstract</h2><h3>Background</h3> Neoadjuvant chemotherapy (NAC) is effective in reducing tumor size and improving surgical outcomes for patients with inflammatory, unresectable, or locally advanced breast cancer (BC). However, malnutrition frequently occurs during NAC, increasing the risk of perioperative complications and hindering progress in enhanced recovery after surgery. The impact of NAC on overall nutritional status, as well as specific nutritional components, throughout the perioperative period in BC patients remains unclear. This study aims to provide insight by longitudinally tracking the nutritional status of BC patients undergoing NAC compared to those who do not. <h3>Methods</h3> We conducted a prospective study at a tertiary hospital in China, enrolling BC patients who met the inclusion criteria of a confirmed diagnosis of invasive BC without significant comorbidities. Patients with metastatic disease or a prior history of BC treatment were excluded. After obtaining written informed consent, participants were assigned to either a NAC cohort or a surgery-first cohort based on clinical decision-making factors, such as tumor histology, grade, stage, and estrogen, progesterone, and HER2 receptor status. Baseline data (one day before surgery, T0) and follow-up data (first day after surgery, T1; the seventh day after surgery, T2) were gathered through self-reported questionnaires, blood tests, and InBody 770 (InBody Co., Ltd., Korea) measurements. The primary outcome was nutritional status, assessed by phase angle. Baseline differences between the NAC and surgery-first cohorts were analyzed using independent sample t-tests or the Mann-Whitney U test. Repeated measures ANOVA was used to evaluate changes in the collected data across T0, T1, and T2. This study was approved by the ethics committee of the hospital (No. SL-II2024-199-01). <h3>Findings</h3> This study included 32 breast cancer patients, with 13 enlisted in the NAC cohort and 19 in the surgery-first cohort. Phase angle, albumin, and total protein have significant differences in the baseline data (p < 0.001). Moreover, phase angle significantly decreased in both cohorts (p < 0.001), with a greater reduction in the NAC group (T0: 4.52 ± 0.62, T1: 4.09 ± 0.73, T2: 4.34 ± 0.84) compared to the surgery-first group (T0: 5.13 ± 0.46, T1: 4.55 ± 0.49, T2: 4.90 ± 0.39). In the NAC group, the most prominent changes observed from T0 to T2 were in basal metabolic rate (kcal/day) (from 1224.85±109.82 to 1216.62±100.78), arm circumference (cm) (from 29.21±3.24 to 28.99±3.14), and protein levels (g/dL) (from 7.62±1.00 to 7.58±0.92). Meanwhile, in the surgery-first group, the most prominent changes from T0 to T2 included basal metabolic rate (kcal/day) (from 1217.16±98.23 to 1212.05±102.67), percent body fat (%) (from 33.33±8.61 to 32.96±7.95), and fat-free mass (kg) (from 39.23±4.54 to 38.98±4.76). <h3>Interpretation</h3> The findings suggest that NAC is associated with a more pronounced postoperative decline in nutritional status, indicating that chemotherapy may exacerbate catabolic processes, thereby influencing recovery and nutritional stability. This study emphasizes the importance of early nutritional monitoring in BC patients undergoing NAC and highlights the need to explore the optimal timing and types of nutritional interventions to improve overall patient prognosis.