Abstract P3-03-22: Overweight and obesity trends over 5 years in early stage and metastatic breast cancer patients
Authors: Tsou Terrence , Blackford Amanda L. , Stearns Vered , Sheng Jennifer Y. 
Published: March 2023

Background: Obesity is associated with 25-33% of all breast cancer (BC) cases, and BC survivors with obesity have a 35% higher risk of BC-related death and 41% higher risk of all-cause mortality. We hypothesized that the prevalence of overweight (body mass index [BMI] 25-29.9 kg/m2) and obesity (BMI ≥30) after a diagnosis of early stage or metastatic BC increases, and baseline characteristics may increase risk of weight gain.

Methods: We conducted a retrospective chart review of 222 patients with Stage 0-IV BC who newly presented to Johns Hopkins from 2015-2018. Patients were part of the BC Program Quality Improvement Project Database, had 1 chest CT scan within 6 months of initial visit, and at least 1 subsequent CT. Data extracted from the medical record included: demographics, menopausal status, diagnosis date, cancer characteristics/treatment, recurrence/vital status, family history of BC, and tobacco/alcohol use. All BMI measured on patients were collected. Baseline BMI was defined as the closest measurement to BC diagnosis between 1 year prior and 1 month after diagnosis. We estimated time to overweight/obesity from diagnosis using the Kaplan Meier method and compared between subgroups with the log rank test. Patients who were overweight/obese at diagnosis were included in the analysis with an event time of zero.

Results: Among 222 patients, 110 patients (50%) had newly diagnosed early-stage BC, 98 (44%) had de-novo or recurrent metastatic BC, and 14 (6.3%) had locally recurrent BC. Most patients were women (98%) and non-Hispanic (93%). Patients identified as White (62%), Black (23%), and Asian (8%). Among 34% with alcohol use, 5% reported ≥8 drinks/week. There were current (6%) and former smokers (34%). Family history of BC was present in 10%. Among those with early-stage primary BC, most were postmenopausal (61%) and received chemotherapy (61%). Hormone receptor (HR)-positive, HER2-positive and triple negative subtypes were 70%, 24% and 19%, respectively. For those with metastatic BC, most were postmenopausal (62%). Hormone receptor (HR)-positive, HER2-positive and triple negative subtypes were 71%, 12% and 24%. At diagnosis, 73% of the whole cohort had BMI ≥25 kg/m2, with the whole cohort and subgroups having mean BMI ≥25 kg/m2. The incidence of elevated BMI increased in all groups and overall, over 5 years (Table 1). Weight gain was significantly associated with premenopausal status (p=0.04). Stage at diagnosis, smoking/alcohol use, receipt of chemotherapy/radiation/endocrine therapy, and subtype were not associated with weight gain.

Conclusion: Patients with early stage and metastatic BC have elevated BMI at diagnosis, and this risk increases over 5 years, especially for those who are premenopausal. Further investigation of the implications of these changes is needed. Additionally, while BMI is accessible, it may underestimate body fat in older people and others who have lost muscle, does not identify fat distribution (a major factor in metabolic health risk), and may not be equally valid across gender, race and ethnicities and age groups. We will assess body composition by CT scan and report correlations with BMI and cancer-related outcomes.

Prevalence of BMI≥25 kg/m2 in patients with breast cancer at diagnosis and by 1-, 2-, and 5-years after Prevalence of BMI≥25 kg/m2 increased over 5 years post-diagnosis. Premenopausal status was more associated with BMI≥25 kg/m2 versus postmenopausal status.

Citation Format: Terrence Tsou, Amanda L. Blackford, Vered Stearns, Jennifer Y. Sheng. Overweight and obesity trends over 5 years in early stage and metastatic breast cancer patients [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-03-22.