Weight Change and Associated Factors in Long-Term Breast Cancer Survivors

Weight gain often occurs after breast cancer diagnosis and significantly impacts the general health of cancer survivors. While the number of breast cancer survivors is increasing, few studies have reported data on weight change beyond 5 years post-diagnosis. We investigated weight change and associated factors in long-term survivors of breast cancer.

Medical records were reviewed on 1363 breast cancer patients and a total of 822 women who had survived beyond 5 years since diagnosis were included in the final analysis. The association between demographic, anthropometric, lifestyle, cancer related factors (including time since diagnosis, treatment modality, pathologic stage, and hormone receptor status), and weight-change over 5 years were examined.

During an average 8.2 years of follow-up time, mean weight gain was 0.32kg (p = 0.017). 175 (21.3%) patients had gained more than 5% of their weight at diagnosis and their average gain was 5.55kg. Body mass index (BMI) at diagnosis, age at diagnosis, aromatase inhibitor (AI) use, heavy drinking, and type of surgery were associated with relative weight gain (≥5%) in univariate analysis (all p-values<0.05). Patients who were non-obese at diagnosis showed weight gain, while those who were obese at diagnosis lost weight (0.78kg,-1.11kg, respectively, p<0.001). In multivariate analysis, the non-obese group showed odds ratio of 2.7 (p = 0.001) relative to the obese group. Younger age group (age 18-54 years) showed odds ratio of 1.9 (p = 0.021) relative to the older age group (age 55-75 years), and patients who did not use AI showed odds ratio of 2.2 (p = 0.006) relative to women who did.

Long-term breast cancer survivors who were non-obese at diagnosis are more likely to gain weight than obese survivors. Younger survivors and survivors who have never used AI are also likely to gain weight.