Strength training interventions for cancer patients are safe and well tolerated, having the potential to increase muscle mass and strength and subsequently improve physical function and quality of life, according to a team of Latvia-based investigators.

Training with an intensity higher than the adaptive threshold of 66 to 70 percent of one repetition maximum (1RM) is preferable if the intervention is to induce great physiological adaptations and thus enhance faster recovery from specific cancer treatment, they said.

In the study, the investigators reviewed 50 articles involving physical activity interventions in cancer patients. Summary data showed that prior to initiation of cancer treatment, muscle mass was lower by 0.9 kg in the group of newly diagnosed cancer patients with mixed diagnoses (lung, gastric, colorectal, breast and pancreas cancer) than in the healthy control group. [ESMO Asia 2017, abstract 84P]

During adjuvant chemotherapy, early-stage breast cancer patients notably lost about 1.3 kg of lean body mass (LBM), which continued to decline even after therapy completion. Breast cancer survivors had 20 to 30 percent lower muscle strength compared with healthy individuals at post-treatment follow-up.

In the context of muscle wasting, strength training interventions appeared to be beneficial to cancer patients, yielding strength improvements that led to increased physical function and quality of life.

Training intensity factored in increasing muscular strength and rate of force development. Specifically, training had to be performed at a minimum intensity of 66 percent of 1RM to be able to induce changes in muscle strength.

The investigators noted, however, that most physical activity interventions that have been used in breast cancer studies combined endurance training with strength training and relaxation therapies, thus making it difficult to assess an effect of training type.

Furthermore, there had been a limited amount of studies on breast cancer patients that included higher intensity strength training.

“Cancer and [its] treatment, accompanied with an inactive lifestyle, may further impair muscle strength and muscle force development characteristics. As a countermeasure, exercise training has been increasingly implemented into the oncology setting,” the investigators said.