Although
pain is common among post-treatment
breast cancer survivors, studies that are longitudinal, identify a case definition of clinically meaningful
pain, or examine factors contributing to
pain in survivors are limited. This study describes longitudinal patterns of
pain in long-term
breast cancer survivors, evaluating associations of body mass index (BMI), physical activity, sedentary behavior with mean
pain severity and above-average
pain. Women newly diagnosed with stages 0-IIIA
breast cancer (N = 1183) were assessed, on average, 6 months (demographic/clinical characteristics), 30 months (demographics), 40 months (demographics,
pain), 5 years (BMI, physical activity, and sedentary behavior), and 10 years (demographics,
pain, BMI, physical activity, and sedentary behavior) post-diagnosis. This analysis includes survivors who completed
pain assessments 40 months post-diagnosis (N = 801), 10 years post-diagnosis (
N = 563), or both (N = 522). Above-average
pain was defined by SF-36 bodily
pain scores ≥1/2 standard deviation worse than age-specific population norms. We used multiple regression models to test unique associations of BMI, physical activity, and sedentary behavior with
pain adjusting for demographic and clinical factors. The proportion of survivors reporting above-average
pain was higher
at 10 years than at 40 months (32.3 vs. 27.8 %, p < 0.05). Approximately one-quarter of survivors reported improved
pain, while 9.0 % maintained above-average
pain and 33.1 % reported worsened
pain. Cross-sectionally
at 10 years,
overweight and obese survivors reported higher
pain than normal-weight survivors and women meeting physical activity guidelines were less likely to report above-average
pain than survivors not meeting these guidelines (p < 0.05). Longitudinally,
weight gain (>5 %) was positively associated, while meeting physical activity guidelines was inversely associated, with above-average
pain (OR, 95 % CI = 1.76, 1.03-3.01 and 0.40, 0.20-0.84, respectively) (p < 0.05).
Weight gain and lack of physical activity place
breast cancer survivors at risk for
pain long
after treatment ends. Weight control and exercise interventions should be tested for effects on long-term
pain in these women.