Background
Androgen deprivation therapy (ADT) is the mainstay of treatment of advanced prostate cancer and is also used for treating other types of prostate cancer. ADT is associated with a range of adverse side-effects including increased fat mass, decreased lean mass, fatigue and a reduced quality of life (QoL).
ADT also increases the risk of developing cardiovascular disease, diabetes and metabolic syndrome. Previous research has shown improvements in fatigue, QoL, muscular fitness and general physical functioning from structured activity interventions.
Aim
The aim of this Irish study was to evaluate the efficacy of a 6-month individually tailored diet and physical activity (walking) intervention for prostate cancer patients receiving ADT, to help minimise side-effects from ADT.
Methods
Of 158 eligible patients, 94 were randomized: 47 to the intervention arm and 47 to the control arm. Inclusion criteria included planned treatment with ADT for prostate cancer for at least 6 months.
The diet and exercise intervention was based on UK healthy eating and physical activity recommendations and designed to be home-based. Based on a 7-day food diary, dietary advice was tailored to the individual man.
The activity intervention included encouragement to walk at a brisk pace for at least 30 minutes per day, five or more days per week and they were provided with a pedometer.
Intervention participants were contacted by phone every 2 weeks for 3 months and every 3 weeks thereafter to monitor progress and compliance. The control group was contacted every 6 weeks and men were provided with the intervention at the end of the 6 months.
The primary outcome of interest was body composition, including body weight, BMI, fat mass, lean muscle mass and waist-hip ratio (WHR); secondary outcomes included fatigue, QoL, functional capacity, stress and dietary change.
Data were analysed on an intention-to-treat basis. Changes over time were compared between control and intervention groups using analysis of covariance with baseline scores included in the models as covariates.
Results
Of the 94 men randomized, 2 from each group dropped out of the study. Compliance with the walking intervention was about 92%.
Significant reductions in calories, total fat and saturated fat and increased intake of fibre and fruit and vegetables in the intervention group suggested high compliance with the diet intervention.
The intervention group had a significant (p<0.001) reduction in weight, body mass index and percentage fat mass compared to the control group at 6 months; the between-group differences were −3.3 kg (95 % confidence interval (95 % CI) −4.5 to –2.1), −1.1 kg/m2 (95 % CI −1.5 to −0.7) and −2.1 % (95 % CI −2.8 to −1.4), respectively, after adjustment for baseline values.
The intervention resulted in improvements in functional capacity (p<0.001) and dietary intakes but there was the changes in fatigue, QoL and stress scores were not statistically significant.
Conclusion
This study showed that a pragmatic 6-month diet and physical activity intervention can help to improve the adverse body composition changes associated with ADT.
This type of intervention has the advantage of not requiring scheduled exercise programs and the dietary component was not a restrictive diet, but rather dietary education around portion size and calorie control.
The high retention rate in the study suggests the intervention was not too onerous and is a feasible approach to help with the body composition side-effects of ADT.
