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.