Response to commentary on: ‘Exercise training in breast cancer survivors: a review of trials examining anthropometric and obesity-related biomarkers of breast cancer risk’

Abstract

The authors would like to thank Campbell and Neil for their commentary 1 on a recently published review by Guinan, Connolly and Hussey 2 which explores the effect of exercise training in breast cancer survivors on anthropometric and obesity-related biomakers of breast cancer risk outcomes. We welcome discussion on this topic which, due to the increasing number of breast cancer survivors, is becoming a public health issue that needs to be addressed by physical therapists with proficient skills in prescribing exercise in clinical populations. Of course, the issues addressed explore the impact of physical activity on many diseases where obesity and inactivity are risk factors, e.g. cardiovascular disease. Breast cancer survivors however, characterize a unique group for whom physical activity may impact on not only chronic disease risk factors but also breast cancer-specific outcomes including risk of recurrence and mortality. Data from our research group have described breast cancer survivors, in the first number of years following adjuvant treatment, as largely overweight or obese and/or centrally obese and physical inactive, 3,4 which led to the need to implement exercise interventions in addition to healthy weight strategies early in the cancer trajectory.Campbell and Neil correctly point out that exercise alone, in the absence of diet modification, is not sufficient to produce meaningful, long-lasting weight loss. The end-points examined in the review by Guinan et al. 2 were termed 'obesity-related biomakers' and were therefore inherently related to adiposity. Campbell and Neil discuss the results of a recent four-arm randomized control trial by Foster-Schubert and colleagues, 5 comparing the effect of four different interventions: (i) aerobic exercise; (ii) weight loss (calorie restriction); (iii) exercise and weight loss (calorie restriction); and (iv) usual care control group on selected biomarkers. The results of this trial are similar to others 6-8 in suggesting that the benefits to be gained from exercise combined with weight loss through calorie restriction are superior to those stimulated by either exercise or diet modification alone.In relation to breast cancer, both physical activity and maintenance of a healthy body weight are associated with improved survival and breast cancerrelated outcomes. 9,10