Department of Medical Oncology, Harbin Medical University Cancer Hospital, Harbin, China.
Department of Breast Oncology, Aichi Cancer Center, Nagoya, Japan.
Breast Cancer Res. 2021 Feb 4;23(1):18. doi: 10.1186/s13058-021-01397-9.
To evaluate weight change patterns over time following the diagnosis of breast cancer and to examine the association of post-diagnosis weight change and survival outcomes in Black and White patients.
The study included 2888 women diagnosed with non-metastatic breast cancer in 2000-2017 in Chicago. Longitudinal repeated measures of weight and height were collected, along with a questionnaire survey including questions on body size. Multilevel mixed-effects models were used to examine changes in body mass index (BMI). Delayed entry Cox proportional hazards models were used to investigate the impacts of changing slope of BMI on survival outcomes.
At diagnosis, most patients were overweight or obese with a mean BMI of 27.5 kg/m and 31.5 kg/m for Blacks and Whites, respectively. Notably, about 45% of the patients had cachexia before death and substantial weight loss started about 30 months before death. In multivariable-adjusted analyses, compared to stable weight, BMI loss (> 0.5 kg/m/year) showed greater than 2-fold increased risk in overall survival (hazard ratio [HR] = 2.60, 95% CI 1.88-3.59), breast cancer-specific survival (HR = 3.05, 95% CI 1.91-4.86), and disease-free survival (HR = 2.12, 95% CI 1.52-2.96). The associations were not modified by race, age at diagnosis, and pre-diagnostic weight. BMI gain (> 0.5 kg/m/year) was also related to worse survival, but the effect was weak (HR = 1.60, 95% CI 1.10-2.33 for overall survival).
BMI loss is a strong predictor of worse breast cancer outcomes. Growing prevalence of obesity may hide diagnosis of cancer cachexia, which can occur in a large proportion of breast cancer patients long before death.
评估乳腺癌诊断后随时间的体重变化模式，并研究黑人和白人患者诊断后体重变化与生存结果的关系。
本研究纳入了 2000 年至 2017 年在芝加哥诊断为非转移性乳腺癌的 2888 名女性。收集了体重和身高的纵向重复测量值，以及包括身体大小问题的问卷调查。使用多级混合效应模型来检查体重指数（BMI）的变化。延迟进入 Cox 比例风险模型用于研究 BMI 斜率变化对生存结果的影响。
在诊断时，大多数患者超重或肥胖，黑人的平均 BMI 为 27.5kg/m，白人的平均 BMI 为 31.5kg/m。值得注意的是，约 45%的患者在死亡前患有恶病质，大量体重减轻始于死亡前约 30 个月。在多变量调整分析中，与体重稳定相比，BMI 下降（>0.5kg/m/年）与总生存（风险比[HR]2.60，95%CI 1.88-3.59）、乳腺癌特异性生存（HR 3.05，95%CI 1.91-4.86）和无病生存（HR 2.12，95%CI 1.52-2.96）的风险增加了两倍以上。这些关联不受种族、诊断时年龄和预诊断体重的影响。BMI 增加（>0.5kg/m/年）也与较差的生存结果相关，但影响较弱（HR 1.60，95%CI 1.10-2.33 用于总生存）。
BMI 下降是乳腺癌不良预后的一个强有力的预测因子。肥胖的患病率不断增加可能掩盖了癌症恶病质的诊断，这种情况可能在患者死亡前很长一段时间就会在很大一部分乳腺癌患者中发生。
