“Worldwide, breast cancer remains the most commonly diagnosed cancer in women.1 Due to advancements in treatment approaches for breast cancer, the 5-year survival rate has improved dramatically, and in Canada is approximately 88%.2 Despite the efficacy of treatment in improving survival, women who have undergone treatment for breast cancer face both acute and chronic impairments in various aspects of physical function as a result of their treatment, which may involve a combination of surgery, chemotherapy, radiation therapy, hormonal therapy or other targeted biological therapies.3 Physiotherapists have the potential to play selleck inhibitor an important role in cancer care by identifying
and monitoring changes
in physical function during and following breast cancer treatment, and by prescribing interventions to address deficits in physical function. For the purposes of the present review, three main aspects of physical function have been selected: aerobic capacity, muscular fitness of the upper and lower extremities, and mobility. These aspects of physical function were selected because selleckchem they represent clinically relevant areas of focus for physical therapists, they are commonly assessed in exercise oncology literature, and each has established objective outcome measures available for comparison. Declines in aerobic capacity have been observed during breast cancer treatment, which is likely a combination of the direct and indirect effects of the treatment itself, and associated reduction in physical activity leading to deconditioning.4 Maximal oxygen consumption (VO2max) – the upper all limit to the rate of oxygen utilisation, as measured by a cardiopulmonary exercise test – is the gold standard measurement of cardiorespiratory fitness and the capacity for physical work.5 In clinical populations, VO2max may not be achieved during a cardiopulmonary exercise test, so the peak oxygen consumption (VO2peak)
is used instead. VO2peak is associated with all-cause,6 cardiovascular disease-specific7 and 8 and breast cancer-specific9 mortality. A recent cross-sectional study reported that women diagnosed with breast cancer have a VO2peak on average 27% lower than that expected for healthy sedentary women.10 Although VO2peak has a strong association with health outcomes, cardiopulmonary exercise testing requires expensive, specialised equipment and medical supervision for high-risk individuals, thereby limiting its feasibility. A submaximal exercise test, such as a progressive exercise test that is terminated at 85% of age-predicted maximal heart rate or 70% of heart rate reserve, is often a more feasible alternative in clinical practice because it poses less risk and can be done without collection of expired metabolic gases. VO2max can be estimated with a submaximal exercise test.