Title: Weight and waist-to-hip ratio change pattern during the first five years of survival: data from a longitudinal observational Chinese breast cancer cohort

Background: Body weight management was an important component in breast cancer survivorship care. The present study described the change patterns of body weight and waist-to-hip ratio (WHR) during the first five years of survival, and investigated potential factors associated with very substantial changes.Patients and methods: Based on a longitudinal cohort with 1462 Chinese women with breast cancer, anthropometric measurements including body weight, height, waist and hip circumferences were measured by trained interviewers following standard protocol at four time-points: baseline at study entry, 18-, 36- and 60-months follow up assessments (termed as T0, T1, T2 and T3, respectively). Body height was measured at baseline and body weight at cancer diagnosis were retrieved from medical record.Results: Compared to weight at breast cancer diagnosis, the median weight change was -0.5kg, 0kg, +0.5kg, and +1kg at T0, T1, T2 and T3, respectively. During the first five years of survival, the proportion of women who were obese have slightly increased. At 60-months after diagnosis, only 14.3% of women had weight gain by > 5kg; and the percentage of women who had weight gain by > 10% was 10.7%. Nearly half of patients had abdominal obesity at study entry, and this proportion were gradually increased to nearly 70% at 60-months follow-up. Multivariate analysis indicated that older age, frequent sports participation and having vegetables and fruits intake ≥ 400g/day were related to lower risk of very substantial weight gain (> 10%) at 60-months follow-up; patients aged 40-49 years, having ≥ 2 comorbidities, ER negative and having vegetables and fruits intake ≥ 400g/day were associated with less likelihood of very substantial WHR substantial increase (> 10%) at 60-months follow-up. Conclusion: Weight gain was modest in Chinese breast cancer survivors during the first five years of survival, while central adiposity has become a contemporary public health issue. The incorporation of healthy weight and abdominal circumference patient education and management has a potential to improve cancer survivorship.