Cancer is a major cause of morbidity and mortality worldwide, and the incidence is increasing, highlighting the need for effective strategies to treat this disease. Exercise has emerged as fundamental therapeutic medicine in the management of
cancer, associated with a lower risk of recurrence and increased survival. Several avenues of research demonstrate reduction in growth, proliferation, and increased apoptosis of
cancer cells, including breast, prostate, colorectal, and
lung cancer, when cultured by serum collected after exercise in vitro (i.e., the cultivation of
cancer cell lines in an experimental setting, which simplifies the biological system and provides mechanistic insight into cell responses). The underlying mechanisms of exercise-induced
cancer suppressive effects may be attributed to the alteration in circulating factors, such as skeletal muscle-induced
cytokines (i.e.,
myokines) and
hormones. However, exercise-induced
tumor suppressive effects and detailed information about training interventions are not well investigated, constraining more precise application of exercise medicine within clinical oncology. To date, it remains unclear what role different training modes (i.e., resistance and aerobic training) as well as volume and intensity have on exercise-conditioned serum and its effects on
cancer cells. Nevertheless, the available evidence is that a single bout of aerobic training at moderate to vigorous intensity has
cancer suppressive effects, while for chronic training interventions, exercise volume appears to be an influential candidate driving
cancer inhibitory effects regardless of training mode. Insights for future research investigating training modes, volume and intensity are provided to further our understanding of the effects of exercise-conditioned serum on
cancer cells.