A 15-year follow-up study on long-term adherence to health behaviour recommendations in women diagnosed with breast cancer.

BACKGROUND: Whilst a cancer diagnosis may prompt health behaviour change, there is limited evidence regarding whether such changes are maintained in the long-term. We aimed to investigate the impact of cancer diagnosis on health behaviour changes over the long-term survivorship period among breast cancer survivors (BCSs).
METHODS: The sample comprised 153 BCSs and 4778 cancer-free women, aged 49-55 years in 2001 (our baseline), from the 1946-1951 birth cohort of the Australian Longitudinal Study on Women's Health. Health behaviours (physical activity, smoking, alcohol, diet and Body Mass Index), recommended by the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR), were assessed in five survivorship periods: ≤ 3 years, 3 to ≤ 6 years, 6 to ≤ 9 years, 9 to ≤ 12 years, and 12 to 15 years since diagnosis. A validated semi-quantitative Food Frequency Questionnaire was used for dietary assessment. Pre-diagnosis (baseline) health behaviours of BCSs and cancer-free women were compared (using Generalized Linear Models (GLM)). Multilevel (mixed effect) models were used for longitudinal data in BCSs.
RESULTS: There was no significant difference in health behaviours between BCSs (prior to diagnosis) and cancer-free women. Following diagnosis, BCSs were significantly more physically active (≥ 600 MET min/week; 50.8% to 63.3%; p = 0.02) and consumed more fruit (≥ 2 serves/day; 57.4% to 66.4%; p = 0.01) in the recent survivorship period, but were less likely to be classified in the healthy weight range (p < 0.01). The proportion of non-drinkers and non-smokers slightly increased over the survivorship period. Whole-vegetable intake did not significantly change; however, the intake of non-starchy vegetables significantly increased from pre-diagnosis (LS mean = 89.1 g/day) to post-diagnosis, 6 to ≤ 9 years (LS mean = 137.1 g/day), and 9 to ≤ 12 years (LS mean = 120.8 g/day). There were no significant changes in the total intake of fibre, carotenoids, calcium, fat, saturated fat, vitamin C, or vitamin E observed, except for increased total energy intake (p = 0.012).
CONCLUSION: Before diagnosis, BCSs had similar adherence to health behaviours compared to cancer-free women. Initial positive changes to health behaviours were observed post BC diagnosis, except healthy body weight, but maintenance of such changes over the long-term was poor. BCSs may benefit from additional advice and support to make healthy lifestyle choices throughout survivorship.